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

Jin, Seong-Ho, Joung, Jae-Hoon and Chung, Suk-Ho (2021) Self-excited noise generation from laminar methane/air premixed flames in thin annular jets. Experimental Thermal an Fluid Science, 122 . p. 110321. ISSN 0894-1777

Full content URL: https://doi.org/10.1016/j.expthermflusci.2020.1103...

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

Self-excited noise generation from laminar flames in thin annular jets of premixed methane/air has been investigated experimentally. Various flame shapes were observed in this flow configuration, including conical shaped flames, ring shaped flames, steady crown shaped flames, and oscillating crown shaped flames. Self-excited noise with a total sound pressure level of about 70dB was generated from the oscillating crown shaped flames for 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 a function of equivalence ratio and premixture velocity. A frequency doubling phenomenon has also been observed. The measured CH* chemiluminescence data were analysed and which the corresponding sound pressure has been calculated. By comparing the measured and calculated sound pressures, the noise source can be attributed to the flame front fluctuation near the edge of the oscillating crown shaped flames. The flame stability regime was influenced strongly by the mass flow rate of air through the inner tube.

Additional Information:Article Reference: ETF_110321
Keywords:Annular jet, Laminar premixed flame, Sound pressure, Stability
Subjects:H Engineering > H141 Fluid Mechanics
H Engineering > H341 Acoustics
H Engineering > H321 Turbine Technology
H Engineering > H311 Thermodynamics
H Engineering > H220 Environmental Engineering
Divisions:College of Science > School of Engineering
ID Code:42760
Deposited On:11 Dec 2020 12:00

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