Experimental study of superlaminar flow between nonconcentric rotating cylinders

An experimental study was made of superlaminar flow in the annular space between a rotating inner cylinder and a close clearance stationary outer cylinder. The study included: (1) measurements of transition speed for onset of vortices at eccentricity ratios of 0.08, 0.2, 0.35, 0.51, 0.68 and 0.83, (2) measurements of rotational torque in the vortex and turbulent flow regimes over the range of Reynolds numbers from 200 to 4300, and (3) measurements of pressure profiles in the vortex and turbulent flow regimes over the range of Reynolds numbers from 400 to 3200. Critical speed for onset of Taylor vortices was found to increase with eccentricity, this increase being greater at higher clearance ratios than at lower ones. At C/R = 0.099, the critcial speed for onset of vortices at an eccentricity ratio of 0.7 was found to be 2.2 times greater than the critical speed for the case of concentric cylinders. At C/R 0.0104, the critical speed at E = 0.7 was 1.5 times greater than that for concentric cylinders. The measurements made of torque and pressure profiles in the Taylor vortex flow regime were compared with theoretical calculations based on an analysis by DiPrima (Ref. 1). When diPrima's analysis was modified to correct for the discrepancy between theoretical and measured Taylor critical speeds, the theoretical calculations of torque and pressure profiles agreed with measured values to within 10% for speeds up to 1.5 times the critical speed. Visual studies were made of vortex flow and turbulence in the flow between a rotating inner cylinder and an 80" partial arc outer cylinder. The critical speed for onset of Taylor vortices in the flow were found to agree with theoretical prediction by DiPrima (Ref. 4) to within 25%.