CLSVOF simulations of H2 bubble rising through liquid metal bath covered with a thick slag layer

Abstract

Abstract The current study presents a fundamental understanding of the behavior of different-sized hydrogen bubbles rising in a new slag – metal system featured with a thick upper slag layer and ever-changing slag thickness and slag physical properties in the H2-based smelting process, based on newly developed CLSVOF model simulations. The evolution of bubble shape, bubble rising velocity, and the formation, collapse and detachment of metal liquid film wrapped on the bubble are predicted. The results show that decreasing the slag layer thickness or the slag viscosity delays the detachment of the metal liquid film from the bubble, increases the bubble rising velocity in the metal layer, but make no difference to the bubble terminal rising velocity in the slag layer. As a result, the bubble has shorter rising time in the bath with a higher slag viscosity. The resistance of the slag – metal interface to the bubble decreases with the increase of the bubble diameter, and small bubble therefore passes through the interface more slowly than the large one. In addition, the bubble shape evolution and bubble breakup in the slag layer are complicated with the increase of the slag thickness, bubble diameter and slag viscosity.