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Assessment of grid/filter size dependence in large eddy simulation of high-pressure spray flames

Zhong, Shenghui LU ; Xu, Leilei LU ; Xu, Shijie LU orcid ; Zhang, Yan LU ; Zhang, Fan LU ; Jiao, Kui ; Peng, Zhijun and Bai, Xue Song LU (2022) In Fuel 329.
Abstract

With the increase of computing power, large eddy simulation (LES) within the Lagrangian–Eulerian two-phase flow framework has evolved as an useful numerical tool to gain insights to the spray combustion processes in advanced internal combustion engines. However, the inherent effect of grid/filter size (G/FS) on the physics revealed by LES is not fully understood. In this paper, we present several new viewpoints on this by analyzing the results from a Lagrangian–Eulerian LES study of Engine Combustion Networks Spray A with a newly developed multi-region adaptive mesh refinement method in OpenFOAM. It is found that G/FS affects the predicted spray characteristics, the modes of spray combustion, the ignition delay time and the liftoff... (More)

With the increase of computing power, large eddy simulation (LES) within the Lagrangian–Eulerian two-phase flow framework has evolved as an useful numerical tool to gain insights to the spray combustion processes in advanced internal combustion engines. However, the inherent effect of grid/filter size (G/FS) on the physics revealed by LES is not fully understood. In this paper, we present several new viewpoints on this by analyzing the results from a Lagrangian–Eulerian LES study of Engine Combustion Networks Spray A with a newly developed multi-region adaptive mesh refinement method in OpenFOAM. It is found that G/FS affects the predicted spray characteristics, the modes of spray combustion, the ignition delay time and the liftoff length in different ways. First, owing to the nature of Lagrangian particle-in-cell approach, the spray liquid penetration length converges as the G/FS approaches to the nozzle diameter. The convergence behavior is rather independent of the spray model parameters. Second, it is critical to have a well resolved spray liquid region; the main spray combustion characteristics, e.g., the mean pressure rise profile, the onsets of the cool flame and hot flame, and the main flame structure, are shown to be similar and independent of G/FS once the liquid region is properly resolved. However, the detailed flame structures at the liftoff position are sensitive to G/FS; the upstream auto-ignition events, the low temperature ignition assisted flame propagation and the hot flame propagation, are shown to partially rely on the adopted G/FS. Finally, it is found that a finer G/FS predicts a slower fuel/oxidizer mixing and a shorter flame liftoff length, yielding a higher soot mass.

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author
; ; ; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Adaptive mesh refinement, Engine Combustion Network, Grid/filter size dependence, Lagrangian–Eulerian method, Large eddy simulation, Spray flames
in
Fuel
volume
329
article number
125316
publisher
Elsevier
external identifiers
  • scopus:85135413039
ISSN
0016-2361
DOI
10.1016/j.fuel.2022.125316
language
English
LU publication?
yes
id
0762575b-873d-46bc-8f11-53f854649434
date added to LUP
2022-10-07 14:15:47
date last changed
2023-11-06 22:44:39
@article{0762575b-873d-46bc-8f11-53f854649434,
  abstract     = {{<p>With the increase of computing power, large eddy simulation (LES) within the Lagrangian–Eulerian two-phase flow framework has evolved as an useful numerical tool to gain insights to the spray combustion processes in advanced internal combustion engines. However, the inherent effect of grid/filter size (G/FS) on the physics revealed by LES is not fully understood. In this paper, we present several new viewpoints on this by analyzing the results from a Lagrangian–Eulerian LES study of Engine Combustion Networks Spray A with a newly developed multi-region adaptive mesh refinement method in OpenFOAM. It is found that G/FS affects the predicted spray characteristics, the modes of spray combustion, the ignition delay time and the liftoff length in different ways. First, owing to the nature of Lagrangian particle-in-cell approach, the spray liquid penetration length converges as the G/FS approaches to the nozzle diameter. The convergence behavior is rather independent of the spray model parameters. Second, it is critical to have a well resolved spray liquid region; the main spray combustion characteristics, e.g., the mean pressure rise profile, the onsets of the cool flame and hot flame, and the main flame structure, are shown to be similar and independent of G/FS once the liquid region is properly resolved. However, the detailed flame structures at the liftoff position are sensitive to G/FS; the upstream auto-ignition events, the low temperature ignition assisted flame propagation and the hot flame propagation, are shown to partially rely on the adopted G/FS. Finally, it is found that a finer G/FS predicts a slower fuel/oxidizer mixing and a shorter flame liftoff length, yielding a higher soot mass.</p>}},
  author       = {{Zhong, Shenghui and Xu, Leilei and Xu, Shijie and Zhang, Yan and Zhang, Fan and Jiao, Kui and Peng, Zhijun and Bai, Xue Song}},
  issn         = {{0016-2361}},
  keywords     = {{Adaptive mesh refinement; Engine Combustion Network; Grid/filter size dependence; Lagrangian–Eulerian method; Large eddy simulation; Spray flames}},
  language     = {{eng}},
  publisher    = {{Elsevier}},
  series       = {{Fuel}},
  title        = {{Assessment of grid/filter size dependence in large eddy simulation of high-pressure spray flames}},
  url          = {{http://dx.doi.org/10.1016/j.fuel.2022.125316}},
  doi          = {{10.1016/j.fuel.2022.125316}},
  volume       = {{329}},
  year         = {{2022}},
}