Mathematical Modeling of Flow and Heat-Transfer Phenomena in Glass Furnace Channels and Forehearths

A three-dimensional mathematical model was developed to calculate fluid-flow and heat-transfer phenomena in a channel/forehearth system used for delivering glass from the melting end to the forming end of a continuous-glass-fiber furnace. The model allowed for a varying cross section of the delivery system and for the temperature-dependent physical properties of the molten glass. Also, a formulation was presented to calculate heat transfer by radiation at the combustion gas/glass interface. The model was used to investigate the effects of natural convection, throughput, and radiation in the glass on velocity and temperature distribution in a glass delivery system. The results showed that, although the natural convection velocities were much lower than the average velocity due to throughput, the presence of natural convection significantly affected the flow path lines in the system. The results also illustrated the distribution of surface and bottom glass streams entering a channel into different forehearths.