Numerical simulation of grid-generated turbulent particulate flow by three-dimensional Reynolds stress

A Kartushinsky,A Shablinsky,D Stock,I Shcheglov,M Hussainov,S Tisler,Y Rudi

doi:10.3176/proc.2013.3.02

A Kartushinsky, A Shablinsky + Show 5 more

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https://doi.org/10.3176/proc.2013.3.02

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Abstract

A three-dimensional (3D) Reynolds stress turbulence model based on 3D Reynolds-averaged Navier-Stokes equations has been elaborated for grid-generated turbulence in particulate downward flow arranged in the channel domain of the square cross section. The model presented considers both the enhancement and attenuation of turbulence by means of the additional terms of the transport equations of the normal Reynolds stress components. It allows us to carry out calculations covering the long distance of the channel length without using algebraic assumptions for various components of the Reynolds stress. The results obtained show the effects of particles and mesh size of the turbulence generating grids on turbulence modification. In particular, the presence of solid particles at the initial period of turbulence decay results in the pronounced enhancement of turbulence that diminishes appreciably downwards in the area of typical channel turbulent flow. As the results show, the character of modification of all three normal components of the Reynolds stress taking place at the initial period of turbulence decay are uniform almost all over the channel cross sections. The increase in the grid mesh size slows down the rate of the turbulence enhancement which is caused by particles.

Highlights

Turbulent gas-solid particle flows in channels have numerous engineering applications ranging from pneumatic conveying systems to coal gasifiers, chemical reactor design, and are one of the most thoroughly investigated subjects in the area of particulate flows
A three-dimensional (3D) Reynolds stress turbulence model based on 3D Reynolds-averaged Navier–Stokes equations has been elaborated for grid-generated turbulence in particulate downward flow arranged in the channel domain of the square cross section
The character of modification of all three normal components of the Reynolds stress taking place at the initial period of turbulence decay are uniform almost all over the channel cross sections

Summary

Introduction

Turbulent gas-solid particle flows in channels have numerous engineering applications ranging from pneumatic conveying systems to coal gasifiers, chemical reactor design, and are one of the most thoroughly investigated subjects in the area of particulate flows. These flows are very complex and influenced by various physical phenomena, such as particle–turbulence and particle–particle interactions, deposition, gravitational and viscous drag forces, particle rotation and lift forces, etc. The mutual effect of particles and a flow turbulence has been the subject of numerous theoretical studies during several decades. The results obtained by these models were validated by the experimental data on turbulent particulate free-surface flows (Shraiber et al, 1990)

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