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LES/FGM investigation of ignition and flame structure in a gasoline partially premixed combustion engine

Xu, Leilei LU ; Zhang, Yan LU ; Tang, Qinglong ; Johansson, Bengt ; Yao, Mingfa and Bai, Xue Song LU (2023) In Proceedings of the Combustion Institute 39(4). p.4851-4860
Abstract

This paper presents a joint numerical and experimental study of the ignition process and flame structures in a gasoline partially premixed combustion (PPC) engine. The numerical simulation is based on a five-dimension Flamelet-Generated Manifold (5D-FGM) tabulation approach and large eddy simulation (LES). The spray and combustion process in an optical PPC engine fueled with a primary reference fuel (70% iso-octane, 30% n-heptane by volume) are investigated using the combustion model along with laser diagnostic experiments. Different combustion modes, as well as the dominant chemical species and elementary reactions involved in the PPC engines, are identified and visualized using Chemical Explosive Mode Analysis (CEMA). The results from... (More)

This paper presents a joint numerical and experimental study of the ignition process and flame structures in a gasoline partially premixed combustion (PPC) engine. The numerical simulation is based on a five-dimension Flamelet-Generated Manifold (5D-FGM) tabulation approach and large eddy simulation (LES). The spray and combustion process in an optical PPC engine fueled with a primary reference fuel (70% iso-octane, 30% n-heptane by volume) are investigated using the combustion model along with laser diagnostic experiments. Different combustion modes, as well as the dominant chemical species and elementary reactions involved in the PPC engines, are identified and visualized using Chemical Explosive Mode Analysis (CEMA). The results from the LES-FGM model agree well with the experiments regarding the onset of ignition, peak heat release rate and in-cylinder pressure. The LES-FGM model performs even better than a finite-rate chemistry model that integrates the full-set of chemical kinetic mechanism in the simulation, given that the FGM model is computationally more efficient. The results show that the ignition mode plays a dominant role in the entire combustion process. The diffusion flame mode is identified in a thin layer between the ultra fuel-lean unburned mixture and the hot burned gas region that contains combustion intermediates such as CO. The diffusion flame mode contributes to a maximum of 27% of the total heat release in the later stage of combustion, and it becomes vital for the oxidation of relatively fuel-lean mixtures.

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author
; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Chemical explosive mode analysis (CEMA), Combustion mode, Flamelet-generated manifold (FGM), Large eddy simulation (LES), Partially premixed combustion (PPC)
in
Proceedings of the Combustion Institute
volume
39
issue
4
pages
4851 - 4860
publisher
Elsevier
external identifiers
  • scopus:85138681199
ISSN
1540-7489
DOI
10.1016/j.proci.2022.07.214
language
English
LU publication?
yes
id
577ac0f3-4bb1-424a-a1f9-c51085ac8f04
date added to LUP
2022-12-20 11:31:00
date last changed
2023-11-07 00:48:26
@article{577ac0f3-4bb1-424a-a1f9-c51085ac8f04,
  abstract     = {{<p>This paper presents a joint numerical and experimental study of the ignition process and flame structures in a gasoline partially premixed combustion (PPC) engine. The numerical simulation is based on a five-dimension Flamelet-Generated Manifold (5D-FGM) tabulation approach and large eddy simulation (LES). The spray and combustion process in an optical PPC engine fueled with a primary reference fuel (70% iso-octane, 30% n-heptane by volume) are investigated using the combustion model along with laser diagnostic experiments. Different combustion modes, as well as the dominant chemical species and elementary reactions involved in the PPC engines, are identified and visualized using Chemical Explosive Mode Analysis (CEMA). The results from the LES-FGM model agree well with the experiments regarding the onset of ignition, peak heat release rate and in-cylinder pressure. The LES-FGM model performs even better than a finite-rate chemistry model that integrates the full-set of chemical kinetic mechanism in the simulation, given that the FGM model is computationally more efficient. The results show that the ignition mode plays a dominant role in the entire combustion process. The diffusion flame mode is identified in a thin layer between the ultra fuel-lean unburned mixture and the hot burned gas region that contains combustion intermediates such as CO. The diffusion flame mode contributes to a maximum of 27% of the total heat release in the later stage of combustion, and it becomes vital for the oxidation of relatively fuel-lean mixtures.</p>}},
  author       = {{Xu, Leilei and Zhang, Yan and Tang, Qinglong and Johansson, Bengt and Yao, Mingfa and Bai, Xue Song}},
  issn         = {{1540-7489}},
  keywords     = {{Chemical explosive mode analysis (CEMA); Combustion mode; Flamelet-generated manifold (FGM); Large eddy simulation (LES); Partially premixed combustion (PPC)}},
  language     = {{eng}},
  number       = {{4}},
  pages        = {{4851--4860}},
  publisher    = {{Elsevier}},
  series       = {{Proceedings of the Combustion Institute}},
  title        = {{LES/FGM investigation of ignition and flame structure in a gasoline partially premixed combustion engine}},
  url          = {{http://dx.doi.org/10.1016/j.proci.2022.07.214}},
  doi          = {{10.1016/j.proci.2022.07.214}},
  volume       = {{39}},
  year         = {{2023}},
}