Fluid mechanically coupled combustion instabilities in ramjet combustors

Hegde, U.; Reuter, D.; Zinn, B. T.; Daniel, B.R.

doi:10.2514/6.1987-216

Cited by 26 publications

(18 citation statements)

References 7 publications

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“…Many workers have investigated combustor geometries that include a predominant role for vortex-shedding, such as dump combustors involving axisymmetric backward-facing step (Poinsot et al 1987;Sivasegaram & Whitelaw 1987;Gutmark et al 1991;Sterling & Zukowski 1991;Yu et al 1991) and bluff-body flame-holders (Hegde et al 1987;Langhorne 1988;Macquistein & Dowling 1993). They have deduced the phase relationship between the vortex roll-up sequence and the heat-release fluctuations under conditions of excitation of intense oscillations.…”

Section: Introductionmentioning

confidence: 98%

Vortex-acoustic lock-on in bluff-body and backward-facing step combustors

Chakravarthy

Sivakumar

Shreenivasan

2007

Sadhana

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Experimental data on acoustic pressure measurements obtained over a wide range of conditions is reported for two simple geometries that are commonly studied for their combustion dynamics behaviour. These geometries are the confined bluff-body and the confined backward-facing steps. The data indicate regimes of flow-acoustic lock-on that signifies the onset of combustion instability, marked by the excitation of high-amplitude discrete tones of sound in the combustor. The highspeed chemiluminescence imaging of the combustion zone indicates heat-releaserate fluctuations occurring at the same frequencies as observed in the acoustic spectra. Attention is then devoted to the data obtained under cold-flow conditions to illustrate distinctly different behaviour than when combustion instability occurs, contrary to the commonly held view that the combustion process does not alter the underlying fluid mechanical processes under low-Mach number conditions.

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Section: Introductionmentioning

confidence: 98%

Vortex-acoustic lock-on in bluff-body and backward-facing step combustors

Chakravarthy

Sivakumar

Shreenivasan

2007

Sadhana

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“…This phenomenon of engine unstart is a serious technical problem encountered in a ramjet engine. In recent years, both experimental (e.g., Schadow et al, 1987Schadow et al, , 1990Gutmark et al, 1989Gutmark et al, , 1990Smith and Zukoski, 1985;Sterling and Zukoski, 1987;Hedge et al. 1987) and numerical (e.g., Menon and lou, 1987Menon and lou, , 1990Menon and lou, , 1991 lou and Menon, , 1990Kailasanath et al, 1989) investigations have been carried out to determine the mechanism of the combustion instability.…”

Section: Introductionmentioning

confidence: 99%

Active Combustion Control in a Ramjet Using Large-eddy Simulations

Menon

1992

GCST

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A large-eddy simulation model has been developed to study combustion instability in a ramjet combustor. A thin-flame model for premixed combustion is employed in the numerical scheme. which explicitly uses the local turbulent flame speed in the governing equation. Combustion instability in the ramjet has been numerically simulated. Two types of instability arc observed: a small-amplitude. highfrequency instability and a large-amplitude, low-frequency instability. Both such instabilities have been experimentally observed, and various computed flow features are in good qualitative agreement with experimental observations. The information obtained from these simulations has been used to develop an active control strategy to suppress the instability. Control of both types of combustion instability was successfully achieved using the acoustic feedback technique. and the control could be used to turn the instability on and off. The control is effective over a range of time delays, and the pressure fluctuation levels in the combustor are significantly reduced when active control is used.

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“…Classical considerations using the Rayleigh criterion have been used in the past (eg, Sterling and Zukoski, 1987;Hedge et al, 1987) to demonstrate that the unsteady fluctuations in heat release should be in-phase locally with the pressure fluctuations for the instability to occur. A local Rayleigh param-…”

Section: Simulation Of Combustion Instabilitymentioning

confidence: 99%

“…In recent years, both experimental (e.g., Schadow et al, 1989;Smith and Zukoski, 1985;Hedge et al, 1987) and numerical (e.g., Jou, 1990, 1991;Jou and Menon, 1990) investigations have been conducted to determine the mechanism of the combustion instability. Attempts to control combustion instability using both passive and active control techniques have also been carried out in the past (Culick, 1989).…”

Section: Introductionmentioning

confidence: 99%

“…This phenomenon of engine unstart is a serious technical problem encountered in a ramjet engine. In recent years, both experimental (e.g., Schadow ct al., 19g7, 1990;Gutmark et a&L 1989, Smith and Zukoski, 1985Sterling and Zukoski, 1987;,Hedge et al, 1987) and numerical (e.g., Menon and iou, , 1990Menon and iou, , 1991Menon, 1987, 1990;Kailasanath et al, 1989) investigations have been carried out to determine the mechanism of the combustion instability. Attempts to control combustion instability using both passive and active control techniques have also been carried out in the past (see Culick, 1989, for a review).…”

Section: Introductionmentioning

confidence: 99%

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Active Control of Combustion Instability in a Ramjet Using Large-Eddy Simulations

Menon¹

1992

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Fluid mechanically coupled combustion instabilities in ramjet combustors

Cited by 26 publications

References 7 publications

Vortex-acoustic lock-on in bluff-body and backward-facing step combustors

Vortex-acoustic lock-on in bluff-body and backward-facing step combustors

Active Combustion Control in a Ramjet Using Large-eddy Simulations

Active Control of Combustion Instability in a Ramjet Using Large-Eddy Simulations

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