COMPUTATIONAL MODELING OF TURBULENT-FLOW, COMBUSTION AND HEAT-TRANSFER IN GLASS FURNACES

For the combustion of natural gas in high temperature glass furnaces a computational model ''Furnace'' has been developed. It includes 3-D t urbulent flow, flame chemistry, radiative heat transfer and the format ion of soot and of the pollutant NO. Turbulent fluctuations have been taken into account, and are shown to have a large effect on thermal ra diation and NO-formation. Spectral behaviour of gas radiation results in changes of heat transfer efficiency up to 5%, depending on refracto ry emissivity. The model has been employed to predict NO formation for different burner geometries. In general, a decrease in mixing of gas and air results in a reduction of 1600 to 400 ppm in flue gas NO conce ntration. Except for some of the low mixing names, however, they lead to a lower burnout and a very high CO level in the flue gas. A compari son with semi-technical furnace tests shows that the model can predict NO formation reasonably well. With this computational model the desig ner of furnaces and burners can study further possibilities for increa sed furnace performance and low NO emissions.