THE EFFECT OF ROTARY ARMS ON COROTATING DISK FLOW

This investigation studied the impact of rotary style arms on the flow between co-rotating disks contained by a stationary cylindrical enclosure. Both ventilated and nonventilated hub configurations were considered. The particular geometry used represents a simplified model for common disk drives. Flow visualizations were performed over the Reynolds number range of 3.4 x 10(4) to 3.4 x 10(5). The arms were observed to dramatically alter the flow field and to produce an azimuthal pressure gradient throughout the flow field. The dominant feature of the flow between two disks was the arm wake. Moreover, an exchange of fluid across the shroud opening, which provided arm access, was observed. Arm effects became stronger as the arm tips were positioned closer to the hub. The combination of arms and radial through flow was studied over a similar Reynolds number range. In this case, the flowfield remained dominated by arm effects, although some effects-arising from the radial flow were observed.