高海拔寒冷地区采暖散热器散热性能研究

发布时间：2019-06-09 20:00

【摘要】：我国现阶段对于高海拔寒冷地区的采暖设备缺乏明确的技术规程，也几乎没有生产厂家从事适合此地区的专用设备的生产，对于极端气候条件对设备性能影响的研究亦是少之又少。在进行高海拔地区采暖散热器的选择时，许多设计师对散热器的选型修正系数依靠经验选取，没有明确的修正方法，这无疑是不科学的。此种方法会导致室内环境的舒适度不满足要求，更会导致能源的浪费，因此开发一套适用于工程实践的设备选型修正方法具有很强的现实意义。 本文依托经典的传热学模型，采用理论研究与数值模拟及实验研究相结合的方法，对高海拔地区常用的三种类型的散热器的散热性能进行了分析，得出一套适合于高海拔地区的采暖散热器选型修正方法。 首先，笔者在前人研究的基础之上，总结了密度、运动粘度系数、导温系数等空气的热物性参数随海拔高度的变化规律。 其次，笔者采用解析解法建立了光面散热器和电散热器的数学传热模型。由于带肋散热器的几何边界条件十分复杂，笔者采用基于有限差分法的数值计算方法，将带肋散热器的传热模型离散化，分别针对边界节点和内部节点建立与之对应的离散方程。三种散热器的模型建立过程中均对热边界条件做了相应的简化。同时，由于方程中涉及到的参数较多，在模型的求解过程中采用试算法进行求解。 再次，笔者采用基于有限元法的COMSOL Multiphysics数值仿真模拟软件建立三种散热器的数值仿真模型，与此同时，对位于拉萨市的壁挂炉+散热器采暖系统进行了现场试验测试。本文将数值计算结果和实测数据与理论计算结果进行对比，得出数值计算结果和实测数据与理论计算结果的相对误差均小于20%，，从而验证了理论模型的正确性。 最后，笔者对影响散热器传热的关键因素进行分析，得出光面散热器和带肋散热器的传热系数随海拔高度的升高而降低，海拔高度每升高500米，传热系数衰减1.5%~2.5%；柱形电散热器的单位面积散热量限值随海拔高度的升高而降低，海拔高度每升高500米，其值衰减1%~1.5%。此外，笔者将大量的计算结果进行拟合，将光面散热器和带肋散热器的散热量修正系数拟合为相应的多项式。
[Abstract]:At this stage, there is a lack of clear technical regulations for heating equipment in high altitude and cold areas, and few manufacturers are engaged in the production of special equipment suitable for this area. There are few studies on the influence of extreme climate conditions on equipment performance. In the selection of heating radiator in high altitude area, many designers rely on experience to select the correction coefficient of radiator selection, and there is no clear correction method, which is undoubtedly unscientific. This method will lead to the comfort of indoor environment does not meet the requirements, but also will lead to the waste of energy, so it is of great practical significance to develop a set of equipment selection and correction methods suitable for engineering practice. Based on the classical heat transfer model and the combination of theoretical research, numerical simulation and experimental research, the heat dissipation performance of three types of radiators commonly used in high altitude areas is analyzed in this paper. A set of heating radiator selection and correction method suitable for high altitude area is obtained. First of all, on the basis of previous studies, the author summarizes the variation of thermal physical parameters of air with altitude, such as density, kinematic viscosity coefficient, temperature conductivity coefficient and so on. Secondly, the mathematical heat transfer models of smooth radiator and electric radiator are established by analytical method. Because the geometric boundary conditions of ribbed radiator are very complex, the heat transfer model of ribbed radiator is discretized by using the numerical calculation method based on finite difference method. The corresponding discrete equations are established for boundary nodes and internal nodes, respectively. The thermal boundary conditions are simplified in the process of modeling the three radiators. At the same time, because there are many parameters involved in the equation, the trial algorithm is used to solve the model. Thirdly, the numerical simulation model of three kinds of radiators is established by using COMSOL Multiphysics numerical simulation software based on finite element method. At the same time, the heating system of wall hanging furnace radiator located in Lhasa is tested in the field. In this paper, the numerical calculation results and the measured data are compared with the theoretical calculation results, and the relative error between the numerical calculation results and the measured data and the theoretical calculation results is less than 20%, which verifies the correctness of the theoretical model. Finally, the key factors affecting the heat transfer of radiator are analyzed, and it is concluded that the heat transfer coefficient of smooth radiator and ribbed radiator decreases with the increase of altitude, and the heat transfer coefficient of smooth radiator and ribbed radiator decreases with the increase of altitude, and the heat transfer coefficient decreases with the increase of altitude. The attenuation of heat transfer coefficient is 1.5% 鈮

本文编号：2495858