Self-excited noise generation from laminar methane/air premixed flames in thin annular jets

Jin, Seong-Ho and Chung, Suk-Ho (2003) Self-excited noise generation from laminar methane/air premixed flames in thin annular jets. In: 2003 Australian Symposium on Combustion & The 8th Australian Flames Days, 2003, Monash University.

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Abstract

Self-excited noise generation from laminar flames in thin annular jets of methane/air premixture have been investigated experimentally. Various flames were observed in this flow configuration, including conical shape flames, ring shape flames, steady crown shape flames, and oscillating crown shape flames. Self-excited noise with the total sound pressure level of about 70 dB was generated from the oscillating crown shape flames for the equivalence ratios larger than 0.95. Sound pressure and CH* chemiluminescence were measured by using a microphone and a photomultiplier tube. The frequency of generated noise was measured as functions of equivalence ratio and premixture velocity. A frequency doubling phenomenon has also been observed. The measured CH* chemiluminescence data were analysed from which the corresponding sound pressure has been calculated. By comparing the data with those of measured ones, the noise source can be attributed to the flame front fluctuation near the edge of the oscillating crown-shape flames. The flame stability regime was influenced sensitively to the supplying air through the inner tube.

Item Type:Conference or Workshop Item (Presentation)
Additional Information:Self-excited noise generation from laminar flames in thin annular jets of methane/air premixture have been investigated experimentally. Various flames were observed in this flow configuration, including conical shape flames, ring shape flames, steady crown shape flames, and oscillating crown shape flames. Self-excited noise with the total sound pressure level of about 70 dB was generated from the oscillating crown shape flames for the equivalence ratios larger than 0.95. Sound pressure and CH* chemiluminescence were measured by using a microphone and a photomultiplier tube. The frequency of generated noise was measured as functions of equivalence ratio and premixture velocity. A frequency doubling phenomenon has also been observed. The measured CH* chemiluminescence data were analysed from which the corresponding sound pressure has been calculated. By comparing the data with those of measured ones, the noise source can be attributed to the flame front fluctuation near the edge of the oscillating crown-shape flames. The flame stability regime was influenced sensitively to the supplying air through the inner tube.
Keywords:Self-excited flame, Laminar premixed flame, Annular jets
Subjects:H Engineering > H141 Fluid Mechanics
H Engineering > H340 Acoustics and Vibration
H Engineering > H311 Thermodynamics
Divisions:College of Science > School of Engineering
ID Code:6990
Deposited By: Seong-Ho Jin
Deposited On:29 Nov 2012 07:20
Last Modified:02 Sep 2014 09:13

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