TURBULENT GAS-SOLID FLOWS, PART I: DIRECT SIMULATIONS AND REYNOLDS STRESS CLOSURES

Abstract

This work deals with direct numerical simulation (DNS) and development of a new Reynolds stress model (RSM) for description of gas-solid turbulent flows with low volume fraction and high density ratio. The coupling between the two phases is "two-way," which allows investigation of the effects of the mass loading ratio and the particle time constant on both phases. DNS is conducted of a homogeneous turbulent shear flow laden with monosize particles using a Eulerian-Lagrangian formulation. The RSM is based on a "two-fluid" methodology in which both the carrier phase and the dispersed phase are considered in the Eulerian frame. Closures are suggested for the unclosed terms (including the pressure- velocity gradient) which manifest the effects of two-way coupling. The final model predictions for all the components of the fluid, the particle, and fluid-particle Reynolds stresses are assessed via detailed comparisons against DNS data.