The domain of the scramjet

Townend, L. H.

doi:10.1098/rsta.1999.0433

Cited by 12 publications

(9 citation statements)

References 23 publications

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“…Lewis [12] has demonstrated that for a cruiser operating in the Mach 8-10 corridor, in which it is desired to maximize cruise range for a given total takeoff weight, the aerodynamic and volumetric advantages of storable hydrocarbons are about equivalent or superior to the specific impulse advantages of hydrogen in determining cruiser range. Additionally, Townend [8] has summarized that hydrocarbon would be the fuel of choice for a variety of scramjet operations, including both the airbreather and rocket modes of a small SSTO military use (cruise and space access) vehicle and the second stage of an even smaller, TSTO vehicle. Table 2.1 is a comparison of properties of potential scramjet fuels [15].…”

Section: Fuelsmentioning

confidence: 99%

“…Many ideas have been proposed addressing the specific function of the scramjet during any given mission. Townend [8] highlights several options for scramjet implementation: Current research focuses mainly on these as well as implementation in rocket-based combined cycle (RBCC) engines and global presence, hydrocarbon-fueled missiles [9].…”

Section: Current Trends In Hypersonic Researchmentioning

confidence: 99%

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Plasma Torch Atomizer-Igniter for Supersonic Combustion of Liquid Hydrocarbon Fuels

Billingsley¹,

O’Brien²,

Schetz³

2006

14th AIAA/AHI Space Planes and Hypersonic Systems and Technologies Conference

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To realize supersonic combustion of hydrocarbons, an effective atomizer-igniter combination with the capabilities of fuel preheating, atomization, penetration, mixing, ignition and flameholding is desired. An original design concept incorporating these capabilities was built and tested at Virginia Tech, and was found to provide good penetration, effective atomization, and robust ignition and flameholding. Quiescent testing with kerosene and JP-7 provided initial performance data. The atomizer-injector design was then modified for insertion In the quiescent environment, the regeneratively cooled plasma torch igniter was found to significantly increase electrode life while heating, atomizing, and igniting the liquid fuel. Jet breakup length was measured and characterized, and mean droplet size was estimated using an existing correlation. Several qualitative observations regarding quiescent combustion were made, including torch power effects and the process of flame formation. In the supersonic environment, the effect of fuel injection direction was analyzed. Best results were obtained when fuel was injected with a velocity component opposite to the direction of main tunnel flow. Repeatable ignition occurred in the supersonic boundary layer at the fuel stagnation location near the plasma torch plume. Direct, filtered, shadowgraph, and schlieren photographs, temperature ii measurements, and visible emission spectroscopy provided evidence of combustion and the details of the flame structure.The new atomizer-igniter design provided robust and reliable ignition and flameholding of liquid hydrocarbon fuels in an unheated supersonic flow at M=2.4, with no ramp, step, or other physical penetration into the flowpath.iii Acknowledgements Dr. O'Brien, I enjoyed the relaxed lab atmosphere, and am grateful for your unique ability to promote progress without being overbearing. Thank you for recognizing my circumstances, and being flexible as I managed my young family. Thank you for the enthusiasm you show for your research; it was a privilege and a joy working with you.

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Section: Fuelsmentioning

confidence: 99%

Section: Current Trends In Hypersonic Researchmentioning

confidence: 99%

Plasma Torch Atomizer-Igniter for Supersonic Combustion of Liquid Hydrocarbon Fuels

Billingsley¹,

O’Brien²,

Schetz³

2006

14th AIAA/AHI Space Planes and Hypersonic Systems and Technologies Conference

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“…The principle of scramjet technology, its advantages, and the interest to use hydrocarbon fuel to cool down the engine have been fully studied in the literature [12][13][14][15]. Compared to cryogenic hydrogen, heavy hydrocarbon fuels are safer and much simpler to use, their costs are lower, and they conduct to smaller vehicles because their density is higher than that of cryogenic fuels.…”

mentioning

confidence: 99%

Validation of Transient Cooling Modeling for Hypersonic Application

Gascoin

Gillard

Dufour

et al. 2007

Journal of Thermophysics and Heat Transfer

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Hypersonic flight is expected to be achieved in the coming years by use of supersonic combustion ramjet. One of the main issues is the thermal management of the overall vehicle and more specifically the cooling of the engine. To simulate the behavior of an actively cooled supersonic combustion ramjet by use of supercritical endothermic fuel, a one-dimensional transient numerical model has been developed with heat and mass transfer, fluid mechanics and detailed pyrolysis chemistry. A supplementary step by step validation of the model is presented in this paper thanks to numerical and experimental comparison test cases. Fluid temperature profiles are in good agreement for steadystate calculations despite unconsidered 2-D effects due to momentum and thermal boundary layers. Heat fluxes conservation is verified. Thermal and hydraulic transient behavior are close to those of validation data. The present numerical modeling is quantitatively validated under steady state and transient conditions. Good agreement is found with experimental results on a chemical aspect. The model is suitable for conducting parametric studies on fuel pyrolysis in supercritical states and to use it for engineering applications as a predimensioning tool.

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“…Research on flights above supersonic and hypersonic speeds continues to gain attention in countries throughout the globe for their applications in economical space access, military technology and commercial transportation (Curran, 2001;Townend, 2001). While conventional rockets still continue to be the main space access vehicles, operations within the atmosphere at high speeds present more challenges due to the necessity of oxidiser leads that limits the craft's range and payload mass.…”

Section: Introductionmentioning

confidence: 99%

“…However, the conventional ramjet's reliance on subsonic combustion process limits its flight capabilities to applications below Mach 5. This is caused by the big increase in stagnation pressure and temperature to slow the high velocity freestream to achieve subsonic combustion as flights enter hypersonic flight regimes (Townend, 2001). From there, supersonic combustion ramjets or scramjets gained attention due to its capabilities to add heat directly to a supersonic flow and ability to overcome the limitations of the ramjet engine (Curran, 2001).…”

Section: Introductionmentioning

confidence: 99%

Effect of injection strategy and mainstream combustion on skin friction reduction through boundary layer combustion in scramjet combustors

Ngo¹

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AcknowledgementsI would first like to thank my supervisor, Dr Vincent Wheatley. Without him, this thesis would not have been possible, both figuratively and literally. The weekly meetings I have had with him were always informative and it also served as a constant reminder for myself to get my act together and work hard. There was never a time that I did not felt welcome and his cheerful disposition always makes my day better after a tough week working on this thesis. I have learned just as much from these short meetings every week than I have in many other courses, if not more.I would also like to thank my friends who make university life a less boring place. And for putting up with my constant rants about my simulations not working and the occasional nonsensical babbling of technical details. It was nice to take breaks from studies to hang out and chat. A 2 dimensional, axisymmetric scramjet combustor with a slot injector was modelled to investigate the effects of mainstream combustion. The freestream inlet used in this model consists of a developed flow generated from a triple ramp axisymmetric inlet at Mach 8. Results obtained from the simulations determined that mainstream combustion increased the effectiveness of boundary layer combustion in skin friction reduction. It was observed that skin friction drag reduction performance improved by up to 50% compared to the case when no mainstream combustion is present. A grid convergence study was also conducted and it was determined that the simulated solutions are grid-independent.Comparison of fuel injection strategies between a porous wall injection and slot injection was performed by modelling one porous wall. The comparison is done for the model with mainstream combustion and boundary layer combustion. However, the porous wall model did not undergo a comprehensive analysis like the slot injector case and the sole porous wall model simulation conducted, while converged, could be further improved. The preliminary results observed determined that the porous wall injection performed better than slot injection and achieved a 40% lower total viscous drag force inside the simulated scramjet combustor.

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The domain of the scramjet

Cited by 12 publications

References 23 publications

Plasma Torch Atomizer-Igniter for Supersonic Combustion of Liquid Hydrocarbon Fuels

Plasma Torch Atomizer-Igniter for Supersonic Combustion of Liquid Hydrocarbon Fuels

Validation of Transient Cooling Modeling for Hypersonic Application

Effect of injection strategy and mainstream combustion on skin friction reduction through boundary layer combustion in scramjet combustors

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