SOFC阴极空气预热器耦合传热特性及参数影响分析

Coupled heat transfer characteristics and parameter influence analysis of SOFC cathode air preheater

针对固体氧化物燃料电池(SOFC)高温区碳化硅基阴极空气预热器这一新型换热设备,开展极高温工况下的烟气-空气的辐射-导热-对流耦合传热特性及参数影响分析,基于ANSYS Fluent采用DO模型分析高温气体辐射换热及气体吸收系数对换热器性能的影响,并与S2S模型及不考虑辐射换热模型的计算结果进行对比;同时研究了壁面发射率及烟气进口温度对耦合传热的影响规律。结果表明,烟气进口温度800~1100℃条件下,辐射换热的影响较大,但烟气吸收系数及气体辐射的影响可以忽略;壁面发射率、烟气入口温度对耦合传热的影响非常明显,壁面发射率和烟气入口温度越高,空气出口温度越高。研究结果可为碳化硅基阴极空气预热器的设计提供理论依据。

For the SiC-based cathodic air preheater,a novel SOFC high temperature heat exchanger,the coupled radiation-conduction-convection heat transfer and parameter influence characteristics between flue gas and air under extremely high temperature conditions were investigated.The DO model in ANSYS Fluent was utilized to analyze the effects of the radiation heat transfer and absorption coefficient of high-temperature flue gas on performance of the heat exchanger,and the simulation results were compared with the S2S model and non-radiation model.The effects of wall emissivity and flue gas inlet temperature on coupled heat transfer were also studied.The results show that when the flue gas inlet temperature is 800~1100℃,influence of radiation heat transfer is very important,but the effects of flue gas absorption coefficient and radiation can be ignored.Meanwhile,the effects of the wall emissivity and flue gas inlet temperature on the coupled heat transfer performance are very significant,the higher the wall emissivity and flue gas inlet temperature,the higher the outlet temperature of air.The research results can provide a theoretical basis for the design of silicon carbide based cathode air preheaters.