Ignition enhancement by addition of NO and NO2 from a N 2/O2 plasma torch in a supersonic flow

Kenichi Takita, Naoyuki Abe, Goro Masuya, Yiguang Ju

Research output: Contribution to journalConference articlepeer-review

58 Scopus citations


The effects of NO and NO2 produced by using a plasma jet (PJ) of a N2/O2 mixture on ignition of hydrogen, methane, and ethylene in a supersonic airflow were experimentally and numerically investigated. Numerical analysis of ignition delay time showed that the addition of a small amount of NO or NO2 drastically reduced ignition delay times of hydrogen and hydrocarbon fuels at a relatively low initial temperature. In particular, NO and NO2 were more effective than O radicals for ignition of a CH4/air mixture at 1200 K or lower. These ignition enhancement effects were examined by including the low temperature chemistry. Ignition tests by a N2/O2 PJ in a supersonic flow (M= 1.7) for using hydrogen, methane, and ethylene injected downstream of the PJ were conducted. The results showed that the ignitability of the N2/O 2 PJ is affected by the composition of the feedstock and that pure O2 is not the optimum condition for downstream fuel injection. This result of ignition tests with downstream fuel injection demonstrated a significant difference in ignition characteristics of the PJ from the ignition tests with upstream fuel injection.

Original languageEnglish (US)
Pages (from-to)2489-2496
Number of pages8
JournalProceedings of the Combustion Institute
Volume31 II
StatePublished - 2007
Event31st International Symposium on Combustion - Heidelberg, Germany
Duration: Aug 5 2006Aug 11 2006

All Science Journal Classification (ASJC) codes

  • General Chemical Engineering
  • Mechanical Engineering
  • Physical and Theoretical Chemistry


  • Ignition
  • Plasma torch
  • Radical
  • Scramjet
  • Supersonic combustion


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