Design and calculation of gas property parameters for constant area lance under conditions of friction flow with heating

Formulae for calculating the outlet property parameters of gas heating and friction streams in tubular and annular type lances with constant area (tuy eres) are given, and have been applied to the case of an annular type used for an AOD (argon-oxygen decarburisation) vessel of 18 t capacity. The dist ributions of both the inner wall temperatures of the tuyere and the gas sta gnation temperatures along its length have been more reasonably fixed. The friction factors for the gas flows through the main and subtuyeres during b lowing refining have been determined by comparison of the practically measu red P-Q relationships with the results from trial calculations. The outlet parameters of the gas streams for the central tube (main tuyere) and annula r slit pipe (subtuyere) of the tuyere have been calculated. The influences of the gas supply pressure, the length and diameter of the tuyere, and the type and composition of the gases, as well as the heating effect, on the ga s outlet parameters have been considered. The results obtained may be expec ted to offer useful information and a reliable basis for tuyere design and determination, control, and optimisation of the gas blowing parameters and technology, as well as for the investigation of hydraulic modelling of the blowing processes. I&S/1440.