Experimental Investigation of Planar Wake, Accelerated and Decelerated Flow in a Rotating System Mounted in a Non-axisymmetric Configuration with Inserted Obstruction

抄録

Rotating flow in corotating systems is modelled using non-axisymmetric configuration with inserted obstruction (arm) and a partial shroud opening. These kinds of systems exist in artificial hearts, turbomachinery, and hard disk drive (HDD), and they exhibit three-dimensional structure and fluid shear within their enclosed casing. In our study, we applied 2D-2C particle image velocimetry (PIV) to investigate planar flow physics in the model which portrayed an HDD used for information storage. While the flow has been extensively investigated in simplified axisymmetric models, there is a lack of sufficient results for non-axisymmetric configurations that more accurately represent conventional HDD geometries. Varying the inseretion angle of the arm between shallow and deep configurations, and at three measurement planes in the inter-disk 𝑟 − 𝑧 plane, the flow pattern exhibited different behaviour depending on the region upstream or downstream the inserted arm. Downstream, the flow transitioned at a critical radius (𝑟𝑐∗ ) between solid body rotation towards the edge of the hub and a sheared flow towards the edge of the disk. At the hubarm constricted region, an accelerated flow was formed with the deep arm insertion velocity matching, and exceeding disks local velocity further downstream, but the shallow insertion maintained a full solid body rotation towards the edge of the hub. At the upstream region of the inserted arm, a distinct pattern of the flow revealed a deceleration pattern.