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Crit. & Sat. Properties and hfc134a Errors #14

Closed GoogleCodeExporter closed 9 years ago

GoogleCodeExporter commented 9 years ago 
What steps will reproduce the problem?
1. Using critTemperature, critPressure, satTemperature,
setState_satVapor, or setState_satLiquid with water from liquidvapor.cti 
2. Plot vapor dome and heat pump cycle for hfc134a, results appear slanted
from correct answers

What is the expected output? What do you see instead?
1. Critical and saturation values should be returned, and sat. states
defined, however, errors are returned
2. Vapor dome and heat pump cycle plots that are generated don't match
published data

What version of the product are you using? On what operating system?
Cantera 1.7.1 through matlab on Windows 7.

Please provide any additional information below.
All critical and saturated functions work properly in Cantera 1.6.1.,
hfc134a issues appear in both versions.

Original issue reported on code.google.com by pdmob...@gmail.com on 19 Mar 2010 at 10:56

GoogleCodeExporter commented 9 years ago 
Issue 1 seems to have been fixed in Cantera 1.8 beta, but Issue 2 regarding 
hfc134a
is not resolved in the latest version of Cantera.  Attached is a sample 
regenerative
heat pump using hfc134a schematic and P-h and T-s diagrams.  The T-s diagram is
slanted from what it should be.

Original comment by pdmob...@gmail.com on 14 May 2010 at 12:39

Attachments:

GoogleCodeExporter commented 9 years ago 
What are the published data that Cantera appears to disagree with? Can you post 
a script using Cantera that shows the discrepancy?

Original comment by yarmond on 28 May 2011 at 12:55

GoogleCodeExporter commented 9 years ago 
Attached are P-h and T-s diagrams for hfc134a produced from cantera and the 
code used to produce them (the plotfixer program that is not attached just 
formats the graphs).  Also attached is a copy of a correct P-h diagram from 
Thermodynamics: An Engineering Approach by Cengel and Boles.  The main problems 
with the cantera diagrams are the negatively sloped isentropes on the P-h 
diagram (meaning enthalpy is decreasing when you put in isentropic work), which 
mostly occurs under the dome, but also above the dome for the 1 kJ/kg-K 
isentrope.  The T-s diagram also leans to the right (which they are not 
supposed to do) and has very positively sloped isenthalps (meaning entropy 
would be decreasing in an isenthalpic expansion through a J-T valve).  So it 
seems to me like there is something wrong with the way the vapor dome is being 
found.

Original comment by pdmob...@gmail.com on 1 Jul 2011 at 1:53

Attachments:

GoogleCodeExporter commented 9 years ago 
Attached is the correct P-h diagram from Cengel and Boles.

Original comment by pdmob...@gmail.com on 1 Jul 2011 at 5:29

Attachments:

GoogleCodeExporter commented 9 years ago

Original comment by yarmond on 15 Apr 2012 at 2:51

GoogleCodeExporter commented 9 years ago 
Tests that compare against reference values (from the NIST Chemistry Webbook) 
were introduced in r1440. This error has been corrected in r1441, and Cantera's 
results now agree with the reference values.

Original comment by yarmond on 7 May 2012 at 6:25