Flow characteristics and micro—bubble behaviour in a rotating pipe section with an abrupt enlargement

Abstract

The flow characteristics and dynamic behaviour of micro-bubbles were investigated experimentally and numerically for swirling flow within rotating pipe sections. In the present investigation, three types of rotating pipe section were used in order to study the effects of geometric configuration upon the flowfield. Experimental data were obtained for locations of the stagnation point and profiles of the parabolic surface. The results obtained from experiments were examined and verified with the aid of numerical analysis. It was found that the air pocket formed at the stagnation point was moved upstream by the effect of the suddenly expanded part when pipe rotation was increased. The reattachment point did not shift downstream as a result of an increase in the Reynolds number. This is due to the fact that the vortex zone at the expanded corner expands or shrinks, depending on the speed of rotation.