(1. College of Mining Engineering，Taiyuan University of Technology，Taiyuan，Shanxi 030024，China；2. Key Laboratory of In-situ Property-improving Mining of Ministry of Education，Taiyuan University of Technology，Taiyuan，Shanxi 030024，China)
Abstract：In the process of utilizing water injection heat exchange for the geothermal development of high-temperature rock mass，the surrounding high-temperature rock mass of the convective channel in the heat exchange will experience repeated cycles of cooling and heating. Under the cyclic temperature effect，the deformation of the fracture wall surface，fracture flow，and heat transfer characteristics of the high-temperature rock mass will be affected to a certain extent. To reveal the granite fracture seepage characteristics and forced convection heat transfer law in this complex process，the water seepage and heat transfer experiments were carried out in the laboratory under the cyclic cooling-heating process(300 ℃→250 ℃→200 ℃→150 ℃→300 ℃). The results showed that：(1) the injection of low-temperature water could induce damage and fracture of the high-temperature granite fracture surface. The roughness coefficient JRC of the fracture surface changed from the initial 14.51 to 21.03 after the cyclic process，and the maximum height difference ξ of the fracture surface profile increased from 2.2 mm to 3.21 mm. The flow-conducting fracture of the high-temperature rock mass became more tortuous and the roughness increased with the temperature change. (2) When the rock temperature decreased from 300 ℃ to 150 ℃，the fracture permeability decreased exponentially from the initial 1.63 Darcy to 0.53 Darcy. However，when the rock temperature increased from 150 ℃ to 300 ℃，the fracture closed due to the thermal expansion of the rock matrix，and the permeability further decreased. With the increase of the cooling-heating cycles，the overall fracture permeability fluctuated to a certain extent，eventually leading to a significant decrease in permeability. (3) A higher initial rock temperature and an increase in the injection water pressure for heat exchange were beneficial to the forced convection heat exchange effect of the high-temperature granite fracture. However，with the increase of the cooling-heating cycles，the effect of convection heat exchange weakened. This study has certain guiding significance and value for the efficient development of geothermal resources in the high-temperature rock mass and the control technology of convection heat exchange.
黄长松1，2，梁卫国1，2，陈跃都2，廖 涛1，2. 循环高温作用下花岗岩裂缝渗流–传热特性试验研究[J]. 岩石力学与工程学报, 2023, 42(9): 2253-2265.
HUANG Changsong1，2，LIANG Weiguo1，2，CHEN Yuedu2，LIAO Tao1，2. Experimental study on seepage and heat transfer characteristics of single fracture granite under high-temperature cycle conditions. , 2023, 42(9): 2253-2265.
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2023, Vol. 42 
