Study On Heat And Mass Transfer And Flow Field Structures Of Proton Exchange Membrane Electrolysis Cell

In recent years,hydrogen energy has received widespread attention from countries all over the world.Hydrogen has high calorific value and low pollution.It can be utilized in various fields such as transportation,industry,and medicine.Proton exchange membrane electrolysis cell(PEMEC)is a new device for hydrogen production,which can convert water into high-purity hydrogen and oxygen by electrolysis cells.During the operation of the electrolysis cell,the electrochemical reaction,the mass transfer of the porous medium and the heat transfer of the solid,fluid and porous medium are also involved in.Effectively improve the stable operation capacity and life of proton exchange membrane electrolysis cell can be achieved by improving the performance of heat and mass transfer inside the electrolysis cell.Based on the working principle of the proton exchange membrane electrolysis cell,an experimental system has been built to test the polarization performance and temperature distribution of the electrolysis cell during operation.Comparing the water supply only on the anode side and the water supply both on the anode and cathode sides,it is found that There is almost no difference in the polarization curves,but when the cathode side is supplied with water,the temperature of the electrolysis cell is significantly reduced.It is difficult to observe the mass transfer or heat transfer in the porous area and the proton exchange membrane of the electrolysis cell through experimental means.Therefore,we have established a three-dimensional,two-phase model of a proton exchange membrane electrolysis cell.By coupling the electrochemical reaction,the transmission of gas and liquid in the electrolysis cell and the heat transfer process during the operation of the electrolytic cell,the effects of operating conditions and flow field design on the heat and mass transfer in the electrolysis cell are analyzed,and the structure size of the flow channel is optimized.The numerical simulation results of the single-channel electrolysis cell show that the increase of the initial temperature and the current density during the operation of the electrolysis cell will increase the temperature rise of the electrolysis cell.When the anode and cathode liquid water flow in reverse,the lowest temperature is observed in the electrolysis cell,but a higher temperature gradient is also observed on the proton exchange membrane.We also analyze the performance of the electrolysis cell under different sizes of the flow channel.The electrolysis cell has better performance of heat and mass transfer when the depth of the flow channel is 1.8 mm,and the width of the flow channel is close to the width of the ridge.In addition,the additional resistance blocks in the traditional smooth channel has a better effect of strengthening the mass transfer in the electrolysis cell,and the performance of heat transfer has been effectively improved.The simulation results of a single channel can not fully reflect the transmission characteristics of the entire flow field of electrolysis cell,this paper establishes a fullscale model of electrolysis cell and analyze the electrochemical performance,water and heat transfer characteristics and dynamic characteristics of electrolysis cell when external conditions are changed of electrolysis cells with parallel flow field,serpentine flow field and interdigitated flow field.The results show that the interdigitated flow field electrolysis cell has better mass transfer characteristics,lower and more uniform temperature compared with the parallel flow field and the serpentine flow field electrolysis cell,and its performance under dynamic conditions is better than the other two electrolysis cells.