热湿气候地区多层墙体热、空气、湿耦合迁移动态模型及实验研究

In hot and humid climate of China, the moisture-related problem including engineering durability and mold contamination which is caused by heat, air and moisture transfer is more and more serious. Based on the theory of heat and mass transfer through porous media, energy and mass conservation, a dynamic heat, air and moisture transfer mathematical model will be established using non-equilibrium thermodynamic equations. The effect of wind-driven rain, air infiltration, moisture evaporation/condensation within the wall and solar radiation etc on the heat and moisture transfer will be considered in the model. In order to improve the model accuracy and numerical stability, a two-way expansion、time domain recursive method and dynamic boundary conditions will be used to solve the governing equations. An effective experimental validation and test technology will be developed. The effect of heat, air and moisture transfer through multilayer wall on the wall hygrothermal performance will be analyzed. The moisture damage condition of the wall will be predicted and the method of selecting an appropriate restoration material will be proposed. This research will provide a theoretical basis and technical guidance for the designing of energy-saving wall, reducing the chance of condensation within wall, preventing the mildew and mold growth.

我国湿热气候地区由于墙体热、空气、湿耦合传递所引起的工程耐久性、霉菌污染等湿问题日益严重。本项目在多孔介质热质传递理论、能量和质量守恒定律的基础上，利用非平衡热力学方程，考虑风夹雨、空气渗透、墙体内部水分蒸发冷凝及太阳辐射等影响因素，研究墙体内热、空气、湿耦合传递机理，建立多层墙体热、空气、湿耦合传递动态数学模型；采用two-way expansion、递归展开算法和动态边界条件等先进数值技术，提高模型准确性和数值稳定性；开发有效的实验验证测试技术。研究墙体热、空气、湿耦合传递诸因素对墙体热湿性能的影响；预测墙体的湿损坏情况，提出修复材料的选择方法，为我国湿热气候地区的节能建筑墙体的设计，降低墙体内部冷凝几率，防止墙体霉菌生长提供理论依据和技术指导。

我国湿热气候地区由于墙体热、空气、湿耦合传递所引起的工程耐久性、霉菌污染等湿问题日益严重。本项目在多孔介质热质传递理论、能量和质量守恒定律的基础上，利用非平衡热力学方程，考虑空气渗透、墙体内部水分蒸发冷凝及太阳辐射等影响因素，研究了墙体内热、空气、湿耦合传递机理，建立了多层墙体热、空气、湿耦合传递动态数学模型。在时域上采用了递归展开算法，在空间域上采用有限容积法对方程进行离散，研究结果表明递归展开算法时间步长的改变对计算结果影响较小，可通过增加时间步长方法来减少工作量，有效的克服了有限差分法对时间步长的限制问题。根据我国南方热湿气候地区的实际气象条件，对各物性参数进行了灵敏度分析，得出了影响模型精度的主要参数。研究了墙体热湿耦合传递诸因素对墙体热湿性能的影响。分析了我国热湿气候地区两种主要墙体的热湿迁移情况及几种墙体材料湿分对导热系数的影响。在典型热湿气候地区南昌搭建了足尺寸构件热湿耦合迁移试验台验证了模型的正确性。预测墙体的湿损坏情况，提出了修复材料的选择方法，为我国湿热气候地区的节能建筑墙体的设计，降低墙体内部冷凝几率，防止墙体霉菌生长提供理论依据和技术指导。本项目中模型及实验研究结果能推动我国多.孔介质墙体热湿迁移研究，对工程中热湿问题有着重要指导作用。