Numerical analysis on particle dispersions of swirling gas-particle flow using a four-way coupled large eddy simulation

Abstract

Subgrid-scale (SGS) gas flow and particle-particle collision are closely related to the particle dispersions in swirling gas-particle flow. However, investigations which consider the four-way coupled large eddy simulation (LES) are scant. The objective of the present contribution is to propose firstly a novel particle SGS kinetic turbulent energy-granular temperature (SGS-kp-θp) model to describe the interactions of gas-particle, particle-gas and particle-particle collision based on the kinetic energy of granular flow. Reynolds stresses transport equations are modeled by the second-order moment strategy. Numerical analysis on particle hydrodynamics that effected by particle diameters using LES is carried out and validations by both experiment and OpenFoam software reported are in good agreements. Results of this study showed flow structures of micro and larger size particles ranging from 12.5 μm to 105 μm significantly differ in the vortex evolutions and coherent structures. SGS particles collision incurs on the additional particle energy dissipations. Micro-particle contributes to the formation of stable vortex indicating the excellent followability and incapable of exerting counteractivity on gas flow. SGS axial interactions between gas and medium size particle of dp = 30 μm is approximately 3.5 times larger than those of largest size particle of dp = 105 μm. Moreover, maximum energy dissipation caused by largest particle collision is 1.6 times larger than that of micro particle at developing flow region.