Abstract
The coupling mechanism of seepage and heat transfer in high-temperature rock fractures controls the heat extraction ability of enhanced geothermal systems. Utilising the lattice Boltzmann method, a numerical model is proposed to capture this coupling, accounting for fluid temperature’s influence on kinematic viscosity and thermal diffusion coefficient in rough fractures. The model’s validity is confirmed through a classic example. The effect of rough fracture surface on the coupling mechanism of seepage and heat transfer was analysed. The relationship between the roughness of the fracture surface and the performance indicators of geothermal extraction was discussed. The results show that neglecting the roughness of the fracture surface would lead to a severe underestimation of water temperatures within the fractures. As the roughness of the fracture surface intensified, its thermal breakthrough time gradually increased while the heat recovery rate and heat production power decreased.
