Ceramics-Silikáty 49 (4) 269-277 (2005)

THE BUBBLE DISTRIBUTION IN GLASS REFINING CHANNELS

L. Němec, P. Cincibusová

Equations were derived describing bubble distribution in horizontal, inclined and vertical channels with glass melt where bubbles behave as independent objects. The melt plug flow, as well as melt flow characterized by the parabolic velocity profile were considered in mentioned derivations. Using data typical for glass melting and fining, the bubble number and volume densities were calculated in a horizontal and vertical channels with downward plug flow. The bubble concentration profiles in the horizontal channel showed an almost permanent decrease of bubbles with time, while the vertical channel exhibited the bubble accumulation in the area where bubbles in downward flowing melt started to rise because of their growth. The concentration of bubbles in this area was at least by order of magnitude higher compared to bubble input concentration. This fact has both technological and theoretical consequences: coalescence should play a significant role in the accumulation area and convection currents could develop. The model considering the mutual influence of melt and bubbles should be applied.

Keywords: Glass fining, Bubble distribution models, Horizontal channel, Vertical channel