Numerical Study of Droplets: Hydrodyamics in Oxygen Steelmaking.

Abstract

An attempt is made to study some fundamental aspects of rising gaseous bubbles (liquid-gas) in stagnant Newtonian liquids using a Volume of Fluid (VOF) method. After successful validation this model is applied for liquid-liquid system (molten metal-slag). For low value of Eotvos number/Reynolds number (Eo ≈ 1/Re≈ 1) terminal shape of rising bubble remains constant. As the bubble size increases or intermediate value of Eotvos number/Reynolds number (1 < Eo < 100/1 < Re < 100), the shape of bubble is significantly affected because of fluid properties. In this range various bubble shape such as ellipsoidal, skirt and spherical cap bubble shapes are formed. For higher value of these dimensionless number (100 < Eo < 200 / 100 < Re < 200) bubble shape turn out to be more toroidal. When the value of Eotvos number/Reynolds number lie in between (30 < Eo/Re < 100) bubble shape turns in to spherical cap bubble shape and for 100< Eo < 200 bubble changes in to oblate ellipsoid bubble. For higher value of Eotvos number/Reynolds number (Eo/Re>500) wake formation will be more and bubble leads towards the instability. In addition, rising velocity of bubble also calculated for three different size (3, 4 and 5 mm) of bubble and compared with the results which is obtained from available correlations. After that effect of ejection angle and diameter studied for droplet motion in basic oxygen steel making process and also studied behavior of droplet in different type of slag. The continuity, momentum and volume of fluid fraction equations were solved using the ANSYSFLUENT (version 15), which is based on the finite volume method. The pressure implicit with splitting operators (PISO) algorithm was applied to solve the pressure-velocity coupling. The present work of air bubble/droplet rise behavior was well agreement with available literature results.