纳米铝粉/石蜡/膨胀石墨复合相变材料的制备及性能研究

Preparation and Study on the Performance of the Nano-Aluminum/Paraffin/Expanded Graphite Phase Change Composites

将具有导热系数高,与石蜡相容性较好特点的纳米铝粉加入到液体石蜡中,形成纳米铝粉/石蜡流体,利用膨胀石墨特有的网络状孔隙结构以及对石蜡的高吸附性能,制备出了纳米铝粉/石蜡/膨胀石墨复合相变材料,解决了纳米铝粉在液体石蜡中容易发生团聚和沉降的问题,并通过实验研究了其热物性能。研究结果表明:当石蜡与膨胀石墨质量百分比例为93/7,加入纳米铝粉的质量分数低于3%时,膨胀石墨可以稳定的吸附纳米流体,经反复循环蓄、放热,纳米流体不会出现泄漏问题,且对复合相变材料的体积和蓄热能力没有影响;膨胀石墨的网络状孔隙结构可以抑制纳米铝粉的团聚现象,但随着纳米铝粉含量的增加,纳米颗粒仍会发生团聚现象,复合相变材料的导热系数,蓄、放热速度均呈非线性增加。应控制纳米铝粉的加入量,当纳米铝粉质量分数为2%时,纳米铝粉颗粒未发生明显团聚现象,复合相变材料的热性能较好。

The nano-aluminum/paraffin/expanded graphite phase change composites which use expanded graphite to absorb the nano-aluminum/paraffin nano-fluid were prepared,and the problem of nanoparticle agglomeration and precipitation in liquid paraffin was solved. The thermal properties of the phase change composites were characterized by Laboratory measurements. The results showed that when the expanded graphite mass fraction is 7%,nano-fluid can be combined with expanded graphite steadily,and the nano-fluid does not leak out from the expanded graphite after many charging and discharging life cycles. Adding no more than 3% mass fraction of nano-aluminum does not affect the volume and the heat storage capacity of phase change composites. Expanded graphite can reduce the agglomeration of nanoparticles,but nanoparticles agglomeration phenomenon becomes significantly with the increase in thenano-aluminum content. The growth of thermal conductivity and heat transfer rate of the phase change composite is nonlinear. The amount of nano-aluminum should be controlled,and when the mass fraction is 2%,the agglomerationof nano-aluminum is negligible; the thermal performance of the composite phase change materials is quite well