----- Original Message -----

**Sent:** Sunday, March 09, 2003 3:56 PM

**Subject:** Tesla Turbine recalculation

This may be of interest to your group

I have recalculated some data pertaining to my
recent article re using a steam driven Tesla turbine in a modern railway concept
steam locomotive, at webpage:

For calculation purposes, a Tesla stack of 30-discs
were used, where the main inter-active surface areas would be between 2-ft
radius and 3-ft radius, with 0.25"-spacing between discs. The total effective
area would be 900-sq.ft and the active inter-disc
volume would be 2.4-cu-ft, with a hydraulic radius of 0.4898". The calculated
back-pressure for a steam density of 0.25-lb/cu-ft and an average swirl
velocity of 2500-ft/sec at 2.5-ft radius, was 114-psia.

The Mach 2 inlet pressure was 129.7-psia at 400-deg
F (from a boiler delivering 1000-psia at 1000-deg F). For a maximum avarage
relative velocity (between steam swirl and discs) at 2.5-ft radius of
1000-ft/sec, the Reynold's # worls out to (0.25 x 1000 x 0.4898/12)/(3.56E10-7).
This last figure is the dynamic steam viscosity at 400-deg F. The Reynolds #
works out to 2.866E10+7, which yields a friction drag coefficient of 0.002.

Calculating maximum power, based on 35,000-Hp
coming from the boiler, with average relative steam velocity at 1,000-ft/sec at
2.5-ft.

Drag= (1/2gravity) x(V-squared * density * area *
drag coeff)

=6987-lbf at 2.5-ft radius at 4800RPM. This
calculates to 15,880-Hp, or 45% of the horsepower energy in the steam
leaving the boiler. As the mass flowrate is reduced, the relative velocity
decreases and the drag factor increase by 25%, using flat-plate boundary
layer theory. This means that at a relative velocity of 500-ft/sec, the
Tesla discs would still deliver around 4900-Hp at 4800-RPM and still with little
change in efficiency.

I'm not into the metaphysics of the Tesla engine,
however, I'd find single pass efficiencies of around 28% to 32% to be more
acceptable.

Regards,

Harry