Empirical correlations to quantify the effect of metal foam on solidification process in constant thermal capacity and constant volume systems

Abstract

Abstract Metal foams have been extensively studied to enhance the performance of the Phase Change Materials (PCMs) based Latent Heat Thermal Energy Storage (LHTES) systems. The studies in the literature are primarily focused on analyzing the effect of specific metal foam on the heat transfer augmentation and lacks comprehensive analysis. The present study aims to understand the interdependent effect of thermophysical properties of PCM and metal foam, system geometry, and operating condition on the potential of metal foams to enhance phase-change processes. Besides, the studies are limited to analyze the effect of metal foam addition on phase change processes inside predefined geometries, which fails to consider the reduction in the thermal capacity as the void volume available for the PCM decreases upon the addition of low porosity metal foam. It is crucial to maintain the constant thermal capacity of the LHTES system from both an application and a fundamental analysis perspective. Therefore, in the present study, the dimensions of the LHTES systems are altered to maintain the thermal capacity of the systems, which changes when metal foams are added. Empirical correlations are developed to estimate the effect of embedding metal foam in PCM on the solidification process of PCM in both constant volume and constant thermal capacity systems. These correlations are validated using numerical results, and the differences are limited to within 1% and 1.6% for the solidification time and average heat flux, respectively. The correlations can be extended to unidirectional melting processes with minor modifications, and it reduces reliance on experimental and numerical analysis.