Direct Simulations of Mixing of Liquids with Density and Viscosity Differences

J. J. Derksen*

*Corresponding author for this work

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

Simulations of flow and scalar transport in stirred tanks operated in transitional and mildly turbulent regimes (Re = 3000-12000) are presented. The moderate Reynolds numbers allow the flow to be simulated directly, without the use of turbulence closure or subgrid-scale models. The Newtonian liquids that are blended have different densities and/or viscosities, and the emphasis is on how these differences affect mixing times. The density difference is characterized by a Richardson number (Ri) that varies in the range of 0-0.5. The kinematic viscosity ratio is between 1 and 4. The results show that mixing times increase steeply with increasing Ri and that changing the tank layout can partly mitigate this effect. The viscosity ratio has a much weaker influence on the mixing time.

Original languageEnglish
Pages (from-to)6948-6957
Number of pages10
JournalIndustrial & Engineering Chemistry Research
Volume51
Issue number19
Early online date23 Apr 2012
DOIs
Publication statusPublished - 2012

Keywords

  • LARGE-EDDY SIMULATIONS
  • STIRRED-TANK
  • FLUID-FLOW
  • TURBULENCE
  • IMPELLER
  • AUTOMATA
  • EQUATION
  • TURBINE
  • LDA

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