Hokkaido University Collection of Scholarly and Academic Papers >
Graduate School of Engineering / Faculty of Engineering >
Peer-reviewed Journal Articles, etc >
Experimental and theoretical study of secondary acoustic instability of downward propagating flames: Higher modes and growth rates
This item is licensed under:Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International
Title: | Experimental and theoretical study of secondary acoustic instability of downward propagating flames: Higher modes and growth rates |
Authors: | Dubey, Ajit K. Browse this author | Koyama, Yoichiro Browse this author | Hashimoto, Nozomu Browse this author | Fujita, Osamu Browse this author →KAKEN DB |
Keywords: | Secondary instability | Downward propagating flames | Combustion tube | Parametric instability | Lewis number | Higher modes |
Issue Date: | Jul-2019 |
Publisher: | Elsevier |
Journal Title: | Combustion and flame |
Volume: | 205 |
Start Page: | 316 |
End Page: | 326 |
Publisher DOI: | 10.1016/j.combustflame.2019.04.010 |
Abstract: | 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. |
Rights: | © 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/ | http://creativecommons.org/licenses/by-nc-nd/4.0/ |
Type: | article (author version) |
URI: | http://hdl.handle.net/2115/82106 |
Appears in Collections: | 工学院・工学研究院 (Graduate School of Engineering / Faculty of Engineering) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
|
Submitter: 藤田 修
|