The quantity space utilisation of a glass-melting space was introduced with the intention of evaluating the impact of glass-flow character on the processes of sand dissolution and bubble removal in a continual melting space. Different glass-flow patterns in the model horizontal melting channel were produced by linear temperature gradients applied on the glass level. In addition, the maximum sand-dissolution or bubble-removal performances of the space were calculated by mathematical modelling. The combination of a transverse and small positive longitudinal temperature gradients, which resulted in spiral melt and bubble trajectories, showed the best values of the space utilisation for both processes, even higher than had been attained under conditions of uniform melt flow. The values of space utilisation, linearly proportional to the melting performance, showed typical maxima when plotted as a function of the ratio of the transverse and longitudinal temperature gradients. The positions of the maxima and their values are discussed with respect to the ratio between the gradients and the intensity of the circulation flows. The application of the optimal flow character in glass-melting furnaces appears to be promising for process optimisation; an increase of the melting performance or a miniaturisation of the melting space and decrease of the energy consumption of the melting process.
