Effect of Coarse Aggregate Content on Bubble Formation Behavior in Corundum Permeable Brick for Tundish

Abstract

Herein, corundum porous permeable bricks with different coarse aggregate contents are prepared using particle packing method. Based on the similarity principle, a local water model of a tundish is designed to investigate the bubbling behavior in porous permeable bricks at various argon flow rates. Through dimensionless analysis, empirical formulas of bubbling region diameter and initial bubble size in porous permeable bricks are proposed. The results show that an increasing aggregate content can increase the apparent porosity and the proportion of large pores, reduce the surface fractal dimension of the porous permeable bricks, and obtain a higher gas permeability. With the increase of argon flow rate and the decrease of gas permeability, the internal pressure gradient in porous permeable bricks increases. The larger the argon flow rate and the gas permeability value, the more beneficial it is to activate more pores and form a larger bubbling region on the upper surface of porous permeable bricks. The Sauter mean diameter of bubbles and the initial velocity of gas plumes are inversely correlated with the content of coarse aggregate; that is, the porous permeable brick with a higher content of coarse aggregate is beneficial to generating much more small bubbles.