Influence of low-frequency vibrations on bubble and drop sizes formed at a single orifice

Abstract

We have studied the influence of low-frequency vibrations of the water phase, in the 50–400 Hz range, on the size of air bubbles and oil drops formed at a single orifice. A special device, called a vibration exciter, is mounted at the bottom of the column of 0.1 m diameter, filled with water. The vibration is transmitted to the water phase by means of a piston. Both the amplitude of the vibration and its frequency can be adjusted accurately. Air, or paraffin oil, is injected through a single capillary orifice into the column at a precisely controlled flow rate. The number of bubbles, or drops, issuing from the orifice is determined accurately by video imaging techniques. Application of vibrations to the water phase is seen to reduce the size of the air bubbles by 40–50% and that of the oil drops by 70–80%. It is concluded that application of low-frequency vibration has the potential of improving contacting in fluid–fluid dispersions.