Author:
Greiffenhagen Felix,Woisetschläger Jakob,Gürtler Johannes,Czarske Jürgen
Abstract
Abstract
Modern, lean and premixed gas turbine combustion concepts for low NOx emissions are prone to combustion instabilities. In a previous work it was shown that laser interferometric vibrometry (LIV) can be used to record global as well as local heat release fluctuations in swirl-stabilized premixed methane flames quantitatively, if other effects influencing density are small. In this work a newly developed camera-based full-field LIV system (CLIV) was applied to a lean, confined, premixed and swirl-stabilized methane flame under atmospheric conditions. Instead of time-consuming pointwise scanning of the flame, CLIV records full-field line-of-sight density fluctuations with high spatio-temporal resolution. With a recording rate of 200 kHz, CLIV enables the visualization of highly unsteady processes in fluid dynamics and combustion research. As an example for an unsteady process, the propagation of the flame front through a lean, premixed gas volume is visualized during an ignition process. A discussion of algorithms and assumptions necessary to calculate heat release oscillations from density oscillations is presented and applied to phase-averaged data recorded with CLIV for this type of flame. As reference, OH* chemiluminescence data were recorded simultaneously. While density gradients travelling with the flow are recorded by LIV and CLIV, chemiluminescence imaging will show nothing in the absence of chemical reaction.
Graphic abstract
a Time-averaged density gradient within the combustor in lateral direction. b Density fluctuations along line-of-sight 7 ms after ignition. c Phase-averaged and local heat release fluctuations at 225 Hz perturbation frequency
Funder
Austrian Science Fund
Deutsche Forschungsgemeinschaft DFG
Publisher
Springer Science and Business Media LLC
Subject
Fluid Flow and Transfer Processes,General Physics and Astronomy,Mechanics of Materials,Computational Mechanics
Reference30 articles.
1. Balachandran R, Ayoola BO, Kaminski C, Dowling AP, Mastorakos E (2005) Experimental investigation of the nonlinear response of turbulent premixed flames to imposed inlet velocity oscillations. Combust Flame 143:37–55
2. Candel S, Durox D, Schuller T, Bourgouin J, Moeck JP (2014) Dynamics of swirling flames. Annu Rev Fluid Mech 46:147–173
3. Crighton DG, Dowling AP, Williams JEF, Heckl MA, Leppington FA (1996) Modern methods in analytical acoustics: lecture notes. Springer, London
4. Dowling AP, Yasser M (2015) Combustion noise. Proc Combust Inst 35:65–100
5. Fischer A, König J, Czarske J, Peterleithner J, Woisetschläger J, Leitgeb T (2013) Analysis of flow and density oscillations in a swirl-stabilized flame employing highly resolving optical measurement techniques. Exp Fluids 54:1622–1640
Cited by
7 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献