Effect of diffusive thermal instability on intrinsic limits of counterflow flame, unstrained planar flame and flame ball

Takaki Akiba, Tomoya Okuno, Hisashi Nakamura, Takuya Tezuka, Susumu Hasegawa, Roman Fursenko, Sergey Minaev, Masao Kikuchi, Kaoru Maruta

Research output: Contribution to conferencePaper

Abstract

To clarify the effect of Lewis number (Le) on near lean-limit flame behaviors, counterflow flame experiments under microgravity and one-dimensional computations with a detailed reaction mechanism for unstrained planar flame, counterflow flame and flame ball were conducted using CH4/O2/Kr (Le = 0.7-0.8), CH4/O2/Xe (Le = 0.5) and CH4/H2/O2/Xe (Le = 0.3) mixtures. In microgravity experiments, rich varieties of flames were observed. It was also confirmed that the locations of flame regime on stretch rate-equivalence ratio plane were changed with the value of Le. In the computation, a new parameter, J, representing fuel flux, was introduced to support discussing comprehensive combustion limit theory which can cover intrinsic limits of unstrained planar flame, counterflow flame and flame ball. The J parameter for unstrained planar flames and flame ball were presented. Flame ball exhibited smaller value of J at an intrinsic lean limit than unstrained planar flame. Intrinsic limits of flame ball, unstrained planar flame and counterflow flame were summarized and it was confirmed that flame ball has the widest lean limits and the difference between the limits of flame ball and those of counterflow flame became larger with the decrease of Lewis number.

Original languageEnglish
Publication statusPublished - 2019 Jan 1
Event12th Asia-Pacific Conference on Combustion, ASPACC 2019 - Fukuoka, Japan
Duration: 2019 Jul 12019 Jul 5

Conference

Conference12th Asia-Pacific Conference on Combustion, ASPACC 2019
CountryJapan
CityFukuoka
Period19/7/119/7/5

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Energy Engineering and Power Technology
  • Fuel Technology
  • Condensed Matter Physics

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    Akiba, T., Okuno, T., Nakamura, H., Tezuka, T., Hasegawa, S., Fursenko, R., Minaev, S., Kikuchi, M., & Maruta, K. (2019). Effect of diffusive thermal instability on intrinsic limits of counterflow flame, unstrained planar flame and flame ball. Paper presented at 12th Asia-Pacific Conference on Combustion, ASPACC 2019, Fukuoka, Japan.