Computational Analysis of Liquid Jet Impingement Micro-channel Cooling

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.

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Splattering During Turbulent Liquid Jet Impingement on Solid Targets

Journal of Fluids Engineering ◽

10.1115/1.2910277 ◽

1994 ◽

Vol 116 (2) ◽

pp. 338-344 ◽

Cited By ~ 24

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.

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Effects of varying body forces on isothermal and non isothermal liquid jet impingement

10.33915/etd.2769 ◽

2007 ◽

Cited By ~ 1

Author(s):

Deepak Mehra

Keyword(s):

Jet Impingement ◽

Liquid Jet ◽

Body Forces

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

Journal of Nuclear Engineering and Radiation Science ◽

10.1115/1.4051448 ◽

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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