Predicted and measured glass surface temperatures in an industrial, regeneratively gas-fired flat glass furnace

This study reports optically measured glass surface temperatures along the furnace center-line in the combustion space of a sideport, 455 (metric) t/d industrial, gas-fired flat glass furnace. The measurements were made using a water-cooled two-color pyrometer inserted through holes in the crown at six locations along the length of the furnace. Both average and time-resolv ed glass surface temperature measurements were performed during the approxi mately 20 s reversal period of the furnace. The measured glass surface temp erature data are supplemented by observations of the batch location using a specially designed, water-cooled video probe. The average temperatures wer e found to rise from a low near 1700 K near the batch blanket to a peak of approximately 1900 K, then drop to a level of 1800 K. Evidence of batch isl ands or "logs" is observed in the surface temperature data collected at the measurement location nearest the batch blanket. Large temperature excursio ns are seen here, indicative of measurement alternately of both the batch s urface and the molten glass. Also reported in this study are results of a n umerical model for the three-dimensional melt flow and heat transfer in the tank, coupled with a batch melting model. The radiant heat flux distributi on incident on the melt and batch blanket surfaces is assumed. The melt tan k model includes bubbling. The numerical predictions agree well with the ti me-averaged glass surface temperature data collected experimentally. The me asurements and model predictions illustrate the complex transport phenomena in the melting section of the furnace.