Modelling of the gas fluidization of a mixture of cohesive and cohesionless particles by a combined continuum and discrete model

Abstract

This paper presents a numerical study of the gas fluidization of a mixture of 45,000 cohesive and cohesionless particles (D=100 μm and ρ=1,440 kgm⁻³) using a Combined Continuum and Discrete Model (CCDM). In such a model, the motion of individual particles is obtained by solving Newton’s second law of motion and flow of continuum fluid by the local averaged Navier-Stokes equations. In this work, the cohesion among particles is caused by van der Waals interactions. The Hamaker constants are used to distinguish the cohesivity among particles so that finite values are assigned to cohesive particles and zero values to cohesionless particles. It is shown that the presence of cohesionless particles in an assembly of cohesive particles can improve their flowability and that sustainable fluidization can be achieved if the amount of cohesionless particles is sufficient.