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ID 31637
file
title alternative
High-Frequency Oscillatory Combustion in Tubular Flame Burners(Thermal Engineering)
creator
Shiraga, Yousuke
Ishii, Kazuhiro
Toh, Hidemi
subject
Oscillating Combustion
Swirl
Noise
Combustion
Burner
Tubular Flame
Acoustic Oscillation
Helmhortz Resonance
NDC
Technology. Engineering
abstract
High-frequency oscillatory combustion in tubular flame burners has been experimentally investigated using two prototype burners of 1MW and 2MW. Oscillatory combustion regions have been mapped in the plane of equivalence ratio and air flow rate, and pressures fluctuations also have been recorded. Results show that large-amplitude, high-frequency oscillatory combustion occurs for near stoichiometric mixtures and when the mean axial velocity exceeds about 5m/s. With increasing the air flow rate, the oscillatory combustion region gradually expands on both lean and rich sides. According to FFT analyses, the peak frequencies during the oscillatory combustion exceed 1000Hz. A simple analysis shows that these high frequencies cannot be explained on the basis of the Helmholtz resonator, or attributed to the axial mode of acoustic instability of the burner tube. These high frequencies can be explained on the basis of coupling of tangential and radial modes of acoustic instability of the burner tubes. Just before the onset of the intense oscillatory combustion, the fundamental tangential mode, which is of asymmetry, appears, and during the subsequent intense oscillatory combustion, higher radial modes appear coupled with the asymmetric and symmetric tangential modes. Since the first asymmetric tangential mode of acoustic instability seems to trigger the intense, high-frequency oscillatory combustion, it is suggested to design the burner as symmetric as possible, and in addition, to make the flame as round as possible.
journal title
日本機械学會論文集. B編
volume
Volume 75
issue
Issue 753
start page
1197
end page
1204
date of issued
2009-05-25
publisher
一般社団法人日本機械学会
issn
0387-5016
ncid
language
jpn
nii type
Journal Article
HU type
Journal Articles
DCMI type
text
format
application/pdf
text version
publisher
rights
社団法人日本機械学会
本文データは学協会の許諾に基づきCiNiiから複製したものである
relation is version of URL
http://ci.nii.ac.jp/naid/110007226604
department
Graduate School of Engineering