Shell and Tube Heat Exchanger

In this paper, the new approach of constructal theory has been employed to design shell and tube heat exchangers. Constructal theory is a new method for optimal design in engineering applications. The purpose of this paper is optimization of shell and tube heat exchangers by reduction of total cost of the exchanger using the constructal theory. The total cost of the heat exchanger is the sum of operational costs and capital costs. The overall heat transfer coefficient of the shell and tube heat exchanger is increased by the use of constructal theory. Therefore, the capital cost required for making the heat transfer surface is reduced. Moreover, the operational energy costs involving pumping in order to overcome frictional pressure loss are minimized in this method. Genetic algorithm is used to optimize the objective function which is a mathematical model for the cost of the shell and tube heat exchanger and is based on constructal theory. The results of this research represent more than 50% reduction in costs of the heat exchanger.► In this paper, constructal theory has been employed to optimization of shell and tube heat exchangers. ► Heat exchangers optimized by reduction of total cost using Constructal theory. ► The overall heat transfer coefficient of the heat exchanger is increased. ► Genetic algorithm is used to optimize the objective function. ► The results of this research represent more than 50% reduction in cost.

To figure out the best baffle cut to obtain the maximum overall heat transfer coefficient for the better performance of shell and tube heat exchanger. Methods: To identify the best relation between the baffle cut and overall heat transfer coefficient, six different baffle cut varies from 15% to 40% were taken at the same mass of fluid. To analyze thermal design and overall heat transfer coefficient HTRI was used. To find out the relation between the baffle cut to overall heat transfer coefficient, we generated 2d profile corresponding to length and 3d profile for local heat transfer coefficient. We compared all six design variations to analyze the variation in overall heat transfer coefficient. After comparison of all six variations we figured out optimum relationship between Baffle cut and Overall Heat Transfer Coefficient. Result shows that at a particular cut the rate of heat transfer is the maximum. We found that 25% baffle cut is the optimum cut for single segmental baffle, this provides best combination of shell side velocity and B stream and generate enough turbulence for better heat transfer coefficient. It is also demonstrating good distribution of heat transfer in all localities of heat exchanger. If we decrease the baffle cut, it may increase turbulence but leads to decrease the shell side velocity and B stream, this results the less heat transfer coefficient. Similarly, by increasing the baffle cut there is increase in shell side velocity and B stream, but due to less turbulence less heat transferred. So there is less heat transfer coefficient. Thus for beat the performance of heat exchanger and optimum heat transfer coefficient, there should be best combination of all effective variables.

In heat exchanger tubes are mainly subjected to the thermal treatment. In order to enhance the efficiency of heat exchanger. Many strategies has been proposed & analyzed for the better results of heat transfer performance. Similarly in this content of paper a new strategy has been opted i.e. using square and triangular cross sectional geometries of tube of shell and tube heat exchanger and comparing its analytical results with that of circular cross sectional geometry of tube of shell and tube heat exchanger.

The aim of the study is design tube and box heat exchanger with various pattern of
tubes and examine the flow and temperature field at inlet and outlet point of tube and
container using ANSYS programming tool. Three types of heat exchangers are
planned in this examination with various structures of cylinders contains of 175 mm
breadth and 1000 mm length shell measurement 175 mm. To expand the rate of heat
exchange of heat exchanger advancement is done which tries to distinguish the best
parameter combination of heat exchangers. The prefix parameter (tube width) is
utilized as an info variable and the yield parameter is the most extreme temperature
distinction of container and tube heat exchanger. Three types models are design on
the basis tubes varieties of heat exchanger and CFX examination is completed in
ANSYS 14.0.

In this study, numerical simulation was used to investigate the effect of adding different nano-particles into the fluid on the performance of a bafed shell-and-tube heat exchanger. A three-dimensional modeling approach was followed to analyze the effect of different nano-fluids, at various volume fractions, as applied in a bafed shell-and-tube heat exchanger. Once fnished with validating the grid independency and results, we proceeded to obtain heat transfer rate, pressure drop, outlet shell temperature and exchanger effectiveness for different volume fractions and particle size of different nanofluids. The studied nano particles in the present work included Al2O3, CuO, Fe2O3, Cu, Fe, SiO2, and Au, with water and ethylene glycol employed as base fluids. With constant mass flow rate for all cases, the results indicated that, the addition of nano-particles had reduced the heat transfer coefcient, pressure drop and the rate of heat transfer through the shell, even though it had increased outlet shell temperature. In other words, considering a constant heat transfer rate, the presence of nanofluids in a bafed shell-and-tube heat exchanger is likely to be associated with increased outlet shell temperature. Another consequence presents that using ethylene glycol as base fluid leads to higher effectiveness compared with water as a base fluid in exchanger.

As their name implies, Heat exchangers are used where is needed to heat transfer between a fluid and a solid object or two or more fluids in order to control the system temperature. In such devices, Heat transfer could be feasible by two ways: direct and indirect contact of fluids. Heat exchangers are very common in many industrial applications such as chemical and petrochemical plants, power stations, refrigeration and air conditioning systems, petroleum refineries, sewage treatment, etc. a good commonplace example of using heat exchangers in our daily life is the car radiator. Shell and tube heat exchangers are the most usual types of heat exchangers in industries which are robust and heavy duty because of their shape (they are typically suitable for higher pressure use). There are various types of baffles for shell and tube heat exchangers such as segmental (single and double segmented baffles), helical, disc and doughnut, etc. which are used to direct the fluid across the tube b...

Due to the high enthalpy of fusion in water, ice storage systems are known as one of the best cold thermal energy storage systems. The phase change material used in these systems is water, thus it is inexpensive, accessible, and completely eco-friendly. However, despite the numerous advantages of these systems, the phase change process in them is time-consuming and this leads to difficulties in their practical application. To solve this problem, the addition of nanomaterials can be helpful. This study aims to investigate the compound heat transfer enhancement of a cylindrical-shaped unit equipped with double helically coiled coolant tubes using connecting plates and nano additives as heat transfer augmentation methods. Complex three-dimensional numerical simulations are carried out here to assess the best heat exchanger material as well as the impact of various nanoparticle types, including alumina, copper oxide, and titania, and their concentrations in the PCM side of the ice storage unit. The influence of these parameters is discussed on the charging rate and the temperature evolution factor in these systems. The results suggest that using nano additives, as well as the connecting plates, together is a promising way to enhance the solidification rate by up to 29.9%.

Automotive engines eliminate a considerable amount of heat energy to the environment through the exhaust gas. Significant reduction of engine fuel consumption could be attained by recovering of exhaust heat by using thermoelectric generators. One of the most important issues is to develop an efficient heat exchanger which provides optimal recovery of heat from exhaust gases. The work presents a design and performance measurements of a prototype thermoelectric generator mounted on self-ignition (Diesel) engine. Using the prototype generator as a tool, benchmark studies were performed for improvements in the heat exchanger including determination of temperature distribution and heat flux density.

This article reports an experimental study on the forced convective heat transfer and flow characteristics of a nanofluid consisting of water and different volume concentrations of Al 2 O 3 nanofluid (0.3–2)% flowing in a horizontal shell and tube heat exchanger counter flow under turbulent flow conditions are investigated. The Al 2 O 3 nanoparticles of about 30 nm diameter are used in the present study. The results show that the convective heat transfer coefficient of nanofluid is slightly higher than that of the base liquid at same mass flow rate and at same inlet temperature. The heat transfer coefficient of the nanofluid increases with an increase in the mass flow rate, also the heat transfer coefficient increases with the increase of the volume concentration of the Al 2 O 3 nanofluid, however increasing the volume concentration cause increase in the viscosity of the nanofluid leading to increase in friction factor.

Shell and Tube heat exchangers are having special importance in boilers, oil coolers, condensers, pre-heaters. They are also widely used in process applications as well as the refrigeration and air conditioning industry. The robustness and medium weighted shape of Shell and Tube heat exchangers make them well suited for high pressure operations. The aim of this study is to experiment, validate and to provide design suggestion to optimize the shell and tube heat exchanger (STHE). The heat exchanger is made of acrylic material with 2 baffles and 7 tubes made of stainless steel. Hot fluid flows inside the tube and cold fluid flows over the tube in the shell. 4 K-type thermocouples were used to read the hot and cold fluids inlet and outlet temperatures. Experiments were carried out for various combinations of hot and cold water flow rates with different hot water inlet temperatures. The flow conditions are limited to the lab size model of the experimental setup. A commercial CFD code wa...

A B S T R A C T Shell and tube heat exchanger is one of the most prevalent heat exchangers with a wide variety of industrial applications, i.e., power plants, chemical processes, marine industries, HVAC systems, cooling of hydraulic fluid and engine oil in heavy duty diesel engines and the like specifically where a need to heat or cool a large fluid volume exist and also higher-pressure use. In the present study, the effect of using Al 2 O 3-water nanofluid on thermal performance of a commercial shell and tube heat exchanger with segmental baffles is assessed experimentally. For this purpose, Al 2 O 3-gamma nanoparticles with 15 nm mean diameter (99.5% purity) and Sodium Dodecyl Benzene Sulphonate (SDBS) as surfactant are used to make aqueous Al 2 O 3 nanofluid at three various volume fractions of nanoparticles (φ = 0.03, 0.14 and 0.3%). Indeed, in this paper the effect of some parameters of hot working fluid such as Reynolds number and volume concentration of nanoparticles on heat ...

En este trabajo se presenta un procedimiento general para la simulación del comportamiento del flujo en los intercambiadores de tubos y aletas con una gran flexibilidad en el manejo de la información. Este procedimiento está basado en el uso de Programación Orientada a Objetos y específicamente al uso de C++, esto debido a todas las ventajas de este tipo de programación. La entrada de datos se lleva a cabo por medio de archivos, de forma que programas de terceros puedan generar la configuración del intercambiador y permitir calcular el intercambiador en forma paramétrica. Los resultados para el análisis se presentan en tres formatos diferentes: valores separados por comas (CSV), texto plano estructurado y autodocumentado (XML) y un formato para la visualización gráfica de resultados (VTK).

ABSTRACT This paper presents the performance of a wire-on-tube heat exchanger of which the wire is an oscillating heat pipe. The experiments for this heat exchanger were performed in a wind tunnel by exchanging heat between hot water flowing inside the heat exchanger tubes and air stream flowing across the external surface. R123, methanol and acetone were selected as working fluids of the oscillating heat pipe. The inlet water temperature was varied from 45 to 85 °C while the inlet air temperature was kept constant at 25 °C. The results show that the oscillating heat pipe technique for all working fluids could increase around 10% of the heat transfer rate obtained from that without the refrigerant flow in the capillary tube when the inlet water temperature is at 60 °C. Moreover, the heat transfer models for evaluating the heat exchanger effectiveness and the air-side heat transfer coefficient, are also developed in this work. These results of the models agreed very well with the experimental data.

Abstract: An attempt made to decrease the pressure drop and to increase the heat transfer and the ratio of heat transfer and pressure drop in shell and tube type heat exchanger by tilting the baffle angle up to which we get the minimum pressure drop. This study however, considers shell and tube type heat exchanger with the aid of computer programming. It involves developing a simple user-friendly computer programme for the heat transfer calculations and ensures that the computational time is kept minimal. Analysis has been done in shell and tube type heat exchanger at shell side. It analyzes the conventional segmental baffle heat exchanger using the Kern’s method with fixed shell side flow rates and varied volume flow rate. Since Kern ’ method used in design of heat exchangers with a baffle cut of 25 % (fixed). The thermal analysis of helical baffle heat exchanger using this method give us clear idea that the ratio of heat transfer coefficient per unit pressure drop is maximum in he...

PC-based controller is an approach to control systems with Real-Time parameters by controlling selected manipulating variable to accomplish the objectives. Shell and tube heat exchanger have been identified as process models that are inherently nonlinear and hard to control due to unavailability of the exact models' descriptions. PC and analogue input output card will be used as the controller that controls the heat exchanger hot stream to the desired temperature. The control methodology by using four speed pump as manipulating variable to control the temperature of the hot stream to cool to the desired temperature. In this work, the dynamics of cross flow shell and tube heat exchanger is modeled from step changes in cold water flow rate (manipulated variable). The model is identified to be First Order plus Dead Time (FOPDT). The objective of this work is to design and implement a controller to regulate the outlet temperature of hot water that is taken as controlled variable. Th...

Three variants of shell and tube heat exchangers with zero, six and eight helical baffles are investigated in the present study for the heat transfer performance with hot molten salt flowing in the tube at inlet temperatures 838K and 563K and cold thermal oil flowing in the shell. Three types of thermal oils namely Exceltherm SST, LV1 and MK1 were analysed for relative performance. It was observed that the temperature increases rapidly with increase in the number of helical baffles and higher temperatures are realised for all three oils for Solar Salt at 838K compared to Solar Salt at 563K. The possible reason could be due to restricted passages created between the baffles (with higher number of baffles) causing the cold fluid flowing in the shell having better contact with the hot fluid flowing in the tubes. The restricted passages result in higher velocities in between baffles and causes better heat transfer. Solar Salt and oil Exceltherm SST combination has the highest Nusselt Nu...

Fouling is a known dairy industry issue during thermal treatments using a plate heat exchanger (PHE) it directly affects not only energy costs and maintenance but also production, energy and water losses during cleaning operations. Therefore, a considerable attention has been paid to the modelling of the fouling phenomena in order to improve the PHE performances. In this paper, a mathematical model describing the steady state was established for the flow at the macroscopic scale; the model account for constant and turbulent flows between two flat parallel plates at imposed temperature in the presence of a porous medium. The closure k-ε model has been chosen and the conservation of equations has been developed. The numerical procedure adopted was based on the finite volume method on the Fluent CFD software. The accuracy of the Fluent software was validated by comparing our results with those previously published in the literature. The numerical results showed a good reliability of th...

The effect of baffle orientation on the heat transfer and pressure drop of shell and tube heat exchangers in the domain of turbulent flow is investigated numerically using the commercial CFD code FLUENT. The segmentally baffled shell and tube heat exchangers considered follow the ...

In this study, numerical simulation was used to investigate the effect of adding different nanoparticles into the fluid on the performance of a baffled shell-and-tube heat exchanger. A three-dimensional modeling approach was followed to analyze the effect of different nanofluids, at various volume fractions, as applied in a baffled shell-and-tube heat exchanger. Once finished with validating the grid independency and results, we proceeded to obtain heat transfer rate, pressure drop, outlet shell temperature and exchanger effectiveness for different volume fractions and particle size of different nano-fluids. The studied nanoparticles in the present work included Al2O3, CuO, Fe2O3, Cu, Fe, SiO2, and Au, with water and ethylene glycol employed as base fluids. With constant mass flow rate for all cases, the results indicated that, the addition of nano-particles had reduced the heat transfer coefficient, pressure drop and the rate of heat transfer through the shell, even though it had i...