Unsteady propagation of a liquid plug in a liquid-lined straight tube

An experimental study is performed to extract minute gas bubbles from liquids flowing in a simulated cardiopulmonary bypass system using a Venturi-aspirator unit. In other words, oxygen bubbles in oxygenated blood are simulated by air bubbles in water with AP30 (about same viscosity as whole blood). This study is intended to determine the feasibility of using a Venturi aspirator unit to extract minute gas bubbles from a simulated cardiopulmonary bypass system. Testing of the Venturi-type bubble extraction is carried out using three different test sections. Two Venturis are used, and a straight tube configuration is used as a control. The two Venturis are similar, with the exception that one has a longer inlet cone which causes the entering liquid to accelerate at a slower rate. Results are obtained for effectiveness of the aspirator unit as functions of total flow rate, extraction suction, suction pressure difference, and hydraulic head. It is concluded from the study that:(i) The effectiveness of the Venturis is typically between 90 and 100 percent. It increases with an increase in suction or suction pressure difference but decreases with an increase in total flow rate.(ii) The Venturi is most suitable for extraction of minute gas bubbles, especially for use with AP30 (whole blood), which yields substantially higher effectiveness than water.(iii) It is anticipated that a Venturi-aspirator unit can be superior to other bubble separation device as the cardiopulmonary bypass system for applications in extra corporeal blood oxygenation.

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Flow and heat transfer of liquid plug and neighboring vapor slugs in a pulsating heat pipe

International Journal of Heat and Mass Transfer ◽

10.1016/j.ijheatmasstransfer.2009.12.042 ◽

2010 ◽

Vol 53 (7-8) ◽

pp. 1260-1268 ◽

Cited By ~ 27

Author(s):

Dazhong Yuan ◽

Wei Qu ◽

Tongze Ma

Keyword(s):

Heat Transfer ◽

Heat Pipe ◽

Pulsating Heat Pipe ◽

Liquid Plug ◽

Flow And Heat Transfer

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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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