Numerical investigation of the melting process of gallium under inclination and partial heating. (March 2023)

• Record Type: Journal Article
• Authors: Rivero, Michel; Orozco, Sayra; Beltrán, Alberto
• Is Part Of: Journal of energy storage. Volume 59(2023)
• Publication Date: 2023-03
• Subjects: PCM -- Gallium -- Melting process -- CFD -- Thermal energy management; Energy storage -- Periodicals; Energy storage -- Research -- Periodicals; 621.3126
• DOI: 10.1016/j.est.2022.106510
• Languages: English
• ISSNs: 2352-152X

Abstract

Abstract: Systems based on PCM rely not only on the capacity of the system to absorb or release energy but also on the rate at which these processes are carried out. The design and optimization of thermal management systems require understanding the phase change process under different conditions. In this work, the time-dependent phase change process is studied numerically. Gallium, contained in a thin cell, is considered the working fluid. Numerical modeling is done by ANSYS Fluent in two dimensions. This model is validated against reported experimental results. Subsequently, two conditions are systematically investigated: (i) inclination, considering five angles ( − 45, − 22 . 5, 0, 22 . 5, and 45° ), and (ii) partial heating, considering four relative heater sizes ( 0 . 25, 0 . 50, 0 . 75 and 1.00). Both cases are studied for three aspect ratios ( A = 0 . 50, 0 . 75, and 1.00). Results show that small aspect ratios and positive tilting angles could modify flow dynamics, which ultimately affects the melting process and the Nusselt number. Moreover, partial heating reduces up to 38% the melting time compared to the case in which the heat flux is distributed homogeneously along the entire length of the wall. These results could be used as guidelines to address the "rate problem" for practical applications. Highlights: Nusselt number, liquid fraction, and melting front are validated for a 2D model. Five tilt angles and four heater sizes are investigated for three aspect ratios. Flow dynamics and melting process are significantly modified under certain tilting. Partial heating has significant effects on the melting process. Smaller heater sizes lead to faster melting.