Learning Forum

[iason.basiakos]

Hello everyone, 

I'd like to kindly ask this forum's help regarding the correct use of the NIST REFPROP database in multiphase modeling. In the section "Limitations of the NIST Real Gas Models" of the Fluent User's Guide, it is highlighted that a NIST material can be used in single-component multiphase flow. My questions are the following:

1) Does the above mean that a single-component phase transition (liquid to vapour) can be modeled using the NIST REFPROP?
2) If so, should I use a console command to let Fluent know I'll be using the liquid state of the fluid of interest, as I should in general, or given the phase transition, which includes both liquid and vapour the above is unnecessary?

3) Since a single material node will be created under the Materials tab, how do I know that materials for both phases are taken into account?

Thank you very much in advance

[Rob]

Single component tends to mean that multi-species is not allowed. So you will still need a set liquid & vapour properties: one for each phase. 

[iason.basiakos]

Thank you very much for the prompt reply. 

So if I get it correctly, I can use the database, but I still need to define two materials, one for the liquid and one for the vapour phase?

If so, as soon as I set a liquid state in the material from the NIST database using the console command: /define/user-defined/real-gas-models> set-state, the vapour state ceases to exist. Could you please elaborate on the procedure?

Thank you very much again

[Rob]

Would a real GAS model give sensible data for a liquid? In most cases you wouldn't need a compressible liquid.