Temperature/Pressure relationship

[tabletop]

Hello,

Im trying to work out what the temperature increase of a vessel full of water at 90 degrees C (194F) at atmospheric pressure after it is compressed to 10bar(145PSI) ?

Can anyone point me to a simple chart or formula to show this relationship?

Thanks.

 

[wayuu1981]

Water at 90 C and atmospheric pressure would be as compressed liquid, and compressing a liquid won't increase its temperature (at least not significantly).

By other hand, whit a higher pressure you can reach higher temperatures at liquid phase, but you need to add some heat in order to increase temperature, instead of adding compression work.

Javier Guevara E.
Projects, Mechanical Engineer
TERMOGUAJIRA - GECELCA S.A. E.S.P.

 

[insult2injury]

For an ideal compression process, follow a line of constant entropy (isotrope).

I2I

 

[quark]

I second wayuu. If the pressure is increased with a hydraulic pump, you should discount temperature increase. Isentropic process is more suitable to gases (adiabatic compression)

 

[rmw]

If you conpress the air above the liquid it will heat just as the air in the cylinder of a diesel engine does. That said, that is the theory. The actual temperature increase and its transfer to the liquid would be negligable in my opinion because unlike the compression in an engine which occurs over fractions of a second, pumping this up will allow what ever heat is generated to dissapate through the vessel walls, etc, and yes, some will go into the liquid and will dissapate through the walls from there (unless this is an insulated vessel.

But you can calculate the increase in temperature using the gas laws and then with some complicated heat transfer equations calculate how much you expect to go into the liquid but my recommendation is don't bother.

But, no there is no chart that I have ever seen. You have way too many variables to put it into chart form-pumping rates, vessel material, ambient conditions, etc.

rmw

 

[wayuu1981]

rmv, remember that the vessel is "full of water" according to tabletop, so it won't be any gas to compress.

Javier Guevara E.
Projects, Mechanical Engineer
TERMOGUAJIRA - GECELCA S.A. E.S.P.

 

[rmw]

Good catch Javier. I went back and reread the OP and it does not account for a blanket of air over the liquid. That said, your first answer is most appropriate for the question of the OP.

rmw

 

[tabletop]

This has been helpful. After a little experimenting I can confirm that the difference in temp in insignificant (for my purpose). I thought it would have been more.
Thanks folks.