Originally published at: https://boingboing.net/2019/12/12/see-the-magic-of-a-tesla-valve.html
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Neat. Although in small doses it seems to do more to restrict the flow than cut it off. I wonder how many of those little chicanes would be necessary in a typical industrial application, like a household gas line?
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Think smaller… real small.
(Tesla Valve discussion at 09:18)
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Burning propane does not seem like a smart way to demonstrate this. Wouldn’t ignition generate new pressure within the valve itself? That’s not how it’s designed to work.
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I have not been able to watch the video all the way through yet, or with sound, but I imagine the geometry is quite persnickety to obtain 100% effectiveness
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But FIRE. Okay, fire isn’t flow, and so has no more connection to what’s actually going on than would a grapefruit or a performance of Fucik’s “Entry Of The Gladiators”, but FIRE!
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Very cool, but not a checkvalve, more of a flow restrictor. We typically don’t count on checkvalves in my buisness as absolutely stopping flow, but some are certainly better than others. We’ve counted on these guys’ products for some more critical applications. https://mokveld.com/en/axial-check-valve
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There appears to be a subtle difference between what is in the Tesla patent and the model in the video. Namely the shape of the “fins”. In the video model they’re nearly perfect tear-drop shape, whereas in the patent they appear to be asymmetrical with regard to the “in-board” side. The model in the video would seem to direct the stream around to perpendicular to the main flow channel, whereas the patent would seem to go a critical bit further towards forcing the flow toward the full reverse direction. Makes one wonder if the desired one-way-ness could be improved/optimized with a little more nuance to the reverse paths.
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What’s a Tesla Vilve?
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When using a combustion process I feel like he isn’t taking into account the vacuum created as the flame moves forward. Even in the forward flow configuration, an extremely long valve is going to impart a vacuum behind the flame front eventually slowing it.
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Yep. I think pumped-in dyed water would have done the trick. Or even just orienting the valve vertically then simply pouring in the dyed water to observe the difference in flow through.
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This invention was a critical component of Tesla’s proposed ray-gun weapon, which was essentially a particle accelerator with one open end. (This valve was necessary to maintain a vacuum)
Definitely an interesting idea, but I can’t say I’m terribly upset that he never received the development funds he sought for this one.
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I would like to see this in Schlieren vision!
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I believe he acknowledged that was a likely, unforeseen contributor and that such valves are typically not used in this way. He also implied he may try a larger experiment to see if this ‘discovered’ feature could be exploited and magnified to potentially supersonic speeds.
You’re right about there being better ways of illustrating - the video provided by Akimbo_NOT shows another, although one with it’s own limitations.
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Probably. But not nearly as much fun and wouldn’t go bang. Also, was so hoping this wasn’t about a new Elon Musk vehcle. Was happy
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That kind of Tesla valve would have been one of these bad boys:
https://5.imimg.com/data5/XE/LS/MY-4770623/zener-diode-500x500.jpg
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You can’t. It would break the laws of thermodynamics. Imagine you had such a geometry. Add a pipe connecting the two ends. Insert gas at initially uniform pressure throughout the system. From diffusion alone it starts moving through the valve. This creates a pressure increase at the exit of the valve, making gas flow back to the beginning through the pipe. Perpetual motion machine
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In the video model they’re nearly perfect tear-drop shape, whereas in the patent they appear to be asymmetrical with regard to the “in-board” side.
Hmmm… 
…this is from about the same era as some rapid advances in mathematical fluid dynamics (as well as early turbulence results). I wonder if there’s a calculation in there for 2D flow in a torus that he’s used. It’s not clear to me, completely, what Tesla’s intended flow regime was but I’m guessing high speed.
I’m also left wondering if there’s a 3D version that might work.
If Telsa is thinking about pushing flow supersonic through an expansion then reflecting it, maybe that might just do the trick, at least for that regime.
… this is going to bug me …
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You say that like it’s impossible 
/s
In seriousness however, thank you for the analysis, I hadn’t considered it. Today I learned something new!
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My first thought upon seeing the wood-and-glass model was that it wasn’t rotationally symmetrical about the axis of travel. I was envisioning a screw-shaped chamber. Hmm…
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