A Study of Expansion Tube Gas Flow Conditions for Scramjet Combustor Model Testing

Gamba, Mirko; Adams, Nikolaus A.; Iaccarino, Gianluca

doi:10.2514/6.2012-3264

Cited by 6 publications

(9 citation statements)

References 17 publications

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“…An account of the design and operation of this facility is given by Heltsley et al; 58 recent modeling efforts of this facility have been attempted by Örley et al 59,60 A more detailed accounting of the operation and calibration of the facility to produce the desired conditions used in this studies are also presented elsewhere 27,56,57,61 and are thus not repeated here in detail. The operational principle and a theoretical analysis of the performance of an expansion tube to generate high-enthalpy supersonic and hypersonic flows can be found in the seminal work of Trimpi.…”

Section: A Flow Facility: the Expansion Tubementioning

confidence: 98%

The reacting transverse jet in supersonic crossflow: physics and properties (invited)

Gamba

Miller

Mungal

2014

19th AIAA International Space Planes and Hypersonic Systems and Technologies Conference

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Combustion in the supersonic regime presents several challenges when compared to its low-speed counterpart. Here we review some of these challenges, and we describe some of the key features of one of the canonical flow fields in supersonic combustion: the reacting transverse jet in a supersonic crossflow (JISCF). From a practical standpoint, the key challenges that limit the control of this combustion regime are fast mixing, robust flame holding and stability. In turn, these aspects are controlled by the complex effects introduced by chemistry, compressibility, shocks and shock/flow interactions, turbulence and the underlying coupling among them. Some of their properties are discussed here. In particular, for a JISCF in a Mach 2.4 high enthalpy crossflow, the reaction zone structure, its dependence on near-wall events, boundary layer, and shock/boundary layer interaction are described. We demonstrate the paramount importance of the coupling between boundary layers and compressibility to provide mechanisms for flame stabilization at the wall. Mixing characteristics, overall structure, and the link to global parameters (momentum flux, velocity and density ratios) that characterize the JISCF, and possibly free shear supersonic flows in general, is also highlighted from non-reacting experiments. Nomenclature d = Jet exit diameter J = Jet-to-crossflow momentum flux ratio, ρ jet U 2 jet ρ a U 2 a M = Mach number p = Pressure p j,o = Jet stagnation pressure Re d = Injector jet exit Reynolds number, ρ jet U jet d µ jet r = Velocity ratio, U jet /U a s = Density ratio, ρ jet /ρ a T = Temperature U = Speed x = Streamwise direction y = Wall-normal direction z = Spanwise direction Greek letters: µ = Dynamic viscosity ρ = Density Subscript: a = Freestream conditions

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Section: A Flow Facility: the Expansion Tubementioning

confidence: 98%

The reacting transverse jet in supersonic crossflow: physics and properties (invited)

Gamba

Miller

Mungal

2014

19th AIAA International Space Planes and Hypersonic Systems and Technologies Conference

Self Cite

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“…The turbulent boundary layer in the expansion tube was simulated [17] in conjunction with the HYPULSE facility. It was reported in recent studies that the growth of turbulent boundary layer in the expansion tube is a critical issue limiting the test time of a shock-expansion tube [4,11]. The major objective of relevant computational investigations is to estimate the test time and test flow properties of the ground-based hypervelocity facilities [11,18].…”

Section: Introductionmentioning

confidence: 99%

“…It was reported in recent studies that the growth of turbulent boundary layer in the expansion tube is a critical issue limiting the test time of a shock-expansion tube [4,11]. The major objective of relevant computational investigations is to estimate the test time and test flow properties of the ground-based hypervelocity facilities [11,18]. However, it has been a great challenge to simulate and capture the essence of the complex flow dynamic phenomena in the SET, especially contributed by the chemically and thermally non-equilibrium effects under such high-enthalpy conditions.…”

Section: Introductionmentioning

confidence: 99%

“…A shock-expansion tube (SET) has the potential to mitigate the aforementioned concerns to a certain extent and generate relatively clean test gas of very high enthalpy and hypervelocity because the test flow is not stagnated anywhere. A series of SETs have been set up around the world, e.g., X-2 and X-3 at the Queensland University [1][2][3][4], HYPULSE at GASL [5], LENS-X at CUBRC [6], JX-1 in Japan [7,8], a SET of low-speed range for the investigation of scramjet at Stanford University [9][10][11], and others [12]. A detonation-driven SET has been built at the State Key Laboratory of High Gas Dynamics (LHD) and has successfully generated hypervelocity test flows of up to 8 km/s and beyond [13,14].…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, the split flux F AE m ¼ ðRK AE LÞ m U m ; ðm ¼ i À 1; i; i þ 1; i þ 2Þ for the original DCD scheme can be manually simplified via matrix manipulation to obtain a compact term as given in Eq. (11). The original DCD scheme is easy for programming and computationally cheap due to the aforementioned simplicity which has been used successfully in a series of applications [21][22][23][24][25][26][27] except the simulation of shockexpansion tube running at high enthalpy.…”

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confidence: 99%

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On the numerical technique for the simulation of hypervelocity test flows

Hu¹,

Wang²,

Jiang³

et al. 2015

Computers & Fluids

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a b s t r a c tA shock-expansion tube (SET) is one of the major ground test facilities to generate really high-enthalpy and hypervelocity test flows. However, the strong shock wave may give rise to chemically non-equilibrium characteristic flow feature in a SET. In addition, the test time duration of a SET is extremely short which leads to difficulties in measurements and flow diagnostics. It is therefore appropriate to consider employing CFD approach, coupled with available experimental data, to determine the characteristic of the test flow in a SET. The dispersion-controlled dissipative scheme (DCD) is used for our simulation of chemically non-equilibrium flows associated with a SET. In this paper, the several numerical issues which occur in the computational investigation of the test flow in our SET facility are discussed. A new flux splitting algorithm based on local characteristics is worked out for the DCD scheme to mitigate any spurious oscillations. With the mentioned updated DCD scheme, the computed results compare well with the experimental data provided for validation.

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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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A Study of Expansion Tube Gas Flow Conditions for Scramjet Combustor Model Testing

Cited by 6 publications

References 17 publications

The reacting transverse jet in supersonic crossflow: physics and properties (invited)

The reacting transverse jet in supersonic crossflow: physics and properties (invited)

On the numerical technique for the simulation of hypervelocity test flows

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

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