碳纳米管/石蜡复合相变材料的蓄放热特性研究

Experimental study on the heat storage and release characteristics of carbon nanotube/paraffin composite phase change materials

碳纳米管可在石蜡中形成有效的传热网格,增加复合材料传热路径,提高传热系数。使用直径为8~12nm的工业级碳纳米管粉末,将含量为1%、3%、5%、7%的碳纳米管分别加入石蜡中,并对其进行蓄放热性能测试。结果表明:碳纳米管含量为7%时,复合相变材料在水平方向的蓄热性能最好,上下截面达到相变时间分别是纯石蜡的61.1%和41.7%,且垂直方向上复合材料温度均匀性也很好;含量为5%时蓄热性能略差;含量为1%和3%时蓄热性能改善不明显。在放热过程中,含量为7%的复合相变材料放热效果最好,达到相变温度时间比纯石蜡缩减了78.3%。

Carbon nanotube can form an effective heat transfer grid in paraffin wax,increase the heat transfer path of composites and improve the heat transfer coefficient.Industrial carbon nanotube powder with a diameter of 8~12nm was used.Four kinds of carbon nanotube contents of 1wt%,3wt%,5wt%and 7wt%were added to paraffin,respectively,and their heat storage and release properties were tested.The experimental results showed that when the mass fraction of carbon nanotube was 7wt%,the heat storage performance of the composite phase change material was the best in the horizontal plane,and the times for the upper and lower sections to reach the phase transition were 61.1%and 41.7%of that of pure paraffin,respectively.The temperature uniformity of the composite material in the height direction was the best.When the mass fraction of carbon nanotube was 5wt%,the heat storage performance was slightly poor,and when the mass fraction was 1wt%and 3wt%,the heat storage performance was not significantly improved.In the exothermic process,the composite phase change material with 7wt%mass fraction had the best exothermic effect,and the time to reach the phase change temperature was reduced by 78.3%compared with pure paraffin.