High temperature ignition and combustion enhancement by dimethyl ether addition to methane-air mixtures

Zheng Chen, Xiao Qin, Yiguang Ju, Zhenwei Zhao, Marcos Chaos, Frederick L. Dryer

Research output: Contribution to journalConference article

129 Scopus citations

Abstract

The effects of dimethyl ether (DME) addition on the high temperature ignition and burning properties of methane-air mixtures were studied experimentally and numerically. The results showed that for a homogeneous system, a small amount of DME addition to methane resulted in a significant reduction in the high temperature ignition delay. The ignition enhancement effect by DME addition was found to exceed that possible with equivalent amounts of hydrogen addition, and it was investigated by using radical pool growth and computational singular perturbation analysis. For a non-premixed methane-air system, it was found that two different ignition enhancement regimes exist: a kinetic limited regime and a transport limited regime. In contrast to the dramatic ignition enhancement in the kinetic limited regime, the ignition enhancement in the transport limited regime was significantly less effective. Furthermore, laminar flame speeds as well as Markstein lengths were experimentally measured for methane-air flames with DME addition. The results showed that the flame speed increases almost linearly with DME addition. However, the Markstein length and the Lewis number of the binary fuel change dramatically at small DME concentrations. Moreover, comparison between experiments and numerical simulations showed that only the most recent DME mechanism well reproduced the flame speeds of both DME-air and CH 4-air flames.

Original languageEnglish (US)
Pages (from-to)1215-1222
Number of pages8
JournalProceedings of the Combustion Institute
Volume31 I
Issue number1
DOIs
StatePublished - Jan 1 2007
Event31st International Symposium on Combustion - Heidelberg, Germany
Duration: Aug 5 2006Aug 11 2006

All Science Journal Classification (ASJC) codes

  • Chemical Engineering(all)
  • Mechanical Engineering
  • Physical and Theoretical Chemistry

Keywords

  • Dimethyl ether
  • Ignition enhancement
  • Laminar flame speed
  • Markstein length

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