From charlesreid1

Notes on Chemkin file format

Example Chemkin file for heptane combustion can be found here:

Chemkin file format documentation can be found here:


Reactions block is designated by the word REACTIONS. Each line lists, in the following order:

  • Reaction scheme
  • A (default units: mol-cm-s-K)
  • b (no units)
  • E (default units: cal/mol)

where the constants are in the Arrhenius form,

k = A T^b \exp( -\frac{E}{RT} )

An example Reactions section of a Chemkin file format is given below.

ch4+h=>ch3+h2                            1.727e+04    3.000   8223.95
ch3+h2=>ch4+h                            6.610e+02    3.000   7744.02
ch4+oh=>ch3+h2o                          1.930e+05    2.400   2106.12
ch3+h2o=>ch4+oh                          4.820e+02    2.900  14859.94

If you want to specify the units of the constants to be something other than the default, you can specify them this way:

2CH4+O2=>2CO+4H2        7.824435194e13      0.0       0.12552
CH4+H2O=>CO+3H2         3.1E11                      0.0        0.12552
CO+H2O=>CO2+H2           2.75E12                    0.0        0.08368
2H2+O2<=>2H2O              4.44566E21            -1.0        0.16736