Full Free-stream Mach 12 Scramjet Testing in Expansion Tubes

Toniato, Pierpaolo; Gildfind, David; Andrianatos, Andreas; Morgan, Richard G.

doi:10.2514/6.2018-3818

Cited by 5 publications

(7 citation statements)

References 23 publications

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“…4 Layout of Bezier control points 90 Figure 4. 5 An example of the solutions explored by the optimiser at every iteration 91 Nozzle and dump tank Mach number contours 94 Figure 4. 10 Nozzle and dump tank flow angle contours 95 Figure 4.…”

Section: Declaration By Authormentioning

confidence: 99%

“…4 Shock surfaces over cone probe 116 Figure 5. 5 Normal shock wave forming at the inlet rake 116 Figure 5.6 X3 expansion tube test section, enclosing Mach 12 nozzle and inlet rake 117 Nozzle exit plane probe locations 117 Figure 5. 9 Nozzle inlet conehead aggregated pressure profiles 120 Figure 5.…”

Section: Declaration By Authormentioning

confidence: 99%

“…4 Normalised pressure difference between fuelled and unfuelled experiments: combustor-only injection 174 Figure 7. 5 Experimental pressure distributions for combined injection: unstarts 175 Figure 7. 6 Forebody pressure traces with helium and air acceleration tube 177 Figure 7.…”

Section: List Of Figuresmentioning

confidence: 99%

“…4 Calculated fill conditions for Mach 12 operating condition 60 Table 3. 5 Nominal Mach 12 operating conditions 61 Table 3. 6 Facility operating parameters for facility-configuration tests 63 Table 3.…”

Section: List Of Figuresmentioning

confidence: 99%

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Free-jet testing of a Mach 12 scramjet in an expansion tube

Toniato¹

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Scramjet technology has the theoretical potential to provide air-breathing propulsion as a more efficient alternative to conventional rocket propulsion. Since the vehicle captures its oxidiser from the atmosphere -as opposed to carrying it like a rocket -the specific impulse can theoretically be increased by an order of magnitude, thereby increasing payload mass fractions. In this context, threestage hybrid rocket-scramjet-rocket launch systems have shown to potentially provide a cost-effective and flexible solution for satisfying the requirements of the small-satellites market. However, to be economically feasible, the proposed scramjet-powered second stage would be reusable.Rectangular-to-Elliptical-Shape-Transitioning (REST) engines have shown to be a viable concept that can be integrated into access-to-space vehicles operating between Mach 5 and 12. The half-scale Mach 12 REST engine is a research scramjet specifically designed to operate in the last part of the ascent trajectory. Previous studies have demonstrated the ability of this design to successfully operate at equivalent flight conditions of Mach 11.6, 30 kPa dynamic pressure. However, tests have never been performed in freejet mode at the design conditions, as the facility which was used -the T4 reflected shock tunnel -was limited, like all RSTs by the extreme total pressure requirements of a Mach 12 flight. These limitations are aggravated by the even higher pressure necessary for pressure-length scaling, used to conserve the flow similarity between the half-scale experimental model and the flight engine.To overcome these limitations and allow freejet testing with pressure-length scaling, the use of expansion tubes has been proposed. These are currently the only kind of facility capable of producing these high-pressure requirements. Currently, the University of Queensland operates the X3 expansion tube, which is one of the few facilities worldwide with the potential to produce both the required total pressures and sufficiently long test times (up to 1.5 ms) to test an engine such as the Mach 12 REST engine.

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Section: Declaration By Authormentioning

confidence: 99%

Section: Declaration By Authormentioning

confidence: 99%

Section: List Of Figuresmentioning

confidence: 99%

Section: List Of Figuresmentioning

confidence: 99%

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Free-jet testing of a Mach 12 scramjet in an expansion tube

Toniato¹

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“…However, this had the potential to entrain large diaphragm fragments into the test flow, which could do considerable damage to the experimental model being tested. More recently, following the success of scored diaphragm usage in the X2 expansion tube, diaphragm scoring was adopted for standard X3 operation [41] to ensure a cleaner, repeatable opening, as well as to allow customisation of the diaphragm rupture pressure through score depth adjustment.…”

Section: The X3 Super-orbital Expansion Tubementioning

confidence: 99%

Development of an extended test time operating mode for a large reflected shock tunnel facility

Stennett¹

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X3R is a new free-piston driven reflected shock tunnel (RST) facility, derived from the X3 free-piston super-orbital expansion tube at the University of Queensland (UQ). X3R is the first dual-mode impulse facility in Australia, and is also the first dual-mode free-piston impulse facility originating as an expansion tube. Conversion and operation of the facility in a reflected shock tunnel mode was originally envisioned as a means to increase the scale and duration of Australia's hypersonic testing capability, which was previously limited in both aspects in comparison to other international impulse facilities. This thesis was completed to coincide with the physical X3R facility hardware design and development, to produce an operating condition capable of generating and maintaining a Mach 7, 50 kPa dynamic pressure test flow for 10 ms. It was initially postulated that this could be efficiently achieved using the pre-existing X3 facility hardware, new components designed specifically for reflected shock tunnel mode, and a new operating condition. Due to its parallel operation as an expansion tube, X3R featured a driver tube length that was 60% that of the shock tube in RST mode. These geometric proportions are unique compared to other facilities of this kind throughout the world, which typically feature driver tubes that are at least twice the shock tube length. Operation of a reflected shock tunnel with such a relatively short driver tube makes it extremely challenging to efficiently utilise the 'full' slug of test gas. The primary challenge was generating a pulse of gas from the driver with sufficient duration to fully shock the test gas and sustain critical flow processes until 10 ms of test flow at the target conditions had been generated. The solution to this challenge was careful configuration of the free-piston driver and quite unconventional driver operation. Theoretical analysis showed that a very low compression ratio was required to maximise the volume of the driver gas. Given the low compressive heating, this resulted in a much higher helium fraction that would be normally required to produce a free-piston driven 1400 m/s shock through air. The low compression ratio then required significant piston energy to compress the gas, leading to extended periods of high facility and piston loading. Sustaining a relatively steady driver gas pressure to drive the downstream flow processes required piston speed to be maintained immediately after diaphragm rupture. This driver gas 'hold time' was shown to depend on piston mass; the higher the driver gas pressure, the heavier the piston needed to be to sustain a given test time. Once this fundamental dependency had been identified, it was determined that if piston mass and test flow dynamic pressure were fixed, there was a maximum test time that could be achieved. Conversely, if piston mass and test time were specified, there was a fundamental limit to the achievable test flow dynamic pressure. For the initial configuration analysed in this thesis, it was found that, ...

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Large-scale free-piston-driven multi-mode shock expansion tunnel

Stennett,

Gildfind,

Andrianatos

et al. 2024

Exp Fluids

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X3/R is a new large-scale free-piston-driven dual-mode shock expansion tube, developed and operated collaboratively by the University of Queensland (UQ) and Australia’s Defence Science and Technology Group (DSTG). The facility can be converted between a long-duration reflected shock tunnel (RST), a super-orbital expansion tube (X-mode), and a non-reflected shock tube (NRST). In RST mode, the facility is currently capable of producing 600 mm diameter Mach 7 test flows at 25–50 kPa dynamic pressure for more than 10 ms. In expansion tube mode, the facility can reach enthalpies up to 80 MJ/kg for test times on the order of 500–1000 $${\mu }$$ μ s. This paper presents the new facility, summarizes its current operational capabilities, and discusses key the technical challenges overcome during its development.

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Full Free-stream Mach 12 Scramjet Testing in Expansion Tubes

Cited by 5 publications

References 23 publications

Free-jet testing of a Mach 12 scramjet in an expansion tube

Free-jet testing of a Mach 12 scramjet in an expansion tube

Development of an extended test time operating mode for a large reflected shock tunnel facility

Large-scale free-piston-driven multi-mode shock expansion tunnel

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