棕榈酸/膨胀石墨复合相变材料的制备及性能研究

Preparation and Thermal Performance of Palmitic Acid/Expanded Graphite Composite Phase Change Materials

棕榈酸是有机固液相变材料,本文通过添加膨胀石墨对其性能进行改善并采用扫描电镜(SEM)、差示扫描量热仪(DSC)、充/放热性能测试对制备出的膨胀石墨质量分数分别为1%,3%,5%,8%的棕榈酸/膨胀石墨复合相变储能材料的结构及热性能进行表征。结果表明,棕榈酸/膨胀石墨复合相变材料保持了膨胀石墨原来疏松多孔的蠕虫状结构,其相变温度与棕榈酸相似,相变潜热与对应质量含量下的棕榈酸相当;随着膨胀石墨添加量的增多,受到黏度和自然对流双重作用的影响,复合相变材料的蓄放热速率先减小后增大,因此适量的膨胀石墨可改善棕榈酸的传热性能。

Palmitic acid（PA） is a kind of organic solid-liquid phase change material.In this paper,the thermal performance of palmitic acid was improved through adding expanded graphite（EG） into it.The structure and phase change properties of prepared palmitic acid/expanded graphite composite phase change materials（PCMs） for thermal storage with EG mass fraction of 1%,3%,5%,8%were characterized via scanning electronic microscope（SEM）,differential scanning calorimeter（DSC）,and thermal performance tests in a latent heat storage（LHS） system.The results indicate that the PA/EG composite PCMs remain porous and vermiform structure just as that of EG,the phase transition temperature of the composites is close to that of PA and the latent heat is equivalent to the calculated value based on the mass fraction of PA in the composites.Considering the influence of viscosity and natural convection during the phase transformation processes of the composite PCMs,the heat storage and release rate of the composites decreases firstly and then increases rapidly with expansion of EG addictive.