75mm Locky Kazoo (say that 10 times fast)

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Graham C. Williams
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Post by Graham C. Williams » Thu Feb 05, 2004 3:59 pm

Mike Everman wrote:It is fun. "the quest for the squashed dimension with identical flow rate to it's former diameter".
Dear Mike.
That just about sums it up. Take some time to look at simpler explanations of the Tesla Turbine if you can.
My first set of assumptions go something like - Not only does the perimeter of the tube remain constant but the boundary layer thickness also remains constant over the transformation.
Later I plan to allow for increasing viscosity and adhesion effects, as the plates get closer together.
I'll try to finish the first stage over the weekend.
Best Regards
Graham.
P.S. If any of you know something about these effects please feel free to chip in with any help you can offer.

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Post by Bruno Ogorelec » Thu Feb 05, 2004 4:58 pm

Graham C. Williams wrote:If any of you know something about these effects please feel free to chip in with any help you can offer.
Graham, since when has absence of knowledge been a deciding factor in the forum? If 'knowing something' were required, I would have stuck to travel business.

Interesting, that you mention the Tesla turbine in this context. It's very relevant point. The way I see it, in the Kazoo ports, the boundary layers are touching and/or overlapping. This is probably what you get in the Tesla turbine, too. Not what you want in you intake or exhaust.

If this is true, the transition -- as you broaden the gap -- will be sudden. At one point, the throughput will be pitiful and the next moment, half a milimeter later, it will increase steeply.

That would also mean that the radiused lip is not doing much. It probably needs a fair amount of flow to become effective.

By the way, why hasn't Nick posted anything in the forum? Rare is the combustion fan who doesn't have a soft spot for that other misbegotten hot air device -- the Tesla turbine. What is he using as a gas generator? what does the thing look like? How well does it work? Does he plan to add a Tesla compressor, too?

Mike Everman
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Post by Mike Everman » Thu Feb 05, 2004 8:33 pm

Thanks so much for the effort and interest. I think we're homing in on the quickest, dirtiest valveless known. The highest aspiration I can imagine would be someone someday confidently steering a newbie to the Locky Kazoo plans on the forum as a first engine! I can't wait to hammer on the thing this weekend!
Mike
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boundry layer

Post by Nick » Mon Feb 09, 2004 1:19 pm

WMJ Cairns has written an excellent book on Tesla Turbines of which i have a copy, he quotes a gap between plates of 0.025", he later gives dimensions of 0.5mm as the gap between plates in a model tubine he suggests building(not the one i built, as mine was adhoc).
maybe then a rule of thumb might be the boundry layer is most effective up to 0.25mm above the surface of the plate or tube wall?.

Nick

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Re: boundry layer

Post by Bruno Ogorelec » Mon Feb 09, 2004 1:29 pm

Nick wrote:maybe then a rule of thumb might be the boundry layer is most effective up to 0.25mm above the surface of the plate or tube wall?
Sounds awfully thin. Maybe the gradient is such that boundary effects are still noticeable well beyond that -- maybe up to 1 mm. I am deducing this from the fact that the increase in dimensions works wonders even for pulsejets bigger than Dynajet, which should already be moer or less immune to boundary layer conditions due to the size of its ducts.

Does the Tesla turbine book say anything about compressors? I've always thought a Tesla turbine pressurized by a Tesla compressor would be the way to go.

I loved your micro-turbine.

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tesla

Post by Nick » Mon Feb 09, 2004 2:02 pm

Hi Bruno,
i know 0.25mm is very thin and its true im sure that the boundry layers effect runs clear of that but 0.5mm is probably the optimum gap between discs given that if you have small gaps you can fit more discs in the same space, so yeah i would agree with you 1mm perhaps 1.5mm would clear you of appreciable effcts of the boundry layer Dependant on how smooth the surface was.
Yes the book has compressors in it, thats my next project, pretty much the same as the turbine except the blade chamber has to be on the form of a spiral volute, it took me a while to work out how to do that without cnc (thats coming but not here yet)but a reckon once i have the fixture ready it will be fairly straight forward.

Yes i like the idea of a tesla compressor powering a tesla turbine, Mr Cairns has afew designs of exactly that in his book. I also fancy making a tesla turbine compressor to power a simple bladed turbine to use the whole thing as a jet reaction engine, but time is as ever short and i have more pressing matters ref the bcvp to attend to.

Nick

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Post by Mike Everman » Thu Feb 12, 2004 7:53 am

Well, it looks like I'm ready for the first real try. Installed the fuel feed, exactly like mk's. It seems even more appropriate for Kazoo, since all incoming air must curl around the feed holes, being a skinny rectangular flow.
I'll probably try friday afternoon, after a three cocktail lunch! (not a regular thing';-)
Don't worry, I'll be prepared to omit the valve, and light with a hand torch, as my sparker is quite anemic. Wish me luck, I fear I squeezed this one too far, but gotta try anyway. Ooooh. I just noticed the photo is number 666! Bad. Very bad.
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Post by Bruno Ogorelec » Thu Feb 12, 2004 9:04 am

Looks swell, Mike. I am very much taken by your 'squeezed tube' approach. Hope it works. Eventually, this may become a good method of producing cheap and cheerful pulsejets. Maybe not by 2-dimensional flattening, but perhaps by putting 3 or 4 dimples in the sides. I am looking forward to your results.

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Hell-bent on forming

Post by Mark » Thu Feb 12, 2004 9:38 am

OK, what's next, the Kazoo jam jar by completely crimping shut the bottom of a pipe and snorkeling the top? Might be kind of fun to bang something out in record time from a simple tube.
You could throw in a spark plug and whatever else for effect.
With your Kazoo, it would be interesting to introduce liquid fuel from a round metal membrane diaphram in keeping with the Kazoo motif.
Mark

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Post by Mike Everman » Thu Feb 12, 2004 3:36 pm

Maybe not by 2-dimensional flattening, but perhaps by putting 3 or 4 dimples in the sides. I am looking forward to your results.
That's the goal, but the tooling still escapes me. The point currently is whether the increased surface area places an upper limit on performance, of course.
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Post by mk » Thu Feb 12, 2004 10:42 pm

Looks really good!

If the spark plug starting won't work, try some "blowing-the-flame-into-the-engine" by lighting propane at the intake and using a low air-speed source.

Good luck!
mk

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It runs!

Post by Mike Everman » Sat Feb 14, 2004 1:34 am

Check out the video! It runs and throttles beautifully, and even when the sparkplug shakes out!
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Post by Mike Everman » Sat Feb 14, 2004 1:40 am

Here's a longer run, changed exhaust extension 1" shorter to 6.5". First move of the extension. It throttles down to a purr about a third of the way in... I'm running out to run it again, with an extension that has some augmentation. Pictures tonight!
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Onward and upward

Post by Mark » Sat Feb 14, 2004 2:38 am

Congratulations on your molecular resonance!
Mark

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Post by resosys » Sat Feb 14, 2004 2:47 am

Nice work Mike!

It sounds good. Nice throttle response.

Chris

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