内置分离式热管墙体的传热特性研究

发布时间：2018-06-21 18:03

本文选题：分离式热管 + 墙体供暖系统　；参考：《南京工业大学》2015年硕士论文

【摘要】：将热管运用于建筑供暖的研究目前相对较少,还处于初级阶段。在充分利用可再生能源(太阳能)的前提下,以热管技术为基础,运用“被动式”设计理念,结合太阳能热水器,提出了一种太阳能—内置分离式热管墙体供暖系统。目前,墙体内安装热管的传热特性的研究并不多,较多的研究还是针对热管自身的传热特性。本文的主要工作为了确定热管供暖墙体的结构形式,分析墙体结构以及安装的结构形式对热管传热特性的影响,提出增强热管与墙体传热的技术措施。以地板辐射传热的研究作为本课题研究的基础,建立墙体供暖系统的数学模型。针对本课题的研究目的,对墙体采暖系统的传热过程作适当假设,建立墙体采暖系统的二维传热模型,假设系统处于连续运行工况,不考虑热源的间歇性(太阳能资源的不连续性),整个传热过程视为稳态过程。运用数值模拟软件计算内置分离式热管墙体的传热过程,针对热管数量、安装翅片长度、翅片厚度、结构层材料这四个因素对热管传热功率的影响,同时分析墙体整体以及表面的温度分布。本课题提出的太阳能——内置分离式墙体供暖系统具有可无动力工作的特性,实现供暖过程的“零能耗”。热管的数量对热管自身的热流密度影响较小。在填充及抹平层材料为水泥砂浆、无翅片的条件下,安装在墙体内的热管数量为4根时的热管表面热流密度为432.3W/m2；增加到12根时。热流密度为398.8W/m2,只降低了7.7%。安装翅片可以显著提升热管的传热效率。在填充及抹平层材料为水泥砂浆、热管数量为8根的条件下,安装翅片的长度分别为0L、1/4L、1/2L、3/4L、1L时,最大提升幅度可达211.4%。同时,结构层材料的选择对热管传热效率的影响很大。结构层分别使用灰砂砖、加气混凝土砌块时,墙体表面热流密度分别为615.3W/m2、276.3W/m2。使用灰砂砖的热管表面热流密度相比于使用混凝土砌块的提高了122.7%。使用加气混凝土砌块和灰砂砖,两者热管传热效率相差了一倍之多。在选择结构层材料时,应综合考虑各方面因素,选出适宜的材料。
[Abstract]:The application of heat pipe in building heating is relatively rare, and it is still in the primary stage. On the premise of making full use of renewable energy (solar energy), based on heat pipe technology, using the "passive" design concept and combining with solar water heater, a solar-built-in heat pipe wall heating system is proposed. At present, there are few researches on the heat transfer characteristics of heat pipe installed in the wall, but more researches are focused on the heat transfer characteristics of the heat pipe itself. The main work of this paper is to determine the structure of heat pipe heating wall, analyze the influence of wall structure and installed structure on heat transfer characteristics of heat pipe, and put forward technical measures to enhance heat transfer between heat pipe and wall. Based on the research of floor radiation heat transfer, the mathematical model of wall heating system is established. For the purpose of this research, the heat transfer process of the wall heating system is properly assumed, and the two-dimensional heat transfer model of the wall heating system is established, assuming that the system is in continuous operation condition. The whole heat transfer process is considered as a steady state process regardless of the intermittency of the heat source (discontinuity of solar energy resources). The heat transfer process of heat pipe wall is calculated by numerical simulation software. The heat transfer power of heat pipe is affected by four factors, such as the number of heat pipe, the length of fin, the thickness of fin and the material of structure layer. At the same time, the temperature distribution of the whole wall and the surface is analyzed. The solar-built-in wall heating system has the characteristics of no power operation, and realizes the "zero energy consumption" in the heating process. The quantity of heat pipe has little effect on the heat flux of heat pipe itself. Under the condition of filling and leveling layer with cement mortar and no fins, the heat flux density of heat pipe surface when the number of heat pipe installed in the wall is 4 is 432.3 W / m ~ 2; when the heat pipe is increased to 12, the heat flux on the surface of the wall is 432.3 W / m ~ (2). The heat flux was 398.8 W / m ~ 2, only a decrease of 7.7%. The heat transfer efficiency of heat pipe can be greatly improved by installing fins. Under the condition that the filling and leveling layer material is cement mortar and the number of heat pipes is 8, the maximum lift can reach 211.4 when the length of the finned fin is 0 L / 1 / 4 L / 2 L / 2 L / 3 / 4 L / 1 L respectively. At the same time, the selection of structural layer material has great influence on heat transfer efficiency of heat pipe. The heat flux on the wall surface is 615.3W / m2276.3W / m2 when the structure layer is made of lime sand brick and aerated concrete block respectively. The heat flux on the surface of heat pipe with gray sand brick is 122.7 higher than that with concrete block. Using aerated concrete block and lime sand brick, the heat transfer efficiency of heat pipe is twice the same. In the selection of structural layer materials, all factors should be considered synthetically and the suitable materials should be selected.
【学位授予单位】：南京工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU111.4;TU832

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