Performance Analysis Of Proton Exchange Membrane Fuel Cell With Fractal Tree-like Flow Field

As the public attention focus on the environment, many new kinds of energy with low pollution gradually replaced the traditional one. Proton exchange membrane fuel cell as a kind of efficient and environmental friendly energy which developed quickly is widely used in submarine power energy, portable equipment and automotive fuel, etc.Flow field plate is an important part of proton exchange membrane fuel cell(PEMFC),mainly plays a role of transferring reaction gas, discharging the product. The geometric design of the flow field is the key factors for the performance of PEMFC. To improve the performance of the typical flow field, in this dissertation, the principle of bionics and tree fractal theory is introduced in the design of flow field. Based on flow field of tree fractal geometry, hope to be able to reduce the flow resistance in the typical flow field, improve the mass transfer characteristics of flow field, reduce the runtime outside of the proton exchange membrane fuel cell energy loss. The main work of this dissertation is as follows:1. The symmetric and asymmetric typical interdigitated flow fields which based on tree fractal of alternating refers to the typical interdigitated flow field, under the same operating conditions. Through the analysis of three kinds of flow fields about polarization curve, the hydrogen distribution, current density distribution and water heat distribution on proton exchange membrane, obtain that the asymmetric interdigitated flow tree based on tree fractal is better than the rest of the two kinds of flow field. Introducing geometric design of asymmetric tree fractal to parallel flow field design, and in the same operating conditions simulated the performance of the two kinds of parallel flow field, reach a conclusion asymmetrical geometric design to improve the performance of parallel flow field based on tree fractal effect is not obvious.2. Change the operating conditions of proton exchange membrane fuel cell, to improve its performance. Taking the asymmetric typical interdigitated flow fields which based on tree fractal for example, by changing its humidification conditions, working position, cathode oxidants type and mass flow to analyze proton exchange membrane fuel cell polarization curve and the change of the mass transfer characteristics, it is concluded the appropriate operation condition.3. Through the preparation of proton exchange membrane fuel cell with asymmetric typical interdigitated flow fields which based on tree fractal and test its basic performance,compared with the results from simulation, analyze the experimental data.The dissertation design and analysis based on tree fractal characteristics of the flow field,through experiment verification, concluded the rationality of the results.. Provides certain guiding significance to proton exchange membrane fuel cell flow field design and preparation.