The following kinetic model description is input as a separate file whose name is specified after the user option NO. OF CHEMICAL REACTIONS.

The first line of input for this file is a comment line for the identification of the contents of the file. The next two lines are comment lines, indicating that the reaction mechanism model equations are to follow:

'REACTION MECHANISM EQUATION LIST'
'REACTION     REACTANT SIDE  PRODUCT SIDE'

The equations that define the reaction model follow. The number of reactions is defined in the general input section. There must be one reaction model equation per line and the number of reactions must match that specified on the NO. OF CHEMICAL REACTIONS line of the general input file. The lines consist of an integer followed by alphanumeric string used to define the forward and possibly backward reactions, as shown in the following example:

Example:

'REACTION MECHANISM EQUATION LIST'
'REACTION     REACTANT SIDE    PRODUCT SIDE'
     1       'H2 + O2      <=> 2OH'
     2       'H + O2       <=> OH + O'
     3       'OH + H2      <=> H2O + H'
     4       'O + H2       <=> OH + H'
     5       '2OH          <=> H2O + O'
     6       'H + OH + M   <=> H2O + M'
     7       '2H + M       <=> H2 + M'

Each string is read and parsed to build the stoichiometric coefficient array that defines the reaction model. The form of the equation string must follow four rules:

1) The species names used here must match exactly those specified in the Chemical Species Information section of the general input file.

2) If a "+" sign is used as part of a species name (e.g. an ion), then it must be the last character of the species name. This limitation results from the fact that the "+" sign is used to delineate species names on either the reactant or product side of the reaction string.

3) No other character may be used to designate <=> or =>. This is used to delineate the product and reactant sides of the equation. The <=> designates that the reaction progresses in both the forward and backward direction. The => designates that the reaction progresses in the forward direction only.

4) Catalytic (3rd) bodies must be designated by an M.

The next line is a comment line supplied by the user to describe forward kinetic rate input data. The constants for the Arrhenius model are to be input on the following lines as shown and have units of seconds, moles, cubic centimeters, calories, and Kelvins:

Example:

'REACTION        A     B      Ta'
    1       0.170E14  0.0   24154.6

If 'FORWARD REACTION MODEL' = 1.0 then the user must also specify the number of reactions that have arbitrary reaction orders followed by the reaction order information, i.e.

'ARBITRARY REACTION ORDERS':REAL; Number of lines required to define the arbitrary reaction orders.

'REACTION     SPECIES  ORDER': Comment line for user convenience, where:

  REACTION    :INTEGER; Reaction number of the arbitrary reaction order.
   0 = All reactions
  >0 = Specific reaction number to apply the reaction order.

  SPECIES:'STRING'; Species name to which the reaction order applies. Species name is based on the names specified in the SPECIES section of the input file.

  ORDER:REAL; Reaction order (exponent for law of mass action expression)

  Example:

  'REACTION     SPECIES  ORDER'
      22         'CH4'    0.2
      22         'O2'     1.3

'BACKWARD REACTION MODEL':REAL; Backward reaction rate coefficient model
 0.0 = Arrhenius model with elementary kinetic steps
 1.0 = Arrhenius model with global (arbitrary reaction order) steps
 2.0 = Equilibrium rate model

If 'BACKWARD REACTION MODEL' = 0.0 or 1.0 the next group of input lines are the same as for the forward reaction model as defined above.

If 'BACKWARD REACTION MODEL' = 2.0 no input is required.

'CATALYTIC BODY EFFICIENCIES':REAL; Number of lines required to define non-unity catalytic body efficiencies.

'REACTION     SPECIES  EFFICIENCY': Comment line for user convenience, where:

  REACTION:INTEGER; Reaction number associated with the catalytic body efficiency.
    0 = All catalytic body reactions.
   >0 = Specific catalytic body reaction number to apply the non-unity efficiency.

  SPECIES:'STRING'; Species name to which the catalytic body applies. Species name is based on the names specified in the SPECIES section of the input file.

  EFFICIENCY:REAL; Catalytic body efficiency

  Example:

  'CATALYTIC BODY EFFICIENCIES'   2.0 (No. of efficiencies not equal to 1.0)
  'REACTION  SPECIES EFFICIENCY'      (0 = all reactions, >0 = reaction no.)
       0      'H2'       2.5
       0      'H2O'     16.0

'PRESSURE DEPENDENT REACTIONS':REAL; Number of lines required to define the pressure-dependent reaction rates.

'REACTION     ARRHENIUS CONSTANTS       FORM   COEFFICIENTS': Comment line for user convenience, where:

  REACTION:INTEGER; Pressure-dependent reaction number (>0).

  ARRHENIUS CONSTANTS:REAL; 3 Arrhenius constants (A, b, Ta) associated with the low pressure (unimolecular/recombination fall-off reactions) or high pressure (chemically activated bimolecular reactions) reaction rate.

  FORM:'STRING'; Defines the particular form used to account for the pressure dependence. The three options are 'LIND' (Lindemann form), 'TROE' (generalized Troe form), and 'SRI' (generalized SRI form).

  COEFFICIENTS:REAL; coefficients required by the particlar pressure-dependency form chosen.
    No coefficients are required for the Lindemann form.
    alpha, T***, T*, and T** are required for the Troe form.
    a, b, c, d, and e are required for the SRI form.

    A detailed description of the Troe and SRI functional forms can be found in the following references:

    Stewart, P. H., Larson, C. W., Golden, D. M., Combustion and Flame, Vol. 75, No. 25, 1989.
    Gilbert, R. G., Luther, K., and Troe, J., Ber. Bunsenges. Phys. Chem., Vol. 87, No. 169, 1983.

  Example:

  'REACTION     ARRHENIUS CONSTANTS       FORM   COEFFICIENTS'
      16    3.482E16  -0.411   -561.370  'TROE'  0.500 1.00E-30 1.00E+30 1.00E+30
      17    1.202E17   0.000  22907.917  'TROE'  0.500 1.00E-30 1.00E+30 1.00E+30

The distinction between unimolecular/recombination fall-off reactions and chemically activated bimolecular reactions is determined based on how the catalytic body is included in the description of the reaction as given in the 'REACTION MECHANISM EQUATION LIST'

If the reaction is a unimolecular/recombination fall-off reaction, then the high pressure reaction rates should be given in the 'FORWARD REACTION MODEL' section above, and the catalytic body must not be included in the 'REACTION MECHANISM EQUATION LIST'

If the reaction is a chemically activated bimolecular reaction, then the low pressure reaction rates should be given in the 'FORWARD REACTION MODEL' section above, and the catalytic body must be included in the 'REACTION MECHANISM EQUATION LIST'

SAMPLE CHEMICAL KINETIC MODEL INPUT

SAMPLE 1:

'****** NASA Langely 7 species / 7 reaction hydrogen air kinetic model ******'
'REACTION MECHANISM EQUATION LIST'
'REACTION      REACTANT SIDE     PRODUCT SIDE'
     1        'H2   + O2      <=> 2 OH'
     2        'H    + O2      <=> OH   + O'
     3        'OH   + H2      <=> H2O  + H'
     4        'O    + H2      <=> OH   + H'
     5        'OH   + OH      <=> H2O  + O'
     6        'H    + OH  + M <=> H2O  + M'
     7        'H    + H   + M <=> H2   + M'
'FORWARD REACTION MODEL'        0.0 (0=Arrhenius, 1=Global)
'REACTION      A         B      Ta   kf=A*T^B*e^(-Ta/T)'
     1      1.70E13     0.0   24154.6
     2      1.20E17    -0.91   8309.7
     3      2.20E13     0.0    2591.6
     4      5.06E04     2.67   3165.3
     5      6.30E12     0.0     548.5
     6      2.21E22    -2.0       0.0
     7      7.30E17    -1.0       0.0
'BACKWARD REACTION MODEL'       2.0 (0=Arrhenius, 1=Global, 2=Equilibrium)
'CATALYTIC BODY EFFICIENCIES'   2.0 (No. of efficiencies not equal to 1.0)
'REACTION  SPECIES EFFICIENCY'      (0 = all reactions, >0 = reaction no.)
     0      'H2'       2.5
     0      'H2O'     16.0

SAMPLE 2:

'****** Westbrook 12 species / 22 reaction methane air kinetic model ******'
'REACTION MECHANISM EQUATION LIST'
'REACTION     REACTANT SIDE     PRODUCT SIDE'
     1        'H    + O2      <=> O    + OH'
     2        'H2   + O       <=> H    + OH'
     3        'O    + H2O     <=> OH   + OH'
     4        'OH   + H2      <=> H    + H2O'
     5        'O    + HO2     <=> O2   + OH'
     6        'H    + HO2     <=> OH   + OH'
     7        'H    + HO2     <=> H2   + O2'
     8        'OH   + HO2     <=> H2O  + O2'
     9        'HO2  + HO2     <=> H2O2 + O2'
    10        'HO2  + H2      <=> H2O2 + H'
    11        'H2O2 + OH      <=> H2O  + HO2'
    12        'CO   + OH      <=> CO2  + H'
    13        'CO   + O2      <=> CO2  + O'
    14        'CO   + HO2     <=> CO2  + OH'
    15        'H    + O2  + M <=> HO2  + M'
    16        'H2O2 + M       <=> OH   + OH  + M'
    17        'OH   + M       <=> O    + H   + M'
    18        'O2   + M       <=> O    + O   + M'
    19        'H2   + M       <=> H    + H   + M'
    20        'H2O  + M       <=> H    + OH  + M'
    21        'CO   + O   + M <=> CO2  + M'
    22        'CH4  + 0.5 O2   => CO   + 2 H2'
'FORWARD REACTION MODEL'        1.0 (0=Arrhenius, 1=Global)
'REACTION      A        B      Ta    kf=A*T^B*e^(-Ta/T)'
     1      2.20E14    0.0   8455.0
     2      1.80E10    1.0   4479.1
     3      6.80e13    0.0   9260.2
     4      2.20e13    0.0   2566.7
     5      5.00e13    0.0    503.3
     6      2.50e14    0.0    956.2
     7      2.50e13    0.0    352.3
     8      5.00e13    0.0    503.3
     9      1.00E13    0.0    503.3
    10      7.30E11    0.0   9411.2
    11      1.00E13    0.0    905.9
    12      1.50E07    1.3   -402.6
    13      3.10E11    0.0  18923.0
    14      1.50E14    0.0  11927.5
    15      1.50E15    0.0   -503.3
    16      1.20E17    0.0  22898.8
    17      8.00E19   -1.0  52189.2
    18      5.10E15    0.0  57876.2
    19      2.20E14    0.0  48314.0
    20      2.20E16    0.0  52843.5
    21      5.90E15    0.0   2063.4
    22      2.06E14    0.0  24358.3
'ARBITRARY REACTION ORDERS'     2.0 (No. of arbitrary reaction orders)
'REACTION     SPECIES  ORDER'       (0 = all reactions, >0 = reaction no.)
    22         'CH4'    0.2
    22         'O2'     1.3
'BACKWARD REACTION MODEL'       2.0 (0=Arrhenius, 1=Global, 2=Equilibrium)
'CATALYTIC BODY EFFICIENCIES'   0.0 (No. of efficiencies not equal to 1.0)

SAMPLE 3:

'****** Westbrook 9 species / 19 reaction hydrogen air kinetic model ******'
'REACTION MECHANISM EQUATION LIST'
'REACTION     REACTANT SIDE     PRODUCT SIDE'
     1        'H    + O2      <=> O    + OH'
     2        'H2   + O       <=> H    + OH'
     3        'OH   + H2      <=> H    + H2O'
     4        'O    + H2O     <=> OH   + OH'
     5        'H    + HO2     <=> H2   + O2'
     6        'H    + HO2     <=> OH   + OH'
     7        'O    + HO2     <=> O2   + OH'
     8        'OH   + HO2     <=> H2O  + O2'
     9        'HO2  + HO2     <=> H2O2 + O2'
    10        'HO2  + HO2     <=> H2O2 + O2'
    11        'H2O2 +  H      <=> H2O  + OH'
    12        'H2O2 +  H      <=> HO2  + H2'
    13        'H2O2 +  O      <=> HO2  + OH'
    14        'H2O2 + OH      <=> HO2  + H2O'
    15        'H2O2 + OH      <=> HO2  + H2O'
    16        'H    + O2      <=> HO2'
    17        'H2O2           <=> OH  + OH'
    18        'H    +  H  + M <=> H2   + M'
    19        'O    +  O  + M <=> O2   + M'
    20        'O    +  H  + M <=> OH   + M'
    21        'H    + OH  + M <=> H2O  + M'
'FORWARD REACTION MODEL'        0.0 (0=Arrhenius, 1=Global)
'REACTION      A        B       Ta   kf=A*T^B*e^(-Ta/T)'
     1      1.915E14   0.00   8277.059
     2      5.080E04   2.67   3167.838
     3      2.160E08   1.51   1726.905
     4      2.970E06   2.02   6746.508
     5      1.660E13   0.00    414.356
     6      7.079E13   0.00    148.524
     7      3.250E13   0.00      0.000
     8      2.890E13   0.00   -250.225
     9      4.200E14   0.00   6031.580
    10      1.300E11   0.00   -820.154
    11      2.410E13   0.00   1998.779
    12      6.025E13   0.00   4002.593
    13      9.550E06   2.00   1998.779
    14      1.000E12   0.00      0.000
    15      5.800E14   0.00   4811.670
    16      1.475E12   0.60      0.000
    17      2.951E14   0.00  24383.089
    18      1.146E20  -1.68    412.846
    19      6.165E15  -0.50      0.000
    20      4.714E18  -1.00      0.000
    21      4.500E22  -2.00      0.000
'BACKWARD REACTION MODEL'       0.0 (0=Arrhenius, 1=Global, 2=Equilibrium)
'REACTION      A        B       Ta   kf=A*T^B*e^(-Ta/T)'
     1      5.481E11   0.39   -147.517
     2      2.667E04   2.65   2456.937
     3      2.298E09   1.41   9223.583
     4      1.465E05   2.11  -1462.079
     5      3.164E12   0.35  27947.659
     6      2.027E10   0.72  18547.862
     7      3.252E12   0.33  26824.920
     8      5.861E13   0.24  34779.757
     9      4.634E16  -0.35  25510.861
    10      1.434E13  -0.35  18658.625
    11      1.269E08   1.31  35952.844
    12      1.041E11   0.70  12058.124
    13      8.660E03   2.68   9344.417
    14      1.838E10   0.59  15552.210
    15      1.066E13   0.59  20365.391
    16      3.090E12   0.53  24604.615
    17      3.656E08   1.14  -1300.968
    18      4.577E19  -1.40  52562.343
    19      4.515E17  -0.64  59862.669
    20      9.880E17  -0.74  51404.360
    21      1.912E23  -1.83  59661.280
'CATALYTIC BODY EFFICIENCIES'  12.0 (No. of efficiencies not equal to 1.0)
'REACTION  SPECIES EFFICIENCY'      (0 = all reactions, >0 = reaction no.)
     16     'H2'      1.30
     16     'H2O'     14.0
     17     'H2'      2.50
     17     'H2O'     12.0
     18     'H2'      2.50
     18     'H2O'     12.0
     19     'H2'      2.50
     19     'H2O'     12.0
     20     'H2'      2.50
     20     'H2O'     12.0
     21     'H2'      0.73
     21     'H2O'     12.0
'REACTION      ARRHENIUS CONSTANTS       FORM   COEFFICIENTS'
     16    3.482E16  -0.411   -561.370  'TROE'  0.500 1.00E-30 1.00E+30 1.00E+30
     17    1.202E17   0.000  22907.917  'TROE'  0.500 1.00E-30 1.00E+30 1.00E+30