2-PHASE FLOW IN AN ANNULUS WITH A ROTATING INNER CYLINDER (FLOW PATTERN IN BUBBLY FLOW REGION)

The two-phase flow pattern in a concentric annulus with a rotating inn er cylinder have been investigated experimentally. The observed flow p atterns were dispersed bubbly, ring-form, single-spiral, double-spiral , triple-spiral flows and transition regions. When the rotational spee d was at a relatively low level, the buoyancy effect of bubbles domina ted the flow field and a dispersed bubbly flow was formed. On the othe r hand, when the rotational speed was at a high level, the vortex moti on induced by the rotation dominated the flow field and ring-form and spiral flows were formed.