蒸压加气混凝土砌块墙体热湿耦合传递特性

Coupled Heat & Moisture Transmission Characteristics of Autoclaved Aerated Concrete Block Wall

运用开尔文定律和克劳修斯-克拉贝龙方程,将多孔建筑材料内水蒸气传递量和液态水传递量转变为以水蒸气分压力为驱动势的统一函数,以温度和水蒸气分压力为驱动势建立了热湿耦合传递模型,并模拟分析了上海地区自然干燥状态下加气混凝土砌块墙体10a的热湿性能变化规律.结果表明：对于初始温度为298K,含湿量（质量分数,下同）分别为2.91%,3.45%,5.03%,8.60%的4种工况,经过1a的使用后,墙体内的温湿度分布不再受初始条件影响;在正常情况阶段,墙体内表面相对湿度均小于1.0,不会出现结露现象,但是在部分时段超过了0.8,易产生霉变;墙体内部含湿量呈周期性变化,空调季为3.34%~8.31%,平均值4.45%;采暖季为3.31%~3.69%,平均值3.47%.

Using Kelvin＇s equation and the Clausius-Clapeyron equation, vapor and liquid flows through porous building materials may be expressed as a unified functions using water vapor partial pressure as driving poten- tials. Mathematical model of coupled heat and moisture transfer for multilayer wall was established and valida- ted using temperature and water vapor partial pressure as driving potential. The temperature and moisture var- iations in 10 years aerated concrete masonry wall were simulated according to the typical meteorological data of Shanghai. With original condition that the temperature was 298 K, the mass moisture contents were 2.91 %, 3.45 %, 5.03%, 8.60% for four different construction conditions respectively, temperature and moisture distribution in wall was independent of original condition after one year of use. In phase of the normal use con- dition, the relative humidity inside wall was less than 1.0 without condensation occurring, but in some time period the relative humidity was higher than 0.8 causing mildew generation. Moisture content inside wall changed periodically, varying between 3.34 %-8.31% with an average of 4.45 % in air-conditioning season, 3.31%- 3.69 % with an average of 3.47 % in heating season.