Mathematical Modelling On Particle DiffusionIn Fluidised Beds And Dense TurbulentTwo-phase Flows

Volume-fraction weighted and Reynolds averaged momentum transport equations are solved in an Euler/Euler approach to numerically simulate the turbulent, dispersed two-phase flow in a two-dimensional channel and a three-dimensional conic diffuser flow. Particular attention is given to the modelling of turbulent diffusion and particle wall interaction, assuming local equilibrium, but introducing individual terms for particle/fluid drag interaction, particle collisions and trajectory crossings. These influences have been quantified in terms of partial viscosities, a restitution power and a turbulence structure parameter. Boussinesq approximations have been used for each phase and the formulation of their interaction was provided in the framework of the eddy-viscosity modelling concept.