摘要
对于半周受热的超临界锅炉膜式水冷壁,管内工质温度和对流换热系数的周向分布具有较强的不均匀性。文中选取SST k-ω湍流模型,在使用实验数据校验了模型后,对半周受热的鳍片管内超临界水的换热和通过管壁的导热进行耦合计算。计算结果表明在拟临界区外,工质温度和换热系数的周向不均匀性对壁温分布的影响很明显;在拟临界区内,周向不均匀性的影响则可忽略。采用周向均匀假设进行简化计算时,换热系数应该选取向火侧中点处的值,这样能保证在拟临界区内、外都能准确地预测向火侧的温度场以及危险点的位置和温度。此外,结果还表明可以使用基于全周加热实验数据得到的换热关联式和水动力计算标准JB/Z201-83来预测危险点的壁温,计算偏差在±10K以内。
Flow of supercritical water（SCW） is circumferentially non-uniform in the water wall of SCW boilers where heat is input on one side. To study the effect of inner flow non-uniformity（fluid temperature, heat transfer coefficient） on the temperature distribution of water wall, the SST κ-ω turbulence model was employed to solve conjugate heat transfer between tube wall and SCW. After validating the model against experimental data, computational tests were performed in a membrane tube. Results show that circumferential non-uniformity has significant effect on wall temperature distribution in the region away from pseudocritical point, while this impact can be neglected within the pseudocritical region. Heat transfer coefficient at the midpoint of hot-side inner wall, αcp, is recommended to be adopted when one uses circumferential uniform assumption （T=Tb, a=αcp）. Under this assumption, the position and value of maximum wall temperature can be accurately predicted in regions near and away from pseudocritical point. Besides, it is found that together with JB/Z201-83, Nusselt correlations based on uniformly-heated data can be used to predict the maximum wall temperature of membrane tube, with a deviation less than ±10K.
出处
《中国电机工程学报》
EI
CSCD
北大核心
2015年第5期1153-1160,共8页
Proceedings of the CSEE
基金
国家科技支撑计划项目(2012BAA12B02-01)
中国科学院战略先导科技专项(XDA07030100)~~
关键词
超临界锅炉
膜式水冷壁
流动周向不均匀性
壁温分布
危险点
supercritical pressure boiler
membrane waterwall
.circumferential flow non-uniformity
wall temperature distribution
maximum wall temperature
