use refprop by matlab calculate Q with negative valve

[yplakaka]

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Description

[Hello , I am using refprop by matlab to calculate some valves, I met some problems when I was trying to calculate mixed refrigerants vapor fraction ,It showed a negative valve. and I also tried use refprop via python, the same negative valve showed]

Steps to Reproduce

1. [T_1=373.15;%K]
2. [P_1=19936;%kPa]
3. [Q_1=refpropm('Q','T',378.15,'P',P_1,'R134a','R245FA',[0.38376, 0.61624]);]

Expected behavior: [It should be 0.424]

Actual behavior: [the result calculate was -998]

Versions

REFPROP Version: [REFPROP 10.0]
Operating System and Version: [windows 10]
Access Method: [matlab]

Additional Information

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[ianhbell]

If I remember correctly refpropm uses mass fractions? I recommend to only use molar fractions although mass fractions are technically supported, there are a few bugs that are related to the use of mass fractions.

[yplakaka]

I checked the refprop DLL documentation. The reason of negative valve is that refprop thinks it is a Subcooled liquid, but quality not defined (usually P > Pc) https://refprop-docs.readthedocs.io/en/latest/DLL/high_level.html

[ianhbell]

Can you please confirm whether your compositions are mass or molar? Have you enabled the saturation splines? You should; it helps sometimes, but not always.