PIV study of the flow across the meridional plane of rotating cylinders with wide gap

Abstract

This study investigates by Particle Image Velocimetry (PIV) the wavy Taylor vortex flow that develops in the gap between concentric rotating cylinders of low aspect ratio and low radius ratio, which is a configuration relevant to oil bearing chambers in turbomachinery. The configuration is characterised by a larger annular gap width than in classical journal bearing and by a Taylor number (Ta) of 2.47 × 106, which is 1000 times higher than the first critical Taylor number. It is found that the non-uniform axial spacing of the vortex cores induces an asymmetric radial velocity profile and an inflected axial velocity profile close to the cylindrical walls. The outflow at the centre of each pair of Taylor vortices that make up a vortex cell is strong and it is characterised by a sharp radial velocity peak. The inflow between pairs of Taylor vortex cells is unconventional in that it is characterised by pairs of confluent streams from the outer cylinder that merge towards the inner cylinder. These results form a body of experimental evidence on the flow features that may occur in engineering practice in oil bearing chamber flows, with relevance to lubrication and wear.