【摘要】 通过熔融共混方法配制了不同比例的石蜡/高密度聚乙烯/膨胀石墨复合定形相变材料，通过渗漏测试和热物性测试确定了材料最佳配比，并采用数值模拟方法研究夏季工况下加入该材料的相变墙体应用效果及相变蓄能单元的供冷特性。测试结果表明：复合定形相变材料的最佳配比为复合相变石蜡(52#固体石蜡与液体石蜡的质量比5∶5)与高密度聚乙烯的质量比为8∶2,再掺入质量分数3%的膨胀石墨；最佳配比相变材料的相变温度为26.2℃,导热系数为0.476 4 W/(m·K),质量损失率为1.86%,相变潜热为87.36 J/g。模拟结果显示：在建筑墙体中加入该复合定形相变材料能够有效减缓室内温度的波动，提高室内热舒适性；供冷工况下相变材料的适宜相变温度为26℃;较大的相变材料导热系数可以降低墙体内壁面温度并提高墙体的热流密度；增大相变材料的相变潜热可以降低墙体内壁面温度和热流密度波动。研究结果可为复合定形相变材料的制备及应用提供数据支撑。更多还原

【Abstract】 The paraffin/high-density polyethylene/expanded graphite composite shape-stabilized phase change materials with different ratios were prepared through melt blending method. The optimal material ratio was determined through leakage tests and thermophysical property tests. A numerical simulation method was employed to investigate the application performance of phase change walls incorporating this material under summer operating conditions, as well as the cooling characteristics of the phase change thermal energy storage unit. The test results indicate that the optimal composition of the composite shape-stabilized phase change material is composite phase change paraffin(52# solid paraffin to liquid paraffin ratio of 5∶5) and high-density polyethylene with a mass ratio of 8∶2, followed by the addition of 3% mass fraction of expanded graphite. The phase change temperature of the phase change material with the optimal proportion is 26.2 ℃, the thermal conductivity is 0.476 4 W/(m·K), the mass loss rate is 1.86%, and the latent heat of phase change is 87.36 J/g. The simulation results show that adding this composite shape-stabilized phase change material to the building wall can effectively mitigate the fluctuation of the indoor temperature and improve the indoor thermal comfort. The appropriate phase transition temperature of the phase change material under the cooling condition is 26 ℃. A relatively high thermal conductivity of the phase change material can reduce the temperature of the inner wall surface and increase the heat flux density of the wall. Increasing the latent heat of phase transition of the phase change material can reduce the temperature of the inner wall surface of the wall and the fluctuation of the heat flux density. The research results can provide data support for the preparation and application of the composite shape-stabilized phase change material.更多还原