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- ItemValidation of an improved batch model in a coupled combustion space/melt tank/batch melting glass fumace simulation(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 2000) Wang, Jian; Brewster, B. Scott; McQuay, Mardson Q.; Webb, Brent W.An improved coupled combustion space model, model for the transport processes in the melting tank, and batch blanket melting model has been developed which is capable of predicting the transport phenomena in a float glass furnace. Model predictions are compared with experimental furnace measurements reported previously. The batch blanket has been approximated as continuous and discrete (island) regions in an attempt to simulate the formation of discrete batch clumps ("logs") observed in real furnaces. Both the boundary location between the continuous blanket and batch island zones, and the batch coverage fraction in the batch island zone are specified as model inputs. The heat fluxes and temperatures at the interfaces between the combustion space, the batch coverage, and the glass tank are calculated in a coupled fashion rather than assumed as input boundary conditions as it must be done in traditional, uncoupled models. Α 455-metric-ton pull rate per day, air-fuel fired float-glass melting furnace was simulated. The 100 % batch blanket simulation (absence of batch islands) yields over-prediction of glass surface temperature, crown incident heat flux, and crown temperature. The assumption of 85 % batch coverage and 15 % free glass surface in the batch island zone agrees well with most experimental measurements. The batch island concept added to the batch melting model is a significant improvement over previous approaches for this case.
- ItemPredicted and measured glass surface temperatures in an industrial, regeneratively gas-fired flat glass furnace(Offenbach : Verlag der Deutschen Glastechnischen Gesellschaft, 1999) Hayes, R. Robert; Wang, Jian; McQuay, Mardson Q.; Webb, Brent W.; Huber, Aaron M.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.