A simulation study of two-liquid flow in the taphole of the blast furnace

Abstract

An undisturbed drainage of molten liquids from the hearth through the taphole(s) is a prerequisite for smooth operation, with high productivity and long campaign life of the blast furnace. Along with growing blast furnace volumes and production rates the taphole load has significantly increased. Still, the flows of molten iron and slag in the taphole have not received much attention even though several investigators have studied the multiphase drainage phenomena of the hearth. In the present paper a three-dimensional computational fluid dynamics model is developed to study the transient flow behavior of iron and slag in the taphole. The interface shape between iron and slag is simulated by utilizing the volume of fraction method. A short-term tapping process is simulated and the developing flow patterns in the taphole are illustrated. It is demonstrated that both non-stratified and stratified flows can occur at different stages of the tap, where gravity plays an important role for the evolving two-liquid flow patterns. The results of the analysis also show that the slag-iron interface and phase velocity profile are reshaped along the flow direction. © 2013 ISIJ.