Water Correlation Between Temperature & Pressure
Water Correlation Between Temperature & Pressure
(OP)
Somebody asked me this, and I don't know where to go find the information. Maybe one of you could point me to a reference?...
Is there a correlation between temperature and pressure for water? I know it's basically incompressible, but not entirely. The person who asked me said he had heard it was 100 psi/ degree F (he was wanting confirmation of the formula).
The volume is fixed (it's a steel pressure vessel), the water is sub-cooled (starting around 550 degrees) with pressure around 2000 psig.
If this is something obvious, please feel free to berate me -- I just am failing open.
Thanks
Is there a correlation between temperature and pressure for water? I know it's basically incompressible, but not entirely. The person who asked me said he had heard it was 100 psi/ degree F (he was wanting confirmation of the formula).
The volume is fixed (it's a steel pressure vessel), the water is sub-cooled (starting around 550 degrees) with pressure around 2000 psig.
If this is something obvious, please feel free to berate me -- I just am failing open.
Thanks





RE: Water Correlation Between Temperature & Pressure
I seem to recall that its a lot more than 100 PSI/deg F (assuming the vessel 100% filled and temp rising) if you keep the volume 100% unchanged (no bulging or anything).
I dont have databook here, but find the expansion coef. for water and the compressibility for water and you should get the result fairly easy
Best Reagrds
Morten
RE: Water Correlation Between Temperature & Pressure
At 550 °F, the specific volume of the liquid is 0.0218 ft^3/lb. At 600 °F, the specific volume of the liquid is 0.0236 ft^3/lb. This is an increase in volume of 8.257% for a 50 °F temperature change. To compress the water by 8.257% (to keep constant volume) would require a pressure increase of (300,000 psi)*(8.257%) = ~25,000 psi. Dividing this by the 50 °F temperature change gives ~500 PSI/°F.
These are rough numbers. The compressibility of water will be nonlinear for large pressure changes. Container thermal expansion and compliance will tend to slightly lower the numbers. At lower temperatures (~100 °F), the numbers work out closer to ~100 psi/°F. Hydrocarbons in schedule 40 carbon steel pipe are ~70 psi/°F. The bottom line is, don't heat liquid full sealed containers unless they are rated for very high pressures.
RE: Water Correlation Between Temperature & Pressure
RE: Water Correlation Between Temperature & Pressure
Morten and butelja (among others) addressed the question. Most impressively, they seem to be giving about the same answer they gave last time.
Haf