tesla turbine _ bladeless disk turbine (site)

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Building a Tesla Turbine from hard drive platters

Please note that I am not a Physicist or a machinist (yet). I have been interested in Nikola

Tesla for some time, and I was looking for a project to gain some experience in the machine

shop. My job is to provide Lecture Demonstrations, so my goal was to produce a teaching

tool rather than an efficient engine.

For background material, Wikipedia has several good review articles about Nikola Tesla, the

Tesla Turbine, the Boundary Layer Effect, and Reynolds Number.

Disks

At first I tried using CDs because of their large surface areas, but they didn't hold up too

well under the milling machine. I also had a stack of platters from old and defective hard

drives, but I didn't know if the smaller diameter disks would work as well.

One problem I ran into is that some newer hard drives use ceramic disks instead of metal.

They're still coated with metal, but they're thinner and a couple platters shattered when I

tried to machine them:

My original plan for the center hole pattern had small holes (for threaded rods and washers

for spacers), as well as large holes (for air vents).

a Turbine / Bladeless Disk Turbine http://www.phys.washington.edu/users/sbtroy/Tesla_Turbine/Tesla_Tur...

7 18/07/2012 12:20



The second set of platters had radial arcs cut in them such that the inside edge of the radialcutout is close to the outside diameter of the spacers that I removed from the hard drive

assemblies.

The hard drive platters were stacked and clamped to a rotary table between two sheets of

scrap aluminium but the top disk (above picture) still took some extra damage. The rest of

the platters look much better though (see the complete rotor assembly below).

Spacers

I decided to be lazy and use the spacers that were between the platters in the original hard

drive assemblies rather than machine my own. This increased distance (roughly .05" insteadof .012") may lead to turblent flow rather than laminar flow but will be close enough for this

project.

Shaft

With the turbine platters and spacers complete, I turned a shaft from round stock. The inside

diameter of both the platters and spacers is .98" which is the diameter of the thick section in

the middle. I left the whole length at .98" until I knew the width of the chamber and the

inside diameter of the bearings. The wide part is 1.77" long which fits inside the 2" thick

acrylic chamber.


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Collars

The collars are essentially wider versions of the platter spacers. The inside diameter has to

fit on the shaft, but they can't be too tall so they block the ventilation holes in the disks.

Also, they can't be too wide or they will take up too much horizontal space inside the

chamber. I made each collar .3" which is enough space for a #10-32 set screw to hold them(and everything else) in place.

Bearings

The bearings and brass fittings were the only new parts in this project (everything else was

reused from scrap materials). These metric bearings were pulled from a box of old and used

bearings and I had to machine the shaft and side panels to fit them.

Rotor Assembly

There are eleven platters and ten spacers held together by the two collars. The hard drive

platters are hard to keep clean so I wore gloves when assembling the rotor. There should be

a fair amount of pressure between the two collars or the disks will rotate about the shaft

instead of with it.

Chamber

The main chamber is an acrylic block machined down to 4.75" x 4.75" x 2". The squareblock was mounted in a 4-jaw lathe chuck, drilled, and then bored out. The final cutout is

about .07" larger than the disks. The air inlet is taped for a 1/4" pipe thread and all of the

other holes are taped for 1/4-20 socket head cap screws.


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Side Panels

The side panels are .47" thick acrylic and have untaped .25" holes for alignment to the main

chamber. The center hole is .6" with a .280" deep counterbore for the bearing. The bearings

are metric so I used the 4-jaw chuck and boring bar again to try for a press fit into the side

panel. However, I made the counterbore a few thousandths too big which allows the bearing

to rotate in the side panel.

Many other Tesla Turbines that I've seen online have larger ventilation holes in the sides. I

was going to cut the same radial pattern from the disks in the side panels, but I decided that

wasn't necessary after a trial run with just the .6" hole.

Assembly


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The two brass fixtures are a 5/16 - 45 tube union (picture 5), and a 1/4 tube, 1/4 pipe hose

barb (picture 6).

Complete Turbine

CAD File


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me the original idea), my boss John Davis (for going on vacation and leaving me to my own

amusement), and Ron Musgrave and Mike Vinton in the Physics Department Instrument

Shop (for all their patience and expertise).

Please send any questions or comments to me at [email protected].

Go back to my home page.

Go to the Lecture Demonstration webpage.

This page was first uploaded on 25.May.2006 and last updated on 24.August.2010.


tesla turbine _ bladeless disk turbine (site)

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