A model for bubble-bubble and bubble-wall interaction in bubble formation

AIChE Journal ◽  
2005 ◽  
Vol 52 (1) ◽  
pp. 86-98 ◽  
Author(s):  
Zongyuan Xiao ◽  
Reginald B. H. Tan
Keyword(s):  
Bubble Formation ◽  
Bubble Wall ◽  
Wall Interaction

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.

Bubble–wall interaction for asymmetric injection of jets in solid–gas fluidized bed

2013 ◽  
Vol 101 ◽  
pp. 56-68 ◽  
Author(s):  
Apurv Kumar ◽  
Subrat Das ◽  
Daniel Fabijanic ◽  
Weimin Gao ◽  
Peter Hodgson
Keyword(s):  
Fluidized Bed ◽  
Bubble Wall ◽  
Wall Interaction

scholarly journals BUBBLE WALL DYNAMICS, GENERALIZED YUKAWA COUPLINGS AND ADEQUATE ELECTROWEAK BARYOGENESIS IN TWO-HIGGS-DOUBLET MODEL

1996 ◽  
Vol 11 (31) ◽  
pp. 2481-2487 ◽  
Author(s):  
SUSMITA BHOWMIK DUARI ◽  
U.A. YAJNIK
Keyword(s):  
Particle Physics ◽  
Chemical Potential ◽  
Diffusion Processes ◽  
Bubble Formation ◽  
Higgs Doublet ◽  
Bubble Wall ◽  
Electroweak Scale ◽  
Yukawa Couplings ◽  
Doublet Model ◽  
Two Higgs Doublet Model

Baryogenesis at the electroweak scale depends on bubble wall dynamics and particle physics. We trace the dynamics of the relative phase during bubble formation in two-Higgs-doublet model (2HDM) and compute its contribution to the mechanism proposed by McLerran-Shaposhnikov-Turok-Voloshin. This enhances the intrinsic contribution of the diagram and would mean overall enhancement if diffusion processes are taken into account. We also show that in 2HDM with less stringent constraints on Yukawa couplings than those imposed by natural flavor conservation, there are additional diagrams contributing to the effective chemical potential. These two effects can combine with several others to produce adequate asymmetry at the electroweak scale.

Vapor Bubble Interaction With a Superheated Wall

2017 ◽  
Author(s):  
M. Wasy Akhtar
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Vapor Bubble ◽  
Volume Fraction ◽  
Three Dimensional ◽  
Saturation Temperature ◽  
Bubble Wall ◽  
Initial Flow ◽  
Transfer Rates ◽  
Wall Interaction

Sliding bubbles are known to augment heat transfer rates on the surface on which they slide. The pre-cursor problem — the bubble approaching an inclined superheated wall provides the initial flow and thermal field for the sliding bubble problem. An FC-87 vapor bubble rising in a thermally stratified flow field is simulated along with the bubble wall interaction effects. The simulation is conducted on a dynamic octree grid for improved accuracy and efficiency. The evolution of the bubble shape and the wake behind the rising bubble is captured in a three-dimensional model, which takes into account bubble growth due to superheat at the liquid-vapor interface and the effect of interface heat flux on the local saturation temperature. After the first bubble-wall interaction, a microlayer tens of microns thick forms between the bubble and the wall; a thermal wake develops behind the bubble as it begins to slide against the wall. The predicted shapes, Re and Weber numbers and microlayer thicknesses show excellent agreement in comparison to experimental data from other researchers. Evolution of the flow and temperature fields were examined with the aid of contours of vapor volume fraction and iso-lines of mixture temperature superimposed on three-dimensional shapes of the bubble. Overall bubble dynamics and microlayer dynamics, including microlayer thickness and microlayer heat flux, are presented as functions of time. Using the wall, microlayer and wake heat transfer rates, an enhancement of the total wall heat flux was found to be on the order of 6 times the background heat flux. This work describes the bubble evolution through the first rebounding in detail, but the dynamic octree adaption algorithm lends itself to study of the long-term dynamics well into the sliding regime. The technique can also be used to investigate other multiphase flow phenomena — especially bubble coalescence and breakup.

Direct observations of radiation-enhanced transformations in glass

1983 ◽  
Vol 41 ◽  
pp. 354-355
Author(s):  
J. F. DeNatale ◽  
D. G. Howitt
Keyword(s):  
Glass Matrix ◽  
Diffusion Mechanism ◽  
Bubble Formation ◽  
Silicate Glasses ◽  
Phase Decomposition ◽  
Direct Observations ◽  
Thin Foils ◽  
Oxygen Bubble ◽  
Electron Energy Loss ◽  
Kinetics Of

The electron irradiation of silicate glasses containing metal cations produces various types of phase separation and decomposition which includes oxygen bubble formation at intermediate temperatures figure I. The kinetics of bubble formation are too rapid to be accounted for by oxygen diffusion but the behavior is consistent with a cation diffusion mechanism if the amount of oxygen in the bubble is not significantly different from that in the same volume of silicate glass. The formation of oxygen bubbles is often accompanied by precipitation of crystalline phases and/or amorphous phase decomposition in the regions between the bubbles and the detection of differences in oxygen concentration between the bubble and matrix by electron energy loss spectroscopy cannot be discerned (figure 2) even when the bubble occupies the majority of the foil depth.The oxygen bubbles are stable, even in the thin foils, months after irradiation and if van der Waals behavior of the interior gas is assumed an oxygen pressure of about 4000 atmospheres must be sustained for a 100 bubble if the surface tension with the glass matrix is to balance against it at intermediate temperatures.

Evidence for an Increased Generation of Prostacyclin in the Microvasculature and an Impairment of the Platelet α-Granule Release in Chronic Renal Failure

1988 ◽  
Vol 60 (02) ◽  
pp. 205-208 ◽  
Author(s):  
Paul A Kyrle ◽  
Felix Stockenhuber ◽  
Brigitte Brenner ◽  
Heinz Gössinger ◽  
Christian Korninger ◽  
...  
Keyword(s):  
Renal Failure ◽  
Chronic Renal Failure ◽  
Blood Clotting ◽  
Normal Subjects ◽  
Chronic Uraemia ◽  
Wall Interaction ◽  
End Stage ◽  
Granule Release

SummaryThe formation of prostacyclin (PGI2) and thromboxane A2 and the release of beta-thromboglobulin (beta-TG) at the site of platelet-vessel wall interaction, i.e. in blood emerging from a standardized injury of the micro vasculature made to determine bleeding time, was studied in patients with end-stage chronic renal failure undergoing regular haemodialysis and in normal subjects. In the uraemic patients, levels of 6-keto-prostaglandin F1α (6-keto-PGF1α) were 1.3-fold to 6.3-fold higher than the corresponding values in the control subjects indicating an increased PGI2 formation in chronic uraemia. Formation of thromboxane B2 (TxB2) at the site of plug formation in vivo and during whole blood clotting in vitro was similar in the uraemic subjects and in the normals excluding a major defect in platelet prostaglandin metabolism in chronic renal failure. Significantly smaller amounts of beta-TG were found in blood obtained from the site of vascular injury as well as after in vitro blood clotting in patients with chronic renal failure indicating an impairment of the a-granule release in chronic uraemia. We therefore conclude that the haemorrhagic diathesis commonly seen in patients with chronic renal failure is - at least partially - due to an acquired defect of the platelet a-granule release and an increased generation of PGI2 in the micro vasculature.

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