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Units and values for Thermal diffusivity in MOLAR BASE SI do not seem to match #681

Closed PieterCornelisse closed 2 weeks ago

PieterCornelisse commented 2 weeks ago

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Description

In the MOLAR BASE SI units system the Thermal diffusivity should be in m2/s.

However they seem to be factor 100 too high when I am using the python wrapper.

I am looking at CO2 as pure fluid, and running along saturation line.

When I use the desktop application GUI I get: 295.86 K 6.1 MPa 0.00021727 cm2/s for Liquid 0.00031285 cm2/s for Vapor

At the same condition in the python wrapper working in MOLAR BASE SI units system I get value that is 100 times smaller reported as m^2/s. 2.1727e-6 m2/s for Liquid 3.1285e-6 m2/s for Vapor

But it should have been 10000 times smaller. So 2.1727e-8 m2/s for Liquid 3.1285e-8 m2/s for Vapor

Steps to Reproduce

  1. Define CO2 as your working fluid
  2. run for liquid and vapor: 
    RP.REFPROPdll("","PQ","TD",MOLAR_BASE_SI,0,0,6.1e6,0,[1.0])
RP.REFPROPdll("","PQ","TD",MOLAR_BASE_SI,0,0,6.1e6,1,[1.0])
  3. Check values and you will see that units are reported as m^2/s but value is 100 times too large.

Expected behavior:

Assumes values in order e-8 m2/s would come out

Actual behavior:

But values came out order e-6 m2/s, which is 100 times too large I think.

Versions

REFPROP Version: 10.0 Operating System and Version: Windows 11, via jupyter notebook
Access Method: Python wrapper

Additional Information

If possible, please post examples and/or screenshots of the issue.

ianhbell commented 2 weeks ago

See #646