Numerical modelling of an industrial glass-melting furnace

The predictive capability of two comprehensive combustion codes, PCGC-3 and FLUENT, to simulate local flame structure and combustion characteristics i n an industrial gas-fired, flat-glass furnace is investigated. Model predic tions are compared with experimental data from the furnace for profiles of velocity, species concentrations, temperatures, and wall-incident radiative heat flux. Predictions from both codes show agreement with the measured me an velocity profiles and incident radiant flux on the crown. However, signi ficant differences between the code predictions and measurements are observ ed for the flame-zone temperatures and species concentrations. The observed discrepancies may be explained by (i) uncertainties in the distributions o f mean velocity and turbulence in the portneck, (ii) uncertainties in the p ort-by-port stoichiometry, (iii) different grid-based approximations to the furnace geometry made in the two codes, (iv) the assumption of infinitely fast chemistry made in the chemical reaction model of both codes, and (v) s implifying assumptions made in the simulations regarding the complex coupli ng between the combustion space, batch blanket, and melt tank. The study il lustrates the critical need for accurate boundary conditions (inlet air and fuel flow distributions, boundary surface temperatures, etc.) and the impo rtance of representative furnace geometry in simulating these complex indus trial combustion systems.