Coupled Heat Transfer Characteristics of SiC High Temperature Heat Exchanger in Solid Oxide Fuel Cell

High temperature heat exchanger is a crucial equipment in the BOP of SOFC. Replacing the commonly used metal materials with high-temperature resistant SiC ceramic materials for the manufacturing of SOFC high-temperature heat exchanger is a revolutionary technology with great application potential. This paper focused on SiC-based cathodic air preheater which is a novel SOFC high temperature heat exchanger, and firstly investigated the coupled radiation-conduction-convection heat transfer characteristics between flue gas and air at extremely high temperature conditions. The DO model in ANSYS Fluent was utilized to analyze the radiation heat transfer characteristics of high-temperature flue gas and the effect of gas absorption coefficient, and the simulation results were compared with the S2S model and non-radiation model. The results showed that radiation heat transfer cannot be ignored at high flue gas inlet temperature. With flue gas inlet temperature in the range of 800–1100 °C and low air/flue gas flow rate ratio, the gas radiation heat transfer and the effect of flue gas absorption coefficient can be ignored.