[Gasification] tesla turbine - debunked

[Ken Boak]

List,

Before we get all excited about Tesla turbines,  a quick search on Wikipedia 
will reveal the state of development of this device.

Often the efficiencies quoted are "rotor efficiencies"  which basically 
equates the losses in the rotor due to windage (drag) and the bearing 
losses.

It's like saying that a 100 hp car engine is 98% efficient, when only 2hp is 
lost into the bearings, piston ring friction and crankcase pumping losses.

Tesla gave up on the turbine, because it was extremely difficult to prevent 
the disks from warping in the constant heat.

The following is indicative of the confused state of affairs: from 
http://www.tfcbooks.com/teslafaq/q&a_033.htm


Ken


I've heard stories about the Tesla turbine that cite a figure of 95% 
efficiency, and have been unsuccessful in obtaining any information 
regarding this claim.  I was wondering if you could help in some way.  In 
addition, why haven't these devices been utilized in the mainstream.  Its 
hard to believe that it wouldn't have peeked its head out somewhere in the 
commercial realm.

I'm fairly certain the 95% figure you heard about can be traced back to a 
paper written by a Prof. Warren Rice, titled "Tesla Turbomachinery," and 
published in the Conference Proceedings of the IV International Tesla 
Symposium, September 22-25, 1991, Serbian Academy of Sciences and Arts, 
Belgrade, Yugoslavia.  Professor Rice states that bulk-parameter analysis 
has been used to accurately model laminar flow in multiple disk rotors, 
asserting that "...calculated results for laminar flows are in excellent 
agreement with experimental results for such flows. . . . With proper use of 
the analytical results, the rotor efficiency using laminar flow can be very 
high, even above 95%. . . ."  Keep in mind that while the rotor efficiencies 
can be very high, the fluid flow losses entering and exiting the rotor can 
be significant and difficult to reduce.  According to Prof. Rice, "There is 
little or no literature devoted to the flows that cause the main losses in 
Tesla-type turbomachinery."

As for why the disk-turbine design hasn't seen significant practical 
application, this is a complex issue.  According to the Tesla Engine 
Builders Association, mainstream application of the basic technology has 
already been achieved in the industrial pumping arena: "Texaco claimed in 
1986 they were saving $68,000 per year per pump."  Perhaps practical 
application of the gas turbine is being hampered because Tesla's stated 
claims for the engine have been difficult to reproduce in the real world. 
Sonny Entrican's efforts as recently reported in the TEBA NEWS are a prime 
example.  For a couple of years now he has been attempting to get a 
single-stage 48" gas-fired turbine to self sustain, without real success. 
(Self-sustained operation means that the power needed to propel the upstream 
screw compressor is provided by the turbine itself.)  While he appears to 
have developed a functioning gas turbine, Tesla himself had insurmountable 
difficulties when it came to the introduction of a commercially viable 
version.  By the way, Prof. Rice cites a "wide-spread belief" that the 
fundamental turbine design will see greater utilization in the future based 
upon its durability under adverse operating conditions.  Other factors 
leading in this direction are the inherent simplicity of the disk-type 
rotor, and recent advances in materials technology.