深入研究了粒子空间分布对材料导热性能的影响,探索了有效导热通路形成的必要条件。为了解决任意体积分数、指定空间构型的代表体积元(RVE)建模难题,用空间分布势能函数来描述目标空间分布构型,设计了Monte Carlo可控空间分布算法,该算法能够有效生成包含团簇和网链结构的任意空间构型的RVE。模拟研究结果表明:相同体积分数下,网链构型较团簇构型更能有效地形成导热通路,具有更高的热导率;体积分数对有效导热通路能否形成有重要影响,仅当体积分数大于20%之后,才具备形成有效导热通路的条件;粒子间距只有小于一定水平时,导热通路才能有效形成,随着粒子间距的增加,热导率成指数衰减。一定量的体积分数和较有效的粒子分布是形成有效导热通路的两个必要条件,二者缺一不可。
The effect of the particle spatial distribution on the thermal conductivity of composites and the essential condition of the formation of the effective thermal conductive pathways were investigated.In order to solve the modeling problem of the representative volume element(RVE) with any volume fraction and specified spatial configuration,the strategy to describe the objective spatial distribution configuration by the spatial distribution potential-energy function was employed,and a Monte Carlo controllable spatial distribution algorithm was designed,which can effectively create the RVE containing cluster and network configurations with any volume fraction.The simulated results show that,at the same volume fraction,the network configuration is easier to form the thermal conductive pathways and features higher thermal conductivity than the cluster one does;the volume fraction plays a key role in the formation of the effective thermal conductive pathways,which can occur only when the volume fraction is larger than 20% and the distance between the particles is short to some extent;with the increasing distance between the particles,the thermal conduction decreases in an exponent form.Therefore,a given amount of volume fraction and relative effective distribution of particles become two essential conditions of the formation of the effective thermal conductive pathways.