Low-temperature speciation and chemical kinetic studies of n-heptane

Darshan M.A. Karwat, Scott W. Wagnon, Margaret S. Wooldridge, Charles K. Westbrook

Research output: Contribution to journalArticle

42 Scopus citations

Abstract

Although there have been many ignition studies of n-heptane-a primary reference fuel-few studies have provided detailed insights into the low-temperature chemistry of n-heptane through direct measurements of intermediate species formed during ignition. Such measurements provide understanding of reaction pathways that form toxic air pollutants and greenhouse gas emissions while also providing key metrics essential to the development of chemical kinetic mechanisms. This paper presents new ignition and speciation data taken at high pressure (9. atm), low temperatures (660-710. K), and a dilution of inert gases-to-molecular oxygen of 5.64 (mole basis). The detailed time-histories of 17 species, including large alkenes, aldehydes, carbon monoxide, and n-heptane were quantified using gas chromatography. A detailed chemical kinetic mechanism developed previously for oxidation of n-heptane reproduced experimentally observed ignition delay times reasonably well, but predicted levels of some important intermediate chemical species that were significantly different from measured values. Results from recent theoretical studies of low temperature hydrocarbon oxidation reaction rates were used to upgrade the chemical kinetic mechanism for n-heptane, leading to much better agreement between experimental and computed intermediate species concentrations. The implications of these results to many other hydrocarbon fuel oxidation mechanisms in the literature are discussed.

Original languageEnglish (US)
Pages (from-to)2693-2706
Number of pages14
JournalCombustion and Flame
Volume160
Issue number12
DOIs
StatePublished - Dec 1 2013
Externally publishedYes

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Keywords

  • Chemical kinetics
  • Ignition delay
  • N-Heptane
  • Rapid compression facility
  • Speciation

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Fuel Technology
  • Energy Engineering and Power Technology
  • Physics and Astronomy(all)

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