Viscous Frictional Moment between Eccentric Rotating Cylinders when Outer Cylinder Rotates

抄録

Although many studies on journal bearings have been reported as regards eccentric rotating cylinders, there is no frictional moment (torque) measurement which has been done for various eccentricity ratios and radius ratios in condition that there is sufficient fluid to fill the clearance in journal bearing. Recently, Oguro, Coles and Van Atta reported that under certain conditions a pattern of alternating helical stripes of laminar and turbulent flow could be observed in the gap between concentric rotating cylinders, with the outer cylinder rotating. However the critical Reynolds number has not been investigated in detail. In this paper the torque acting on the inner cylinder in eccentric rotating cylinders is measured over the range from the laminar flow to the fully developed turbulent flow, with the outer cylinder rotating. Torque measurements are done using water, glycerine-water solution and spindle oil, and increasing the fluid pressure in order to prevent the occurrence of cavitation. And we studied experimentally the relation between torque coefficient and a few parameters, such as rotating Reynolds number R_ω, eccentricity ratio etc., and obtained R_ω at which transition to turbulent flow occurs.