Improvement of gas entrainment evaluation method; Introduction of surface tension effect

Ito, Kei; Eguchi, Yuzuru*; Monji, Hideaki*; Ohshima, Hiroyuki; Uchibori, Akihiro ; Xu, Y.*

A gas entrainment (GE) evaluation method presented at the previous symposium can predict a gas core length by applying local instant values (obtained from CFD results) to the extension vortex theory. However, in the GE evaluation method, a surface tension effect was not introduced. Therefore, it is valid to consider that gas core lengths were overestimated. In this study, the prediction accuracy of gas core lengths is improved by introducing the surface tension effects into the GE evaluation method. For that purpose, the mechanical balance between gravitational, centrifugal and surface tension forces are considered. The improved method was validated by predicting the gas core lengths in basic experiments. As the results, the predicted gas core length values by the improved evaluation method gave better agreements with the experimental results than the original evaluation method.