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Title: Testing the validity of a mechanism describing the oxidation of binary n-heptane/toluene mixtures at engine operating conditions

Abstract

The purpose of this work is to evaluate the influence of the n-heptane/toluene ratio on the reactivity of binary toluene reference fuels (TRFs), through a combined experimental and numerical work. Novel experimental ignition delay time (IDT) data of three binary TRFs of varying n-heptane/toluene ratios have been obtained in a high-pressure shock tube and in a rapid compression machine at conditions relevant to novel engine operation. Measurements have been performed at two pressures (10 and 30 bar), and at three fuel/air equivalence ratios (0.5, 1.0 and 2.0) for TRF mixtures of 50%, 75% and 90% by volume toluene concentration, over the temperature range of 650–1450 K. It was found that, increasing the n-heptane content, led to an increase in reactivity and shorter measured IDTs. Reduced sensitivity to the equivalence ratio was observed at high temperatures, especially for high toluene content mixtures. A well validated detailed kinetic mechanism for TRF oxidation was utilized to provide further insight into the experimental evidence. The mechanism, which has recently been updated, was also assessed in terms of its validity, contributing thus to its continuous development. Reaction path analysis was performed to delineate critical aspects of toluene oxidation under the considered conditions. Moreoever, sensitivity analysismore » highlighted the interactions between the chemistry of the two TRF components, revealing toluene's character as a reactivity inhibitor mainly through the consumption of ÓH radicals.« less

Authors:
ORCiD logo [1];  [2]; ORCiD logo [3]; ORCiD logo [3]; ORCiD logo [4];  [1]; ORCiD logo [1];  [1];  [4]; ORCiD logo [3]; ORCiD logo [2]
  1. National Technical Univ. of Athens (NTUA) (Greece)
  2. National Univ. of Ireland, Galway (Ireland)
  3. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  4. Brandenburg Univ. of Technology, Cottbus (Germany)
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA); USDOE Office of Energy Efficiency and Renewable Energy (EERE), Bioenergy Technologies Office (EE-3B); USDOE Office of Energy Efficiency and Renewable Energy (EERE), Vehicle Technologies Office (EE-3V)
OSTI Identifier:
1566021
Report Number(s):
LLNL-JRNL-754752
Journal ID: ISSN 0010-2180; 941521
Grant/Contract Number:  
AC52-07NA27344
Resource Type:
Accepted Manuscript
Journal Name:
Combustion and Flame
Additional Journal Information:
Journal Volume: 199; Journal Issue: C; Journal ID: ISSN 0010-2180
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
30 DIRECT ENERGY CONVERSION; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Ignition delay time; High-pressure shock tube; Rapid compression machine; Toluene; n-heptane; Detailed kinetics

Citation Formats

Malliotakis, Zisis, Banyon, Colin, Zhang, Kuiwen, Wagnon, Scott, Rodriguez Henriquez, Jose Juan, Vourliotakis, George, Keramiotis, Christos, Founti, Maria, Mauss, Fabian, Pitz, William J., and Curran, Henry. Testing the validity of a mechanism describing the oxidation of binary n-heptane/toluene mixtures at engine operating conditions. United States: N. p., 2018. Web. doi:10.1016/j.combustflame.2018.10.024.
Malliotakis, Zisis, Banyon, Colin, Zhang, Kuiwen, Wagnon, Scott, Rodriguez Henriquez, Jose Juan, Vourliotakis, George, Keramiotis, Christos, Founti, Maria, Mauss, Fabian, Pitz, William J., & Curran, Henry. Testing the validity of a mechanism describing the oxidation of binary n-heptane/toluene mixtures at engine operating conditions. United States. doi:10.1016/j.combustflame.2018.10.024.
Malliotakis, Zisis, Banyon, Colin, Zhang, Kuiwen, Wagnon, Scott, Rodriguez Henriquez, Jose Juan, Vourliotakis, George, Keramiotis, Christos, Founti, Maria, Mauss, Fabian, Pitz, William J., and Curran, Henry. Fri . "Testing the validity of a mechanism describing the oxidation of binary n-heptane/toluene mixtures at engine operating conditions". United States. doi:10.1016/j.combustflame.2018.10.024. https://www.osti.gov/servlets/purl/1566021.
@article{osti_1566021,
title = {Testing the validity of a mechanism describing the oxidation of binary n-heptane/toluene mixtures at engine operating conditions},
author = {Malliotakis, Zisis and Banyon, Colin and Zhang, Kuiwen and Wagnon, Scott and Rodriguez Henriquez, Jose Juan and Vourliotakis, George and Keramiotis, Christos and Founti, Maria and Mauss, Fabian and Pitz, William J. and Curran, Henry},
abstractNote = {The purpose of this work is to evaluate the influence of the n-heptane/toluene ratio on the reactivity of binary toluene reference fuels (TRFs), through a combined experimental and numerical work. Novel experimental ignition delay time (IDT) data of three binary TRFs of varying n-heptane/toluene ratios have been obtained in a high-pressure shock tube and in a rapid compression machine at conditions relevant to novel engine operation. Measurements have been performed at two pressures (10 and 30 bar), and at three fuel/air equivalence ratios (0.5, 1.0 and 2.0) for TRF mixtures of 50%, 75% and 90% by volume toluene concentration, over the temperature range of 650–1450 K. It was found that, increasing the n-heptane content, led to an increase in reactivity and shorter measured IDTs. Reduced sensitivity to the equivalence ratio was observed at high temperatures, especially for high toluene content mixtures. A well validated detailed kinetic mechanism for TRF oxidation was utilized to provide further insight into the experimental evidence. The mechanism, which has recently been updated, was also assessed in terms of its validity, contributing thus to its continuous development. Reaction path analysis was performed to delineate critical aspects of toluene oxidation under the considered conditions. Moreoever, sensitivity analysis highlighted the interactions between the chemistry of the two TRF components, revealing toluene's character as a reactivity inhibitor mainly through the consumption of ÓH radicals.},
doi = {10.1016/j.combustflame.2018.10.024},
journal = {Combustion and Flame},
number = C,
volume = 199,
place = {United States},
year = {2018},
month = {11}
}

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