Acta Mechanica Sinica

, 24:251

Studies on gas turbulence and particle fluctuation in dense gas-particle flows

Research Paper

DOI: 10.1007/s10409-008-0156-z

Cite this article as:
Zhou, L. & Zeng, Z. Acta Mech Sin (2008) 24: 251. doi:10.1007/s10409-008-0156-z

Abstract

Particle fluctuation and gas turbulence in dense gas-particle flows are less studied due to complexity of the phenomena. In the present study, simulations of gas turbulent flows passing over a single particle are carried out first by using RANS modeling with a Reynolds stress equation turbulence model and sufficiently fine grids, and then by using LES. The turbulence enhancement by the particle wake effect is studied under various particle sizes and relative gas velocities, and the turbulence enhancement is found proportional to the particle diameter and the square of velocity. Based on the above results, a turbulence enhancement model for the particle-wake effect is proposed and is incorporated as a sub-model into a comprehensive two-phase flow model, which is then used to simulate dilute gas-particle flows in a horizontal channel. The simulation results show that the predicted gas turbulence by using the present model accounting for the particle wake effect is obviously in better agreement with the experimental results than the prediction given by the model not accounting for the wake effect. Finally, the proposed model is incorporated into another two-phase flow model to simulate dense gas- particle flows in a downer. The results show that the particle wake effect not only enhances the gas turbulence, but also amplifies the particle fluctuation.

Keywords

Particle fluctuation Gas turbulence Dense gas-particle flows 

List of symbols

U

mean velocity

u, v

fluctuating velocity

uu

Reynolds stress

dp

particle diameter

k

kinetic energy

αp

particle volume fraction

ρ

density

β

drag coefficient

ε

kinetic energy dissipation rate

P

mean pressure

Θ

mean pseudo-temperature

θ

fluctuating pseudo-temperature

τ

stress

Superscript

“—”

averaged value

Subscripts

p

particle

g

gas

f

fluid

Copyright information

© Springer-Verlag 2008

Authors and Affiliations

  1. 1.Department of Engineering MechanicsTsinghua UniversityBeijingChina
  2. 2.Aeronautic and Mechanical Engineering CollegeNanchang Hangkong UniversityNanchangChina

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