Validation of an improved batch model in a coupled combustion space/melt tank/batch melting glass fumace simulation

Abstract

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. A 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.