Incomplete Mixing and Off-Design Effects on Shock-Induced Combustion Ramjet Performance

Sislian, J. P.; Dudebout, Rudolph; Schumacher, J.; Islam, M. N.; Redford, T.

doi:10.2514/2.5529

Cited by 41 publications

(18 citation statements)

References 3 publications

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“…Sislian et al [11] and Redford [12] investigated the effects of incomplete fuel/air mixing and off-design flight conditions on the performance of shcramjet engine. Results showed that incomplete mixing led to a combination of detonation and shock-induced combustion.…”

Section: Fuel/air Premixingmentioning

confidence: 99%

Research status of key techniques for shock-induced combustion ramjet (shcramjet) engine

Huang

Qin

Luo

et al. 2010

Sci. China Ser. E-Technol. Sci.

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As one of the most promising propulsion systems in the future, shock-induced combustion ramjet engine can remedy the disadvantages in the integrated design of scramjet engine and airframe. It can shorten the length of the combustor, lighten the structure weight of the engine and keep better performance in a broad range of flight Mach number. The elementary principle of shockinduced combustion ramjet engine is introduced. The key technologies of this kind of propulsion system are described, while their research status is presented in detail. Suggestion on the development of shcramjet engine in China is put forward. aerospace propulsion system, shock-induced combustion ramjet engine, premature ignition, premixed efficiency, denotationCitation: Huang W, Qin H, Luo S B, et al. Research status of key techniques for shock-induced combustion ramjet (shcramjet) engine. Sci China Tech Sci, 2010, 53: 220−226,

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Section: Fuel/air Premixingmentioning

confidence: 99%

Research status of key techniques for shock-induced combustion ramjet (shcramjet) engine

Huang

Qin

Luo

et al. 2010

Sci. China Ser. E-Technol. Sci.

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“…These studies assumed an optimistic perfectly stoichiometric mixture before the detonation wave. Sislian et al [2] further examined the effects of off-design flight and incomplete fuel/ air mixing on shcramjet performance. Assuming Gaussian distributions of fuel, with peak values along the walls from which fuel is presumed to be injected, it was found that engines designed to produce detonation waves resulted instead in shock-induced/ detonation combustion combinations.…”

mentioning

confidence: 98%

Hypervelocity Fuel/Air Mixing in Mixed-Compression Inlets of Shcramjets

2006

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This paper investigates the mixing of hydrogen fuel with air in the mixing duct of a mixed-compression shockinduced combustion ramjet (shcramjet) inlet. Mixing augmentation through the use of cantilevered ramp injector arrays on opposite shcramjet inlet walls is studied and the influence of relative array locations is quantified. Studies were undertaken numerically using the WARP code that solves the Favre-averaged Navier-Stokes equations closed by the Wilcox k-! turbulence model. Air-based mixing efficiencies of up to 0.58-0.68 were achieved with thrust potential losses less than that gained from high-speed fuel injection. Shocks created from the fuel injector structures play a major role in the mixing behavior of the fuel jets on the opposing side of the mixing duct. Chemically reacting studies verified for the correct selection of spanwise displacement of the fuel injectors, an air buffer created between the fuel and walls suppresses premature ignition while still allowing for a mixing efficiency of up to 0.46-0.54. Nomenclature a = speed of sound c = species mass fraction d w = distance from wall to first inner node F pot = thrust potential F pot;ref = reference thrust potential at engine inlet k = turbulence kinetic energy M c = convective Mach number, q 1 q 2 =a 1 a 2 _ m = mass flow rate _ m air;engine = mass flow rate of air in engine p = pressure p ?= effective pressure, p 2=3k Pr t = turbulent Prandtl number q = magnitude of velocity vector r = grid size factor Sc t = turbulent Schmidt number T = temperature x 1 , x 2 , x 3 = Cartesian coordinates y = nondimensional wall distance, d w w p = m = mixing efficiency = viscosity = density w = wall shear stress = equivalence ratio ! = dissipation rate per unit of turbulent kinetic energy Subscripts b = station of interest c = station of interest reversibly expanded to constant pressure at shcramjet exit area Superscripts R = reacting S = stoichiometric

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“…Understanding of oblique detonation in a concentration gradient is lacking. A few researchers discussed effects of non-uniformity, 10,17,18) but their investigations were limited to a few parameters. Objective of our research is then to understand effects of a concentration gradient on structures of oblique detonation and shock-induced combustion (defined as a decoupled shock and flame front) through a parametric numerical study, and to discuss physics involved in their features.…”

Section: Introductionmentioning

confidence: 99%

“…Concentration gradients were introduced into the incoming mixture prescribing them by the Gaussian function. 10,17,18) …”

Section: Introductionmentioning

confidence: 99%

“…[5][6][7] However, since premixing in ODWE is done in a hypersonic flow, it inevitably results in an inhomogeneous mixture. 10) Several researchers have been working on improvement of premixing in ODWE, 11,12) but we also have to consider effects of incomplete premixing on oblique detonation to evaluate possibility of flame stabilization and to resultant performance degradation of ODWE.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Numerical Simulation of Incompletely Premixed Oblique Detonation Stabilized on a Solid Surface

Iwata

Nakaya

Tsue

2016

AEROSPACE TECHNOLOGY JAPAN

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Oblique detonation under incompletely premixed conditions has not been well understood and is of great concern when difficulty of high-speed premixing in Oblique Detonation Wave Engine (ODWE), which is one of the most potential hypersonic aerospace propulsion systems, is taken into account. This study numerically investigated effects of fuel concentration gradients on oblique detonation and shock-induced combustion formed on a 28.20° wedge by solving two-dimensional Navier-Stokes equations with a detailed chemical kinetic mechanism of hydrogen-air combustion. Oblique detonation with smooth-transition formed at a Mach number of 8.00, a static temperature of 300 K, and a static pressure of 8.50 kPa was referred as the completely premixed case. Fuel concentration gradients were described by the Gaussian function. At the maximum equivalence ratio of 2.00, Smooth-transition was replaced by abrupt-transition. When maximum equivalence ratio exceeded 3.00, a V-shaped flame front appeared with its leading edge located away from the wedge, which caused two separate triple-points to be observed. Second triple point appeared at the intersection of the incident shock or the detonation front and a reflected shock generated by compression waves on the lower side of the deflagration front. Increase of the front angle enabled intensive combustion to be maintained downstream of it.

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Incomplete Mixing and Off-Design Effects on Shock-Induced Combustion Ramjet Performance

Cited by 41 publications

References 3 publications

Research status of key techniques for shock-induced combustion ramjet (shcramjet) engine

Research status of key techniques for shock-induced combustion ramjet (shcramjet) engine

Hypervelocity Fuel/Air Mixing in Mixed-Compression Inlets of Shcramjets

Numerical Simulation of Incompletely Premixed Oblique Detonation Stabilized on a Solid Surface

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