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-   -   Thermophysical properties of steam? (https://www.cfd-online.com/Forums/openfoam-solving/134213-thermophysical-properties-steam.html)

massive_turbulence April 25, 2014 23:49

Thermophysical properties of steam?
 
Hello,

I'm just hoping someone could give me a shortcut to their thermophysical file for steam (or something like it). I haven't done this for anything yet so as a beginner it would be really nice to get a 'correct' file to use instead of spending hours going no where. If not that's fine.

thanks,

Andrew

adarsh tiwari April 26, 2014 00:56

Hi Andrew,

By knowing some properties you can easily do it, the simplest way is to simply modify the respestive case file from one of the tutorials and change some properties accordingly.

Steam is nothing but the gasified water depending upon the temperature and pressure, hence based on this the following links may help.
http://webbook.nist.gov/chemistry/fluid/

http://www.ohio.edu/mechanical/therm...ty_tables/H2O/

https://www.google.co.in/url?sa=t&rc...65397613,d.bmk


Best regards,
adarsh tiwari

massive_turbulence April 26, 2014 02:59

Quote:

Originally Posted by adarsh tiwari (Post 488287)
Hi Andrew,

By knowing some properties you can easily do it, the simplest way is to simply modify the respestive case file from one of the tutorials and change some properties accordingly.

Steam is nothing but the gasified water depending upon the temperature and pressure, hence based on this the following links may help.
http://webbook.nist.gov/chemistry/fluid/

http://www.ohio.edu/mechanical/therm...ty_tables/H2O/

https://www.google.co.in/url?sa=t&rc...65397613,d.bmk


Best regards,
adarsh tiwari

Thanks Adarsh,

I got this for air at this page http://www.openfoam.org/docs/user/th...37-2060007.1.1


Code:

air
{
    specie
    {
        nMoles          1;
        molWeight      28.96;                                                                                                                                                       
    }
    thermodynamics
    {
        Cp              1004.5;
        Hf              2.544e+06;
    }
    transport
    {
        mu              1.8e-05;
        Pr              0.7;
    }
}

and I'm not sure what

mu 1.8e-05;

and

Pr 0.7;

mean?

I'm also trying to double check their specific enthalpy for air to make sure it correlates with specific heat capacity, that way I can be sure that H is in J/kg.


Andrew

adarsh tiwari April 26, 2014 09:47

mu is viscosity, Pr is Prandtl number.

Well, I suggest you to read user manual for understanding each term ;)

massive_turbulence April 26, 2014 15:40

Quote:

Originally Posted by adarsh tiwari (Post 488373)
mu is viscosity, Pr is Prandtl number.

Well, I suggest you to read user manual for understanding each term ;)

I'm not sure where to find this in the manual

pRef 100000;


it's within the thermoPhysicalproperties for the hotRoom tutorial written above the mixture.

About the transport though, should I use a model called the sutherlandTransport if I end up changing the temperature of the grid over time. I assume constTransport is for a steady state system with no temperature change.

There's also the polynomialTransport but I'm not sure how to get that for steam. I would need it for temperatures between 373-1000 K just to be sure it fits.


thanks so far,

Andrew


EDIT
I think that according to this table http://www.engineeringtoolbox.com/wa...ies-d_162.html

the viscosity and Prandtl number for steam goes to zero which obviously makes sense.


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