Orbital Delivery of Small Payloads Using Hypersonic Airbreathing Propulsion

Smart, Michael K.; Tetlow, Matthew

doi:10.2514/1.38784

Cited by 97 publications

(95 citation statements)

References 11 publications

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“…In the earlier work by Smart and Tetlow, 8 REST scramjet engines were included on a conical vehicle design. However, this work was a system level study addressing the operability of a 3-stage access-to-space vehicle, where the second stage was scramjet propulsion.…”

Section: Flow Field Considerations For a Conical Vehicle At Anglmentioning

confidence: 99%

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Design of Modular, Shape-transitioning Inlets for a Conical Hypersonic Vehicle

Gollan

Smart

2010

48th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition

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For a hypersonic vehicle, propelled by scramjet engines, integration of the engines and airframe is highly desirable. Thus, the forward capture shape of the engine inlet should conform to the vehicle body shape. Furthermore, the use of modular engines places a constraint on the shape of the inlet sidewalls. Finally, one may desire a combustor crosssection shape that is different from that of the inlet. These shape constraints for the inlet can be accommodated by employing a streamline-tracing and lofting technique. This design technique was developed by Smart for inlets with a rectangular-to-elliptical shape transition. In this paper, we generalise that technique to produce inlets that conform to arbitrary shape requirements. As an example, we show the design of a body-integrated hypersonic inlet on a winged-cone vehicle, typical of what might be used in a three-stage orbital launch system. The special challenge of inlet design for this conical vehicle at an angle-of-attack is also discussed. That challenge is that the bow shock sits relatively close to the vehicle body.

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Section: Flow Field Considerations For a Conical Vehicle At Anglmentioning

confidence: 99%

“…In the paper by Smart and Tetlow, 8 it was proposed to attach three modular scramjet engines to the wingedcone vehicle. In the spirit of working from their proposed design, an initial attempt was made to design an inlet which would be part of three modular scramjet engines stacked side-by-side.…”

Section: Choosing the Number Of Scramjet Modulesmentioning

confidence: 99%

Design of Modular, Shape-transitioning Inlets for a Conical Hypersonic Vehicle

Gollan

Smart

2010

48th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition

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“…UPERSONIC combustion ramjets (scramjets) offer a higher potential specific impulse over rockets between the flight Mach numbers of 6 to 14, providing a more economical means of delivering payloads into orbit [1,2]. A schematic is presented in the upper part of Fig.…”

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confidence: 99%

Numerical Investigation into the Combustion Behavior of an Inlet-Fueled Thermal-Compression-Like Scramjet

2015

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A numerical study on the combustion behavior of an inlet-fueled three-dimensional nonuniform-compression scramjet is presented. This paper is an extension to previous work on the combustion processes in a premixed threedimensional nonuniform-compression scramjet, where thermal compression was shown to enhance combustion. This paper demonstrates how thermal compression can be used in a generic scramjet configuration with a realistic fuelinjection method to enhance performance at high flight Mach numbers. Such a scramjet offers an extra degree of freedom in the design process of fixed-geometry scramjets that must operate over a range of flight Mach numbers. In this study, how the combustion processes are affected is investigated, with the added realism of inlet porthole fuel injection. Ignition is established from within a shock-induced boundary-layer separation at the entrance to the combustor. Radicals that form upstream of the combustor within the inlet, from the injection method, enhance combustion. Coupling of the inlet-induced spanwise gradients and thermal compression improves combustion. The results highlight that, although the fuel-injection method imparts local changes to the flow structures, the global flow behavior does not change compared to previous premixed results. This combustion behavior will be reproduced when using other fueling methods that deliver partially premixed fuel and air to the combustor entrance.

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“…The potential payload mass fraction of a three stage rocket-scramjetrocket system has increased to 1.87 % [2] from the typical values of between 0.36−1.26 % for single-use, rocket-based systems [3]. The reason for this is that scramjet engines have greater performance per propellant flow rate than rocket engines, as scramjets draw oxygen from the ingested air.…”

Section: Motivationmentioning

confidence: 94%

“…Whilst some water is also produced during the ignition process, the heat released is absorbed by the dissociation reactions and very little temperature rise is noted during this period. As such, 3 In low speed engines (M 0 ≤ 6) a constant area isolator is typically included between the intake and combustor [25] from stations 2−3. Its purpose is to isolate the intake from the effect of separation of the boundary layer in the combustor, which would cause an engine unstart.…”

Section: Combustion Systemmentioning

confidence: 99%

Experimental Investigation of a 3D Thermal Compression Scramjet Using Advanced Optical Techniques

Vanyai¹

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Scramjet engines are limited in performance due to engine starting problems at low hypersonic speeds. For an accelerating hypersonic vehicle, intake contraction ratios are typically fixed to the low speed starting requirements. This reduces engine performance at higher Mach numbers, where higher contraction ratios are required to efficiently combust flow within a practically-sized combustor.The use of a combustion process called "Thermal Compression" was suggested in the 1960s that could improve the performance of low intake contraction scramjet engines. In such an engine, the flow field is non-uniform within the combustor, with regions of locally high pressure and temperature even at low net intake contraction ratio. The flow properties in these regions are suitable for combustion of air-fuel mixtures, inducing autoignition. As heat is released, increased temperature and pressure are transmitted to the surrounding flow through pressure waves. Conditions in the surrounding flow become suitable for combustion, and this process continues until combustion completes throughout the entire flow field.This work presents results from experimental and numerical analysis of a three-dimensional, thermal compression scramjet engine at two high Mach number flight conditions. Experiments were conducted in the T4 Shock Tunnel at The University of Queensland. The tunnel test gas simulated flow that had been processed by an engine forebody at either 8.0• or 8.8• angle of attack, in an equivalent flight condition of Mach 10, 50 kPa dynamic pressure.An engine test model was developed to examine the effect of thermal compression on combustion-induced pressure rise at these inflow conditions. Non-uniform combustor flow was generated using a three-dimensional intake with a ramp angle that varied in the spanwise direction. This produced a low compression side and a high compression side throughout the scramjet engine. Fuel injection plenums were split such that different gases could be injected in either the low compression or high compression side. Combustion was induced by injecting hydrogen fuel, or suppressed by injecting helium.i Pressure measurements were taken along the streamwise length of the engine, in three spanwise locations. Optical techniques, including emission and laser-induced fluorescence (LIF) methods, were used to visualise the distribution of OH radicals throughout the combustor. These experimental results were then compared to fully-combusting, RANS CFD simulations.The influence of thermal compression was determined by comparing combustion-induced pressure rise in the fully-fuelled case to the sum of both cases where combustion was suppressed on each side of the engine. It was found that for the forebody angle of 8.8• case, thermal compression increased pressure rise by 14.4 ± 6.0 % and 6.7 ± 6.2 % for fuel-air equivalence ratios of φ = 0.8 and φ = 1.0 respectively. Emission from OH radicals, which is qualitatively indicative of combustion, also increased by 19 -54 % in the rear of the combustor. Numerica...

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Orbital Delivery of Small Payloads Using Hypersonic Airbreathing Propulsion

Cited by 97 publications

References 11 publications

Design of Modular, Shape-transitioning Inlets for a Conical Hypersonic Vehicle

Design of Modular, Shape-transitioning Inlets for a Conical Hypersonic Vehicle

Numerical Investigation into the Combustion Behavior of an Inlet-Fueled Thermal-Compression-Like Scramjet

Experimental Investigation of a 3D Thermal Compression Scramjet Using Advanced Optical Techniques

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