simple turbine design 1

[alansimpson]

I wish to spin up a disk 100mm to 20,000+ RPM for a test rig. At the moment I can get around 16,000 rpm with a compressed air nozzle and simple turbine. Any advice on turbine/nozzle configuration in order to optimize design.

 

[MikeHalloran]

Two nozzles?



Mike Halloran
Pembroke Pines, FL, USA

 

[JStephen]

I seem to recall from way back when that woodworking routers will hit 20,000-30,000 rpm- would that work instead?

 

[JRLAKE]

I'm sure you thought of this but I'll throw it out there. Have you tried a supersonic nozzle (converging / diverging)?

 

[unclesyd]

Here is a source of the sonic nozzle as posted by JRLAKE.

http://www.foxvalve.com/frameset-venturi.html

 

[arto]

could you pull a vacuum to lower windage?
try these guys:

http://www.barbourstockwell.com/

 

[alansimpson]

Supersonic nozzle sounds interesting. Where would I find such a thing. No luck on Google and foxvalve not suitable. thanks

 

[JRLAKE]

Without a sonic nozzle you cannot exceed the choked flow velocity. You can pull a perfect vacuum and have infinite compressed air pressure and you will still not exceed Mach 1.

I don't know where to buy such a nozzle. I know small ones exist because we used them in wind tunnel testing. Maybe a laboratory equipment supply catalog?

 

[btrueblood]

I would encourage you to calculate the windage drag on the 10-cm disk, and from that determine the horsepower you will require. See the following link:

http://ntrs.nasa.gov/search.jsp?R=3...ll&Ntx=mode%20matchall&N=0&Ns=HarvestDate%7c1

As Jstephen suggested, an air-driven router may be a good item to purchase, and disassemble to learn something about how to make a high-speed turbine. Forget supersonic nozzles, or any nozzle for that matter; you want to harness the expansion of the air to produce torque at very high rpm: you will need to make an axial-flow turbine, or possibly a mixed (axial/radial) turbine.

A quick back-of-the-envelope calc. using the moment coefficients from the above paper suggests that you might get a 1/4-hp air or electric router to spin the disk to 20k rpm in air. Balancing the disk for that speed, and keeping everything intact may be a problem. Suggest you watch this test from a distance, and keep yourself and anything/body else out of the "plane of rotation". Better, do it like the pros (barbour stockwell) and put it in a pit or stack concrete blocks around it.

 

[UMDpru]

how about googling a "Tesla Turbine" or is that what you are trying to build?

 

[hydtools]

You might look at high speed hydraulic motor.

http://www.parker.com/OILDYNE/CAT/ENGLISH/07_09SERIESHYDRAULICGEARMOTORS.PDF

Ted