Influence of rotation on heat absorption performance of solid–liquid phase change tank

Abstract

The abundant and environment friendly solar energy is considered as the promising way to instead of traditional fusil energy for reducing carbon emission. Phase change tank (PCT) has been widely implemented in photo-thermal utilization of solar energy system, since PCT solves the imbalance of solar energy in time and space. Rotation application is arisen as an innovative way to improving heat absorption performance of the PCT. In this work, the effects of rotation velocity on the melting performance, heat transfer, and heat absorption characteristics in the PCT were investigated. Particular attentions were paid to the coupled influence of active (rotation) and passive enhancement (addition of metallic fins) upon the melting process. The Boussinesq approximation and an enthalpy-porosity model were applied for simulation. It was followed by assessing the performance of 10 rotation angular velocities from 0 to 2 rad·s−1. Results manifested that the best enhancement on melting performance was not achieved by the fastest rotation. The shortest melting time was achieved with the reduction of 55.02% at a rotational speed of 1.1 rad·s−1. The enhanced natural convection due to the optimized rotation resulted in a 47.79% increase in the Grashof number in comparison to stationary. Additionally, rotation was found to be effective in preventing local thermal overcrowding, which can impede heat transfer.