Journal of Rock Mechanics and Geotechnical Engineering

New quantitative characterizations of flow and heat transfer in hot dry rock fracture

Author links open overlay panelTiancheng Zhang a b, Bing Bai a, Hongwu Lei a, Yan Zou a, Lu Shi a, Huiling Ci a b

Abstract

The overall heat transfer coefficient (OHTC) of rock fractures is a fundamental parameter for characterizing the heat transfer behavior of rock fractures in hot dry rock (HDR) geothermal mining. Although a number of practical formulas for heat transfer coefficients have been developed in the literature, there is still no widely accepted analytical solution. This paper constructs highly accurate analytical solutions for the temperatures of the inner fracture wall and the fluid. Then they are employed to develop new definition-based formulas (formula A and its simplification formula B) of the OHTC, which are well validated by the experimental and numerical simulation results. An empirical correlation formula of heat transfer coefficient is proposed based on the definition-based formulas which can be directly used in the numerical simulations of heat transfer in rock fractures. A site-scale application example of numerical simulation also demonstrates the effectiveness of the empirical correlation formula.

https://www.sciencedirect.com/science/article/pii/S167477552400475X