Effect of Shrouding Gas Parameters on Characteristics of Supersonic Coherent Jet

Supersonic coherent jet plays a vital role in the steelmaking process; its impact force and stirring ability determine the smelting process. Many researchers have studied the characteristics of coherent jet under different shrouding fuels and oxygen flow conditions, but the preview results cannot reveal the relationship between the shrouding gas temperature, pressure, density, and the flow filed of coherent jet. In this paper, the field characteristics of coherent jet and conventional supersonic jet under different shrouding gas parameter conditions are studied by numerical simulation and experiment. The result shows that the temperature and pressure of the nozzle exit are affected by shrouding gas and it leads to the velocity and temperature fluctuations of the supersonic jet. The high temperature, high speed, and low density environment produced by shrouding gas protect the supersonic jet, and reduce the radial expansion and the axial velocity attenuation rate of the jet. The relationship between the supersonic region length of jet and the shrouding gas parameter is proposed. Compared with the conventional supersonic jet, the distributions of half-jet width and the position of vorticity magnitude are changed by shrouding gas. With the high temperature, high pressure, and low density of the shrouding gas, the turbulence intensity of the jet maintains a low level in a longer distance.