Flow-field dynamics of the non-reacting and reacting jet in a vitiated cross-flow

Pinchak, Matthew D.; Shaw, Vincent G.; Gutmark, Ephraim

doi:10.1016/j.proci.2018.07.019

Cited by 18 publications

(6 citation statements)

References 10 publications

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“…Hasselbrink & Mungal (2001) noted that the reacting methane transverse jets showed a reduction in entrainment and consequently a deeper penetration into the cross-flow. Pinchak, Shaw & Gutmark (2019) demonstrated that the wake dynamics and wake vortex behaviour significantly changed, resulting in a significantly larger wake structure in the reacting case. Considering the shear layer behaviour, Nair et al (2019) characterized the spatial growth rate for RJICF conditions showing that combustion suppresses the growth of the windward shear layer structures.…”

Section: Introductionmentioning

confidence: 99%

Combustion and flame position impacts on shear layer dynamics in a reacting jet in cross-flow

et al. 2022

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This study experimentally investigates reacting jets in cross-flow (RJICF), considering flame/shear layer offset, momentum flux ratio ( $J$ ) and density ratio ( $S$ ) effects. These results demonstrate that non-reacting JICF and RJICF can exhibit very similar or completely different dynamics and controlling physics, depending upon streamwise and radial flame location. Consistent with prior measurements of Getsinger et al. (Exp. Fluids, vol. 53 (3), 2012, pp. 783–801), spatial amplification rates of shear layer vortex (SLV) structures increased with decreasing $S$ for non-reacting cases. Similar $S$ dependencies exist for reacting cases in which the flame lay outside the jet shear layer, whose flow topology is also quite similar to non-reacting cases, albeit with reduced SLV growth rates. However, although the reacting cases have lower growth rates, these SLV structures ultimately reach approximately the same peak strength as in the non-reacting cases. Finally, the SLV decay rate in both non-reacting and reacting cases was found to similarly scale inversely with the initial SLV growth rate. As such, primarily inertial mechanisms govern SLV growth and decay for reacting cases where the flame lies outside the shear layer. In contrast, very different behaviour is exhibited by reacting cases where the flame lies inside the shear layer, where the locally increased viscosity exerts significant influences. In these reacting cases, SLV roll-up is completely suppressed and the entire jet column undulates over a long length scale relative to the jet diameter. As such, the relative roles of inertial and viscous mechanisms in controlling combustion influences on the SLV dynamics, changes markedly with shear layer–flame offset.

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Section: Introductionmentioning

confidence: 99%

Combustion and flame position impacts on shear layer dynamics in a reacting jet in cross-flow

et al. 2022

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“…The interplay between combustion and flow instabilities can lead to dangerous phenomena such as thermo-acoustic instabilities or blow-out 1,8,9 . For this reason, the flow instabilities produced by bluff-bodies and swirl have been extensively studied both theoretically [10][11][12] and experimentally [13][14][15] .…”

Section: Introductionmentioning

confidence: 99%

Multi-scale proper orthogonal decomposition analysis of instabilities in swirled and stratified flames

Procacci¹,

Kamal²,

Mendez

et al. 2022

Physics of Fluids

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This study examines the flow field dynamics of bluff-body stabilized swirling and non-swirling flames produced from the Cambridge/Sandia Stratified Swirl Burner. This burner has been used in previous studies as a benchmark for high-resolution scalar and velocity measurements and for validating numerical models. The burner was designed to create reacting flow conditions that are representative of turbulent flows in modern combustion systems, including sufficiently high turbulence levels, and to operate under both premixed and stratified conditions. High-speed stereoscopic Particle Image Velocimetry (PIV) was used to acquire time-resolved velocity data for a series of turbulent methane/air flames at both premixed and stratified conditions.We employ the Multi-Scale Proper Orthogonal Decomposition (mPOD) to identify the main flow patterns in the velocity field and isolate the coherent structures linked to various flow instabilities. The results show that the most energetic structures in the flow are consistent with the Bénard-von Kármán (BVK) instability due to the presence of the bluff-body and the Kelvin-Helmholtz (KH) instability caused by the shear layer between the inner and outer flow. In both the swirling and non-swirling cases, the BVK is suppressed by the combustion, except for the most stratified swirling case. Moreover, the results show that combustion does not affect the KH instability because the shear layer does not coincide with the flame position.

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“…Heat release in the reaction zone has been shown to impact the development and evolution of shear-layer vortices (Lyra et al. 2015; Pinchak, Shaw & Gutmark 2019; Nair et al. 2019 b ).…”

Section: Introductionmentioning

confidence: 99%

Frequency response analysis of a (non-)reactive jet in crossflow

Sayadi

Schmid

2021

J. Fluid Mech.

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Flow-field dynamics of the non-reacting and reacting jet in a vitiated cross-flow

Cited by 18 publications

References 10 publications

Combustion and flame position impacts on shear layer dynamics in a reacting jet in cross-flow

Combustion and flame position impacts on shear layer dynamics in a reacting jet in cross-flow

Multi-scale proper orthogonal decomposition analysis of instabilities in swirled and stratified flames

Frequency response analysis of a (non-)reactive jet in crossflow

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