# # HACA Mechanism - very rough prototype # Reference: # (1) M. Frenklach, H. Wang, # "Detailed Mechanism and Modeling of Soot Particle Formation" # in Soot Formation in Combustion: Mechanisms and Models" # J. Bockhorn Ed., Springer Verlag, Heidelberg (1994). # # # HKM Notes -> The elements in the element arrays all have to be equal and # in the same order. This is a limitation of cads. units(length = 'cm', quantity = 'mol', act_energy = 'kcal/mol') #------------- the gas ------------------------------------- ideal_gas(name = 'gas', elements = 'O H C N Ar', species = 'gri30: H N2 CH3 CH4 C2H2 H2 OH H2O CO O2', initial_state = state(temperature = 1400.0, pressure = OneAtm, mole_fractions = 'H:0.01, N2:0.8899, H2:0.04, CH4:0.01 C2H2:0.01 \ OH:0.0001 H2O:0.04 O2:0.001')) #------------- bulk soot ------------------------------------- # Taken from Bensen's book. # However, entropy is negative; this is not correct. # Group contribution approach needs to be modified. Bensen has a # negative value for S here, because the group contribution is usually # lumped in with other groups which have positive S contributions. # However, for the current mechanism, bulk thermodynamics doesn't # matter since all reactions involving bulk growth or etching # are irreversible. # stoichiometric_solid(name = 'soot', elements = 'O H C N Ar', density = (3.52, 'g/cm3'), species = 'CB-CB3') species(name = 'CB-CB3', atoms = 'C:1', thermo = const_cp(t0 = (1000., 'K'), h0 = (9.22, 'kcal/mol') , s0 = (-3.02, 'cal/mol/K'), cp0 = (5.95, 'cal/mol/K') )) #------------- the diamond surface ------------------------------------- # # Site density taken from Frenklach/Wang p. 179. # ideal_interface(name = 'soot_interface', elements = 'O H C N Ar ', species = 'Csoot-* Csoot-H', reactions = 'all', phases = 'gas soot', site_density = (3.8E-9, 'mol/cm2'), initial_state = state(temperature= 1000.0, coverages = 'Csoot-*:0.1, Csoot-H:0.9')) # HKM -> Note, thermo from the following source: # 'S. J. Harris and D. G. Goodwin, 'Growth on # the reconstructed diamond (100) surface, 'J. Phys. Chem. vo. 97, # 23-28 (1993). reactions a - t are taken directly from Table II, # with thermochemistry from Table IV. # -> Thermo needs to be reviewed, as deltaG for reactions are # very important. # species(name = 'Csoot-*', atoms = 'H:0 C:1', thermo = const_cp(t0 = (1000., 'K'), h0 = (51.7, 'kcal/mol'), s0 = (19.5, 'cal/mol/K'), cp0 = (8.41, 'cal/mol/K') )) species(name = 'Csoot-H', atoms = 'H:1 C:1', thermo = const_cp(t0 = (1000., 'K'), h0 = (11.4, 'kcal/mol'), s0 = (21.0, 'cal/mol/K'), cp0 = (8.41, 'cal/mol/K')) ) # # Forward rate constant taken from Frenklach/Wang: surface_reaction( 'Csoot-H + H => Csoot-* + H2', [4.17E13, 0.0, 13.0]) surface_reaction( 'Csoot-* + H2 => Csoot-H + H', [3.9E12, 0.0, 11.0]) surface_reaction( 'Csoot-H + OH => Csoot-* + H2O', [1.0E10, 0.734, 1.43]) surface_reaction( 'Csoot-* + H2O => Csoot-H + OH', [3.68E8, 1.139, 17.1]) surface_reaction( 'Csoot-* + H => Csoot-H', [2.0E13, 0.0, 0.0]) surface_reaction( 'Csoot-* + C2H2 => Csoot-H + H + 2 CB-CB3', [8.0E7, 1.56, 3.8]) surface_reaction( 'Csoot-* + O2 + 2 CB-CB3 => Csoot-* + 2 CO', [2.2E12, 0.00, 7.5]) #surface_reaction( 'OH + Csoot-H + CB-CB3 => Csoot-* + CO + H2', [3.01577E10, 0.5, 0.0]) surface_reaction( 'OH + Csoot-H + CB-CB3 => Csoot-* + CO + H2', stick(0.13, 0.0, 0.0))