Role of soret diffusion in the ignition of hydrogen/air mixtures by a heated kernel

Wenkai Liang, Chung King Law, Zheng Chen

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Scopus citations

Abstract

Effects of Soret diffusion on the minimum ignition energy of hydrogen/air mixtures by a heated kernel, and the associated flame structure, were investigated numerically with detailed chemistry and transport. Results show that Soret diffusion leads to larger (smaller) minimum ignition energy for relatively rich (lean) mixtures, and that this effect is mainly engendered by the Soret diffusion of H2, while that of the H radical is almost negligible. Mechanistically, Soret diffusion of H2 increases the fuel concentration entering the ignition kernel and consequently renders rich (lean) mixtures harder (easier) to ignite. The evolvement of the flame structure shows that before the H radical is substantially accumulated to exert an influence on the reaction zone, the high temperature gradient of the ignition initiation has driven H2in the mixture moving towards the ignition kernel. For the stretched spherical flame of the ignition, it is shown that Soret diffusion of both H and H2 should be included such that the stretched flame speed can be accurately predicted. At small flame radius (large strain rate), the Soret diffusion of H2 is the dominant mode of Soret diffusion; at large flame radius (small strain rate), the influence of Soret diffusion is similar to that on the unstretched adiabatic planar flame where the Soret diffusion of H radical plays the major role.

Original languageEnglish (US)
Title of host publication8th US National Combustion Meeting 2013
PublisherWestern States Section/Combustion Institute
Pages783-793
Number of pages11
ISBN (Electronic)9781627488426
StatePublished - Jan 1 2013
Event8th US National Combustion Meeting 2013 - Park City, United States
Duration: May 19 2013May 22 2013

Publication series

Name8th US National Combustion Meeting 2013
Volume1

Other

Other8th US National Combustion Meeting 2013
CountryUnited States
CityPark City
Period5/19/135/22/13

All Science Journal Classification (ASJC) codes

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

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  • Cite this

    Liang, W., Law, C. K., & Chen, Z. (2013). Role of soret diffusion in the ignition of hydrogen/air mixtures by a heated kernel. In 8th US National Combustion Meeting 2013 (pp. 783-793). (8th US National Combustion Meeting 2013; Vol. 1). Western States Section/Combustion Institute.