Some time ago somebody (forgotten who) mentioned, in passing, that hard drive discs might serve as rotors in a Tesla Turbine. I had been working for some time on that idea and now I am finally ready to show the world (or at least RCM) the results.
on Tesla Turbine - go figure :) The page is still incomplete but the basics are there.
Very clever! What fluid are you going to use to drive the turbine? Air, I hope. As I recall the usual magnetic coating is not water proof and the aluminum plates don't like moisture. I think newer drives use polished glass plates.
I love it when someone is able to put trash to a good use!
When you get ready to scale the turbine up a bit, I have several 10mb
14"-16" disks from an old DEC computer. I am not sure if I have any hubs or not.
Essentially it is just a model but..... The output end of the shaft is a duplicate of the shaft on my Dumore tool post grinder so those attachments can be used on the turbine. I am sure there are going to be many practical uses for it.
Chuckle. Performance and efficiency - two words that are seldom heard in my shop. I am sitting here watching hurricane force winds rip up the ocean in front of the house. Starting to pack up the shop for the winter. Gallons of LPS3 and all that. In a couple of weeks I am off to my 'alternate' home in Honduras so not much more will happen here until spring. At that time I will set about building the instrumentation I dreamed up over the winter.
Indeed! This definitely ranks as one of the niftier hacks I've seen. Can't wait to hear about power output and the rest of the details.
As a side note, this has inspired me to start looking at that scrap 3' chunk of 14"x8" "engineered wood" main beam from the house as a potential housing for a many-many-more disks on an even longer shaft version done in a wood case. If I've properly understood what I've read about TTs, it would seem to me that increasing disc count can do one thing, and one thing only: Increase output torque. (Yes, Virginia, I'm certain there's an upper limit of how much fluid you need to feed it to get it spun up)
I know, I know, I'm a heretic, working in wood... But hey! The material is there, and at this moment, it's considered something to be hauled to the dump! Chopping it up and making one of these gizmos out of it would only be enhancing its value! :)
Ken: Love the milled spiders - The spooky part is I keep glancing at the stack of them that's visible in the other window and seeing spiders for
45 RPM records :)
Suggestion for improvement if there's a "next version" in your shop: I've done some reading on these little beasties, and they, like so many other nifty gadgets that Ol' Nick came up with, intrigue me. One of the things I've learned from that reading is something that you mention on your page - one of the key things is putting the drive fluid to the rotor-bank at as close to a perfect tangent as possible, and *WITH AS LITTLE TURBULENCE AS POSSIBLE*. (Emphasis mine)
Now, your manifold bar/nozzle bar setup is an excellent idea, but I think I see a flaw in it that's quite likely to be putting extra turbulence in the fluid path, but could be tuned up pretty easily, with potentially significant improvement over the excellent-sounding (so far
- I'm waiting for the torque figures :) ) performance with what I think would be only a slight alteration of what you've already got.
It isn't clear for sure from your commentary what, if any, kind of plans you might have for maybe producing/selling this neat little widget (which doesn't even consider whether there's an exploitable market for it if you want to try), so do you want me to talk about the idea I've got "in public", or would you prefer to go to email or some other medium?
Let's keep it all in public - that's what this group is all about eh? I present the idea and my version in the hopes that someone will (and I just know they will) come up with something better. Your comment about 'as little turbulence as possible' is right on the money.
Hokay, then... Here we go! :) Looking at I see a 180 degree turn in the fluid path. Even if you point the brass fitting the other way, you're still going to be turning two 90s between the supply hookup and the nozzle opening. Replacing it with a straight fitting is still going to leave the 90 of going through the manifold bar and coming out into the gap formed by the nozzle bar. The distance traveled after that last 90 can't possibly be anywhere near enough for that much turbulence to "settle out" before hitting the rotors.
Proposed fix/improvement: Add another plate, suitably drilled and tapped to accept a (preferably straight) fitting - Place it on the left side of the case as it's shown in the image noted, then lift the manifold bar and the left piece of the nozzle bar, and finish milling the "slot" on the top of the nozzle bar all the way to the leftmost edge of the current case before reassembling it. The new plate for the left side should be drilled and tapped in the right position to give the drive fluid a straight flow from source to rotor-bank, which should give a serious decrease in turbulence compared to the two right-angle turns you've currently got.
I think that would likely be counterproductive - *ANYTHING* standing in the fluid path is going to build turbulence, including fins. (unless you manage to stumble onto the secret of getting true laminar flow over an object in a fluid stream - in which case, you can hire somebody to design a "perfect" nozzle for you, since you're already a rich man from what the military is paying you for your anti-turbulence design. :) )
The goal in this case is to keep turbulence to an absolute minimum in order to maximize the coupling of the fluid to the rotors, so fin (or anything else in the stream) generated turbulence is a Bad Thing.