Would this large scale "bubble pump" actually work?

Question

I have read about bubble pumps which work by heating water causing a phase change, the water passes through a one way valve and condenses thus pumping water.

Would this work at a larger scale as in my diagram below, or would the nature of the phase change mean that the pump would cavitate rather than provide suction?

@jsotola I have a small farm and we use solar piston pumps to great effect, this was just a thought experiment on reducing the number of moving parts — Jan Martin, Feb 15 '23 at 23:24
Use the condensation to drive a piston. Then you can do what ever you want to with the mechanical energy. — Phil Sweet, Feb 16 '23 at 04:10

score 0 · Answer 1 · answered Feb 17 '23 at 02:16

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Your pump idea needs to have a pulsing action. Heat the water up, generate a steam bubble, push water through the outlet valve. Then turn the heater off, allow the steam to cool and condense, suck water in through the inlet valve. Repeat.

This will work at quite a large scale, and I have made a couple of these in the past.

Note: At anything larger than a mm in size, you need to have the outlet valve BELOW the heater, otherwise the steam will go out the outlet valve, and not the water.

As for cavitation, this will depend on what temp you cool the water down to. The cooler the water, the more vacuum it can sustain without cavitation. Room temperature will get you to about 9.8 metres of head.

answered Feb 17 '23 at 02:16

PatMc

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Wouldn't the pulsing happen automatically, as the steam bubble leaves through the outlet valve, cold water would enter through the inlet valve dropping the temperature? Very interesting to hear you have done this before, do you have anything more you can share on this? I am now tempted to throw a few $ at an experiment... – Jan Martin Feb 17 '23 at 04:03
That's what I was saying about it depending on how large it is. For anything more than a mm or two, it would just end up bubbling like an electric kettle, no large single bubble of steam that produces a pulsing action. At the VERY small scale (where I've worked professionally) it's definitely done with a pulsing electric power. Pulsing very quickly, up to many thousands of times per second. There may be a size that works with continuous power. The advantage of the system is that experimenting like this is very easy once you've put together a basic prototype. – PatMc Feb 21 '23 at 23:14

Would this large scale "bubble pump" actually work?

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