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Large-eddy simulation of the injection timing effects on the dual-fuel spray flame

Xu, Shijie LU orcid ; Zhong, Shenghui LU ; Hadadpour, Ahmad LU ; Zhang, Yan LU ; Pang, Kar Mun ; Jangi, Mehdi LU ; Fatehi, Hesameddin LU and Bai, Xue Song LU (2022) In Fuel 310.
Abstract

Large-eddy simulations (LES) coupled with a partially-stirred reactor model and a finite-rate chemistry are carried out to investigate the effects of n-heptane injection timing on the methanol fueled dual-fuel (DF) combustion. Methanol is premixed with air in a constant volume chamber (T=1000 K, ρ=14.8 kg/m3) to form a homogeneous mixture (equivalence ratio ϕm of 0.3). Liquid fuel n-heptane is provided from a high pressure injector to mimic the pilot fuel injection in DF engines. First, mesh sensitivity analysis and LES model validation are conducted. The experimental data of Spray-H (n-heptane fueled) from the Engine Combustion Network is used for model validation. It is shown that the present mesh and LES model... (More)

Large-eddy simulations (LES) coupled with a partially-stirred reactor model and a finite-rate chemistry are carried out to investigate the effects of n-heptane injection timing on the methanol fueled dual-fuel (DF) combustion. Methanol is premixed with air in a constant volume chamber (T=1000 K, ρ=14.8 kg/m3) to form a homogeneous mixture (equivalence ratio ϕm of 0.3). Liquid fuel n-heptane is provided from a high pressure injector to mimic the pilot fuel injection in DF engines. First, mesh sensitivity analysis and LES model validation are conducted. The experimental data of Spray-H (n-heptane fueled) from the Engine Combustion Network is used for model validation. It is shown that the present mesh and LES model are capable of replicating the liquid and vapor penetration length, mixture fraction, temperature distribution, pressure rise profile and ignition delay time (IDT). Second, the effects of n-heptane injection timing are investigated, by varying the start of injection (SOI) time. The LES results reveal that there are three stage heat releases in the DF combustion. With the delay of SOI, the mass fraction of hydrogen peroxide in the ambient mixture increases, leading to an early formation of hydroxyl. Therefore, the two-stage IDTs of n-heptane decrease, while the ambient methanol IDT increases. Results also show the cool flame and high-temperature flame evolution after methanol auto-ignition. The cool flame disappears while the high-temperature flame is found near the injector nozzle, which leads to a relatively high heat release rate.

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author
; ; ; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Dual-fuel combustion, Engine Combustion Network, Ignition, Injection timing, Large eddy simulation
in
Fuel
volume
310
article number
122445
publisher
Elsevier
external identifiers
  • scopus:85119427862
ISSN
0016-2361
DOI
10.1016/j.fuel.2021.122445
language
English
LU publication?
yes
id
0d73c46a-3a9b-4cb1-b762-46903f3ccb5f
date added to LUP
2021-12-13 13:34:52
date last changed
2022-04-27 06:38:41
@article{0d73c46a-3a9b-4cb1-b762-46903f3ccb5f,
  abstract     = {{<p>Large-eddy simulations (LES) coupled with a partially-stirred reactor model and a finite-rate chemistry are carried out to investigate the effects of n-heptane injection timing on the methanol fueled dual-fuel (DF) combustion. Methanol is premixed with air in a constant volume chamber (T=1000 K, ρ=14.8 kg/m<sup>3</sup>) to form a homogeneous mixture (equivalence ratio ϕ<sub>m</sub> of 0.3). Liquid fuel n-heptane is provided from a high pressure injector to mimic the pilot fuel injection in DF engines. First, mesh sensitivity analysis and LES model validation are conducted. The experimental data of Spray-H (n-heptane fueled) from the Engine Combustion Network is used for model validation. It is shown that the present mesh and LES model are capable of replicating the liquid and vapor penetration length, mixture fraction, temperature distribution, pressure rise profile and ignition delay time (IDT). Second, the effects of n-heptane injection timing are investigated, by varying the start of injection (SOI) time. The LES results reveal that there are three stage heat releases in the DF combustion. With the delay of SOI, the mass fraction of hydrogen peroxide in the ambient mixture increases, leading to an early formation of hydroxyl. Therefore, the two-stage IDTs of n-heptane decrease, while the ambient methanol IDT increases. Results also show the cool flame and high-temperature flame evolution after methanol auto-ignition. The cool flame disappears while the high-temperature flame is found near the injector nozzle, which leads to a relatively high heat release rate.</p>}},
  author       = {{Xu, Shijie and Zhong, Shenghui and Hadadpour, Ahmad and Zhang, Yan and Pang, Kar Mun and Jangi, Mehdi and Fatehi, Hesameddin and Bai, Xue Song}},
  issn         = {{0016-2361}},
  keywords     = {{Dual-fuel combustion; Engine Combustion Network; Ignition; Injection timing; Large eddy simulation}},
  language     = {{eng}},
  publisher    = {{Elsevier}},
  series       = {{Fuel}},
  title        = {{Large-eddy simulation of the injection timing effects on the dual-fuel spray flame}},
  url          = {{http://dx.doi.org/10.1016/j.fuel.2021.122445}},
  doi          = {{10.1016/j.fuel.2021.122445}},
  volume       = {{310}},
  year         = {{2022}},
}