scholarly journals Effects of a water hammer and cavitation on jet formation in a test tube

2015 ◽  
Vol 787 ◽  
pp. 224-236 ◽  
Author(s):  
Akihito Kiyama ◽  
Yoshiyuki Tagawa ◽  
Keita Ando ◽  
Masaharu Kameda
Keyword(s):  
Pressure Wave ◽  
Flow Analysis ◽  
Water Hammer ◽  
Test Tube ◽  
Liquid Interface ◽  
Phase Changes ◽  
Liquid Jet ◽  
Jet Formation ◽  
Wave Interactions ◽  
The One

We investigate the motion of a gas–liquid interface in a test tube induced by a large acceleration via impulsive force. We conduct simple experiments in which the tube partially filled with a liquid falls under gravity and hits a rigid floor. A curved gas–liquid interface inside the tube reverses and eventually forms a so-called focused jet. In our experiments, there arises either vibration of the interface or an increment in the velocity of the liquid jet, accompanied by the onset of cavitation in the liquid column. These phenomena cannot be explained by a considering pressure impulse in a classical potential flow analysis, which does not account for finite speeds of sound or phase changes. Here we model such water-hammer events as a result of the one-dimensional propagation of a pressure wave and its interaction with boundaries through acoustic impedance mismatching. The method of characteristics is applied to describe pressure-wave interactions and the subsequent cavitation. The model proposed is found to be able to capture the time-dependent characteristics of the liquid jet.

Dynamics of a bump of the gas-liquid interface on which a submerged liquid jet impinges

2002 ◽  
Author(s):  
Kunio Kataoka ◽  
Jianxing Zheng ◽  
Tokuo Yoshimura ◽  
Naoto Ohmura
Keyword(s):  
Liquid Interface ◽  
Liquid Jet

scholarly journals A Story on the Wave Spectral Properties of Water Hammer

2021 ◽  
Author(s):  
Shiblu Sarker
Keyword(s):  
Spectral Density ◽  
Pressure Wave ◽  
Spectral Properties ◽  
Unsteady Flows ◽  
Water Hammer ◽  
Excessive Pressure ◽  
Pipe System ◽  
Power Spectral ◽  
Physical Information ◽  
Frequency Domain Approach

The prevention of excessive pressure build-up in pipelines requires a thorough understanding of water hammer. Seminal scholars have looked into this phenomena and come up with useful solutions using theoretical techniques. In this study, We propose a power spectral density approach on the pressure wave generated by water hammer in order to improve our understanding of the frequency-domain approach. This approach has the potential to explain some useful properties of the unsteady flow at a given section, attempting to make investigations of the dynamic characteristics of pipelines more effectively. We employ a basic pipe system to mimic the proposed approach based on the data acquired, which yields a lot of relevant physical information for pipeline construction. The proposed method is expected to be useful and efficient in gaining a better understanding of the intricate properties of unsteady flows as well as sound acoustics in a pipe system and their design.

scholarly journals Assessment of water hammer effects on boiling water nuclear reactor core dynamics

2007 ◽  
Vol 22 (1) ◽  
pp. 18-33 ◽  
Author(s):  
Anis Bousbia-Salah
Keyword(s):  
Pressure Wave ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Reactor ◽  
Reactor Core ◽  
Water Hammer ◽  
Pressure Wave Amplitude ◽  
Sensitivity Studies ◽  
Rapid Transients ◽  
Complex Phenomena

Complex phenomena, as water hammer transients, occurring in nuclear power plants are still not very well investigated by the current best estimate computational tools. Within this frame work, a rapid positive reactivity addition into the core generated by a water hammer transient is considered. The numerical simulation of such phenomena was carried out using the coupled RELAP5/PARCS code. An over all data comparison shows good agreement between the calculated and measured core pressure wave trends. However, the predicted power response during the excursion phase did not correctly match the experimental tendency. Because of this, sensitivity studies have been carried out in order to identify the most influential parameters that govern the dynamics of the power excursion. After investigating the pressure wave amplitude and the void feed back responses, it was found that the disagreement between the calculated and measured data occurs mainly due to the RELAP5 low void condensation rate which seems to be questionable during rapid transients. .

ADVICE FROM AN OLD DOCTOR TO A YOUNG DOCTOR ON "KEEPING UP"

PEDIATRICS ◽  
1974 ◽  
Vol 54 (3) ◽  
pp. 357-357
Author(s):  
A. Hailey
Keyword(s):  
Test Tube ◽  
Young Doctor ◽  
Time Out ◽  
The One ◽  
Reading Textbooks ◽  
The Way

"You're young, you're full of spice and vinegar—that's good. You know your stuff too. You're up-todate—you know things that I never did and never will now. Take my advice and try to keep it that way. It'll be tough to do; make no mistake about it." He waved toward the desk he had just vacated. "You'll sit in that chair and the phone will ring, and it'll be the administrator—talking about budgets. Next mmute one of the lab staff will want to quit; and you'll have to smooth that out. And the doctors will come in, and they'll want this bit of information and that." The old man smiled thinly. "Then you'll get the salesman—the man with the unbreakable test tube and the burner that never goes out. And when you're through seeing him there'll be another and another and another. Until at the end of a day you'll wonder what happened to it and what you've accomplished, what you've achieved." "That's the way the next day can go, and the next, and the one after that. Until you find a year has slipped by, and another, and another. And while you're doing all this you'll send other people on courses to hear about the new things in medicine—because you can't take time out to go yourself. And you'll quit investigation and research; and because you work so hard, you'll be tired at night, and you won't feel like reading textbooks. And then suddenly, one day, you'll find everything you knew is out of date.

Liquid jet formation during a suspended liquid suction process

2020 ◽  
Vol 114 ◽  
pp. 109952
Author(s):  
Liang Hu ◽  
Hanghang Xu ◽  
Mingbo Li ◽  
Weiting Liu ◽  
Wenyu Chen ◽  
...  
Keyword(s):  
Liquid Jet ◽  
Jet Formation

Cinematographic Analysis of Counter Jet Formation in a Single Cavitation Bubble Collapse Flow

2011 ◽  
Vol 27 (2) ◽  
pp. 253-266 ◽  
Author(s):  
S.-H. Yang ◽  
S.-Y. Jaw ◽  
K.-C. Yeh
Keyword(s):  
Flow Field ◽  
Cavitation Bubble ◽  
Pressure Wave ◽  
Bubble Surface ◽  
Bubble Collapse ◽  
Solid Boundary ◽  
Liquid Jet ◽  
Pressure Waves ◽  
Field Variation ◽  
Critical Position

ABSTRACTThis study utilized a U-shape platform device to generate a single cavitation bubble for the detail analysis of the flow field characteristics and the cause of the counter jet during the process of bubble collapse induced by pressure wave. A series of bubble collapse flows induced by pressure waves of different strengths are investigated by positioning the cavitation bubble at different stand-off distances to the solid boundary. It is found that the Kelvin-Helmholtz vortices are formed when the liquid jet induced by the pressure wave penetrates the bubble surface. If the bubble center to the solid boundary is within one to three times the bubble's radius, a stagnation ring will form on the boundary when impacted by the penetrated jet. The liquid inside the stagnation ring is squeezed toward the center of the ring to form a counter jet after the bubble collapses. At the critical position, where the bubble center from the solid boundary is about three times the bubble's radius, the bubble collapse flows will vary. Depending on the strengths of the pressure waves applied, either just the Kelvin-Helmholtz vortices form around the penetrated jet or the penetrated jet impacts the boundary directly to generate the stagnation ring and the counter jet flow. This phenomenon used the particle image velocimetry method can be clearly revealed the flow field variation of the counter jet. If the bubble surface is in contact with the solid boundary, the liquid jet can only splash radially without producing the stagnation ring and the counter jet. The complex phenomenon of cavitation bubble collapse flows are clearly manifested in this study.

Efficient Iron Removal to Produce High Purity Quartz Sand by Micro-Inclusion Bursting Using Microwave Pretreatment Combined with Different Acid

2020 ◽  
Vol 1001 ◽  
pp. 28-34
Author(s):  
Fei Fei Li ◽  
Xue Song Jiang ◽  
Jing Wei Li ◽  
Bo Yuan Ban ◽  
Jian Chen
Keyword(s):  
Acid Leaching ◽  
Microwave Treatment ◽  
Phase Changes ◽  
Low Energy ◽  
Local Phase ◽  
Selective Heating ◽  
Low Energy Consumption ◽  
Fast Processing ◽  
The One ◽  
Optimized Conditions

The one of major impurities in quartz is iron, which has a great impact on the properties of the material and should be be strictly removed in many applications. In this study, a low-energy consumption, simple, fast processing is introduced by combination microwave treatment with different acid leaching. Selective heating of microwaves is used to process quartz, causing local phase changes to improve the purification effect. Acid leaching was used to remove the iron in the quartz matrix. Under optimized conditions, the iron content can be reduced to below 0.167 ppmw with one single purification pass.

scholarly journals Investigation of Zero Moment Point in a Partially Filled Liquid Vessel Subjected to Roll Motion

2020 ◽  
Vol 10 (11) ◽  
pp. 3992
Author(s):  
Muhammad Usman ◽  
Muhammad Sajid ◽  
Emad Uddin ◽  
Yasar Ayaz
Keyword(s):  
Autonomous Vehicles ◽  
Center Of Mass ◽  
Flow Analysis ◽  
Liquid Interface ◽  
Liquid Region ◽  
Time Step ◽  
Two Phase ◽  
Zero Moment Point ◽  
Zero Moment ◽  
Air Liquid Interface

Liquid-handling robots are designed to dispense sub-microliter quantities of fluids for applications including laboratory tests. When larger amounts of liquids are involved, sloshing must be considered as a parameter affecting stability, which is of significance for autonomous vehicles. The measurement and quantification of slosh in enclosed volumes poses a challenge to researchers who have traditionally resorted to tracking the air–liquid interface for two-phase flow analysis. There is a need for a simpler method to predict rollover in these applications. In this work, a novel solution to address this problem is proposed in the form of the Zero Moment Point (ZMP) of a dynamic liquid region. Computational experiments of a partially filled, two-dimensional liquid vessel were carried out using the Volume of Fluid (VOF) method in a finite volume based open-source computational fluid dynamics solver. The movement of the air–liquid interface was tracked, while the Center of Mass and the resulting Zero Moment Point were determined from the numerical simulations at each time step. The computational model was validated by comparing the wall pressure and movement of the liquid-free surface to experimentally obtained values. It was concluded that for a dynamic liquid domain, the Zero Moment Point can be instrumental in determining the stability of partially filled containers subjected to sloshing.

Bubble collapse and liquid jet formation in non-newtonian liquids

AIChE Journal ◽  
1999 ◽  
Vol 45 (12) ◽  
pp. 2653-2656 ◽  
Author(s):  
S. W. J. Brown ◽  
P. R. Williams
Keyword(s):  
Bubble Collapse ◽  
Liquid Jet ◽  
Jet Formation ◽  
Newtonian Liquids
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