肋片强化传热储能单元相变过程数值模拟

Numerical Simulation of Melting Process of Phase Change Materials with Fin Arrays

本文对阵列式肋片强化传热的石蜡类相变储能单元进行数值模拟,相变材料储存于阵列式肋片之间,热量通过铝材基座和肋片传递给相变材料。采用十八烷作为数值模拟的相变材料,其熔点是28℃,密度和动力粘度随温度变化,通过改变肋片尺寸以及边界条件研究相变材料的融化过程,通过分析温度场,流场,固-液两相分布探究相变规律,用无量纲参数分析肋片尺寸以及不同边界条件对相变过程的影响。结果表明,受自然对流的影响,随着时间推移,肋片处热流密度先增加后减少,基座处热流密度大幅度升高;相变材料融化后,对流换热是主要的传热方式;对于相变层偏薄的相变储能单元,宜采用小尺寸肋片,相变层偏厚的相变储能单元,宜采用大尺寸肋片。

Numerical simulation is carried out to study the phase change materials（ PCM） melting process with fin arrays to enhance heat transfer. Octadecane is selected as the PCM,which is filled in an aluminum box with fin arrays. Its melting point is 28℃,and density and dynamic viscosity vary with temperature. The temperature field,flow field,and solid-liquid phase distribution during the PCM melting process are numerical analyzed. The effects of fin size and boundary conditions are also studied by dimensional analysis method. The results show that with the passage of time,the heat flux at the fin increases firstly and then decreases,the heat flux at the base increases all the time. After the PCM melts,convective heat transfer is the main heat transfer method. When the phase change layer is thin,it is appropriate to use small fins; when the phase change layer is thick,it is appropriate to use large fins.