Here's a project that uses some of those dead hard drives you've got lying around.

In the Tesla Turbine, air, steam, oil, or any other fluid is injected at the edge of a series of smooth parallel disks. The fluid spirals inwards and is exhausted through ventilation ports near the center of the disks.

A regular blade turbine operates by transferring kinetic energy from the moving fluid to the turbine fan blades. In the Tesla Turbine, the kinetic energy transfer to the edges of the thin platters is very small. Instead, it uses the boundary layer effect, i.e. adhesion between the moving fluid and the rigid disk. This is the same effect that causes drag on airplanes.

To build a turbine like this, you need some dead hard drives, some stock material (aluminum, acrylic), a milling machine with a rotary table, and a lathe with a 4 jaw chuck.

Wikipedia has a good review article (http://en.wikipedia.org/wiki/Tesla_turbine), as well as articles about

Nikola Tesla http://en.wikipedia.org/wiki/Nikola_Tesla,
the boundary layer effect (http://en.wikipedia.org/wiki/Boundary_layer),
and Reynolds number (http://en.wikipedia.org/wiki/Reynolds_number)
(which determines if the fluid flow is laminar or turbulent).

I run my turbine on compressed air (40 psi), and it easily reaches speeds of 10-15,000 rpm. While the speed is high, the torque is low, and it can be stopped with your bare hand.

I have more details on my webpage (http://staff.washington.edu/sbtroy/turbine/turbine.html).

Step 1: Make Ventilation Holes in the Platters

Step 1 should probably be to disassemble some hard drives but I assume that if you read Make, you've already figured out how to un-Make a hard drive.

The easiest way to make vent holes in the hard drive platters is with a milling machine and a rotary table. Center and clamp a stack of several platters to the rotary table and then you can cut any radially symmetric pattern fairly easily. Just be sure that you use aluminium platters because ceramic platters will shatter when you drill into them.

I made two sets of platters; one with a radial array of holes, and one with radial arcs. The platter with radial arcs in the picture was on the top of the stack and took the most damage. The platters beneath it have very little tear-out and look much better.

Step 2: Make or Reuse Spacers

The ideal spacing between the platters depends on several variables including the fluid viscosity, velocity, and temperature. You could go through the calculations (http://en.wikipedia.org/wiki/Navier-Stokes_equations) and make a set of spacers, or be lazy and just reuse the spacers from the disassembled hard drives.

I was lazy and reused the spacers that were originally in between the platters. The advantage to this is that they'll have the same inside diameter as the platters. They're about .050" thick where the ideal spacing is closer to .012" but the increased distance doesn't make that big a difference in this case.

Step 3: Make the Shaft

This is just a piece of aluminum stock turned on a lathe. The center diameter is about .98" (which is the inside diameter of the platters) and about 1.77" long (so it will fit in a piece of 2" thick acrylic).

The thinner sections on each end are turned to fit the ball bearings I pulled from a box of scrap.

Step 4: Make Collars

The collars are made from more aluminum stock are wider versions of the platter spacers. The inside diameter is also .98" but they're about .3" thick to hold a #10-32 set screw.

Step 5: Rotor Assembly

Center the platters, spacers, and collars on the shaft and tighten the set screws to hold everything together. I used 11 platters, and 10 spacers. Try to line up all of the ventilation ports. If there isn't enough tension between the two collars, the platters can rotate around the shaft instead of with it.

Step 6: Make the Chamber

This is a 4.75" x 4.75" x 2" piece of acrylic that was bored out on a lathe using a 4 jaw chuck. The intake hole is taped for a 1/4" pipe fitting and all of the other holes are 1/4 - 20.

I used acrylic because it's what I had around and because it's going to be used for lecture demonstrations. You can use metal or even wood. However, if you plan to use steam instead of compressed air, wood might expand too much.

Step 7: Make the Side Panels (stators)

The side panels are 4.75" x 4.75" x 0.47" acrylic with untaped .25" holes to screw to the main chamber. The center hole is 0.6" and the counterbore is 0.28" deep.

The two 0.6" holes (one on each side) are the ONLY exhaust ports. The air spirals inwards across the face of the platters, through the ventilation ports, around the air spaces in the bearings (2nd picture), and finally out through these two holes.

However, more exhaust holes in the side panels might improve efficiency.

Step 8: Assemble Everything

Step 9: Complete Turbine and Movie

Please post (or email me) any questions or comments and I'll do my best to answer them.

Thanks for reading,
Will a 12 v cigarette car charger attached tyre inflator br able to run this ???
<p>With low rpm but yes.... probably.</p>
<p>how powerful your air compressor?</p>
<p>i cant understand what your pdf says.</p>
<p>Cant wate to try</p>
<p>cant </p>
<p>Is it possible that instead of using acrylic plastic entirely, that I could use the right sized clear PVC pipe to enclose the discs? Please do not respond to my email, is expired and cannot get on. Please respond by comment.</p>
<p>Hi there, I'm interested to know whether or not is it possible to substitute the platters with custom cut aluminum.</p><p>Oh, and can you please specify what kind of compressor do you use to power it in the video, including its pressure and type? Is the power generated by the air flow from the compressor varying in different pressure? </p><p>Also, do you know how to calculate the power by using the tachometer? </p>Sorry for asking too many questions, and thank you for posting this!
<p>do you know if it can work with a water exit hole?</p>
<p>It has an exhaust hole. Can it use water? Sure. Will it lose efficiency? Maybe. </p>
<p>Maybe instead of using water or air you can use another kind of gas or liquid that might produce more friction on the platters and create more torque. I really have no idea what... Just trying to think outside the box here....</p>
<p>Increasing pressure, disk spacing, temperature etc all change the reynolds number and therefore the flow. Matching this to the turbine is the difficulty of the design. You can technically make any fluid match the turbine in use but it requires changing these parameters. </p>
Would it be possible to, instead of having the exhausted air be released, have it be forced into another tube to re-use it? (I'm toying with the idea of using this as a drive for an airsoft minigun, with the exhaust air propelling the BBs)
<p>If the turbine is very efficient, the &quot;air&quot; that is being exhausted will have to be re-compressed. Conversely, if you used the turbine to compress air to drive the minigun, then you simply need a power source and strong arms. </p>
<p>Is it possible to add more torque by attaching a gear system, or by adding &quot;fins&quot; to the disks. I realize that it will lose a lot of speed, but will it gain torque?</p>
<p>Adding fins changes the flow and reynolds number. You want more torque increase disk number and diameter, given that all other factors are perfect. </p>
<p>How are the discs attached to the shaft? are they welded? </p>
<p>same doubt can someone reply to my mail chilumulapraneeth93@gmail.com</p>
<p>This design uses collars that utilize screws to hold the disk together with friction. Tesla's design uses a keyed shaft. Another method is to use something like a dove tail and collars. This method is very simple and cheap. </p>
<p>I just want to purchase one of them .</p>
<p>star washer actually helps the rotation buy guiding the air/water to the vent holes as the star extends above the vent holes. If you can see what difference that makes in the rpm.</p>
<p>I want one!!!</p>
Nice, though I stopped reading the comments when some one started the god bs thing. Can we keep reality and stupidity separate please?
a conventional rotary compressor runs more than 100k rpm to develop vacuum to sucks outside air continuously thus compressed it.if this device run at that speed can it become a compressor???
For those that don't like math but are still confused: notice that it is basically a closed system (rotationally) from the point of force (the air being blown in). The air circulates in the first platter set until the air pressure is too great and it escapes through the center holes of the platters (ignoring air escaping from the outside edges). This creates a pressure differential between the side of the hole being &quot;pushed&quot; on and the &quot;back side&quot; of the hole, inducing a spin. The pressure differential builds in the next platter layer and then moves out again, and again, and again until it escapes freely from the last platter set's center holes. <br>Because of energy loss from air escaping around the platters, friction from the bearings and other natural energy sinks, the inside platters exert more torque pressure than the outside ones (math stuffs go here for proof). <br>Good thing about this design is that you can use some &quot;simple&quot; thermodynamics to have a relatively low pressure, large area front condensed into a high pressure, small area front to get your air pressure from the wind for &quot;free&quot; (think of a properly tuned funnel) to drive an electrical generating motor thingy off of the axle with those new found magnetic thingies...
<strong>I'd like to ask the silly question here, but, where does the pressed air comes out?<br /> Maybe i missed something...<br /> <br /> Thanks for the tuto.<br /> <br /> .:FFH:.</strong><br />
You're not! <br>This IS a stupidly designed device. <br>the air actually escapes thru the shaft hole.
This is actually correctly designed, with the exhaust escaping through the shaft hole. <br><br>The Tesla turbine relies on the boundary layer effect and centrifugal force. The air gets forced to the center and out the shaft hole. An exhaust port on the side would ruin the design of the turbine.
no. CENTRIPETAL. not centrifugal. why does everybody think its centrifugal??
Centrifugal doesn't even exist!
Centrifugal does exist, it depends on your plane of reference. If your plane of reference is the object which has a centripetal force acting on it, there is a centrifugal force.
Nope! :) Centrifugal is merely inertia perceived as a new force.
It's all to do with plane of reference.<br>If you have a rotating plane of reference, you can have a centrifugal force. Look at the Wikipedia article for it.
Nope! :) Centrifugal is merely inertia perceived as a new force.
Make a good gearbox and put it to a generator which will charge the compressor ;)
Law of conservation of energy prevents this. Gear backlash, for example? Air speed being lost to exhaust?
great project! have you ever done any test on how much vacuum this thing can generate? im currently designing a turbine that would pump air and have the shaft spun with an electric motor, one of my constrains is the intake size so i need to suck in as much air as possible and preferably compressed it as well
if you ave more info about these turbines please let me know, bart.patrzalek@gmail.com
Hello! <br> <br>Can the efficiency be improved by widening the Inlet Port? instead of just focusing on the blades in the center (does that mean the other disks arent getting airflow or something?) wouldnt that mean that more friction (even with the same amount of air) = More Power/Speed/Torque? Also, I cant understand where the exhaust ports are. <br> <br>This is a great project! <br>But I cant do it. xD <br>(3rd world/ too young problems.)
my Question is how much torck does this have can u run a generator off of it?
Hey I wanted to ask u that If u hook it up with a generator how much would it generate and its voltage pleas help
If you were to attach a motor to the shaft of the turbine, would that turn it into a pump?
I wonder if you could do me a favor re your tesla turbine, I reached a quantum figure of 17 thou gap between blades (for compressd Air) for a more fluid-like force on the turbines to increase torque. is it possible for you to try this for me.any added expense will be paid by me,or if interested external micro adjustments for simplified cnc made from Corian-bench top and any threaded rod-(zero play acheived) by using human error factor.
Studying Tesla's Patent plans I see two things that are missing from recent constructs. These are items 26, Circular grooves and 27, Labyrinth packing.<br>Tesla must have included these for a purpose though he doesn't mention why.<br>The labyrinth looks like a seal. <br>I wonder are the grooves a sort of brake or governing mechanism, the fluid gets compressed in the grooves and thus slows the turbine down, perhaps?<br>I know it must be fun to see how fast the turbine can spin but the practical thing must be to turn that spin into power.<br>Any ideas on the grooves and labyrinth and why Tesla included them.
http://youtu.be/1n_sB1-JNAY<br> <br> Check out this Youtube link. I used some of your ideas, and some of my own to build my own Tesla turbine. Hit 30,000 + rpm and still going to add some more hard drive plates...ENJOY!!!
If you connected the input of this to a gravity-fed water supply, could you use it to generate small scale renewable energy: e.g. use it to recharge batteries via a simple (ish) circuit, or would the water be too viscous for this design to work properly?<br><br>Thanks
It sounds to me like your suggesting we build a hydroelectric dam but instead of letting the water cycle do our biding we would re-elevate the water? What your forgeting is that your going to have to pump the water back up to an elevated state once it has passed through the turbine. Its an efficiency nightmare lol.
Use it like a regular hydro dam system, then run the spent water into a drain (or plant bed) afterwards. I'm aware thermodynamics might have something to say about pumping the water back up again and trying to get more energy out of it.
if you added some exhaust port, in-line with the cutouts on the disc, efficiency would increase massively. The way it's working in this setup, is pretty much choking the output down to pitiful levels - easily one of the nicest-looking ones I've seen in a while though <br> <br>and the perpetual motion comments? LMAO!!
Remember that Lord Kelvin was LMAO about the idea of powered flight!<br><br>If perpetual in the sense of forever, well highly improbable.<br><br>As to coupled occilator's with irreversible flows it happens in biology. <br><br>Thermodynamics<br>While the 1st law seems on the sturdiest ground experimentally. <br>The 2nd law as applied to thermodynamics is about energy density. Objects at a particular temperature if unrestricted by activation energies move spontaneously from high to low, and from dense to less dense.<br><br>3rd law that you can never break even except at 0 Kelvin is the add on law that may be cracked and or found exceptions too. Zeroth Law is just common sense as the commutative law of addition. It sets T.<br><br>3rd law is valid when considering reversible flows, but if one looks at coupled occilator s using irreversible flows out of phase one can see immediately that this is not necessarily so. <br><br>As to Boltzman you can argue that with irreversible flows that the state is not exactly returned to the same probabilistic state as before, but the averages can be! Think about that! That fits right in with Poincare thinking which informed Boltzmans work. So there is times arrow locally and as we extend the domain we get back to symmetry. Something exhibited in the real world, in chaos theory, and many other physical phenomena. Geometrically we can think of fractals. <br><br>So while it is true that in a simple expression of reversible processes the 3rd law is true, that we can only break even at 0 K and also can never reach 0 K because of Zeroth. We can always couple irreversible flows, which from a probabilistic standpoint cannot return to original state, but from a physical energy standpoint can return to the same average energy.

About This Instructable




Bio: I have B.S. degrees in both Physics and Electrical Engineering. I do Lecture Demonstrations for the University of Washington Department of Physics. I don ... More »
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