多层墙体内部湿迁移对传热的影响

Effects of Moisture Transfer on Heat Transmission of Multilayer Wall

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 moisture transfer within the wall have an important impact on the hygrothermal performance of building envelope, energy consumption and indoor environment. The paper established onedimensional,unsteady,heat,Air and Moisture transfer（ HAM） model within the multilayer wall with relative humidity and temperature as the driving force. The paper uses the finite element method for numerical solution and focuses on the mechanism of the effect of moisture transfer on heat transfer. The numerical results show that the higher transformation rate is,the higher the wet density is with the consideration of the moisture transfer; moisture would be accumulated in wall; the moisture transfer is dominated mainly by vapor diffusion and liquid conduction;moisture transfer has a great effect on the average number of the wall; the effect of phase change on heat transfer cannot be neglected.