Time-resolved study of mixing and reaction in an aero-engine model combustor at increased pressure

Litvinov, Ivan V.; Yoon, Jong-Kyu; Noren, Carrie A.; Stöhr, Michael; Boxx, Isaac; Geigle, Klaus Peter

doi:10.1016/j.combustflame.2021.111474

Cited by 24 publications

(17 citation statements)

References 49 publications

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“…This diagnostic system has been described previously in the scientific literature (Litvinov et al. 2021). For completeness, a brief description is included below.…”

Section: Experimental Methodsmentioning

confidence: 99%

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Impact of precessing vortex core dynamics on the thermoacoustic instabilities in a swirl-stabilized combustor

et al. 2022

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Global instabilities in swirling flows can significantly alter the flame and flow dynamics of swirl-stabilized flames, such as those in modern gas turbine engines. In this study, we characterize the interaction between the precessing vortex core (PVC), which is the consequence of a global hydrodynamic instability, and thermoacoustic instabilities, which are the result of a coupling between combustor acoustics and the unsteady heat release rate. This study is performed using experimental data obtained from a model gas turbine combustor employing two concentric swirling nozzles of air, separated by a ring of fuel injectors, operating at five bar pressure. The flow split between the two streams is systematically varied to observe the impact of flow structure variation on the system dynamics at both non-reacting and reacting conditions. High-speed stereoscopic particle image velocimetry, OH planar laser-induced fluorescence and acetone planar laser-induced fluorescence are used to obtain information about the velocity fields, flame and fuel flow behaviour, respectively. Spectral proper orthogonal decomposition and a complex network analysis are used to identify and characterize the dominant oscillation mechanisms driving the system. In the non-reacting data, a PVC is present in most cases and the amplitude of the oscillation increases with increasing flow through the centre nozzle. In the reacting data, three dominant modes are seen: two thermoacoustic modes and the PVC. Our results show that in the cases where the frequency of the PVC overlaps with either of the thermoacoustic modes, the thermoacoustic modes are suppressed. The complex network analysis coupled with a weakly nonlinear theoretical analysis suggests the mechanisms by which this coupling and suppression of the thermoacoustic mode occur.

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“…This diagnostic system has been described previously in the scientific literature (Litvinov et al. 2021). For completeness, a brief description is included below.…”

Section: Experimental Methodsmentioning

confidence: 99%

“…Data were obtained for 1 s in the technically premixed ethylene/air swirl flame stabilized in the model of the aero-engine combustor. This diagnostic system has been described previously in the scientific literature (Litvinov et al 2021). For completeness, a brief description is included below.…”

Section: Measurement Techniquesmentioning

confidence: 99%

Impact of precessing vortex core dynamics on the thermoacoustic instabilities in a swirl-stabilized combustor

et al. 2022

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“…Run duration was 1 s in the technically premixed ethylene/air swirl flame stabilized in the model of the aero-engine combustor. This diagnostic system has been described previously in the scientific literature (Litvinov et al 2021). For completeness, a brief description is included below.…”

Section: Measurement Techniquesmentioning

confidence: 99%

Impact of precessing vortex core dynamics on the thermoacoustic instabilities in a swirl stabilized combustor

Karmarkar¹,

Gupta²,

Boxx³

et al. 2020

Preprint

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Global instabilities in swirling flows can significantly alter the flame and flow dynamics of swirlstabilized flames, such as those in modern power generation gas turbine engines. In this study, we characterize the interaction between the precessing vortex core (PVC), which is the consequence of a global hydrodynamic instability, and thermoacoustic instabilities, which are the result of a resonant coupling between combustor acoustics and the unsteady heat release rate of combustion. This characterization is performed using experimental data obtained from a model gas turbine combustor system employing two concentric swirling nozzles of air, separated by a ring of fuel injectors, operating at 5 bar pressure. The flow split between the two streams is systematically varied to observe the impact of flow structure variation on the flow and flame dynamics. High-speed stereoscopic particle image velocimetry, OH planar laser-induced fluorescence, and acetone planar laser-induced fluorescence are used to obtain information about the velocity fields, flame, and fuel flow behavior, respectively. Spectral proper orthogonal decomposition and spatial frequency analysis are used to identify and characterize the dominant oscillation mechanisms driving the system. Three dominant modes are seen: two thermoacoustic modes and the precessing vortex core. Our results show that in the cases where the frequency of the PVC overlaps with either of the thermoacoustic modes, the thermoacoustic modes are suppressed. A weakly nonlinear asymptotic analysis shows that the suppression of the axisymmetric shear layer shedding, and hence thermoacoustic mode, is the result of a nonlinear coupling between the PVC and the axisymmetric mode of the swirling jet. Evolution equations for both the symmetric and PVC modes are derived to show the controlling parameters that drive this suppression. We conclude by discussing ways in which thermoacoustic instability suppression can be achieved through combustor flow field design.

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“…Mixing is crucial to many process scale-up projects. [1][2][3][4] It affects a diverse range of chemically-intensive processes such as phase-transfer catalysis, [5][6][7][8] additive manufacturing, [9][10][11] fuel combustion, 12 flow chemistry, 13 powder formulation, 14,15 biotechnology, 16 and (most pertinent to this paper) myriad reaction scale-ups in tank reactors. [16][17][18][19][20] Mixing represents one of the most effective, non-chemical means of process improvement.…”

Section: Impact Of Mixingmentioning

confidence: 99%

Computer Vision for Kinetic Analysis of Lab- and Process-scale Mixing Phenomena

Barrington,

Dickinson,

McGuire

et al. 2022

Preprint

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A software platform for the computer vision-enabled analysis of mixing phenomena of relevance to process scale-up is described. By bringing new and known time-resolved mixing metrics under one platform, hitherto unavailable comparisons of pixel-derived mixing metrics are exemplified across non-chemical and chemical processes. The analytical methods described are applicable using any camera and across an appreciable range of reactor scales, from development through to process scale-up. A case study in nucleophilic aromatic substitution run on 5L-scale shows how camera and offline concentration measurements can be correlated. In some cases, it can be shown that camera data holds the power to predict reaction progress.

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Time-resolved study of mixing and reaction in an aero-engine model combustor at increased pressure

Cited by 24 publications

References 49 publications

Impact of precessing vortex core dynamics on the thermoacoustic instabilities in a swirl-stabilized combustor

Impact of precessing vortex core dynamics on the thermoacoustic instabilities in a swirl-stabilized combustor

Impact of precessing vortex core dynamics on the thermoacoustic instabilities in a swirl stabilized combustor

Computer Vision for Kinetic Analysis of Lab- and Process-scale Mixing Phenomena

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