The role of acoustics in flame/vortex interactions

Jackson, T. L.; Macaraeg, Michéle G.; Hussaini, M. Y.

doi:10.1017/s0022112093002265

Cited by 11 publications

(2 citation statements)

References 33 publications

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“…This is a direct indication of the increased turbulence and entraining effects by acoustics as attributed to the torroidal vortices (Vermeulen and Ramesh, 1998) and the decrease in mixing timescales relative to the flow timescales. Such a result agrees with the numerical results of Jackson et al (1993), who found that flame ignition is always enhanced at high frequencies. It also matches the results of Vermeulen and Yu (1987), who found the strength of the induced vortices approximately increases with frequency.…”

Section: Effect Of Strouhal Numbersupporting

confidence: 92%

Combustion Enhancement of a Gas Flare Using Acoustical Excitation

Behery

Mohamad

Kamal

2005

Combustion Science and Technology

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The effect of acoustical excitation on flame stability, trajectory, exhaust emissions, and gas temperatures from a gas flare stack in a crossflow was experimentally investigated. Circular, elliptical, and cup nozzle configurations were examined and compared with a sinusoidal wave excitation. It was found that increasing the pulsation amplitude enhances the combusting efficiency up to the quenching limit. Increasing the Strouhal number enhances the mixing with an optimum value at 0.25. With acoustical excitation, there was a reduction in the CO, unburned hydrocarbon (UHC), and NO x concentrations. It was found that the elliptical burner exhibits the widest stability range with respect to the pulsation strength, with the highest average CO concentration. The cup nozzle produced the least amounts of CO and UHC. Both nozzles revealed higher flame temperatures than those of the circular nozzle. There was an increase in flame temperatures with excitation, with the subsequent widening and reduction in flame length.

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Section: Effect Of Strouhal Numbersupporting

confidence: 92%

Combustion Enhancement of a Gas Flare Using Acoustical Excitation

Behery

Mohamad

Kamal

2005

Combustion Science and Technology

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“…The vorticity field generated by a single planar pressure wave moving through a cylindrical laminar flame was also examined in [74]. The shock-flame interaction creates vortices, and there has been significant work in flame-vortex-acoustic interactions (for a review, see [75]; for more recent work, see, for example, [76]). …”

Section: Theoretical and Numerical Studiesmentioning

confidence: 99%

Origins of the deflagration-to-detonation transition in gas-phase combustion

Oran

Gamezo

2007

Combustion and Flame

533

250

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Comparison of direct numerical simulations of turbulent flames using compressible or low‐Mach number formulations

Charentenay

Thévenin

Zamuner

2002

Numerical Methods in Fluids

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SUMMARYModelling turbulent ames with an acceptable accuracy remains an open problem. In order to progress in our understanding of turbulent combustion, direct numerical simulations have been extensively employed during the last decade. These direct simulations generally rely on a fully compressible formulation, leading to extremely small time-steps associated with the propagation of acoustic waves. But, for many practical applications, acoustic phenomena are not essential. Using an incompressible approach while taking into account a dilatation term should then be much more e cient in terms of computing time. In this article we want to investigate this point by comparing results of direct simulations relying either on the compressible equations or on the low-Mach number formulation. We employ in both cases detailed models to describe chemistry and transport, in order to obtain an accurate description of the reaction zones. Two test-cases are considered for the evaluation of the low-Mach number approximation. We ÿrst compute the evolution of homogeneous isotropic turbulence decaying with time, without chemical reactions. In the second case a turbulent premixed ozone ame is investigated. For both conÿgurations the computing time associated with the low-Mach number simulation is at least an order of magnitude shorter, while keeping a similar accuracy for the ame properties. This demonstrates that the low-Mach number formulation is extremely e cient and suitable to investigate the detailed structure of turbulent ames when acoustic phenomena are not of primary interest.

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The role of acoustics in flame/vortex interactions

Cited by 11 publications

References 33 publications

Combustion Enhancement of a Gas Flare Using Acoustical Excitation

Combustion Enhancement of a Gas Flare Using Acoustical Excitation

Origins of the deflagration-to-detonation transition in gas-phase combustion

Comparison of direct numerical simulations of turbulent flames using compressible or low‐Mach number formulations

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