Shrinkage of an oxygen bubble rising in a molten glass

The mechanisms controlling the evolution of a bubble surrounded by molten glass are important to understand in order to improve melting in glass furnaces, particularly during a change in composition. In order to provide insight into this phenomenon, the behavior of an isolated bubble rising in molten glass is examined both experimentally and numerically.An experimental procedure developed specifically to observe, in situ, a rising bubble is described. Two soda-lime-silica compositions are tested, with low and high iron content, respectively.The numerical model used to describe bubble shrinkage is based on the results recently proposed in Pigeonneau (2009). A specific mass transfer coefficient is used for oxygen where the oxidation–reduction reaction of iron oxides is taken into account.A comparison between the experimental and numerical results shows the importance of the oxidation–reduction reaction of iron in the mass transfer of oxygen. The shrinkage rate of a pure O2 bubble is enhanced with reduced molten glass iron content.