Bubble evolution and necking at a submerged orifice for the complete range of orifice tilt


Correspondence concerning this article should be addressed to P. K. Das at pkd@mech.iitkgp.ernet.in.


Bubble formation at an inclined orifice has been studied numerically using coupled-diffused interface-smoothed particle hydrodynamics. The simulation covers the entire range of orifice inclination, starting from upward facing (0°) to downward facing (180°) orientation for a moderate air flow (30 cm3/s). Bubble at the orifice mouth becomes asymmetric as the plate gets tilted. The asymmetry maximizes at vertical orientation but with downward facing orifices symmetry restores. The local hydrodynamic structure reveals that the internal circulation cells in bubble become stronger as the inclination increases making the growing bubble asymmetric. Interestingly, bubble volume for downward facing orifice is 4.75 times higher than the bubble released at upward facing orifice. Observations from the present simulations suggest that bubble frequency and shape can be controlled by allowing appropriate inclination in the orifice mouth. © 2012 American Institute of Chemical Engineers AIChE J, 59: 630–642, 2013