A design process for cryogenic expanders that supplies 0.5 TPD of liquefied hydrogen in hydrogen ... more A design process for cryogenic expanders that supplies 0.5 TPD of liquefied hydrogen in hydrogen liquefaction plants is introduced. To improve the efficiency of the expander, the optimum design was conducted by adjusting two rotor shape parameters. The designed expander for hydrogen liquefaction has a target rotation speed of 75,000 rpm, and helium is applied as the working fluid. Since the operating temperature of the expander is as low as 49 K, a design that reflects the real gas properties must be considered. For a high-efficiency hydrogen liquefaction plant, increasing the expander efficiency is one of the most critical issues. In this study, the efficiency of the cryogenic expander was optimized using the response surface method (RSM). The hub and shroud meridional contours and blade β angle distributions were chosen as the design parameters. As a result, through the optimized design, it was possible to improve the expander efficiency by up to 1.98% compared to the original exp...
A fully coupled aero-elastic simulation technology is developed with enough sophistication to hav... more A fully coupled aero-elastic simulation technology is developed with enough sophistication to have the features required to perform loads analyses for a variety of wind turbine configurations. Blade and tower are modeled multiple rigid bodies which are connected beam elements to represent a flexibility for their bending and torsional behaviors. AeroDyn which is developed by NREL are chosen for aerodynamic analysis. This is a popular and open code and needs hub-height wind data, full field turbulent wind data and airfoil data to calculate an aerodynamic force. DAFUL, which is a commercial multi-body and structure dynamics analysis tool, is used for multi-body dynamics analysis considering a flexibility of the blade and tower. The interface to perform coupled analysis between these two softwares is developed with a user-subroutine of vector force in DAFUL. Analysis results of a sample model to verify This proposed simulation technology is applied to the analysis of a sample model for ...
Journal of the Korean Society for Precision Engineering, 2011
The light-weight design of UTM (Urban Transit Maglev)-02 car-body frames are performed, based on ... more The light-weight design of UTM (Urban Transit Maglev)-02 car-body frames are performed, based on initial configuration. The thicknesses of fourteen sub-structures are defined as design variables and the loading condition is considered according to weight of sub-structures, electronic and pneumatic modules and passengers. For efficient and robust process of design optimization, objective function and constraints are approximated by response surface approximation. Structural analysis is performed at some sampling points to construct the approximated objective function and constraints composed of design variables. Design space is changed to find many optimal candidates and best optimal design can be found eventually. The Matlab Optimization Toolbox is used to find optimal value and sensitivity analysis about each design variable is also performed.
Journal of Engineering for Gas Turbines and Power, 2017
Gas foil bearings (GFBs) have many noticeable advantages over the conventional rigid gas bearings... more Gas foil bearings (GFBs) have many noticeable advantages over the conventional rigid gas bearings, such as frictional damping of the compliance structure and tolerance to the rotor misalignment, so they have been successfully adopted as the key element that makes possible oil-free turbomachinery. As the adoption of the GFB increases, one of the critical elements for its successful implementation is thermal management. Even though heat generation inside the GFB is small due to the low viscosity of the lubricant, many researchers have reported that the system might fail without an appropriate cooling mechanism. The objective of the current research is to demonstrate the reliability of GFBs installed in the hot section of a micro-gas turbine (MGT). For the cooling of the GFBs, we designed a secondary flow passage and thermohydrodynamic (THD) analysis has been done for temperature prediction. In the analysis, the 3D THD model for the radial GFB extended to include the surrounding struct...
Transactions of the Korean Institute of Electrical Engineers, 2008
【This paper presents the status of advanced technologies and domestic researches for development ... more 【This paper presents the status of advanced technologies and domestic researches for development of Korean next generation maglev. Generally, two specific configurations such as the EMS (Electromagnetic Suspension) with LSM (Linear Synchronous Motor) and EDS (Electrodynamic Suspension) with LSM can be employed as a propulsion and levitation device of high-speed maglev. Worldwide high-speed maglev developments refer to projects such as the German Transrapid with EMS, the Japanese MLX with EDS, and the U.S. Inductrack with PM (Permanent Magnet) EDS maglev system. In this paper, the propulsion and levitation systems of these world wide high-speed maglev have been reviewed and analysed.】
A web based automation of fatigue durability analysis for a welded bogie frame of railway vehicle... more A web based automation of fatigue durability analysis for a welded bogie frame of railway vehicle is realized with several kinds of system integration techniques. The macro program of I-DEAS, the APDL of ANSYS, and an in-house fatigue code are utilized for the parametric geometry modeling and automatic generation of finite element models, the static stress analysis, the fatigue durability analysis, respectively. A multi-agent based engineering framework is implemented on the JADE to integrate the overall process. All engineering programs are integrated by a XML based wrapper. A database to contain engineering data and web based user interfaces are also developed. A parametric study is carried out to take into account the effect of geometrical change of transom support brackets on its fatigue durability. Developed automation techniques reduce remarkably the time and costs required in the fatigue durability analysis.
A design process for cryogenic expanders that supplies 0.5 TPD of liquefied hydrogen in hydrogen ... more A design process for cryogenic expanders that supplies 0.5 TPD of liquefied hydrogen in hydrogen liquefaction plants is introduced. To improve the efficiency of the expander, the optimum design was conducted by adjusting two rotor shape parameters. The designed expander for hydrogen liquefaction has a target rotation speed of 75,000 rpm, and helium is applied as the working fluid. Since the operating temperature of the expander is as low as 49 K, a design that reflects the real gas properties must be considered. For a high-efficiency hydrogen liquefaction plant, increasing the expander efficiency is one of the most critical issues. In this study, the efficiency of the cryogenic expander was optimized using the response surface method (RSM). The hub and shroud meridional contours and blade β angle distributions were chosen as the design parameters. As a result, through the optimized design, it was possible to improve the expander efficiency by up to 1.98% compared to the original exp...
A fully coupled aero-elastic simulation technology is developed with enough sophistication to hav... more A fully coupled aero-elastic simulation technology is developed with enough sophistication to have the features required to perform loads analyses for a variety of wind turbine configurations. Blade and tower are modeled multiple rigid bodies which are connected beam elements to represent a flexibility for their bending and torsional behaviors. AeroDyn which is developed by NREL are chosen for aerodynamic analysis. This is a popular and open code and needs hub-height wind data, full field turbulent wind data and airfoil data to calculate an aerodynamic force. DAFUL, which is a commercial multi-body and structure dynamics analysis tool, is used for multi-body dynamics analysis considering a flexibility of the blade and tower. The interface to perform coupled analysis between these two softwares is developed with a user-subroutine of vector force in DAFUL. Analysis results of a sample model to verify This proposed simulation technology is applied to the analysis of a sample model for ...
Journal of the Korean Society for Precision Engineering, 2011
The light-weight design of UTM (Urban Transit Maglev)-02 car-body frames are performed, based on ... more The light-weight design of UTM (Urban Transit Maglev)-02 car-body frames are performed, based on initial configuration. The thicknesses of fourteen sub-structures are defined as design variables and the loading condition is considered according to weight of sub-structures, electronic and pneumatic modules and passengers. For efficient and robust process of design optimization, objective function and constraints are approximated by response surface approximation. Structural analysis is performed at some sampling points to construct the approximated objective function and constraints composed of design variables. Design space is changed to find many optimal candidates and best optimal design can be found eventually. The Matlab Optimization Toolbox is used to find optimal value and sensitivity analysis about each design variable is also performed.
Journal of Engineering for Gas Turbines and Power, 2017
Gas foil bearings (GFBs) have many noticeable advantages over the conventional rigid gas bearings... more Gas foil bearings (GFBs) have many noticeable advantages over the conventional rigid gas bearings, such as frictional damping of the compliance structure and tolerance to the rotor misalignment, so they have been successfully adopted as the key element that makes possible oil-free turbomachinery. As the adoption of the GFB increases, one of the critical elements for its successful implementation is thermal management. Even though heat generation inside the GFB is small due to the low viscosity of the lubricant, many researchers have reported that the system might fail without an appropriate cooling mechanism. The objective of the current research is to demonstrate the reliability of GFBs installed in the hot section of a micro-gas turbine (MGT). For the cooling of the GFBs, we designed a secondary flow passage and thermohydrodynamic (THD) analysis has been done for temperature prediction. In the analysis, the 3D THD model for the radial GFB extended to include the surrounding struct...
Transactions of the Korean Institute of Electrical Engineers, 2008
【This paper presents the status of advanced technologies and domestic researches for development ... more 【This paper presents the status of advanced technologies and domestic researches for development of Korean next generation maglev. Generally, two specific configurations such as the EMS (Electromagnetic Suspension) with LSM (Linear Synchronous Motor) and EDS (Electrodynamic Suspension) with LSM can be employed as a propulsion and levitation device of high-speed maglev. Worldwide high-speed maglev developments refer to projects such as the German Transrapid with EMS, the Japanese MLX with EDS, and the U.S. Inductrack with PM (Permanent Magnet) EDS maglev system. In this paper, the propulsion and levitation systems of these world wide high-speed maglev have been reviewed and analysed.】
A web based automation of fatigue durability analysis for a welded bogie frame of railway vehicle... more A web based automation of fatigue durability analysis for a welded bogie frame of railway vehicle is realized with several kinds of system integration techniques. The macro program of I-DEAS, the APDL of ANSYS, and an in-house fatigue code are utilized for the parametric geometry modeling and automatic generation of finite element models, the static stress analysis, the fatigue durability analysis, respectively. A multi-agent based engineering framework is implemented on the JADE to integrate the overall process. All engineering programs are integrated by a XML based wrapper. A database to contain engineering data and web based user interfaces are also developed. A parametric study is carried out to take into account the effect of geometrical change of transom support brackets on its fatigue durability. Developed automation techniques reduce remarkably the time and costs required in the fatigue durability analysis.
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