Cold Model Experiment on Entrapment of Inclusions in Steel by Inert Gas Bubbles

Abstract

Cold model experiments have been done on entrapment of inclusions in steel by inert gas bubbles. A water-air system has been adopted and the teflon, polystyrene, polyethylene, polypropylene and polycarbonate particles( dia.= 100800 μm, ρ_p= 0.892.2 g/cm³) were used in the experiments. The collision-trapping rates V(n_p/cm³s) of various particles with bubbles were measured, and the effects of water-particle contact angle, φ, the particle diameter, d_p, the bubble diameter, d_b, the particle density, ρ_p and the frequency of bubble which passed through a unit volume of water have been investigated.
It is found that V increased with increasing φ, and there is a critical φ_c above which the V is independent of φ, and in this case the bubble surface resistance can be neglected in the collision-trapping process.
The particle mass transfer coefficients k (cm/s) have been measured under the condition that the surface resistance could be neglected, and an equation of the relation between k and db, d_p and ρ_p has been obtained.