Prediction of unobstructed flow for co-rotating multi-disk drive in an enclosure

The flow structure and isotherms of hard disk drives (HDD) are investigated using a finite element method (FEM). The governing equations are based on the three-dimensional axisymmetric Navier-Stokes partial differential equat ions (PDEs) with Galerkin FE formulation. Go-rotating models are selected t hat include the non-ventilated configuration within an enclosure. With vari ous operating conditions for the disk system, the following important param eters are considered: disk number (n), rotational speed (Ro), and wall temp erature. The flow structure changes rapidly when the rotational Reynolds nu mber (Re-phi) is increased. The flow has a greater tendency to flow radiall y outwards and the swirling velocity tends to be more vertically orientated , especially for high Re-phi values. The isotherms only have small varying regions near the rotating axis, forming outward arcs near the wall and inwa rd arcs near the end gap of the disk. Different from the case without the e nclosure, the vorticities exist along the outer disk ends. Both the swirlin g velocity and isotherms indicate nearly symmetrical characteristics, as ex pected. A higher temperature gradient occurs near the right outer disk ends , which implies the characteristic of higher heat flux. A commercial comput ational fluid dynamic (CFD) code, CFX-5, was chosen to validate the results . Copyright (C) 2001 John Wiley & Sons, Ltd.