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

<sec>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 SOFC more than 700 ℃, so it should be preheated to startup (e.g. 600 ℃). induced gradient crucial factor that results the of SOFC, therefore there are many studies on optimization process.</sec><sec>Numerical model an important tool study process, however exists discrepancy between and experimental results. numerical always gives very high which can result crack according material permissible stress, this disagrees with practical result. In paper, hot gas developed verified comparing from literature. Then, location maximum distribution studied model, extremely at entrance analyzed. Some conclusions given below.</sec><sec>1) located edge nearby entrance. variation rise rate velocity show negligible effect position flow direction. For single channel method, dual cathode whatever feeding way co-flow counter-flow, because conductivity lowest.</sec><sec>2) There entrance, sharply decreases along flowing direction small section. may uniform inlet set greatly enhance heat transfer component due large difference section.</sec><sec>3) extension give fully reduce however, section temperature. Therefore, as criterion safety overestimate analyzed together optimize process.</sec>