封装蓄能材料用于地板辐射采暖的数值模拟

对于封装相变材料的研究,通常借助于热容法和焓法。热容法直接以温度为待求变量,但必须跟踪液相的界面,而且一般用于相变温度为一点的理想相变材料。热焓法以温度和焓为待求变量,得到含有这两个变量的能量方程,再由相变材料的温度与焓之间的关系,求得温度分布。焓法不必跟踪相变界面,且能量方程适用于固相、液相及相变区,使问题大大简化,尤其适用于多维问题。本课题利用焓分析法,对一种封装相变蓄能材料用于低温热水地板辐射采暖系统进行了数值模拟。本文着重研究了蓄能地板在提供不同的热水温度、不同的供水流量、不同的热水管间距和不同的地板覆盖层条件下的蓄热时间规律。

Numerical Simulation of a Kind of Enclosed Phase Change Material Using by Radiant Floor Heating System

As to study enclosed phase change material,the methods of enthalpy and heat capacity are used to adopt.Heat capacity method is directly based on temperature,but it needs to track the solid-liquid interface.Furthermore,it is usually used in ideal phase change material(PCM) at a certain temperature.However,enthalpy is based on enthalpy and temperature.According to the relationship of the temperature and enthalpy in the energy equation,the temperature distribution will be obtained.The phase change of the shape-stabilized PCM often occurs in a wide temperature range rather than at a certain temperature.The advantage of the enthalpy is that the solid-liquid interface needn't be tracked and the energy equation is suitable for solid,solid-liquid and liquid,which remarkably simplifies the simulation,therefore it is especially suitable for the multi-dimensional models.Using the method of enthalpy,a kind of enclosed PCM used in radiant floor heating was numerical simulated.In this paper,the PCM thermal storage time was mainly studied under different supply water temperatures,different supply water flows,different distances between heat coils,different floor covers.