FLOW-INDUCED BY AN ASYMMETRICALLY PLACED DISK ROTATING COAXIALLY INSIDE A CYLINDRICAL CASING

In this paper, the flow due to a rotating disk non-symmetrically place d with respect to the height of the enclosing stationary cylinder is a nalyzed numerically. The full Navier-Stokes equations expressed in ter ms of stream function and vorticity are solved by successive over-rela xation for different disk radii, its distance from the bottom casing a nd rotational Reynolds numbers. It is observed that the flow pattern i s strongly influenced by the size and the position of the disk. When t he disk is very close to the top casing and small in radius, there are two regions of different scales and the vortices in the region of sma ll scale are trapped between the disk and the top casing. Further, the variation of the moment coefficient is determined for different posit ions and sizes of the rotating disk. The calculations shows that the f rictional torque increases rapidly, when the disk approaches the top c asing. This finding is of importance for the design of vertical rotati ng disk reactors applied in chemical vapor deposition.