面接触条件下胶结颗粒物导热系数模型优化

Optimization of surface contact-based thermal conductivity model of cemented particles

为了更好地探究岩土类胶结颗粒材料的导热系数变化规律,减少造成的热害问题,根据胶结颗粒物的结构特征,考虑颗粒物和胶结基质为混合物时的状态,并结合有效介质导热系数模型和面接触导热系数模型,构建了适用于岩土类胶结颗粒材料的有效导热系数计算模型。采用瞬态热线法测试了实验试块的导热系数,将预测值与实测结果和Maxwell-Eucken模型的计算结果对比后发现,两模型的导热系数计算值都随着孔隙率的增加而逐渐减小。4组测试数据结果显示,Maxwell-Eucken模型的导热系数计算结果平均值为0.17172W/(m·K),优化的导热系数计算模型结果平均值为0.17139 W/(m·K),说明优化的导热系数计算模型得出的结论与实际测试结果平均值(0.16922 W/(m·K))更接近,能够更好预测胶结颗粒物质的导热系数。

In order to explore better the variation law of thermal conductivity of geomaterials,and reduce the thermal damage caused by the problem,according to the structural characteristics of the cemented particles,combined with the effective medium thermal conductivity model and the surface contact thermal conductivity model,the effective thermal conductivity calculation model suitable for the geotechnical cemented particulate material was constructed,and the state of the particulate matter and the cementitious matrix were considered.The transient hot wire method was applied to test the thermal conductivity of the experimental test block,and the predicted values were compared with the measured results and the calculated results of the Maxwell-Eucken model.It was found that with the increase of porosity,the calculated values of the thermal conductivity of both models decrease gradually.The results of the four sets of test data show that the average digit of the calculated thermal conductivity of the Maxwell-Eucken model is 0.17172 W/(m·K),and the average figure of the calculated model of the optimized thermal conductivity is 0.17139 W/(m·K).It indicates that the conclusion of the optimized thermal conductivity calculation model is closer tothe actual average test result(0.16922 W/(m·K)),which can better predict the thermal conductivity of cemented particulate matter.