架空地板型燃池供暖农宅热传输模型研究

Traditional heating systems such as kang, heating wall and burning cave have been used in rural houses for residential heating in Northern rural China. The phenomenon of larger temperature difference in the whole rural house, higher indoor concentration of pollutants, lower thermal efficiency of heating systems are very common. Through a field of experiments, it’s significant to use radiant elevated floor heating based on the thermal utilization of a burning cave for the whole house heating could optimize the structure of the elevated floor, improve exergy efficiency of a burning cave, and predict the indoor air temperature in this object. The main research contents of this study are as follows: (1) Taking experimental data of the temperature variations as the objective basis for establishing and validating the mathematical model for describing the couple heat transfer process inside the elevated floor, while using a burning cave as the heating source ; (2) Study on the law of nonlinear cycle heat transfer of inner air flow inside the elevated floor, in order to analysis the impacts of the heat source position and structure characteristic of the floor on heat transfer process; (3) Taking the mathematical model for enhancing heat transfer process integrated with the mathematical model of (1), and the specific design parameters and The best threshold values could be discussed. Finally, the purpose of heat balance in energy-saving house, while using one burning cave as a single heat source could be taken out.

在我国北方农村地区，冬季通常采用灶炕、燃池、火墙等传统方式供暖，致使整栋农宅室内空间温差过大、室内污染物浓度严重超标、供暖系统热效率低下。通过实验研究表明，本项目设计建造的架空地板型燃池辐射供暖农宅能够有效解决上述问题。因此, 对其传热规律进行理论建模对于优化架空地板结构形式、提高燃池热效率以及预测农宅动态热响应特性具有重要意义。本研究的主要内容包括：(1)以架空地板内部温度场的实验数据为客观条件,建立燃池热源持续供暖特征条件下,架空地板内部辐射对流耦合传热数学模型；(2)分别用温升速率及热量分布均衡度描述整栋农宅地板下空腔内部传热规律，分析热源位置及架空地板结构特性对热量传递过程的影响；(3)将(1) (2)中建立的数学模型与农宅传热模型进行集成，探讨热源强度及农宅耗热量对热量输配过程的影响规律。最终实现以燃池为单一热源持续向整栋节能农宅均衡供暖的目的。

首先，根据前期实验数据及理论解析，给出架空地板型燃池辐射供暖农宅整体及分区传热过程的宏观物理模型，并给出燃池供暖系统的供暖特征及传热影响因素综合解析表达式，作为所建立模型的热源边界条件；其次，建立架空地板内部平板间辐射、空气自然对流、金属薄板辐射、导热的复合传热模型，通过数值计算，分别得到提升地板架空层内部空气温降速率及热量分布均衡度的优化方法，得到架空地板内部强化传热机理及其综合影响因素；再次，将架空地板内部复合传热模型与供暖农宅室内空间传热模型进行集成，进而将模型简化得到架空地板型燃池辐射供暖农宅室内空气温度动态变化的预测计算模型；最终，确定基于燃池热利用的架空地板辐射供暖系统的强化传热方式及结构特性设计参数的最佳阈值范围，并优化燃池与农宅之间的相对位置关系，改进建筑空间布局及传热路径，使燃池热能达到最大化利用及均衡传输分配。