北方农村烟道型复合墙体热工基础理论及实验研究

This project puts forward a new type of flue composite wall, which can both recycle exhaust waste heat of Kang and improve thermal performance of building envelope and indoor thermal and humid environment, aiming at blocking the deadlock high energy consumption and poor indoor environment in rural residential buildings of northern area. By analyzing the flow mechanism of gas flue and the main controlling factors of heat and moisture transfer under the effect of multi-field coupled potential difference and based on air distribution theory in finite space and field synergy theory, basic theory research and dynamic experiment are processed to solve the problem of coupled heat and mass transfer in forced flow of confined space, which consists of heat conducting boundary condition problem and multi-point radiation coupling thermal-mass heat transfer problem. And the thermal insulation and moisture proof measures of multi-layer composite wall containing gas are also investigated. According to theoretical studies, the field synergy law of the fluid flow and the coupled transfer, the thermodynamic characteristics of the enclosed thermal-insulating cavity are determined. .The innovative concept of flue composite wall for northern rural area not only supplements the coupled transfer theory with dynamic heat-conducting boundary conditions, but also reveals coupled migration law of composite wall with cavities. This low-cost active building energy conservation technology provides theoretic reference and technical supports for energy conservation of building envelopes and for indoor environment improvement in northern rural area, thus gaining a broad prospect in application due to its considerable social and economic benefit.

本课题针对北方农村建筑围护结构能耗高，室内环境差等共性问题，结合农宅建筑结构，提出一种既能回收农村灶炕排烟余热，又能改善建筑墙体热工性能和室内热湿环境的烟道型夹层复合墙体，通过分析多场耦合势差作用下，有限空间内烟气流态机理及影响热湿输运的主控因素，基于有限空间气流分布理论和场协同理论，对带有导热的有限空间内气体受迫流动与多点辐射耦合的热质换热问题，以及含有气体夹层的多层复合墙体保温隔湿问题，进行了热工基础理论与动态实验研究，明确了流体流动与热质耦合传递的场协同规律，以及封闭空腔保温隔湿的热力学特征。适宜于北方农宅的烟道型夹层复合墙体的提出，不仅创新和完善了带有导热动态边界条件的热质耦合输运理论，而且揭示了带有空腔的复合墙体热湿运移规律，研究成果形成的低成本主动式建筑节能技术，可为北方农村建筑围护结构的节能建设和室内环境改善，提供理论依据和技术支持，具有极大社会经济效益和广泛推广应用前景。

本课题提出一种适宜北方农村建筑的新型烟道型复合墙体。以热烟气在复合墙体内流动换热以实现余热回收与节能隔湿的目的。采用实验与模拟相结合的方法，测试了复合烟道墙体的热工性能，并通过模拟确定了最佳的几何结构。针对流通烟道夹层的换热问题，建立了紊流自然对流和辐射耦合传热模型；针对封闭夹层内的流动换热问题，建立层流自然对流与辐射耦合传热模型；针对封闭夹层内的辐射问题，建立附加源项辐射耦合计算模型。通过对烟道型复合墙体的理论与实验研究，完善了农宅新型维护结构的耦合流动换热规律，同时揭示了复合墙体的热湿传递规律，为今后农宅的节能研究提供了理论基础。.本课题的研究结果对农宅建筑节能提出了一种新的思路，通过回收烟气余热，提高农宅采暖系统热效率。带有空腔的复合墙体可以减少通过墙体热损失，同时可以降低湿度传递，降低墙体结露与发霉的风险。研究成果具有极大的应用前景及社会经济效益。