Experiments on High Speed Ejectors

Wu, Jiunn-Jenq

doi:10.21236/ada201445

Cited by 2 publications

(2 citation statements)

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“…The majority of practical ejectors operate in this regime and the experimental and theoretical RCS ejector study is directed to this area. The secondsolution with supersonic exit Mach numbers is possible to achieve in practice* 19) , and the theory is discussed at length in Refs 8, 9 and 20. The existence of the second solution and the transition between the first-and second-solution does however impinge on the present study.…”

Section: Ejector Solutionsmentioning

confidence: 99%

The application of high pressure ejectors to reaction control systems

Miller

Seel

1991

Aeronaut. j.

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SummaryA study of the thrust augmentation arising from the application of ejectors to high pressure reaction control systems typical of VSTOL aircraft is presented. A numerical analysis was undertaken to identify parameters critical to the attainment of high performance. A novel technique for improving mixing in confined ejector flows was investigated experimentally.Theoretical work considered configurations with both sonic and supersonic primary flows. The studies show that thrust augmentation ratios ⋍ 1·3 are possible at pressure ratios around 15 using an ejector area ratio of 35. Little benefit accrues from diffusion at high pressure and performance is sensitive to mixing efficiency in terms of the mixing duct exit flow uniformity and primary nozzle losses.Jets issuing from underexpanded nozzles fitted with castellations around their exit were compared experimentally with those leaving plain nozzles. Significant improvements in jet entrainment rates arise from the castellations. Strong correlation is observed between the free jet mixing rate and ejector secondary thrust. The level of thrust augmentation is low in conventional terms but constitutes a significant improvement over plain nozzle ejectors and non-augmented convergent nozzles.

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Section: Ejector Solutionsmentioning

confidence: 99%

The application of high pressure ejectors to reaction control systems

Miller

Seel

1991

Aeronaut. j.

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“…This concept has become particularly popular with the industry for the purposes of vertical takeoff aircraft. Examples of thrust-augmenting ejector topics are well represented in recent literature [5][6][7][8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Analysis of two-phase ejectors with Fabri choking

Lear

Parker

Sherif

2002

Proceedings of the Institution of Mechanical Engineers, Part C:

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A one-dimensional mathematical model was developed using the equations governing the ow and thermodynamics within a jet pump with a mixing region of constant cross-sectional area. The analysis is capable of handling two-phase ows and the resulting ow phenomena such as condensation shocks and the F abri limit on the secondary mass owrate. This work presents a technique for quickly achieving rst-approximation solutions for two-phase ejectors. The thermodynamic state of the working uid, R -134a for this analysis, is determined at key locations within the ejector. F rom these results, performance parameters are calculated and presented for varying inlet conditions. The F abri limit was found to limit the operational regime of the two-phase ejector because, in the two-phase region, the speed of sound may be orders of magnitude smaller than in a single-phase uid. NOTATIONa speed of sound (m/s) A area (m 2 ) C p diffuser pressure recovery coef cient P e 7P i P o, i 7P i h speci c enthalpy (kJ/kg) m m mass owrate (kg/s) M M ach number P absolute pressure (kPa) s speci c entropy (kJ/kg K ) T absolute temperature (K ) V velocity (m/s) x quality r density (kg/m 3 ) F entrainment ratio

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Experiments on High Speed Ejectors

Cited by 2 publications

References 1 publication

The application of high pressure ejectors to reaction control systems

The application of high pressure ejectors to reaction control systems

Analysis of two-phase ejectors with Fabri choking

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