| The fuel cell is an electrochemical power generation device with excellent performance,which can directly convert the chemical energy of the fuel into electrical energy.Among them,the solid oxide fuel cell(SOFC)has attracted more and more attention because of its high efficiency,cleanliness and diverse fuel forms.In the past decade,the performance and manufacturing technology of SOFC single cells have been greatly improved.It can basically meet the commercial needs,however,how to maintain the high performance of the battery cells while stacking the cells into the stack and how to extend the life of the stack are still two major obstacles on the road to the commercialization of fuel cell technology.Therefore,in addition to further exploring new materials,the development of the theoretical system for SOFC stack analysis and optimization design is very important for the sustainable development of fuel cell technology.(1)First,a 3D large-scale hydrodynamic model was established for the air and fuel flow channels in a 20-layer flat-plate SOFC stack with different geometric parameters of power ranging from 0.5 to 1.5 k W for comparison and optimization The air / fuel flow distribution quality between the stack layers and the ribs on each layer.The performance of the stack is measured using the stack uniformity index г,the stack pressure drop at the entrance and exit Δp,and the standard deviation factor бc of the gas mass flow in the rib.The effects of various geometric parameters,such as the type of manifold layout,the radius of the intake / exhaust manifold and the width of the intake / exhaust header,on the quality of the flow distribution between the layers of the stack and the ribs of each layer were studied in this paper,and the relevant structure was given Recommendations for optimization of geometric parameters.(2)Secondly,basing on the above theory,a new type of SOFC stack design scheme is proposed.The air flow path and fuel flow path adopt different structural types,that is,the air flow path adopts a flow path with a discrete cylindrical structure.The fuel flow path uses parallel serpentine flow paths.Using a 24-layer battery stack as an example,a three-dimensional large-scale multi-physics coupling numerical analysis model was established to evaluate the distribution characteristics and quality of various physical fields within the design,from the interlayer flow distribution,the overall temperature,and the concentration of the cell surface temperature component concentration The distribution and other aspects prove that the design scheme of the SOFC stack with this new structure hasgood performance and is worth further optimization and development.(3)Finally,basing on the above model structure,we have further optimized the above battery stack design,and proposed a new SOFC battery stack structure design scheme with cross-,co-and convective flow characteristics.In this solution,the battery stack has two independent air flow channel groups,and the connection plates of the even-numbered stack can be obtained by rotating the connection plates of the odd-numbered layers by 180 degrees along the Z axis.For this structure,a 3D large-scale multiphysics coupled 24-layer stack model was analyzed and calculated to prove that compared with the above model,this kind of fuel cell stack with integrated flow characteristics of cross flow-parallel flow-convection does indeed have more For excellent performance. |
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