An analytical approximation for high-temperature autoignition times of higher alkanes

Journal Article · Sun Apr 15 04:00:00 EDT 2007 · Combustion and Flame

DOI:https://doi.org/10.1016/J.COMBUSTFLAME.2006.12.006· OSTI ID:20880641

Saxena, P; Peters, N; Williams, F A ^[1]

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1. Center for Energy Research, Department of Mechanical and Aerospace Engineering, University of California, San Diego, 9500, Gilman Drive, Department 0411, La Jolla, CA 92093 (United States)

It is shown that, above about 1000 K, ignition delay times for propane and all higher alkanes, as well as for a number of other fuels, can be calculated well by employing rate parameters of only three types of elementary steps, namely C{sub m}H{sub n} + HO{sub 2} {yields} C{sub m}H{sub n-1} + H{sub 2}O{sub 2}, H{sub 2}O{sub 2} + M{yields}2OH + M and 2HO{sub 2} {yields} H{sub 2}O{sub 2} + O{sub 2}, only the first of which is fuel specific, the other two clearly being common to all fuels. The prediction of this remarkably simple result relies on a steady-state approximation for HO{sub 2}, as well as steady states for more active radicals during induction. The resulting approximation to the chemistry exhibits a slow, finite-rate buildup of H{sub 2}O{sub 2} and removal of fuel during the induction period. The criterion employed for termination of the induction period is the complete depletion of the original fuel subject to the approximations introduced. Numerical comparisons of the ignition-time formula with the experiments show that the predictions work well not only for higher alkanes but also for propene and JP-10. The analytical approximation thus produces reasonable results for a wide range of fuels. (author)

• OSTI ID: 20880641
• Journal Information: Combustion and Flame, Journal Name: Combustion and Flame Journal Issue: 1-2 Vol. 149; ISSN CBFMAO; ISSN 0010-2180
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
ALKANES
AUTOIGNITION
BUILDUP
COMBUSTION KINETICS
COMPARATIVE EVALUATIONS
FORECASTING
HYDROGEN PEROXIDE
JET ENGINE FUELS
PROPANE
PROPYLENE
RADICALS
REMOVAL
STEADY-STATE CONDITIONS
TEMPERATURE RANGE 1000-4000 K