Experimental Investigation of Nozzle Orientation Effects on Mixing Characteristics of Elliptic Triple Free Jets

Morris, Ella M.; Aleyasin, Seyed Sobhan; Biswas, Neelakash; Tachie, Mark F.

doi:10.1115/ajkfluids2019-5463

“…Different PC values for Single Ellipse Major and Single Ellipse Minor could result from separate simulations of elliptical jet with orientation, which could lead to a numerical discrepancy of results. Similar results for the elliptical jet with orientation are reported by Morris et al 16,30 The potential core length of the elliptical jets is 8.6% shorter than that of the single circular jet. These results agree with Mi and Nathan et al 3 for the elliptical nozzle case.…”

Section: Resultssupporting

confidence: 89%

“…It is also noted that the difference between the decay rates of Twin Ellipse Major and Twin Ellipse Minor is not very drastic, so it can be concluded that the orientation did not affect the velocity decay rate significantly. Similar observations were made by Mi and Nathan 3 and Morris et al 30 in their studies.…”

Section: Mean Velocity Decay Ratesupporting

confidence: 87%

See 1 more Smart Citation

The effects of spacing to diameter ratio on mixing characteristics of circular and elliptical twin jets

Kumar

¹

,

Sinhamahapatra

²

2023

Proceedings of the Institution of Mechanical Engineers, Part G:

2

0

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Twin jets are encountered in many engineering and industrial applications, such as aircraft propulsion systems and combustors. Twin jets create a flow field that is more complex than a single jet due to its interaction with the individual jets. This paper investigates the effects of spacing to diameter ( S/ D e) ratio and orientation on the mixing properties of circular and elliptical twin jets at four different S/ D e ratios of 1.25, 1.50, 1.75, and 2.0, respectively. The numerical simulations of twin jets are carried out with a jet Mach number of 0.8 using the Shear Stress Transport ( SST) K- ω turbulence model. The results show that near the orifice exit, the twin jets are issuing into ambient conditions separately and resemble a free jet, leading to a potential core length independent of S/ D e. The merging and combined point locations change linearly from the exit with an increasing S/ D e ratio. The decay rate is higher for Twin Ellipse Minor than those in Twin Circle and Twin Ellipse Major, verified by a shorter converging region. In addition, near the jet exit, the spread rate is higher for Twin Ellipse Minor, which is consistent with the closer merging point location. The jet mixing is superior for twin minor elliptical configuration compared to twin circle and twin major elliptical jets at all S/ D e ratios.

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“…More atypical solutions in this regard have also been presented, e.g. for an elliptical nozzle [33], [34] or a lobed nozzle [35], [36]. The diffuser shape also affects the number of symmetry axes that can be distinguished in a jet.…”

Section: Introductionmentioning

confidence: 99%

Pressure Distribution On A Flat Plate In The Context of The Phenomenon of The Coanda Effect Hysteresis

Skotnicka-Siepsiak

¹

2021

Preprint

0

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As a result of the Coanda effect, a symmetrical free jet will flow as an asymmetrical wall jet. At the same time, at the obstacle along which the flow is observed, the wall jet generates pressure distribution. In this study, the obstacle located at the diffuser outlet is a flat plate with a variable inclination angle. The article presents results of the study on pressure distributions on a flat plate with a variable angle of inclination. What is new, however, is that the presented results of the experimental research include the influence of the Coanda effect hysteresis on the pressure distribution on the plate. The article shows how pressure distributions change on the plate depending on whether the initial angle of inclination was 0 degree and was increased gradually in the course of the experiment until a detachment of the jet flowing from the plate was observed, or the initial angle of inclination was close to 90 degrees in the primal state and as the angle of the plate inclination was decreased, the jet flowing towards the plate reached the state of attachment to the plate surface.

show abstract

Pressure distribution on a flat plate in the context of the phenomenon of the Coanda effect hysteresis

Skotnicka-Siepsiak

¹

2022

Sci Rep

3

0

View full text Add to dashboard Cite

As a result of the Coanda effect, a symmetrical free jet will flow as an asymmetrical wall jet. At the same time, at the obstacle along which the flow is observed, the wall jet generates pressure distribution. In this study, the obstacle located at the diffuser outlet is a flat plate with a variable inclination angle. The article presents results of the study on pressure distributions on a flat plate with a variable angle of inclination. In the experiment, the Reynolds number ranged from 16,192 to 42,240. A fixed geometry diffuser (Witoszyński nozzle) with a height of 0.60 m, width of 0.02 m and outlet velocity of 11.33–29.57 m/s was used. A plate with a length of 1.00 m and a variable inclination angle was installed at the diffuser outlet. What is new, however, is that the presented results of the experimental research include the influence of the Coanda effect hysteresis on the pressure distribution on the plate. The article shows how pressure distributions change on the plate depending on whether the initial angle of inclination was 0° and was increased gradually in the course of the experiment until a detachment of the jet flowing from the plate was observed, or the initial angle of inclination was close to 90° in the primal state and as the angle of the plate inclination was decreased, the jet flowing towards the plate reached the state of attachment to the plate surface. The study demonstrated that for a turbulent jet, pressure distribution on a flat plate is determined not only by the plate’s inclination angle, but also by the direction of its rotation.

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Experimental Investigation of Nozzle Orientation Effects on Mixing Characteristics of Elliptic Triple Free Jets

Cited by 3 publications

References 0 publications

The effects of spacing to diameter ratio on mixing characteristics of circular and elliptical twin jets

The effects of spacing to diameter ratio on mixing characteristics of circular and elliptical twin jets

Pressure Distribution On A Flat Plate In The Context of The Phenomenon of The Coanda Effect Hysteresis

Pressure distribution on a flat plate in the context of the phenomenon of the Coanda effect hysteresis

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