Implementation and validation of effective thermal conductivity model of coal-rock mass with rough capillary pore structure under CT three-dimensional reconstruction

On the strength of the capillary physical equivalent model and heat transfer law of series-parallel combined structural unit, the calculation model of effective thermal conductivity of coal-rock mass is obtained. The model considers the effect of roughness, porosity factor and other factors on effective thermal conductivity. CT digital core technology is applied to reconstruct the 3D model of coal-rock mass, and one-way heat transfer numerical simulation is carried out according to the model. It indicates that the internal temperature of coal-rock mass is non-uniformly distributed under the influence of pore structure, and the isothermal surface of pore region bulges towards the boundary of heat flux. Comparing the calculated and simulated values under the same conditions, the average error percentage of the theoretical calculation model is 6.95%, and the model has outstanding prediction performance in porous media with medium porosity and regular pore distribution, which provides a reference for predicting the effective thermal conductivity of coal-rock mass.