scholarly journals The Rate of Growth of Vapor Bubbles in Superheated Water

1953 ◽  
Vol 20 (4) ◽  
pp. 537-545
Author(s):  
Paul Dergarabedian
Keyword(s):  
Bubble Radius ◽  
Equation Of Motion ◽  
Heat Diffusion ◽  
Air Bubbles ◽  
Finite Range ◽  
Superheated Water ◽  
Vapor Bubbles ◽  
Bubble Wall ◽  
Air Content ◽  
Rate Of Growth

Abstract Calculations are presented for the dynamic stability of vapor and air bubbles in superheated water. These calculations indicate that the values of the bubble radii for which the equilibrium is unstable are restricted to a finite range of radii whose values are governed by the temperature of the water and the initial air content in the bubble. Two theoretical solutions for the rate of growth of these unstable bubbles are considered: (a) Solution of the equation of motion of the bubble radius with the assumption that there is no heat diffusion across the bubble wall; (b) solution which includes the effect of heat diffusion. The two solutions differ appreciably. These two solutions are then compared with the experimental data on the growth of the vapor bubbles in superheated water. This comparison shows agreement with the solution with the effect of heat diffusion included.

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.

Measurement of air‐gun bubble oscillations

Geophysics ◽  
1998 ◽  
Vol 63 (6) ◽  
pp. 2009-2024 ◽  
Author(s):  
Anton Ziolkowski
Keyword(s):  
Acoustic Radiation ◽  
Bubble Radius ◽  
Real Data ◽  
Equation Of Motion ◽  
Smooth Transition ◽  
Bubble Wall ◽  
Wall Velocity ◽  
Pressure Transducers ◽  
Air Gun ◽  
Bubble Oscillations

In this paper, I provide a theoretical basis for a practical approach to measuring the pressure field of an air gun array and present an algorithm for computing its wavefield from pressure measurements made at known positions in the vicinity of the gun ports. The theory for the oscillations of a single bubble is essentially a straight‐forward extension of Lamb’s original paper and provides a continuous, smooth transition from the oscillating wall of the bubble to the far‐field, preserving both the fluid flow and the acoustic radiation, all to the same accuracy and valid for bubbles with initial pressures up to about 200 atm (3000 psi or 20 MPa). The simplifying assumption, based on an argument of Lamb, is that the particle velocity potential obeys the linear acoustic wave equation. This is used then in the basic dynamic and kinematic equations to lead, without further approximations, to the nonlinear equation of motion of the bubble wall and the wavefield in the water. Given the initial bubble radius, the initial bubble wall velocity, and the pressure variation at any point inside or outside the bubble, the algorithm can be used to calculate the bubble motion and the acoustic wavefield. The interaction among air‐gun bubbles and the resultant total wavefield is formulated using the notional source concept, in which each bubble is replaced by an equivalent notional bubble obeying the same equation of motion but oscillating in water of hydrostatic pressure, thus allowing the wavefields of the notional bubbles to be superposed. A separate calibration experiment using the same pressure transducers and firing the guns individually allows the initial values of the bubble radius and bubble wall velocity to be determined for each gun. An appendix to the paper provides a test of the algorithm on real data from a single gun.

The Behavior of Bubbles in Non-Newtonian Lubricants

1977 ◽  
Vol 99 (4) ◽  
pp. 455-461 ◽  
Author(s):  
A. Shima ◽  
T. Tsujino
Keyword(s):  
Rheological Properties ◽  
Bubble Radius ◽  
Equation Of Motion ◽  
Crude Oils ◽  
Bubble Wall ◽  
Pressure Equation ◽  
Cavitation Damage ◽  
Lubricating Oils ◽  
Cavitation Bubbles ◽  
Impulse Pressure

The behavior of cavitation bubbles and the impulse pressure occurring from the bubble in non-Newtonian lubricants are analyzed as one of the studies on cavitation which is caused on the bearing metals and oil pressure valves. That is, the equation of motion for a bubble and the pressure equation can be derived by using the Sisko model which well represents the rheological properties of lubricants (lubricating greases, and crude oils in place of lubricating oils), and the variation with time of the bubble radius and the pressure and velocity at the bubble wall in greases and crude oils are numerically obtained. In consequence, it was found that the impulse pressure occurring from the collapse of comparatively large bubbles can be a cause for the cavitation damage.

Explanation of the Influence of Inflow Air Content on the Lift of Cavitating Hydrofoils

2018 ◽  
Vol 140 (8) ◽  
Author(s):  
Eduard Amromin
Keyword(s):  
Experimental Data ◽  
Theoretical Study ◽  
Lift Coefficient ◽  
Cavity Surface ◽  
Air Bubbles ◽  
Incoming Flow ◽  
Fluid Density ◽  
Air Content ◽  
Theoretical Results ◽  
Good Agreement

According to several known experiments, an increase of the incoming flow air content can increase the hydrofoil lift coefficient. The presented theoretical study shows that such increase is associated with the decrease of the fluid density at the cavity surface. This decrease is caused by entrainment of air bubbles to the cavity from the surrounding flow. The theoretical results based on such explanation are in a good agreement with the earlier published experimental data for NACA0015.

Collective Effects on the Growth of Vapor Bubbles in a Superheated Liquid

1984 ◽  
Vol 106 (4) ◽  
pp. 486-490 ◽  
Author(s):  
G. L. Chahine ◽  
H. L. Liu
Keyword(s):  
Collective Behavior ◽  
Bubble Growth ◽  
Theoretical Study ◽  
Pressure Field ◽  
Bubble Radius ◽  
Significant Inhibition ◽  
Collective Effects ◽  
Superheated Liquid ◽  
Vapor Bubbles ◽  
Bubble Interaction

The problem of the growth of a spherical isolated bubble in a superheated liquid has been extensively studied. However, very little work has been done for the case of a cloud of bubbles. The collective behavior of the bubbles departs considerably from that of a single isolated bubble, due to the cumulative modification of the pressure field from all other bubbles. This paper presents a theoretical study on bubble interaction in a superheated liquid during the growth stage. The solution is sought in terms of matched asymptotic expansions in powers of ε, the ratio between rb0, a characteristic bubble radius and l0, the interbubble distance. Numerical results show a significant inhibition of the bubble growth rate due to the presence of interacting bubbles. In addition, the temperature at the bubble wall decreases at a slower rate. Consequently, the overall heat exchange during the bubble growth is reduced.

The Pore-network Modelling of the Infiltration Experiments Performed on Unsaturated Coarse Sands

2021 ◽  
Author(s):  
Tomáš Princ ◽  
Michal Snehota
Keyword(s):  
Hydraulic Conductivity ◽  
Network Model ◽  
Pore Network ◽  
Pore Network Model ◽  
Air Bubbles ◽  
Network Modelling ◽  
Air Content ◽  
Pore Network Modelling ◽  
X Ray Computed ◽  
Entrapped Air

<p>The research focused on the simulation of the previous experiment described by Princ et al. (2020). The relationship between entrapped air content (<em>ω</em>) and the corresponding satiated hydraulic conductivity (<em>K</em>) was investigated for two coarse sands, in the experiment. Additionally the amount and distribution of air bubbles were quantified by X-ray computed tomography.</p><p>The pore-network model based on OpenPNM platform (Gostick et al. 2016) was used to attempt simulation of a redistribution of the air bubbles after infiltration. Satiated hydraulic conductivity was determined to obtain the <em>K</em>(<em>ω</em>) relationship. The results from pore-network model were compared with the results from experiments.</p><p>Gostick et al. (2016). Computing in Science & Engineering. 18(4), p60-74.</p><p>Princ et al. (2020). Water. 12(2), p1-19.</p>

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