Pressure Drop through orifices in a rotating disk

[RedCoat999]

I have two volumes separated by a rotating disk spinning at ~8000 rpm with five 0.125" dia (0.200" long) holes in it. They are machined in the disc at a diameter of 1.2". I know how to calculate flow with a certain pressure drop through these orifices if they were static, but how do I account for the fact that they are spinning at 8000 rpm? Surely this would hinder the flow somewhat?
Thanks

 

[shahyar]

Just my thought.
If I want to solve this problem, I'll changet it to a "static problem" with this assumption: rotating disc can be assumed a static "strainer". you can assume mesh size of this "strainer" based on dia and the number of holes as well as rpm of disc.Actually 8000 is pretty big and I think such assumption is not very wrong.

 

[MikeHalloran]

I think a pseudo-static strainer solution can work if the fluid is a gas.

If the fluid is a liquid, things could get interesting.

E.g., absent rotation:
The upstream isobars are hemispheres, and
The upstream flows are radially in toward the apertures.
The downstream isobars are ... not hemisphers, and
The downstream flows are toroidal, outside of the hole centers bounded by the chamber walls and the stream exiting the apertures.

With rotation, all the flows are sheared, and the path length for a given unit volume could get quite large, depending on the extent to which the bulk fluid in the chambers rotates with the disk.

It should make a hell of a mixer.



Mike Halloran
Pembroke Pines, FL, USA

 

[BigInch]

I would imagine it would be just horizontal flow from the near or in the film layer being sheared off and then blown through the hole.

BigInch-born in the trenches.

http://virtualpipeline.spaces.msn.com

 

[hydromech]

What if the shear value is high enough to allow the disc to create drag against the contact area with the fluid?

Could the a vortex be created in the area local to the disc and then for the fluid to flow axially though the disc whilst rotating at the same speed as the disc?

Conversely...what if the shear is very low and the liquid local to the disc becomes very turbulent, effectively blocking any flow?

I can imagine either one happening...

What about centrifugal forces, could the liquid properties be effected?

Hydromech

 

[RedCoat999]

BTW, the fluid is jet fuel.

 

[BigInch]

What kind of a machine do you call this thing?

BigInch-born in the trenches.

http://virtualpipeline.spaces.msn.com