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墙体的传热传质对建筑围护结构的热工性能、建筑能耗和室内环境有着十分重要的影响。本文以相对湿度和温度为驱动势建立多层墙体一维非稳态热湿空气耦合传递模型(HAM模型),并利用有限元法进行了数值求解,重点关注了湿迁移对传热的影响机理。研究结果表明:考虑传湿时墙体内外壁面附近出湿度梯度大,相变速率大,湿流密度大;墙体内部会产生湿积累;墙体内部湿迁移主要受蒸汽扩散主导,墙体交界面处局部Nu数变化受湿迁移的影响大;相变过程对传热的影响不可以忽略。
The heat and mass transfer of the wall has a very important influence on the thermal performance, building energy consumption and indoor environment of the building envelope. In this paper, a one-dimensional unsteady thermo-hygrothermal air-coupled transmission model (HAM model) for multi-story wall is established based on the relative humidity and temperature. The finite element method is used to solve the problem. The focus is on the influence of wet migration on heat transfer mechanism. The results show that, considering the high humidity gradient, the rate of phase transition is high and the wet flow density is high near the inner and outer walls of the wall; the wet accumulation inside the wall is mainly caused by the diffusion of steam; The change of local Nu number at the interface is greatly affected by wet migration. The influence of phase transition on heat transfer can not be neglected.