An Air Cavity Formed Behind a Poorly Wetted Sphere Penetrating into a Water Bath

Abstract

Uniform dispersion of fine particles of poor wettability in molten steel is of essential importance for enhancing the efficiency of the steel refining processes. Although model investigations on the dispersion of fine particles of good wettability have extensively been carried out, those for fine particles of poor wettability are rather limited. In this study the behaviors of three kinds of solid spheres penetrating into a water bath were observed with a high-speed video camera. The wettability was changed by coating hydrophilic or hydrophobic material. The well-known crown was formed behind a solid sphere of good wettability, while an air cavity was formed behind a solid sphere of poor wettability. Empirical equations were derived for some parameters describing the shape and size of the cavity.