Operability Benefits of Airbreathing Hypersonic Propulsion for Flexible Access to Space

Flaherty, Kevin W.; Andrews, Katherine M.; Liston, Glenn

doi:10.2514/1.43750

Cited by 44 publications

(18 citation statements)

References 9 publications

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“…Scramjets are propulsion systems that use atmospheric oxygen in their combustion chambers, rather than carrying it on-board like a traditional rocket engine. Hypothetical launch vehicles have been proposed that offer significant advantages in launch operability 6 and payload mass fraction to orbit, 28 but to compete with currently available systems research into methods of drag reduction or combustion efficiency enhancement are needed. Typical scramjet concepts use a relatively large amount of inlet compression to heat and pressurize incoming air past the autoignition temperature of their fuel, which can result in significant total pressure losses.…”

Section: Introductionmentioning

confidence: 99%

Simulation of Laser-Induced-Plasma Ignition in a Hypersonic Crossflow

Gibbons

Gehre

Brieschenk

et al. 2015

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

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A numerical study of a laser-induced-plasma ignition system in a scramjet-like geometry is conducted. Simulations are based on experiments in which hydrogen is injected into hypersonic air-crossflow, compressed by a 9 • ramp from a freestream Mach number of 8 to below hydrogen autoignition conditions. Ignition of the jet is conducted using a laser pulse, modelled in the simulations as a small region of high temperature and pressure corresponding to the energy input measured in the experiments. To capture the highly unsteady nature of the fuel-air interface and its coupling with the dynamics of the expanding laser spark, Wall-Modelled Large Eddy Simulations are used to resolve the majority of turbulent motion. Detailed non-equilibrium thermochemistry models are included in the calculations. Simulations have revealed that the cloud of hydroxyl radicals detected in the experiments is created by the blast wave which forms from the expanding plasma kernel merging with the jet's bow shock. This event raises the temperature and pressure in the upstream mixing layer and spontaneous ignition of the fuel is observed. Shortly after this ignition, combustion ceases due to hostile conditions for flame anchoring. Downstream of the jet, the simulations suggest that the plasma kernel remains can initiate some radical formation in the wake region, but no stable flame forms due to nominally low pressures in the experimental condition studied.

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Section: Introductionmentioning

confidence: 99%

Simulation of Laser-Induced-Plasma Ignition in a Hypersonic Crossflow

Gibbons

Gehre

Brieschenk

et al. 2015

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

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show abstract

“…Though no such system has yet to fly, it is generally accepted that performance gains with respect to rocket-based systems could be obtained in the areas of reuseablity, safety margins, and the ability to undertake abort missions or downrange manuverability. [1][2][3] All these aspects are generally attributable to aircraft operations, rather than rockets. Increased payload-to-orbit mass fractions and lower launch costs may also be possible.…”

Section: Introductionmentioning

confidence: 99%

Measurement of Three-Components of Force on an Airframe Integrated Scramjet at Mach 10

Doherty¹,

Smart²,

Mee³

2015

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

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Force balance experiments have been conducted within The University of Queensland's T4 Stalker Tunnel with a small airframe-integrated three-dimensional scramjet engine using a three-component stress wave force balance. The tests were conducted at conditions replicating flight at Mach 10 and a dynamic pressure of 52 kPa or 28 kPa. The internal flowpath featured a rectangular-to-elliptical shape transition (REST) inlet, an elliptical combustor with a constant area and a diverging section, and a three-dimensional thrust nozzle. This flowpath was integrated with a forebody and streamlined external geometry to provide the test model. Gaseous hydrogen fuel was injected either through portholes on the inlet, from a series of portholes behind the rearward facing step at the combustor entrance, or a combination of the two. The fuel-off drag coefficient was measured to be 0.246 ± 0.025 and 0.312 ± 0.032 at the high and low dynamic pressure test conditions respectively. At a fuel equivalence ratio of 1.20, the drag coefficient reduced to 0.118 ± 0.034 for a combined injection scheme at the high dynamic pressure test condition, corresponding to a specific impulse increment of 2160 s and a specific thrust increment of 740 N s/kg. This work represents the first time that force data have been measured for a hydrogen fuelled REST scramjet engine at true-flight Mach 10 test conditions. NomenclatureA area, m 2 A axial direction, m a axial coordinate, m A o output specification matrix A F projected frontal area, m 2 A p projected planar or planform area, m 2 a vi element of output specification relating strain output v to stress bar i outputheat of formation, J/kg ρ density, kg/m 3 d k j moment arm for calibration hit in direction k at calibration location j, m F force, N

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“…[1][2][3][4][5] In order to initiate a scramjet program pre-conceptual design and related analysis shall be performed. On the other hand there must be many experiments done in order to maintain and conclude the scramjet program with a robust product.…”

Section: Introductionmentioning

confidence: 99%

Design and Optimization of a Notional Scramjet by Means of Stream Thrust Analysis and Design of Experiments

Akpolat

Toker²,

Genç

2014

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

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Within the scope of this study, a 0-dimensional code is developed by using Stream Thrust Analysis in order to evaluate scramjet cycle performance with respect to selected performance parameters (specific impulse, overall efficiency) and combustion chamber exit temperature. By using the results of this code an analysis employing "Design of Experiments" (DoE) is performed to determine the most effective input parameters and/or interactions on the scramjet performance. The results showed that most effective input parameter for all of the selected parameters is fuel/air ratio. Selected parameters are evaluated first individually then simultaneously. The purpose of evaluating the performance parameters simultaneously is to determine the input parameter set which gives the highest values of specific impulse and overall efficiency while giving the lowest value of combustion chamber exit temperature. As a result the input parameter sets for different cases are determined.

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Operability Benefits of Airbreathing Hypersonic Propulsion for Flexible Access to Space

Cited by 44 publications

References 9 publications

Simulation of Laser-Induced-Plasma Ignition in a Hypersonic Crossflow

Simulation of Laser-Induced-Plasma Ignition in a Hypersonic Crossflow

Measurement of Three-Components of Force on an Airframe Integrated Scramjet at Mach 10

Design and Optimization of a Notional Scramjet by Means of Stream Thrust Analysis and Design of Experiments

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