Improved methods of characterizing ejector pumping performance

Der, J.

doi:10.2514/3.23342

Cited by 14 publications

(4 citation statements)

References 2 publications

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“…Therefore, the ejector performance and its noise characteristics are dependent on the turbulent mixing which takes place in a free shear layer originating from the end of the separation between the primary and secondary flows. 6 As studied by Der 6 in detail and shown in Figure 1, the ejector performance in general, can be deduced from the behavior of the associated shear layer and its relation to the ejector shroud walls. For instance, if the mixing duct length (L) is too small, the shear layer will not attach to the shroud wall, leaving the secondary flow open to a stronger influence from external conditions and susceptible to separation and recirculation.…”

Section: Ejector Nozzle Exhaust Systemmentioning

confidence: 99%

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Experimental Investigation and Computation of a Supersonic Ejector Nozzle with Clamshells

Thirumurthy

Jones

Blaisdell

et al. 2010

40th Fluid Dynamics Conference and Exhibit

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A new supersonic ejector nozzle with clamshell doors is proposed as a noise suppression jet engine exhaust system. A design table driven, parametric nozzle geometry was designed. The experimental and numerical studies of its flow field were carried out. Cases with and without clamshells were considered and their mean velocity flow fields were compared. The experimental investigation involved the testing of the nozzle in a wind tunnel and the measurements were taken using a seven-hole probe, mounted on an automated 2-axis traverse instrument. Various flow visualization techniques such as the fluorescent oil flow, surface sediment traces, smoke wand and surface tuft were also implemented to capture the flow physics on the inside of the clamshells. Numerical simulations were performed using the commercially available finite volume-based computational fluid dynamic code FLUENT. The computational results are in good agreement with the experimental measurements at different axial locations downstream of the nozzle throat. A zone of flow separation and recirculation is captured at the inner surface of the clamshells in both the experimental investigation and numerical computation.

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Section: Ejector Nozzle Exhaust Systemmentioning

confidence: 99%

“…Attachment of the free mixing layer with the primary nozzle results in an optimum ejector nozzle performance 6. L/∆ parameter defines the performance of the ejector nozzle.…”

mentioning

confidence: 99%

Experimental Investigation and Computation of a Supersonic Ejector Nozzle with Clamshells

Thirumurthy

Jones

Blaisdell

et al. 2010

40th Fluid Dynamics Conference and Exhibit

View full text Add to dashboard Cite

show abstract

“…In ejector nozzles, the dynamic mixing of fluids is the primary mode of momentum transfer [13,14]. The degree of mixing between these two streams of fluid occurs in the free shear layer [15] and determines the performance of the ejector nozzle.…”

Section: Introductionmentioning

confidence: 99%

Optimal Design of Ejector Nozzle Profile with Internal and External Integrated Flow

He,

Shi,

2024

Aerospace

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Based on the orthogonal experimental method, a simulation case of the flow field of the ejector nozzle was designed to investigate the influence of the structural parameters of the ejector nozzle on the internal and external flow. This study explored the effects of throat area, outlet area, throat position, and ejector nozzle length on the ejector flow rate ratio, thrust coefficient, and net thrust coefficient. Subsequently, flow path geometry optimization was conducted to maximize the thrust coefficient or net thrust coefficient. The results revealed that the throat area ratio and the outlet area of the ejector nozzle are the primary factors affecting the aerodynamic performance. Compared to the baseline ejector nozzle model, the optimal model for thrust coefficient exhibited a 16.333% improvement, while the optimal model for net thrust coefficient demonstrated a significant enhancement of 46.674%.

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“…Injector nozzle in aircraft pumps surrounding air by high exhaust velocity flow to reduce infrared radiation，suppress noise and increase thrust. Lamb M and He [1,2] presented simulating ejector nozzle flow field methods in 1990s. Recently, foreign researchers [3,4] investigated different ejector nozzles to suppress noise and find ways to simulate them, the calculation results were in good agreement with experiments.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation on Effects of Variable Specific Heat Ratio on Floating Ejector Nozzle

Zhou

Wang

2014

AMM

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The codes for ejector nozzle with floating external adjustment sheet were specially developed, the flow field was numerically simulated by using parametric modeling method and grid partitioning technique. Turbulence model was selected according to predictions of explicit algebraic Reynolds stress, specific heat ratio (γ) was based on local temperature and gas compositions. The formulas of ideal nozzle parameters were derived using varied γ, which were used to analyze nozzle aerodynamic performance. The results obtained from constant and variable γ were compared. The results show that: nozzle mass flow rate is reduced because of more difficulty in airflow expansion, while nozzle thrust has a tiny change in variable γ cases. Moreover, the high temperature region of inner nozzle is larger and injected cold air is less despite of a smaller balanced floating sheet angle, which are detrimental to thermal protection.

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Improved methods of characterizing ejector pumping performance

Cited by 14 publications

References 2 publications

Experimental Investigation and Computation of a Supersonic Ejector Nozzle with Clamshells

Experimental Investigation and Computation of a Supersonic Ejector Nozzle with Clamshells

Optimal Design of Ejector Nozzle Profile with Internal and External Integrated Flow

Numerical Simulation on Effects of Variable Specific Heat Ratio on Floating Ejector Nozzle

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