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Enhanced liquid-gas mixing due to pulsating injection

Grosshans, Holger LU ; Szász, Robert-Zoltán LU and Fuchs, Laszlo LU (2015) In Computers & Fluids 107. p.196-204
Abstract
This paper considers the effects of intermittent injection of a liquid jet or spray on the initial break-up and mixing of one fluid with the surrounding ambient fluid. The aim of the analysis is to describe the physical process and indicate the mechanisms that control the mixing under different flow conditions (time-dependent injection and its frequency relative to the time scales of the flow) and fluid properties (density ratio), Schmidt number for a single phase case which is studied for comparison, or the Weber number for the two-phase cases. The computations use Large Eddy Simulation (LES) to account for turbulence, and either Volume Of Fluid (VOF) for the initial break-up or Lagrangian Particle Tracking (LPT) with droplet break-up... (More)
This paper considers the effects of intermittent injection of a liquid jet or spray on the initial break-up and mixing of one fluid with the surrounding ambient fluid. The aim of the analysis is to describe the physical process and indicate the mechanisms that control the mixing under different flow conditions (time-dependent injection and its frequency relative to the time scales of the flow) and fluid properties (density ratio), Schmidt number for a single phase case which is studied for comparison, or the Weber number for the two-phase cases. The computations use Large Eddy Simulation (LES) to account for turbulence, and either Volume Of Fluid (VOF) for the initial break-up or Lagrangian Particle Tracking (LPT) with droplet break-up model in the case of liquid droplets injected into the ambient gas. The results show that, depending on the physical properties of the liquid and ambient gas, the initial break-up and turbulent mixing can be enhanced substantially with intermittent injection. The numerical modeling is validated by recovering key results of experimental and analytical works. It can be observed that a main effect during the mixing is the suction of ambient fluid at the tail of the injected liquid, which depends on the fluid properties. Increased injection frequency shows to increase the mixing significantly during the initial transient phase. (C) 2014 The Authors. Published by Elsevier Ltd. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Pulsed injection, Air entrainment, Mixing, Jets, Sprays
in
Computers & Fluids
volume
107
pages
196 - 204
publisher
Elsevier
external identifiers
  • wos:000348746400015
  • scopus:84913553775
ISSN
0045-7930
DOI
10.1016/j.compfluid.2014.11.009
language
English
LU publication?
yes
id
7061aaf7-ed9c-437a-aa06-2a4d6216e7d4 (old id 5187317)
date added to LUP
2015-03-25 11:03:02
date last changed
2017-10-22 04:27:05
@article{7061aaf7-ed9c-437a-aa06-2a4d6216e7d4,
  abstract     = {This paper considers the effects of intermittent injection of a liquid jet or spray on the initial break-up and mixing of one fluid with the surrounding ambient fluid. The aim of the analysis is to describe the physical process and indicate the mechanisms that control the mixing under different flow conditions (time-dependent injection and its frequency relative to the time scales of the flow) and fluid properties (density ratio), Schmidt number for a single phase case which is studied for comparison, or the Weber number for the two-phase cases. The computations use Large Eddy Simulation (LES) to account for turbulence, and either Volume Of Fluid (VOF) for the initial break-up or Lagrangian Particle Tracking (LPT) with droplet break-up model in the case of liquid droplets injected into the ambient gas. The results show that, depending on the physical properties of the liquid and ambient gas, the initial break-up and turbulent mixing can be enhanced substantially with intermittent injection. The numerical modeling is validated by recovering key results of experimental and analytical works. It can be observed that a main effect during the mixing is the suction of ambient fluid at the tail of the injected liquid, which depends on the fluid properties. Increased injection frequency shows to increase the mixing significantly during the initial transient phase. (C) 2014 The Authors. Published by Elsevier Ltd.},
  author       = {Grosshans, Holger and Szász, Robert-Zoltán and Fuchs, Laszlo},
  issn         = {0045-7930},
  keyword      = {Pulsed injection,Air entrainment,Mixing,Jets,Sprays},
  language     = {eng},
  pages        = {196--204},
  publisher    = {Elsevier},
  series       = {Computers & Fluids},
  title        = {Enhanced liquid-gas mixing due to pulsating injection},
  url          = {http://dx.doi.org/10.1016/j.compfluid.2014.11.009},
  volume       = {107},
  year         = {2015},
}