Effect of Nozzle Exit Wear on the Fluid Flow Characteristics of Supersonic Oxygen Lance

Supersonic jet characteristics of oxygen lance nozzles have a significant influence on smelting; however, presently, little research has been carried out to investigate the influence of wear on the jet characteristics at the nozzle exit. A numerical model and aerodynamic testing platform were developed to analyze supersonic jet characteristics under different inlet pressures and wear levels at the nozzle exit. The numerical model was first validated by comparing the numerical results with the measured data of the aerodynamic testing experiment. Then, the effects of the inlet pressure and nozzle exit wear on the jet velocity and degree of aggregation were studied. An increase in the nozzle inlet pressure is conducive to an increase in jet velocity but also causes earlier jet convergence. An increase in the nozzle exit wear results in the faster attenuation of jet velocity, not only reducing the jet velocity but also leading to an earlier convergence point for each jet. The results of this study can provide theoretical support for the design of an oxygen lance nozzle and process optimization of smelting in industrial application.