Thickness Variation of a Liquid Sheet Formed by Two Impinging Jets Using Holographic Interferometry

1998 ◽  
Vol 120 (3) ◽  
pp. 482-487 ◽  
Author(s):  
Y.-B. Shen ◽  
D. Poulikakos
Keyword(s):  
Holographic Interferometry ◽  
Thickness Distribution ◽  
Azimuthal Angle ◽  
Radial Distance ◽  
Sheet Thickness ◽  
Impinging Jets ◽  
Liquid Sheet ◽  
Liquid Jets ◽  
Thickness Variation ◽  
Proportionality Constant

In the work presented in this paper a real time holographic interferometry technique is developed to measure instantaneously and nonintrusively the thickness distribution of a liquid sheet formed by the impingement of two liquid jets. The experimental results are compared with earlier largely unverified analytical predictions. It is shown that the assumption that the sheet thickness is inversely proportional to the radial distance from the impingement point is in principle good. The dependence of the theoretically obtained proportionality constant on the azimuthal angle, however, while exhibiting the same trend it also shows some quantitative differences. Reasons are given in the context of the work. In addition, a weak effect of the jet velocity on the proportionality constant is found to exist. In the theories no such effect was modeled. Finally, comparisons between theoretical and experimental isothickness contours show differences. Overall, there appears to be a justification for improved theoretical studies including effects such as that of gravitation.

Detailed Numerical Simulation of Two Impinging Jets With Moderate Injection Velocities

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.

Study on some Aspects of Breakup Characteristics of Power-Law Fluid with Impinging Jets Based on Mechanics Properties

2012 ◽  
Vol 625 ◽  
pp. 57-60
Author(s):  
En Dong Wang ◽  
Yan Yin ◽  
Qing Du
Keyword(s):  
Power Law ◽  
High Speed ◽  
Wave Length ◽  
Impinging Jets ◽  
Liquid Sheet ◽  
Liquid Jets ◽  
Power Law Fluid ◽  
Round Jets ◽  
Breakup Length ◽  
Jet Velocity

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.

scholarly journals Investigation of Thickness Distribution Variation in Deep Drawing of Conical Steel Products

2021 ◽  
Vol 39 (4A) ◽  
pp. 586-598
Author(s):  
Muhsin J. Jweeg ◽  
Adnan I. Mohammed ◽  
Mohammed S. Jabbar
Keyword(s):  
Sheet Metal ◽  
Deep Drawing ◽  
Thickness Distribution ◽  
Sheet Thickness ◽  
Galvanized Steel ◽  
Thickness Variation ◽  
Low Carbon ◽  
Nose Radius ◽  
Numerical Work ◽  
Punch Velocity

This study investigates the thickness variation behavior of deep drawing conical products under the effect of different forming parameters such as die wall inclination angle, punch velocity, sheet thickness, and sheet metal type. Two types of sheet metal were used, low carbon (AISI 1008) and galvanized steel sheets, of 110 mm diameters circular blanks at 0.9 and 1.2mm thickness formed by tooling set (punch, die, and blank holder). The conical dies inclination angles were at 70ᵒ, 72ᵒ, and 74ᵒ where, the punch velocity was 100, 150, and 200 mm/min. Numerical simulation was conducted using ABAQUS 6.14 where a dynamic explicit solver was used to perform forming of conical products. The results show that maximum thinning occurs at punch nose radius region and maximum thickening in sidewall region and thinning are increased with the increasing of die sidewall angle and sheet thickness. In regard to sheet type, the Lankford coefficients r-value shows a great role in thinning behavior with respect to rolling (r-values direction). The results have shown a good agreement between experimental and numerical work with a maximum discrepancy of 5%.

Characteristics of Sheet Formed by Collision of Two Elliptical Jets at Short Impact Distance

2016 ◽  
Vol 138 (5) ◽  
Author(s):  
Fei Zhao ◽  
Li-jun Yang ◽  
Chao-jie Mo ◽  
Xue-de Li
Keyword(s):  
Axial Ratio ◽  
Impinging Jets ◽  
Liquid Sheet ◽  
Force Balance ◽  
Liquid Jets ◽  
Balance Equations ◽  
Oblique Collision ◽  
Circular Jets ◽  
Good Agreement ◽  
Impact Distance

The research on characteristics of impinging jet has a long history and focuses mainly on the circular jets, whereas the impingement of noncircular jets, such as elliptical jets, receives much less attention. This paper investigated liquid sheet resulting from the oblique collision of two elliptical jets at short impact distance. The elliptical liquid jets contract and collide obliquely at impact point, forming a sheet in the form of a leaf bounded by a thicker rim. An improved theoretical model, taking jet contraction into account, for two elliptical impinging jets is established. The sheet features are obtained by combining the conservation equations between the liquid jet and sheet with the force balance equations of the sheet rim. The calculated sheet shapes are compared with the experiments, and the results show good agreement. The experimental results also indicate that the liquid sheet formed by elliptical jets tends to be larger and more unstable than that formed by circular jets. Based on the model, the effects of axial ratio and impact distance on the sheet characteristics, such as sheet shape and thickness, are also studied.

Dynamic Measurement of Liquid Sheet Formed by Impinging Jets via Partial Coherent Interferometry

2018 ◽  
Author(s):  
Weixiao Shang ◽  
Jun Chen
Keyword(s):  
Thickness Distribution ◽  
Theoretical Models ◽  
Impinging Jets ◽  
Liquid Sheet ◽  
Partial Coherence ◽  
Experimental Conditions ◽  
Coherence Property ◽  
Liquid Sheets ◽  
Degree Of Coherence ◽  
Optical Paths

In this work, the thicknesses of impinging liquid sheets formed by two alike impinging jets with different flow rates are investigated via a non-intrusive measurement technique, the Partial Coherent Interferometry. The Reynolds number and Weber number are 720 to 780 and 120 to 150, respectively. An interferometer with the calibrated partial coherence property is used to record the interference pattern by passing one branch of the two optical paths through the impinging sheet. By examining the phase and the degree of coherence of the pattern, the absolute thickness distribution of the impinging sheet is measured. The thicknesses with different experimental conditions are compared to the previous theoretical models and the influences of the flow rate and impinging angle are concluded.

HOLOGRAPHY EXPERIMENTS IN THE BREAKUP REGION OF A LIQUID SHEET FORMED BY TWO IMPINGING JETS

1995 ◽  
Vol 5 (4-5) ◽  
pp. 387-402 ◽  
Author(s):  
B. S. Kang ◽  
Y. B. Shen ◽  
D. Poulikakos
Keyword(s):  
Impinging Jets ◽  
Liquid Sheet

scholarly journals Effect of Tool Geometry Parameters on the Formability of a Camera Cover in the Deep Drawing Process

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3993
Author(s):  
Thanh Trung Do ◽  
Pham Son Minh ◽  
Nhan Le
Keyword(s):  
Deep Drawing ◽  
Thickness Distribution ◽  
Metal Flow ◽  
Sheet Thickness ◽  
Side Wall ◽  
Tool Geometry ◽  
Drawing Process ◽  
Nose Radius ◽  
Deep Drawing Process

The formability of the drawn part in the deep drawing process depends not only on the material properties, but also on the equipment used, metal flow control and tool parameters. The most common defects can be the thickening, stretching and splitting. However, the optimization of tools including the die and punch parameters leads to a reduction of the defects and improves the quality of the products. In this paper, the formability of the camera cover by aluminum alloy A1050 in the deep drawing process was examined relating to the tool geometry parameters based on numerical and experimental analyses. The results showed that the thickness was the smallest and the stress was the highest at one of the bottom corners where the biaxial stretching was the predominant mode of deformation. The problems of the thickening at the flange area, the stretching at the side wall and the splitting at the bottom corners could be prevented when the tool parameters were optimized that related to the thickness and stress. It was clear that the optimal thickness distribution of the camera cover was obtained by the design of tools with the best values—with the die edge radius 10 times, the pocket radius on the bottom of the die 5 times, and the punch nose radius 2.5 times the sheet thickness. Additionally, the quality of the camera cover was improved with a maximum thinning of 25% experimentally, and it was within the suggested maximum allowable thickness reduction of 45% for various industrial applications after optimizing the tool geometry parameters in the deep drawing process.

Controlling the Thickness Uniformity in Equal Channel Angular Rolling (ECAR)

2007 ◽  
Vol 539-543 ◽  
pp. 2872-2877 ◽  
Author(s):  
Young Hoon Chung ◽  
Jong Woo Park ◽  
Kyong Hwan Lee
Keyword(s):  
Shear Strain ◽  
Shear Deformation ◽  
Control Mechanism ◽  
Sheet Thickness ◽  
Surface Friction ◽  
Metal Sheet ◽  
Thickness Variation ◽  
Thickness Control ◽  
Thickness Uniformity ◽  
Elastic Unit

As the surface friction between feeding rolls and metal sheet generates the feeding power of ECAR, the generated feeding power is low, and the friction between the metal sheet and ECAR die should be minimized. However, for obtaining a large shear deformation by ECAR, the metal sheet should be tightly contacted with the wall of ECAR die. In this condition, the thickness of the metal sheet is continuously increased during ECAR. A new ECAR apparatus is developed for maximizing the shear deformation and obtaining sheet thickness uniformity, and succeeding continuous ECAR with such a limited feeding power. By controlling the outlet gap of the ECAR die with elastic unit, the thickness of the metal sheet is kept uniform. Detailed thickness control mechanism during the new ECAR process is analyzed. A sheet of Al 6063 alloy that is 1-pass deformed with the new ECAR apparatus shows below ±0.037 mm of thickness variation and 0.61 of shear strain.

Consistent Theoretical Model of Mean Diameter and Size Distribution by Liquid Sheet Atomization

2012 ◽  
Author(s):  
Chihiro Inoue ◽  
Toshinori Watanabe ◽  
Takehiro Himeno ◽  
Seiji Uzawa ◽  
Mitsuo Koshi
Keyword(s):  
Theoretical Model ◽  
Kinetic Energy ◽  
Droplet Diameter ◽  
Velocity Profiles ◽  
Liquid Sheet ◽  
Estimation Methods ◽  
Liquid Jets ◽  
Injection Velocity ◽  
Size Distributions ◽  
Mean Diameter

A consistent theoretical model is proposed and validated for calculating droplet diameters and size distributions. The model is derived based on the energy conservation law including the surface free energy and the Laplace pressure. Under several hypotheses, the law derives an equation indicating that atomization results from kinetic energy loss. Thus, once the amount of loss is determined, the droplet diameter is able to be calculated without the use of experimental parameters. When the effects of ambient gas are negligible, injection velocity profiles of liquid jets are the essential cause of the reduction of kinetic energy. The minimum Sauter mean diameter produced by liquid sheet atomization is inversely proportional to the injection Weber number when the injection velocity profiles are laminar or turbulent. A non-dimensional distribution function is also derived from the mean diameter model and Nukiyama-Tanasawa’s function. The new estimation methods are favorably validated by comparing with corresponding mean diameters and the size distributions, which are experimentally measured under atmospheric pressure.

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