Liquid sheet characteristics of two impinging jets with different diameters

Shear-thinning power-law fluid is a kind of non-Newtonian fluid in which the viscosity is a function of shear rate. Impinging jets system is used to study the breakup characteristics of power-law liquid sheets formed by two symmetrical round jets in this study. High quality images are obtained from the experiment with a high speed camera and breakup length is extracted from the images. Closed-rim sheet, web-like sheet and ligaments sheet are observed with the increase of jet velocity. A series of images show that the wave length on the surface of sheets tends to decline as the jet velocity increases. At a low We number, the breakup length increases with an increasing We number. However, it first increases and then decreases when the liquid sheet breaks up at a high We number. The liquid jets with larger diameter collide to each other and lead to a liquid sheet with a smaller breakup length.

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A non-linear model for impinging jets atomization

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1243/09544062jmes710 ◽

2008 ◽

Vol 222 (2) ◽

pp. 213-224 ◽

Cited By ~ 5

Author(s):

E A Ibrahim ◽

B E Outland

Keyword(s):

Linear Model ◽

Weber Number ◽

Drop Size ◽

Impinging Jets ◽

Liquid Sheet ◽

Linear Perturbation ◽

Breakup Length ◽

Half Wavelength ◽

Non Linear ◽

Sheet Breakup

The problem considered is predicting the characteristics of the spray produced by atomization of an attenuating liquid sheet formed by the impingement of two liquid jets of equal diameters and momenta. A second-order non-linear perturbation analysis is employed to model the evolution of harmonic instability waves that lead to sheet distortion and fragmentation. The onset of atomization occurs when the uneven surface modulations of the thinning sheet bring its upper and lower interfaces in contact. It is found that the sheet is torn into ligaments at each half wavelength. The instability of the ligaments causes their eventual disintegration into drops. The results indicate that sheet breakup length, time, and resultant drop size decrease as Weber number is increased. A higher Weber number induces a greater sheet breakup thickness. The breakup length, thickness, time, and drop size are diminished at larger impingement angles. The theoretical predictions of the present non-linear model are in good agreement with available experimental data and empirical correlations for sheet breakup length and drop size.

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The velocity distribution of the liquid sheet formed by two low-speed impinging jets

Physics of Fluids ◽

10.1063/1.1429250 ◽

2002 ◽

Vol 14 (2) ◽

pp. 622-627 ◽

Cited By ~ 37

Author(s):

Y.-J. Choo ◽

B.-S. Kang

Keyword(s):

Velocity Distribution ◽

Impinging Jets ◽

Liquid Sheet ◽

Low Speed

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Spray Characteristics of Elliptical Power-Law Fluid-Impinging Jets

Journal of Fluids Engineering ◽

10.1115/1.4036164 ◽

2017 ◽

Vol 139 (7) ◽

Cited By ~ 3

Author(s):

Fei Zhao ◽

Li-Zi Qin ◽

Qing-Fei Fu ◽

Chao-Jie Mo ◽

Li-Jun Yang

Keyword(s):

Power Law ◽

Impinging Jets ◽

Liquid Sheet ◽

Rheological Parameters ◽

Power Law Fluid ◽

Spray Characteristics ◽

Theoretical Predictions ◽

Fluid Jets ◽

Atomization Efficiency ◽

Improved Model

The spray characteristics of a liquid sheet contribute much to the investigation of atomization efficiency. Considering the jet contracting effect of elliptical jets, an improved model of elliptical power-law fluid jets is proposed herein to derive the spray characteristics. Some experiments have been conducted to verify its feasibility, and the results show a good agreement with theoretical predictions. The effect of the aspect ratio on sheet shape and thickness has been studied to interpret the phenomenon that liquid sheets formed by the impinging elliptical jets are more likely to disintegrate. The relationships between rheological parameters (K and n) and the spray features are also discussed.

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Numerical Simulation of Like and Unlike Impinging Jets

Proceedings ILASS–Europe 2017. 28th Conference on Liquid Atomization and Spray Systems ◽

10.4995/ilass2017.2017.4865 ◽

2017 ◽

Author(s):

Azadeh Kebriaee ◽

Hamed Dolatkhahi ◽

Ghader Oliaee

Keyword(s):

Numerical Simulation ◽

Adaptive Mesh Refinement ◽

Adaptive Mesh ◽

Impinging Jets ◽

Liquid Sheet ◽

Impact Behavior ◽

Injection Speed ◽

Two Fluids ◽

Fluid Jets ◽

The Impact

In the present study, using the open source OpenFOAM code, a numerical simulation is performed taking the adaptive mesh refinement (AMR) technique during solution. Formation of liquid sheet after the impact of two identical cylindrical jets at various conditions is studied. Since the flow pattern depends upon the Reynolds and Weber numbers, numerical tests are conducted at a variety of flow velocities and Reynolds numbers to demonstrate the effect of these parameters on the sheet formation. It is then concluded that at various conditions, different instabilities occur in the flow; hence, different sheet formations a flow patterns happen.In this study, impact of two dissimilar cylindrical fluid jets is successfully simulated for the first time in literature. Actually, water and oil jets are taken into account and their impact behavior is studied. In the presence of the surrounding air, an unstable sheet will form after impact due to the high injection speed of the jets. As depicted in the results, since the inertia and other physical characteristics of the two fluids are dissimilar, different phases are more intensely diffused.DOI: http://dx.doi.org/10.4995/ILASS2017.2017.4865

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Detailed Numerical Simulation of Two Impinging Jets With Moderate Injection Velocities

Volume 5: Multiphase Flow ◽

10.1115/ajkfluids2019-5221 ◽

2019 ◽

Author(s):

Yue Ling ◽

Weixiao Shang ◽

Jun Chen

Keyword(s):

Thickness Distribution ◽

Sheet Thickness ◽

Impinging Jets ◽

Liquid Sheet ◽

Liquid Jets ◽

Rocket Engines ◽

Flow Solver ◽

Plane Normal ◽

Jet Injectors ◽

Propellant Rocket

Abstract Impinging-jet injectors are commonly used in liquid propellant rocket engines. Two cylindrical liquid jets impinge at a certain angle and form a liquid sheet in the plane normal to the jets. When the Reynolds and Weber numbers are large, the liquid sheet becomes unstable and disintegrates into liquid ligaments and droplets. In the present study, we focus on cases with moderate injection velocities so that the liquid sheet remains unbroken. Detailed numerical simulations are performed using the adaptive multiphase flow solver, Basilisk. The volume-of-fluid method is used to resolve the gas-liquid interface. Grid-refinement studies are conducted to verify the formation of the liquid sheet is accurately captured in simulation. The numerical results are compared to the recent experimental measurement of the sheet thickness distribution by partial coherent interferometry and a good agreement is achieved.

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