Ceramics-Silikáty 49 (3) 162-169 (2005)

BEHAVIOR OF BUBBLES IN GLASS MELTS UNDER EFFECT OF THE GRAVITATIONAL AND CENTRIFUGAL FIELDS

L. Němec, V. Tonarová

Bubble removing during glass melting may be a slow process if only the gravitational force determines its rate. The chemical refining mostly supports the bubble growth and accelerated rising of growing bubbles through viscous melt. Other forces can be as well applied to enhance bubble separation from the melt as is the centrifugal force, surface forces or melt oscillations due to supersonic waves, e.g. The increasing effort for advanced melting principles during last period restored interest in bubble separation by centrifugal force. This work brings derivation of relations governing the one and multicomponent bubble behavior in a rotating cylinder. The mass transfer between the bubble and melt is taken into account, both discontinual and continual regimes of the cylinder are considered. The derived equations indicate a relatively complicated bubble behavior in the centrifugal field as the bubble separation velocity may be increased by the centrifugal force but the bubble growth by gas diffusion may be suppressed. The parametric study of the problem using appropriate glass and refining data is needed to appreciate the process properly.

Keywords: Glass refining, Bubbles, Modelling, Centrifugal forces