Combustion Scaling Laws for Inlet-Fueled Scramjets

Schloegel, Fabrice

doi:10.14264/uql.2014.124

Cited by 3 publications

(13 citation statements)

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“…Chemistry time scales play an important role in the the overall chemistry and combustion process. The chemistry time scale of a reaction is proportional to the fluid pressure raised to the exponent of the order of reaction (n) minus one and is also a function of temperature 4 , based on the solution to a simple single step reaction mechanism (Kuo 2005) [15], (Schloegel 2014) [25], as shown in Equation 2.6. The nonlinear coupling of reactive systems, the occurrence of both binary and tertiary reactions and the occurrence of reactions with large time scales leading to stiff solutions however complicates the actual relationship between the time scale and pressure.…”

Section: Chemical Time Scalesmentioning

confidence: 99%

“…In the case of the 0.1 length scale simulation combustion is inhibited until approximately 0.85 combustor lengths leading to a drastically altered flowfield structure. Schloegel (2014) [25] completed a numerical and experimental investigation examining the influence of pressure on ignition delay and chemistry heat release length scales in a two dimensional inlet-fuelled radical farming scramjet. The objective of this study was to determine whether Pressure-Length scaling, presented in Equation 2.18, could describe the relationship between pressure and the location of ignition and heat release within the engine.…”

Section: Scaling Studies Of Scramjetsmentioning

confidence: 99%

“…It requires an internal shock train structure in order to achieve combustion at combustor inlet temperatures and pressures milder than conventional designs and is sensitive to the three dimensional internal shock structure coupled to the chemistry. Although Schloegel (2014) [25]'s study examined radical farming scramjet engines, the engine was two dimensional in nature and the study examined the effects of altering pressure on the ignition and heat release length scales at a constant combustor length; no effects of geometric length scale were examined.…”

Section: Length Scaling Of Radical Farming Scramjet Enginesmentioning

confidence: 99%

“…It is a unified computing, unified grid, unified physics numerical code capable of modelling flows across the entire flight spectrum from subsonic through to hypersonic and reentry flows, in addition to multiphase flows, with reacting flowfields and a range of turbulence models. CFD++ has been successfully employed to reconstruct experimental scramjet engine flowfield data in the studies of Hunt (2014) [37], McGuire (2007) [36] and Schloegel (2014) [25].…”

Section: Cfd++mentioning

confidence: 99%

“…All three models showed similar flowfield structures and predicted a separation forming in the same region of the flowfield, with the size of the separation bubble within 13% of each simulation. The two-equation SST turbulence model has also been employed on radical farming scramjet engine simulations in the studies of Hunt (2014) [37] and Schloegel (2014) [25]. Both studies successfully reconstructed experimental wall data with this approach to turbulence modelling.…”

Section: Turbulence Modellingmentioning

confidence: 99%

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Geometric scaling studies of an inlet-fuelled axisymmetric radical farming scramjet engine

Oberg¹

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Scramjet engine technology has the potential to transform commercial flight and mankinds' ability to access space. Major technology hurdles remain which must be investigated and resolved before the potential of the scramjet engine can be realised. The ability to scale a small geometric scale scientific test model to a large practical vehicle size with similar performance characteristics is one such challenge. In this study, the small scale geometric scaling characteristics of a scramjet engine, one such tool to aid in future experimental based investigations and overall scramjet development, is presented. The study specifically concentrates on investigating the similarity effects for a new type of scramjet engine, the axisymmetric inlet-fuelled radical farming scramjet engine, and is concerned with the Pressure-Length scaling laws in both plain air mediums and hypersonic shock tunnel facility test mediums.

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Section: Chemical Time Scalesmentioning

confidence: 99%

Section: Scaling Studies Of Scramjetsmentioning

confidence: 99%

Section: Length Scaling Of Radical Farming Scramjet Enginesmentioning

confidence: 99%

Section: Cfd++mentioning

confidence: 99%

Section: Turbulence Modellingmentioning

confidence: 99%

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Geometric scaling studies of an inlet-fuelled axisymmetric radical farming scramjet engine

Oberg¹

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Adaptive grid implementation for parallel continuum mechanics methods in particle simulations

Mehl

Lahnert

2019

Eur. Phys. J. Spec. Top.

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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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Combustion Scaling Laws for Inlet-Fueled Scramjets

Cited by 3 publications

References 0 publications

Geometric scaling studies of an inlet-fuelled axisymmetric radical farming scramjet engine

Geometric scaling studies of an inlet-fuelled axisymmetric radical farming scramjet engine

Adaptive grid implementation for parallel continuum mechanics methods in particle simulations

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

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