Thermo‐Hydrodynamic Processes of Microparticles in Fractures: A CFD–DEM Approach

ABSTRACT Controlling fracture permeability plays a critical role in subsurface energy applications, particularly in geothermal energy production and enhanced carbon sequestration, where regulating fluid flow is essential. The use of microcapsules has become a promising solution to enhance fracture permeability by providing a controlled sealing mechanism. This study employs a coupled Computational Fluid Dynamics Discrete Element Method (CFD‐DEM) approach to investigate the thermo‐hydro transport behavior of microcapsules in fractured environments, focusing on the influence of temperature, particle size, and concentration. The results show that temperature significantly affects microcapsules transport dynamics, with low temperatures promoting clustering due to increasing fluid viscosity, while high temperatures lead to excessive dispersion and reduce sealing. The medium temperature conditions create a balance between mobility and clustering, which controls the sealing behavior to suit the desired goal. Additionally, large microcapsules exhibit stronger sealing characteristics, whereas small ones maintain high mobility but are less effective for sealing. An interesting stagnation effect is also observed for medium size microcapsules, where the interaction of drag, inertia, and gravity can contribute to the control of the sealing behavior of the particles. Furthermore, high microcapsule concentrations can enhance aggregation at low temperatures, but may cause over‐dispersion at high temperatures, due to the collisional forces between the particles. These findings are extremely valuable for devising conditions for particles suitable for different purposes in controlling the transport and sealing behavior of particles in fractures in geothermal environments.