Industrial & Engineering Chemistry Research, Vol.59, No.9, 4071-4078, 2020
Influence of Wettability on Bubble Formation from Submerged Orifices
The influence of wettability on the formation of a single air bubble at a submerged orifice has been investigated using computational fluid dynamic simulations in two-dimensional and three-dimensional geometries. The detachment times of the bubbles were observed. The bubble sizes were compared to those from experiments and those predicted from force balances. The simulations were able to predict the experimental results with an average deviation of less than 10%. The wettability of the orifice was varied in the simulations by varying the static contact angle of the orifice material for an air-water system. For hydrophobic orifice materials, the bubble size increases with increasing contact angle. The reason for this is that the gas entering through the orifice spreads partially along the wall, resulting in a larger force of adhesion as well as a larger area for the formation of the bubble.