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Air circulation question [Image attatched]

  1. Feb 18, 2014 #1

    My name is Tom and I had a theoretical question about general air pressure and circulation. i have attached an image to diagram the system I am describing.

    In this closed system loop there is one part of a loop filled with water and the other part filled with air at a higher pressure. They are separated by a one way valve that lets the air flow into the water only.

    Will the air continually circulate around this system?


    Attached Files:

  2. jcsd
  3. Feb 18, 2014 #2
    Short answer - NO.

    Longer answer - pressure at the bottom of the column of water ( from the gas pressure + mgh of the water ) is higher than the gas pressure at the value. No gas will enter the liquid. Why would you think that filling one side with a fluid of higher density ( so bubbles of gas could float to the surface ), would add anything to just having both sides liquid or both sides gas.
  4. Feb 18, 2014 #3

    The plan is to float something in the water side which will collect the bubbles to increase its buoyancy.
  5. Feb 19, 2014 #4
    Well, that system will not be able to do that for you, as no bubbles will enter the water the way it is set up.
  6. Feb 19, 2014 #5


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    You will basically need an air pump to provide a pressure at the bottom of the water column that is greater than the hydrostatic pressure of the water. Whatever the "high pressure" in your diagram (as it is drawn), water will flow up that side tube until the two water levels are the same.
  7. Feb 19, 2014 #6
    Let me know if this does not make sense but, the thought for the valve was that it would only allow air to flow into the water tank and not let water flow the other way. I am assuming that devices like that exist. maybe something similar to a squeeze ketchup/Gatorade bottle.
  8. Feb 19, 2014 #7


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    However you achieve it, valves / squeezing etc., you need pump to produce a small excess pressure at the bottom of that column. Adding the same pressure to both sides will achieve nothing.
  9. Feb 19, 2014 #8
    Can anyone think of a way to Keep the air pockets circulating? I want to catch them at the bottom of the water tank, float an object, then release the capture air, let the object sink and repeat.
  10. Feb 19, 2014 #9


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    Which bit about "air pump" that I suggested earlier is difficult to understand? Lol
  11. Feb 19, 2014 #10

    All right, take it easy there boss. I want to use this concept to produce electrical energy through induced emf using faraday's law. I don't want to consume energy to make it happen. Maybe a mechanical air pump just to pressurize the whole system.
  12. Feb 19, 2014 #11


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    The point is that you won't get any energy out unless you put some (the same amount plus some) in. Basic rule of Physics / life / bank accounts. You will need to do work on the air to produce the bubbles which you could then play about with to produce electrical energy (if you are ingenious enough). You don't get owt for nowt, as they say in Yorkshire.
  13. Feb 19, 2014 #12
    The energy i plan on putting is pressure before closing the system. So hand pumping air in to build pressure. If the system is pressurized and there is a one way stopper between the water and air i feel like the air would keep circulating.
  14. Feb 19, 2014 #13


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    It would move once and then stop. You can't beat the system.
  15. Feb 19, 2014 #14
    Why would it stop the pressure in the system would always be a high pressure i think. There would be no loss in pressure in the system overall, once the bubbles pass the valve the pressure would increase pushing more bubbles through the valve and so on.
  16. Feb 19, 2014 #15


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