Flow Between Eccentric Rotating Cylinders, Where the Clearance is Relatively Large

Abstract

Measurement of viscous frictional moment and a visual study of flow between eccentric rotating cylinders, of which the outer one rotates, are done for the relatively large clearance ratios. Friction factors are considered for various eccentricity ratios in the laminar, the transient and the fully developed turbulent flow region, respectively. In the fully developed turbulent flow region, friction factor C_M can be given by C_M^∝ R_ω^-0.3 for various eccentricity ratios m. In the transient region where a turbulent spot or a spiral turbulence is observed, the oscillatory change of friction factor can be measured. But such an oscillation is damped, as the flow becomes fully turbulent. Critical Reynolds number decreases significantly with an increase of eccentricity ratio.