地热储层岩体粗糙裂隙的热流耦合效应研究OA北大核心CSTPCD

Concerning complex multiphysics coupling issues involved in geothermal extraction and improving mining efficiency,a numerical model of thermal-fluid coupling in rough rock fractures was constructed using the discrete element software 3DEC to address the seepage-heat transfer problem during extraction.Rock mass cracks with dif-ferent three-dimensional morphological characteristics were considered,and the water-rock temperature change law was simulated with a hydraulic opening of 19.17 μm at different flow rates.Results showed that,due to the bloc-king effect of the crack morphology,the temperature of the outlet on the rough surface gradually decreased,and the temperature of the outlet increased.The time required for the model to reach a steady state decreased with the in-crease in flow rate and convective heat transfer coefficient.The morphology of the fracture affects the temperature distribution of fluids and rocks.The cold front morphology of the rough fracture surface was closely related to the morphology of the fracture surface.The thermal breakthrough of smooth fissures was faster than that of rough fis-sures.Increasing the roughness of the fissure surface helped prolong the thermal breakthrough time.The total heat extraction rate from rough fracture surfaces was slightly higher than that from smooth fracture surfaces,and increas-ing flow rate and convective heat transfer coefficient significantly increased the total heat extraction rate.This study provides important parameters and guidance for the design of geothermal energy systems and can improve the effi-ciency of geothermal energy development and utilization.