Close-contact melting regulated by structured slip surfaces

Abstract

This paper investigates the close-contact melting (CCM) of phase change materials on effective slip surfaces enabled by superhydrophobic microgroove structures. The CCM of ice cubes on hydrophobic grooved surfaces with different parameters is measured, and a modified theoretical framework is developed to account for the spatial variation of the liquid–gas meniscus induced by the pressure gradient along the flow direction. The modified model predicts lower melting rates, attributed to the smaller equivalent average meniscus curvature (i.e., a flatter meniscus), which reduces the slip length and slows the drainage of the melt film. The experimental results validate that the heat transfer of CCM can be further enhanced under specific groove geometry conditions for the first time and confirm the predictions of the modified model. A detailed test of varying superheat conditions was conducted to verify the applicability of the model. These findings provide experimental support and application potential for using slippery surfaces to enhance CCM under specific conditions, which is of great significance for scientific exploration and engineering applications, including thermal management and thermal energy storage.