The thermocapillary effects in phase change materials in microgravity experiment: Design, preparation and execution of a parabolic flight experiment

Abstract

The Thermocapillary Effects in Phase Change Materials in Microgravity (TEPiM) experiment aims to analyse the potential of Marangoni convection for heat transfer enhancement in Phase Change Materials (PCMs) in weightlessness, where the slow characteristic time of the phase change process constrains their use as thermal control devices. On ground, natural convection masks the influence of Marangoni flow, which means that quantifying each contribution to the heat transfer rate of the system precisely is not possible. In this sense, the microgravity environment provided by parabolic flights gives an excellent opportunity to execute an experiment on PCMs phase change coupled with thermocapillary convection, and retrieve useful data to validate theoretical and numerical models. We note that such microgravity research has never been performed prior to this project. In this paper, we describe the design, preparation and performance of the TEPiM microgravity experiment, executed during the 65th ESA Parabolic Flight campaign. The experiment cells, filled with solid n-octadecane and a layer of air, were heated to observe the melting process under the microgravity portions provided during the flight. The promising results obtained support the positive impact of thermocapillary effects in PCMs melting, and suggest themselves for further investigation. We also expect that the valuable lessons learned presented here will help the scientific community in developing future microgravity experiments of this nature.