Enhancement of Recirculation Process for RH Degasser Steel Making Through Bottom purging Inert Gas: A CFD based Investigation

Abstract

A comprehensive numerical based simulation of flow behaviour of molten steel inside the steel ladle and RH degasser has been investigated using Computational Fluid Dynamics (CFD). Modelling of flow behaviour of liquid steel in the vacuum chamber, up snorkel, down snorkel and steel ladle is very important to produce quality of steel and IF steel. Investigation of metal recirculation in ladle and vacuum chamber using bottom purging is the objective of this thesis work. In the present modelling ANSYS 18, FLUENT solver is used and the work done is for single phase and CFD based modelling. The modelling is done by using energy on, transient condition and we are using k-epsilon equation for the simulation. For the analysis, we are using iteration graph to insure that model is in study state. Other four graph i.e. velocity vector, path line, streamline and velocity volume rendering is used to steady the flow behaviour in different region. For this investigation the argon gas injection velocity from ladle bottom is variable and other parameters like up snorkel argon injection velocity is 0.000111m/s and total vacuum vessel pressure is 150 Pa are constant throughout the study. In the present study it is found that ladle argon injection velocity greater than a critical velocity will stop the recirculation of metal in RH degasser. Injection velocity less than critical velocity will support the recirculation of liquid metal in RH degasser. For minimize the process time ladle bottom argon injection velocity should have optimum value. Injection velocity grater then optimum velocity will decrease the metal recirculation in RH degasser, velocity less than optimum velocity will decrease the recirculation in ladle and both will increase process time