Modeling of supersonic jet behavior in the vacuum refining process

Abstract

There are two problems to be solved in the numerical simulation of the top blown oxygen vacuum refining process. (1) The two-equation turbulence models underpredict the turbulence mixing shear process for high-temperature gradient jet flows. (2) The high compressibility of the jet in a low vacuum environment. In this study, the SST k-ω turbulence model is modified by the composite function of the compressibility factor and the total temperature gradient. Based on the experimental model of the Kotani vacuum jet, the modified turbulence model was used to simulate the supersonic jet behavior of oxygen lance at different ambient temperatures. The reliability of the model is verified by the semi-empirical formula of Ito and Muchi. The simulation results show that the entrainment rate is an important inducing factor. The potential core length and the supersonic core length at the temperature of 1800 K are 2.5 times and 2.0 times that at the temperature of 285 K, respectively. Besides, based on the ejection model established by Ricou and Spalding, the calculation formula of turbulence entrainment rate at different ambient temperatures is obtained. This research work will benefit greatly to the supersonic jet behavior in Vacuum Refining.