Comparative study on interfacial oscillations of rectangular and elliptical liquid jets
17 Jan 2020-Vol. 234, Iss: 7, pp 1272-1286
TL;DR: The instability characteristics and flow structures of water jets injected from rectangular and elliptical nozzles with aspect ratios varying from 2 to 6 were experimentally studied and compared as mentioned in this paper, and the results showed that the instability properties and flow structure of the water jets were similar to those of the conventional water jets.
Abstract: The instability characteristics and flow structures of water jets injected from rectangular and elliptical nozzles with aspect ratios varying from 2 to 6 were experimentally studied and compared. S...
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Book•
01 Dec 1988
TL;DR: In this paper, the basic processes in Atomization are discussed, and the drop size distributions of sprays are discussed.Preface 1.General Considerations 2.Basic Processes of Atomization 3.Drop Size Distributions of Sprays 4.Atomizers 5.Flow in Atomizers 6.AtOMizer Performance 7.External Spray Charcteristics 8.Drop Evaporation 9.Drop Sizing Methods Index
Abstract: Preface 1.General Considerations 2.Basic Processes in Atomization 3.Drop Size Distributions of Sprays 4.Atomizers 5.Flow in Atomizers 6.Atomizer Performance 7.External Spray Charcteristics 8.Drop Evaporation 9.Drop Sizing Methods Index
1,214 citations
TL;DR: Flow dynamics of two-dimensional liquid sheets discharged into low-speed gaseous crossflow were experimentally investigated and revealed that the liquid sheets represented a unique concave-like structure that was named as inflated sheet.
Abstract: Flow dynamics of two-dimensional liquid sheets discharged into low-speed gaseous crossflow were experimentally investigated. The flow characteristics of liquid sheets were visualized by taking advantage of diffused backlight shadowgraphy and high-speed photography. Three injectors with an equal thickness of 0.35 mm and aspect ratios of 30, 60 and 90 were manufactured and tested at different flow conditions. A full discussion about the flow characteristics of two-dimensional liquid sheets in the presence of transverse airflow is provided. Visualizations revealed that the liquid sheets represented a unique concave-like structure that was named as inflated sheet. This special characteristic was not previously seen on any other circular or non-circular liquid jets and therefore made the flow dynamics of liquid sheets in subsonic crossflow very distinguished. The inflated sheet was found to transform from an enclosed structure into an open structure. The open inflated sheet was disturbed by different breakup mechanisms including sheet rupture, bag breakup, and Rayleigh–Taylor instability. Based on the observed phenomena, the flow was grouped into five regimes including biconvex, enclosed inflated sheet, open inflated sheet, bag breakup/sheet rupture, and multimode breakup. Furthermore, it was found that the droplet region was bifurcated due to the different breakup mechanisms acting simultaneously upon the sheet. Measurements of sheet trajectory were performed and the effects of momentum ratio and Weber number were studied. It was found that Weber number was only effective at low values, while momentum ratio remarkably impacted the trajectory.
11 citations
TL;DR: In this paper, a two-dimensional liquid sheet injected transversely into a subsonic airstream was comprehensively investigated and the main features of the liquid sheet in crossflow were identified.
8 citations
TL;DR: In this paper, the breakup characteristics of micro rectangular jets with external disturbances were experimentally investigated and it was shown that the ejected rectangular jet experienced three stages from the nozzle to the downstream locations, namely, the axis-switching rectangular jet, the disturbance induced jet fluctuation, and the structured droplet train after the breakup.
6 citations
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3 citations
References
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Book•
01 Feb 1968
TL;DR: In this paper, a collection of mathematical formulas and numerical tables is presented.They cover elementary concepts in algebra, geometry and more advanced concepts in differential equations and vector analysis, including algebraic, geometry, and differential equations.
Abstract: Supplying a collection of mathematical formulas and numerical tables, this text covers elementary concepts in algebra, geometry and more advanced concepts in differential equations and vector analysis.
1,277 citations
Book•
01 Dec 1988
TL;DR: In this paper, the basic processes in Atomization are discussed, and the drop size distributions of sprays are discussed.Preface 1.General Considerations 2.Basic Processes of Atomization 3.Drop Size Distributions of Sprays 4.Atomizers 5.Flow in Atomizers 6.AtOMizer Performance 7.External Spray Charcteristics 8.Drop Evaporation 9.Drop Sizing Methods Index
Abstract: Preface 1.General Considerations 2.Basic Processes in Atomization 3.Drop Size Distributions of Sprays 4.Atomizers 5.Flow in Atomizers 6.Atomizer Performance 7.External Spray Charcteristics 8.Drop Evaporation 9.Drop Sizing Methods Index
1,214 citations
"Comparative study on interfacial os..." refers background in this paper
...The main goals of this study can be summarized as follows: (1) surveying the similarities and dissimilarities of flow development of both rectangular and elliptical jets by the aid of visualizations, (2) investigating the effect of aspect ratio, and (3) measuring and comparing the axis-switching parameters of both jets, including wavelength, frequency, and amplitude....
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TL;DR: Noncircular jets have been identified as an efficient technique of passive flow control that allows significant improvements of performance in various practical systems at a relatively low cost because noncircular jet rely solely on changes in the geometry of the nozzle as discussed by the authors.
Abstract: Noncircular jets have been the topic of extensive research in the last fifteen years. These jets were identified as an efficient technique of passive flow control that allows significant improvements of performance in various practical systems at a relatively low cost because noncircular jets rely solely on changes in the geometry of the nozzle. The applications of noncircular jets discussed in this review include improved large- and small-scale mixing in low- and high-speed flows, and enhanced combustor performance, by improving combustion efficiency, reducing combustion instabilities and undesired emissions. Additional applications include noise suppression, heat transfer, and thrust vector control (TVC). The flow patterns associated with noncircular jets involve mechanisms of vortex evolution and interaction, flow instabilities, and fine-scale turbulence augmentation. Stability theory identified the effects of initial momentum thickness distribution, aspect ratio, and radius of curvature on the initial flow evolution. Experiments revealed complex vortex evolution and interaction related to selfinduction and interaction between azimuthal and axial vortices, which lead to axis switching in the mean flow field. Numerical simulations described the details and clarified mechanisms of vorticity dynamics and effects of heat release and reaction on noncircular jet behavior.
537 citations
"Comparative study on interfacial os..." refers background in this paper
...The main goals of this study can be summarized as follows: (1) surveying the similarities and dissimilarities of flow development of both rectangular and elliptical jets by the aid of visualizations, (2) investigating the effect of aspect ratio, and (3) measuring and comparing the axis-switching parameters of both jets, including wavelength, frequency, and amplitude....
[...]
85 citations
"Comparative study on interfacial os..." refers background or methods in this paper
...In this figure, photos of RC(2) and RC(6) jets are compared at the same jet velocity of 0....
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...The main goals of this study can be summarized as follows: (1) surveying the similarities and dissimilarities of flow development of both rectangular and elliptical jets by the aid of visualizations, (2) investigating the effect of aspect ratio, and (3) measuring and comparing the axis-switching parameters of both jets, including wavelength, frequency, and amplitude....
[...]
...Similar to Weber number, E(2) jet owns the largest Reynolds number in comparison with other nozzles which means that it enters the transitional and turbulent regimes at lower mass flow rates....
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...Because of the differences in hydraulic diameter of nozzles, Weber number is not the same for all nozzles at equal mass flow rates, and according to Figure 7, the highest value belongs to the E(2) jet, while the lowest value is obtained for the RC(6) jet....
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...Evolution of axis-switching establishment with Weber number for E(2) jet....
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TL;DR: In this paper, an experimental study on liquid jets discharging from elliptical orifices into still ambient air is presented, where the effects of the orifice aspect ratio and liquid viscosity on the axis-switching process are revealed through this study.
74 citations