Extended LBM-DEM and LBM-DEM-FSLBM model for gas migration through bidisperse suspensions

Gas migration and retention in viscoelastic sediments is significant in many environmental and industrial settings. An extended LBM-DEM-VOF model is used to capture how gas influences sediment bed rheology based on the lattice Boltzmann modelling framework waLBerla, the discrete element method with interparticle lubrication, and the free surface LBM for liquid-gas interfaces. Modelling fluid-particle interactions is shown to be important due to the hydrodynamic forces involved in particle collisions. Fluid-particle interactions are studied using the momentum exchange method, with results showing good accuracy for different boundary condition schemes. The model is also applied to mono and bidisperse packed bed simulations to explore pressure drop. Good agreement with the Ergun equation is obtained for monodisperse beds, while well mixed bidisperse beds have a linear pressure drop and segregated beds two clearly defined regions. The ability of the lattice Boltzmann framework to capture complex fluid-particle interactions is demonstrated by the results presented.