Bubble Formation Due to a Submerged Capillary Tube in Quiescent and Coflowing Streams

1970 ◽  
Vol 92 (4) ◽  
pp. 705-711 ◽  
Author(s):  
S. C. Chuang ◽  
V. W. Goldschmidt
Keyword(s):  
Gas Flow ◽  
Capillary Tube ◽  
Bubble Formation ◽  
Viscous Drag ◽  
Proposed Model ◽  
Mass Coefficient ◽  
Small Tube ◽  
Flow Through ◽  
Added Mass Coefficient ◽  
Good Agreement

The case of bubble formation in both quiescent and moving streams due to the injection of a constant gas flow through a small tube is considered. Relationships predicting the expected size and quantity of bubbles generated are proposed. These are compared with measurements taken with stream velocities up to 9 ft/sec, while generating gas bubbles from 40 to 700 microns in diameter. For the case of generation in a quiescent stream the forces due to the virtual mass, surface tension, viscous drag, buoyancy, and the wake formed by the preceding bubble are accounted for. There still remains some question (only partly answered by a comparison with measurements) as to the proper added mass coefficient and the geometry of the bubble previous to detachment, as well as an adequate estimate of the interaction with a preceding bubble’s wake. The proposed model for generation in a moving stream is in good agreement with actual measurements for co-flowing velocities between 1 and 9 fps and capillary tubes in the order of 10−3 cm in dia.

The dispersion of matter in turbulent flow through a pipe

1954 ◽  
Vol 223 (1155) ◽  
pp. 446-468 ◽  
Keyword(s):  
Turbulent Flow ◽  
Capillary Tube ◽  
Resistance Coefficient ◽  
Mean Flow ◽  
Combined Action ◽  
Flow Through ◽  
The Mean ◽  
Coefficient Of Diffusion ◽  
Good Agreement ◽  
Made In

The dispersion of soluble matter introduced into a slow stream of solvent in a capillary tube can be described by means of a virtual coefficient of diffusion (Taylor 1953 a ) which represents the combined action of variation of velocity over the cross-section of the tube and molecluar diffusion in a radial direction. The analogous problem of dispersion in turbulent flow can be solved in the same way. In that case the virtual coefficient of diffusion K is found to be 10∙1 av * or K = 7∙14 aU √ γ . Here a is the radius of the pipe, U is the mean flow velocity, γ is the resistance coefficient and v * ‘friction velocity’. Experiments are described in which brine was injected into a straight 3/8 in. pipe and the conductivity recorded at a point downstream. The theoretical prediction was verified with both smooth and very rough pipes. A small amount of curvature was found to increase the dispersion greatly. When a fluid is forced into a pipe already full of another fluid with which it can mix, the interface spreads through a length S as it passes down the pipe. When the interface has moved through a distance X , theory leads to the formula S 2 = 437 aX ( v * / U ). Good agreement is found when this prediction is compared with experiments made in long pipe lines in America.

The Relationship Between Breach Development and the Depressurization Transient During Axial Rupture of a Gas-Pressurized Steel Pipe

1982 ◽  
Vol 104 (1) ◽  
pp. 20-24 ◽  
Author(s):  
M. R. Baum
Keyword(s):  
Rarefaction Wave ◽  
Gas Flow ◽  
Theoretical Models ◽  
Observation Point ◽  
Steel Pipe ◽  
Growth Data ◽  
Flow Through ◽  
The Relationship ◽  
Experimental Pressure ◽  
Good Agreement

Theoretical models are developed to predict the depressurization generated by a propagating axial rupture in a gas-pressurized steel pipe. The pressure transient is composed of a relatively slow depressurization within the rarefaction wave which propagates through the undisturbed gas ahead of the developing breach and a rapid depressurization within the breach zone. The models combine a simplified one-dimensional treatment of the gas flow local to the breach with experimental breach area growth data. An instantaneous steady flow through the developing breach is assumed to determine the boundary condition for the rarefaction wave. The breach zone depressurization is assumed to be dominated by the transverse wave action initiated by the arrival of the breach at the observation point. In both cases the predicted transients are in good agreement with experimental pressure histories.

Effect of Nanoparticles on the Spreading of Bubble Triple Line on Top of a Stainless Steel Substrate Nozzle

2010 ◽  
Author(s):  
Saeid Vafaei ◽  
Dongsheng Wen
Keyword(s):  
Stainless Steel ◽  
Gas Flow ◽  
Stainless Steel Substrate ◽  
Liquid Droplet ◽  
Steel Substrate ◽  
Bubble Formation ◽  
Triple Line ◽  
Characteristic Points ◽  
Substrate Plate ◽  
Good Agreement

The purpose of this study is to investigate the effect of gold nanofluid on the formation of gas bubbles on top of a stainless steel substrate plate nozzle. The experiment reveals a unique phenomenon of enhanced pinning of the triple line of gold nanofluids for bubbles forming on the substrate plate, i.e the gold nanoparticles are found to prevent the spreading of the triple line during the bubble formation. Different to the liquid droplet measurement, the bubble contact angle is found to be slightly larger for formation of bubbles inside gold nanofluids. It is also observed that bubbles develop earlier inside the nanofluids with reduced bubble departure volume and increased bubble formation frequency. The shape of the bubble is found to be in good agreement with predictions of the Laplace-Young equation under the low gas flow rates inside water. Such a good agreement is also observed for bubbles forming inside nanofluids except a few characteristic points. The variation of solid surface tensions and the resultant force balances at the triple line are believed to be responsible for the modified dynamics of the triple line inside gold nanofluids and subsequent bubble formation.

Poiseuille gas flow in the transition regime II. Application of the general theory

1967 ◽  
Vol 301 (1467) ◽  
pp. 401-409 ◽  
Keyword(s):  
Relaxation Time ◽  
Gas Flow ◽  
Capillary Tube ◽  
Collision Operator ◽  
Mean Free Path ◽  
Transition Regime ◽  
Tube Radius ◽  
Time Approximation ◽  
Relaxation Time Approximation ◽  
Flow Through

The general formulae given in the previous paper are investigated in detail using a simple relaxation-time approximation for the collision operator, and numerical results are obtained for the total gas flow through a capillary tube at various values of the ratio of tube radius to collision mean free path. For all values of this ratio, the results obtained agree with experiment to within about 2%.

Simple Model for Bubble-Wall Interaction

2014 ◽  
Author(s):  
Etienne Pelletier ◽  
C. Beguin ◽  
S. Etienne
Keyword(s):  
Bubble Radius ◽  
Viscous Drag ◽  
Air Bubbles ◽  
Bubble Wall ◽  
Proposed Model ◽  
Horizontal Wall ◽  
Wall Interaction ◽  
Definition Of ◽  
Potential Pressure ◽  
Good Agreement

We have developed a model for an ellipsoidal bubble colliding with a rigid horizontal wall based on potential flow theory. The model is then compared with experiments of air bubbles surrounded by water impacting a wall. 70 impacts were observed with bubble radius between 0.3 and 2 mm and different trajectory types (helicoidal, zig-zag). Deformation and height of the first impact are the main comparison points. The proposed model is in good agreement with the height of the rebound but tends to overestimate the maximal compression for both types of trajectories. We also propose a new relation for the viscous drag coefficient correction induced by the wall confinement as well as the definition of potential pressure forces acting on bubbles close to a wall.

The Drag and Added-Mass Coefficients of Various Buffers Vibrating Axially in Water

1991 ◽  
Vol 113 (2) ◽  
pp. 80-86 ◽  
Author(s):  
K. Aso ◽  
K. Kan ◽  
H. Doki ◽  
M. Mori
Keyword(s):  
Drag Coefficient ◽  
Deep Sea ◽  
Longitudinal Vibration ◽  
Mineral Resources ◽  
Added Mass ◽  
New Method ◽  
Fluid Forces ◽  
Mass Coefficient ◽  
Added Mass Coefficient ◽  
Good Agreement

In order to analyze the longitudinal vibration of a pipe-string for mining mineral resources at deep-sea bottoms, the fluid forces acting on the buffer and pump-module attached to the pipe-string must be evaluated in advance. In this study, first, a new method was developed for determining the drag and added-mass coefficients of a buffer vibrating axially, and then both coefficients for various shapes of buffers were determined. The results obtained on the spherical buffer-models proved to be in fairly good agreement with those by Sarpkaya and showed the validity of the new method. Furthermore, the results of other buffer-models indicated that there was a good correlation between those coefficients and Keulegan-Carpenter number, KC, and that as KC increases, the drag coefficient decreases exponentially and the added-mass coefficient increases or decreases linearly according to the shapes of the buffer models.

Submerged Gas Injection in Microgravity

2002 ◽  
Author(s):  
J. Carrera ◽  
R. N. Parthasarathy ◽  
S. R. Gollahalli
Keyword(s):  
Surface Tension ◽  
Weber Number ◽  
Gas Flow ◽  
Capillary Tube ◽  
Bubble Formation ◽  
Gas Injection ◽  
Flow Regimes ◽  
Flowing Liquid ◽  
Flow Rates ◽  
Reduced Surface

The effects of buoyancy on the flow regimes of submerged gas injection were studied in this investigation. A capillary tube submerged in water was used for gas injection in microgravity and terrestrial conditions, and the resulting flow regimes and bubble sizes were documented. The effects of liquid co-flow and reduced surface tension were also analyzed. Under reduced gravity, three flow regimes were observed over the range of conditions tested. At low gas flow rates, the bubbles did not detach from the injector, forming an interconnected bubble cluster that adhered to the injector. Single bubbles started detaching and moving away from the injector when the Weber number reached a value around 3. At gas flow rates corresponding to a Weber number value of 10, the bubble coalescence regime was observed near the injector. It was found that the absence of buoyancy prevented the formation of the jetting regime. For all gas throughputs, the co-flowing liquid aided the detachment of the bubbles, resulting in the generation of more uniform bubbles than in quiescent liquids. The presence of co-flow resulted in a smaller bubble size accompanied by an increased frequency of bubble formation. Reduced surface tension produced a similar effect, resulting in smaller bubbles.

A COMPREHENSIVE MODEL FOR CAPILLARY PRESSURE DIFFERENCE ACROSS A DROP/BUBBLE FLOWING THROUGH A CONSTRICTED CAPILLARY

2015 ◽  
Vol 22 (06) ◽  
pp. 1550077 ◽  
Author(s):  
MINGCHAO LIANG ◽  
JUNHONG WEI ◽  
HONGMEI HAN ◽  
CHENGGUO FU ◽  
JIANJUN LIU
Keyword(s):  
Capillary Pressure ◽  
Pressure Difference ◽  
Chemical Engineering ◽  
Bubble Formation ◽  
Comprehensive Model ◽  
Science And Engineering ◽  
Proposed Model ◽  
Model Predictions ◽  
Interface Science ◽  
Good Agreement

The capillary pressure is one of the crucial parameters in many science and engineering applications such as composite materials, interface science, chemical engineering, oil exploration, etc. The drop/bubble formation and its mechanisms that affect the permeability of porous media have steadily attracted much attention in the past. When a drop/bubble moves from a larger capillary to a smaller one, it is often obstructed by an additional pressure difference caused by the capillary force. In this paper, a comprehensive model is derived for the capillary pressure difference when a drop/bubble flows through a constricted capillary, i.e. a geometrically constricted passage with an abrupt change in radius. The proposed model is expressed as a function of the smaller capillary radius, pore-throat ratio, contact angle, surface tension and length of the drop/bubble in the smaller capillary. The model predictions are compared with the available experimental data, and good agreement is found between them.

Wall Pressure Profile Around Cylindrical Rods in Yawed Gas Flow

2011 ◽  
Vol 133 (7) ◽  
Author(s):  
R. G. Marino ◽  
A. Clausse ◽  
V. A. Herrero ◽  
N. Silin ◽  
G. Saravia
Keyword(s):  
Flow Rate ◽  
Inclination Angle ◽  
Atmospheric Pressure ◽  
Gas Flow ◽  
Pressure Coefficient ◽  
Pressure Profile ◽  
Inviscid Flow ◽  
Cylindrical Tubes ◽  
Flow Through ◽  
Good Agreement

The distribution of wall pressures in yawed flow through an array of cylindrical tubes inclined at different angles between 30° and 90° was experimentally studied using air at atmospheric pressure for 2290 ≤ Re ≤ 6100. The experiments show that the pressure coefficient is strongly influenced by the inclination angle, and only marginally affected by the flow rate within the tested range. The pressure behavior at the gap was calculated by assuming curved streamlines and inviscid flow, showing good agreement with measurements performed at the rod wall in the gap position.

The Influence of Exhaust Poppet Valve Gas Flow on Reciprocating Engine Noise

1975 ◽  
Vol 189 (1) ◽  
pp. 461-469 ◽  
Author(s):  
T. J. Williams ◽  
J. B. Cox
Keyword(s):  
Gas Flow ◽  
Combustion Engine ◽  
Flow Characteristics ◽  
Exhaust System ◽  
Gas Flows ◽  
Frequency Spectra ◽  
Reciprocating Engine ◽  
Flow Through ◽  
Field Noise ◽  
Good Agreement

The far field noise generated by cold air flowing through stationary and reciprocating exhaust poppet valves into a cylindrical duct or pipe has been investigated. A method of predicting the intensity and frequency spectrum of the noise generated in such circumstances in terms of the known or assumed geometry and flow characteristics of the valves is presented. Comparisons of the predicted frequency spectra with measured values show good agreement for steady gas flows through stationary valves and for unsteady flow through a simplified exhaust system of a motored single cylinder internal combustion engine.

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