A coupled Eulerian fluid phase-Eulerian solids phase-Lagrangian discrete particles hybrid model applied to gas-solids bubbling fluidized beds

Abstract

Because the traditional Eulerian-Eulerian approach and Lagrangian-Eulerian approach are essentially the description of dense gas-solid two-phase flow in two reference frames, it is natural to expect that these approaches are related. A coupled Eulerian fluid phase-Eulerian solids phase-Lagrangian discrete particle phase (CEEL) hybrid approach is proposed where transport equations of fluid phase and Eulerian solids phase are solved in an Eulerian framework and the discrete particle phase is represented as Lagrangian framework. In this CEEL model, the solid phase is described by Eulerian solids phase and Lagrangian discrete particle phase. The ghost phase is introduced to represent either Eulerian solids phase or discrete particle phase as the solid phase. The Eulerian solids phase properties are modeled by means of kinetic theory of granular flow with an impact velocity-dependent restitution coefficient as functions of granular temperature. The collisions of discrete particles are handled using a discrete element method. Simulations are carried out in a dense gas-solid bubbling fluidized bed. The predicted solids flux agrees with the experimental data. Such approaches to closure model building enforce the macroscopic conservation principles while attempting to accommodate local variations in momentum exchange due to bubble formation mechanisms in gas-solid fluidized beds.