Premixed swirling flame stabilization

A diffusion swirling flame under external forcing and self-excitation within a single swirler combustor have been studied in this paper with the large-eddy simulation and linear acoustic method. The combustor features pre-vaporized kerosene as the fuel, a single radial air swirler for flame stabilization and a square cross section chamber with adjustable length. Firstly, self-sustained pressure oscillation has been achieved by using of a chocked nozzle on the chamber outlet with large-eddy simulation. Dynamic pressure oscillations are analyzed in frequency domain through Fast Fourier Transform. The major pressure oscillation is identified as the 1st order longitudinal mode of the chamber. Further, the same frequency in the form of harmonic velocity oscillation is imposed on the inlet of the combustor while the chamber length has been changed. Based on this approach, a comparative study of the flame response with different excitation method but same frequency is carried out. In both self-excited and forced cases, global and local flame responses as well as Rayleigh index have been analyzed and compared. With the flame response function, the excited acoustic modes under the influence of dynamic heat release have been predicted with linear acoustic method and compared with the results obtained from large-eddy simulation. Results show that the flame response presents a great difference in the spacial distribution with different excitation approaches. Thermo-acoustic interaction distributes along the flame front with the expansion of the flame under self-excitation while it damps with the acoustic propagating downstream under forcing condition. As the ratio of flame length to acoustic wave length could not be neglected for the diffusion swirling flame, the global flame response under forcing cannot represent the local response feature of the flame accurately, thus influencing the instability prediction.

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Large Eddy Simulation of a Pressurized, Partially Premixed Swirling Flame With Finite-Rate Chemistry

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.4040007 ◽

2018 ◽

Vol 140 (11) ◽

Cited By ~ 1

Author(s):

Sandeep Jella ◽

Pierre Gauthier ◽

Gilles Bourque ◽

Jeffrey Bergthorson ◽

Ghenadie Bulat ◽

...

Keyword(s):

Gas Turbine ◽

Flame Stabilization ◽

Navier Stokes ◽

No Production ◽

Gas Turbine Combustor ◽

Finite Rate ◽

Local Flow ◽

Eddy Simulation ◽

Large Eddy ◽

Swirling Flame

Finite-rate chemical effects at gas turbine conditions lead to incomplete combustion and well-known emissions issues. Although a thin flame front is preserved on an average, the instantaneous flame location can vary in thickness and location due to heat losses or imperfect mixing. Postflame phenomena (slow CO oxidation or thermal NO production) can be expected to be significantly influenced by turbulent eddy structures. Since typical gas turbine combustor calculations require insight into flame stabilization as well as pollutant formation, combustion models are required to be sensitive to the instantaneous and local flow conditions. Unfortunately, few models that adequately describe turbulence–chemistry interactions are tractable in the industrial context. A widely used model capable of employing finite-rate chemistry is the eddy dissipation concept (EDC) model of Magnussen. Its application in large eddy simulations (LES) is problematic mainly due to a strong sensitivity to the model constants, which were based on an isotropic cascade analysis in the Reynolds-averaged Navier–Stokes (RANS) context. The objectives of this paper are: (i) to formulate the EDC cascade idea in the context of LES; and (ii) to validate the model using experimental data consisting of velocity (particle image velocimetry (PIV) measurements) and major species (1D Raman measurements), at four axial locations in the near-burner region of a Siemens SGT-100 industrial gas turbine combustor.

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EXPERIMENTAL STUDY OF A LEAN PREMIXED TURBULENT SWIRLING FLAME STABILIZATION

10.26678/abcm.cobem2017.cob17-0808 ◽

2017 ◽

Cited By ~ 1

Author(s):

Luís Fernando Figueira da Silva ◽

Carolina Mergulhão ◽

Letícia Piton ◽

scouflaire philippe ◽

Nasser Darabiha

Keyword(s):

Experimental Study ◽

Flame Stabilization ◽

Lean Premixed ◽

Swirling Flame

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Large Eddy Simulations of a Pressurized, Partially-Premixed Swirling Flame With Finite-Rate Chemistry

Volume 4B: Combustion, Fuels and Emissions ◽

10.1115/gt2017-65256 ◽

2017 ◽

Author(s):

Sandeep Jella ◽

Pierre Gauthier ◽

Gilles Bourque ◽

Jeffrey Bergthorson ◽

Ghenadie Bulat ◽

...

Keyword(s):

Gas Turbine ◽

Flame Stabilization ◽

Large Eddy Simulations ◽

No Production ◽

Gas Turbine Combustor ◽

Finite Rate ◽

Local Flow ◽

Large Eddy ◽

Swirling Flame ◽

Eddy Structures

Finite-rate chemical effects at gas turbine conditions lead to incomplete combustion and well-known emissions issues. Although a thin flame front is preserved on an average, the instantaneous flame location can vary in thickness and location due to heat losses or imperfect mixing. Post-flame phenomena (slow CO oxidation or thermal NO production) can be expected to be significantly influenced by turbulent eddy structures. Since typical gas turbine combustor calculations require insight into flame stabilization as well as pollutant formation, combustion models are required to be sensitive to the instantaneous and local flow conditions. Unfortunately, few models that adequately describe turbulence-chemistry interactions are tractable in the industrial context. A widely used model capable of employing finite-rate chemistry, is the Eddy Dissipation Concept (EDC) model of Magnussen. Its application in large eddy simulations (LES) is problematic mainly due to a strong sensitivity to the model constants which were based on an isotropic cascade analysis in the RANS context. The objectives of this paper are: (i) To formulate the EDC cascade idea in the context of LES; and (ii) To validate the model using experimental data consisting of velocity (PIV measurements) and major species (1-D Raman measurements), at four axial locations in the near-burner region of a Siemens SGT-100 industrial gas turbine combustor.

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Modeling of Turbulent Swirling Flame Stabilization in LPP Combustors

Volume 3: Coal, Biomass and Alternative Fuels; Combustion and Fuels; Oil and Gas Applications; Cycle Innovations ◽

10.1115/98-gt-493 ◽

1998 ◽

Author(s):

A. Smirnov ◽

A. Lipatnikov ◽

J. Chomiak

Keyword(s):

Heat Release ◽

Flame Spread ◽

Computing Time ◽

Turbulent Flame ◽

Flame Stabilization ◽

Closure Model ◽

Reactor Model ◽

Flow Recirculation ◽

Turbulent Flame Speed ◽

Swirling Flame

Combustion flows with swirl are investigated in the context of a lean premixed pre-vaporized combustor. The turbulent flame speed closure model implemented into the Kiva program appears to be efficient in utilizing computing time and memory. It also predicts a larger flame spread than a distributed reactor model. The effect of different turbulence and combustion models on flow recirculation patterns and heat release is reported.

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