An experimental investigation of an acoustically excited laminar premixed flame

Kartheekeyan, S.; Chakravarthy, Satyanarayanan R.

doi:10.1016/j.combustflame.2006.04.014

Cited by 24 publications

(3 citation statements)

References 37 publications

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“…Determination of the FTF/FDF of flames to different types of flow perturbations is an active field of research and mostly relies on experimental and numerical means. Studies carried out on a variety of geometrical configurations including conical and dihedral flames stabilized on a burner rim, inverted conical flames interacting with a modulated shear layer, ducted 'V' flames and swirling 'V' flames anchored on a central rod, 'M'-shaped flames as well as flames impinging on plates or lateral walls have provided much information on the underlying mechanisms and on the flame response to incoming velocity perturbations (Ducruix, Durox & Candel 2000;Durox, Schuller & Candel 2005;Chapparro, Landry & Cetegen 2006;Kartheekeyan & Chakravarthy 2006;Kornilov, Schreel & de Goey 2007;Cuquel, Durox & Schuller 2013b).…”

Section: Transfer Functions Of Laminar Premixed Flamesmentioning

confidence: 99%

Dynamics and control of premixed combustion systems based on flame transfer and describing functions

2020

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Section: Transfer Functions Of Laminar Premixed Flamesmentioning

confidence: 99%

Dynamics and control of premixed combustion systems based on flame transfer and describing functions

2020

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“…Upon switching to the central fuel injection, the bluish spectrum extends at the flame base to fill the whole combustor cross-section (as shown by the image in Figure 11(b)), where the overall reaction zone extends in the vertical plane to get the bluish spectrum across a corrugated envelope. In this concern, Kartheekeyan and Chakravarthy 39 stated that the fluctuation in flame area contributes to the fluctuation in heat release rate during a cycle of acoustic oscillations as characterized by the shear layer strength. The rolling of shear layers significantly enhance the mixing in diffusion flames in the same way as the flame stretch enhances the propagation speed in premixed flames.…”

Section: Non-premixed Flame Performancementioning

confidence: 99%

Combustion performance of eccentrically rotated flames

Ismael

Abdelkhalek

Kamal

2013

Proceedings of the Institution of Mechanical Engineers, Part A:

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Experimental/computational work highlighted the combustion performance with eccentric blockage rotation in the reactive flow passage to augment the turbulence production rates in the flame for acquiring high power to weight ratios and effective heat transfer in industrial applications. The temporal/spatial velocity gradients stimulated around the reactive stream boundaries enhanced the turbulence development in both premixed and non-premixed flames. The eccentric shapes included circular, elliptical, squared and triangular shafts as well as a triple/straight blade rotor. The design was further developed to incorporate simultaneous rotation of the eccentric blockage around its axis via a planetary gear assembly to duplicate the vortical structure. While the premixed flames responded to such cyclic action by having a mixture velocity of 16.8 m/s, the non-premixed flames acquired an increase of 341% in the largest eddy size and a flame length reduction by 42%. Increasing the Strouhal number to 0.94 and the swirl ratio to 0.78 increased the turbulent kinetic energy to 9.1 m 2 /s 2 . By controlling the drag coefficient and wake vorticity for the solid shapes, the triangular rotor enhanced the combustor outward heat flux to exhibit a heater efficiency of 36.8% in the premixed flame mode and reduced the HC and CO emissions, respectively, to 0.1% and 513 ppm for non-premixed flames. Decreasing the reactive stream cross-section favorably increased the flow shearing effects, while the elliptical shape showed the highest sensitivity to axes' orientation with respect to the direction of rotation. Due to the reduction in peak temperatures via increasing the turbulence intensity and heat transfer rate from the flame, the NO x exhaust concentrations decreased to a minimum value around 10 ppm. The combustion efficiency of diffusion flames was optimized with the fuel port central positioning in the burner, where the planetary gear design provided a turbulence intensity of 13.7% by the triple blade rotor.

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“…There have been many studies of nonlinear flame oscillations using acoustically excited flames. Kim et al [8] and Kartheekeyan et al [9] demonstrated that external forcing an induced flame periodic oscillation can further create undesirable nonlinear oscillations that affect the initial flow velocity and the mixing rate for a premixed flame. Experimental work has shown that flames exhibit nonlinear responses under various acoustic and combustion conditions.…”

Section: Introductionmentioning

confidence: 99%

Experimental observation of the nonlinear coupling of flame flow and acoustic wave

Chen

Zhang

2015

Flow Measurement and Instrumentation

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This is an experimental investigation to study the nonlinear coupling characteristics of a propane/air flame with acoustic standing waves, using chemiluminescence emission and phaselocked PIV measurements. A variety of coupling modes are observed for the excitation source with combustion instability oscillations and its harmonics and sub-harmonics. The frequency analysis shows that flame/acoustic coupling behaviour results in complex nonlinear coupling. The coupling behaviour is weak at lower excitation intensities (0.3V). At a voltage amplitude of 2 V, the results show that the excitation frequency (f e ) is only coupled with the sub-harmonic frequency (f e /5) for the premixed flame. However, for the diffusion flame, more complex frequency components are observed, which exhibit relationships of f e ± f f and f e ± f e /5. At a voltage amplitude of 13.7 V, the sub-harmonic frequencies (2f e /5 and 3f e /5) and the premixed flame buoyancy oscillations (f f ) are increased. PIV measurements provide detailed flow velocity vector fields in an acoustically excited tube for different phase angles and the effect on the flames at different equivalence ratios, which increases the understanding of flame oscillation behaviour. It is found that all of the nonlinear phenomena that are observed occur because of the coupling between buoyant and acoustic excitation and create complex nonlinear frequency couplings.

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An experimental investigation of an acoustically excited laminar premixed flame

Cited by 24 publications

References 37 publications

Dynamics and control of premixed combustion systems based on flame transfer and describing functions

Dynamics and control of premixed combustion systems based on flame transfer and describing functions

Combustion performance of eccentrically rotated flames

Experimental observation of the nonlinear coupling of flame flow and acoustic wave

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