6.1 High speed tubular centrifuge
In case of high speed tubular centrifuge the velocity of the particle for size upto 10 micron does not perceptibility exceed 1 m/sec. The Reynolds number can be considered between 10-4 to 10 and this is the region where Stoke's law is applicable.
.......................................(5.20)
Above equation can be applied for high speed tubular bowl centrifuge. In this type of centrifuge the residence time estimated by V/Q introduces an error and because of that the performance evaluation on its basis may not be perfect. Another approach to evaluate the performance it to assume viscous flow in the bowl and use for its length some fraction of geometric length estimated empirically.
In case of a bowl of length L, having an internal wall radius rb. The bowl is filled so that the liquid surface radius is rL.
.................................(5.21a)
...............................(5.21b)
For the fallacious block flow pattern:
...................................................(5.22)