| High temperature proton exchange membrane fuel cell(HT-PEMFC)is a kind of efficient and clean energy conversion device.The flow channel in HT-PEMFC plays the role of transporting reaction gas and discharging reaction products.Excellent flow channel design can effectively ensure the reaction gas supply at the catalyst layer,reduce the flow channel pressure drop,thus improving the performance of the battery.The anode fuel for HT-PEMFC is usually pure hydrogen.At this point,the battery does not pollute the environment,but it faces problems in transporting and storing hydrogen.The transport and storage of hydrogen can be avoided by directly feeding the reforming gas into the proton exchange membrane fuel cell.In this paper,Comsol Multiphysics simulation software was used to establish a three-dimensional steady-state model of HT-PEMFC working process,and the operation of HT-PEMFC with different flow channel types was studied when pure hydrogen and reformed gas were imported.The influence of reforming air intake on HT-PEMFC operation was compared with the advantages and disadvantages of different flow channels.First,the simulation analysis of HT-PEMFC under the condition of anode pure hydrogen gas feed is carried out.Through the simulation analysis of four traditional flow channels,it is found that from the perspective of cathode gas distribution and battery current density,at 0.75 V operating voltage,the performance of single-channel serpentine flow channel is better than that of interdigital flow channel,double-channel flow channel Spiral and parallel flow channels.At low operating voltage,due to the double helical flow channel has two gas inlets,the reaction gas in the diffusion layer of the battery is more abundant,but there is a gas "short circuit" problem in the flow channel.As far as the pressure drop of the flow channel is concerned,the single serpentine flow channel > the double helical flow channel > the interdigital flow channel > the parallel flow channel.Then,through the numerical analysis of the multi-channel serpentine flow channel,it is found that by increasing the number of serpentine flow channels(shortening the flow channel length),the pressure drop of the flow channel can be significantly reduced,and the concentration of the reactants at the catalyst layer can be increased,thereby improving the battery performance.When the number of serpentine flow channels is small,increasing the number of flow channels can improve the battery performance more obviously.After changing the "fuel" of the anode to reformed gas(CH3OH+H2O →3H2+CO2),the numerical analysis of the cell shows that the pressure drop of the anode flow channel is significantly higher than that of pure hydrogen.The maximum power density of the battery is also reduced when compared to pure hydrogen intake.The highest power density of single serpentine flow channel HT-PEMFC,interdigitated flow channel HT-PEMFC,parallel flow channel HT-PEMFC,and double spiral flow channel HT-PEMFC decreased by 9.95%,8.29%,8.55%,3.98%,respectively.The simulation of multi-channel serpentine flow channels shows that when the number of serpentine flow channels is small,increasing the number of serpentine flow channels can improve the battery performance more obviously than when pure hydrogen gas is introduced.The same as when pure hydrogen is introduced,the more the number of serpentine flow channels,the less obvious the improvement of battery performance will be when increasing the number of flow channels.Through the numerical analysis of the three new bionic flow channels,it is found that the leaf-shaped flow channel(II)is better than the leaf-shaped flow channel(Ⅰ)and the lung-shaped flow channel in terms of the distribution of oxygen concentration and the maximum power density of the battery.The pressure drop of the three runners is not much different.The maximum power density of leaf shaped channel(II)HT-PEMFC decreases the most when the anode inlet is reforming gas. |
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