Noise sources in swirl burners

Gupta, Ankush; Syred, N.; Béer, J.M.

doi:10.1016/0003-682x(76)90006-2

Cited by 83 publications

(131 citation statements)

References 2 publications

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“…The existence of such a lean and cold zone leads to the formation of a PVC [4][5][6][7][8]. This PVC only occurs in the 2% case and precesses at 408Hz.…”

Section: Resultsmentioning

confidence: 99%

“…A key zone of the chamber controlling instabilities is the burner outlet section where swirl is very intense and must provide flame stabilisation. In these regions, the natural unstable modes of swirling flows (Precessing Vortex Cores or PVCs [4][5][6][7][8]) can interact with stabilisation and lift-off phenomena [9][10][11][12] to produce undesired oscillations.…”

Section: Introductionmentioning

confidence: 99%

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Large eddy simulation of piloting effects on turbulent swirling flames

Sengissen

Giauque

Staffelbach

et al. 2007

Proceedings of the Combustion Institute

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Pilot flames, created by additional injectors of pure fuel, are often used in turbulent burners to enhance flame stabilisation and reduce combustion instabilities. The exact mechanisms through which these additional rich zones modify the flame anchoring location and the combustion dynamics are often difficult to identify, especially when they include unsteady hydrodynamic motion. This study presents Large Eddy Simulations (LES) of the reacting flow within a large-scale gas turbine burner for two different cases of piloting, where either 2 or 6 percent of the total methane used in the burner is injected through additional pilot flame lines. For each case, LES shows how the pilot fuel injection affects both flame stabilisation and flame stability. The 6 percent case leads to a stable flame and limited hydrodynamic perturbations in the initial flame zone. The 2 percent case is less stable, with a small-lift-off of the flame and a Precessing Vortex Core (PVC) in the cold stabilisation zone. This PVC traps some of the lean cold gases issuing from the pilot passage stream, changes the flame stabilisation point and induces instability.

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“…The existence of such a lean and cold zone leads to the formation of a PVC [4][5][6][7][8]. This PVC only occurs in the 2% case and precesses at 408Hz.…”

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Large eddy simulation of piloting effects on turbulent swirling flames

Sengissen

Giauque

Staffelbach

et al. 2007

Proceedings of the Combustion Institute

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“…The effect of weak swirl (S ≤ 0.4) is to increase the width of a free or confined jet flow: the enhancement rate in jet growth, entrainment, and decay is improved progressively as the degree of swirl increases. For high intensity swirl (S ≥ 0.6), strong radial and axial pressure gradients are set up near the nozzle exit, resulting in axial recirculation in the form of a central toroidal recirculation zone, which is also known as vortex breakdown [11]. With these fundamental flow phenomena that govern the evolution of a rectangular jet, the computational results for a swirling shear layer emerging from an under-expanded supersonic rectangular nozzle may be presented.…”

Section: Resultsmentioning

confidence: 99%

“…Swirling flows are widely applied to the design of various combustion chambers, spray nozzles, environmental units, among others. In liquid rocket engines and aircraft combustion chambers, swirl is induced in the injected propellants or fuel respectively as a means of flame stabilization and combustion efficiency improvement [11]. The change of nozzle exit configuration for passive jet excitation control has already proven to be effective in mixing enhancement by previous researchers [6, 10, 12, 13, 15, 18-21, 29, 33].…”

Section: Introductionmentioning

confidence: 99%

Passive Control of Supersonic Rectangular Jets through Boundary Layer Swirl

Han

Taghavi

Farokhi

2013

Int. J. Turbo Jet-Engines

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Mixing characteristics of under-expanded supersonic jets emerging from plane and notched rectangular nozzles are computationally studied using nozzle exit boundary layer swirl as a mean of passive flow control. The coupling of the rectangular jet instability modes, such as flapping, and the swirl is investigated. A threedimensional unsteady Reynolds-Averaged Navier-Stokes (RANS) code with shock adaptive grids is utilized. For plane rectangular nozzle with boundary layer swirl, the flapping and spanwise oscillations are captured in the jet's small and large dimensions at twice the frequencies of the nozzles without swirl. A symmetrical oscillatory mode is also observed in the jet with double the frequency of spanwise oscillation mode. For the notched rectangular nozzle with boundary layer swirl, the flapping oscillation in the small jet dimension and the spanwise oscillation in the large jet dimension are observed at the same frequency as those without boundary layer swirl. The mass flow rates in jets at 11 and 8 nozzle heights downstream of the nozzles increased by nearly 25% and 41% for the plane and notched rectangular nozzles respectively, due to swirl. The axial gross thrust penalty due to induced swirl was 5.1% for the plane and 4.9% for the notched rectangular nozzle.

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“…Axial and tangential velocity profiles, if not measured, were often assumed to be simple flat, linear or parabolic profiles. Such approaches eliminate the need to model the inlet systems directly, but produce unreliable predictions ( Sloan et al, 1986;Dong and Lilley, 1994) The first studies on combustion in swirling flow were reviewed by Syred and Beér, 1974;Lilley, 1977;Gupta et al, 1984 and others. More recently, papers by Vanoverberghe et al, 2003 andMondal et al, 2004 included an extensive reference list with the most recent works on the subject.…”

Section: Introductionmentioning

confidence: 99%

A numerical investigation of the aerodynamics of a furnace with a movable block burner

Fudihara

Goldstein

Mori

2007

Braz. J. Chem. Eng.

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-In this work the air flow in a furnace was computationally investigated. The furnace, for which experimental test data are available, is composed of a movable block burner connected to a cylindrical combustion chamber by a conical quarl. The apertures between the movable and the fixed blocks of the burner determine the ratio of the tangential to the radial air streams supplied to the furnace. Three different positions of the movable blocks were studied at this time. A three-dimensional investigation was performed by means of the finite volume method. The numerical grid was developed by the multiblock technique. The turbulence phenomenon was addressed by the RNG k-ε model. Profiles of the axial, tangential and radial velocities in the combustion chamber were outlined. The map of the predicted axial velocity in the combustion chamber was compared with a map of the experimental axial velocity. The internal space of the furnace was found to be partially filled with a reverse flow that extended around the longitudinal axis. A swirl number profile along the furnace length is presented and shows an unexpected increase in the swirl in the combustion chamber.

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Noise sources in swirl burners

Cited by 83 publications

References 2 publications

Large eddy simulation of piloting effects on turbulent swirling flames

Large eddy simulation of piloting effects on turbulent swirling flames

Passive Control of Supersonic Rectangular Jets through Boundary Layer Swirl

A numerical investigation of the aerodynamics of a furnace with a movable block burner

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