CUED Publications database

Extracting flame describing functions in the presence of self-excited thermoacoustic oscillations

Balusamy, S and Li, LKB and Han, Z and Hochgreb, S (2017) Extracting flame describing functions in the presence of self-excited thermoacoustic oscillations. Proceedings of the Combustion Institute, 36. pp. 3851-3861. ISSN 1540-7489

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Abstract

The determination of the acoustic response of flames as an element in acoustic network in the form of a flame describing function is one of the main elements in the prediction of thermoacoustic oscillations. The possibility to obtain a flame response through the usual methods of dynamic chemiluminescence and pressure measurements starting from an unforced system with incipient self-excitations at discrete frequencies from 20 to 400 Hz in the form of a stabilized flame at atmospheric pressure with a 700 mm tube as a combustor was investigated. Results showed that both the gain and phase can be entirely dominated by the behavior of the self-excitation thus extracting reliable gain and phase information is generally impossible as if the forced and self-excited modes acted linearly and independently. The phase information of the original flame became dominated by the triggered self-excitation although the gain was not significantly affected. Boundary conditions and systems utilized for flame acoustic forcing therefore need to be cautiously controlled when self-excitation occurs.

Item Type: Article
Subjects: UNSPECIFIED
Divisions: Div A > Energy
Depositing User: Cron Job
Date Deposited: 17 Jul 2017 19:19
Last Modified: 21 Sep 2017 01:40
DOI: