Supersonic Combustion of Pylon-Injected Hydrogen in High-Enthalpy Flow with Imposed Vortex Dynamics

Vergine, Fabrizio; Crisanti, Matthew; Maddalena, Luca; Miller, Victor A.; Gamba, Mirko

doi:10.2514/1.b35330

Cited by 27 publications

(6 citation statements)

References 25 publications

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“…However, their limitations in flame-holding, fuel penetration and mixing characteristics are known in these applications; thus, other configurations that include various mixing-enhancement strategies have been considered (Gutmark, Schadow & Yu 1995;Seiner, Dash & Kenzakowski 2001) and continue to be developed. Some of the application-driven configurations are based on wall injection in the presence of a cavity (Donbar et al 2000;Rasmussen et al 2005;Rasmussen, Dhanuka & Driscoll 2007;Ryan et al 2009;Hsu et al 2010) or hyper-mixing configurations where vorticity-induced mixing is used to improve the overall performance and operability of supersonic combustors Gauba et al 1997;Doster et al 2009;Vergine et al 2015).…”

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confidence: 99%

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

Gamba

Mungal

2015

J. Fluid Mech.

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“…Recently, numerous fuel injector concepts have been proposed and investigated, especially for the cantilevered ramp injector located in the forebody/inlet of hypersonic vehicles [4][5] and pylon used as the vortex generator ahead of the orifice [6][7][8]. However, these devices are intrusive to the flow, generate drag, and require cooling [9].…”

Section: Introductionmentioning

confidence: 99%

“…The no-slip conditions (u = v = w = 0.0) are assumed for wall boundaries.The grid density is clustered towards the injection port for all grids and relaxed towards outlet, seeFig.2, andFig.2depicts the schematic diagram of the whole grid system employed in the current study. A boundary layer grid is generated on the walls with a first cell height of 0.001 mm, which results in a suitable value of y + for all6…”

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Mixing augmentation mechanism induced by the pseudo shock wave in transverse gaseous injection flow fields

Huang

Yan

2016

International Journal of Hydrogen Energy

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The mixing process between the injectant and air is very crucial for the engineering implementation of the scramjet engine, and this is due to the very short resident time of fuel in supersonic flows. In the current study, the three-dimensional Reynolds-average Navier-Stokes (RANS) equations coupled with the two equation k-ω shear stress transport (SST) turbulence model have been employed to investigate the transverse injection flow field with the pseudo shock wave induced by the high back pressure, and the freestream Mach number is 3.75. At the same time, the influence of the back pressure on the flow field properties has been evaluated as well. The obtained results show that the pseudo shock wave induced by the back pressure plays an important role in the mixing enhancement between the injectant and air. When the back pressure ratio is larger than 5.0, the mixing efficiency increases with the increase of the back pressure ratio. However, when the back pressure ratio is 3.0, the near-field mixing process has been improved, and accordingly its mixing efficiency in this region is larger than the benchmark. This implies that the intense combustion downstream of the injector can enhance the mixing process between the injectant and air, and the mixing and combustion process can be enhanced mutually. When the pseudo shock wave has been pushed upstream of the wall orifice, more injectant has been brought into the separation zone upstream of the injector, and this is beneficial for the mixing process between the

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“…These devices can provide an axial vortex which has been proved to be responsible for improving mixing in supersonic flows. Vergine et al (2015) studied the influences of the imposed interaction and subsequent dynamics of a system of selected supersonic streamwise vortices on the reacting plume morphology and its evolution. The hydrogen plume issued from two pylon-type injectors.…”

Section: Introductionmentioning

confidence: 99%

Supersonic mixing augmentation mechanism induced by a wall-mounted cavity configuration

Huang

Ding

et al. 2016

JZUS-A

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Abstract:An efficient mixing process is very important for the engineering implementation of an airbreathing propulsion system. The air and injectant should be mixed sufficiently before entering the combustor. Two new wall-mounted cavity configurations were proposed to enhance the mixing process in a conventional transverse injection flow field. Their flow field properties were compared with those of a system with only transverse injection ports. Grid independency analysis was used to choose a suitable grid scale, and the mixing efficiencies at four cross-sectional planes (namely x=20, 40, 60, and 80 mm, which are just downstream of the jet orifice) were compared for the configurations considered in this study. The results showed that hydrogen penetrated deeper when a cavity was mounted upstream of the transverse injection ports. This is beneficial to the mixing process in supersonic flows. The mixing efficiency of the configuration with the wall-mounted cavity was better than that of the conventional physical model, and the mixing efficiency of the proposed novel physical model I (98.71% at x=20 mm) was the highest of all. In the case with only transverse injection ports, the vortex was broken up by the strong interaction between the shear layer over the cavity and the jet.

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Supersonic Combustion of Pylon-Injected Hydrogen in High-Enthalpy Flow with Imposed Vortex Dynamics

Cited by 27 publications

References 25 publications

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

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

Mixing augmentation mechanism induced by the pseudo shock wave in transverse gaseous injection flow fields

Supersonic mixing augmentation mechanism induced by a wall-mounted cavity configuration

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