Effect of partially filled copper foam on the thermal performance of phase change materials under different direction external forces

Abstract

Temperature control of aerospace on-board electronics can be realized by using foam metal to enhance heat transfer of phase change material (PCM). In this paper, it is proposed to optimize the thermal performance of composite PCM (CPCM) by partially filling copper foam, and the effect of filling ratios ((3 = 0.25, 0.50, 0.75 and 1.00) under different external forces is experimental studied. First, comparative studies on the evolution of phase interface and average heat transfer coefficient show that full filled foam metal weakens the natural convection of PCM especially under negative force. Then, the melting results of partially filled CPCM under different forces indicate that the heat transfer increases with the increase of filling ratio, but the enhancement rates are different under different force fields. Under normal gravity, the melting time can be reduced by 12 %, 27 %, 41 % and 45 % with (3 = 0.25, 0.50, 0.75 and 1.00 respectively. And the melting time of (3 = 0.75 CPCM and full filling CPCM is almost the same under negative force. Under the same filling ratio, the enhanced convection by negative force results in the lowest heat wall temperature. Moreover, the negative force is beneficial for the proportion of latent heat thermal energy storage (LHTES) of CPCM, and the percentage of LHTES reaches 81 % when the best filling ratio is 0.5. In conclusion, this study provides a foundation for optimizing latent heat thermal management in airborne electronic equipment.