[Fwd: [free_energy] Tesla Efficiency]
In Tesla's time, the efficiency of conventional turbines was low
because the aerodynamic theory to proper blade design et al didn't
exist and the engineering materials of the time put severe limitations
on operating speeds and temperatures. The efficiency of a conventional
turbine is related to the difference in temperature between the intake
and the exhaust. This requires that the materials used to construct it
be able to withstand very high temperatures for reasonable effiency.
Tesla's design sidestepped the key drawbacks of the bladed turbine,
but does suffer from other problems such as shear losses and flow
restrictions. Tesla turbine's advantages lie in the relatively low
flow rate and small applications. Maximum efficiency comes in this
system when the inter-disk spacing approximates the thickness of the
boundary layer, and since boundary layer thickness is dependent on
viscosity and pressure, the claim that a single design can be used
efficiently for a variety of fuels and fluids is incorrect.
A Telsa turbine differs from a conventional turbine only in mechanism
used to transfer energy to the blades. Various analyses show that the
flow rate between the disks must be kept relatively low to maintain
efficiency. This translates to needing to grow the number of disks as
the flow rate increases. In addition, the disks need to be as thin as
possible at the edges so as not to introduce turbulence as the fluid
leaves the disks.
Interestingly, the efficiency of the Telsa turbine goes down with
increased load. (Under light load, the spiral taken by the fluid
moving from the intake to the exhaust is a tight spiral, undergoing
many rotations. Under load, the number of rotations drops and the
spiral becomes progressively shorter. This increases the shear losses
and reduces the efficiency).
A claim of 95% rotor efficiency (as opposed to overall device
efficiency) for this design was published in 1991 by Professor Warren
Rice. Rice conducted a bulk-parameter analysis of model laminar flow
in multiple disk turbines. This analysis ignored inlet and outlet
losses.  (http://www.tfcbooks.com/teslafaq/q&a_033.htm) Tesla
claimed 98% overall efficiency. In the 1950s, Rice attempted to
re-create Tesla's experiments. Rice did not perform his tests on a
pump built strictly in line with the Tesla's patented design.
Rice's experimental system was a single stage version of the Tesla
turbine. It also used air as the working fluid. Rice's system was not
a Tesla multiple staged turbine nor did it possess Tesla's nozzle
design. Rice's test turbines, as published in his papers, produced a
overall measured efficiency of 36% to 41% (modern multiple stage
bladed turbines typically reach 60% - 70% efficiency). 
(http://my.execpc.com/~teba/debunk/lancaster.html) Rice suggests a
maximum fluid power efficiency of approximately 65% for boundary layer
turbines may be likely.
Update: Professor Rice's final work, published just prior to his
retirement in the early 1990's, is entitled: "Tesla Turbomachinery."
In this 1991 paper Prof. Rice states: "With proper use of the
analytical results, the rotor efficiency using laminar flow can be
very high, even above 95%.".
The Tesla turbine does not use friction in the conventional sense; it
precisely avoids it, and uses adhesion and viscosity instead. It
utilizes the boundary layer effect on the disc blades. This is an
important point of this invention.
* Rice, Warren, "Tesla Turbomachinery". Conference Proceedings of
the IV International Tesla Symposium, September 22-25, 1991. Serbian
Academy of Sciences and Arts, Belgrade, Yugoslavia.
* Tesla, Nikola, "Dr. Tesla Talks Of Gas Turbines". Motor World.
September 18, 1911.
* "The Tesla's steam Turbine". Scientific America, New York.
September 30, 1911.
External links and references
* US1061206 Turbine (http://phoenixnavigation.com/ptbc/tesla1.htm)
- New and useful Improvements in Rotary Engines and Turbines
* US1329559 Valvular Conduit
(http://www.tfcbooks.com/patents/valvular.htm) - Includes the Tesla
* GB186082 Improvements in the Construction of Steam and Gas
Turbines (http://my.execpc.com/~teba/debunk/Patent1.html) - Form of rotor
* GB186083 Economic Transformation of the Energy of Steam by
Turbines (http://www.execpc.com/~teba/debunk/Patent2.html) - Tesla
To drop of the list, send email to: