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Dr. Storms comments intrigue me . As we continue to test
various parabolic shaped segments in our designs for vacuum induction mixer
feeding of products into process streams there are certain shapes of 3450
rpm speed rotating members that produce extremely " tight"
vortexes in the clear plexiglas test tank. The vortex forms at the bottom of the
tank and extends up to the face of the rotating member. Observing the
vortex " hunt" around the rotating member, it randomly " strikes" the member..
NEVER at the center but at the discharge orifices on the periphery. This
event occurs at around 20 sec. intervals and is quite visible causing the
entire unit with submersible motor ( 2HP) to " jump" on its sliding mount.
Entrained air in the water is also sheared off the member. Beside the main
vertical vortex created, there are a host of free spinning " pups" released that
are visible (contain an air center) for a short duration that bounce off all
four walls in every direction horizontal to diagonal in orientation plus an
occasional glowing bubble ( may only be reflection on the bubble from the light
below the tank)
Examining some rotating members that have been in
service feeding 12-15 % hypo show classic cavitation pitting near the orifice at
the periphery of the member.
Of interest .. the plexiglas tank bottom ( 1/2 inch
thick) shows a slightly indented circle ( smooth, not pitted)of 2 inches
diameter and several mm deep which may mean some plexiglas material has been
removed by action of the vortex. We also reversed the motor rotation to run
counterclockwise ( as a northern hemisphere vortex). The vortex cone was much
wider in diameter. The clockwise rotation produces a much tighter vortex column
and appears to exceed the speed of the rotating member at times . This view from
beneath the glass tank also allows us to see the vortex strike the member.
This information may be of interest because the event is
easily replicated each test.
We hoped to have the 10,000 rpm test unit with
15 hp VFD drive ready by now but, vibration problems require dynamic balancing
of the components , plus the heat generated in the oil filled annulus is a
problem. We have also been advised the higher speed unit may produce some
uv and gamma radiation. Perhaps some of our learned Vortexians may comment
on magnetics or radiation we may encounter and/ or measure. Our test facilities
are not "laboratory grade" but a 3450 rpm unit is available for study by the
serious Vortexian.
Richard
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