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

Abstract

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-resolved glass surface temperature measurements were performed during the approximately 20 s reversal period of the furnace. The measured glass surface temperature data are supplemented by observations of the batch location using a specially designed, water-cooled video probe. The average temperatures were found to rise from a low near 1700 Κ near the batch blanket to a peak of approximately 1900 K, then drop to a level of 1800 K. Evidence of batch Islands or "logs" is observed in the surface temperature data collected at the measurement location nearest the batch blanket. Large temperature excursions are seen here, indicative of measurement alternately of both the batch surface and the molten glass. Also reported in this study are results of a numerical model for the three-dimensional melt flow and heat transfer in the tank, coupled with a batch melting model. The radiant heat flux distribution incident on the melt and batch blanket surfaces is assumed. The melt tank model includes bubbling. The numerical predictions agree well with the timeaveraged glass surface temperature data collected experimentally The measurements and model predictions illustrate the complex transport phenomena in the melting section of the furnace.