Could a Tesla Turbine Power a Wheel or Propeller for Propulsion?

[TheRyan]

I have read a bit about Tesla turbines and their amazingly high RPM output. I have also read that they don't product much torque, which is possibly why they haven't been used in anything more than dentist's drills and other things requiring speed but not high torque. How much power could one such as the turbine shown http://www.instructables.com/id/E5R0LEN6OFEP287CZL/?ALLSTEPS
output? Is it enough to drive a wheel or propeller for propulsion? Thanks!

 

[Astronuc]

The issue is low torque, high speed.

In propulsion, one needs to impart as much momentum to the propellant or working fluid as possible, and this implies substantial torque.

Then there is the matter of cavitation of the working fluid which puts a constraint on the max tip speed of the turbine/fan/compressor/propeller. Flutter or vibration of blades would also be an issue with respect to fatigue life.

Finally, the turbine/fan/compressor/propeller is sized according to some maximum stress or creep in the material, as well as thermodynamic efficiency.

 

[kach22i]

That is an interesting project page:
http://staff.washington.edu/sbtroy/turbine/turbine.html

There is this guy who built a large one for a ship of his. He decided to go with something even more exotic.

Homepage link:
http://www.seabirdadventure.com/

His original threads in BoatDesign.net:
1). http://www.boatdesign.net/forums/showthread.php?t=14276&highlight=tesla

2). http://www.boatdesign.net/forums/showthread.php?t=14277&highlight=tesla

 

[TheRyan]

Thanks for the links! That's pretty interesting talk about the nozzle size and shape. There seem to be many ways to "tweak" the turbine, such as changing the spacing of disks and nozzle geometry. It seems possible that a turbine such as this could be made to "shift" during use by changing the spacing between disks and opening/closing valves and re-shaping air passageways to change horsepower and torque.

 

[kach22i]

I'm sure if you want more information on that experiment "Seabird" will give it to you. He is a very open fellow, you might try contacting him though his site.

 

[niteshade]

I've been thinking about building a tesla turbine turbocharger, but I've been worried
that the exhaust side turbine would be warped by the high exhaust temperatures.
Is there a specific type of metal that would best resist this? I'm cutting the disks
from sheet metal.

 

[niteshade]

Also, if there are holes in both sides of the disks, one side
being exhaust, would the other side suck? (Not talking about the
inlet here, but the other side of the disk pack.

 

[Enthalpy]

The Tesla turbine is abandoned (except in some niches) because of its bad efficiency. Is relies on friction, which is a bad start.

With disks close enough, there is no fundamental reason for its torque to be worse than a good bladed turbine. The necessary disks spacings are nearly reasonable.

High temperature: this does require special alloys, yes. To resist corrosion, AND to avoid creep over time at high temperature.
In steam, X20Cr13 (=Aisi420) and its variations is already good.
Up to some +500°C, austenitic stainless works, but has a bad yield strength. NiCoMoTi25-15 improves.
Up to +650 or +700°C you have Ni- and Co- base alloys like Hastelloy, Nimonic families and the like, which do cost a bit.
Solutions exist over these temperatures but the alloys aren't available from the grocer's.

Design shall base on the creep strength over time at the operating temperature, which is much lower than the yield strength at room temperature. This is a further advantage of bladed turbines, where only the short blades are hot (often actively cooled), and the disk to hold them is cool.

 

[inspiredape]

Hi I am building an electric bicycle and I want to use a high rpm(6-8000 rpm) brushless motor. the gear reducers I've found have not been able to hande more than about 4000rpm. I was wondering if anyone has heard of using a tesla turbine as a sort of reduction/torque convertor. My idea is to make something that looks like a clutch with input and output disks stacked and sandwiched with low tolerance in some sort of viscous oil and use the surface cohesion to transfer torque. In my mind the molecules of oil would roll against each other and create a kind of planetary like reduction. Is that completely ridiculous?

 

[Heat-pump]

Hello, I am new to this forum. Just studied the nozzle tidbit on the seabird site. Don't quite understand how this improves horsepower of tesla turbine. If it does to what extent would that be?
As long ago as this design has been around I would think the laws of economics would have developed this if any practical output was achievable. No?