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Heating of liquid when pressure 1bar-->5000bars

  1. Aug 17, 2015 #1
    Hello!

    I have some troubles finding a way to estimate how much temperature of liquid would rise when it is suddenly adiabatically pressurized to thousands of bars. In normal conditions liduids such as water are considered to be incompressible, but certainly not in 5000 bars. Because water (or any other liquid) gets compressed, also some heat should be generated. But how to calculate it and what are the constants? I am just curious about the magnitude of temperature rise, is it more like +0,1K, +1K or +10K. Of course this depends strongly on liquid, but I am interested of any liquid just to get idea how to calculate magnitude of temperature rise.

    Best regards,

    -Paavo Palikka
     
  2. jcsd
  3. Aug 17, 2015 #2

    Nidum

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    (1) I once designed a one shot impact absorbing device for a large test rig .

    Basically a piston in cylinder device using hydraulic fluid . When activated pressure in cylinder went in a fraction of a second from not much to somewhere in region of 65 000 psi . That's about 4480 bar . Hardly got warm .

    (2) Hydraulic systems working at 10 000 psi (690 bar) are common and there are some systems working at very much higher pressures . Pumps generally get warm after a period of use but they don't normally get excessively hot . Most of the heating actually comes from the fluid passing through the valves and from bearing heating - not much comes from the actual pressurisation .
     
  4. Aug 17, 2015 #3
    Thank you for your answer Nidum!

    Even heat 1-->5000bar does does not get device warm, I would be interested how this could be calculated theoretically. I forgot to say that this is rather theoretical question,

    .Paavo palikka
     
  5. Aug 17, 2015 #4

    Bystander

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    A "generic" compressibility for water is 30 ppm/atm.. Help you any?
     
  6. Aug 18, 2015 #5
    Bystander: Not really, but thanks for trying to help.
     
  7. Aug 18, 2015 #6
    Bystander's answer should really help. You just use the first law of thermodynamics, with the work equal to pdV. To do this, you need to have the PVT equation for the material, and this is where Bystander's answer comes in. You also need to look up the general equation for the effect of pressure on the internal energy of a material.

    Chet
     
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