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The Effect of Splitting Timing on Mixing in a Jet with Double Injections : A Large-Eddy Simulation Study

Hadadpour, Ahmad LU ; Jangi, Mehdi LU and Bai, Xue-Song LU (2018) In Flow, Turbulence and Combustion
Abstract
We present large-eddy simulation (LES) of a high-pressure gas jet that is injecting into a quiescent inert environment. The injection is through a nozzle with a diameter of 1.35 mm. Four injection strategies are considered in which the results of a single continuous injection case are compared with those of double injection cases with different injection splitting timing. In all double injection cases, the injection pulsing interval is kept the same, and the total injected mass is equal to that of the single injection case. On the other hand,
the splitting timing is varied to investigate the effects of various injection splitting strategies on the mixture formation and the penetration length of the jet. Results show that the jet... (More)
We present large-eddy simulation (LES) of a high-pressure gas jet that is injecting into a quiescent inert environment. The injection is through a nozzle with a diameter of 1.35 mm. Four injection strategies are considered in which the results of a single continuous injection case are compared with those of double injection cases with different injection splitting timing. In all double injection cases, the injection pulsing interval is kept the same, and the total injected mass is equal to that of the single injection case. On the other hand,
the splitting timing is varied to investigate the effects of various injection splitting strategies on the mixture formation and the penetration length of the jet. Results show that the jet penetration length is not so sensitive to the splitting timing whereas the mixing quality can significantly change as a result of shifting the onset of injection splitting toward the end of injection. Especially, it is found that by adopting a post-injection strategy where a single injection splits into the main injection and late small injection near the end of injection period the mixing between the injected gas and ambient air is significantly improved. This trend is not as obvious when the injection splitting timing shifts toward the beginning or even in the middle of injection period. The increase of entrainment in the tail of each injection is one of the underlying physics in the mixing improvement in double injection cases. In addition to that, splitting a single injection into two smaller injections increases the surrounding area of the jet and also stretches it along the axial direction. It can potentially increase the mixing of injected gas with the ambient air. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
epub
subject
keywords
Multiple-injection, Post-injection, Diesel engine, Mixing, LES
in
Flow, Turbulence and Combustion
pages
15 pages
publisher
Springer
external identifiers
  • scopus:85045921128
ISSN
1573-1987
DOI
10.1007/s10494-018-9904-8
language
English
LU publication?
yes
id
f0a339e5-b760-4109-838b-39c77d8f2110
date added to LUP
2018-04-30 16:57:28
date last changed
2018-11-21 21:39:37
@article{f0a339e5-b760-4109-838b-39c77d8f2110,
  abstract     = {We present large-eddy simulation (LES) of a high-pressure gas jet that is injecting into a quiescent inert environment. The injection is through a nozzle with a diameter of 1.35 mm. Four injection strategies are considered in which the results of a single continuous injection case are compared with those of double injection cases with different injection splitting timing. In all double injection cases, the injection pulsing interval is kept the same, and the total injected mass is equal to that of the single injection case. On the other hand,<br/>the splitting timing is varied to investigate the effects of various injection splitting strategies on the mixture formation and the penetration length of the jet. Results show that the jet penetration length is not so sensitive to the splitting timing whereas the mixing quality can significantly change as a result of shifting the onset of injection splitting toward the end of injection. Especially, it is found that by adopting a post-injection strategy where a single injection splits into the main injection and late small injection near the end of injection period the mixing between the injected gas and ambient air is significantly improved. This trend is not as obvious when the injection splitting timing shifts toward the beginning or even in the middle of injection period. The increase of entrainment in the tail of each injection is one of the underlying physics in the mixing improvement in double injection cases. In addition to that, splitting a single injection into two smaller injections increases the surrounding area of the jet and also stretches it along the axial direction. It can potentially increase the mixing of injected gas with the ambient air.},
  author       = {Hadadpour, Ahmad and Jangi, Mehdi and Bai, Xue-Song},
  issn         = {1573-1987},
  keyword      = {Multiple-injection,Post-injection,Diesel engine,Mixing,LES},
  language     = {eng},
  month        = {04},
  pages        = {15},
  publisher    = {Springer},
  series       = {Flow, Turbulence and Combustion},
  title        = {The Effect of Splitting Timing on Mixing in a Jet with Double Injections : A Large-Eddy Simulation Study},
  url          = {http://dx.doi.org/10.1007/s10494-018-9904-8},
  year         = {2018},
}