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Article Dans Une Revue Combustion and Flame Année : 2016

A comprehensive experimental and modeling study of isobutene oxidation

Chong-Wen Zhou
  • Fonction : Auteur
Eoin O'Connor
  • Fonction : Auteur
Eric L Petersen
  • Fonction : Auteur
Trent A Deverter
  • Fonction : Auteur
Goutham Kukkadapu
  • Fonction : Auteur
Chih-Jen Sung
Fathi Khaled
  • Fonction : Auteur
Timothy Held
  • Fonction : Auteur

Résumé

Isobutene is an important intermediate in the pyrolysis and oxidation of higher-order branched alkanes, and is a component of commercial gasoline and diesel fuels. To better understand its combustion characteristics, a series of ignition delay times (IDTs) and laminar flame speed (LFS) measurements have been performed. In addition, speciation data recorded in a flow reactor for the pyrolysis and oxidation of isobutene is also reported. IDTs of isobutene oxidation were measured in four different shock tubes and in two rapid compression machines (RCMs) under conditions of relevance to practical combustors. The combination of shock tube and RCM data greatly expands the range of available validation data for isobutene oxidation models to pressures of 50 atm and temperatures in the range 666-1715 K. Isobutene flame speeds were measured experimentally at 1 atm and at unburned gas temperatures of 298-398 K over a wide range of equivalence ratios. For the flame speed results, there was good agreement between different facilities and the current model in the fuel-rich region. Ab initio chemical kinetics calculations were carried out to calculate rate constants for important reactions such as H-atom abstraction by hydroxyl and hydroperoxyl radicals and the decomposition of 2-methylallyl radicals. The M062X/6-311++G(d,p) method was used in the geometry optimizations, frequency calculations and potential energy surface scans for the individual hindered rotors. The electronic single point energies were calculated at the QCISD(T)/CBS level of theory. Conventional transition-state theory with an asymmetric Eckart tunneling correction was used to calculate the high-pressure limit rate constants in this work. The low-frequency torsional conserved modes were treated as hindered rotors using a Pitzer-Gwinn-like approximation to calculate the partition function. A comprehensive chemical kinetic mechanism has been developed to describe the combustion of isobutene and is validated by comparison to the present IDT, LFS and flow-reactor speciation measurements. Important reactions, highlighted via flux and sensitivity analyses, include: (a) hydrogen atom abstraction from isobutene by hydroxyl and hydroperoxyl radicals, and molecular oxygen; (b) radical-radical recombination reactions, including 2-methylallyl radical self
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Dates et versions

hal-02928387 , version 1 (02-09-2020)

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Chong-Wen Zhou, Yang Li, Eoin O'Connor, Kieran P Somers, Sébastien Thion, et al.. A comprehensive experimental and modeling study of isobutene oxidation. Combustion and Flame, 2016, 167, pp.353-379. ⟨10.1016/j.combustflame.2016.01.021⟩. ⟨hal-02928387⟩
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