Evaluation of bubble removing Performance in a TV glass furnace : Part 1. Mathematical formulation

Abstract

The bubble evolution and dissolution process in a glass furnace is an extremely complicated physico-chemical phenomenon. Most of the huge number of bubbles, generated in molten glass during the decomposition of the glass batch, are removed during the trajectory from the charging end to the forming section, but some remain in fmal products. On the basis of the two mechanisms, flotation and absorption, in the bubble removing process, a numerical Simulator was developed to evaluate the influence of first, glass and batch composition, including refining agents, second, geometrical tank design and third, furnace operating conditions upon the bubble quality in products. In particular, the Simulator enabled the estimation of the effect of refining gases which are caused by decomposition of the refining agents. Furthermore, an index was devised to synthetically assess the numbers of bubbles in final products. In part 1, the principles of the model which composes the Simulator are described in mathematical formulation. The basic equations with boundary conditions and calculation procedures for thermal flow of molten glass, gas concentration in glass melt and gas evolvement from the refining agents are presented. The calculation strategy of the bubble removing process is also described.