Fix Modelica.Media.R134a.R134a_ph.setState_pTX (only applicable for one-phase) #3463
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
beutlich
added
bug
wischhusen
approved these changes
Mar 2, 2020
thorade
approved these changes
Mar 2, 2020
| @@ -1943,12 +1943,10 @@ The function cannot be inverted in a numerical way. Please use functions <a href | |||
| if liquid then | |||
| damping := 0.3; | |||
| //damping on the liquid side | |||
| d := R134aData.data.FDCRIT*Common.CubicSplineEval(localx, dl_coef[int, | |||
| 1:4])*1.02; | |||
| d := R134aData.data.FDCRIT*Common.CubicSplineEval(localx, dl_coef[int,1:4])*1.5; | |||
There was a problem hiding this comment.
So the main change really is using 1.5 instead of 1.02?
As long term solution, the Newton iteration should probably be bounded and have asserts in it for the slope.
Also, we should have two tests: a Modelica test comparing forward/backward consistency of the Newton iterations; and a python script comparing values against RefProp (from python, the most convenient way is to use CoolProp to call RefProp).
There was a problem hiding this comment.
So the main change really is using 1.5 instead of 1.02?
Yes, it is.
Increase density start value for Newton iteration
beutlich
force-pushed
the
fix-again-setState_pTX
branch
from
467c94e
to
d1e1e22
Compare
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
After #3317, this is another attempt to fix Modelica.Media.R134a.R134a_ph.setState_pTX.
The property tables, especially for setState_pTX, created by T3276.mo look as expected now, if the density start value for the Newton iteration is increased.
setState_phX() (ref props in parentheses)
(511.9)
(389639)
(1591.11)
(71455.2)
(1220.13)
(234687)
(1190.76)
(245776)
(1294.78)
(200000)
(969.916)
(235741)
setState_pTX() (ref props in parentheses)
(511.9)
(389639)
(1591.11)
(71455.2)
(1220.13)
(234687)
(1190.76)
(245776)
(1294.78)
(200000)
(969.916)
(235741)
I also added the test model to ModelicaTest.
Resolves #3276.