Bubble Coalescence, Foams and Thin Surfactant Films

2005 ◽  
pp. 153-171 ◽  
Keyword(s):  
Bubble Coalescence

Behaviour of air injection nozzles in dissolved air flotation

1995 ◽  
Vol 31 (3-4) ◽  
pp. 25-35 ◽  
Author(s):  
E. M. Rykaart ◽  
J. Haarhoff
Keyword(s):  
Bubble Coalescence ◽  
Second Phase ◽  
Initial Growth ◽  
Two Phase ◽  
Dissolved Air Flotation ◽  
Nozzle Orifice ◽  
Pressure Release ◽  
Air Volume ◽  
Air Flotation ◽  
Dissolved Air

A simple two-phase conceptual model is postulated to explain the initial growth of microbubbles after pressure release in dissolved air flotation. During the first phase bubbles merely expand from existing nucleation centres as air precipitates from solution, without bubble coalescence. This phase ends when all excess air is transferred to the gas phase. During the second phase, the total air volume remains the same, but bubbles continue to grow due to bubble coalescence. This model is used to explain the results from experiments where three different nozzle variations were tested, namely a nozzle with an impinging surface immediately outside the nozzle orifice, a nozzle with a bend in the nozzle channel, and a nozzle with a tapering outlet immediately outside the nozzle orifice. From these experiments, it is inferred that the first phase of bubble growth is completed at approximately 1.7 ms after the start of pressure release.

Bubble coalescence inhibition in volatile solutions at elevated temperatures

2016 ◽  
Vol 94 (7) ◽  
pp. 1413-1422 ◽  
Author(s):  
Jianbiao Shen ◽  
Jian Huang ◽  
Chuanping Liu ◽  
Li Wang
Keyword(s):  
Elevated Temperatures ◽  
Bubble Coalescence

Bubble coalescence in viscous liquids

1971 ◽  
Vol 26 (6) ◽  
pp. 839-851 ◽  
Author(s):  
J.R. Crabtree ◽  
J. Bridgwater
Keyword(s):  
Bubble Coalescence ◽  
Viscous Liquids

Bubble coalescence in foaming process of polymers

2006 ◽  
Vol 46 (5) ◽  
pp. 680-690 ◽  
Author(s):  
Kentaro Taki ◽  
Kazuhide Tabata ◽  
Shin-ichi Kihara ◽  
Masahiro Ohshima
Keyword(s):  
Bubble Coalescence ◽  
Foaming Process

scholarly journals A model of bubble coalescence in the presence of a nonionic surfactant with a low bubble approach velocity

2021 ◽  
Author(s):  
Yuelin Wang ◽  
Huahai Zhang ◽  
Tiefeng Wang
Keyword(s):  
Nonionic Surfactant ◽  
Surfactant Concentration ◽  
Bubble Coalescence ◽  
Bulk Concentration ◽  
High Concentration ◽  
Coalescence Time ◽  
Approach Velocity ◽  
Marangoni Stress ◽  
High Concentrations ◽  
High Concentration Range

A bubble coalescence model for a solution with a nonionic surfactant and with a small bubble approach velocity was developed, in which the mechanism of how coalescence is hindered by Marangoni stress was quantitatively analyzed. The bubble coalescence time calculated for ethanol-water and MIBC-water systems were in good agreement with experimental data. At low surfactant concentrations, the Marangoni stress and bubble coalescence time increased with bulk concentration increase. Conversely, in the high concentration range, the Marangoni stress and coalescence time decreased with bulk concentration. Numerical results showed that the nonlinear relationship between coalescence time and surfactant concentration is determined by the mass transport flux between the film and its interface, which tends to diminish the spatial concentration variation of the interface, i.e., it acts as a “damper”. This damping effect increases with increased surfactant concentration, therefore decreasing the coalescence time at high concentrations.

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