| Summary: | 碩士 === 華梵大學 === 機電工程研究所 === 92 === The purpose of this thesis is to establish a two dimensional PEM fuel cell model. The main objective is to examine the influence of inlet fuel humidity on the mass transport and the cell performance, and to emphasize the effectiveness of interdigitated flow field by increasing the numbers and position of the baffles in the flow channel. In the section of results and discussion, the distributions of the local current density, fuel flux and water vapor are well examined under different operating conditions.
The effects of inlet fuel humidity reveal that the performance is enhanced with an increase in inlet fuel humidity on the anode side. But on the cathode side, the better cell performance is noted for lower inlet fuel humidity. For the operating condition of voltage being larger than 0.7V, the effects of liquid water on the cell performance and reactant gas transfer can be neglected. Besides, for the low operating conditions, the cell performance increases with an increase in the inlet fuel velocity at the cathode side. However, increasing the numbers of baffles in the flow field, which means to expand the area of force convection and to increase the transport rate of oxygen in fuel at the same time, therefore, results in the improvement of the cell performance. When the baffle is located at the downstream of flow channel, it makes the area of diffusion at the upstream larger. By controlling the mechanism of the force convection, the PEMFC with baffle effect can retard the mass transport losses.
|
|---|
