FDEM‐TH3D: A three‐dimensional coupled hydrothermal model for fractured rock

• Published in: International journal for numerical and analytical methods in geomechanics 2019-01, Vol.43 (1), p.415-440
• Main Authors: Yan, Chengzeng, Jiao, Yu‐Yong
• Format: Article
• Language: English
• Subjects: 3D finite discrete element method; Apertures; Computational fluid dynamics; Computer simulation; Conduction; Conduction heating; Conduction model; Conductive heat transfer; Convection; Discrete element method; Fluid flow; Fluids; fractured rock; Fractures; Heat conduction; Heat exchange; heat exchange between fluid and rock; Heat transfer; Heat transport; hydrothermal coupling; Rocks; seepage; Simulation; Three dimensional models; Transport; Viscosity; Water circulation
• ISSN: 0363-9061; 1096-9853
• DOI: 10.1002/nag.2869

Summary This paper proposes a three‐dimensional coupled hydrothermal model for fractured rock based on the finite‐discrete element method to simulate fluid flow and heat transport. The 3D coupled hydrothermal model is composed of three main parts: a heat conduction model for the rock matrix, a heat transfer model for the fluid in the fractures (including heat conduction and heat convection), and a heat exchange model between the rock matrix and the fluid in the fractures. Four examples with analytical solutions are provided to verify the model. A heat exchange experiment of circulating water in a cylindrical granite sample with one fracture is simulated. The simulation results agree well with the experimental results. The effects of the fracture aperture, fluid viscosity, and pressure difference on the heat exchange between the fluid and rock are studied. Finally, an application concerned with heat transport and fluid flow in fractured rock is presented. The simulation results indicate that the 3D fully coupled hydrothermal model can capture the fluid flow and temperature evolution of rocks and fluids.