Direct numerical simulation of particle mixing in dispersed gas-liquid-solid flows using a combined volume of fluid and discrete particle approach

Dispersed gas-liquid-solid flows are frequently encountered in a variety of industrial processes involving a.o. coating, granulation, drying and synthesis of fuels (Fischer Tropsch) and base chemicals. The dynamics of these flows is dictated by the motion of the individual phases and the complex mutual interactions and as a direct consequence thereof CFD-based modelling of these systems has proven notoriously difficult. In literature both the Eulerian and Lagrangian method have been adopted to study multiphase flows. Although these computational methods are in principle well-suited to simulate the large-scale flow behaviour problems arise related to the representation of the interactions between the individual phases (closure problem). In this paper a novel simulation approach will be presented for dispersed gas-liquid-solid three phase flows accounting for i) all important mutual interactions between the phases ii) all relevant forces acting on the phases iii) the three-dimensional nature of the flow. In view of its fundamental nature, it is an important complementary tool in developing closure equations for the Eulerian approach.