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usnistgov / REFPROP-wrappers

Wrappers around NIST REFPROP for languages such as Python, MATLAB, etc.
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Convergence issue for pure CO2 in the two phase state, when input is density & enthalpy #594

Closed SoerenTropy closed 6 months ago

SoerenTropy commented 6 months ago

Hi,

I am aware that the Matlab wrapper is legacy but maybe there is a fix to this.

When I use refpropm.m to ask for properties of pure CO2 giving density and enthalpy, and a two phase state is probable, the evaluation either gives false values or fails to converge. The same inquiries resolved just fine in GUI and Excel.

False Value Example

p = refpropm('P','D',128,'H',390000,'CO2')

Expected Answer:

p =

3.7905e+03

Actual Answer:

p =

3.0755e+03

Nonconverging Example

p = refpropm('P','D',131,'H',140000,'CO2')

Expected Answer:

p =

7.2503e+02

Actual Answer:

Error using refpropm [DHFL2 error 226] 2-phase iteration did not converge.

Versions

REFPROP Version: 10.0 Operating System and Version: Windows 10 Access Method: Matlab

ianhbell commented 6 months ago

First you need to switch to the new interface. Then you have (some) options.

SoerenTropy commented 6 months ago

Thanks, switching to the Python wrapper solved the problem for me.