Annals of the Assembly for International Heat Transfer Conference 13

ISBN 1-56700-225-0 / CD 1-56700-226-9

Year 2006

Shuichi Torii
Department of Mechanical Engineering, Kagoshima University; and Department of Mechanical Engineering and Materials Science, Kumamoto University, JAPAN

Toshiaki Yano
Department of Mechanical Engineering, Kagoshima University, 1-21-40 Korimoto, Kagoshima, 890-0065, Japan

S. Matuda
Kagoshima University, Kagoshima, Japan

The present study deals with split flame and reignition phenomenon of subsonic jet diffusion flames. Consideration is given to the effect of nozzle rim thickness on the flame reignition and its characteristics. The hydrogen gas is employed as a fuel and its flame is visualized by the schlieren technique and is investigated by the temperature and concentration measurements. It is found that: (i) the reignition phenomenon of hydrogen jet diffusion flames, which is formed by the vertical micro-size nozzle, takes places in a certain region of nozzle diameter and mass flow rate, (ii) the small-sized flamelet (2∼3mm in diameter), which is maintained at higher temperature and at lower concentration of the hydrogen, appears in the vicinity of the nozzle rim, during which the reignition subsequent to the blowout of the main flame occurs, (iii) a further increase in mass flow rates makes the flamelet extinguish, resulting in no reignition, (iv) the intermittence of the flame reignition depends on the mass flow rate of the fuel, and (v) although there is no effect of rim thickness of the nozzle on the mass flow rates at both onset and end of the reignition phenomenon, its thickness influences the flamelet formed near the nozzle rim.

COM-16 pages DOI: 10.1615/IHTC13.p26.150 Download article

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