No Not the forced vortex finder. Actually if you study the flow pattern in hydrocyclones, two kinds of vrtices are developed. The free vortex and the forced vortex. the forced vortex envelops the air core. I am not sure how thiss forced vortex helps in classification of particles. I would like to know this
Hydrocyclone performance has been described
by empirical formulas and charts. The leading
vendor has done well for itself by stressing
anticipated customer conditions in making application
reccommendations. BUT, there is a lot wanting in a
hydrocyclone. The reason that it is a staple in mining
is because of its capacity and simplicity. Also, it
melds the necessary unit operation of slurry pumping
required for the next unit operation with the unit operation of size classification.
So we may understand each other, the met./ min.proc.
community describes three key parts of the hydrocyclone.
The inlet is obvious. The vortex finder is adjacent the
inlet and admits the bulk of outflow from the unit. The
apex is at the "base" and is at the opposite end from the
other two ports. Obviously, the inlet flow vortex proceeds
to the vicinity of the apex. But simple displacement, the
helical flow must reverse course near the apex and flow
in the opposite direction to exit out the vortex finder.
The apex is usually of smaller diameter than the vortex
finder, so the bulk of the flow must exit this port. The
spinning action doesn't change the phenomena of fluid displacement.
Now, the fluid flow arrangement is the setting by which
particle separations occur. Particle size, PARTICLE SHAPE,
pulp density, water temperature, particle size distribution
and salinity all affect performance. Simply put, these conditions affect what "spins out" to report to the apex
before the internal vortex draws the material up and out.
Clearly, some internal circulation of marginal particles
occur. The hydrocyclone sorts all this out in steady state.
BUT WAIT!!!! There is a similar looking hydrocyclone that
does a very different job! Works differently also! It is the
CWC or Compound Water Cyclone. It basicly has no upward internal core and it makes separations based upon specific
gravity, and of course, the bias of particle sizes. Did this
help you!
Sideliner
The hydrocyclone is vastly overated.
Take the flow formulas from any chart
for a fluted nozzle. The head loss is
that adapted for a fluted nozzle resembling
the inlet of the hydrocyclone. The curvature
is a minor factor, ingnore it. Just use the estimate for
a straight one. Now, as for the velocity. Is
is a simple (Q/A)=V where Q is flow in gpm,cu.ft./min,liters/min or whatever, A is the area
in the corresponding units. Generally, the external
votex velocity is the inlet velocity at the tangential point of entry into the hydrocyclone. (V*V)/r= acceleration or G's as they call it.
You can add head losses for the vortex finder and apex
if you are trying to extimate the pressure requirements
of the hydrocyclone. The manufacturers employ more sophisticated calculations but this will get you into the
ballpark. Sideliner
