A Multiscale Approach to Simulate Non‐Isothermal Multiphase Flow in Deformable Porous Materials

Abstract Coupled thermal, hydraulic, and mechanical processes in porous materials play important roles in several energy and environmental technologies. The Darcy‐Brinkman‐Biot (DBB) framework has proven effective in modeling multiphase fluid flow in deformable porous solids across both pore and Darcy scales, including in systems where fractures coexist with a porous matrix. In this study, we extend the DBB framework, originally designed for isothermal conditions, to address non‐isothermal problems by incorporating an energy conservation equation. The resulting solver, hybridBiotThermalInterFoam , enables simulations of coupled multiphase fluid flow, heat transfer, and solid deformation in hybrid‐scale systems containing both solid‐free regions and ductile porous domains. The new solver is validated through comparisons with analytical solutions and, also, against established heat transfer solvers chtMultiRegionFoam and compressibleInterFoam . Further, a series of 2D and 3D case studies, including two‐phase heat transfer in solid‐free, static, or deformable porous media, highlights the solver's capacity to simulate complex flow dynamics and heat transport in systems involving high mobility ratios, viscous fingering, and fracture propagation. Our results establish the feasibility of incorporating thermal effects in simulations of a wide variety of energy geotechnics and environmental applications, including enhanced hydrocarbon recovery, soil remediation, and enhanced geothermal energy systems.