岩土材料导热系数与孔隙率关系的数值模拟分析

Numerical simulation of relationship between thermal conductivity of geotechnical material and its porosity

采用有限元方法数值,模拟了岩土材料的导热系数与孔隙率之间的非线性关系。有限元模型中的固体骨架和孔隙根据孔隙率的大小随机生成,模型中的材料参数和单元属性用ANSYS中的APDL参数化语言赋值。根据有限元随机模拟断面的热流密度分布和稳态热传导傅立叶定律,计算在不同孔隙率条件下的等效导热系数。研究表明,岩土材料模型等效导热系数随着孔隙的增加而减小;并且当孔隙率大于逾渗值后,等效导热系数的减小梯度明显降低;含孔隙岩土材料的热传导特性与渗流一样具有逾渗特性。

The relationship between thermal conductivity of geotechnical material and its porosity is simulated by using finite element method. The solid matrix and pore are generated randomly according to material porosity,and material parameters and element properties are changed by ANSYS parameter design language. The effective thermal conductivity is computed according to thermal flux through some section computed by FEM and Fourier heat transform low. The investigation shows that the effective thermal conductivity decreases with increasing porosity,and the gradient increment of effective thermal conductivity with respect to porosity ratio may decrease obviously while the porosity reaches percolation critical value,and the thermal conductivity characteristics of geotechnical materials pose the percolation transform properties that are the same as seepage in porous medium.