Experimental and theoretical study of secondary acoustic instability of downward propagating flames: Higher modes and growth rates

Dubey, Ajit K.; Koyama, Yoichiro; Hashimoto, Nozomu; Fujita, Osamu

Experimental and theoretical study of secondary acoustic instability of downward propagating flames: Higher modes and growth rates

Dubey, Ajit K.; Koyama, Yoichiro; Hashimoto, Nozomu et al.

Combustion and flame, 2019, 205, 316-326

Permalink : https://hdl.handle.net/2115/82106

このアイテムのアクセス数:441件（2026-10-08 17:17 集計）

閲覧可能ファイル

ファイル	フォーマット	サイズ	閲覧回数	説明
Secondary instability_2nd Revision_Revise	pdf	664 KB	428

論文情報

ファイル出力 EndNote Basic出力 Mendeley出力

アクセス権	open access
URI	https://hdl.handle.net/2115/82106
タイトル	Experimental and theoretical study of secondary acoustic instability of downward propagating flames: Higher modes and growth rates
著者	Dubey, Ajit K. ; Koyama, Yoichiro ; Hashimoto, Nozomu ; Fujita, Osamu
著者名 Dubey, Ajit K.
著者名 Koyama, Yoichiro
著者名 Hashimoto, Nozomu
e-Rad_Researcher 10183930 著者名 Fujita, Osamu
言語	英語
キーワード	Secondary instability
	Downward propagating flames
	Combustion tube
	Parametric instability
	Lewis number
	Higher modes
発行日	2019-07
出版者	Elsevier
収録物名	Combustion and flame
巻(号)	205
ページ	316-326
抄録	Flames propagating in tubes open at the ignition end typically show two different kinds of thermo-acoustic instability namely, primary and secondary. Secondary acoustic instability is accompanied by parametric instability of flame front during which, cellular structures on the flame surface oscillate with half the acoustic frequency of excitation. The growth rates associated with secondary acoustic instability of flame structure are higher compared to primary instability of flames leading to very high peak pressures. In this work, we present experimental and theoretical study on parametric instability of downward propagating C2H4/O-2/CO2 flames at two different Le of 1.0 and 0.8. Lower Le mixtures are found to be more unstable. Parametric instability of higher acoustic modes is reported for the first time for gaseous fuels. Higher modes of parametric instability transitioned successively to lower modes as the flame propagated downward. Growth rate of parametric instability is measured in experiments. Theoretical prediction of growth rate is done based on velocity coupling mechanism. Theoretical calculations provide good approximation of growth rates and its variation with frequency.
資源タイプ	学術雑誌論文
出版タイプ	Accepted Manuscript
権利情報	Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International
権利情報	© 2019. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/
PISSN	0010-2180
関連情報 (isVersionOf)	出版社版DOI https://doi.org/10.1016/j.combustflame.2019.04.010