Effect of Drag Laws and Turbulence Models on CFD Modeling of the Bubble Behavior and Fluid Flow in RH Reactor

Different drag laws and turbulence models were compared to evaluate gas distribution and fluid flow velocities in a Rheinstahl–Heraeus (RH) reactor. The discrete phase model was adopted to track injected gas bubbles, and the volume of fluid model was applied to describe a more actual free surface. The prediction accuracy of the numerical model was evaluated by the measured flow velocity in an air-water model and the measured circulation flow rate of molten steel in a real RH system. Results indicate that Morsi’s drag law predicts more accurate local velocity compared with Schiller’s and Harmathy’s laws. The influence of turbulent dispersion on the injected gas bubbles is non-negligible for predicting the gas–liquid flow in a RH reactor. In addition, although the large eddy simulation (LES) approach predicts more actual free surface fluctuation, the realizable k-e model shows better agreement with the measured local velocity in the furnace.