Simulation And Optimization Of Gas Field In Proton Exchange Membrane Fuel Cell

To resolve the increasing contradictions among economic development, environmental protection and lacking of energy resources, it has become an urgent job to develop clean and efficient new energy resources technology, which is the strategy of sustainable development of human society. The proton exchange membrane fuel cell(PEMFC) has some advantages, such as low noise, zero pollution, without erode, long lifetime, high power density, high efficiency, safety, stability and so on. Consequently it is the hotspot of new energy resources and power technology development in the twenty-first century.The gas field in PEMFC means the gas distribution in gas source, gas inlet tube(scale of m), gas-blower, gas manifold(scale of cm), channel(scale of mm), diffusion layer(scale of um), hydrophobic layer and catalyst layer(scale of nm). The aim of changing the scales is to make oxygen reach reaction area as evenly as possible. They are connected with each other and wholly affect the results of the oxygen distribution in catalyst layer. When the air is fed to cathode of PEMFC, the oxygen concentration decreases along the channel because of reaction, and the oxygen distribution is affected by land of the flow plate. So the oxygen distribution is uneven on cathode side and leads to dropping of cell performance. Hence it is becoming one of the basic PEMFC design jobs to improve the even distribution and the concentration of oxygen on cathode side.The analysis model and design methodology for the gas field are discussed referring to related documents. The structure parameters of gas manifold, channel, diffusion layer and hydrophobic layer which affect the oxygen distribution are also studied. The result shows that multiple inlet is better than single inlet, and that inlet with buffer is better than that without buffer. Other optimal design structures are also adopted. The gas manifold with optimal structure make oxygen much evener for each cell. When the width of the channel is unchangeable, the more are the numbers of the channels, the narrower thechannel becomes, the evener the oxygen on the surface of diffusion layer becomes. The more is diffusion resistance, the less the oxygen quantity is. The even degree going through the diffusion layer and hydrophobic layer depends on relative change of diffusion resistance in crosswise and lengthways. If the diffusion resistance in crosswise is bigger, it will not benefit the oxygen distribution. The function of diffusion layer and hydrophobic layer is affected by channel and depends on the pore diameter, the porosity and the thickness of diffusion layer and catalyst layer.Simulation and optimization of the gas field in PEMFC numerically simulate mass transfer processing, which gives a scientific guide to the gas field optimization design and will be applied widely in the progress of PEMFC design.