Three-dimensional Numerical Simulation Of Solid Oxide Fuel Cell Based On Foam Flow Field

Due to the declining global fossil fuels and the increasing greenhouse effect,hightemperature solid oxide fuel cells(SOFC)have been widely used as one of the most promising power generation technologies in order to reduce the use of fossil fuels and their negative impact on the environment.attention.Due to the high operating temperature(400-1000 ℃),solid oxide fuel cell(SOFC)enables direct internal reforming of most hydrocarbon fuels in the anode thus is high fuel flexible.SOFC also has the advantages of high efficiency and low emissions.Therefore,it is of great significance for the performance optimization study of SOFC.Firstly,the anode-supported SOFC is selected as the research object,and a comprehensive three-dimensional model based on flat-planar SOFC is established.Considering the mass transfer and heat transfer process such as internal reforming reaction,electrochemical reaction and multi-component diffusion,the internal multiphysics of SOFC are further studied.Metal foam is proposed to replace the conventional straight channel at cathode and the two flow distributors will be compared in detail.Then,a single-channel model of the anode-supported SOFC is conducted to compare the two cathode flow distributors.The study determines the main physical parameters of the metal foam used and points out that an appropriate permeability coefficient is beneficial for the fuel cell performance improvement.And the performance and various influencing factors of the two cathode flow distributors are compared.The results show that the anode-supported SOFC can greatly improve the cell performance by using the metal foam at the cathode,but it is more susceptible to fuel utilization and air stoichiometry.The application of metal foam enhances the mass transfer conductivity of the flow field and reduces the concentration loss and ohmic losses.The study also indicates that the optimal cathode diffusion layer thickness of the SOFC with the conventional flow channel is about 300 μm.But for a SOFC with metal foam in cathode,the thinner the cathode diffusion layer thickness offers better performance.Since the cathode of the anode-supported SOFC is generally very thin,which indicates that the metal foam is suitable as a cathode gas distributor for the anodesupported SOFC.Finally,in order to deeply explore and analyze the multi-physics distribution inside SOFC,the study uses a multi-channel single cell model for simulation comparison.It is found that when the cathode adopts foam flow field,a more uniform velocity field distribution is obtained,and the influence of the inlet design on the flow field is reduced;a more uniform oxygen distribution and a cathodic electrochemical reaction rate distribution can also be obtained,which solved the problem of lower oxygen concentration and reaction rate under rib area of the parallel flow field.Due to the uniform transmission of electrons,the electrochemical reaction distribution is uniform,which reduces the ohmic heat and reduces the overall temperature by 35 ° C.The methane steam reforming reaction distribution is no longer concentrated in the inlet area and the distribution is more uniform,the anode component is also affected and the performance has been improved significantly.