Impacts of radiation heat transfer on NOx calculation in industrial furnaces

A computational glass furnace model was developed for the glass industry to evaluate the glass furnace performance. GFM simulates the major flow and heat transfer characteristics in both the combustion space and glass melter of the furnace, including fluid mixing, combustion, soot/NO_x formation and transport, radiation heat transfer, batch melting, and glass flow. A computational fluid dynamics code is used to simulate the combustion space flow including NO_x formation and transport, and spectral radiation heat transfer from soot, gaseous species, and walls. Major features of the model include the time-integral lumped oxy-fuel combustion model and direct integral solution of spectral radiation transport equation. The furnace model has been validated with experimental data from commercial glass furnaces. Radiation heat transfer in a furnace includes three major components: emission from soot and gaseous species, absorption of these species, and emission/reflection of the surrounding walls. The results of a parametric sensitivity study show that the radiation heat transfer components have significant impacts on the calculation of the gas temperature and NO_x.