Browsing by Author "Chu, H. S."

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Reactant gas transport and cell performance of proton exchange membrane fuel cells with tapered flow field design
(2006-07-14)
Liu, H. C.
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Yan, W. M.
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Soong, C. Y.
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Chen, Falin
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Chu, H. S.
The objective of this work is to examine the reactant gas transport and the cell performance of a proton exchange membrane fuel cell (PEMFC) with a tapered flow channel design. It is expected that, with the reduction in the channel depth along the streamwise direction, the reactant fuel gas in the tapered channel can be accelerated as well as forced into the gas diffuser layer to enhance the electrochemical reaction and thus augment the cell performance. The effects of liquid water formation on the reactant gas transport are taken into account in the present study. Numerical predictions show that the cell performance can be enhanced with the fuel channel tapered, and the enhancement is more noticeable at a lower voltage. The results also reveal that the liquid water effect in general influences the cell performance and the effect becomes significant at lower voltages. (c) 2005 Elsevier B.V. All rights reserved.
The effects of PE additive on the performance of polystyrene vacuum insulation panels
(2009-06-01)
Tseng, P. C.
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Chu, H. S.
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機械工程學系
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Department of Mechanical Engineering
The effects of adding polyethylene (PE) in polystyrene (PS) foaming material on the cell structure and the heat transfer of vacuum insulation panels (VIPs) are examined in this study. Several parameters are proposed to describe the foam structure, namely, the broken cell ratio, the average cell size and the solid volume fraction. Adding 2% PE was effective in altering the cell structure and reducing the heat transfer, while adding 5% PE did not improve the performance further. The lowest thermal conductivity found in this study is 4.4 mW m(-1) K(-1), which is among the best published performances of VIP. (C) 2009 Elsevier Ltd. All rights reserved.
Transient behavior of CO poisoning of the anode catalyst layer of a PEM fuel cell
(2006-09-22)
Chu, H. S.
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Wang, C. P.
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Liao, W. C.
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Yan, W. M.
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機械工程學系
A one-dimensional transient mathematical model is applied to simulate the carbon monoxide poisoning effect on the performance of a PEM fuel cell. Based on the CO kinetic model developed by Springer et al. [T.E. Springer, T. Rockward, T.A. Zawodzinski, S. Gottesfeld, J. Electrochem. Soc. 148 (2001) A11-A23], the transient behaviors of the CO poisoning process across the anode catalyst layer is investigated. The results show that the hydrogen coverage, OH, decreases with the time due to CO adsorption on the catalyst sites. A higher CO concentration results in fewer available catalyst sites for hydrogen electro-oxidation and a significant decrease in the response time to reach steady state, t(ss). Increasing the anode overpotential and the gas porosity would result in an increase in the current density, especially at low levels of CO concentration. (c) 2006 Elsevier B.V. All rights reserved.