Effects of turbulence on flame structure and NOx emission of turbulent jet non-premixed flames in high-temperature air combustion

Hideaki Kobayashi, Ken Oono, Eun Seong Cho, Hirokazu Hagiwara, Yasuhiro Ogami, Takashi Niioka

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

Turbulent jet non-premixed flame under the conditions of High Temperature Air Combustion (HiCOT) was investigated. Air diluted with nitrogen was preheated up to about 1 300 K. Propane was injected through a fuel tube parallel to the preheated airflow. LDV measurement of turbulence, CH-PLIF for reaction zone visualization, and NOx concentration measurements in the burnt gas were performed and the relations between these characteristics were examined. Results showed that turbulence intensity generated by perforated plate installed upstream of the fuel tube was high at high-temperature airflow due to high velocity compared with that at room temperature airflow when the flow rate was controlled to keep the excess air ratio constant regardless of preheating. The reaction zone represented by the CH-PLIF images still had a thin structure even in the HiCOT condition of oxygen concentration of 8 vol.%. The flow turbulence in the combustion duct played a significant role in decreasing NOx emission. Due to turbulence, flame was broken and a bubble-like flame structure was generated, especially in the lifted flame cases, implying that the burning fuel lumps flow a considerable distance in air with a low oxygen concentration and generate uniform heat release profiles in HiCOT furnaces.

Original languageEnglish
Pages (from-to)286-292
Number of pages7
JournalJSME International Journal, Series B: Fluids and Thermal Engineering
Volume48
Issue number2
DOIs
Publication statusPublished - 2005 May 1

Keywords

  • CH-PLIF
  • High-temperature air combustion
  • NOx
  • Non-premixed flame
  • Turbulent flame

ASJC Scopus subject areas

  • Mechanical Engineering
  • Fluid Flow and Transfer Processes
  • Physical and Theoretical Chemistry

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