Experimental investigation of flame spreading over pure methane hydrate in a laminar boundary layer

Yoshihiro Maruyama, Masaru Joe Fuse, Takeshi Yokomori, Ryo Ohmura, Shigeru Watanabe, Toru Iwasaki, Wataru Iwabuchi, Toshihisa Ueda

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21 Citations (Scopus)

Abstract

Flame spreading over pure methane hydrate in a laminar boundary layer is investigated experimentally. The free stream velocity (U) was set constant at 0.4 m/s and the surface temperature of the hydrate at the ignition (Ts) was varied between -10 and -80°C. Hydrate particle sizes were smaller than 0.5 mm. Two types of flame spreading were observed; "low speed flame spreading" and "high speed flame spreading". The low speed flame spreading was observed at low temperature conditions (Ts = -80 to -60°C) and temperatures in which anomalous self-preservation took place (Ts = -30 to -10°C). In this case, the heat transfer from the leading flame edge to the hydrate surface plays a key role for flame spreading. The high speed flame spreading was observed when Ts = -50 and -40°C. At these temperatures, the dissociation of hydrate took place and the methane gas was released from the hydrate to form a thin mixed layer of methane and air with a high concentration gradient over the hydrate. The leading flame edge spread in this premixed gas at a spread speed much higher than laminar burning velocity, mainly due to the effect of burnt gas expansion.

Original languageEnglish
Pages (from-to)2131-2138
Number of pages8
JournalProceedings of the Combustion Institute
Volume34
Issue number2
DOIs
Publication statusPublished - 2013 Jan 11

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Keywords

  • Flame spreading
  • Laminar boundary layer
  • Methane hydrate

ASJC Scopus subject areas

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

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