Computational Modeling of Bubble Formation on Submerged Orifice

Abstract

This paper presents the computational study of air bubble evolution and disengagement in water from a single nozzle (1mmdiameter) underwater with an airflow rate of 2 mL/min using the VOF method with the LS method coupled. We have investigated the bubble evolution at different contact angles ($50^{ \circ } \le \theta_{0} \le 110^{ \circ }$ at solid–liquid–gas interface. We examined the variation of bubble volume (V) at different contact angle and size of the bubble at the base (D) and we investigate the stages of growth of bubble termed as (1) nucleation period, (2) under critical growth, (3) critical growth, and (4) necking, during bubble rising or evolution. I saw in my study that the bubble volume depends on the wetting condition and bubble volume increases drastically as contact angle varied $\theta_{0}$, changes from $50^{ \circ }$ to $110^{ \circ }$. Bubble evolution is beginning to be regulated by the hysteresis of contact angle. During the expansion stage and elongation stage of the bubble, bubble shape oscillates which was observed in my simulation. In the initial rise of bubble surface tension, capillary force is dominated and variation of viscous drag force is neglected.