Reignition phenomenon of high-speed hydrogen jet diffusion flame

✍ Scribed by Shuichi Torii; Byong-Koog Jung; Toshiaki Yano

• Publisher: John Wiley and Sons
• Year: 2002
• Tongue: English
• Weight: 236 KB
• Volume: 26
• Category: Article
• ISSN: 0363-907X
• DOI: 10.1002/er.833

✦ Synopsis

An experimental study deals with a high-speed hydrogen jet diffusion flame ejected vertically upward from a straight circular nozzle. Consideration is given to the reignition phenomenon that occurs after blow-off of the main flame. The Schlieren technique and image-processing method with the aid of the high-speed video camera are employed to visualize the flame shape, particularly the flame base near the nozzle tip and to investigate the time history of the flame morphology. It is found that: (i) the flame reignition phenomenon of hydrogen jet diffusion flames appears only in a certain region of mass flow rates; (ii) the small-sized flame-let remains in the vicinity of the nozzle rim at the mass flow rates that the reignition occurs; (iii) a further increase in mass flow rates makes the flame-let extinguish and no reignition occurs; (iv) the time interval of flame reignition extends with an increase in mass flow rates; and (v) the flow rates of the onset and end of the reignition and the existence of flame-let formed near the nozzle rim are affected by the rim thickness of the fuel nozzle.