Comparative study of high-pressure fluid flow in densely packed granules using a 3D CFD model in a continuous medium and a simplified 2D DEM-CFD approach.

An isothermal compressible single-phase fluid flow through a non-homogeneous granular body composed of densely packed overlapping spheres imitating rock under high pressure was numerically studied using two different approaches. The first approach called the full 3D CFD model used the finite volume method (FVM) to solve the Reynolds-averaged Navier–Stokes equations using Reynolds stress model (BSL) in the continuous domain between the granulates. The model was verified, based on experimental and numerical results from the literature. The second approach was a simplified coupled DEM-CFD model based on a fluid flow network. The main aim of the work was to develop a validation procedure for simplified coupled DEM-CFD models due to the lack of experimental data for fluid flow characteristics in densely packed granules under extremely high-pressure conditions. First, a series of numerical simulations were performed for the fluid domain with the full 3D CFD model. The results of those simulations were next used to validate the 2D numerical results of the simplified coupled DEM-CFD model with respect to velocities, pressures, densities and flow rates. Almost the same pressure and density distributions and mass flow rates were obtained in both approaches. However, the fluid velocity was different due to the different fluid volumes in both fluid domains. The current simulation results constitute a reliable benchmark for validating other coupled 2D/3D DEM-CFD models that use a fluid flow network approach. [ABSTRACT FROM AUTHOR]