• 한국수소및신에너지학회논문집
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• 제28권5호
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• pp.492-501
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• 2017

A 900 W scale direct methanol fuel cell (DMFC) stack is designed and fabricated for unmanned aerial vehicle (UAV) applications. To meet the volume and weight requirements, metallic bipolar plates are applied to the DMFC stack for the first time wherein POS470FC was chosen as bipolar plate material. To ensure good robustness of the metallic bipolar plate based DMFC stack, finite element method based simulations are conducted using a commercial ANSYS Fluent software. The stress buildup and deformation characteristics on bipolar plates and end plates are analyzed in details. The present DMFC stack exhibits the performance of 1,130 W at 32 V and 35.3 A, clearly demonstrating that it could successfully operate for UAVs requiring around 1,000 W of power.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 춘계학술대회 논문집
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• pp.1023-1024
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• 2010

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2009년도 춘계학술대회 논문집
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• pp.667-668
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• 2009

• 한국자동차공학회논문집
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• 제18권5호
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• pp.68-75
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• 2010

The one of the major problems in the development of PEMFC was regarding to the assurance of sealing on stack. The failure on the sealing creates the problems of fuel leakage, mixing, internal combustion, damage on parts and can be a direct reason for the degrading the efficiency of fuel cell. This paper studies on the analytical approach for improving the contacting pressure distribution on the gasket at the evaluation on the sealing of fuel cell stack. So, the assembly analysis on multi layered fuel cell stack was performed. The research on the simplification of finite element model was performed for three dimensional analysis at the multi layered state. The improved contact pressure distribution was obtained through the case studies on gasket for better sealing. In addition, the number of the cell was determined for the effective analysis and the structural characteristics were evaluated based on this research.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2000년도 추계학술대회 논문집
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• pp.84-89
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• 2000

Thermal simulation of typical stack-type and newly proposed planar-type micro-gas sensors were studied by FEM method. The thermal analyses for the proposed planar structure including temperatur distribution over the sensing layer and power consumption of the heater were carried using finite element method by computer simulation and well compared with those of typical stack-type micro-gas sensor. The thermal properties of the microsensor from thermal simulation were compared with those of a actual device to investigate the acceptability of the computer simulation.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 ITC-CSCC -2
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• pp.623-626
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• 2000

The purpose of this paper is to find an efficient solution for multiple constant multiplication (MCM) problem. Since the circuit structure can be represented as a directed acyclic graph, evolutionary computing is considered as an effective tool for optimization of circuit synthesis. In this paper, we propose a stack type operator as a chromosome element to synthesize a directed acyclic graph efficiently. This type of chromosome can represent a graph structure with a set of simple symbols and so we can employ the similar method to a conventional GA.

• 한국소음진동공학회논문집
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• 제16권7호
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• pp.739-745
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• 2006

This paper presents a novel type of hybrid dispensing head for IC fabrication and surface mount technology. The proposed mechanism consists of solenoid valve and piezoelectric stack as actuators, and provides positive-displacement and jet dispensing. The positive-displacement dispensing can produce desired adhesive amount without viscosity effect, while the jet dispensing can produce high precision adhesive amount. In order to determine the relationship between required voltage of the piezoelectric actuator and needle displacement, both static and dynamic analysis are undertaken, In addition, finite element analysis is performed in order to find optimal design parameters. Dispensing flow rate and pressure in the chamber are evaluated through fluid dynamic model.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 춘계학술대회논문집
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• pp.821-826
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• 2006

This paper presents a novel type of hybrid dispensing head for IC fabrication and surface mount technology. The proposed mechanism consists of solenoid valve and piezoelectric stack as actuators, and provides positive-displacement and jet dispensing. The positive-displacement dispensing can produce desired adhesive amount without viscosity effect, while the jet dispensing can produce high precision adhesive amount. In order to determine the relationship between required voltage of the piezo actuator and needle displacement, both static and dynamic analysis are undertaken, In addition, finite element analysis is performed in order to find optimal design parameters. Dispensing flow rate and pressure in the chamber are evaluated through fluid dynamic model.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제54권8호
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• pp.358-363
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• 2005

This paper presents the reasonable design parameters of a switched reluctance motor to drive a hybrid electric vehicle by using the equivalent magnetic circuit method. The designed motor can be redesigned by using finite element analysis as a variation of the parameter for the purpose of improving performance. This paper shows that a flat-topped current of a phase can be made from a change of the lamination stack length for high average torque and a lower torque ripple. The change of current falling time as a variation of turn-off angle was shown by finite element analysis. The core loss and copper loss were described. The torque of the redesigned motor is suitable for low and high speed ranges to drive a HEV. which is verified by the speed-torque curve.

• 한국수소및신에너지학회논문집
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• 제23권5호
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• pp.468-475
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• 2012

A proper stacking force and assembly are important to the performance of fuel cell. Improper assembly pressure may lead to leakage of fuels and high interfacial contact resistance, excessive assembly pressure may result in damage to the gas diffusion layer and other components. The pressure distribution of gas diffusion layer is important to make interfacial contact resistance less for stack performance. To analyze the influence of design parameter factors for pressure distribution, and to optimize stack design, DOE (Design of Experiment) was used for polymer electrolyte membrane fuel cell stack pressure test. As commonly known, the higher clamping force improves the fuel cell stack performance. However, non-uniformity of stress distribution is also increased. It shows that optimization between clamping force and stress distribution is needed for well designed structure of fuel cell stack. In this study, stack design optimization method is suggested by using FEM (Finite Element Methode) and DOE for light-weighted fuel cell stack.