Tesla turbine

8thAsia-Pacific International Symposium on Combustion and Energy Utilization
October 10-12, 2006, Sochi, Russian Federation
ISBN 5-89238-086-6
The Tesla Turbine Revisited
1,2
H. S. Couto1, J.B.F. Duarte2 and D. Bastos-Netto 3, 1
Department of Mechanical Engineering, UNIFOR - University of Fortaleza
Fortaleza, Ceará, Brazil
3
Combustion and Propulsion Laboratory, INPE – National Instituteof Space Research
Cachoeira Paulista, São Paulo, Brazil
3
E-Mail : demetrio@lcp.inpe.br
ABSTRACT
This work reviews the physical principles behind the Tesla bladeless turbine, a device invented by the brilliant
Croatian engineer Nikola Tesla. Following a quick discussion on the relative motion of rotating surfaces, it sets
up the transport equations describing the flow between parallelrotating disks, estimating the boundary layer
thickness under laminar and turbulent regimes, leading to expressions yielding the width between consecutive
disks. Once the working fluid is defined and its entrance conditions are established, then, if the needed (expected)
output power is chosen, this work shows how to calculate the total number of disks required to attain the desired
performance.Finally, it is also described the device behavior acting as an air compressor or water pump. These
authors are not aware of a comprehensive discussion of the fluid mechanics involved in the design of those
devices having been ever done. Besides the usual applications of rotating machinery, Tesla machines are properly
fitted when compact unities are required such as in the cases of isolated areasfor electric power generation. It
should also be noticed that, as a unique source of rotating motion, they can run under a very wide spectrum of
fuels and fluids in general.
Keywords: Tesla turbine, boundary layer turbine, rotating machinery
1.0 INTRODUCTION
Nikola Tesla broad field of interest led him to work in nearly every area of technical knowledge, ranging from his
well known andvaluable contributions in electrical engineering to his interest in developing a flying machine.
Indeed he was one of the pillars of scientific endeavors on early twentieth century. In 1910 he was awarded a
dual patent (British Office Number 24001) for a turbine and compressor using rotating disks as moving devices.
These machines using the same principles, operated in a similar manner. Theyconsisted of an array of parallel
thin disks very close to each other, kept apart by spacers (washers) and assembled (mounted) on a shaft, forming
a rotor which was fitted in a cylindrical housing (stator) its ends closed by plates properly fitted with bearings to
hold the rotor shaft. In the central region of the disks, close to the shaft, exhaust ports were opened, with gaps in
the spacers, thusproviding an exit to the atmosphere (or to a condenser, depending on its intended use, i.e., if a
gas turbine or a steam turbine, part of an otherwise standard thermal engine). A nozzle was located tangentially to
the bore of the casing, feeding the working fluid (be it steam or combustion gases), onto the disks, rotating them
while proceeding to the exhaust ports.
Since then several of theseunities were built [1-3], although none of them of the gas turbine kind, possibly due to
the lack of design data. Actually, as time passed by, no more disk turbines were manufactured and interest in the
principle lapsed [4].
Further these authors are not aware of a comprehensive discussion of the fluid mechanics involved in the design
of those devices. Hence this work, which following theestimates of the laminar and turbulent boundary layers
between rotating disks, suggests how to calculate the total number of disks needed for a desired performance to
be achieved. It also describes the device behavior as an air compressor or water pump.
1
Corresponding author
2.0 OPERATION PRINCIPLES
The fluid adherence to a wall (i.e., the “no-slip” condition) is the basic phenomenon behind...