C.5. Diagnostic Messages in the KINetics-log.txt File

The KINetics-log.txt file is a “catch-all” for many diagnostic messages that are generated by the CHEMKIN-CFD module. The most common types of messages are error messages related to setup or cell convergence.

Cell-convergence error messages can take a variety of forms. The most common are summarized in Table 5: Other Error Messages in KINetics-log.txt. In general, if there are just a few failed cells at the beginning of a simulation it is safe to ignore them. When the number of failed cells continues to grow with each iteration, there is likely an issue with the problem set-up or with the chemistry data. Table 5: Other Error Messages in KINetics-log.txt contains some broad suggestions of ways to improve cell-convergence behavior based on the type of cell failure message received.

Table 5: Other Error Messages in KINetics-log.txt

Error Message	Recommended Action
`FAILURE INITIALIZING SETTINGS FOR THE KINetics STEADY-STATE GAS-PHASE CHEMISTRY SOLVER`	Most likely suggests an error in setting the convergence criteria (that is absolute and relative tolerance) and the pseudo-steady-state time stepping parameters. Check that the user-provided values are reasonable.
`WARNING: Exceeded allowed time-stepping intervals in cell`	Indicates that a convergence problem was encountered during steady-state solution, where time-stepping is used to help advance the steady-state iterations. In this case, you can either ignore the message (see if the cell convergence recovers in subsequent iterations) or try to increase either the time interval or the number of allowed time-stepping intervals (See Table 2: Summary of Advanced CHEMKIN-CFD Parameters for more information).
`KINETICS ERROR: SOLUTION FAILED`	Indicates that the cell failed to converge (either steady-state or transient).In this case, you can either ignore the message (see if the cell convergence recovers in subsequent iterations) or try to modify some of the user-controlled parameters to improve convergence (See Table 2: Summary of Advanced CHEMKIN-CFD Parameters for more information).
`Warning - The transient chemistry solver tried 500 steps without convergence in this cell; 500 more steps will be allowed`	Indicates that the problem is difficult to converge so that the transient solver is taking extra steps. However, it is only a warning and the cell has not actually failed. If you receive an excessive number of these messages, try reducing the absolute or relative solution tolerances that control the CHEMKIN-CFD solver.
`KINETICS ERROR: Problem getting species names; Check that the CHEMKIN files have been processed correctly`	Indicates a possible error in the pre-processing of the gas-phase chemistry input file. Check the <gas_chemistry>.out file for error messages.
`KINETICS ERROR: Problem getting surface chemistry info; Check that the CHEMKIN files have been processed correctly`	Indicates a possible error in the pre-processing of the surface chemistry input file. Check the <surface_chemistry>.out file for error messages.
`DASPK:...`	These messages are from the CHEMKIN-CFD transient solver, DASPK. The exact message usually contains more information about the problem.

Note: During steady-state simulations, once an iteration occurs where there are no failed cells, the effect of previously failed cells in earlier iterations is completely erased.