湿热气候建筑墙体热湿耦合传递共轭模型与实验研究

There are coupled heat and moisture transfer and moisture accumulation in porous building envelope subjected to the hot humid climate, resulting in a serious impact on thermal performance of building and its energy consumption and indoor environment. Most of existing studies adopted simplified methods (e.g. the first boundary condition, the second boundary condition and the third boundary condition) to reflect the effect of air boundary conditions on building envelope. However, surrounding air conditions are the critical reasons for the coupled heat and moisture transfer and moisture accumulation in building envelope when don’t take into consideration the initial temperature and humidity and heat and humidity source/sink. Based on the theory of heat and mass transfer through porous media and aerodynamic theory, coupled heat and moisture transfer in building envelope and surrounding air will be studied, after which the hydrothermal models in building envelope (HM model) and surrounding air (CFD model) will be built respectively. And hydrothermal performance of the interface between building envelope and surrounding air will be studied, and then a conjugate model will be established. The conjugate model will be solved by programming, and an effective experimental validation and test technology will be developed to validate the conjugate model. The effect of coupled heat and moisture transfer on the hydrothermal performance of building will be analyzed by the conjugate model in the hot humid climate. This research will provide a theoretical basis and technical guidance for optimizing building thermal performance, energy consumption and improving the indoor environment.

湿热气候作用于多孔介质建筑墙体，导致墙体中热湿耦合传递和湿积累，严重影响建筑热工性能、能耗及室内环境。建筑墙体热湿耦合传递的已有研究大多采用简化方法（例如，第一、二、三类边界条件）处理空气边界对墙体的作用，而不考虑墙体内部初始温湿度及内部热湿源/汇时，周围空气状况是引起墙体热湿耦合传递和湿积累问题的根本原因。本项目基于多孔介质热质传递与空气动力学理论，研究多孔介质墙体热湿耦合传递和周围空气热湿特性，分别建立墙体与空气热湿模型（HM和CFD模型），然后基于墙体-空气交界面的热湿特性，构建墙体-空气热湿耦合传递共轭模型。编程求解共轭模型，开发有效的实验测试技术验证共轭模型。用共轭模型研究湿热气候地区墙体热湿耦合传递对建筑热湿性能的影响，为优化建筑热工性能、优化能耗预测及改善室内环境提供理论支持和技术指导。

如何建立充分反映墙体热湿迁移机理的并能快捷有效地求解的墙体热湿传递瞬态数学模型，进而准确预测多孔介质墙体内部热湿传递与湿积累情况，分析墙体热湿耦合迁移与湿积累对建筑墙体微生物污染、建筑能耗预测的作用，是建筑与环境相关领域亟待解决的问题。本项目基于多孔介质热质传递和空气动力学理论，研究多孔介质墙体热湿耦合传递和周围空气热湿特性，分别建立墙体与空气热湿模型（HM和CFD模型），然后基于墙体-空气交界面的热湿特性，构建墙体-空气热湿耦合传递共轭模型。提出了一种可以同时测量多孔介质墙体内局部温湿度的方法，在实际湿热气候下搭设建筑墙体热湿迁移足尺寸实验平台，并开展实验测试。通过对比数学模型数值解和实验测试结果、经典案例，验证了新建立的数学模型。分析数学模型物性参数的灵敏度，发现液态水传递系数Dl与导热系数λ对墙体的温湿度分布影响较大。建立了基于瞬态温湿度及其持续时间的墙体内霉菌滋生风险评价方法，以红砖墙体为对象进行研究，结果表明：太阳辐射对墙体内霉菌滋生风险影响较大，太阳辐射越弱墙体内霉菌滋生风险越大; 室内相对湿度波动对墙体外侧霉菌滋生风险影响很小，对内侧霉菌滋生风险影响很大；室内温度对墙体霉菌滋生风险有显著影响，室内温度升高导致墙体内、外侧霉菌滋生风险分别呈现升高、降低趋势；南方绝大部分地区红砖墙体水泥砂浆与红砖夹层存在霉菌滋生风险，总体上呈现东部比西部高、南部比北部高的趋势。考虑墙体内湿传递情况下优化保温层厚度。墙体热湿迁移模型的建立、热湿迁移实验测试的开展以及对建筑墙体霉菌滋生风险、建筑墙体热湿性能以及建筑保温层厚度的分析等工作的开展，为优化建筑热工性能、优化能耗预测及改善室内环境提供理论支持和技术指导。