Theoretical analysis of hydraulic jump on extremely small size liquid jet impingement

1998 ◽  
Vol 7 (3) ◽  
pp. 176-180
Author(s):  
Dingwei Zhou ◽  
Chongfang Ma ◽  
Yutao Ren
Keyword(s):  
Theoretical Analysis ◽  
Hydraulic Jump ◽  
Jet Impingement ◽  
Liquid Jet

Hydraulic Jump due to Jet Impingement on Micro-Patterned Surfaces Exhibiting Ribs and Cavities

2012 ◽  
Author(s):  
M. Johnson ◽  
D. Maynes ◽  
J. C. Vanderhoff ◽  
B. W. Webb
Keyword(s):  
Reynolds Number ◽  
Water Depth ◽  
Hydraulic Jump ◽  
Smooth Surface ◽  
Frictional Resistance ◽  
Jet Impingement ◽  
Liquid Jet ◽  
Patterned Surfaces ◽  
Number Range ◽  
Patterned Surface

This paper reports experimental results characterizing the hydraulic jumps that form due to liquid jet impingement on micro-patterned surfaces with alternating micro-ribs and cavities. The surfaces are characterized by the cavity fraction, which is defined as the width of a cavity divided by the combined width of a cavity and an adjoining rib. The surfaces are all hydrophilic and thus the cavity regions are wetted during the impingement process. Four different surface designs were studied, with respective cavity fractions of 0 (smooth surface), 0.5, 0.8, and 0.93. The experimental data spans a Weber number range (based on the jet velocity and diameter) of 600 to 2100 and a corresponding Reynolds number range of 11500 to 21400. As with jet impingement on a smooth surface, when a liquid jet strikes a ribbed surface it then moves radially outward in a thin film and eventually experiences a hydraulic jump, where the thickness of the film increases by an order of magnitude, and the velocity decreases accordingly. However, the anisotropy of the patterned surface causes a disparity in frictional resistance dependent upon the direction of the flow relative to the orientation of the ribs. This results in a hydraulic jump which is elliptical rather than circular in shape, where the major axis of the ellipse is aligned parallel to the ribs, concomitant with the frictional resistance being smallest parallel to the ribs and greatest perpendicular to the ribs. When the water depth downstream of the jump was imposed at a predetermined value, the major and minor axis of the jump decreased with increasing water depth, following classical hydraulic jump behavior. The experimental results indicate that for a given cavity fraction and downstream depth, the radius of the jump increases with increasing Reynolds number. At a specified Reynolds number and downstream depth, the hydraulic jump radius in the direction parallel to the ribs of a patterned surface is nominally equal to the jump radius for a smooth surface, regardless of cavity fraction. The jump radius perpendicular to the ribs is notably less than that for a smooth surface, and this radius decreases with increasing cavity fraction.

Liquid Jet Impingement Cooling of a Rotating Disk

1986 ◽  
Vol 108 (3) ◽  
pp. 540-546 ◽  
Author(s):  
H. J. Carper ◽  
J. J. Saavedra ◽  
T. Suwanprateep
Keyword(s):  
Reynolds Number ◽  
Average Nusselt Number ◽  
Convective Heat Transfer Coefficient ◽  
Jet Impingement ◽  
Rotating Disk ◽  
Liquid Jet ◽  
Flow Rates ◽  
Impingement Cooling ◽  
Angular Velocities ◽  
Jet Nozzle

Results are presented from an experimental study conducted to determine the average convective heat transfer coefficient for the side of a rotating disk, with an approximately uniform surface temperature, cooled by a single liquid jet of oil impinging normal to the surface. Tests were conducted over a range of jet flow rates, jet temperatures, jet radial positions, and disk angular velocities with various combinations of three jet nozzle and disk diameters. Correlations are presented that relate the average Nusselt number to rotational Reynolds number, jet Reynolds number, jet Prandtl number, and dimensionless jet radial position.

Splattering During Turbulent Liquid Jet Impingement on Solid Targets

1994 ◽  
Vol 116 (2) ◽  
pp. 338-344 ◽  
Author(s):  
Sourav K. Bhunia ◽  
John H. Lienhard
Keyword(s):  
Jet Impingement ◽  
Reynolds Numbers ◽  
Turbulent Pipe Flow ◽  
Liquid Jet ◽  
Straight Tube ◽  
Aerosol Formation ◽  
Transfer Processes ◽  
Onset Condition ◽  
Impingement Heat Transfer ◽  
Complete Study

In turbulent liquid jet impingement, a spray of droplets often breaks off of the liquid layer formed on the target. This splattering of liquid alters the efficiencies of jet impingement heat transfer processes and chemical containment safety devices, and leads to problems of aerosol formation in jet impingement cleaning processes. In this paper, we present a more complete study of splattering and improved correlations that extend and supersede our previous reports on this topic. We report experimental results on the amount of splattering for jets of water, isopropanol-water solutions, and soap-water mixtures. Jets were produced by straight tube nozzles of diameter 0.8–5.8 mm, with fully developed turbulent pipe-flow upstream of the nozzle exit. These experiments cover Weber numbers between 130-31,000, Reynolds numbers between 2700-98,000, and nozzle-to-target separations of 0.2 ≤ l/d ≤ 125. Splattering of up to 75 percent of the incoming jet liquid is observed. The results show that only the Weber number and l/d affect the fraction of jet liquid splattered. The presence of surfactants does not alter the splattering. A new correlation for the onset condition for splattering is given. In addition, we establish the range of applicability of the model of Lienhard et al. (1992) and we provide a more accurate set of coefficients for their correlation.

The Spread Of Transient Circular Liquid Jet And Hydraulic Jump Formation

2021 ◽  
Author(s):  
Abdelkader Baayoun ◽  
Yunpeng Wang ◽  
Roger Khayat
Keyword(s):  
Hydraulic Jump ◽  
Liquid Jet

Ablation of a Solid Material by High Temperature Liquid Jet Impingement: An Application to Corium Jet Impingement on a Sfr Core-Catcher

2021 ◽  
Author(s):  
Alexandre Lecoanet ◽  
Michel Gradeck ◽  
Xiaoyang Gaus-Liu ◽  
Thomas Cron ◽  
Beatrix Fluhrer ◽  
...  
Keyword(s):  
High Temperature ◽  
Deep Understanding ◽  
Jet Impingement ◽  
Severe Accident ◽  
Mitigation Measures ◽  
Liquid Jet ◽  
Cavity Formation ◽  
The Core ◽  
Core Catcher ◽  
Temperature Liquid

Abstract This paper deals with ablation of a solid by a high temperature liquid jet. This phenomenon is a key issue to maintain the vessel integrity during the course of a nuclear reactor severe accident with melting of the core. Depending on the course of such an accident, high temperature corium jets might impinge and ablate the vessel material leading to its potential failure. Since Fukushima Daiichi accident, new mitigation measures are under study. As a designed safety feature of a future European SFR, bearing the purpose of quickly draining of the corium out of the core and protecting the reactor vessel against the attack of molten melt, the in-core corium is relocated via discharge tubes to an in-vessel core-catcher has been planned. The core-catcher design to withstand corium jet impingement demands the knowledge of very complex phenomena such as the dynamics of cavity formation and associated heat transfers. Even studied in the past, no complete data are available concerning the variation of jet parameters and solid structure materials. For a deep understanding of this phenomenon, new tests have been performed using both simulant and prototypical jet and core catcher materials. Part of these tests have been done at University of Lorraine using hot liquid water impinging on transparent ice block allowing for the visualizations of the cavity formation. Other tests have been performed in Karlsruhe Institute of Technology using liquid steel impinging on steel block.

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