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Title: A comprehensive iso-octane combustion model with improved thermochemistry and chemical kinetics

Abstract

Iso-Octane (2,2,4-trimethylpentane) is a primary reference fuel and an important component of gasoline fuels. Furthermore, it is a key component used in surrogates to study the ignition and burning characteristics of gasoline fuels. This paper presents an updated chemical kinetic model for iso-octane combustion. Specifically, the thermodynamic data and reaction kinetics of iso-octane have been re-assessed based on new thermodynamic group values and recently evaluated rate coefficients from the literature. The adopted rate coefficients were either experimentally measured or determined by analogy to theoretically calculated values. New alternative isomerization pathways for peroxy-alkyl hydroperoxide ($$\dot{O}$$OQOOH) radicals were added to the reaction mechanism. The updated kinetic model was compared against new ignition delay data measured in rapid compression machines (RCM) and a high-pressure shock tube. Our experiments were conducted at pressures of 20 and 40 atm, at equivalence ratios of 0.4 and 1.0, and at temperatures in the range of 632–1060 K. The updated model was further compared against shock tube ignition delay times, jet-stirred reactor oxidation speciation data, premixed laminar flame speeds, counterflow diffusion flame ignition, and shock tube pyrolysis speciation data available in the literature. Finally, the updated model was used to investigate the importance of alternative isomerization pathways in the low temperature oxidation of highly branched alkanes. When compared to available models in the literature, the present model represents the current state-of-the-art in fundamental thermochemistry and reaction kinetics of iso-octane; and thus provides the best prediction of wide ranging experimental data and fundamental insights into iso-octane combustion chemistry.

Authors:
ORCiD logo [1];  [2];  [1];  [1];  [3];  [4];  [3];  [1];  [1];  [2];  [4];  [4];  [2];  [1];  [2];  [3];  [1]
  1. King Abdullah Univ. of Science and Technology (KAUST), Thuwal (Saudi Arabia). Clean Combustion Research Center (CCRC)
  2. Univ. of Connecticut, Storrs, CT (United States). Dept. of Mechanical Engineering
  3. National Univ. of Ireland, Galway (Ireland). Combustion Chemistry Centre
  4. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE; National Science Foundation (NSF)
OSTI Identifier:
1361588
Alternate Identifier(s):
OSTI ID: 1415304
Report Number(s):
LLNL-JRNL-711699
Journal ID: ISSN 0010-2180
Grant/Contract Number:  
AC52-07NA27344
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Combustion and Flame
Additional Journal Information:
Journal Volume: 178; Journal Issue: C; Journal ID: ISSN 0010-2180
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; iso-octane; combustion kinetics; thermodynamics; gauche; alternative isomerisation

Citation Formats

Atef, Nour, Kukkadapu, Goutham, Mohamed, Samah Y., Rashidi, Mariam Al, Banyon, Colin, Mehl, Marco, Heufer, Karl Alexander, Nasir, Ehson F., Alfazazi, A., Das, Apurba K., Westbrook, Charles K., Pitz, William J., Lu, Tianfeng, Farooq, Aamir, Sung, Chih-Jen, Curran, Henry J., and Sarathy, S. Mani. A comprehensive iso-octane combustion model with improved thermochemistry and chemical kinetics. United States: N. p., 2017. Web. doi:10.1016/j.combustflame.2016.12.029.
Atef, Nour, Kukkadapu, Goutham, Mohamed, Samah Y., Rashidi, Mariam Al, Banyon, Colin, Mehl, Marco, Heufer, Karl Alexander, Nasir, Ehson F., Alfazazi, A., Das, Apurba K., Westbrook, Charles K., Pitz, William J., Lu, Tianfeng, Farooq, Aamir, Sung, Chih-Jen, Curran, Henry J., & Sarathy, S. Mani. A comprehensive iso-octane combustion model with improved thermochemistry and chemical kinetics. United States. doi:10.1016/j.combustflame.2016.12.029.
Atef, Nour, Kukkadapu, Goutham, Mohamed, Samah Y., Rashidi, Mariam Al, Banyon, Colin, Mehl, Marco, Heufer, Karl Alexander, Nasir, Ehson F., Alfazazi, A., Das, Apurba K., Westbrook, Charles K., Pitz, William J., Lu, Tianfeng, Farooq, Aamir, Sung, Chih-Jen, Curran, Henry J., and Sarathy, S. Mani. Sun . "A comprehensive iso-octane combustion model with improved thermochemistry and chemical kinetics". United States. doi:10.1016/j.combustflame.2016.12.029. https://www.osti.gov/servlets/purl/1361588.
@article{osti_1361588,
title = {A comprehensive iso-octane combustion model with improved thermochemistry and chemical kinetics},
author = {Atef, Nour and Kukkadapu, Goutham and Mohamed, Samah Y. and Rashidi, Mariam Al and Banyon, Colin and Mehl, Marco and Heufer, Karl Alexander and Nasir, Ehson F. and Alfazazi, A. and Das, Apurba K. and Westbrook, Charles K. and Pitz, William J. and Lu, Tianfeng and Farooq, Aamir and Sung, Chih-Jen and Curran, Henry J. and Sarathy, S. Mani},
abstractNote = {Iso-Octane (2,2,4-trimethylpentane) is a primary reference fuel and an important component of gasoline fuels. Furthermore, it is a key component used in surrogates to study the ignition and burning characteristics of gasoline fuels. This paper presents an updated chemical kinetic model for iso-octane combustion. Specifically, the thermodynamic data and reaction kinetics of iso-octane have been re-assessed based on new thermodynamic group values and recently evaluated rate coefficients from the literature. The adopted rate coefficients were either experimentally measured or determined by analogy to theoretically calculated values. New alternative isomerization pathways for peroxy-alkyl hydroperoxide ($\dot{O}$OQOOH) radicals were added to the reaction mechanism. The updated kinetic model was compared against new ignition delay data measured in rapid compression machines (RCM) and a high-pressure shock tube. Our experiments were conducted at pressures of 20 and 40 atm, at equivalence ratios of 0.4 and 1.0, and at temperatures in the range of 632–1060 K. The updated model was further compared against shock tube ignition delay times, jet-stirred reactor oxidation speciation data, premixed laminar flame speeds, counterflow diffusion flame ignition, and shock tube pyrolysis speciation data available in the literature. Finally, the updated model was used to investigate the importance of alternative isomerization pathways in the low temperature oxidation of highly branched alkanes. When compared to available models in the literature, the present model represents the current state-of-the-art in fundamental thermochemistry and reaction kinetics of iso-octane; and thus provides the best prediction of wide ranging experimental data and fundamental insights into iso-octane combustion chemistry.},
doi = {10.1016/j.combustflame.2016.12.029},
journal = {Combustion and Flame},
number = C,
volume = 178,
place = {United States},
year = {Sun Feb 05 00:00:00 EST 2017},
month = {Sun Feb 05 00:00:00 EST 2017}
}

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