Solid Oxide Fuel Cell Gas Distribution Characteristics And Multiphysics Coupling Simulation

In today’s energy development,fuel cells are widely concerned in the world because of their advantages such as cleanness,no pollution,and high energy conversion rate.Similarly,among many types of fuel cells,solid oxide fuel cells(SOFC)have high voltage and power density and excellent portability,which are favored by countries around the world.Therefore,the research on solid oxide fuel cells is particularly important.Because the reaction mechanism of the fuel cell is relatively complicated during the working process,it involves the coupling of multiple processes such as material transfer,momentum conversion,and energy exchange.The application of experiments to study the related mechanism is extremely tough,costly,and the experiment period is too long.Therefore,this paper will use the method of numerical simulation to study the relevant characteristics of solid oxide fuel cells.This article mainly studies the following two parts: First,the first part is based on FLUENT to study the distribution of the velocity field,pressure field and temperature field of the gas in the air side and fuel side air channel of the flat SOFC stack in the original structure,the structure with semicircular sub-pipes,and the structure with additional sub-pipes,and obtain the maximum flow distribution of each sub-air channel corresponding to the three structures,and then further change the ratio of the number of main pipelines at the inlet and outlet of the fuel side cell stack to obtain the corresponding three field distribution and sub-air channel flow distribution.By comparing the calculation results under different airway arrangements,it is found that the speed distribution of the battery stack structure with additional sub-pipes and the ratio of the number of main pipelines at the inlet and outlet that is 1:2 is more uniform,the pressure is smaller,the local high temperature area is less,and the flow distribution of the sub airway is more uniform.The second part is based on COMSOL to study the effect of changing the structural parameters of porous electrode such as porosity,tortuosity factor,and different flow directions on the cell performance(voltage,power density,fuel utilization rate)and concentration distribution under the structure of the SOFC single cell.It can be found by comparison that the larger the porosity and the smaller the tortuous factor,the better the performance of the battery.When the fuel flow direction in the air channel is the same as the air flow direction,it is also conducive to improving the performance of the battery.The gas concentration is also more evenly distributed in the electrode.The practical significance of this study is that it can provide some guidance for the design of the stack structure and the arrangement of related structural parameters in the preparation process of the porous electrode,which can improve the performance of the battery and extend the life of the battery.