Mechanism of mass transfer between a bubble initially composed of oxygen and molten glass
Résumé
The bubble removal from molten glass is an important problem in glass melting process. In this paper, the mass transfer undergone by a bubble rising in molten glass is studied, the multicomponent feature being taken into account. In order to identify the time scaling of the bubble shrinkage, a careful dimension analysis is performed. A characteristic time to describe the mass transfer for each gaseous species in a bubble is introduced with an alternative expression of the permeability. This new permeability has the dimension of a diffusion coefficient, which is useful to compare to other transport phenomena. From the physical data known for soda-lime-silica glasses, a fast equilibrium state of water between a bubble and molten glass is determined. The opposite situation is observed for nitrogen. Experimental results giving the bubble size versus time with a dimensionless form leads to a good match at short time whatever the glass nature and the temperature. Finally, a simple equation to determine bubble size as a function of time is given, based on the dimension analysis previously established.
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