Paul,

I often wondered why I like those disc impeller pumps so much.  Then it
dawned on me.  Tesla turbine.

Not happy with how my ideal TC engine was physically forming up I
decided
to give the Tesla turbine another look.  I spent a sleepless night
designing a true spin muffler that would be driven by the exhaust of the
rotary engine.  Size restrictions dictate a six inch diameter turbine
section and perhaps one for each rotor housing.  A common shaft is do
able and puts the bearings outside the case. Most of the components
should be made from Inconel or even titanium. Stainless 316 is good
enough for the testing.  Laser cut plates absolutely.  At least for the
13B the Tesla turbines exhaust could exit near the intermediate housing
and  feed a small T4 hybrid turbocharger.  Tesla turbines are tune-able
for the desired rpm output by removing or adding discs.

Most of Tesla turbines motors out there have been running on high
pressure air or steam simply because it is available but hot gases are
also possible depending on the ratio of inlet to outlet port size.
Turbine efficiencies are quote at from 40 to 95%.   The higher figure is
nonsense IMHO.  Centrifugal turbine are in their mid 50s at peak so I
suspect the lower quote is closer to ball park.  Axial turbines are a
bit better but either of these high rpms or large diameter turbine are a
logistic nightmare.  I have believe a T4 radial turbine is not going to
be able to recover much more than 30hp. at speeds low enough for a
traction drive to handle it. The mounting and connection considerations
are also daunting.  This started to add up to unacceptable weights.

I had orginally designed a spin muffler around a central pipe punched
with bypass exhaust holes and a  with the planned  turbine to be mounted
outside on the muffler case. Making the spin muffler literally spin
saves space perhaps development time.  It it saves me from having to use
a supercharger so much the better.

 I can see a few points that may increase the Tesla turbine efficiency.
New spacing methods to lower windage,  texturing the discs, and
eliminating skin drag loss on the outer end housings.  If nothing else
it would make a heck of  a quiet muffler.   Injecting air into the
exhaust nozzles would help contribute to a complete burn and increase
inlet pressure.

Putting the turbocharger on the outlet of the Tesla's spin muffler would
subject it  to lower temperatures.  Will it work?  Who knows but at
least this is something I can build and test.

Anybody else have some thoughts on design feel free to chirp in.
Depending how it mounted it could feed the power to the accessory side
or the PSRU side of the engine with the obvious differences in required
shaft lengths.

Now I am thinking to make a prototype with the housing made of a six
inch
ID Inconel pipe.  Discs will be SUS316L.  2.0 mm thick. Spacing at least
2.0 mm. Numerous discs. Both exhaust pipe rectangular  and tangentially
wrapping at least 60 degrees around the outer muffler housing.


Doug in Japan


That is interesting.  I have been thinking along the same lines
recently.  I'm building a 14" disc prototype.  I guess my input would be
to consider water injection as well.  I've seen posted the thought that
spacers on the periphery don't degrade efficiency.  If you used wafer
thin ferrite magnets you might be able to use the turbine as your
alternator.  I'd be very interested in seeing any formulae you may have
found in your research to calculate efficiencies, etc.
Decker, Michael