固体氧化物燃料电池温升模拟中入口异常高温度梯度研究  

Study on extremely high temperature gradient at entrance of solid oxide fuel cell by preheating model

作　　者：申双林 张小坤 万兴文 郑克晴 凌意瀚 王绍荣[3] Shen Shuang-Lin;Zhang Xiao-Kun;Wan Xing-Wen;Zheng Ke-Qing;Ling Yi-Han;Wang Shao-Rong(School of Low-Carbon Energy and Power Engineering,China University of Mining and Technology,Xuzhou 221116,China;School of Materials Science and Physics,China University of Mining and Technology,Xuzhou 221116,China;School of Chemical Engineering and Technology,China University of Mining and Technology,Xuzhou 221116,China)

机构地区：[1]中国矿业大学,低碳能源与动力工程学院,徐州221116 [2]中国矿业大学,材料与物理学院,徐州221116 [3]中国矿业大学,化工学院,徐州221116

出　　处：《物理学报》2022年第16期224-232,共9页Acta Physica Sinica

基　　金：国家自然科学基金重点项目(批准号:51836004)和国家自然科学基金联合基金(批准号:U2005215)资助的课题。

摘　　要：针对固体氧化物燃料电池热循环失效问题,建立了固体氧化物燃料电池热气体预热动态模型,研究了电池内最大温度梯度分布规律和入口异常高温度梯度形成的原因,结果表明:在热气体参数和预热方式变化时,电池内最大温度梯度始终处于电池入口边缘处的电极表面;电池入口处存在异常高的温度梯度,且在入口一小段区域内,温度梯度沿流动方向迅速下降;其原因是模型中入口采用均一的平均速度和温度,“入口效应”强化气体与电池换热;采用入口段延长的方式可使入口速度充分发展,降低电池内最大温度梯度,但由于均一温度入口并未优化,入口处仍然存在很大的温度梯度和温度梯度变化;因此采用数值模拟研究电池预热升温安全性时,仅采用最大温度梯度作为安全性判据会高估电池内热应力.The degradation or failure caused by thermal stress is a serious problem for solid oxide fuel cell(SOFC),especially in preheating process.The common working temperature for SOFC is more than 700℃,so it should be preheated to startup temperature(e.g.600 ℃).The thermal stress induced by temperature gradient in SOFC is a crucial factor that results in the degradation or failure of SOFC,therefore there are many studies on the optimization of preheating process.Numerical model is an important tool in the study of SOFC preheating process,however there exists a serious discrepancy between the model results and experimental results.The numerical model always gives a very high temperature gradient in the SOFC which can result in SOFC crack according to the material permissible stress,and this result disagrees with the practical experimental result.In this paper,a hot gas preheating model of SOFC is developed and the model is verified by comparing with model results from the literature.Then,the location of maximum temperature gradient and distribution of temperature gradient in the SOFC are studied by this model,and the extremely high temperature gradient at entrance is analyzed.Some conclusions are given below.1) The maximum temperature gradient is always located at the edge of SOFC nearby the gas entrance.The variation of temperature rise rate and velocity of hot gas show negligible effect on the position of maximum temperature gradient in the gas flow direction.For single channel preheating method,the maximum temperature gradient is at the gas entrance.For the dual channel preheating method,the maximum temperature gradient is always at the cathode gas entrance whatever gas feeding way is co-flow or counter-flow,because the thermal conductivity of cathode is lowest.2) There is an extremely high temperature gradient at the gas entrance,and the temperature gradient sharply decreases along the gas flowing direction at the small entrance section.The extremely high temperature gradient may result from the uniform inlet te

关 键 词：固体氧化物燃料电池 温度梯度 数值模拟 入口效应 

分 类 号：TM911.4[电气工程—电力电子与电力传动]