Performance Simulation Analysis Of HT-PEMFC Based On Wavy Flow Channel

PEMFC has become one of the most widely used and practical fuel cells due to its fast cold start and environmental friendness.However,PEMFC also has some disadvantages,such as complex flooding and high requirements on the working environment,and the most effective measure to solve these problems is to improve the working temperature of PEMFC.Therefore,many researchers have shifted their focus to develop HT-PEMFC.The precondition for HT-PEMFC to operate smoothly is that the electrodes in the reaction process should obtain enough reaction gas and the accumulated water in the battery can be discharged smoothly in time.Improving the flow channel structure is one of the methods to solve this problem and improve the mass transfer performance of HT-PEMFC.Therefore,this paper designed a new wavy flow channel structure based on the ordinary straight flow channel.Based on the principles of thermodynamics,molecular dynamics and electrochemistry,a three-dimensional,two-phase,constant temperature and steady state model of HT-PEMFC is built by numerical simulation method.The simulation data and experimental data are compared to verify the effectiveness of the model.The physical fields of dense material transfer and secondary current distribution are added into the flow field model,and the performance of HT-PEMFC is analyzed by using the finite element method.In this paper,the influence of wavy flow channel structure on mass transfer and current density of HT-PEMFC is studied.Wavy flow channel structure will subduct the fluid in the flow channel,so that the reactants and products in the flow channel form a partial velocity in the horizontal and vertical directions that is conducive to material transmission,and at the same time,it is conducive to the downward diffusion of reaction gas to participate in the electrochemical reaction,which can accelerate the rapid discharge of water generated in the reaction.The factors that influence the performance of fuel cell are the number of waves,the length and the height of waves.The results of the influence of the number of waves on the performance of HT-PEMFC show that with the increase of the number of waves,the oxygen concentration in GDL gradually increases,the water concentration gradually decreases,the average current density in the battery also increases,and the performance of the battery gradually improves.The results show that with the increase of the wavy length,the oxygen concentration in GDL gradually increases,the water concentration gradually decreases,the average current density in the battery has a small increase,the battery performance has a small increase.The results of the influence of the wavy height on HT-PEMFC performance show that when the wavy height is 0.03 cm,the battery performance reaches the best state.When the wave reaches the bottom,although the battery performance is greatly improved,the wavy flow field plate is in contact with the GDL,and long-term use will cause damage to the GDL.Therefore,such flow channel structure has both advantages and disadvantages.On this basis,this paper designs the gradient wavy flow channel to study its internal mass transfer and current density.The simulation results show that compared gradual wavy flow channel structure with the wave height of 0.03 cm,the performance of the battery is improved.