Flow Physics Inside a Shape-Transitioning Scramjet Engine

Barth, James E.; Wheatley, Vincent; Smart, Michael K.; Petty, David; Basore, Kevin

doi:10.2514/6.2012-5888

Cited by 7 publications

(18 citation statements)

References 14 publications

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“…6 Additional benefits of this inlet are good performance at off-design conditions, making it suitable as a stage in future access-to-space missions. 8 Barth et al 8 present a complete investigation of the flowfield within the REST engine at Mach 12 flight conditions, with an inlet Mach number of 9.3, suggesting that higher mixing efficiency could be obtained by taking advantage of the vortical structures generated by the REST inlet geometry. …”

Section: Iib Rectangular-to-elliptical Shape Transition (Rest) Inletmentioning

confidence: 99%

“…The flow conditions for the current study have been selected to match a MACH 12 scramjet flight condition on a 50 kPa constant dynamic pressure trajectory, 8 which has previously been used for ground testing at the university of Queensland. After accounting for a 6 • angle of attack forebody compression, the flow conditions into the inlet (Inlet) and in the vicinity of an inlet ramp injector (Inj.reg.)…”

Section: Iiia Flow Conditionsmentioning

confidence: 99%

See 1 more Smart Citation

Effect of Streamwise Vortices on Scramjets Porthole Injection Mixing

Gómez¹,

Jahn²,

Gollan³

2015

20th AIAA International Space Planes and Hypersonic Systems and Technologies Conference

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The use of Scramjets for space access could lead to important reductions in cost for satellite placement in Low Earth Orbit (LEO) and Sun-synchronous Orbit (SSO). The design of a fully operating Scramjet has proven extremely challenging, due to different issues. One of these is efficient fuel-air mixing, a prerequisite for efficent fuel combustion within the short air residence time during supersonic combustion. It has been suggested that streamwise vortices, either naturally generated by the Scramjet intake geometry, or artificially generated by vortex generators, could be used to enhance the mixing rate of fuel in air. This work presents a numerical study of the interaction between the fuel plume of a porthole injector and streamwise vortices, with focus on the effect on mixing. Flow conditions representative of a Mach 12 flight and equivalent ground-based Scramjet test conditions are investigated. The results show a significant enhancement in fuel penetration and mixing.This numerical investigation quantifies the increase in mixing efficiency that can be attained in a canonical geometry by tailoring the fuel jet location to exploit naturally occurring streamwise vortices. Three different vortex intensities, two different injector locations and two different injection to free stream momentum ratios are investigated. The relevant mechanisms driving the mixing enhancement and the best injector location are identified.

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Section: Iib Rectangular-to-elliptical Shape Transition (Rest) Inletmentioning

confidence: 99%

Section: Iiia Flow Conditionsmentioning

confidence: 99%

Effect of Streamwise Vortices on Scramjets Porthole Injection Mixing

Gómez¹,

Jahn²,

Gollan³

2015

20th AIAA International Space Planes and Hypersonic Systems and Technologies Conference

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“…In order to obtain data relevant to real scramjet operation, the flow conditions represent those found in the MACH 12 REST engine 14,15) tested at a 50 kPa constant dynamic pressure trajectory operating condition. 16) Barth et al 16) presented a complete investigation of the flowfield, from which the values of velocity (U), dynamic pressure (q), and total enthalpy (H 0 ) summarized in Table1 have been extracted. The US3D code developed at the University of Minnesota 17) is used as the CFD solver.…”

Section: Computational Approachmentioning

confidence: 99%

Effect of Vortex-injection Interaction on Wall Heat Transfer in a Flat Plate with Fin Corner Geometry

Llobet

Gollan

Jahn

2017

AEROSPACE TECHNOLOGY JAPAN

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More flexible and economical access to space is achievable using hypersonic air-breathing propulsion. One of the main challenges for hypersonic air-breathing propulsion is reaching high combustion efficiency within the short residence time of the flow in the engine. Lengthening the combustor is not a viable option due to its many drawbacks, and the use of hypermixers or strut injectors increases mixing efficiency at the cost of increasing losses and heat load. On the contrary, inlet-generated vortices are an intrinsic feature of many scramjet inlets, and can be used to enhance mixing, incurring minimal losses and heat load increase. A previous computational study used a canonical geometry consisting of a flat plate with a fin at different deflection angles to investigate the ability of inlet-generated vortices to enhance the mixing rate. Significant increases in mixing rate were obtained due to the vortex-fuel plume interaction. The flow conditions were equivalent to those found in a rectangular-to-elliptical shape transition scramjet inlet at a Mach 12, 50 kPa constant dynamic pressure trajectory. Despite the minimal heat load increase of this approach, characterization of the vortex-fuel plume interaction effect on the wall heat transfer is required. In this work, the previous study is extended, describing the effect of the vortex-fuel plume interaction on wall heat transfer. Heat flux in the vicinity of the porthole injector reaches 200 % compared to the baseline case with no vortex interaction. Moreover, the injection bow shock affects the corner region, creating pockets of heat flux up to 75 % larger than the unaffected region. Additionally, the evolution of the fuel plume downstream of the injector location is investigated, describing the relationship between local maxima and minima of heat flux, and the location of the fuel on the wall surface. This relationship can be exploited in experimental data acquisition to obtain the fuel location from heat flux data. The viability of this experimental approach is explored using computational data, confirming that through careful sensor placement, position measurements with an accuracy higher than ±5 mm can be achieved.

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“…This is a consequence of the slightly different freestream Mach number and unit Reynolds number of the two test conditions. Further discussion of the internal flow field of a rest engine, with particular focus on the inlet, may be found in Barth et al (2012) and Turner (2010).…”

Section: Internal Flow Fieldmentioning

confidence: 99%

“…The corresponding reduction in total inlet drag and net engine drag would be 13 % and 5 %, respectively. Injection of fuel within the isolator of the m12rest engine is currently under investigation (Barth et al, 2012, Section III.C), albeit with the goal of more effectively delivering fuel into the mainstream flow of the engine. Based on the data presented in Figure 5.11a, the results of Mitani et al (1999), Tanimizu et al (2009), andTurner (2010) and the preceding discussion, it is recommended here that some research effort be focussed on reducing inlet viscous drag, with particular emphasis on the suitability and performance of multiporthole injector arrays, similar to that studied by Pudsey et al (2013).…”

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confidence: 99%

An experimental investigation of an airframe integrated three-dimensional scramjet engine at a Mach 10 flight condition

Doherty¹

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The University of Queensland in 2014 school of mechanical and mining engineering centre for hypersonics abstract Realisation of the dream of airbreathing access-to-space requires the development of a scramjet engine that produces sufficient net thrust to enable acceleration over a wide Mach number range. With engines that are highly integrated with the airframe, the net performance of a scramjet powered vehicle is closely coupled with the vehicle attitude and is difficult to determine only from component level studies. This work investigates the influence of airframe integration on the performance of an airframe integrated scramjet through the measurement of internal pressure distribution and the direct measurement of the net lift, thrust and pitching moment using a three-component stress wave force balance. The engine chosen as the basis for this study was the Mach 12 rectangularto-elliptical shape-transition (m12rest) scramjet that was developed by Suraweera and Smart (2009) as a research engine for access-to-space applications. The inlet and combustor flowpath were integrated with a slender 6°wedge forebody, streamlined external geometry and three dimensional thrust nozzle. The scale of the engine was chosen so that the entire engine would fit within the core-flow diamond (bi-conic) produced by a Mach 10 facility nozzle. The Mach 10b facility nozzle was chosen because it is the largest nozzle current in use with the t4 Stalker Tube and because the offdesign performance of a scramjet engine is of interest for access-to-space vehicles that must accelerate over a range of Mach numbers.Freejet experiments were conducted within the t4 Stalker Tube. Two trueflight Mach 10 test conditions were used: a high pressure test condition that replicated flight at a dynamic pressure of 48 kPa and a low pressure test condition that replicated flight at a dynamic pressure of 28 kPa. Scaling of the test conditions according to the established binary scaling law was not completed due to facility operational limits.The engine featured two fuel injection stations from which gaseous hydrogen was injected. The first injection station was partway along the length of the inlet while the second injection station was at the start of the combustor behind a rearward facing circumferential step. In addition to investigating inlet-only and step-only injection, a combined scheme where 68 % of the fuel was injected from the step station and 32 % from the inlet station was also investigated.To support the analysis of the experimental results, numerical simulations of the engine with no fuel injection were conducted using the nasa code vulcan. Analysis of the simulations show that the mass capture ratio with respect to the projected inlet area is approximately 60 % at each test condition. The simulations also show that spillage of flow from the slender forebody accounts for just 12 % of the flow through the projected iii inlet area, a small but non-negligible fraction. By integrating the engine surface forces, the drag coefficient with respect ...

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Flow Physics Inside a Shape-Transitioning Scramjet Engine

Cited by 7 publications

References 14 publications

Effect of Streamwise Vortices on Scramjets Porthole Injection Mixing

Effect of Streamwise Vortices on Scramjets Porthole Injection Mixing

Effect of Vortex-injection Interaction on Wall Heat Transfer in a Flat Plate with Fin Corner Geometry

An experimental investigation of an airframe integrated three-dimensional scramjet engine at a Mach 10 flight condition

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