CFD Study on Improving RH Degasser Flow Using Combined Up-Snorkel and Side Gas Blowing

The production of high-quality steel in a shorter treatment time requires efficient circulation in the Ruhrstahl–Heraeus (RH) vacuum degasser. Despite previous studies on RH vacuum refining, limited attention has been given to the combined influence of up-snorkel gas blowing and side-nozzle blowing conditions. A VOF-Lagrangian multiphase numerical model was developed based on an 80-ton water-air based RH model (1:4.8 similarity ratio) to simulate multiphase flow, with a focus on side-blowing through additional nozzles placed at 30°, 45°, and 60° in the vacuum chamber. Gas injection rates up to 19 L/min were considered, with a combined setup of 17 L/min through the up-snorkel and 2 L/min through side-blowing nozzles. The model captures interactions between Lagrangian-tracked air bubbles and the free water surface. The CFD simulations examined the effects of side-blowing angles, circulation flow rate, and flow patterns. The simulation results were compared to experimental data obtained from the water-air physical model, showing close agreement with the experimentally measured value. Results indicate that the side-blowing configuration provides the Compared to conventional up-snorkel-only blowing, the optimised combined approach offers higher circulation rates. This study demonstrates that a carefully designed side blowing injector alongside a combined flow rate at the up-snorkel and side blowing at the vacuum chamber strategy can significantly improve RH operational efficiency in steel production.