Glass Melt Quality Optimization by CFD Simulations and Laboratory Experiments

Abstract

The quality of a glass melting process is determined by the melting in performance, the sand grain dissolution and the removal of gas bubbles by fining. For good quality it is essential that each trajectory/path starting from batch charging to the throat or waist of the tank shows complete melting and fining. Each part of the glass melt should be exposed to temperatures such that fining can occur. The fining onset temperature and melting performance for an industrial glass tank depends on the batch composition, sand grain size, type and amount of fining agent, furnace atmosphere and the redox number of the batch. Laboratory experiments are carried out to determine the most important parameters for industrial batches. The results of these laboratory experiments are used as input to the CFD (Computational Fluid Dynamics) model GTM X, which then provides the temperature and flow fields in the industrial melting tank, along with the calculation of the individual glass melt trajectories. This combination of experiments and CFD simulation proves to be a very powerful tool for determining the fining and melting performance of industrial furnaces. Special attention will be paid to the location of the fining zone, with respect to the convection flows in the melt.

Modeling batch melting: Roles of heat transfer and reaction kinetics

“…Nevertheless, estimating the melting rate based on the heat‐transfer properties of the batch blanket still dominates the commercial CFD market of glass melter models, being used by many companies worldwide . This is because implementing the heat transfer model is relatively simple, and because when such a model is validated by operational data from a particular plant, it provides acceptable boundary conditions for the CFD model of the molten glass below to resolve the molten glass flow and temperature in the furnace.…”

A Shielding System Proposal for the Cabling of Electric Glass Melters

“…There is little published data on simulation of furnaces for glass production and directed mainly to the modeling of current temperature and flow fields inside the furnace [8]- [12]. The most complex simulation requires a three-dimensional CFD-type calculation code [13], [14] and one of the main open problems concerns the knowledge of the electrical characteristics of the glass as it varies in temperature and composition. Even just the resistivity depends on these parameters and it is not easy to find in literature closed formulas that provide this parameter.…”

Viscosity of glass‐forming melt at the bottom of high‐level waste melter‐feed cold caps: Effects of temperature and incorporation of solid components

“…A lack of relevant data and insufficient understanding preclude the development of plausible simplifications that would yield results correlated with technological experience. Models of commercial glass-melting furnaces, although their development dates back several decades [16][17][18][19][20][21][22][23][24][25][26][27] -including those in wide commercial use, such as Glass Furnace Model-GFM ® (developed by Glass Service) and GTM-X ® (developed by Celsian Glass BV)-are no exceptions. Figure 1 illustrates some features of the complex structure of the feed-to-glass conversion zone.…”