Rellative pressure/specific volume

[Patrick fox-roberts]

Can I get these out of coolprop for water anywhere - sorr if this is trivial but I can't find them anywhere

Pat

[Reiner Mayers]

Pat,

you need to be clear about what you mean with relative pressure.

Specific Volume is         1/density

Density you can get like this (Python):

# Import the PropsSI function
from CoolProp.CoolProp import PropsSI

# Density of liquid Water (Q=0) at 1 atm
PropsSI('D','P',101325,'Q',0,'Water')

# For pressures in Pa provide a Temperature with Quality, here 20°C, liquid

PropsSI('P','T',293.15,'Q',0,'Water')

Reiner

Am 04/18/2017 um 12:04 PM schrieb Patrick fox-roberts:

Can I get these out of coolprop for water anywhere - sorr if this is trivial but I can't find them anywhere

Pat

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[Ian Bell]

Thanks Reiner!

On Tue, Apr 18, 2017 at 4:17 AM, Reiner Mayers <reiner...@wirag.org> wrote:

Pat,

you need to be clear about what you mean with relative pressure.

Specific Volume is         1/density

Density you can get like this (Python):

# Import the PropsSI function
from CoolProp.CoolProp import PropsSI

# Density of liquid Water (Q=0) at 1 atm
PropsSI('D','P',101325,'Q',0,'Water')

# For pressures in Pa provide a Temperature with Quality, here 20°C, liquid

PropsSI('P','T',293.15,'Q',0,'Water')

Reiner

Am 04/18/2017 um 12:04 PM schrieb Patrick fox-roberts:

Can I get these out of coolprop for water anywhere - sorr if this is trivial but I can't find them anywhere

Pat

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[Patrick fox-roberts]

Reiner

thanks for reply

1st....I don't know why I said for water I am actually interested in air.

I am interested in relative pressure for isentropic processes i.e  Prel = exp(s0/R)  and relative specific vol   vr = T/Pr  where s0 is the integral ( Cp*1/T ) dT with a 0 reference temperature of 0 kelvin

Pat

[Patrick fox-roberts]

typed properly:

 function s⁰, standard-state entropy, is defined as

On Tuesday, April 18, 2017 at 11:04:29 AM UTC+1, Patrick fox-roberts wrote:

[Reiner Mayers]

Hi Pat,

Coolprop can deal with humid air, you will find the description of the model and examples here :
http://www.coolprop.org/fluid_properties/HumidAir.html, it is very similar to the water example I sent.

Afaik relative pressure is from Metereological science and the models do not deal with that. I suggest you
get the property data from Coolprop and calculate the integrations e.G. with scipy.integrate in Python,
Python Sage might be of help too. 

Reiner

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