Volume 3: Innovative Solutions for Energy Transitions: Part II

How Mushy Zone Affect the Thermal Performance of Low-melting Alloy Bin Ding, Ze-kai Gu, Yong Guo, Liang Gong

Abstract

The low-melting alloys composed of Sn, Bi, Pb, Cd, In, Ga and Sb show good application prospect in phase change heat sink and heat storage system. Thereby, a well understanding of the melting behaviors of low melting-alloys is crucial to design efficient thermal heat storage appliances or heat sinks. In this paper, a one-dimensional enthalpy-based model is established to explore the melting process of an alloy bar. As the results, the effect of mushy zone temperature range which can be reflected by phase change temperature interval and average phase change temperature is discussed on the motion of mushy zone. The results indicates that the increase of surface temperature is significantly delayed by the release of latent heat. Moreover, the duration of mushy zone gradually increases along the vertical direction, which attributes to the increase of thermal resistance. Reducing the average temperature of mushy zone instead of increasing the temperature interval is an effective way to improve the thermal performance of alloy. Specifically, the effective protection time increases 22% with the average temperature decreases from 70 to 50 oC. The calculated results provide theoretical guidance for selecting the working medium of the thermal heat storage appliances or heat sinks.

Keywords Low-melting alloy, Mushy zone, Melting behavior, Thermal performance