Experimental study on heat transfer during melting in metal and carbon foam saturated with phase-change materials for temperature control in electronic devices

Abstract

Porous media embedded in phase-change materials (PCMs) have been widely applied to thermal management of electronic devices, whereas the influence mechanisms of the suppression of the natural convection of liquid PCM by the porous skeleton and anisotropy of the skeleton on the temperature response of the heat source are still unclear. In this study, an isotropic metal foam and several anisotropic carbon foams are embedded in paraffin and higher alcohol, respectively. The influences of copper-foam skeleton on the PCM natural convection, the evolution of PCM melting front, and the variation of heat-source temperature are studied. The effects of carbon-foam skeleton on the directionality of phase-change heat transfer and the variation of heat-source temperature are investigated. The embedding of metal foam can reduce the heat-source temperature, postpone the onset of PCM melting and the appearance of natural convection, and shorten the PCM melting duration mildly. The anisotropy of carbon foams causes the out-of-plane thermal conductivities of carbon-foam/PCM composites to be larger than the in-plane thermal conductivities. The composite with a low porosity possesses a low melting temperature and short duration of PCM melting process. The increase in ambient temperature causes the time required to trigger the melting of the carbon-foam/PCM composite to decrease but does not affect the melting duration. Conversely, an increase in heat flux reduces the melting duration.