Time-Averaged Characteristics of a Reacting Fuel Jet in Vitiated Cross-Flow

Sullivan, R. C.; Wilde, Benjamin; Noble, David R.; Seitzman, Jerry M.; Lieuwen, Tim

doi:10.2514/6.2012-3761

Cited by 11 publications

(17 citation statements)

References 38 publications

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“…The second stage fuel is injected into the vitiated hot-gas flowing from the first stage, leading to a reaction zone stabilised by mixture autoignition and flame propagation. One can refer to previous numerical studies [19,29,27] and experimental work [27,25,1]. The thermoacoustic stability is one of the main challenges in gas turbine combustor engineering, especially in lean conditions [14].…”

Section: Introductionmentioning

confidence: 99%

Autoignition flame dynamics in sequential combustors

Schulz

Noiray

2018

Combustion and Flame

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This numerical study deals with the heat release rate response of a sequential combustor flame to temperature perturbations. These flames are found in the new generation of gas turbine combustors, which are based on sequential combustion technologies. It is shown that the temperature perturbations T upstream of the fuel injection induce mixture fraction oscillations Z which also propagate toward the reaction zone, and that the combination of these two perturbations yields a strongly nonlinear heat release rate response Q . Large Eddy Simulation (LES) were performed using an Analytically Reduced Chemistry (ARC) mechanism, which includes 22 transported species in combination with the Dynamic Thickened Flame model (DTF). The burner flame transfer function (BFTF) giving the flame response with respect to T is obtained using a broadbandexcitation-based system identification (SI) as well as harmonic single frequency excitations. A simplified configuration with perfectly premixed conditions is considered to quantify the respective contributions of the different types of perturbation. These simulations highlight (i) the strong nonlinearity of the flame response to temperature perturbations, and (ii) the difficulty to break down the global flame response into independent driving mechanisms by making use of "simplified" configurations.

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Section: Introductionmentioning

confidence: 99%

Autoignition flame dynamics in sequential combustors

Schulz

Noiray

2018

Combustion and Flame

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“…More recently, work has also been directed at investigating the reacting characteristics of more complex fuel injection approaches that can be found in scramjet applications (Donbar et al 2000;Rasmussen et al 2007;Ryan et al 2009). More recently, reacting transverse jets in subsonic crossflow have also found renewed interest (Huang & Chang 1994;Grout et al 2011;Kolla et al 2012;Micka & Driscoll 2012;Schaupp, Friedrich & Foysi 2012;Sullivan et al 2014). …”

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confidence: 96%

Ignition, flame structure and near-wall burning in transverse hydrogen jets in supersonic crossflow

Gamba

Mungal

2015

J. Fluid Mech.

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We have investigated the properties of transverse sonic hydrogen jets in hightemperature supersonic crossflow at jet-to-crossflow momentum flux ratios J between 0.3 and 5.0. The crossflow was held fixed at a Mach number of 2.4, 1400 K and 40 kPa. Schlieren and OH * chemiluminescence imaging were used to investigate the global flame structure, penetration and ignition points; OH planar laser-induced fluorescence imaging over several planes was used to investigate the instantaneous reaction zone. It is found that J indirectly controls many of the combustion processes. Two regimes for low (<1) and high (>3) J are identified. At low J, the flame is lifted and stabilizes in the wake close to the wall possibly by autoignition after some partial premixing occurs; most of the heat release occurs at the wall in regions where OH occurs over broad regions. At high J, the flame is anchored at the upstream recirculation region and remains attached to the wall within the boundary layer where OH remains distributed over broad regions; a strong reacting shear layer exists where the flame is organized in thin layers. Stabilization occurs in the upstream recirculation region that forms as a consequence of the strong interaction between the bow shock, the jet and the boundary layer. In general, this interaction -which indirectly depends on J because it controls the jet penetration -dominates the fluid dynamic processes and thus stabilization. As a result, the flow field may be characterized by a flame structure characteristic of multiple interacting combustion regimes, from (non-premixed) flamelets to (partially premixed) distributed reaction zones, thus requiring a description based on a multi-regime combustion formulation.

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“…For applications such as secondary injection of fuel into a vitiated gas stream in a gas turbine combustor, rapid mixing and chemical reaction in the near-field of jet injection plane are desirable. In a recent study based on high-speed CH* and OH* chemiluminescence imaging, vitiated crossflow, it was 6 observed that the flame stabilizes just downstream of the injector [23] [24]. The H2/CO jet flames remained attached to the injector for all observed conditions.…”

Section: Equationmentioning

confidence: 83%

“…The orange arrow indicates the direction of the crossflow. The wake structure is a vorticity iso-surface of ±5000 s -1 23…”

Section: Velocity Fieldmentioning

confidence: 99%

High-repetition-rate planar measurements in the wake of a reacting jet injected into a swirling vitiated crossflow

Panda¹,

Roa

Slabaugh³

et al. 2016

Combustion and Flame

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Staged combustion has been explored for power generation gas turbine engines to increase engine efficiency with minimal contribution to pollutant formation. Secondary fuel injection into the vitiated flow from the primary combustion process is one approach. In this work, advanced diagnostic measurements were performed on an experimental representation of such a system, with a transverse jet injection into a swirling vitiated crossflow.High-repetition-rate simultaneous particle image velocimetry (PIV) and OH planar laser-induced fluorescence (PLIF) were performed at three measurement planes perpendicular to the jet axis. The measurements provided qualitative as well as quantitative information on the evolution of complex flow structures and transient events such as re-ignition, local extinction and vortex-flame interactions in the turbulent reacting flow. Transverse jets composed of H 2 mixed with N 2 and premixed natural gas and air were injected through a tube protruding into the crossflow. The vitiated crossflow is produced by a low swirl burner (LSB). The crossflow exhibits considerable swirl at the location of the transverse jet injection. Two momentum flux ratios, J=3 and J=8 were employed to study the effect of momentum flux ratio on the stabilization of reaction fronts. The time-averaged flow field show a pair of steady wake vortices, which were found to be much larger for J = 8 than for the J=3 case. The region with the maximum time-averaged OH-PLIF intensity was found to be localized between the wake vortex pairs. The wake Strouhal number was found to be invariant with respect to the momentum flux ratio. Based on the experimental data, it is hypothesized that the shear layer and wake field vortices play a significant role in stabilizing a steady reaction front within the near-wake region of the jet.

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Time-Averaged Characteristics of a Reacting Fuel Jet in Vitiated Cross-Flow

Cited by 11 publications

References 38 publications

Autoignition flame dynamics in sequential combustors

Autoignition flame dynamics in sequential combustors

Ignition, flame structure and near-wall burning in transverse hydrogen jets in supersonic crossflow

High-repetition-rate planar measurements in the wake of a reacting jet injected into a swirling vitiated crossflow

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