三相水分共存的多层墙体热湿耦合传递模型

Mathematical Model of Coupled Heat and Moisture Transfer for Multilayer Wall with Three-Phase Moisture

考虑水分升华、凝华、气液和固液相变,以温度和水蒸气分压力为驱动势建立了气、液、固三相水分共存的多层墙体热湿耦合传递模型.构建了1面500mm(长)×450mm(高)×240mm(厚)试验墙体,利用恒温恒湿箱试验测试了箱体温度范围为常温^-33.94℃时墙体内部温度和平衡相对湿度的变化,分析了水分固液相变过程的特征,并对热湿耦合传递模型数值模拟计算结果的正确性进行了验证.结果表明:试验墙体内部温度和水蒸气分压力数值模拟计算结果和实测结果变化趋势相同,具有良好的一致性,各点温度数值模拟计算结果的最大相对误差为1.68%,平均相对误差为0.44%;水蒸气分压力数值模拟计算结果的最大相对误差为27.92%,平均相对误差为13.50%.该模型数值模拟计算结果能够满足一般工程领域的精度要求,可应用于三相水分共存的多层墙体热湿耦合传递过程数值模拟研究.

Mathematical model of coupled heat and moisture transfer for muhilayer wall with three-phase moisture was established using temperature and water vapor partial pressure as driving potential consider- ing moisture sublimation, desublimation, liquid/solid phase change and gas/liquid phase change. A 500 mm（length） × 450 mm（height）× 240 mm（thickness） test wall was built. Variations of temperature and equilibrium relative humidity inside the test wall were tested through constant temperature and humid- ity box from room temperature to --33.94 ℃. The liquid/solid phase change characteristic was investiga- ted, and the reliability of the mathematical model was verified. The results show that there exist the same trend and a good agreement between the numerical simulation results and test results of temperature and partial water vapor pressure inside the test wall. The maximum relative error about temperature and par- tial water vapor pressure are 1.68% and 27.92% respectively, the mean relative error about temperature and partial water vapor pressure are 0. 44% and 13.50% respectively. The model can satisfy the accuracy demand for building engineering and can be applied for simulation study on coupled heat and moisture transfer for multilayer wall with three-phase moisture.