Calculation results and analysis of gas flow properties in tuyere under the influence of heat source

The flow properties of the gases in an annular-tube type tuyere used for an 18 t AOD vessel were analyzed using the equations and calculation formulas presented in Part I of this work. The influence of the heating and frictio n effects, the gas supply pressure, and the gas type and composition, on th e properties were examined. The results showed that the properties in a tuy ere are significantly changed due to the presence of a heat source. This ha s a similar effectiveness as increasing the friction action and obviously r educes the gas flowrate at the tuyere outlet. When designing a tuyere used in a practical process of metallurgy and calculating the flow properties of gas in the tuyere, the heating effect from the high temperature melt and r efractory lining should be taken into account. The gas supply pressure has a decisive effect on the properties. The type and composition of the blowin g gas will also influence the properties. For a given tuyere and blowing sy stem, appropriate blowing pressures for different gases, particularly for s ubtuyere gases, should be used according to the technological requirements of the different refining periods.