Thermoacoustic limit cycles in a premixed laboratory combustor with open and choked exits

Hield, Peter; Brear, Michael J.; Jin, Seong-Ho

doi:10.1016/j.combustflame.2009.05.011

Cited by 82 publications

(72 citation statements)

References 51 publications

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“…Further, the essential physics of thermoacoustic instabilities are not entirely understood [6,7]. This is mostly due to the complexities involved in the interactions between premixed flames and sound waves [9,10] and, to some extent, the effects of system boundaries [11,12].…”

Section: Introductionmentioning

confidence: 99%

Response of a conical, laminar premixed flame to low amplitude acoustic forcing – A comparison between experiment and kinematic theories

Karimi

2014

Energy

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This paper presents an experimental study on the dynamics of a ducted, conical, laminar premixed flame subjected to low amplitude acoustic excitation from upstream. The heat release response of the flame to velocity disturbances is investigated through measurement of the so called 'flame transfer function' for a wide range of forcing frequencies. The results are compared with those predicted by the existing linear kinematic theories. It is observed that these theories are in general agreement with the experiment, although there exist some disparities. A detailed comparison of the experimental data with the kinematic theories shows that the phase speed of flame disturbances has an essential influence upon the level of agreement between the theory and experiment. The data set presented in this work complements that reported in an earlier study. In keeping with others, visualisation of the excited flames clearly shows that the flame response includes waves on the flame front which are formed at the base and then convect along the flame.

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Section: Introductionmentioning

confidence: 99%

Response of a conical, laminar premixed flame to low amplitude acoustic forcing – A comparison between experiment and kinematic theories

Karimi

2014

Energy

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“…Combustion response transfer functions, or §ame describing functions (FDF), describe the magnitude and phase of heat release as a function of local unsteady pressure/velocity. They have been constructed from measurements of pressure/velocity and CH * chemiluminescence, used to approximate heat release [7]. Low-amplitude §uctuations tend to have a linear response in magnitude, which concurs with the use of linear input growth rates in classical models [5,8].…”

Section: Flame Describing Functionsmentioning

confidence: 99%

“…However, the combustion response at high-amplitude §uctua-tions reaches a saturation level, which (in conjunction with increased acoustic damping) allows the development of limit cycle behavior. The shift to nonlinear behavior has generally been linked to unsteady amplitude, Reynolds number, equivalence ratio, and forcing frequency [7].…”

Section: Flame Describing Functionsmentioning

confidence: 99%

“…Terms that are prime and bar represent perturbation and mean quantities, respectively. n and τ were speci¦cally mapped against root mean square (rms) velocity rather than the instantaneous oscillating velocity [7]. The strength of the measured correlation suggests combustion response follows amplitude rather than instantaneous velocity/pressure.…”

Section: Flame Describing Functionsmentioning

confidence: 99%

“…Hield et al treated gain and phase as functions of local amplitude and ¦tted them to an exponential curve to give a rudimentary nonlinear functional form [7]:…”

Section: Flame Describing Functionsmentioning

confidence: 99%

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Development of combustion response functions in a subscale high-pressure transverse combustor

Wierman

Pomeroy

Anderson

2016

Progress in Propulsion Physics

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Combustion response functions describe the magnitude and time lag behavior of a §ame in response to unsteady pressure and velocity. By understanding the feedback between unsteady §ow¦elds and heat release, the growth and decay of combustion instability can be better predicted. An automated data isolation and reduction method has been developed to generate meaningful graphical combustion response functions from a combination of pressure amplitude and various image analysis metrics. It was developed and tested using pressure measurements and high-speed imaging of combustion light taken from a single element at the midspan of an unstable high-pressure subscale transverse combustor. The code was used to isolate time slices of near stationary pressure amplitude and to process the corresponding images into combustion response approximated by aggregate intensity, intensity weighted spatial center, Proper Orthogonal Decomposition (POD), and Dynamic Mode Decomposition (DMD). Overall, the generated combustion response functions generally agreed with expected behavior of an element located at a ¦rst width (1W) velocity antinode and second width (2W) pressure antinode. Results from both POD and DMD successfully isolated the prominent spatial and temporal light emission behavior.

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Time-resolved temperature profile measurements in the exhaust of a single sector gas turbine combustor at realistic operating conditions

et al. 2020

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Records of the time-varying temperature profile at flight relevant operating conditions are acquired at the exit of a combustion chamber fitted with a staged, lean-burn fuel injector using high-speed laser induced fluorescence (LIF) at a sample rate of 10 kHz. Temperatures are estimated from the concentration dependent fluorescence of the hydroxyl (OH) radical under the assumption of local equilibrium. Beyond the time-series analysis, the acquired data is correlated with simultaneously acquired OH chemiluminescence sampled in the primary zone near the fuel injector. These analyses reveal a strong influence from the precessing vortex core, originating in the primary zone, on oscillations in the temperature profiles measured at the exit of the combustor.

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Thermoacoustic limit cycles in a premixed laboratory combustor with open and choked exits

Cited by 82 publications

References 51 publications

Response of a conical, laminar premixed flame to low amplitude acoustic forcing – A comparison between experiment and kinematic theories

Response of a conical, laminar premixed flame to low amplitude acoustic forcing – A comparison between experiment and kinematic theories

Development of combustion response functions in a subscale high-pressure transverse combustor

Time-resolved temperature profile measurements in the exhaust of a single sector gas turbine combustor at realistic operating conditions

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