水中に侵入する球粒子上方に付着する気泡体積

抄録

An air cavity is formed behind a spherical particle immersing into a liquid bath. The residual bubble attached to the sphere has an important effect on the performance of CaO particle used for desulfurization of molted iron. In this study, the bubble volume behavior of air cavity was observed for the spheres coated by two kinds of water repellent preparations. In the preceding report, the volume of the residual bubble was estimated theoretically when the sphere is immersed into water quasi-statically. The system energy (i.e., work of wetting, potential energy and surface energy of gas-liquid interface) was calculated at the breakdown of the axi-symmetric meniscus and the bubble volume was determined from the energy minimum condition. Here in this report, the bubble volume was theoretically obtained for the sphere immersion with finite velocities (0.05～25mm/s). First the critical depth of the sphere at the breakdown of liquid meniscus was considered from a dynamic equation in which the movement of triple-phase contact line is analyzed from the energy gradient on the sphere surface. Then the bubble volume was estimated at the critical depth from the same energy minimum principle as that treated in the preceding report. The experimental results of bubble volume can be roughly approximated by the model proposed in this study.