Α characteristic number of refining

Abstract

It was already reported about the prediction of the bubble population behaviour with numerical models based on the population balance model. On the basis of this model, the similarity of analytical function and numerical computation is now presented for some cases of refining. Under these simplified conditions the bubble size distribution of analytical and numerical computation is identical. It is possible to predict the refining time in dependence on the melting depth. In the first step the prediction is possible for laboratory crucibles and pots. The results were compared with experimental values. Some differences between experimental and theoretical refining time were interpreted assuming that the melt volume is homogeneous. This assumption is necessary for these investigations. Α homogeneous melt is found rather in small crucibles than in larger pots. Starting from the population balance model a characteristic (dimensionless) number was found for the refining of glass melts. This characteristic number concept gives some new points of view for a better understanding of the refining process. It shows the temperature dependence of refining time as temperature dependence of glass viscosity and bubble growth rate. The refining capability is described with a simple term. The value of refining capability can be determined by refining experiments. This value can also be calculated if the temperature dependence of glass viscosity and bubble growth rate is known.