Parametric Study of the Aftbody Design of an Airbreathing Hypersonic Accelerator

Ward, Alexander D. T.; Smart, Michael K.

doi:10.2514/1.a34983

Cited by 3 publications

(2 citation statements)

References 36 publications

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“…A high speed inlet is optimized by using gradient-based searches informed by an adjoint flow solution, the results show that an undesirable shock is removed in the optimized inlet compared with the original geometry [19]. A parametric numerical study of aftbody design of airbreathing high speed vehicle is conducted using three-dimensional Euler simulation, the results show that large variation in the thrust-to-drag ratio highlights the criticality of the aftbody [20]. Reardon et al [21] apply computational fluid dynamics method to study the unstart problem in variable-geometry inlet, it was found that the quasi-steady CFD was able to correctly predict the started or unstarted operating mode for the different cowl angles considered.…”

Section: Introductionmentioning

confidence: 99%

Numerical Investigation and Efficiency Analysis of Engine-Airframe Integration High speed Vehicle based on Fragment Computation

Chen,

Liu,

Zhang

et al. 2024

Preprint

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The performance analysis of the internal/external flows around a high speed vehicle in near-space is fundamental and critical to the configuration and structure design for high speed aircraft. In this paper, the two-dimensional coupled implicit Reynolds Average Navier-Stokes (RANS) solver and RNG k–ε turbulence model is employed to numerically simulate the flow field of an integrated high speed vehicle. The flow field are divided three parts to solve separately and compared with that solved by integrated simulation. The flow field are decomposed to save computer storage and simulation time. The first part is inlet/isolator, the second part is combustion chamber and the third is nozzle. In the computation process, the outlet condition of isolator is endowed to the inlet boundary of combustion chamber and the outlet boundary of combustion chamber is endowed to the inlet boundary of nozzle, then the whole flow field of integrated high speed vehicle is solved. Aerodynamic characteristic of fragment-computation and integration-computation is comparatively analyzed at different angles of attack, the results show that the maximum deviation of lift coefficient obtained by fragment-computation is less than 3% compared with that by integration, the maximum deviation of drag coefficient fragment-computation is less than 5% compared with that by integration, while pitching moment coefficient deviation less than 12%. However, for simulation time-consumption, the time used by fragment-computation reduces 45% compared with integration-computation. Meanwhile, by components force analysis, it can be concluded that the aerodynamic property of inlet/isolator can been obtained separately and hardly effected by other parts.

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Section: Introductionmentioning

confidence: 99%

Numerical Investigation and Efficiency Analysis of Engine-Airframe Integration High speed Vehicle based on Fragment Computation

Chen,

Liu,

Zhang

et al. 2024

Preprint

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show abstract

“…Shock impingement and large associated changes in local flow-field properties are prevalent for hypersonic flight vehicles (Heiser & Pratt 1994;Ward & Smart 2021). While an uncontrolled flow separation results in an engine unstart (Im & Do 2018) and energy losses, shock impingement in internal flow configurations also initiates combustion (Laurence et al 2013;Landsberg et al 2018;Curran, Wheatley & Smart 2019) and flame-holding (Chang et al 2016(Chang et al , 2018Landsberg et al 2020a,b;Vanyai et al 2021).…”

Section: Introductionmentioning

confidence: 99%

Hypersonic shock impingement studies on a flat plate: flow separation of laminar boundary layers

et al. 2022

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Interactions between shock waves and boundary layers produce flow separations and augmented pressure/thermal loads in hypersonic flight. This study provides details of Mach 7 impinging-shock-flat-plate experiments conducted in the T4 Stalker Tube. Measurements were taken at flow conditions of Mach 7.0 (2.44 MJ kg $^{-1}$ ) and Mach 7.7 (2.88 MJ kg $^{-1}$ ) flight enthalpies with a range of freestream unit Reynolds numbers from $1.43 \times 10^{6}$ m $^{-1}$ to $5.01 \times 10^{6}$ m $^{-1}$ . A shock generator at $12^{\circ }$ or $16^{\circ }$ to the freestream created an oblique shock which impinged on a boundary layer over a flat plate to induce flow separation. The flow field was examined using simultaneous measurements of wall static pressure, heat transfer and schlieren visualisation. Measured heat transfer along the flat plate without the shock impingement indicated that the boundary layer remained laminar for all flow conditions. The shock impingement flow field was successfully established within the facility test duration. The onset of separation was observed by a rise in wall pressure and a decrease in heat transfer at the location corresponding to the stem of the separation shock. Downstream of this initial rise, an increased pressure and higher heating loads were observed. The heat-transfer levels also indicated an immediate boundary layer transition due to the shock impingement. The separation data of the present work showed good agreement with our previous work on shock impingement on heated walls (Chang et al., J. Fluid Mech., vol. 908, 2021, pp. 1–13). A comparison with the previous scaling indicated that the separation also relates to the pressure ratio and the wall temperature parameter.

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Maximizing Lift-to-Drag and Thrust-to-Drag Ratios for Trimmed Hypersonic Vehicles

Mbagwu

Dalle

Driscoll

2023

Journal of Aircraft

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Ways to maximize the lift-to-drag ([Formula: see text]) and the thrust-to-drag ([Formula: see text]) ratios of hypersonic vehicles are computed using the reduced-order model Michigan-AFRL Scramjet in Vehicle (MASIV). The 84 geometries considered are variations of a generic X-43 for seven chord lengths and three span lengths of the two horizontal stabilizers, and four engine widths. For all cases the vehicle is trimmed for cruise at Mach 8. Computed for each geometry were [Formula: see text], angle of attack, deflection angle of the horizontal stabilizer, specific impulse, and engine equivalence ratio. It was found that the “lifting body” design (with small horizontal stabilizers) has a larger [Formula: see text] than a wing–body design. Large horizontal stabilizers may not be desirable at hypersonic speeds because, while they reduce the angle of attack and reduce the wave drag, the added length of leading edges increases viscous drag. In addition, the optimum acceleration history was computed that minimizes the fuel required for an ascent, for different geometries. Selecting a large dynamic pressure trajectory was found to significantly minimize the fuel required. The scope of the work is limited to aerodynamics, and it does not consider either vehicle stability or control.

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Parametric Study of the Aftbody Design of an Airbreathing Hypersonic Accelerator

Cited by 3 publications

References 36 publications

Numerical Investigation and Efficiency Analysis of Engine-Airframe Integration High speed Vehicle based on Fragment Computation

Numerical Investigation and Efficiency Analysis of Engine-Airframe Integration High speed Vehicle based on Fragment Computation

Hypersonic shock impingement studies on a flat plate: flow separation of laminar boundary layers

Maximizing Lift-to-Drag and Thrust-to-Drag Ratios for Trimmed Hypersonic Vehicles

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