Experimental study of heat transfer between fluid flowing through fracture surface with tortuous seepage path

Under the dual challenges of energy demand and environmental protection, geothermal energy has broad application prospects because of their cleanliness and huge reserves. Understanding the flow and heat transfer process of fluid flowing through fractured rock is of importance for the utilization of geothermal resources. A more practical calculation equation for convective heat transfer coefficient is derived based on Newton's cooling equation and previous research. Samples with different seepage paths were prepared through 3D printing technology and cement mortar pouring method. The effect of seepage path tortuosity, aperture, and initial temperature on the characteristics of heat transfer were analyzed and discussed by conducting the seepage and heat transfer test. The experimental results show that the overall convective heat transfer coefficient of sample with seepage path are lower than those of sample with smooth fractures. The greater the tortuosity of seepage path, the greater the overall convective heat transfer coefficient. In addition, the correlation of tortuosity and C, n in the characteristic number equation is proposed, providing significant parameters for the study of hydraulic-mechanicalthermal coupling when fluid flowing through rock mass with high temperature. (C) 2022 Elsevier Ltd. All rights reserved.