Abstract This paper is the first part of a two-part study aiming to introduce a new integrated approach to evaluate the techno-economic value of recuperator retrofit on existing gas turbine engines. The original gas turbines are designed for combined cycles so that the pressure ratios are moderate to secure suitable exhaust temperatures. One way to enhance the thermal efficiency of some gas turbines is by using recuperation to recover some of the exhaust heat. In this part, the developed model is described and implemented for two gas turbine engines so the obtained characteristics are evaluated against the actual data. The new approach will assist users to select the suitable gas turbine models with favorable recuperator characteristics based on a technical and economic prospective. Besides, the performance results are used to design an appropriate shell and tube heat exchanger. Moreover, a new technique has been established to define the typical heat exchanger parameters in order to ensure the highest possible improvements over the original cycles. One of the main features of this method is that it depends only on the velocity of hot and cold heat exchanger streams from which the rest of the heat exchanger design and performance characteristics were derived. Key Words: integrated approach, techno-economic value, recuperation, shell and tube heat exchanger, velocity
Thermal analysis of cooling effect on gas turbine bladeeSAT Journals
This document analyzes the film cooling technique used to cool gas turbine blades where temperatures exceed 1122 K. It finds that the thermal efficiency of a cooled gas turbine is slightly lower than an uncooled one due to the decreased turbine inlet temperature from cooling. However, cooling is necessary to increase blade life as temperatures rise above 1123K. The document also examines how increasing the overall pressure ratio further decreases the net power output of cooled gas turbines.
Validation of Design Parameters of Radiator using Computational ToolIRJET Journal
This document discusses the validation of design parameters for automobile radiators using computational tools. It presents two case studies where the thermal performance of radiators is analyzed using the log mean temperature difference (LMTD) and number of transfer units (NTU) methods and the results are compared to those from a computational software tool (HXCombine). The results show good agreement between the manual calculations and software outputs, validating the use of computational tools for radiator design. Parameters like heat transfer rate, outlet temperatures, effectiveness and heat transfer area are compared for both case studies. This research demonstrates that computational tools can accurately analyze and design radiator performance.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Thermal analysis of water cooled charge air cooler in turbo charged diesel en...eSAT Journals
This document analyzes the thermal performance of a water-cooled charge air cooler used in a turbocharged diesel engine. It describes the components and working of air-cooled and water-cooled charge air coolers. It then analyzes the performance of a plate fin heat exchanger model of the water-cooled charge air cooler by calculating various parameters using correlations. The results obtained by varying the hot air flow rate show that the Colburn-j factor and friction factor decrease while heat transfer coefficient, overall heat transfer coefficient increase with Reynolds number, and effectiveness decreases with increasing air mass flow rate.
Optimization of time step and cfd study of combustion in di diesel engineeSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
This document summarizes the results of a thermal analysis of a gas turbine power plant to improve performance efficiency. The analysis considers three gas turbine cycles: simple cycle, intercooled cycle, and regenerative cycle. For the intercooled cycle, the analysis found that thermal efficiency increases with higher intercooler effectiveness and decreases with higher ambient temperature. Compressor work also decreases with higher intercooler effectiveness. For the regenerative cycle, thermal efficiency decreases with higher ambient temperature and lower regenerator effectiveness. The regenerative cycle has higher thermal efficiency than the simple cycle under the same operating conditions. The analysis provides equations to calculate key performance parameters for optimizing efficiency.
IRJET-Detailed Energy Audit in a Captive Cogeneration PlantIRJET Journal
D.Rajani Kant , B.Sudheer Prem Kumar, N.Ravi Kumar, R.Virendra,J.Suresh Babu " Detailed Energy Audit in a Captive Cogeneration Plant ", International Research Journal of Engineering and Technology (IRJET), Volume2,issue-01 April 2015.e-ISSN:2395-0056, p-ISSN:2395-0072. www.irjet.net
Abstract
The rate of exploitation of the energy resources has been expanding over time and resulted in reduction of fossil fuel reserves. Efficiency of all resources is crucial both in environmental and economic sense. Using energy inefficiently creates waste in all the world’s economies. It has environmental impacts with regional, local and global implications.The key object is to adopt energy management in every field in order to reduce the wastage of energy sources and cost effectiveness without affecting productivity and growth.
An approach to evaluate the heat exchanger retrofit for installed industrial ...eSAT Journals
This document summarizes an economic evaluation of retrofitting heat exchangers to existing industrial gas turbines to improve their efficiency. It describes using the net present value method to compare the economics of simple cycle and recuperative cycle configurations for two gas turbine models. The analysis found that retrofitting heat exchangers can increase the net present value over the simple cycle, with differences ranging from $11 million to over $46 million depending on the turbine model and assumptions. However, the payback period for the retrofit may be longer, and the analysis also examined the effects of utilization rate and other factors on the economic viability.
Thermal analysis of cooling effect on gas turbine bladeeSAT Journals
This document analyzes the film cooling technique used to cool gas turbine blades where temperatures exceed 1122 K. It finds that the thermal efficiency of a cooled gas turbine is slightly lower than an uncooled one due to the decreased turbine inlet temperature from cooling. However, cooling is necessary to increase blade life as temperatures rise above 1123K. The document also examines how increasing the overall pressure ratio further decreases the net power output of cooled gas turbines.
Validation of Design Parameters of Radiator using Computational ToolIRJET Journal
This document discusses the validation of design parameters for automobile radiators using computational tools. It presents two case studies where the thermal performance of radiators is analyzed using the log mean temperature difference (LMTD) and number of transfer units (NTU) methods and the results are compared to those from a computational software tool (HXCombine). The results show good agreement between the manual calculations and software outputs, validating the use of computational tools for radiator design. Parameters like heat transfer rate, outlet temperatures, effectiveness and heat transfer area are compared for both case studies. This research demonstrates that computational tools can accurately analyze and design radiator performance.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Thermal analysis of water cooled charge air cooler in turbo charged diesel en...eSAT Journals
This document analyzes the thermal performance of a water-cooled charge air cooler used in a turbocharged diesel engine. It describes the components and working of air-cooled and water-cooled charge air coolers. It then analyzes the performance of a plate fin heat exchanger model of the water-cooled charge air cooler by calculating various parameters using correlations. The results obtained by varying the hot air flow rate show that the Colburn-j factor and friction factor decrease while heat transfer coefficient, overall heat transfer coefficient increase with Reynolds number, and effectiveness decreases with increasing air mass flow rate.
Optimization of time step and cfd study of combustion in di diesel engineeSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
This document summarizes the results of a thermal analysis of a gas turbine power plant to improve performance efficiency. The analysis considers three gas turbine cycles: simple cycle, intercooled cycle, and regenerative cycle. For the intercooled cycle, the analysis found that thermal efficiency increases with higher intercooler effectiveness and decreases with higher ambient temperature. Compressor work also decreases with higher intercooler effectiveness. For the regenerative cycle, thermal efficiency decreases with higher ambient temperature and lower regenerator effectiveness. The regenerative cycle has higher thermal efficiency than the simple cycle under the same operating conditions. The analysis provides equations to calculate key performance parameters for optimizing efficiency.
IRJET-Detailed Energy Audit in a Captive Cogeneration PlantIRJET Journal
D.Rajani Kant , B.Sudheer Prem Kumar, N.Ravi Kumar, R.Virendra,J.Suresh Babu " Detailed Energy Audit in a Captive Cogeneration Plant ", International Research Journal of Engineering and Technology (IRJET), Volume2,issue-01 April 2015.e-ISSN:2395-0056, p-ISSN:2395-0072. www.irjet.net
Abstract
The rate of exploitation of the energy resources has been expanding over time and resulted in reduction of fossil fuel reserves. Efficiency of all resources is crucial both in environmental and economic sense. Using energy inefficiently creates waste in all the world’s economies. It has environmental impacts with regional, local and global implications.The key object is to adopt energy management in every field in order to reduce the wastage of energy sources and cost effectiveness without affecting productivity and growth.
An approach to evaluate the heat exchanger retrofit for installed industrial ...eSAT Journals
This document summarizes an economic evaluation of retrofitting heat exchangers to existing industrial gas turbines to improve their efficiency. It describes using the net present value method to compare the economics of simple cycle and recuperative cycle configurations for two gas turbine models. The analysis found that retrofitting heat exchangers can increase the net present value over the simple cycle, with differences ranging from $11 million to over $46 million depending on the turbine model and assumptions. However, the payback period for the retrofit may be longer, and the analysis also examined the effects of utilization rate and other factors on the economic viability.
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Graph 3. Variation of power and efficiency with pressure at temperature at 4500C
This document summarizes the results of a sensitivity analysis performed on a heat recovery steam generator (HRSG) for a GE 6FA gas turbine combined cycle power plant. The analysis varied the steam pressure from 40 to 62 atmospheres and steam temperature from 400 to 500 degrees Celsius to determine the optimal operating point. The maximum power and efficiency were achieved at different pressure-temperature combinations, with 58 atmospheres generally providing the best results for temperatures between 450-500 degrees Celsius. Graphs show the relationships between pressure, power, efficiency
This document discusses steam turbine power plant design and cycles. It describes typical steam conditions between 600-1450 psig at 750-950°F for Army power plants. Back pressure turbines exhaust at 250-15 psig and condensing turbines exhaust at 1-5 inches of mercury absolute. Cogeneration plants use back pressure or controlled extraction/condensing cycles to simultaneously produce electric power and steam for heat. The document compares plant heat rates, turbine heat rates, and discusses optimizing steam power plant cycles for maximum efficiency and economy.
This document summarizes a research paper that analyzed heat transfer in an economizer using computational fluid dynamics (CFD). It discussed how fins can be added to economizer tubes to increase the heat transfer surface area between flue gases and boiler feedwater. The document reviewed previous research on economizer design optimization and failures. It described the working of CFD analysis using equations of continuity, momentum, and energy to model fluid flow. The study used the k-ε turbulence model in CFD software to analyze heat transfer with and without fins on an economizer.
Paper design and optimizaton of steam distribution systems for steam power pl...Tony Lewis
This document presents a methodology for optimizing the design of steam distribution networks (SDNs) for steam power plants. The methodology formulates the problem as a mixed-integer nonlinear programming (MINLP) model to minimize total annualized cost. The model determines the optimal structure, configuration, and operation of the SDN as well as its interaction with the heat recovery system. Case studies are used to demonstrate the feasibility and benefits of the proposed simultaneous optimization approach.
The document summarizes an exergy and exergo-economic analysis of the Montazer Ghaem gas turbine power plant in Iran. The analysis finds that the combustion chamber has the highest exergy destruction due to the large temperature difference between the flame and operating fluid. The gas turbine's performance and efficiency are significantly affected by ambient temperature. An increase in ambient temperature decreases the net power output and exergy efficiency. The exergo-economic analysis determines that the combustion chamber also has the largest cost of exergy destruction.
This document proposes a hybrid PID-cascade control system for HVAC systems to improve control performance. It models the heat exchanger and air conditioning space components of an HVAC system. It then designs a hybrid PID-cascade controller that combines traditional PID control with an internal cascade loop. Simulations show the hybrid controller has faster response, better setpoint tracking and disturbance rejection compared to traditional PID, compensator and Ziegler-Nichols tuned PID controllers. The cascade control inner loop improves response speed and precision, while the outer PID loop enhances stability and disturbance rejection for the HVAC system.
The document describes a computational fluid dynamics (CFD) analysis of heat transfer in a rectangular channel with blockages containing elongated holes. A model of the channel was created in design software and meshed before performing CFD simulations. The simulations analyzed how heat transfer coefficients and Nusselt numbers varied with the pitch ratio of the blockages for different Reynolds numbers. Results showed that heat transfer initially increased with pitch ratio up to a value of 6.0, then decreased with further increases, due to changes in flow reattachment. Blockages with shorter holes enhanced heat transfer more but also increased pressure drops more compared to longer holes. The CFD results were also validated against available experimental data, with good agreement.
IRJET- Comparsion of Heat Transfer Analysis of Double Pipe Heat Exchanger wit...IRJET Journal
This document describes an experimental study comparing heat transfer in a double pipe heat exchanger with and without a phase change material (PCM). Cynamide, which melts at 44°C, was used as the PCM. Hot water at 33°C and cold water at 20°C were circulated through the heat exchangers. Temperatures were recorded every 15 minutes. With the PCM, heat transfer increased when its melting temperature was reached, as the PCM absorbed heat during its phase change. The maximum heat transfer and effectiveness occurred in the setup with the PCM pipe, showing around a 20% increase in effectiveness compared to the setup without PCM. Equations for determining the heat transfer rate, maximum
Analysis of Air Conditioning System used in Automobileijtsrd
Air conditioning has great importance in many areas of life. Especially it is crucial in transportation sector. Many people spend long time in an automotive cabin during business, travel, shopping, etc., every day. The aim of this study is to analyze the performance of a bus shell by considering identifying practical solutions in order to reduce the impact of air conditioning on bus, consumption and, therefore, on air pollution. The analysis is carried considering several parameters, including passenger capacity, local climatic conditions, fuel consumptions, and latitude and longitude of starting destination of the places. For the analysis, a bus with passenger capacity of 60 people is selected and then its heat load capacity will be determined by considering different conditions like seasons and various loads. The influence of the refrigerant decrease and the change of the air temperature which gets to exchangers on the refrigeration efficiency of the system to be analyzed. Also, its effectiveness and the power required to drive the compressor will be analyzed. The entire model, its analysis and results are discussed in the below work. Dr. S. Sreenatha Reddy | P. Akhil | N. Raju | K. Vishnu | N. Ashok ""Analysis of Air Conditioning System used in Automobile"" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-3 , April 2019, URL: https://www.ijtsrd.com/papers/ijtsrd23357.pdf
Paper URL: https://www.ijtsrd.com/engineering/mechanical-engineering/23357/analysis-of-air-conditioning-system-used-in-automobile/dr-s-sreenatha-reddy
Using coolant modulation and pre cooling to avoid turbine bladeRakesh Rauth
This document examines methods to prevent turbine blade overheating when firing a gas turbine combined cycle power plant with low calorific value gas. Decreasing the firing temperature can prevent blade overheating but significantly reduces power output. Modulating the coolant supply to each blade row results in a much lower power penalty compared to under-firing. Pre-cooling the coolant before supplying it to the turbine further enhances power output by reducing the required coolant flow. Pre-cooling recovers 80% of the power gain possible from switching to low calorific value gas while providing higher combined cycle efficiency than under-firing.
Model-based adaptive sliding mode control of the subcritical boiler-turbine s...ISA Interchange
As higher requirements are proposed for the load regulation and efficiency enhancement, the control performance of boiler-turbine systems has become much more important. In this paper, a novel robust control approach is proposed to improve the coordinated control performance for subcritical boiler-turbine units. To capture the key features of the boiler-turbine system, a nonlinear control-oriented model is established and validated with the history operation data of a 300 MW unit. To achieve system linearization and decoupling, an adaptive feedback linearization strategy is proposed, which could asymptotically eliminate the linearization error caused by the model uncertainties. Based on the linearized boiler-turbine system, a second-order sliding mode controller is designed with the super-twisting algorithm. Moreover, the closed-loop system is proved robustly stable with respect to uncertainties and disturbances. Simulation results are presented to illustrate the effectiveness of the proposed control scheme, which achieves excellent tracking performance, strong robustness and chattering reduction.
This document presents models of an electric water heater and air conditioner for use in residential demand response strategies. It describes the development of simulation models for these appliances based on their operational and physical characteristics. The models were validated against real measurement data and found to accurately model the appliances, with low errors. The models can provide insight into control strategies to better evaluate performance in residential demand response implementations.
Handbook of mechanical engineering calculationsRoddy Castro
The document discusses several options for boosting the output of a 230 MW combined cycle power plant using a 155 MW gas turbine. It evaluates seven cases: 1) using an evaporative cooler to precool the gas turbine inlet air, 2) using a mechanical chiller, 3) using an absorption chiller, 4) injecting steam into the gas turbine, 5) injecting water into the gas turbine, 6) partially supplementary firing the heat recovery steam generator, and 7) fully supplementary firing the heat recovery steam generator. Case 1 of using an evaporative cooler increased plant output by 6.65 MW and improved heat rate by 15 Btu/kWh, but had a high capital cost of $180/kW.
Robust control of speed and temperature in a power plant gas turbineISA Interchange
In this paper, an H∞ robust controller has been designed for an identified model of MONTAZER GHAEM power plant gas turbine (GE9001E). In design phase, a linear model (ARX model) which is obtained using real data has been applied. Since the turbine has been used in a combined cycle power plant, its speed and also the exhaust gas temperature should be adjusted simultaneously by controlling fuel signals and compressor inlet guide vane (IGV) position. Considering the limitations on the system inputs, the aim of the control is to maintain the turbine speed and the exhaust gas temperature within desired interval under uncertainties and load demand disturbances. Simulation results of applying the proposed robust controller on the nonlinear model of the system (NARX model), fairly fulfilled the predefined aims. Simulations also show the improvement in the performance compared to MPC and PID controllers for the same conditions.
IRJET- Optimization and CFD Analysis on Profile Elements of Regenerative Rota...IRJET Journal
This document discusses the optimization and computational fluid dynamics (CFD) analysis of different profile elements in a regenerative rotary air preheater. It begins with an introduction to rotary air preheaters and describes the various profile types used as heat transfer elements. Experimental measurements from a coal-fired power plant are presented. CFD models of five profile elements are analyzed to determine their outlet air and flue gas temperatures. The results show that the advanced clear element profile provides the best performance with higher air outlet temperature and lower flue gas outlet temperature compared to other profiles.
Nonlinear multivariable control and performance analysis of an air-handling unitAli Abedi
This document summarizes a study that investigates nonlinear control approaches for an air-handling unit (AHU). A nonlinear multi-input multi-output dynamic model of an AHU is developed. Both indoor temperature and relative humidity are controlled by manipulating air and cold water flow rates. Two nonlinear control approaches, gain scheduling and feedback linearization, are designed and compared. Results show feedback linearization achieves faster tracking of setpoints but with more overshoot, while gain scheduling has less oscillation in control inputs and likely lower energy use. Feedback linearization is also more robust to model parameter uncertainty.
Analysis of Process Parameters to Improve Power Plant EfficiencyIOSRJMCE
This research paper analyses the operational parameters of a thermal power plant to improve effectively & efficient running of the machine while ensuring a degree of compliance with statutory regulations. This study aims to identify the operational gaps associated with running operational parameter in power plant process. It is focused to detect a different thermodynamic variable involved, being multivariate and automatic. For variation of each one of this operational parameters, performance calculations are find out to configure a database of energy variation. The variable data sets now can be used as assessment criteria based on detecting deviations from a reference system that has been updated during plant-performance tests. Although the most important outcome is the highly precise and valuable information that will be obtained on the live operating mode, leading to a head improvements in the cycle efficiency and achieved in the overall control system of the thermal plant. The main aim is to detect any abnormality, reacting as quickly as possible to return the plant to a normal operation mode at best efficient manner.
The document summarizes the development of a new library called Ship Energy Systems for simulating and optimizing ship machinery systems. The library allows modeling of engines, generators, cooling systems and other auxiliary components. It facilitates variant analysis to optimize energy efficiency and quantify potential fuel savings. An example model of a medium-sized freight vessel is presented to demonstrate the library's capabilities. The library reduces the time needed for ship energy simulations compared to developing models from scratch.
A practical approach to design and optimization of single phase liquid to liq...iaemedu
The document describes the design and optimization of a shell and tube heat exchanger. It presents a method based on Tinker's approach that incorporates modifications from Kern and Kakac. A 17-step thermal design procedure is outlined that involves sizing the heat exchanger dimensions and components through an iterative process to meet a specified heat load. A computer program was developed to automate the calculations and optimize the design in a more efficient manner than manual calculations. The program allows the user to input parameters and obtain an optimized design solution.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
The document summarizes an energy audit conducted on a thermal power plant in Jordan. The power plant produces 14.36 MW through a Rankine cycle using natural gas. A preliminary energy audit evaluated the performance of the plant's components, including the boiler, turbine, condenser, and pumps. The results showed deviations in efficiency for all components compared to their design specifications. Specifically, the boiler had the largest deviation of 4.9% efficiency, likely due to poor water and fuel quality and heat loss. Several solutions were proposed to improve the plant's efficiency.
Optimization of Organic Rankine Cycle’s thermal efficiency based on Grey rela...IRJET Journal
This document summarizes a study that used the Taguchi method and grey relational analysis to optimize the thermal efficiency of an Organic Rankine Cycle (ORC) system. Nine parameters that could impact the ORC's efficiency were examined across nine tests using an orthogonal array. Statistical analysis identified the optimum and worst combinations of parameter levels. The optimum conditions achieved a first law efficiency of 17.3% while the worst was 9.6%. The study provides insights into effective and ineffective ORC parameters and ranks their statistical impact on efficiency.
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Pr (ata)
Graph 3. Variation of power and efficiency with pressure at temperature at 4500C
This document summarizes the results of a sensitivity analysis performed on a heat recovery steam generator (HRSG) for a GE 6FA gas turbine combined cycle power plant. The analysis varied the steam pressure from 40 to 62 atmospheres and steam temperature from 400 to 500 degrees Celsius to determine the optimal operating point. The maximum power and efficiency were achieved at different pressure-temperature combinations, with 58 atmospheres generally providing the best results for temperatures between 450-500 degrees Celsius. Graphs show the relationships between pressure, power, efficiency
This document discusses steam turbine power plant design and cycles. It describes typical steam conditions between 600-1450 psig at 750-950°F for Army power plants. Back pressure turbines exhaust at 250-15 psig and condensing turbines exhaust at 1-5 inches of mercury absolute. Cogeneration plants use back pressure or controlled extraction/condensing cycles to simultaneously produce electric power and steam for heat. The document compares plant heat rates, turbine heat rates, and discusses optimizing steam power plant cycles for maximum efficiency and economy.
This document summarizes a research paper that analyzed heat transfer in an economizer using computational fluid dynamics (CFD). It discussed how fins can be added to economizer tubes to increase the heat transfer surface area between flue gases and boiler feedwater. The document reviewed previous research on economizer design optimization and failures. It described the working of CFD analysis using equations of continuity, momentum, and energy to model fluid flow. The study used the k-ε turbulence model in CFD software to analyze heat transfer with and without fins on an economizer.
Paper design and optimizaton of steam distribution systems for steam power pl...Tony Lewis
This document presents a methodology for optimizing the design of steam distribution networks (SDNs) for steam power plants. The methodology formulates the problem as a mixed-integer nonlinear programming (MINLP) model to minimize total annualized cost. The model determines the optimal structure, configuration, and operation of the SDN as well as its interaction with the heat recovery system. Case studies are used to demonstrate the feasibility and benefits of the proposed simultaneous optimization approach.
The document summarizes an exergy and exergo-economic analysis of the Montazer Ghaem gas turbine power plant in Iran. The analysis finds that the combustion chamber has the highest exergy destruction due to the large temperature difference between the flame and operating fluid. The gas turbine's performance and efficiency are significantly affected by ambient temperature. An increase in ambient temperature decreases the net power output and exergy efficiency. The exergo-economic analysis determines that the combustion chamber also has the largest cost of exergy destruction.
This document proposes a hybrid PID-cascade control system for HVAC systems to improve control performance. It models the heat exchanger and air conditioning space components of an HVAC system. It then designs a hybrid PID-cascade controller that combines traditional PID control with an internal cascade loop. Simulations show the hybrid controller has faster response, better setpoint tracking and disturbance rejection compared to traditional PID, compensator and Ziegler-Nichols tuned PID controllers. The cascade control inner loop improves response speed and precision, while the outer PID loop enhances stability and disturbance rejection for the HVAC system.
The document describes a computational fluid dynamics (CFD) analysis of heat transfer in a rectangular channel with blockages containing elongated holes. A model of the channel was created in design software and meshed before performing CFD simulations. The simulations analyzed how heat transfer coefficients and Nusselt numbers varied with the pitch ratio of the blockages for different Reynolds numbers. Results showed that heat transfer initially increased with pitch ratio up to a value of 6.0, then decreased with further increases, due to changes in flow reattachment. Blockages with shorter holes enhanced heat transfer more but also increased pressure drops more compared to longer holes. The CFD results were also validated against available experimental data, with good agreement.
IRJET- Comparsion of Heat Transfer Analysis of Double Pipe Heat Exchanger wit...IRJET Journal
This document describes an experimental study comparing heat transfer in a double pipe heat exchanger with and without a phase change material (PCM). Cynamide, which melts at 44°C, was used as the PCM. Hot water at 33°C and cold water at 20°C were circulated through the heat exchangers. Temperatures were recorded every 15 minutes. With the PCM, heat transfer increased when its melting temperature was reached, as the PCM absorbed heat during its phase change. The maximum heat transfer and effectiveness occurred in the setup with the PCM pipe, showing around a 20% increase in effectiveness compared to the setup without PCM. Equations for determining the heat transfer rate, maximum
Analysis of Air Conditioning System used in Automobileijtsrd
Air conditioning has great importance in many areas of life. Especially it is crucial in transportation sector. Many people spend long time in an automotive cabin during business, travel, shopping, etc., every day. The aim of this study is to analyze the performance of a bus shell by considering identifying practical solutions in order to reduce the impact of air conditioning on bus, consumption and, therefore, on air pollution. The analysis is carried considering several parameters, including passenger capacity, local climatic conditions, fuel consumptions, and latitude and longitude of starting destination of the places. For the analysis, a bus with passenger capacity of 60 people is selected and then its heat load capacity will be determined by considering different conditions like seasons and various loads. The influence of the refrigerant decrease and the change of the air temperature which gets to exchangers on the refrigeration efficiency of the system to be analyzed. Also, its effectiveness and the power required to drive the compressor will be analyzed. The entire model, its analysis and results are discussed in the below work. Dr. S. Sreenatha Reddy | P. Akhil | N. Raju | K. Vishnu | N. Ashok ""Analysis of Air Conditioning System used in Automobile"" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-3 , April 2019, URL: https://www.ijtsrd.com/papers/ijtsrd23357.pdf
Paper URL: https://www.ijtsrd.com/engineering/mechanical-engineering/23357/analysis-of-air-conditioning-system-used-in-automobile/dr-s-sreenatha-reddy
Using coolant modulation and pre cooling to avoid turbine bladeRakesh Rauth
This document examines methods to prevent turbine blade overheating when firing a gas turbine combined cycle power plant with low calorific value gas. Decreasing the firing temperature can prevent blade overheating but significantly reduces power output. Modulating the coolant supply to each blade row results in a much lower power penalty compared to under-firing. Pre-cooling the coolant before supplying it to the turbine further enhances power output by reducing the required coolant flow. Pre-cooling recovers 80% of the power gain possible from switching to low calorific value gas while providing higher combined cycle efficiency than under-firing.
Model-based adaptive sliding mode control of the subcritical boiler-turbine s...ISA Interchange
As higher requirements are proposed for the load regulation and efficiency enhancement, the control performance of boiler-turbine systems has become much more important. In this paper, a novel robust control approach is proposed to improve the coordinated control performance for subcritical boiler-turbine units. To capture the key features of the boiler-turbine system, a nonlinear control-oriented model is established and validated with the history operation data of a 300 MW unit. To achieve system linearization and decoupling, an adaptive feedback linearization strategy is proposed, which could asymptotically eliminate the linearization error caused by the model uncertainties. Based on the linearized boiler-turbine system, a second-order sliding mode controller is designed with the super-twisting algorithm. Moreover, the closed-loop system is proved robustly stable with respect to uncertainties and disturbances. Simulation results are presented to illustrate the effectiveness of the proposed control scheme, which achieves excellent tracking performance, strong robustness and chattering reduction.
This document presents models of an electric water heater and air conditioner for use in residential demand response strategies. It describes the development of simulation models for these appliances based on their operational and physical characteristics. The models were validated against real measurement data and found to accurately model the appliances, with low errors. The models can provide insight into control strategies to better evaluate performance in residential demand response implementations.
Handbook of mechanical engineering calculationsRoddy Castro
The document discusses several options for boosting the output of a 230 MW combined cycle power plant using a 155 MW gas turbine. It evaluates seven cases: 1) using an evaporative cooler to precool the gas turbine inlet air, 2) using a mechanical chiller, 3) using an absorption chiller, 4) injecting steam into the gas turbine, 5) injecting water into the gas turbine, 6) partially supplementary firing the heat recovery steam generator, and 7) fully supplementary firing the heat recovery steam generator. Case 1 of using an evaporative cooler increased plant output by 6.65 MW and improved heat rate by 15 Btu/kWh, but had a high capital cost of $180/kW.
Robust control of speed and temperature in a power plant gas turbineISA Interchange
In this paper, an H∞ robust controller has been designed for an identified model of MONTAZER GHAEM power plant gas turbine (GE9001E). In design phase, a linear model (ARX model) which is obtained using real data has been applied. Since the turbine has been used in a combined cycle power plant, its speed and also the exhaust gas temperature should be adjusted simultaneously by controlling fuel signals and compressor inlet guide vane (IGV) position. Considering the limitations on the system inputs, the aim of the control is to maintain the turbine speed and the exhaust gas temperature within desired interval under uncertainties and load demand disturbances. Simulation results of applying the proposed robust controller on the nonlinear model of the system (NARX model), fairly fulfilled the predefined aims. Simulations also show the improvement in the performance compared to MPC and PID controllers for the same conditions.
IRJET- Optimization and CFD Analysis on Profile Elements of Regenerative Rota...IRJET Journal
This document discusses the optimization and computational fluid dynamics (CFD) analysis of different profile elements in a regenerative rotary air preheater. It begins with an introduction to rotary air preheaters and describes the various profile types used as heat transfer elements. Experimental measurements from a coal-fired power plant are presented. CFD models of five profile elements are analyzed to determine their outlet air and flue gas temperatures. The results show that the advanced clear element profile provides the best performance with higher air outlet temperature and lower flue gas outlet temperature compared to other profiles.
Nonlinear multivariable control and performance analysis of an air-handling unitAli Abedi
This document summarizes a study that investigates nonlinear control approaches for an air-handling unit (AHU). A nonlinear multi-input multi-output dynamic model of an AHU is developed. Both indoor temperature and relative humidity are controlled by manipulating air and cold water flow rates. Two nonlinear control approaches, gain scheduling and feedback linearization, are designed and compared. Results show feedback linearization achieves faster tracking of setpoints but with more overshoot, while gain scheduling has less oscillation in control inputs and likely lower energy use. Feedback linearization is also more robust to model parameter uncertainty.
Analysis of Process Parameters to Improve Power Plant EfficiencyIOSRJMCE
This research paper analyses the operational parameters of a thermal power plant to improve effectively & efficient running of the machine while ensuring a degree of compliance with statutory regulations. This study aims to identify the operational gaps associated with running operational parameter in power plant process. It is focused to detect a different thermodynamic variable involved, being multivariate and automatic. For variation of each one of this operational parameters, performance calculations are find out to configure a database of energy variation. The variable data sets now can be used as assessment criteria based on detecting deviations from a reference system that has been updated during plant-performance tests. Although the most important outcome is the highly precise and valuable information that will be obtained on the live operating mode, leading to a head improvements in the cycle efficiency and achieved in the overall control system of the thermal plant. The main aim is to detect any abnormality, reacting as quickly as possible to return the plant to a normal operation mode at best efficient manner.
The document summarizes the development of a new library called Ship Energy Systems for simulating and optimizing ship machinery systems. The library allows modeling of engines, generators, cooling systems and other auxiliary components. It facilitates variant analysis to optimize energy efficiency and quantify potential fuel savings. An example model of a medium-sized freight vessel is presented to demonstrate the library's capabilities. The library reduces the time needed for ship energy simulations compared to developing models from scratch.
A practical approach to design and optimization of single phase liquid to liq...iaemedu
The document describes the design and optimization of a shell and tube heat exchanger. It presents a method based on Tinker's approach that incorporates modifications from Kern and Kakac. A 17-step thermal design procedure is outlined that involves sizing the heat exchanger dimensions and components through an iterative process to meet a specified heat load. A computer program was developed to automate the calculations and optimize the design in a more efficient manner than manual calculations. The program allows the user to input parameters and obtain an optimized design solution.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
The document summarizes an energy audit conducted on a thermal power plant in Jordan. The power plant produces 14.36 MW through a Rankine cycle using natural gas. A preliminary energy audit evaluated the performance of the plant's components, including the boiler, turbine, condenser, and pumps. The results showed deviations in efficiency for all components compared to their design specifications. Specifically, the boiler had the largest deviation of 4.9% efficiency, likely due to poor water and fuel quality and heat loss. Several solutions were proposed to improve the plant's efficiency.
Optimization of Organic Rankine Cycle’s thermal efficiency based on Grey rela...IRJET Journal
This document summarizes a study that used the Taguchi method and grey relational analysis to optimize the thermal efficiency of an Organic Rankine Cycle (ORC) system. Nine parameters that could impact the ORC's efficiency were examined across nine tests using an orthogonal array. Statistical analysis identified the optimum and worst combinations of parameter levels. The optimum conditions achieved a first law efficiency of 17.3% while the worst was 9.6%. The study provides insights into effective and ineffective ORC parameters and ranks their statistical impact on efficiency.
A Review of Computational Fluid Dynamics Analysis of Cylinder Head Water Jack...IRJET Journal
This document summarizes a computational fluid dynamics (CFD) analysis of the cylinder head water jacket of a diesel engine. The study aims to analyze heat transfer and fluid flow within the existing cooling jacket design. The cylinder head geometry is modeled in CATIA and CFD analysis is performed in ANSYS Fluent to investigate factors affecting cooling performance. Parameters will be optimized and validated against previous research to improve cooling performance through modifications to the jacket design and coolant mixture proportions.
1 ijebm jan-2018-1-combustion adjustment in a naturalAI Publications
Shortage of detailed and accurate experimental data on fuel-air mixing in furnaces is due to the difficulty and complexity of measurements in flames. Although it may be possible with infra-Red camera to obtain an indication of what happens in the furnace by graphical image resolution this is not expected to be sufficiently detailed because it contains only the temperature gradient. More detailed information, however, may be obtained from the simulated resolution using Computational Fluid Dynamics (CFD) technique where the total number of elements/points defines the detailed level that can be displayed or captured in graphical image. Simulation resolution studies two aspects of the momentum effects on flame which are the forward momentum normally associated with the average outlet velocity of the combustion products and the lateral momentum caused by swirl. Following the American Petroleum Institute guidelines (API 560) for combustion adjustment in furnaces, it may be possible to have less emission and a maximum efficiency, but the potential interaction between the several operation and design factors are not thereby considered as in a mathematical model of CFD.
OPTIMIZATION OF AN OPEN CYCLE GAS TURBINE POWER PLANT USING EXERGOECONOMICSijmech
The purpose of current study is to analyze the performance of an open cycle gas turbine power plant using
the concepts of exergoeconomics. Exergoeconomic technique involves the use of Second law of
thermodynamics and assigns monetary values to the thermodynamic quantity known as exergy. Analyses
based on exergoeconomic criteria are done for the open cycle gas turbine power plant turbine. The
methodology is illustrated using the example of a 25 MW open cycle gas turbine power plant. Optimization
has been done for the open cycle gas turbine power plant as tradeoffs between the unit product cost of the
compressor and combustion chamber as functions of compressor pressure ratio and unit product costs of
combustion chamber and gas turbine as functions of turbine inlet temperature.
This document summarizes a study that performed a life assessment of a fighter jet engine annular combustor liner using a combined fluid/structural approach. Computational fluid dynamics analyses were conducted to obtain the thermal loading on the combustor liner from the combustion process. Finite element analyses were then performed to calculate the resulting temperature and stress/strain distributions in the liner. A method was developed to analyze a complete measured flight profile with limited computational effort. The creep and fatigue life for a measured flight were calculated and compared to field experience data. While the exact number of cycles to crack initiation was difficult to predict, the locations and directions of cracking correlated well with field data.
IRJET- Parametric Study on Radiator Test RigIRJET Journal
The document describes a parametric study conducted on a radiator test rig. The test rig was designed to test the performance of radiators under various air and hot water flow rate conditions. It consists of an automobile radiator, cooling fan, water pump, reservoirs, and temperature sensors. Experiments were conducted by heating the water in the reservoir and passing it through the radiator while varying the water and air flow rates. Inlet and outlet temperatures were measured and used to evaluate the heat transfer performance of the radiator. The rig allows for easy measurement of temperatures and compact, low-cost testing of radiators.
IRJET - Performance Evaluation and Parametric Study of Basic and Reheated Coo...IRJET Journal
This document discusses the performance evaluation and parametric study of basic and reheated cooled gas turbine cycles using exergy analysis. It presents schematic diagrams of the basic and reheated gas turbine cycles with air film blade cooling. Governing equations for modeling the cycle components are provided. Results from a MATLAB simulation show that for both cycles, coolant mass flow rate increases with increasing turbine inlet temperature and compressor pressure ratio. Exergy efficiency decreases with increasing turbine inlet temperature but increases with increasing pressure ratio. The basic cooled gas turbine cycle has higher exergy efficiency than the reheated cycle when the turbine inlet temperature is 1800K and pressure ratio is 30.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
IRJET- Performance Evaluation of Automobile RadiatorIRJET Journal
This document discusses performance evaluation of automobile radiators. It begins with an abstract that outlines the goal of studying and analyzing the thermal behavior of automobile radiators using the LMTD and ε-NTU methods. It then provides background on radiators and their role in removing waste heat from engines. The literature review summarizes previous studies on optimizing radiator design parameters like tube pitch and airflow velocity. The problem statement discusses the need to improve radiator performance as engines have become more powerful. The experimental scheme and design parameters sections outline the planned study to evaluate radiator prototypes using different parameters. In conclusions, the work aims to enhance radiator performance by altering convective heat transfer coefficients and provide easier radiator design using case
IRJET- Performance and Evaluation of Aqua Ammonia Air Conditioner System ...IRJET Journal
This document discusses the performance evaluation of an aqua-ammonia air conditioning system for automobiles that uses waste exhaust heat from the vehicle engine. The study examines how the generator and absorption refrigeration system can utilize the available waste heat. Results found that the cooling capacity was affected by the ammonia concentration and provided acceptable cooling between 1-1.5 tons. The coefficient of performance was highest at higher generator and evaporator temperatures but decreased with increasing condenser and absorber temperatures. Overall, the study shows that an aqua-ammonia vapor absorption system has the potential to provide air conditioning for vehicles using only waste exhaust heat from the engine.
Exergy analysis of inlet water temperature of condenserIJERA Editor
The most of the power plant designed by energetic performance criteria based on first law of thermodynamics. According to First law of thermodynamics energy analysis cannot be justified the losses of energy.The method of exergy analysis is well suited to describe true magnitude of waste and loss to be determined. Such information can be used in the design of new energy efficient system and increasing the efficiency of existing systems.In the present study exergy analysis of the shell and tube condenser is carried out. As the condenser is one of the major components of the power plant, so it is necessary to operate the condenser efficiently under the various operating condition to increase the overall efficiency of the power plant. In the present study inlet temperature of the condenser is optimized using the exergy method. The main aim of paper is to be find out causes of energy destruction that can be helpful to redesign the system and to increase the efficiency
This document summarizes the modeling, identification, and control of a 162MW heavy duty industrial gas turbine. It describes using Rowen's model and a neural network model to model the mechanical behavior and system identification of the gas turbine. The control rules are applied to both models and their results are compared. Rowen's model is a commonly used simplified model for gas turbines, while the neural network model identifies the system using input-output data. The document evaluates and compares the performance of the two models.
ESTIMATION AND ANALYSIS OF CYCLE EFFICIENCY FOR SHELL AND TUBE HEAT EXCHANGER...IAEME Publication
Shell and tube Heat exchanger (STHE) is one of the most common and widely used energy transporter suited for domestic usages as well as industrial applications. In this paper, we consider shell and tube heat exchanger as a device with known input and output parameters. This work utilizes imperative design constraints like tube configuration, fluids, surface and temperature (constant magnitude) as input parameters and energetic cycle efficiency considered as desired output parameter depicting performance of the device. The model was trained and tested by proposed Genetic algorithm (GA) technique. This entire computational procedure is implemented in MATLAB platform.
Analysis of recoverable exhaust energy from a light duty gasoline engine by u...ijctet
This document reviews methods of recovering exhaust energy from internal combustion engines using heat pipes. It discusses how heat pipes effectively transfer heat from exhaust gases to a condenser region, enhancing engine thermal performance. The document examines several studies on recovering exhaust waste heat using Rankine cycle systems and heat pipes. These studies found that waste heat recovery can increase engine fuel efficiency by 3-34% and power output by up to 20%, depending on the system and engine operating conditions. Recovering just 6% of exhaust heat energy could result in a 10% reduction in fuel consumption. The document concludes that heat pipe waste heat recovery systems show promising potential but require further research.
Design of Heat Exchanger Network for VCM Distillation Unit Using Pinch Techno...IJERA Editor
In process industries, heat exchanger networks represent an important part of the plant structure. The purpose of the networks is to maximize heat recovery, thereby lowering the overall plant costs. In process industries, during operation of any heat exchanger network (HEN), the major aim is to focus on the best performance of the network As in present condition of fuel crises is one of the major problem faced by many country & industrial utility is majorly depend on this. There is technique called process integration which is used for integrate heat within loop so optimize the given process and minimize the heating load and cooling load .In the present study of heat integration on VCM (vinyl chloride monomer) distillation unit, Heat exchanger network (HEN) is designed by using Aspen energy analyzer V8.0 software. This software implements a methodology for HEN synthesis with the use of pinch technology. Several heat integration networks are designed with different ΔT min and total annualized cost compared to obtain the optimal design. The network with a ΔT min of 90C is the most optimal where the largest energy savings are obtained with the appropriate use of utilities (Save 15.3764% for hot utilities and 47.52% for cold utilities compared with the current plant configuration). Percentage reduction in total operating cost is 18.333%. From calculation Payback Period for new design is 3.15 year. This save could be done through a plant revamp, with the addition of two heat exchangers. This improvement are done in the process associated with this technique are not due to the use of advance unit operation, but to the generation of heat integration scheme. The Pinch Design Method can be employed to give good designs in rapid time and with minimum data.
PERFORMANCE ANALYSIS OF A COMBINED CYCLE GAS TURBINE UNDER VARYING OPERATING ...meijjournal
The combined cycle gas turbine integrates the Brayton cycle as topping cycle and the steam turbine
Rankine cycle as bottoming cycle in order to achieve higher thermal efficiency and proper utilization of
energy by minimizing the energy loss to a minimum. In this work, the effect of various operating
parameters such as maximum temperature and pressure of Rankine cycle, turbine inlet temperature and
pressure ratio of Brayton cycle on the net output work and thermal efficiency of the combine cycle are
investigated. The outcome of this work can be utilized in order to facilitate the design of a combined cycle
with higher efficiency and output work. A MATLAB simulation has been carried out to study the effects and
influences of the above mentioned parameters on the efficiency and work output.
IRJET- Fatigue Life Estimation of Turbine Bypass ValveIRJET Journal
This document discusses the fatigue life estimation of a turbine bypass valve. It begins with an introduction to turbine bypass systems and their importance in protecting power plant components during transient operations. It then describes the methodology used, which includes finite element modeling of the valve, transient thermal analysis to determine temperature distributions, structural analysis to determine stresses, and estimation of fatigue life using standards. The results section shows the thermal analysis results at various time steps, indicating the highest stresses occur near locations of maximum thermal gradients. Finally, it concludes that fatigue life is highly dependent on thermal behavior and a non-linear transient thermal analysis is needed to apply thermal and mechanical loads for life estimation. The preheating temperature was found to be 350°C to achieve a damage index
Analysis of turbocharger performance for jet assisted vertical takeoff and la...Ijrdt Journal
This paper gives a brief analysis on the performance parameters of a Turbocharger, by fabricating a separate combustion chamber and mocking the working of a jet engine. Parameters such as variation of specific heat, dimensionless flow parameters, variation of turbulence, conductivity, thrust developed etc are studied using simulation of the model, and compared with the actual working of the prototype. It can be conveniently proposed from the experiment that turbocharger can be used effectively for developing vertical take-off assist.
Similar to An approach to evaluate the heat exchanger retrofit for installed industrial gas turbines part i – technical evaluation (20)
Mechanical properties of hybrid fiber reinforced concrete for pavementseSAT Journals
Abstract
The effect of addition of mono fibers and hybrid fibers on the mechanical properties of concrete mixture is studied in the present
investigation. Steel fibers of 1% and polypropylene fibers 0.036% were added individually to the concrete mixture as mono fibers and
then they were added together to form a hybrid fiber reinforced concrete. Mechanical properties such as compressive, split tensile and
flexural strength were determined. The results show that hybrid fibers improve the compressive strength marginally as compared to
mono fibers. Whereas, hybridization improves split tensile strength and flexural strength noticeably.
Keywords:-Hybridization, mono fibers, steel fiber, polypropylene fiber, Improvement in mechanical properties.
Material management in construction – a case studyeSAT Journals
Abstract
The objective of the present study is to understand about all the problems occurring in the company because of improper application
of material management. In construction project operation, often there is a project cost variance in terms of the material, equipments,
manpower, subcontractor, overhead cost, and general condition. Material is the main component in construction projects. Therefore,
if the material management is not properly managed it will create a project cost variance. Project cost can be controlled by taking
corrective actions towards the cost variance. Therefore a methodology is used to diagnose and evaluate the procurement process
involved in material management and launch a continuous improvement was developed and applied. A thorough study was carried
out along with study of cases, surveys and interviews to professionals involved in this area. As a result, a methodology for diagnosis
and improvement was proposed and tested in selected projects. The results obtained show that the main problem of procurement is
related to schedule delays and lack of specified quality for the project. To prevent this situation it is often necessary to dedicate
important resources like money, personnel, time, etc. To monitor and control the process. A great potential for improvement was
detected if state of the art technologies such as, electronic mail, electronic data interchange (EDI), and analysis were applied to the
procurement process. These helped to eliminate the root causes for many types of problems that were detected.
Managing drought short term strategies in semi arid regions a case studyeSAT Journals
Abstract
Drought management needs multidisciplinary action. Interdisciplinary efforts among the experts in various fields of the droughts
prone areas are helpful to achieve tangible and permanent solution for this recurring problem. The Gulbarga district having the total
area around 16, 240 sq.km, and accounts 8.45 per cent of the Karnataka state area. The district has been situated with latitude 17º 19'
60" North and longitude of 76 º 49' 60" east. The district is situated entirely on the Deccan plateau positioned at a height of 300 to
750 m above MSL. Sub-tropical, semi-arid type is one among the drought prone districts of Karnataka State. The drought
management is very important for a district like Gulbarga. In this paper various short term strategies are discussed to mitigate the
drought condition in the district.
Keywords: Drought, South-West monsoon, Semi-Arid, Rainfall, Strategies etc.
Life cycle cost analysis of overlay for an urban road in bangaloreeSAT Journals
Abstract
Pavements are subjected to severe condition of stresses and weathering effects from the day they are constructed and opened to traffic
mainly due to its fatigue behavior and environmental effects. Therefore, pavement rehabilitation is one of the most important
components of entire road systems. This paper highlights the design of concrete pavement with added mono fibers like polypropylene,
steel and hybrid fibres for a widened portion of existing concrete pavement and various overlay alternatives for an existing
bituminous pavement in an urban road in Bangalore. Along with this, Life cycle cost analyses at these sections are done by Net
Present Value (NPV) method to identify the most feasible option. The results show that though the initial cost of construction of
concrete overlay is high, over a period of time it prove to be better than the bituminous overlay considering the whole life cycle cost.
The economic analysis also indicates that, out of the three fibre options, hybrid reinforced concrete would be economical without
compromising the performance of the pavement.
Keywords: - Fatigue, Life cycle cost analysis, Net Present Value method, Overlay, Rehabilitation
Laboratory studies of dense bituminous mixes ii with reclaimed asphalt materialseSAT Journals
Abstract
The issue of growing demand on our nation’s roadways over that past couple of decades, decreasing budgetary funds, and the need to
provide a safe, efficient, and cost effective roadway system has led to a dramatic increase in the need to rehabilitate our existing
pavements and the issue of building sustainable road infrastructure in India. With these emergency of the mentioned needs and this
are today’s burning issue and has become the purpose of the study.
In the present study, the samples of existing bituminous layer materials were collected from NH-48(Devahalli to Hassan) site.The
mixtures were designed by Marshall Method as per Asphalt institute (MS-II) at 20% and 30% Reclaimed Asphalt Pavement (RAP).
RAP material was blended with virgin aggregate such that all specimens tested for the, Dense Bituminous Macadam-II (DBM-II)
gradation as per Ministry of Roads, Transport, and Highways (MoRT&H) and cost analysis were carried out to know the economics.
Laboratory results and analysis showed the use of recycled materials showed significant variability in Marshall Stability, and the
variability increased with the increase in RAP content. The saving can be realized from utilization of recycled materials as per the
methodology, the reduction in the total cost is 19%, 30%, comparing with the virgin mixes.
Keywords: Reclaimed Asphalt Pavement, Marshall Stability, MS-II, Dense Bituminous Macadam-II
Laboratory investigation of expansive soil stabilized with natural inorganic ...eSAT Journals
This document summarizes a study on stabilizing expansive black cotton soil with the natural inorganic stabilizer RBI-81. Laboratory tests were conducted to evaluate the effect of RBI-81 on the soil's engineering properties. The tests showed that with 2% RBI-81 and 28 days of curing, the unconfined compressive strength increased by around 250% and the CBR value improved by approximately 400% compared to the untreated soil. Overall, the study found that RBI-81 effectively improved the strength properties of the black cotton soil and its suitability as a soil stabilizer was supported.
Influence of reinforcement on the behavior of hollow concrete block masonry p...eSAT Journals
Abstract
Reinforced masonry was developed to exploit the strength potential of masonry and to solve its lack of tensile strength. Experimental
and analytical studies have been carried out to investigate the effect of reinforcement on the behavior of hollow concrete block
masonry prisms under compression and to predict ultimate failure compressive strength. In the numerical program, three dimensional
non-linear finite elements (FE) model based on the micro-modeling approach is developed for both unreinforced and reinforced
masonry prisms using ANSYS (14.5). The proposed FE model uses multi-linear stress-strain relationships to model the non-linear
behavior of hollow concrete block, mortar, and grout. Willam-Warnke’s five parameter failure theory has been adopted to model the
failure of masonry materials. The comparison of the numerical and experimental results indicates that the FE models can successfully
capture the highly nonlinear behavior of the physical specimens and accurately predict their strength and failure mechanisms.
Keywords: Structural masonry, Hollow concrete block prism, grout, Compression failure, Finite element method,
Numerical modeling.
Influence of compaction energy on soil stabilized with chemical stabilizereSAT Journals
This document summarizes a study on the influence of compaction energy on soil stabilized with a chemical stabilizer. Laboratory tests were conducted on locally available loamy soil treated with a patented polymer liquid stabilizer and compacted at four different energy levels. The study found that increasing the compaction effort increased the density of both untreated and treated soil, but the rate of increase was lower for stabilized soil. Treating the soil with the stabilizer improved its unconfined compressive strength and resilient modulus, and reduced accumulated plastic strain, with these properties further improved by higher compaction efforts. The stabilized soil exhibited strength and performance benefits compared to the untreated soil.
Geographical information system (gis) for water resources managementeSAT Journals
This document describes a hydrological framework developed in the form of a Hydrologic Information System (HIS) to meet the information needs of various government departments related to water management in a state. The HIS consists of a hydrological database coupled with tools for collecting and analyzing spatial and non-spatial water resources data. It also incorporates a hydrological model to indirectly assess water balance components over space and time. A web-based GIS portal was created to allow users to access and visualize the hydrological data, as well as outputs from the SWAT hydrological model. The framework is intended to facilitate integrated water resources planning and management across different administrative levels.
Forest type mapping of bidar forest division, karnataka using geoinformatics ...eSAT Journals
Abstract
The study demonstrate the potentiality of satellite remote sensing technique for the generation of baseline information on forest types
including tree plantation details in Bidar forest division, Karnataka covering an area of 5814.60Sq.Kms. The Total Area of Bidar
forest division is 5814Sq.Kms analysis of the satellite data in the study area reveals that about 84% of the total area is Covered by
crop land, 1.778% of the area is covered by dry deciduous forest, 1.38 % of mixed plantation, which is very threatening to the
environmental stability of the forest, future plantation site has been mapped. With the use of latest Geo-informatics technology proper
and exact condition of the trees can be observed and necessary precautions can be taken for future plantation works in an appropriate
manner
Keywords:-RS, GIS, GPS, Forest Type, Tree Plantation
Factors influencing compressive strength of geopolymer concreteeSAT Journals
Abstract
To study effects of several factors on the properties of fly ash based geopolymer concrete on the compressive strength and also the
cost comparison with the normal concrete. The test variables were molarities of sodium hydroxide(NaOH) 8M,14M and 16M, ratio of
NaOH to sodium silicate (Na2SiO3) 1, 1.5, 2 and 2.5, alkaline liquid to fly ash ratio 0.35 and 0.40 and replacement of water in
Na2SiO3 solution by 10%, 20% and 30% were used in the present study. The test results indicated that the highest compressive
strength 54 MPa was observed for 16M of NaOH, ratio of NaOH to Na2SiO3 2.5 and alkaline liquid to fly ash ratio of 0.35. Lowest
compressive strength of 27 MPa was observed for 8M of NaOH, ratio of NaOH to Na2SiO3 is 1 and alkaline liquid to fly ash ratio of
0.40. Alkaline liquid to fly ash ratio of 0.35, water replacement of 10% and 30% for 8 and 16 molarity of NaOH and has resulted in
compressive strength of 36 MPa and 20 MPa respectively. Superplasticiser dosage of 2 % by weight of fly ash has given higher
strength in all cases.
Keywords: compressive strength, alkaline liquid, fly ash
Experimental investigation on circular hollow steel columns in filled with li...eSAT Journals
Abstract
Composite Circular hollow Steel tubes with and without GFRP infill for three different grades of Light weight concrete are tested for
ultimate load capacity and axial shortening , under Cyclic loading. Steel tubes are compared for different lengths, cross sections and
thickness. Specimens were tested separately after adopting Taguchi’s L9 (Latin Squares) Orthogonal array in order to save the initial
experimental cost on number of specimens and experimental duration. Analysis was carried out using ANN (Artificial Neural
Network) technique with the assistance of Mini Tab- a statistical soft tool. Comparison for predicted, experimental & ANN output is
obtained from linear regression plots. From this research study, it can be concluded that *Cross sectional area of steel tube has most
significant effect on ultimate load carrying capacity, *as length of steel tube increased- load carrying capacity decreased & *ANN
modeling predicted acceptable results. Thus ANN tool can be utilized for predicting ultimate load carrying capacity for composite
columns.
Keywords: Light weight concrete, GFRP, Artificial Neural Network, Linear Regression, Back propagation, orthogonal
Array, Latin Squares
Experimental behavior of circular hsscfrc filled steel tubular columns under ...eSAT Journals
This document summarizes an experimental study that tested circular concrete-filled steel tube columns with varying parameters. 45 specimens were tested with different fiber percentages (0-2%), tube diameter-to-wall-thickness ratios (D/t from 15-25), and length-to-diameter (L/d) ratios (from 2.97-7.04). The results found that columns filled with fiber-reinforced concrete exhibited higher stiffness, equal ductility, and enhanced energy absorption compared to those filled with plain concrete. The load carrying capacity increased with fiber content up to 1.5% but not at 2.0%. The analytical predictions of failure load closely matched the experimental values.
Evaluation of punching shear in flat slabseSAT Journals
Abstract
Flat-slab construction has been widely used in construction today because of many advantages that it offers. The basic philosophy in
the design of flat slab is to consider only gravity forces; this method ignores the effect of punching shear due to unbalanced moments
at the slab column junction which is critical. An attempt has been made to generate generalized design sheets which accounts both
punching shear due to gravity loads and unbalanced moments for cases (a) interior column; (b) edge column (bending perpendicular
to shorter edge); (c) edge column (bending parallel to shorter edge); (d) corner column. These design sheets are prepared as per
codal provisions of IS 456-2000. These design sheets will be helpful in calculating the shear reinforcement to be provided at the
critical section which is ignored in many design offices. Apart from its usefulness in evaluating punching shear and the necessary
shear reinforcement, the design sheets developed will enable the designer to fix the depth of flat slab during the initial phase of the
design.
Keywords: Flat slabs, punching shear, unbalanced moment.
Evaluation of performance of intake tower dam for recent earthquake in indiaeSAT Journals
Abstract
Intake towers are typically tall, hollow, reinforced concrete structures and form entrance to reservoir outlet works. A parametric
study on dynamic behavior of circular cylindrical towers can be carried out to study the effect of depth of submergence, wall thickness
and slenderness ratio, and also effect on tower considering dynamic analysis for time history function of different soil condition and
by Goyal and Chopra accounting interaction effects of added hydrodynamic mass of surrounding and inside water in intake tower of
dam
Key words: Hydrodynamic mass, Depth of submergence, Reservoir, Time history analysis,
Evaluation of operational efficiency of urban road network using travel time ...eSAT Journals
This document evaluates the operational efficiency of an urban road network in Tiruchirappalli, India using travel time reliability measures. Traffic volume and travel times were collected using video data from 8-10 AM on various roads. Average travel times, 95th percentile travel times, and buffer time indexes were calculated to assess reliability. Non-motorized vehicles were found to most impact reliability on one road. A relationship between buffer time index and traffic volume was developed. Finally, a travel time model was created and validated based on length, speed, and volume.
Estimation of surface runoff in nallur amanikere watershed using scs cn methodeSAT Journals
Abstract
The development of watershed aims at productive utilization of all the available natural resources in the entire area extending from
ridge line to stream outlet. The per capita availability of land for cultivation has been decreasing over the years. Therefore, water and
the related land resources must be developed, utilized and managed in an integrated and comprehensive manner. Remote sensing and
GIS techniques are being increasingly used for planning, management and development of natural resources. The study area, Nallur
Amanikere watershed geographically lies between 110 38’ and 110 52’ N latitude and 760 30’ and 760 50’ E longitude with an area of
415.68 Sq. km. The thematic layers such as land use/land cover and soil maps were derived from remotely sensed data and overlayed
through ArcGIS software to assign the curve number on polygon wise. The daily rainfall data of six rain gauge stations in and around
the watershed (2001-2011) was used to estimate the daily runoff from the watershed using Soil Conservation Service - Curve Number
(SCS-CN) method. The runoff estimated from the SCS-CN model was then used to know the variation of runoff potential with different
land use/land cover and with different soil conditions.
Keywords: Watershed, Nallur watershed, Surface runoff, Rainfall-Runoff, SCS-CN, Remote Sensing, GIS.
Estimation of morphometric parameters and runoff using rs & gis techniqueseSAT Journals
This document summarizes a study that used remote sensing and GIS techniques to estimate morphometric parameters and runoff for the Yagachi catchment area in India over a 10-year period. Morphometric analysis was conducted to understand the hydrological response at the micro-watershed level. Daily runoff was estimated using the SCS curve number model. The results showed a positive correlation between rainfall and runoff. Land use/land cover changes between 2001-2010 were found to impact estimated runoff amounts. Remote sensing approaches provided an effective means to model runoff for this large, ungauged area.
Effect of variation of plastic hinge length on the results of non linear anal...eSAT Journals
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An approach to evaluate the heat exchanger retrofit for installed industrial gas turbines part i – technical evaluation
1. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
_______________________________________________________________________________________
Volume: 04 Issue: 09 | September-2015, Available @ http://www.ijret.org 1
AN APPROACH TO EVALUATE THE HEAT EXCHANGER RETROFIT
FOR INSTALLED INDUSTRIAL GAS TURBINES: PART I –
TECHNICAL EVALUATION
Waleed Al-Busaidi1
, Pericles Pilidis2
1
Researcher in Cranfield University;School of Aerospace, Transport and Manufacturing; Bedfordshire; UK
2
Head of Propulsion Engineering Centre, Cranfield University, Bedfordshire, UK
Abstract
This paper is the first part of a two-part study aiming to introduce a new integrated approach to evaluate the techno-economic
value of recuperator retrofit on existing gas turbine engines. The original gas turbines are designed for combined cycles so that
the pressure ratios are moderate to secure suitable exhaust temperatures. One way to enhance the thermal efficiency of some gas
turbines is by using recuperation to recover some of the exhaust heat. In this part, the developed model is described and
implemented for two gas turbine engines so the obtained characteristics are evaluated against the actual data. The new approach
will assist users to select the suitable gas turbine models with favorable recuperator characteristics based on a technical and
economic prospective. Besides, the performance results are used to design an appropriate shell and tube heat exchanger.
Moreover, a new technique has been established to define the typical heat exchanger parameters in order to ensure the highest
possible improvements over the original cycles. One of the main features of this method is that it depends only on the velocity of
hot and cold heat exchanger streams from which the rest of the heat exchanger design and performance characteristics were
derived.
Key Words: integrated approach, techno-economic value, recuperation, shell and tube heat exchanger, velocity
--------------------------------------------------------------------***----------------------------------------------------------------------
1. INTRODUCTION
Many existing power generation installations are based on
moderate pressure ratio gas turbines where the exhaust gas
temperature (EGT) is greater than the compressor discharge
temperature(CDT). This makes the provision of a heat
transfer process attractive [1]. Besides, the low fuel
consumption has been one of the critical features to select a
gas turbine for power generation due to the gradual increase
in the fuel cost. One way to enhance this efficiency is by
using the recuperation to recover some of the exhausted heat
which normally exceeds 50% of the total produced energy
instead of injecting it into the atmosphere.
The main function of gas turbine heat exchangers is to
enable the heat transfer fromthe hot streamcoming from the
turbine exhaust to the cold stream which is the discharge
compressor air. The actual amount of heat transfer between
the recuperator streams can be determined by the following
equation.
𝑄 𝑎𝑐𝑡 = 𝑊 𝐶 𝑃, 𝑇1 − 𝑇2 = 𝑊𝑐 𝐶 𝑃,𝐶 𝑇𝑐2 − 𝑇𝑐1 (1)
The desired characteristics of a heat exchanger are: high
effectiveness, low pressure drop, low manufacturing and
operating costs and low physical weight and size. The
importance of each of these features depends on the type of
application [2]. Unfortunately, there is a conflict between
some of these design characteristics so to design a heat
exchanger with a higher effectiveness, a larger recuperator
size is required which should be considered in terms of the
available space and maximum allowed weight in some
applications. Furthermore, the price of the heat exchanger is
strongly influenced by its size so as recuperator size
increases, the price will also increase. Consequently, the
selected features of the heat exchanger have to be optimized
and a compromise has to be performed to select the
appropriate characteristics based on the application
requirements.
Unfortunately, there is no available systematic approach in
the open literature to define the optimum cycle parameters
and typical heat exchanger characteristics for higher techno-
economic value. Hence, this study aims to introduce a new
approach to determine the optimum heat exchanger
characteristics in order to attain the highest possible
technical and economical values. One of the unique features
of the developed method is that that it basically depends on
the flow velocity to derive the rest of parameters. This
model has been implemented with two installed gas turbine
models and an optimization process is conducted to select
the design parameters of the heat exchanger.
This paper is organized into three main sections. The first
part presents some backgrounds for the developed method
followed by the detailed description of the used
methodology and empirical correlations. The second part
demonstrates the obtained heat exchanger and overall cycle
characteristics using the derived approach for both gas
turbines. Finally, a sensitivity study is performed to evaluate
2. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
_______________________________________________________________________________________
Volume: 04 Issue: 09 | September-2015, Available @ http://www.ijret.org 2
the suction parameters effects on the overall recuperative
gas turbine cycle.
2. HEAT EXCHANGER EVELUATION
METHODOLOGY
This part of the study describes the technical evaluation of
the heat exchanger features for gas turbine retrofit. This
example will be a useful illustration of how to optimize
recuperator characteristics for better cycle performance.
The performance of the gas turbines is simulated and the
isentropic efficiencies, pressure losses and bleed air are
assumed in order to match the performance of the simulated
models with the original specifications provided by the
supplier. The calculated discharge compressor conditions
and the turbine exhaust parameters are used as input features
of both cold and hot streams respectively.
The designed heat exchanger is from shell and tube type
which is used widely in process industry. In general, the
high-pressure stream is typically directed through the tubes
while the other stream flows in the space between the tubes
and the outer shell. The tube geometry parameters are
assumed at the beginning and then modified to obtain the
allowed pressure drop in the cold side. Besides, the required
duty is calculated using both Log Mean Temperature
Difference and Number of Transfer Units methods. The
overall heat transfer coefficient (U) is assumed and it is
iterated at the end until both values are equal.
The inside heat transfer coefficient is assumed and then it
will be calculated based on Reynolds number and tube
geometry. The assumed value is iterated to be equal to the
final calculated coefficient. Moreover, the shell geometry
dimensions are specified based on the recommended values
of the shell design parameters and the allowed pressure drop
in the hot side.There are different methods that have been
developed to calculate the heat transfer coefficient and
pressure drop of shell side, the Bell-Delaware method has
been used in this paper.
Figure 1: Basic Component of Shell and Tube Heat
Exchanger
Figure 2: Basic Component of Simulated Simple and
Recuperative Engine Cycles
Figure 3: A Strategy to Choose the Pressure Drop and Heat
Transfer
3. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
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Volume: 04 Issue: 09 | September-2015, Available @ http://www.ijret.org 3
Figure 4: Flow Diagram of the Developed Approach
The size and weight of the recuperator are calculated based
on the selected design parameters which can be iterated to
obtain the allowed recuperator size and weight when the
space and weight are critical.
In general, the geometrical parameters of the recuperator
have been selected to satisfy the required duty and in order
to meet the expected effectiveness and pressure drops of
both sides. Figure 3 illustrates the design parameters that
can be adjusted to control the required heat transfer duty and
pressure drops. This is used to optimize the optimal
recuperator characteristics according to the derived features
and the impact on the overall recuperative cycle.
An important feature of the developed methodology is its
dependency on the inlet flow velocity of the recuperator to
obtain the geometrical features of the installed heat
exchanger and the overall performance parameters of the
recuperative cycle.
𝜂, 𝑃𝑆, 𝑃, 𝑁𝑃𝑉, ∆𝑝, 𝑤 = 𝑓(𝑣1𝑐 , 𝑣1 )
(2)
In this paper, a technical evaluation is conducted to decide
the typical heat exchanger features which will be assessed
economically in the second part of this study
3. DEVELOPED APPROACHDESCRIPTION
3.1 Engine Selection Technique
When there are several existing gas turbines models
operating in the field, the right selection for the engine is
essential to achieve the highest possible improvement in the
performance. In this study, three main criteria will be used
to evalute the simple cycle gas turbines performance which
are:
Difference between the compressor discharge temperature
(CDT) and exhaust gas temperature (EGT)
Available installation space.
Thermal efficiency of original operating gas tubine cycle.
The thermla efficiency of gas turbine cycle can be calculated
as a function of the useful work and the input heat to the
burner.
𝜂 =
𝑚 𝐶 𝑝 ∆𝑇
𝑇𝑢
− 𝑚 𝐶 𝑝 ∆𝑇
𝐶𝑜
𝑚 𝐶 𝑝 ∆𝑇
𝐶𝐶
= (3)
Thus, the higher efficiency can be achieved by reducing the
amount of burned fuel in the combustor. This can be
achieved by raising the compressor discharge temperature
prior the burner using the exhuased air from the turbine.
𝑄𝑎𝑐𝑡 = ε × 𝑄 𝑀𝑎𝑥
(4)
So, as the temperature difference between the turbine
exhuast and the compressor dicsharge increases, the
maximum amount of transferred heat ( 𝑄 𝑀𝑎𝑥 ) will go up
uielding to lower required fuel flow.
Another factor which affects the actual heat transfer rate in
the recuperator is the effectiveness. However, the higher
effectiveness requires larger heat transfer area which
obviously yields to larger heat exchanger size as will be
investigated further in this study.
4. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
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Volume: 04 Issue: 09 | September-2015, Available @ http://www.ijret.org 4
3.2 Determination of Gas Properties at Recuperator
Sides
The outlet pressure and temperature fromthe shell and tube
can be determined by calculation from:
𝑃2 = 𝑃1 × 1 −
∆𝑃 (%)
100
(5)
𝑇𝑐𝑜𝑙𝑑 ,𝑜𝑢𝑡 = 1 − 𝜀 × 𝑇𝑐𝑜𝑙𝑑 ,𝑖𝑛 + 𝜀. 𝑇 𝑜𝑡 ,𝑖𝑛 (6)
The dynamic viscosity can be calculated as a function of the
average temperature only using a correlation published by
Crane Company [3]. This equation is used for some
common gases and it was derived based on assumption that
the impact of pressure is minor (≤10% for the gases) and
can be neglected.
𝜇
𝐾𝑔
𝑚. 𝑠
=
1.5105 × 10−6
× 𝑇𝑎𝑣𝑔
1.5
𝑇𝑎𝑣𝑔 + 120
(7)
Where: 𝑇𝑎𝑣𝑔 is the average temperature in Kelvin (ºk)
The thermal conductivity (K) can be determined for hot and
cold streams using the correlation given by PasterAguilar
study [4]. This also has been developed assuming that the
thermal conductivity is a function of the average
temperature only.
𝐾
𝑊
𝑚. 𝐾
= 1.5207 × 10−11
× 𝑇𝑎𝑣𝑔
3
− 4.8574
× 10−8
× 𝑇𝑎𝑣𝑔
2
+ 1.0184
× 10−4
× 𝑇𝑎𝑣𝑔 − 3.9333
× 10−4
(8)
To calculate the specific heat, the correlation given by Ieradi
[5] is used. This equation has been derived experimentally
by plotting the variation of specific heat (𝐶 𝑝) against
temperatures which has been done by. However, this
formula determines the specific heat (𝐶 𝑝) in terms of the
average temperature only without a considering of the fuel
flow effect.
𝐶 𝑝
𝐽
𝐾𝑔. 𝐾
= 1.9327 × 10−10
× 𝑇𝑎𝑣𝑔
4
− 7.9999
× 10−7
× 𝑇𝑎𝑣𝑔
3
+ 1.1407
× 10−3
× 𝑇𝑎𝑣𝑔
2
− 4.4890
× 10−1
× 𝑇𝑎𝑣𝑔 + 1.0575 × 103
(9)
3.3 Heat Exchanger Design Theory
Four input parameters can be selected to modify the tube
geometry; these are:
Tube outside diameter (Dt)
Tube wall thickness (tt)
Tube roughness
Tube length (lt)
The inlet tube diameter (𝑑 𝑡 ) can be calculated based on the
specified tube outside diameter and its wall thickness.
Besides, the LMTD method is used to determine the
required tube area corresponding to the assumed overall heat
transfer coefficient (𝑈)by applying the following equation.
𝐴𝑡 =
𝑄 𝑎𝑐𝑡𝑢𝑎𝑙
𝑈 × 𝐿𝑀𝑇𝐷
=
𝑄 𝑎𝑐𝑡𝑢𝑎𝑙
𝑈 ×
𝑇1−𝑡2 −(𝑇2−𝑡1)
𝑙𝑛
𝑇1 −𝑡2
(𝑇2 −𝑡1)
(10)
For higher effectiveness, the direction of flow is assumed to
be counter-flow so the correction value (F) is substituted by
one. Then, the number of required tubes can be calculated
using the formula below.
𝑁𝑡 =
𝐴𝑡
𝜋 × 𝐷𝑡 × 𝑙 𝑡
(11)
The cold air is coming from the compressor at high pressure
and velocity. So, it is necessary to ensure that the high
velocity will not cause a high pressure drop within the tubes.
The velocity throughout the tubes can be determined from
the obtained number of tubes per pass and by knowing the
total inlet flow rate of the discharge compressor air.
Numerically, the Darcy friction factor can be calculated
directly using Swamee and Jain's equation [6] without
iteration.
𝑓 = 0.25 𝑙𝑜𝑔
ε/dt
3.7
+
5.74
𝑅𝑒𝑡
0.9
−2
(12)
The tubes are assumed to be straight so that the flow is
considered as fully developed. Thus, the frictional pressure
drop (∆𝑝𝑓 ) is derived from the equation of the fanning
friction factor. Besides, the combined header and tube
entrance losses (∆𝑝𝑒𝑛𝑡 ) can be estimated using the velocity
inside the tubes (𝑉𝑡 ). So, the total pressure drop of tube side
(∆𝑝𝑡 ) is calculated from:
∆𝑝 𝑡 = 4 × 𝑓
𝑙 𝑡
dt
×
𝜌 × 𝑉𝑡
2
2
+ 3
𝜌 × 𝑉𝑡
2
2
× 𝑛
(13)
5. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
_______________________________________________________________________________________
Volume: 04 Issue: 09 | September-2015, Available @ http://www.ijret.org 5
Figure 5: Developed Methodology for Heat Exchanger
Design
The flow of the cold compressor discharge air is turbulent
and the cross sectional area of the tubes is usually not large
enough to allow laminar flow. So, the inside heat transfer
coefficient for turbulent flow can be determined by equation
(14).
𝑖 = 𝑎
𝑘𝑡
dt
× 𝑅𝑒0.8
× 𝑃𝑟1/3
(14)
Different sources offer various values for the formula
coefficient (a) ranging from 0.019 to 0.027 so the average
value is taken in this study.
In order to obtain realistic results, the outside heat transfer
coefficient (𝑠 ) will be calculated using Bell-Delaware
method [7]. Despite its relative complexity, this technique
has been proven to provide more accurate and reliable
estimation and it is used frequently in the industry today.
Based on this method, the outside heat transfer coefficient
(𝑠 ) can be calculated using the following equation:
𝑠 = 𝑖 × 𝐽 𝑐 × 𝐽𝑙 × 𝐽 𝑏 × 𝐽 𝑠 × 𝐽 𝑟 (15)
The ideal heat transfer coefficient (𝑖 ) is determined by
applying correlation (16).
𝑖 = 𝑎1
1.33
𝑝 𝑡/Dt
𝑎 3
1+0.14 𝑅𝑒 𝑠
𝑎 4
× 𝑅𝑒 𝑠
𝑎2 × 𝐶 𝑝𝑠 ×
𝑚 𝑠
𝑆 𝑚
×
𝐾𝑠
𝐶 𝑝𝑠 𝜇 𝑠
2/3
(16)
The segmental baffle window correction factor ( 𝐽 𝑐) and
baffle leakage correction factor (𝐽𝑙) is obtained from
equations (17) and (18).
𝐽𝑐 = 0.55 +×
0.72
𝜋
𝜋 + 2
𝐷𝑠 − 2𝐿 𝑐
𝐷𝑜𝑡𝑙
𝑠𝑖𝑛 cos−1
𝐷𝑠 − 2𝐿 𝑐
𝐷𝑜𝑡𝑙
− 2cos−1
𝐷𝑠 − 2𝐿 𝑐
𝐷𝑜𝑡𝑙
(17)
𝐽𝑙 = 0.44 1 −
𝑆 𝑠𝑏
𝑆 𝑠𝑏 + 𝑆𝑡𝑏
+ 1
− 0.44 1 −
𝑆 𝑠𝑏
𝑆 𝑠𝑏 + 𝑆𝑡𝑏
exp −2.2
×
𝑆 𝑠𝑏 + 𝑆𝑡𝑏
𝑆 𝑚
(18)
The bypass correction factor (𝐽 𝑏) is determined based on the
ratio of sealing strips to tubes crossings ( 𝑟𝑠𝑠 ) as following:
If 𝑟𝑠𝑠 < 0.5
𝐽 𝑏 = 𝑒𝑥𝑝 −𝐶 𝑏 ×
𝑙 𝑠 × 𝐷𝑠 − 𝐷𝑜𝑡𝑙 + 0.5𝐷𝑡 × 𝑁 𝑝
𝑆 𝑚
× 1 − 2 × 𝑟𝑠𝑠
3
(19)
If 𝑟𝑠𝑠 ≥ 0.5
𝐽 𝑏 = 1 (20)
The correction factor of unequal baffle spacing ( Js) is
calculated using below formula assuming an equal spacing
for the inlet and outlet baffles (𝐿𝑖 = 𝐿 𝑜 )
𝐽 𝑠 =
𝑁𝑏 − 1 + 𝐿𝑖
∗ 1−𝑛
+ 𝐿 𝑜
∗ 1−𝑛
𝑁𝑏 − 1 + 𝐿𝑖
∗
+ 𝐿 𝑜
∗
(21)
Where:
𝑛: Formula exponent = 3
5
for 𝑅𝑒 𝑠 ≥100
1
3
for 𝑅𝑒 𝑠<100
The correction factor of adverse temperature gradient (Jr) is
based on the shell flow Reynolds number (𝑅𝑒 𝑠).
So, if 𝑅𝑒𝑠 < 20
6. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
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Volume: 04 Issue: 09 | September-2015, Available @ http://www.ijret.org 6
𝐽𝑟 = 𝐽 𝑟 𝑟
=
10
𝐷 𝑠−2𝐿 𝑐
𝑋 𝑙
+
0.8
𝑋 𝑙
𝐿 𝑐 −
𝐷 𝑠−(𝐷 𝑜𝑡𝑙 −𝐷 𝑡)
2
×(𝑁𝑏 + 1)
0.18
(22)
If 20 ≤ 𝑅𝑒𝑠 ≤ 100
𝐽 𝑟 = 𝐽 𝑟 𝑟 +
20−𝑅𝑒𝑠
80
× 𝐽 𝑟 𝑟 − 1
(23)
If 𝑅𝑒𝑠 > 100
𝐽 𝑟 = 1 (24)
The shell-side pressure drop (∆𝑃𝑠 ) is determined by
summing the pressure drops of three regions in the shell
which are the interior cross section (∆𝑃𝑐 ), shell window
(∆𝑃𝑤 ) and end zones (∆𝑃𝑒 ).
∆𝑃𝑠 = ∆𝑃𝑐 + ∆𝑃𝑤 + ∆𝑃𝑒 (25)
4. EXISTING GAS TURBINE MODELS
EVALUATION: CASE STUDY (1)
Five different models of gas turbines have been analyzed
and table 1 shows their calculated performance parameters
with less than 1% average deviation of each engine from the
OEM specifications. These engines will be called by: W6B,
W6FA, W9E, W7FA and W9FA respectively.
Figure 6 illustrates the difference between EGT and CDT of
these engines and how it varies with power setting at ISO
conditions (1atm, 15ºC). This is an important factor that
indicates the usefulness of the retrofit of a heat exchanger.
As this temperature difference increases, the amount of
transferred heat will increase with a consequent benefit on
thermal efficiency.
On the other hand, the negative value at low part load
operation would be detrimental to the overall efficiency of
the recuperative cycle. Based on this result, this kind of
cycles is not useful at less than 50% of the engine full load
capability.
When space for the heat exchanger installation is limited,
the engine with the lowest mass flow should be selected to
apply the recuperation retrofit. Coincidently, moderate
pressure ratio gas turbines also exhibit high specific power.
Table 1: Specifications of the Modelled Gas Turbines at
ISO Conditions and Design Point Operation
Model Parameter Value
W6B
ISO Rating Power (MW) 42.1
Pressure Ratio 12.2
Thermal Efficiency (%) 32.64
Exhaust Temperature (ºC ) 561
Flow Rate (kg/s ) 141.1
Firing Temperature (ºC ) 1140
W6FA
ISO Rating Power (MW) 70
Pressure Ratio 14.9
Thermal Efficiency (%) 34.86
Exhaust Temperature (ºC ) 600.53
Flow Rate (kg/s ) 196
Firing Temperature (ºC ) 1288
W9E
ISO Rating Power (MW) 126
Pressure Ratio 12.6
Thermal Efficiency (%) 33.68
Exhaust Temperature (ºC ) 548.44
Flow Rate (kg/s ) 418
Firing Temperature (ºC ) 1124
W7FA
ISO Rating Power (MW) 168
Pressure Ratio 14.8
Thermal Efficiency (%) 36.89
Exhaust Temperature (ºC ) 596.22
Flow Rate (kg/s ) 432
Firing Temperature (ºC ) 1288
W9FA
ISO Rating Power (MW) 227
Pressure Ratio 15
Exhaust Temperature (ºC ) 598.60
Mass Flow (kg/s) 602
Firing Temperature (ºC ) 1288
Figure 6: Predicted Temperature Difference of Simulated
Simple Cycle Gas Turbine Models at ISO Conditions
7. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
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Volume: 04 Issue: 09 | September-2015, Available @ http://www.ijret.org 7
Figure 7: Deviation of Specific Fuel Consumption from
ISO Fuel consumption
Heat exchangers are subjected to high thermal stresses
especially during start up. So these cycles are not
recommended for applications where the frequent starts are
required such as peak load electricity generation [8].So, two
hypothetical industrial gas turbines have been selected to
apply the recuperation retrofit: the W6B and W7FA from
Table 1.
Figure 7 illustrates the specific fuel consumption of the
simulated engines at various operating temperature. It is
interesting to observe that when the high ambient
temperatures of the operating environment are dominant, the
recuperative cycle is expected to be a good solution to
recover some of the wasted heat to reduce the high fuel
consumption at high ambient temperatures.
5. NEW METHOD VALIDATION: CASE STUDY
(2)
Two single shaft heavy duty gas turbine models have been
used to evaluate the derived method. These engines are
selected based on the conducted optimization in the previous
section. The obtained performance parameters of the simple
cycle are compared with the measured data as shown in
table 2. The conducted compression revealed a good
matching with the actual parameters with the maximum
uncertainty of about ±2.3 in the exhaust temperature of the
frame 6B engine. This percentage is acceptable since it is
still below the maximumallowed deviation.
The performance results obtained from the simple cycle
simulation are used to determine the inlet conditions of both
recuperator streams as indicated in table 3. The terms
W6BRC and W7FARC donate the recuperative cycle of the
frames 6B and 7FA engines respectively. The stated
effectiveness and pressure drop values are for the proposed
design by the manufacture which will be evaluated and
compared with the other design options.
Table 2: Comparison between Predicted and Measured Gas
Turbine Cycle Parameters
Model
Parameter
Measure
d
Predicte
d
Relative-
Differences
%
Frame6B
ISO Rating Pow er
(MW)
42.1 42.1 0
Pressure Ratio 12.2 12.2 0
Thermal Efficiency
(%)
32.1 32.64 1.68
Exhaust
Temperature (ºC )
548 561 2.3
Flow Rate (kg/s ) 141.1 141.1 0
Firing
Temperature (ºC )
1140 1140 0
Frame7FA
ISO Rating Pow er
(MW)
168 168
0
Pressure Ratio 14.8 14.8
0
Thermal Efficiency
(%)
36.2 36.89
1.9
Exhaust
Temperature (C )
594 596.22
0.4
Flow Rate (Kg/s ) 432 432
0
Firing
Temperature (C )
1288 1288
0
Table 3: Inlet and Outlet Conditions of Recuperator Streams
HX Side
W6BRC W7FARC
Cold Hot Cold Hot
Inlet temperature
(°k )
620 834 646 873
Inlet Pressure
(kpa )
1223 103 1492 103
Mass Flow (kg/s) 130 143 386 440
2.33
Proposed
Pressure Drop by
OEM (kpa)
18 2.33 22.38
ProposedEffectiv
eness by OEM
(%)
83 83 83 83
This study is focusing on the industrial heat exchangers
which can be classified according to several criteria
including: construction, surface compactness, flow
arrangements, number of passes, fluids phase and heat
transfer mechanism. In such applications, the high gas
turbine efficiency is the primary objective. Additionally, the
pressure ratios and mass flows of the gas turbines are
relatively high.
8. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
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Volume: 04 Issue: 09 | September-2015, Available @ http://www.ijret.org 8
So, the recuperative type of heat exchangers will be used
here to carry out the required heat transfer process. The shell
and tube heat exchanger with a counter-flow arrangement
will be considered here since it is the most effective among
the other types. The design methodology is set based on
some stated assumptions which are.
Steady state only will be considered in this study.
Recuperator is insulated from its surroundings so heat
losses to or from the surroundings are negligible.
No phase change - all fluids remain in gas phase.
Constant fluids properties and heat transfer coefficients
Inlet velocity and temperature of each stream are
uniformover the flow cross section.
Mass flow of each stream is assumed to be uniformly
distributed throughout the recuperator.
The flow velocity has a significant impact on the
performance characteristics of the heat exchanger and
overall cycle. Hence it has been used the key design
criterion to select the recuperator design features. The
dependence on the inlet flow velocity makes this
methodology quite unique and simple to follow by the user.
For simplicity, the design process will be carried assuming
an equal flow velocity of both streams. Figure 8 illustrates
the flow velocity influences on the heat transfer coefficient
and pressure drop of tube-side. It is clear that the tube heat
transfer coefficient is varying with approximately 0.8 power
of cold flow velocity, whereas the tube side pressure drop
varies with the flow velocity square.
Figure 8: Flow Velocity Effect on Heat Transfer Coefficient
and Pressure Drop of Tube-Side
The shell heat transfer coefficient increases with flow
velocity but with less sensitivity compared with that of tube
side (figure 9). Moreover, the increase in the inside and
outside heat transfer coefficients will enhance heat transfer
which will lead to a lower heat transfer area.
To allow for the flow velocity rise, the flow rate per tube
should be increased which can be achieved by reducing the
number of tubes and heat transfer area. Consequently, the
heat exchanger size is reduced with higher flow velocity.
However high flow velocity results in increased the pressure
drop; this is increasing faster than the heat transfer
coefficient. Thus, the rise in the overall pressure drops of
both sides is greater than the rise in heat transfer coefficient.
Additionally, with low flow velocity, the increase in heat
exchanger size and its heat transfer area allows for higher
amount of heat transfer from the hot stream to cold stream.
Hence the actual heat transfer will increase and the
recuperator effectiveness will be higher as shown in figures
10 and 11.
When the gas flows through the heat exchanger, the gas
velocity induces a fluid friction which leads to reduce the
gas pressure. As, the value of pressure drop increases, more
power will be required to move the fluid which will reduce
gas turbine power the thermal efficiency. At the same flow
velocity of both recuperator streams, the absolute pressure
drop in cold side is significantly greater than that of hot side
due to the higher inlet pressure of the cold stream. However,
the fractional pressure drop of both stream were relatively
closer as observed in figure 10 wherethe dotted line
indicates the estimated physical size of the proposed design
by the manufacture.
Although, the high flow velocity helps to reduce the
recuperator size, the resulting pressure drops will cause a
greater reduction in power output and thermal efficiency.
9. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
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Figure 10: Influence of Recuperator Size on the
Effectiveness and Pressure Drop of W6BRC
Figure 11: Influence of Recuperator Size on the
Effectiveness and Pressure Drop of W7FARC
Considering the recuperator effectiveness, a large
recuperator offers increased heat transfer area; hence the
actual heat transfer rate and the recuperator effectiveness
will increase. Moreover, the recuperator size is increasing as
the flow velocity reduces. For example: the recuperator size
has increased by 39% over the actual size when the flow
velocity of both streams reaches 15m/s comparing with the
size increase of 107.7% at 10m/s flow velocity.
Figure 11 indicates that the actual size of W7FARC heat
exchanger at the design point is located in the large size
region. This is needed to avoid the consequential high
pressure drop at the small size region of the curve. When the
flow velocity is reduced to 5m/s, the recuperator size
increases by 28.4% with pressure drops reached to 1.76%
and 0.358% of the hot and cold sides respectively and with
an effectiveness of 91.6%. On the other hand, in the case of
higher flow velocity and at 7.5m/s, the size has been
reduced by only 14% with an effectiveness of 87.25%. So,
technically, this point is accepted as design point to
compromise between the low pressure drop value and
smaller physical size.
These two figures can be used as a guide to select the
recuperator parameters based on the application
requirements and in order to meet the required improvement
in the overall cycle efficiency. Each value represents
different design point of the recuperator cycle and the
effects on the power output and overall efficiency of both
engines are shown in the figures 12 and 13.The power
output of both engines is increasing as the recuperator size
increases as a result of pressure drop reduction. Moreover
and as the flow velocity decreases, the high heat
effectiveness values at larger recuperator size result in a
lower fuel flow requirement. Furthermore, at very high flow
velocity and small recuperator size, there is a change in the
fuel flow trend in which it starts to decrease slightly. This is
basically due to the greater associated pressure drop in both
recuperator sides which in turn yields to higher reduction in
the rated power as illustrated in the same figures.
The significant drop in the rated power as the recuperator
flow velocity approaches 25m/s is affected by the low inlet
turbine pressure due to the high induced pressure drop
through the heat exchanger tubes. This leads to lower
turbine expansion rate and in consequence a higher
discharge turbine temperature. The inlet shell temperature is
increasing as the recuperator flow velocity and pressure
drop raise.
Figure 1: Influence of Recuperator Size on the Power
Output and Efficiency of W6BRC
10. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
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Figure 2: Influence of Recuperator Size on the Power
Output and Efficiency of W7FARC
However, the low heat transfer effectiveness between the
recuperator streams at high velocity region normally
overcomes the high inlet temperatures of the shell flow
yielding to lower tubes discharge temperatures and higher
required amount of fuel in the combustor.
On the other hand and as the recuperator flow velocity
increases further, the effect of high inlet hot-stream
temperature starts becoming the dominant factor against low
effectiveness values.Hence, the air enters the combustor at
relatively greater temperatures which accordingly reduces
the required fuel flow. Regarding to the rated power, the
lower turbine expansion rate as the inlet turbine pressure
decreases and the recuperator flow velocity increases
causing a continuous drop in the power output.
Figure 14: Influence of Flow Velocity of Recuperator
Streams on the Overall Cycle Fuel Flow at Full Load
Operation
Besides, the lower fuel flow at very high flow velocity leads
to relatively a lower inlet turbine flow which can considered
as a contribution factor causing a further drop in the power
output. An interesting observation was that the thermal
efficiency is improving continuously with the recuperator
size increase despite the reduction in the fuel flow at high
flow region. In fact, this can be explained by considering the
slope of the power change curve comparing with the fuel
flow variation trend which shows that the reduction in
power output is accelerating faster than the fuel flow drop.
6. EFFECT OF PART-LOAD OPERATION
By applying the recuperation, the fuel flow of W6B has
been reduced by 21.2% with 7.47% increase in its thermal
efficiency. Besides, the fuel flow of the engine W7FARC is
lower than that of the simple cycle by 19.42% with 7%
improvement in the thermal efficiency.
However, the power output of the engines W6B and W7FA
have been decreased by about 3.2% and 4.1% respectively
which in turn leads to reduce the specific work slightly.
Besides, although there is a drop in the rated power, the
thermal efficiency increased significantly due to the higher
reduction in fuel flow comparing with the power output
drop.
Based on the fuel flow, Figure 15demonstrates that the
reduction in the fuel flow due to the use of recuperation
began at 42%FL. However, the deviation between the fuel
flow of simple and recuperative cycles is increasing
significantly as the turbine load goes up.
Figure 15: Fuel Flow at Part-Load Conditions of
Recuperative and Simple Cycles using TET Control at ISO
Conditions
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Figure 16: Thermal Efficiency at Part-Load Conditions of
Recuperative and Simple Cycles using TET Control at ISO
Conditions
Figure 16 illustrates the changes in the thermal efficiency of
the recuperative cycle at ISO conditions during part-load
operation. In the case of W6B gas turbine, the recuperative
cycle is not recommended at operating load lower than
42%FL. Operating the engine at part load lower than this
value will cause the recuperative cycle to be less efficient
than the simple cycle due to the reverse heat transfer from
the compressor discharge air to the turbine exhaust gas.
The difference in temperature between the two streams can
be identified from figure 6 in which the difference becomes
negative at lower than 42%FL operation. However,
W7FARC has a higher thermal efficiency than W7FA when
the turbine load exceeds 45% of its full load capability in
which the temperature of the exhaust gas will be greater
than that of compressor discharge air. As the compression
pressure ratio increases with the load rise, the use of
recuperation will be more efficient and useful as a result of
the increase in exhausted gas temperature so that more heat
can be absorbed to heat the compressor discharge air.
In the case W6BRC engine, the improvement in the thermal
efficiency due to the use of recuperation is reaching to 5%
and 7.47% at 85%FL and 100%FL, respectively.
Additionally, the difference in the thermal efficiency
between the recuperative and simple cycles of the engine
W7FA increased from 6% at 85%FL to 7% at full load
operation.
7. CONCLUSION
This paper introduces a new systematic analytical method
to:
Select an appropriate gas turbine among operating
units in the field for a recuperator retrofit.
Design a suitable recuperator
Evaluate the performance range of usefulness.
It was found that there isa trade-off between some of the
recuperator design features. A high effectiveness heat
exchanger is larger and affects the installation spacerequired
and the recuperator price. So, it is essential to find a
compromise between these features based on the specified
application and in order to satisfy the operation
requirements. The developed approach has been tested
using two gas turbines engines and the estimated cycle
parameters are compared with the actual values. One of the
unique features of the derived method is the fact that it
depends only on the flow velocity to derive the rest of
performance parameters. Besides, it can be used to evaluate
the existing operating gas turbines units for higher
performance achievement. However, it is important to
consider the economic viability of using the recuperative
cycle which will be covered in the second part of this
study.This is the topic of part II of this work.
ACKNOWLEDGMENTS
The first author would like to thank Petroleum Development
Oman Company and Cranfield University for supporting
this study.
NOMENCLATURE
𝑄 Amount of Heat Transfer
𝑉 Average Volumetric Flow Rate
𝐽 𝑟 Correction Factor of Adverse Temperature
Gradient in Laminar Flow
𝐽𝑙 Correction Factor of Baffle Leakage Effects
𝐽 𝑏 Correction Factor of Bundle Bypass Effects
𝐽 𝑠 Correction Factor of Unequal Baffle Spacing at
Inlet and/or Outlet
𝑣 Flow Velocity
𝐶, 𝑎1 , 𝑎2, 𝑎3, 𝑎4Empirical Coefficients
𝐹𝑐 Fraction of Total Tubes in Cross-flow
𝑑 𝑡 Inlet Tube Diameter
𝐹 Log-mean Temperature Difference Correction
Factor
𝑈 𝑚 Overall Heat Transfer Coefficient
∆𝑃𝑒 Pressure Drop of End Zones
∆𝑃𝑐 Pressure Drop of Interior Shell Cross Section
∆𝑃𝑤 Pressure Drop of Shell Window
𝑤 Recuperator Weight
𝐽 𝑐 Segmental Baffle Window Correction Factor
𝑜 Shell Heat Transfer Coefficient
𝐶 𝑃 Specific Heat
𝑘 Thermal Conductivity
12. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
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𝑖 Tube Heat Transfer Coefficient
𝑙 𝑡 Tube Length
𝐷𝑡 Tube Outside Diameter
𝜇 Viscosity
𝜀 Effectiveness
ABBREVIATIONS
CDT Compressor Discharge Temperature
EGT Exhaust Gas Temperature
FL Full Load
GT Gas Turbine
HX Heat Exchanger
LMTD Log Mean Temperature Difference
NTU Number of Transfer Units
NPV Net Present Value
OEM Original Equipment Manufacture
PS Physical Size
P Power Output
PR Pressure Ratio
RC Recuperative Cycle
SC Simple Cycle
TET Turbine Entry Temperature
SUBSCRIPTS
c Cold Stream
h Hot Stream
1 Inlet of Recuperator Stream
2 Outlet of Recuperator Stream
s Shell Side
t Tube Side
Co Compressor
Tu Turbine
CC Combustion Chamber
act Actual
Max Maximum
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