Flow patterns in breaking bubbles

Mechanisms of Iron Entrainment into Slag due to Rising Gas Bubbles.

“…Is this really possible? As reported by MacIntyre, 13) once a bubble film breaks, it expands with a maximum velocity of the order (2s/rh) 1/2 , independent of the hole diameter. By and large, a hole in a 2-mm-thick iron film spreads at about 17 m/s when its surface tension is about 1.2 N/m, while the rising velocity of a gas bubble in liquid iron is about 1.2 m/s.…”

“…Firstly, when a bubble bursts on a free surface of a liquid, the cavity collapses in such a manner that a layer of fluid flows down the cavity wall preceding the toroid movement, as the liquid converges at the bottom of the cavity, a jet is created. 13) However, when a bubble bursts at the slag/iron interface, the surface of the cavity is under the pressure of the gas bubble, which makes the formation of a jet more difficult than in the case without that pressure, because more energy will be consumed on the friction between the shear flowed layers. Secondly, when a bubble bursts on the free surface, the rapid movement of the toroidal rim helps the jet formation, 13) but when a bubble bursts at the slag/iron interface, the frictional energy consumed between the iron film and the slag retards the movement of the toroidal rim and thus impedes the iron jet formation.…”

“…13) However, when a bubble bursts at the slag/iron interface, the surface of the cavity is under the pressure of the gas bubble, which makes the formation of a jet more difficult than in the case without that pressure, because more energy will be consumed on the friction between the shear flowed layers. Secondly, when a bubble bursts on the free surface, the rapid movement of the toroidal rim helps the jet formation, 13) but when a bubble bursts at the slag/iron interface, the frictional energy consumed between the iron film and the slag retards the movement of the toroidal rim and thus impedes the iron jet formation. Therefore, the kinetic energy from the wake of the bubble will have the decisive influence on the formation of the jet.…”

Chemical characterization of cloud episodes at a ridge site in Tuscan Appennines, Italy

“…Film drops, jet drops and shearing drops originating from strong winds can evaporate to give aerosol particles. Adsorption of natural and man-made surfactants [surfactant organic matter (SOM)], on the surface of bubbles, also heavily increases the concentration of pollutants, which are able to interact with them, for example, heavy metal ions (MacIntyre, 1972;Blanchard, 1975;MacCarthy, 1989;Frimmel and Abbt-Braun, 1993;Cini and Loglio, 1997;Cini et al, 1998;Oppo et al, 1999).…”

Damage mechanisms of suspended animal cells in agitated bioreactors with and without bubble entrainment

“…Practically, the cells are damaged by the breakup of the bubbles used to oxygenate the bioreactor, and breakup and cell damage take place almost exclusively (Michaels et al, 1996) on the free liquid surface of the bioreactor. This mechanism of bubble-breakup was already reasonably understood (Macintyre, 1972) to allow estimation of the forces experienced by cells attached to the bubble (Papoutsakis, 1991a), but the detailed understanding of these forces came 3 years later (Boultonstone and Blake, 1993). In addition to understanding the parameters that affect the velocity of the collapsing bubble surface (Michaels et al, 1995a), understanding the process of how cells attach to bubble surfaces Chalmers and Bavarian, 1991;Michaels et al, 1995b) and how strongly was most valuable.…”