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Large Eddy Simulation of the fuel transport and mixing process in a scramjet combustor with rearwall-expansion cavity

Cai, Zun; Liu, Xiao; Gong, Cheng LU ; Sun, Mingbo; Wang, Zhenguo and Bai, Xue Song LU (2016) In Acta Astronautica 126. p.375-381
Abstract

Large Eddy Simulation (LES) was employed to investigate the fuel/oxidizer mixing process in an ethylene fueled scramjet combustor with a rearwall-expansion cavity. The numerical solver was first validated for an experimental flow, the DLR strut-based scramjet combustor case. Shock wave structures and wall-pressure distribution from the numerical simulations were compared with experimental data and the numerical results were shown in good agreement with the available experimental data. Effects of the injection location on the flow and mixing process were then studied. It was found that with a long injection distance upstream the cavity, the fuel is transported much further into the main flow and a smaller subsonic zone is formed inside... (More)

Large Eddy Simulation (LES) was employed to investigate the fuel/oxidizer mixing process in an ethylene fueled scramjet combustor with a rearwall-expansion cavity. The numerical solver was first validated for an experimental flow, the DLR strut-based scramjet combustor case. Shock wave structures and wall-pressure distribution from the numerical simulations were compared with experimental data and the numerical results were shown in good agreement with the available experimental data. Effects of the injection location on the flow and mixing process were then studied. It was found that with a long injection distance upstream the cavity, the fuel is transported much further into the main flow and a smaller subsonic zone is formed inside the cavity. Conversely, with a short injection distance, the fuel is entrained more into the cavity and a larger subsonic zone is formed inside the cavity, which is favorable for ignition in the cavity. For the rearwall-expansion cavity, it is suggested that the optimized ignition location with a long upstream injection distance should be in the bottom wall in the middle part of the cavity, while the optimized ignition location with a short upstream injection distance should be in the bottom wall in the front side of the cavity. By employing a cavity direct injection on the rear wall, the fuel mass fraction inside the cavity and the local turbulent intensity will both be increased due to this fueling, and it will also enhance the mixing process which will also lead to increased mixing efficiency. For the rearwall-expansion cavity, the combined injection scheme is expected to be an optimized injection scheme.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Fuel transport, LES, Mixing efficiency, OpenFOAM, Rearwall-expansion cavity
in
Acta Astronautica
volume
126
pages
7 pages
publisher
Elsevier
external identifiers
  • scopus:84969988114
  • wos:000382412200039
ISSN
0094-5765
DOI
10.1016/j.actaastro.2016.05.010
language
English
LU publication?
yes
id
92a3ab72-ff1c-4eae-b378-5e125d81d750
date added to LUP
2016-11-28 13:54:32
date last changed
2017-11-05 05:10:06
@article{92a3ab72-ff1c-4eae-b378-5e125d81d750,
  abstract     = {<p>Large Eddy Simulation (LES) was employed to investigate the fuel/oxidizer mixing process in an ethylene fueled scramjet combustor with a rearwall-expansion cavity. The numerical solver was first validated for an experimental flow, the DLR strut-based scramjet combustor case. Shock wave structures and wall-pressure distribution from the numerical simulations were compared with experimental data and the numerical results were shown in good agreement with the available experimental data. Effects of the injection location on the flow and mixing process were then studied. It was found that with a long injection distance upstream the cavity, the fuel is transported much further into the main flow and a smaller subsonic zone is formed inside the cavity. Conversely, with a short injection distance, the fuel is entrained more into the cavity and a larger subsonic zone is formed inside the cavity, which is favorable for ignition in the cavity. For the rearwall-expansion cavity, it is suggested that the optimized ignition location with a long upstream injection distance should be in the bottom wall in the middle part of the cavity, while the optimized ignition location with a short upstream injection distance should be in the bottom wall in the front side of the cavity. By employing a cavity direct injection on the rear wall, the fuel mass fraction inside the cavity and the local turbulent intensity will both be increased due to this fueling, and it will also enhance the mixing process which will also lead to increased mixing efficiency. For the rearwall-expansion cavity, the combined injection scheme is expected to be an optimized injection scheme.</p>},
  author       = {Cai, Zun and Liu, Xiao and Gong, Cheng and Sun, Mingbo and Wang, Zhenguo and Bai, Xue Song},
  issn         = {0094-5765},
  keyword      = {Fuel transport,LES,Mixing efficiency,OpenFOAM,Rearwall-expansion cavity},
  language     = {eng},
  month        = {09},
  pages        = {375--381},
  publisher    = {Elsevier},
  series       = {Acta Astronautica},
  title        = {Large Eddy Simulation of the fuel transport and mixing process in a scramjet combustor with rearwall-expansion cavity},
  url          = {http://dx.doi.org/10.1016/j.actaastro.2016.05.010},
  volume       = {126},
  year         = {2016},
}