Role of hydrogen/air chemistry in nozzle performance for a hypersonic propulsion system

Sangiovanni, J.J.; Barber, Tracie; Syed, S. A.

doi:10.2514/3.11495

Cited by 29 publications

(14 citation statements)

References 7 publications

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“…5, the ratio was 0⋅956. This is in accord with previous investigations (3)(4)(5)(6)(7) , where nozzle freezing caused only a small loss in thrust.…”

Section: Numerical Modellingsupporting

confidence: 93%

“…An early study (3) of freezing of hydrogen-air chemical recombination in a ramjet thrust nozzle, where the expansion takes place from a low subsonic Mach number, showed that if equilibrium flow is maintained past the low supersonic area ratios the loss in thrust caused by chemical freezing is not exceedingly high. In later numerical studies of scramjet thrust nozzles at high flight Mach numbers, where the nozzle expansion takes place from supersonic Mach numbers, it was shown that although molecular vibration was in equilibrium throughout the nozzle, the chemical composition was not (4) , that at precombustion pressures of the order of an atmosphere there was little recombination in the nozzle (5) and that, in spite of this, the lack of complete recombination yielded an overall thrust which was only 1% less than the value for an equilibrium expansion (6) . Also, a study of thrust loss mechanisms in scramjets (7) showed that nozzle freezing represented only a small fraction of the overall losses.…”

Section: Introductionmentioning

confidence: 99%

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Effects of hydrogen–air non–equilibrium chemistry on the performance of a model scramjet thrust nozzle

et al. 2004

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Two aspects of hydrogen-air non-equilibrium chemistry related to scramjets are nozzle freezing and a process called 'kinetic afterburning' which involves continuation of combustion after expansion in the nozzle. These effects were investigated numerically and experimentally with a model scramjet combustion chamber and thrust nozzle combination. The overall model length was 0⋅5m, while precombustion Mach numbers of 3⋅1±0⋅3 and precombustion temperatures ranging from 740K to 1,400K were involved. Nozzle freezing was investigated at precombustion pressures of 190kPa and higher, and it was found that the nozzle thrusts were within 6% of values obtained from finite rate numerical calculations, which were within 7% of equilibrium calculations. When precombustion pressures of 70kPa or less were used, kinetic afterburning was found to be partly responsible for thrust production, in both the numerical calculations and the experiments. Kinetic afterburning offers a means of extending the operating Mach number range of a fixed geometry scramjet.

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“…5, the ratio was 0⋅956. This is in accord with previous investigations (3)(4)(5)(6)(7) , where nozzle freezing caused only a small loss in thrust.…”

Section: Numerical Modellingsupporting

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Effects of hydrogen–air non–equilibrium chemistry on the performance of a model scramjet thrust nozzle

et al. 2004

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“…Key among these are: the adjustment of the duct and inlet geometry as a function of flight Mach number; mixing of fuel with the air while controlling pre-ignition; conversion of gas chemical energy to kinetic energy within the exhaust nozzle (Harradine et al 1990 andSangiovanni et al 1993). Key among these are: the adjustment of the duct and inlet geometry as a function of flight Mach number; mixing of fuel with the air while controlling pre-ignition; conversion of gas chemical energy to kinetic energy within the exhaust nozzle (Harradine et al 1990 andSangiovanni et al 1993).…”

Section: Reactantsmentioning

confidence: 99%

Combustion in High-Speed Flows

Buckmaster¹,

Jackson²,

Kumar³

1994

ICASE/LaRC Interdisciplinary Series in Science and Engineering

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The focus of the second workshop was directed towards the development, analysis, and application of basic models in high speed propulsion of particular interest to NASA. The exploration of a dual approach combining asymptotic and numerical methods for the analysis of the models was particularly encouraged. The objectives of this workshop were i) the genesis of models that would capture or reflect the basic pllysical phenomena in SCRAMJETs and/or oblique detonation-wave engines (ODWE), and ii) the stimulation of a greater interaction between NASA experimental research community and the academic community.The lead paper by D. Bushnell on the status and issues of high speed propulsion relevant to both the SCRAMJET and the ODWE parallels his keynote address which set the stage of the workshop. Following the lead paper were five technical sessions with titles and chairs: Experiments (C. Rogers), Reacting Free Shear Layers (C. E. Grosch), Detonations (A. K. Kapila), Ignition and Structure (J. Buckmaster), and Unsteady Behaviour ('1'. L. Jackson).The session chairs were responsible for the planning of their session. In each of the sessions formal discussion papers were given by experts followed by a general discussion involving the participants. This volume contains the manuscripts presented in each session. In addition, a panel discussion was held on the last day, chaired by J. Buckmaster. The panel members were

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“…Research on chemical non-equilibrium flow is mostly concentrated in the axisymmetric convergentdivergent nozzle. A computer model for describing quasi-onedimensional flow was used by Sangiovanni [1] to study the role of hydrogen/air chemistry in nozzle performance for a hypersonic propulsion system. The study shows that finite-rate chemistry should not be neglected in nozzle performance simulations because beneficial chemical processes persist throughout the entire nozzle length.…”

Section: Introductionmentioning

confidence: 99%

Numerical Study of Chemical Non-equilibrium Flow in Hydrocarbon Scramjet Nozzle

Zhang¹,

Li-zi²,

Yu³

2012

Proceedings of the 1st International Conference on Mechanical Engineering and Material Science

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The non-equilibrium flow and frozen flow of hydrocarbon scramjet nozzle were numerically simulated to research the non-equilibrium effects on the nozzle performance. The numerical results show the recombination occurs during the expansion in the scramjet nozzle, which is helpful to the nozzle performance. The calculation results suggest the influence of the inlet mach and the fuel equivalence ratio to the non-equilibrium effects on nozzle performance is visible.

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Role of hydrogen/air chemistry in nozzle performance for a hypersonic propulsion system

Cited by 29 publications

References 7 publications

Effects of hydrogen–air non–equilibrium chemistry on the performance of a model scramjet thrust nozzle

Effects of hydrogen–air non–equilibrium chemistry on the performance of a model scramjet thrust nozzle

Combustion in High-Speed Flows

Numerical Study of Chemical Non-equilibrium Flow in Hydrocarbon Scramjet Nozzle

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