石蜡/膨胀石墨/石墨片复合相变材料导热性能研究

Study on Heat Conductivity of Paraffin/Expanded Graphite/GraphiteSheet Composite Material

相变材料的导热性能对蓄热能力和能量转化速率具有重要影响。本文以58号全精炼石蜡为基底相变材料,利用真空吸附法将石蜡与膨胀石墨结合,再通过搅拌将石墨片与材料均匀混合,以模压法制备了定形复合相变材料,并通过实验测试了复合相变材料不同方向导热系数。实验结果表明:制备的复合相变材料导热性能具有明显的各向异性,垂直于压缩方向的导热性能远高于压缩方向的导热性能;同时也发现石墨片的添加可以有效的增强复合相变材料的导热性能,复合相变材料压缩方向导热性能随石墨片的添加先增大后减少;垂直于压缩方向的导热性能随石墨片的添加线性增强。

The thermal conductivity of phase change materials plays a key role in the thermal storage capacity and energy conversion efficiency.In this study,No.58 refined paraffin used as base phase change material is combined with expanded graphite by vacuum adsorption,then mixed with the graphite sheet uniformly by stirring.The composite phase change material is shaped by molding method,and the thermal conductivities in different directions are measured.The results show obvious anisotropic thermal conductivities,and the thermal conductivity in compression direction is much higher than that perpendicular to the compression direction.It was also found that the addition of graphite sheet could effectively enhance the thermal conductivity of the composite phase change material.The thermal conductivity in the compression direction increases at the first stage and decreases with the addition of graphite sheet at the second stage,while the thermal conductivity perpendicular to the compression direction increases linearly with the addition of graphite sheet.