[hrt12]

Hey,

I am a new user on OpenFoam. I would like to run a compressible, multiphase (molten metal and air) case with compressibleInterFoam. I use “perfectFluid” for the molten metal and I have a question about the specific gas constant R. The significance of this value has already been discussed in the thread http://www.cfd-online.com/Forums/ope...ion-state.html .
Why is the gas constant in the tutorials for water 3000? I don´t know whether the value was calculated or just selected.

Regards,
Niklas

[muth]

Dear Niklas
Its easy to run that case, but the gas constant value given in tutorial is not correct. So kindly check all the values before you run your case.

Regards
musthafa

[hiuluom]

Dear all,

I computed the fluid constant R with perfect fluid state for water material that it is difference tutorial compressibleInterFoam OF 2.2.2



But in tutorial R equal to 3000 J/(kg K).

Does any people explain me what R tutorial value is?

Thank you so much,
Thanh

[student666]

I computed the fluid constant R with perfect fluid state for water material that it is difference tutorial compressibleInterFoam OF 2.2.2

R = \frac{8314.32}{Mole Weight}=\frac{8314.32}{18}=461.9066667 J/(kg K)

But in tutorial R equal to 3000 J/(kg K).

compressibleInterFoam : biphasic, compressible, equation of state

I was looking for an explanation of R and I found your post. I think your calc is correct.
According to a previous post, I think that value 3000 is to give an incompressible behavour to liquid phase of specie; 461.9 should refer to compressibility factor for vapour phase of water ...just a trick...should it be?

[Nainah]

Hi there,
In the compressibleInterFoam solver, how can the value of air density be adjusted?

Thank you