多孔材料热导率通用计算方法

利用蒙特卡洛法对多孔材料的内部结构进行了重构,并验证了重构模型具有自相似性和标度不变性的分形特性.对重构的多孔材料模型进行网格划分,利用二值化原理识别网格中的固体基质和流体孔隙,构筑材料内部真实传热过程的串并联混合热阻阵列图,建立适用于各种均质和非均质多孔材料热导率的计算方法——二值化阵列法.基于该方法,对闭孔泡沫铝和硅酸铝耐火纤维材料的热导率进行了计算,并与文献中的实验测量值进行了比较,具有较好的一致性,验证了本方法的正确性和普适性.

General calculating method of thermal conductivity for porous materials

The structure of porous materials was reconstructed by using a Monte-Carlo method.It is verified that the reconstructed model has the fractal characteristics of self-similarity and scale-invariance.The reconstructed structure of porous materials was first meshed,and solid and fluid phases of the grids were identified by the binary theory.Then a series-parallel connection array model was established for the real heat transfer process.Finally a method of calculating the thermal conductivity of homogeneous and non-homogeneous porous materials,namely,the binary array method,was proposed.Closed-cell foam aluminum and alumina-silicate refractory fiber materials were taken as examples,and the binary array method was used to calculate their thermal conductivities.The calculated values fit well with experimental results respectively,proving the correctness and universality of the binary array method.