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Title: Autoignition and structure of nonpremixed CH{sub 4}/H{sub 2} flames: Detailed and reduced kinetic models

Abstract

The ignition dynamics and subsequent flame evolution of hydrogen-enriched methane mixtures are investigated numerically in a reacting vortex ring configuration. The CH{sub 4}/H{sub 2} combustion is studied using a detailed reaction mechanism (GRI-Mech v3.0) and two augmented reduced mechanisms (11-step and 12-step). The main objective of this study is to identify the extent that the current reduced mechanisms can go in replicating the dynamics of the ignition process and flame structure in an unsteady nonpremixed configuration. The parameters of the numerical simulations are adjusted such that flame ignition occurs during either the formation or the postformation of the ring. The quasi-steady state assumption for O in the 12-step reduced kinetic model leads to shorter ignition delay times than those in the other kinetic models. For formation-phase ignition runs, the flame structure near the stoichiometric region is captured well by the 12-step model compared to GRI-Mech 3.0. For postformation ignition runs, the 12-step model predicts larger heat release rates and main species mole fractions compared to GRI-Mech 3.0. The 11-step model predicts well the ignition delay time. At later times the fuel-rich side of the flame predicted by this reduced mechanism exhibits differences from the detailed model. Counterflow diffusion flame resultsmore » are used to further compare the fuel-rich chemistry for the detailed and augmented reduced kinetic models.« less

Authors:
;  [1]
  1. Department of Mechanical and Aerospace Engineering, University at Buffalo, State University of New York, Buffalo, NY 14260-4400 (United States)
Publication Date:
OSTI Identifier:
20685979
Resource Type:
Journal Article
Journal Name:
Combustion and Flame
Additional Journal Information:
Journal Volume: 144; Journal Issue: 1-2; Other Information: Elsevier Ltd. All rights reserved; Journal ID: ISSN 0010-2180
Country of Publication:
United States
Language:
English
Subject:
03 NATURAL GAS; METHANE; HYDROGEN; FLAMES; IGNITION; COMBUSTION KINETICS; MATHEMATICAL MODELS

Citation Formats

Safta, C, and Madnia, C K. Autoignition and structure of nonpremixed CH{sub 4}/H{sub 2} flames: Detailed and reduced kinetic models. United States: N. p., 2006. Web. doi:10.1016/j.combustflame.2005.07.001.
Safta, C, & Madnia, C K. Autoignition and structure of nonpremixed CH{sub 4}/H{sub 2} flames: Detailed and reduced kinetic models. United States. https://doi.org/10.1016/j.combustflame.2005.07.001
Safta, C, and Madnia, C K. 2006. "Autoignition and structure of nonpremixed CH{sub 4}/H{sub 2} flames: Detailed and reduced kinetic models". United States. https://doi.org/10.1016/j.combustflame.2005.07.001.
@article{osti_20685979,
title = {Autoignition and structure of nonpremixed CH{sub 4}/H{sub 2} flames: Detailed and reduced kinetic models},
author = {Safta, C and Madnia, C K},
abstractNote = {The ignition dynamics and subsequent flame evolution of hydrogen-enriched methane mixtures are investigated numerically in a reacting vortex ring configuration. The CH{sub 4}/H{sub 2} combustion is studied using a detailed reaction mechanism (GRI-Mech v3.0) and two augmented reduced mechanisms (11-step and 12-step). The main objective of this study is to identify the extent that the current reduced mechanisms can go in replicating the dynamics of the ignition process and flame structure in an unsteady nonpremixed configuration. The parameters of the numerical simulations are adjusted such that flame ignition occurs during either the formation or the postformation of the ring. The quasi-steady state assumption for O in the 12-step reduced kinetic model leads to shorter ignition delay times than those in the other kinetic models. For formation-phase ignition runs, the flame structure near the stoichiometric region is captured well by the 12-step model compared to GRI-Mech 3.0. For postformation ignition runs, the 12-step model predicts larger heat release rates and main species mole fractions compared to GRI-Mech 3.0. The 11-step model predicts well the ignition delay time. At later times the fuel-rich side of the flame predicted by this reduced mechanism exhibits differences from the detailed model. Counterflow diffusion flame results are used to further compare the fuel-rich chemistry for the detailed and augmented reduced kinetic models.},
doi = {10.1016/j.combustflame.2005.07.001},
url = {https://www.osti.gov/biblio/20685979}, journal = {Combustion and Flame},
issn = {0010-2180},
number = 1-2,
volume = 144,
place = {United States},
year = {Sun Jan 01 00:00:00 EST 2006},
month = {Sun Jan 01 00:00:00 EST 2006}
}