Error surface tension in CoolProp v5.1.0

[abahman]

Updating to CP v5.1.0, I got the following error:

ValueError: p is not a valid number : PropsSI("I","T",328.9778772,"Q",0.5,"R410A")

while CP v5.0.8 gives not error!

[jowr]

Is that a surprise? Please correct me if I am wrong, but I would not know how to calculate the surface tension of a mixture of gas and liquid.

[ibell]

There are correlations for the pseudo - pure though
On Apr 29, 2015 12:12 AM, "Jorrit Wronski" notifications@github.com wrote:

Is that a surprise? Please correct me if I am wrong, but I would not know
how to calculate the surface tension of a mixture of gas and liquid.

—
Reply to this email directly or view it on GitHub
#636 (comment).

[ibell]

This should be an error, but a different error than what you got.

If you want to get the surface tension directly, see #640, I'm fixing this.

[ibell]

Basically, 0 < Q < 1 is undefined behavior for pseudo-pure fluids since you don't know what is happening with the mole fractions of liquid and vapor in equilibrium.

[ibell]

You need to figure out how you want to handle it yourself.

[abahman]

Thank you. This was helpful.

[ibell]

Does that make sense to you?

[abahman]

Yes.
I thought the surface tension is a function of quality!