纳米填料对储能式散热器性能影响的数值研究

针对储能式电子器件散热器性能受相变材料较低导热能力限制的问题,采用添加高导热纳米填料的方法提高相变材料的表观导热系数,并对储能式散热器的性能提升潜力进行分析. 在短时大功率加热(热流密度为10 W/cm2)的条件下,对以二十烷为相变材料的储能式散热器在添加碳纳米管填料之后的工作过程(熔化和凝固传热)进行了三维数值模拟. 结果显示,由于相变材料表观导热系数的提高,散热器的性能随碳纳米管添加量的增加而提升,其提升程度与添加量呈近似线性相关| 当加入体积分数为10%的碳纳米管时,散热表面的最大温升相对于无碳纳米管的情形降低了8 ℃,散热器的等效总热阻则降低了14%,说明该方法是提高储能式散热器性能的有效途径．

Numerical investigation of influence of nanofillers on performance of energy storage-based heat sink

To address the concern of low thermal conductance of phase change materials (PCMs) that suppresses the performance of energy storage-based heat sinks for electronics,the apparent thermal conductivity of PCMs was increased by adding highly-conductive nanofillers and the potential in performance enhancement of such heat sinks was analyzed. Under a high heat load (heat flux was 10 W/cm2) within a short time period,the operation processes (melting and solidification heat transfer) of an energy storage-based heat sink using eicosane as the PCM with carbon nanotubes as the nanofillers are investigated numerically based on a three-dimensional model. The results show that due to the enhancement of apparent thermal conductivity of the PCM,the performance of the heat sink is improved with the increasing loading of carbon nanotubes and the extent of improvement is almost linearly correlated to the loading. When the volume fraction of carbon nanotubes is 10%,the maximum temperature rise on the cooling surface is lowered by 8 ℃ and the effective overall thermal resistance of the heat sink is decreased by 14%,as compared to those of the baseline case without carbon nanotubes,indicating that this is a promising approach to improving the performance of energy storage-based heat sinks．