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Title: Large eddy simulation of a reacting spray flame with multiple realizations under compression ignition engine conditions

Abstract

An n-dodecane spray flame (Spray A from Engine Combustion Network) was simulated using a detailed combustion model along with a dynamic structure LES model to evaluate its performance at engine-relevant conditions and understand the transient behavior of this turbulent flame. The liquid spray was treated with a traditional Lagrangian method and the gas-phase reaction was modeled using a detailed combustion model. A 103-species skeletal mechanism was used for the n-dodecane chemical kinetic model. Significantly different flame structures and ignition processes are observed for the LES compared to those of RANS predictions. The LES data suggests that the first ignition initiates in lean mixture and propagates to rich mixture, and the main ignition happens in rich mixture, preferable less than 0.14 in mixture fraction space. LES was observed to have multiple ignition spots in the mixing layer simultaneously while the main ignition initiates in a clearly asymmetric fashion. The temporal flame development also indicates the flame stabilization mechanism is auto-ignition controlled and modulated by flame propagation. Soot predictions by LES present much better agreement with experiments compared to RANS both qualitatively and quantitatively. Multiple realizations for LES were performed to understand the realization to realization variation and to establish best practicesmore » for ensemble-averaging diesel spray flames. The relevance index analysis suggests that an average of 2 and 5 realizations can reach 99\% of similarity to the target average of 16 realizations on the temperature and mixture fraction fields, respectively. However, more realizations are necessary for OH and soot mass fraction due to their high fluctuations.« less

Authors:
; ; ; ; ; ;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Vehicle Technologies Office (EE-3V)
OSTI Identifier:
1392000
DOE Contract Number:  
AC02-06CH11357
Resource Type:
Journal Article
Resource Relation:
Journal Name: Combustion and Flame; Journal Volume: 162; Journal Issue: 12
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Diesel; Engine Combustion Network; Ignition; Large eddy simulation; Spray A; n-Dodecane

Citation Formats

Pei, Yuanjiang, Som, Sibendu, Pomraning, Eric, Senecal, Peter K., Skeen, Scott A., Manin, Julien, and Pickett, Lyle M.. Large eddy simulation of a reacting spray flame with multiple realizations under compression ignition engine conditions. United States: N. p., 2015. Web. doi:10.1016/j.combustflame.2015.08.010.
Pei, Yuanjiang, Som, Sibendu, Pomraning, Eric, Senecal, Peter K., Skeen, Scott A., Manin, Julien, & Pickett, Lyle M.. Large eddy simulation of a reacting spray flame with multiple realizations under compression ignition engine conditions. United States. doi:10.1016/j.combustflame.2015.08.010.
Pei, Yuanjiang, Som, Sibendu, Pomraning, Eric, Senecal, Peter K., Skeen, Scott A., Manin, Julien, and Pickett, Lyle M.. Tue . "Large eddy simulation of a reacting spray flame with multiple realizations under compression ignition engine conditions". United States. doi:10.1016/j.combustflame.2015.08.010.
@article{osti_1392000,
title = {Large eddy simulation of a reacting spray flame with multiple realizations under compression ignition engine conditions},
author = {Pei, Yuanjiang and Som, Sibendu and Pomraning, Eric and Senecal, Peter K. and Skeen, Scott A. and Manin, Julien and Pickett, Lyle M.},
abstractNote = {An n-dodecane spray flame (Spray A from Engine Combustion Network) was simulated using a detailed combustion model along with a dynamic structure LES model to evaluate its performance at engine-relevant conditions and understand the transient behavior of this turbulent flame. The liquid spray was treated with a traditional Lagrangian method and the gas-phase reaction was modeled using a detailed combustion model. A 103-species skeletal mechanism was used for the n-dodecane chemical kinetic model. Significantly different flame structures and ignition processes are observed for the LES compared to those of RANS predictions. The LES data suggests that the first ignition initiates in lean mixture and propagates to rich mixture, and the main ignition happens in rich mixture, preferable less than 0.14 in mixture fraction space. LES was observed to have multiple ignition spots in the mixing layer simultaneously while the main ignition initiates in a clearly asymmetric fashion. The temporal flame development also indicates the flame stabilization mechanism is auto-ignition controlled and modulated by flame propagation. Soot predictions by LES present much better agreement with experiments compared to RANS both qualitatively and quantitatively. Multiple realizations for LES were performed to understand the realization to realization variation and to establish best practices for ensemble-averaging diesel spray flames. The relevance index analysis suggests that an average of 2 and 5 realizations can reach 99\% of similarity to the target average of 16 realizations on the temperature and mixture fraction fields, respectively. However, more realizations are necessary for OH and soot mass fraction due to their high fluctuations.},
doi = {10.1016/j.combustflame.2015.08.010},
journal = {Combustion and Flame},
number = 12,
volume = 162,
place = {United States},
year = {Tue Dec 01 00:00:00 EST 2015},
month = {Tue Dec 01 00:00:00 EST 2015}
}