Paul,

I found a few papers on the Tesla turbine done by reputable people. Two
are attached. I have come across Warren Rice's work before and think he
points out some realistic areas that need improvemnent in the turbine
design. He also notes that high efficiencies in the nineties can be
achieve in the disc area alone if the flow is kept laminar.  On the
other hand improper spacing just creates turbulence.  Most builders
space two wide and use unessaryily thick blades.

The inlet nozzle and outlet diffuser is in need of better design.  The
biggest challenge is not the heat or high rpms.  Tesla turbines only
absorb 1/3 of the heat that a radial turbine does.
That mean the temps will only drop about about eighty five degress across
the turbine rather than the commonly 250F that a radial turbine absorbs.
    Most of that heat goes into the outer housing which should be fairly
easy to cool.  The worst part however hit near the exhaust part of the
discs.

The bad part of the design is after the gases have spiraled around the
disc imparting friction on the boundary layer, and bringing disc
velocity up to the gas velocity, the exhaust gas has to do  abrupt right
angle turns into the central  turbulent spinning exhaust ports.  Sort of
what the exhaust has to do on a Renesis engine. To add insult to injury
the exhaust gases exit in a less than ideal way without the benefit of
diffusers to slow them down.

On the inlet side most builders just inject air of steam into a
antechamber and let it the turbulence sort it self out into the discs.
Obviously some discs are loaded more than others.  A wiser way would to
have a scroll and the ultimate way some vane guides to from the exhaust
nozzle to the discs.

All this have been sorted out on the common turbo charger but not in the
most elegant way.  The housing has huge mass and it needs it because of
the heat it absorbs and gets rid of.  The Borg Wangner design with the
vaned inlets tend to guide the gases first tangently (70 degrees) and
then the turbine guides them axially as they do work impinging on the
turbine blades.  Notice the how nice the outlet is flared.  Lots of
research in those babies.

As for the tesla turbine only a few individuals have even bothered to try
them on hot exhaust gases though that is exactly what Tesla had in mind.
    The metallurgy wasn't up to it then but it could be now.  All
indications are that narrow gaps and the low vicosity exhaust gases
would give the best turbine performance.

A few researchers in Mexico have attempted to add vanes between the discs
in the vicinity of the ports in an attempt to solve a  problem that
didn't exist. If anything they lowered the efficiency but reducing the
wetted turbine surface.  The gases don't need to be channeled inwards.

The nature of the Tesla turbine is it does work by trading velocity and
pressure over the inlet to outlet.  If I can figure out an air bearing
arrangement I would like to have the gases exit tangently into a hollow
shaft through small holes the width of the gap.  This would maintain the
swirl pattern and allow the gases to spiral on out the tube end through
a rotating diffuser and into a stationary scroll exhaust manifold.


It is interesting to note that in stationary turbines running on high
temp. steam one 18 inch unit was putting out several hundred horsepower.
Tesla planned to compound that turbine and use the lesser velocity and
steam pressure in another turbine with more discs and differing gaps.

Of course it goes without saying that any turbine is going to run a lot
more powerfully at 18 to 25K. feet.

Doug in Japan

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"That mean the temps will only drop about about eighty five degress across
the turbine rather than the commonly 250F that a radial turbine absorbs."

The entire turbo charge runs cherry red which is 1700. It matters little if the
exhaust is only 1615 F.  1700 - 85 = 1685 F

That thing is going to come apart big time and you don't want to be within 100
yards. Hear is the sound its going to make.

    EOOOOWWWWBANG!!!!  :)

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ops!!  1700 - 85 is 1615 and not 1685. I hope I am not the only person reading
this :)

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Sorry about the two identical messages. The NSA is a bit slow today and I sent
it again because I did not think it went out the first time. Merry Christmas NSA.

I was telling Robin about the Tesla turbine and she said: "The appeal of the
idea transcends the reality of the physics." I think that applies to a lot of
things like the electric water pump.

Paul Lamar



Paul,
When using Bole,s law don't you have to use absolute temp? And where can I see
diagrams of this Tesla turbine?
Dave James

I don't see what that has to do with these diagrams?

Paul Lamar


Paul

I don't see what those pictures have to do with a Tesla turbine.  Two
words.  Boundary layer.
Very traction drive like.  Heat  transfer efficiency to the metal discs
is terrible.  Same principle keeps a rocket engine from melting and to
some extent the rotary engine as well.  It is not the sled hammer
approach of a heavy housing and an impulse driven turbo-charger, which
by the way will melt if its duty cycle is exceeded much over the
horsepower needs of the compressor it was designed to power.

Other turbine design principles apply to the Tesla turbine which produces
94% of max hp at  half-max rpms. Max efficiency is at max rpms though.
All in all because of the manner the torque, diameter and required
running pressures,  a small Tesla turbine running on hot wimpy gas
pressures of the rotary will not be feasible.  This turbine favors
larger diameter, cooler high pressure gases.  Steam is the ideal liquid.

Doug in Japan

Let us know how you make out if you are still alive :)

Paul Lamar


"a small Tesla turbine running on hot wimpy gas
pressures of the rotary will not be feasible."


This means my conclusion is it is not suitable for TC an airplane.  20hrs
of reading and a little research.

Doug in Japan