Numerical Analysis of the Particle-Induced Effect on Gas Flow in a Supersonic Powder-Laden Oxygen Jet

The article addresses the particle-induced effect on gas flow by a developed mathematical model simulating the supersonic oxygen–limestone powder mixture jet from a newly designed, freely swinging oxygen lance for dephosphorization in a converter. The model was validated first and then employed to analyze the gas flow dynamics with respect to the jet structure, pressure wave sequence and velocity distribution, and particle motion behaviors over a range of powder particle sizes and mass flowrates. Numerical results reveal that the powder causes significant changes of the oxygen jet structure and weakens the pressure wave sequence outside the nozzle despite the higher gas flow static pressure of the powder-laden oxygen jet than that of the single-phase oxygen jet there. Furthermore, the powder creates nonuniform radial distribution of the gas velocity as an “M-type” curve and greatly restricts the gas jet flowing along the nozzle axis, which results in the smaller gas flow velocity but slower velocity attenuation. These phenomena become increasingly remarkable as the powder particle size is decreased or the powder mass flowrate is increased. The particles are accelerated but the acceleration declines gradually along the nozzle axis. The greater powder mass flowrate or particle size induces the lower particle velocity.