Mass transfer around a rising bubble in a glass-forming liquid involving oxidation-reduction reaction: Numerical computation of the Sherwood number

Abstract : The mass transfer of a rising bubble in creeping flow regime is numerically investigated. A reversible oxidation-reduction reaction is taken into account. Two coupled equations are needed to study the oxygen and reduced species transport. Three dimensionless numbers are involved: the Péclet and Damköhler numbers and the ratio of the diffusion coefficient of the reduced species to the diffusion coefficient of oxygen. Numerical computations are applied to a soda-lime-silica and a borosilicate glass-forming liquids. Results are focused on the determination of the Sherwood number. The mass transfer enhances strongly when the chemical reaction is very fast, i.e. at large value of Damköhler number. Correlations to determine the enhancement factor are proposed in the two limits of small and large Péclet numbers. The Sherwood number enhances when the diffusion coefficient of the reduced species increases. A correlation of the Sherwood number is proposed taking into account advection and reaction.