Disabling Low-temperature Validation for Mechanisms, Possible?

[Mo Adib]

I converted a Chemkin mechanism to Cantera format (yaml file is attached) successfuly, but I face some issues with validation of PLOG reactions at 200 K when I was trying loading the mechanisn into the Solution object in Cantera. I copied one example of the error below.

I know that this issue has been discussed before in this forum. I found a couple of thread from back in 2014, but I was wondering if the developers has added new features to be able to toggle off validation functionality temparorily via python interface or including certain keywords in the yaml file.

 InputFileError thrown by PlogRate::validate:

Error on line 34445 of ./ITV.yaml: Invalid rate coefficient for reaction 'RFLUORENE <=> C2H2 + C9H6-C2H' at P = 10133, T = 200.0 | Line | | 34440 | ! PLOG / +1.3000e-02 +4.3600e+92 -2.3080e+01 +1.1707e+05 / !! A*0.5 | 34441 | ! PLOG / +1.3000e-01 +9.1000e+101 -2.5220e+01 +1.3033e+05 / !! A*0.5 | 34442 | ! PLOG / +1.0000e+00 +4.2600e+82 -1.9180e+01 +1.2534e+05 / !! A*0.5 | 34443 | ! PLOG / +1.0000e+01 +1.2000e+56 -1.1650e+01 +1.0675e+05 / !! A*0.5 | 34444 | ! Jin et al., J. Phys. Chem. Lett. 2021, 12, 33, 81098114 > 34445 > - equation: RFLUORENE <=> C9H6-C2H + C2H2 # Reaction 1754 ^ | 34446 | type: pressure-dependent-Arrhenius | 34447 | rate-constants: | 34448 | - {P: 0.01 atm, A: 9.99e+136, b: -34.28, Ea: 1.951e+05}

[Ingmar Schoegl]

There is no option to skip low temperature validation at the moment, but the lowest temperature was increased to 300K in the last Cantera release. The Cantera version in the converted YAML file is 3.0.0a3, which is an early alpha version and was before this tweak was adopted. I was able to import your YAML file without issues on the current development branch and would expect that it will work fine on the latest stable 3.0.1 release also. 

Beyond, there is still an open issue on GitHub (https://github.com/Cantera/cantera/issues/1405) but as of right now, there is no resolution to side-stepping a check that is designed to avoid crashes due to taking the log of a non-positive value (see detailed comment https://github.com/Cantera/cantera/issues/1405#issuecomment-1343565542). 

Hope this helps,

-is-