Single Bubble Chain Behavior and Liquid Flow Structures in the Vicinity of a Nozzle (Liquid Jet Developments by Single Bubble Chains)

Abstract

The behavior of single nitrogen gas bubble chains and the structures of flow field in the vicinity of a nozzle were experimentally studied. Both bubble diameters and bubble generation frequencies were precisely controlled independently to be 2.2 mm, and from 1 Hz to 10 Hz (corresponding bubble distance ; 300∼30 mm), respectively, by using innovative acoustic device. Careful investigations of flow field in the vicinity of a nozzle by using Particle Image Velocimetry enabled us to investigate the following two significant physical phenomena. First, The lift forces acting on bubbles in the bubble chains were observed to increase as bubble generation frequency increases, and were largely affected by the preceding bubbles. Second, developments of characteristic liquid jet were identified to play a dominant role in generation of lift forces on each bubble in single bubble chains, and were theoretically investigated by applying the conservation of liquid momentum.