Problem description

The switch from methane_pox_on_pt.cti to methane_pox_on_pt.yaml input apparently broke the Python example surf_pfr.py (see original issue report #877).

Edit: The example catalytic_combustion.py is affected by a closely related issue (see #873).

Steps to reproduce

A run of the Python example surf_pfr.py currently fails (see #877). Switching from YAML back to CTI input restores the old behavior. It can be easily verified that re-creating YAML using cti2yaml does not fix the issue. The same issue also arises if the original file is converted from XML (via ctml_writer and ctml2yaml).

Behavior

Time integration reduces CO levels to negative values until the density itself becomes negative and an error is raised (see #877), which appears to be either due to a faulty cti2yaml / ctml2yaml conversion of reaction parameters, or a faulty initialization of a cantera object from YAML. The context points at an issue with surface reactions.

System information

• Cantera version: latest development (2.5.0a4)
• OS: Ubuntu 18.04
• Python/MATLAB/other software versions: Python 3.6.9

Additional context

• Broken surf_pfr.py example #877 (superseded by this issue report)
• Broken catalytic_combustion.py example #873 (superseded by this issue report)

The behavior became apparent after 1866e35 which switched example input files to YAML.