Browsing by Author "Chen Junxun"

Now showing 1 - 2 of 2

Design and Performance Analysis of Micro Proton Exchange Membrane Fuel Cells
(2009-04-01)
Zhong Zhenzhong
;
Chen Junxun
;
Peng Ronggui
;
機械工程學系
;
Department of Mechanical Engineering
This study describes a novel micro proton exchange membrane fuel cell (PEMFC) (active area, 2.5 cm(2)). The flow field plate is manufactured by applying micro-electromechanical systems (MEMS) technology to silicon Substrates to etch flow channels without a gold-coating. Therefore, this investigation used MEMS technology for fabrication of a flow field plate and presents a novel fabrication procedure. Various operating parameters, such as fuel temperature and fuel stoichiometric flow rate, are tested to optimize micro PEMFC performance. A single micro PEMFC using MEMS technology reveals the ideal performance of the proposed fuel cell. The optimal power density approaches 232.75 mW.cm(-1) when the fuel cell is operated at ambient condition with humidified, heated fuel.
Enhancement of Proton Exchange Membrane Fuel Cell Performance Using a Novel Tapered Gas Channel
(2009-04-01)
Zhong Zhenzhong
;
Chen Junxun
;
Zhuang Pingji
;
機械工程學系
;
Department of Mechanical Engineering
Based on use of multi-dimensional models, this investigation simulates the performance of a proton exchange membrane fuel cell by varying the channel pattern. In the one-dimensional model, the porosity of the gas diffusion layer is 0.3. The model reveals the water vapor distribution of the fuel cell and demonstrates that the amount of water vapor increases linearly with the reduction reaction adjacent to the gas channel and the gas diffusion layer. Secondly, four novel tapered gas channels are Simulated by a two-dimensional model. The model considers the distributions of oxygen, the pressure drop, the amount of water vapor distribution and the polarization curves. The results indicate that as the channel depth decreases, the oxygen in the tapered gas channel can be accelerated and forced into the gas diffusion layer to improve the cell performance. The three-dimensional model is employed to simulate the phenomenon associated with four novel tapered gas channels. The results also show that the best performance is realized in the least tapered gas channel. Finally, an experimentally determined mechanism is found to be consistent with the results of the simulation.