Campus Units

Chemical and Biological Engineering, Mechanical Engineering

Document Type

Article

Research Focus Area

Catalysis and Reaction Engineering, Computational Fluid Dynamics

Publication Version

Submitted Manuscript

Publication Date

11-2018

Journal or Book Title

Acta Mechanica

DOI

10.1007/s00707-018-2267-3

Abstract

Velocity fluctuations in the carrier phase and dispersed phase of a dispersed multiphase flow are studied using particle-resolved direct numerical simulation. The simulations correspond to a statistically homogeneous problem with an imposed mean pressure gradient and are presented for Rem=20 and a wide range of dispersed phase volume fractions (0.1≤ϕ≤0.4) and density ratios of the dispersed phase to the carrier phase (0.001≤ρp/ρf≤1000) . The velocity fluctuations in the fluid and dispersed phase at the statistically stationary state are quantified by the turbulent kinetic energy (TKE) and granular temperature, respectively. It is found that the granular temperature increases with a decrease in the density ratio and then reaches an asymptotic value. The qualitative trend of the behavior is explained by the added mass effect, but the value of the coefficient that yields quantitative agreement is non-physical. It is also shown that the TKE has a similar dependence on the density ratio for all volume fractions studied here other than ϕ=0.1 . The anomalous behavior for ϕ=0.1 is hypothesized to arise from the interaction of particle wakes at higher volume fractions. The study of mixture kinetic energy for different cases indicates that low-density ratio cases are less efficient in extracting energy from mean flow to fluctuations.

Comments

This is a pre-print of an article published in Acta Mechanica. The final authenticated version is available online at DOI: 10.1007/s00707-018-2267-3. Posted with permission.

Copyright Owner

Springer-Verlag GmbH Austria, part of Springer Nature

Language

en

File Format

application/pdf

Published Version

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