An Overview of the HIFiRE Flight 2 Project (Invited)

Jackson, Kevin; Gruber, Mark; Buccellato, Salvatore

doi:10.2514/6.2013-695

Cited by 7 publications

(2 citation statements)

References 14 publications

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“…Among the experimental configurations available in the literature [7][8][9][10][11], that of AFRL is chosen because a large number of experiments have been carried out with this device over the years.…”

Section: Configuration Descriptionmentioning

confidence: 99%

Analysis of combustion modes in a cavity based scramjet

Ruan

Domingo

Ribert

2020

Combustion and Flame

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Large eddy simulations (LES) of non reactive and reactive flows in a cavity-based scramjet combustor configuration from the U.S Air Force Research Laboratory (AFRL) are performed. These simulations feature a 22 species and 206 reactions chemical scheme for ethylene/air. The ability of LES to reproduce the main features found in the experiment is first emphasised such as the average velocity field and the stability of the combustion for the case studied. The influence of the mesh resolution and of the thermal wall condition on the simulation results is also investigated along with the soundness of the use of a laminar model for the filtered source terms. The results of the simulations with the finest grid (resolution of 100 micrometers in the flame region) are then employed to gain understanding in the flame dynamics. This reactive simulation shows the persistence of the two recirculation zones already present in the non reactive flow. The globally high temperature into the cavity helps to sustain a reactive zone located in the mixing layer above the cavity. Combustion first occurs in a diffusion dominated regime followed by the efficient burning of a well stirred mixture (rich then lean). A significant diffusion dominated burning is also found inside the cavity. The links between the residence time inside the cavity and the efficiency of the combustion are explored along with the velocity/heat release correlation.

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Section: Configuration Descriptionmentioning

confidence: 99%

Analysis of combustion modes in a cavity based scramjet

Ruan

Domingo

Ribert

2020

Combustion and Flame

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“…These limitations have restricted the Mach number regime of flight tests, with the corresponding computational studies typically analysing mid-range Mach number (5 ≤ M < 10) scramjets. These have included the Mach 5 X-51A [4], the Mach 7 X-43A [5] and the Mach 8 HyShot II [6] and HIFiRE 2 [7] experiments. While a small subset of ground-based studies examined high Mach number (M ≥ 10) scramjets [8,9], limited flight data exists for these engines.…”

Section: Introductionmentioning

confidence: 99%

Performance of high mach number scramjets - Tunnel vs flight

et al. 2018

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While typically analysed through ground-based impulse facilities, scramjets experience significant heating loads in flight, raising engine wall temperatures and the fuel used to cool them beyond standard laboratory conditions. Hence, the present work numerically compares an access-to-space scramjet's performance at both these conditions. The Mach 12 Rectangular-to-Elliptical Shape-Transitioning scramjet flow path is examined via three-dimensional and chemically reacting Reynolds-averaged Navier-Stokes solutions. Flight operation is modelled through 800 K and 1800 K inlet and combustor walls respectively, while fuel is injected at both inlet-and combustor-based stations at 1000 K stagnation temperature. Room temperature walls and fuel plena model shock tunnel conditions. Mixing and combustion performance indicates that while flight conditions promote rapid mixing, high combustor temperatures inhibit the completion of reaction pathways, with reactant dissociation reducing chemical heat release by 16%. However, the heated walls in flight ensured 28% less energy was absorbed by the walls. While inlet fuel injection promotes robust burning of combustor-injected fuel, premature ignition upon the inlet in flight suggests these injectors should be moved further downstream. Coupled with counteracting differences in heat release and loss to the walls, the optimal engine design for flight may differ considerably from that which gives the best performance in the tunnel.

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