Chemical Kinetics¶
Kinetics Managers¶
Kinetics¶
- class cantera.Kinetics(*args, **kwargs)¶
Bases:
_SolutionBaseInstances of class
Kineticsare responsible for evaluating reaction rates of progress, species production rates, and other quantities pertaining to a reaction mechanism.- add_reaction(self, Reaction rxn)¶
Add a new reaction to this phase.
- creation_rates¶
Creation rates for each species. [kmol/m^3/s] for bulk phases or [kmol/m^2/s] for surface phases.
- creation_rates_ddC¶
Calculate derivatives of species creation rates with respect to molar concentration at constant temperature, pressure and mole fractions.
Warning: this property is an experimental part of the Cantera API and may be changed or removed without notice.
- creation_rates_ddP¶
Calculate derivatives of species creation rates with respect to pressure at constant temperature, molar concentration and mole fractions.
- creation_rates_ddT¶
Calculate derivatives of species creation rates with respect to temperature at constant pressure, molar concentration and mole fractions.
- creation_rates_ddX¶
Calculate derivatives for species creation rates with respect to species concentrations at constant temperature, pressure and molar concentration. For sparse output, set
ct.use_sparse(True).Note that for derivatives with respect to \(X_i\), all other \(X_j\) are held constant, rather than enforcing \(\sum X_j = 1\).
Warning: this property is an experimental part of the Cantera API and may be changed or removed without notice.
- delta_enthalpy¶
Change in enthalpy for each reaction [J/kmol].
- delta_entropy¶
Change in entropy for each reaction [J/kmol/K].
- delta_gibbs¶
Change in Gibbs free energy for each reaction [J/kmol].
- delta_standard_enthalpy¶
Change in standard-state enthalpy (independent of composition) for each reaction [J/kmol].
- delta_standard_entropy¶
Change in standard-state entropy (independent of composition) for each reaction [J/kmol/K].
- delta_standard_gibbs¶
Change in standard-state Gibbs free energy (independent of composition) for each reaction [J/kmol].
- derivative_settings¶
Property setting behavior of derivative evaluation.
For
GasKinetics, the following keyword/value pairs are supported:skip-third-bodies(boolean) … ifFalse(default), third body concentrations are considered for the evaluation of derivativesskip-falloff(boolean) … ifTrue(default), third-body effects on reaction rates are not considered.rtol-delta(double) … relative tolerance used to perturb properties when calculating numerical derivatives. The default value is 1e-8.
Derivative settings are updated using a dictionary:
>>> gas.derivative_settings = {"skip-falloff": True}
Passing an empty dictionary will reset all values to their defaults.
- destruction_rates¶
Destruction rates for each species. [kmol/m^3/s] for bulk phases or [kmol/m^2/s] for surface phases.
- destruction_rates_ddC¶
Calculate derivatives of species destruction rates with respect to molar concentration at constant temperature, pressure and mole fractions.
Warning: this property is an experimental part of the Cantera API and may be changed or removed without notice.
- destruction_rates_ddP¶
Calculate derivatives of species destruction rates with respect to pressure at constant temperature, molar concentration and mole fractions.
- destruction_rates_ddT¶
Calculate derivatives of species destruction rates with respect to temperature at constant pressure, molar concentration and mole fractions.
- destruction_rates_ddX¶
Calculate derivatives for species destruction rates with respect to species concentrations at constant temperature, pressure and molar concentration. For sparse output, set
ct.use_sparse(True).Note that for derivatives with respect to \(X_i\), all other \(X_j\) are held constant, rather than enforcing \(\sum X_j = 1\).
Warning: this property is an experimental part of the Cantera API and may be changed or removed without notice.
- equilibrium_constants¶
Equilibrium constants in concentration units for all reactions.
- forward_rate_constants¶
Forward rate constants for all reactions. The computed values include all temperature-dependent, pressure-dependent, and third body contributions. Units are a combination of kmol, m^3 and s, that depend on the rate expression for the reaction.
Deprecated since version 2.6: Behavior to change after Cantera 2.6; for Cantera 2.6, rate constants of three-body reactions are multiplied with third-body concentrations (no change to legacy behavior). After Cantera 2.6, results will no longer include third-body concentrations and be consistent with conventional definitions (see Eq. 9.75 in Kee, Coltrin, and Glarborg, Chemically Reacting Flow, Wiley Interscience, 2003). To switch to new behavior, run
ct.use_legacy_rate_constants(False).
- forward_rate_constants_ddC¶
Calculate derivatives for forward rate constants with respect to molar concentration at constant temperature, pressure and mole fractions.
Warning: this property is an experimental part of the Cantera API and may be changed or removed without notice.
- forward_rate_constants_ddP¶
Calculate derivatives for forward rate constants with respect to pressure at constant temperature, molar concentration and mole fractions.
- forward_rate_constants_ddT¶
Calculate derivatives for forward rate constants with respect to temperature at constant pressure, molar concentration and mole fractions.
- forward_rates_of_progress¶
Forward rates of progress for the reactions. [kmol/m^3/s] for bulk phases or [kmol/m^2/s] for surface phases.
- forward_rates_of_progress_ddC¶
Calculate derivatives for forward rates-of-progress with respect to molar concentration at constant temperature, pressure and mole fractions.
Warning: this property is an experimental part of the Cantera API and may be changed or removed without notice.
- forward_rates_of_progress_ddP¶
Calculate derivatives for forward rates-of-progress with respect to pressure at constant temperature, molar concentration and mole fractions.
- forward_rates_of_progress_ddT¶
Calculate derivatives for forward rates-of-progress with respect to temperature at constant pressure, molar concentration and mole fractions.
- forward_rates_of_progress_ddX¶
Calculate derivatives for forward rates-of-progress with respect to species concentrations at constant temperature, pressure and molar concentration. For sparse output, set
ct.use_sparse(True).Note that for derivatives with respect to \(X_i\), all other \(X_j\) are held constant, rather than enforcing \(\sum X_j = 1\).
Warning: this property is an experimental part of the Cantera API and may be changed or removed without notice.
- heat_production_rates¶
Get the volumetric heat production rates [W/m^3] on a per-reaction basis. The sum over all reactions results in the total volumetric heat release rate. Example: C. K. Law: Combustion Physics (2006), Fig. 7.8.6
>>> gas.heat_production_rates[1] # heat production rate of the 2nd reaction
- heat_release_rate¶
Get the total volumetric heat release rate [W/m^3].
- is_reversible(self, int i_reaction)¶
True if reaction
i_reactionis reversible.Deprecated since version 2.6: Replaced by property
Reaction.reversible. Example:gas.is_reversible(0)is replaced bygas.reaction(0).reversible
- kinetics_model¶
Return type of kinetics.
- kinetics_species_index(self, species, int phase=0)¶
The index of species
speciesof phasephasewithin arrays returned by methods of classKinetics. Ifspeciesis a string, thephaseargument is unused.
- kinetics_species_name(self, k)¶
Name of the species with index
kin the arrays returned by methods of classKinetics.
- kinetics_species_names¶
A list of all species names, corresponding to the arrays returned by methods of class
Kinetics.
- modify_reaction(self, int irxn, Reaction rxn)¶
Modify the
Reactionwith indexirxnto have the same rate parameters asrxn.rxnmust have the same reactants and products and be of the same type (for example,ElementaryReaction,FalloffReaction,PlogReaction, etc.) as the existing reaction. This method does not modify the third-body efficiencies, reaction orders, or reversibility of the reaction.
- multiplier(self, int i_reaction)¶
A scaling factor applied to the rate coefficient for reaction
i_reaction. Can be used to carry out sensitivity analysis or to selectively disable a particular reaction. Seeset_multiplier.
- n_phases¶
Number of phases in the reaction mechanism.
- n_reactions¶
Number of reactions in the reaction mechanism.
- n_total_species¶
Total number of species in all phases participating in the kinetics mechanism.
- net_production_rates¶
Net production rates for each species. [kmol/m^3/s] for bulk phases or [kmol/m^2/s] for surface phases.
- net_production_rates_ddC¶
Calculate derivatives of species net production rates with respect to molar density at constant temperature, pressure and mole fractions.
Warning: this property is an experimental part of the Cantera API and may be changed or removed without notice.
- net_production_rates_ddP¶
Calculate derivatives of species net production rates with respect to pressure at constant temperature, molar concentration and mole fractions.
- net_production_rates_ddT¶
Calculate derivatives of species net production rates with respect to temperature at constant pressure, molar concentration and mole fractions.
- net_production_rates_ddX¶
Calculate derivatives for species net production rates with respect to species concentrations at constant temperature, pressure and molar concentration. For sparse output, set
ct.use_sparse(True).Note that for derivatives with respect to \(X_i\), all other \(X_j\) are held constant, rather than enforcing \(\sum X_j = 1\).
Warning: this property is an experimental part of the Cantera API and may be changed or removed without notice.
- net_rates_of_progress¶
Net rates of progress for the reactions. [kmol/m^3/s] for bulk phases or [kmol/m^2/s] for surface phases.
- net_rates_of_progress_ddC¶
Calculate derivatives for net rates-of-progress with respect to molar concentration at constant temperature, pressure and mole fractions.
Warning: this property is an experimental part of the Cantera API and may be changed or removed without notice.
- net_rates_of_progress_ddP¶
Calculate derivatives for net rates-of-progress with respect to pressure at constant temperature, molar concentration and mole fractions.
- net_rates_of_progress_ddT¶
Calculate derivatives for net rates-of-progress with respect to temperature at constant pressure, molar concentration and mole fractions.
- net_rates_of_progress_ddX¶
Calculate derivatives for net rates-of-progress with respect to species concentrations at constant temperature, pressure and molar concentration. For sparse output, set
ct.use_sparse(True).Note that for derivatives with respect to \(X_i\), all other \(X_j\) are held constant, rather than enforcing \(\sum X_j = 1\).
Warning: this property is an experimental part of the Cantera API and may be changed or removed without notice.
- product_stoich_coeff(self, k_spec, int i_reaction)¶
The stoichiometric coefficient of species
k_specas a product in reactioni_reaction.
- product_stoich_coeffs(self)¶
The array of product stoichiometric coefficients. Element [k,i] of this array is the product stoichiometric coefficient of species k in reaction i.
Deprecated since version 2.6: Behavior to change after Cantera 2.6; for new behavior, see property
Kinetics.reactant_stoich_coeffs3.
- product_stoich_coeffs3¶
The array of product stoichiometric coefficients. Element
[k,i]of this array is the product stoichiometric coefficient of specieskin reactioni.For sparse output, set
ct.use_sparse(True).
- product_stoich_coeffs_reversible¶
The array of product stoichiometric coefficients of reversible reactions. Element
[k,i]of this array is the product stoichiometric coefficient of specieskin reactioni.For sparse output, set
ct.use_sparse(True).
- products(self, int i_reaction)¶
The products portion of the reaction equation
Deprecated since version 2.6: Replaced by property
Reaction.products. Example:gas.products(0)is replaced bygas.reaction(0).products
- reactant_stoich_coeff(self, k_spec, int i_reaction)¶
The stoichiometric coefficient of species
k_specas a reactant in reactioni_reaction.
- reactant_stoich_coeffs(self)¶
The array of reactant stoichiometric coefficients. Element [k,i] of this array is the reactant stoichiometric coefficient of species k in reaction i.
Deprecated since version 2.6: Behavior to change after Cantera 2.6; for new behavior, see property
Kinetics.reactant_stoich_coeffs3.
- reactant_stoich_coeffs3¶
The array of reactant stoichiometric coefficients. Element
[k,i]of this array is the reactant stoichiometric coefficient of specieskin reactioni.For sparse output, set
ct.use_sparse(True).
- reactants(self, int i_reaction)¶
The reactants portion of the reaction equation
Deprecated since version 2.6: Replaced by property
Reaction.reactants. Example:gas.reactants(0)is replaced bygas.reaction(0).reactants
- reaction(self, int i_reaction)¶
Return a
Reactionobject representing the reaction with indexi_reaction. Changes to this object do not affect theKineticsorSolutionobject until themodify_reactionfunction is called.
- reaction_equation(self, int i_reaction)¶
The equation for the specified reaction. See also
reaction_equations.Deprecated since version 2.6: Replaced by property
Reaction.equation. Example:gas.reaction_equation(0)is replaced bygas.reaction(0).equation
- reaction_equations(self, indices=None)¶
Returns a list containing the reaction equation for all reactions in the mechanism if
indicesis unspecified, or the equations for each reaction in the sequenceindices. For example:>>> gas.reaction_equations() ['2 O + M <=> O2 + M', 'O + H + M <=> OH + M', 'O + H2 <=> H + OH', ...] >>> gas.reaction_equations([2,3]) ['O + H + M <=> OH + M', 'O + H2 <=> H + OH']
See also
reaction_equation.
- reaction_phase_index¶
The index of the phase where the reactions occur.
- reaction_type(self, int i_reaction)¶
Type code of reaction
i_reaction.Deprecated since version 2.6: Replaced by properties
Reaction.typeandReaction.rate.type. Example:gas.reaction_type(0)is replaced bygas.reaction(0).reaction_typeandgas.reaction(0).rate.type
- reactions(self)¶
Return a list of all
Reactionobjects. Changes to these objects do not affect theKineticsorSolutionobject until themodify_reactionfunction is called.
- reverse_rate_constants¶
Reverse rate constants for all reactions. The computed values include all temperature-dependent, pressure-dependent, and third body contributions. Units are a combination of kmol, m^3 and s, that depend on the rate expression for the reaction.
Deprecated since version 2.6: Behavior to change after Cantera 2.6; for Cantera 2.6, rate constants of three-body reactions are multiplied with third-body concentrations (no change to legacy behavior). After Cantera 2.6, results will no longer include third-body concentrations and be consistent with conventional definitions (see Eq. 9.75 in Kee, Coltrin and Glarborg, Chemically Reacting Flow, Wiley Interscience, 2003). To switch to new behavior, run
ct.use_legacy_rate_constants(False).
- reverse_rates_of_progress¶
Reverse rates of progress for the reactions. [kmol/m^3/s] for bulk phases or [kmol/m^2/s] for surface phases.
- reverse_rates_of_progress_ddC¶
Calculate derivatives for reverse rates-of-progress with respect to molar concentration at constant temperature, pressure and mole fractions.
Warning: this property is an experimental part of the Cantera API and may be changed or removed without notice.
- reverse_rates_of_progress_ddP¶
Calculate derivatives for reverse rates-of-progress with respect to pressure at constant temperature, molar concentration and mole fractions.
- reverse_rates_of_progress_ddT¶
Calculate derivatives for reverse rates-of-progress with respect to temperature at constant pressure, molar concentration and mole fractions.
- reverse_rates_of_progress_ddX¶
Calculate derivatives for reverse rates-of-progress with respect to species concentrations at constant temperature, pressure and molar concentration. For sparse output, set
ct.use_sparse(True).Note that for derivatives with respect to \(X_i\), all other \(X_j\) are held constant, rather than enforcing \(\sum X_j = 1\).
Warning: this property is an experimental part of the Cantera API and may be changed or removed without notice.
- set_multiplier(self, double value, int i_reaction=-1)¶
Set the multiplier for for reaction
i_reactiontovalue. Ifi_reactionis not specified, then the multiplier for all reactions is set tovalue. Seemultiplier.
- third_body_concentrations¶
Effective third-body concentrations used by individual reactions; values are only defined for reactions involving third-bodies and are set to not-a-number otherwise.
InterfaceKinetics¶
- class cantera.InterfaceKinetics(infile='', name='', adjacent=(), *args, **kwargs)¶
Bases:
KineticsA kinetics manager for heterogeneous reaction mechanisms. The reactions are assumed to occur at an interface between bulk phases.
- advance_coverages(self, double dt, double rtol=1e-7, double atol=1e-14, double max_step_size=0, int max_steps=20000, int max_error_test_failures=7)¶
This method carries out a time-accurate advancement of the surface coverages for a specified amount of time.
- advance_coverages_to_steady_state(self)¶
This method advances the surface coverages to steady state.
- get_creation_rates(self, phase)¶
Creation rates for each species in phase
phase. Use thecreation_ratesproperty to get the creation rates for species in all phases.
- get_destruction_rates(self, phase)¶
Destruction rates for each species in phase
phase. Use thedestruction_ratesproperty to get the destruction rates for species in all phases.
- get_net_production_rates(self, phase)¶
Net production rates for each species in phase
phase. Use thenet_production_ratesproperty to get the net production rates for species in all phases.
- phase_index(self, phase)¶
Get the index of the phase
phase, wherephasemay specified using the phase object, the name, or the index itself.
- write_yaml(self, filename, phases=None, units=None, precision=None, skip_user_defined=None)¶
Reactions¶
These classes contain the definition of a single reaction, independent of a specific
Kinetics object. For legacy objects (CTI/XML input), each class integrates associated
rate expressions, whereas for the new, YAML-based implementation, reaction rate
evaluation is handled by dedicated ReactionRate objects.
Reaction¶
- class cantera.Reaction(reactants=None, products=None, rate=None, equation=None, *, init=True, legacy=False, **kwargs)¶
Bases:
objectA class which stores data about a reaction and its rate parameterization so that it can be added to a
Kineticsobject.- Parameters
reactants – Value used to set
reactantsproducts – Value used to set
productsrate –
The rate parameterization for the reaction, given as one of the following:
a
ReactionRateobjecta
dictcontaining the parameters needed to construct aReactionRateobject, with keys corresponding to the YAML formata
dictcontaining Arrhenius parameters (A,b, andEa)
equation – The reaction equation, used to set the reactants and products if values for those arguments are not provided.
Examples:
R = ct.Reaction({"O": 1, "H2": 1}, {"H": 1, "OH": 1}, ct.ArrheniusRate(38.7, 2.7, 26191840.0)) R = ct.Reaction(equation="O + H2 <=> H + OH", rate={"A": 38.7, "b", 2.7, "Ea": 26191840.0}) R = ct.Reaction(equation="HO2 <=> OH + O", rate=ChebyshevRate(...))
The static methods
list_from_file,list_from_yaml,listFromCti, andlistFromXmlcan be used to create lists ofReactionobjects from existing definitions in the YAML, CTI, or XML formats. All of the following will produce a list of the 325 reactions which make up the GRI 3.0 mechanism:R = ct.Reaction.list_from_file("gri30.yaml", gas) R = ct.Reaction.listFromCti(open("path/to/gri30.cti").read()) R = ct.Reaction.listFromXml(open("path/to/gri30.xml").read())
where
gasis aSolutionobject with the appropriate thermodynamic model, which is theideal-gasmodel in this case.The static method
list_from_yamlcan be used to create lists ofReactionobjects from a YAML list:rxns = ''' - equation: O + H2 <=> H + OH rate-constant: {A: 3.87e+04, b: 2.7, Ea: 6260.0} - equation: O + HO2 <=> OH + O2 rate-constant: {A: 2.0e+13, b: 0.0, Ea: 0.0} ''' R = ct.Reaction.list_from_yaml(rxns, gas)
The methods
from_yaml,fromCti, andfromXmlcan be used to create individualReactionobjects from definitions in these formats. In the case of using YAML or CTI definitions, it is important to verify that either the pre-exponential factor and activation energy are supplied in SI units, or that they have their units specified:R = ct.Reaction.from_yaml('''{equation: O + H2 <=> H + OH, rate-constant: {A: 3.87e+04 cm^3/mol/s, b: 2.7, Ea: 6260 cal/mol}}''', gas) R = ct.Reaction.fromCti('''reaction('O + H2 <=> H + OH', [3.87e1, 2.7, 2.619184e7])''') R = ct.Reaction.fromCti('''reaction('O + H2 <=> H + OH', [(3.87e4, 'cm3/mol/s'), 2.7, (6260, 'cal/mol')])''')
- ID¶
Get/Set the identification string for the reaction, which can be used in filtering operations.
- Pmax¶
Maximum pressure [K] for the Chebyshev fit
Deprecated since version 2.6: This property is for temporary backwards-compatibility with the deprecated
ChebyshevReactionclass. Replaced byReaction.rate.pressure_range[1]for reactions where the rate is a aChebyshevRate.
- Pmin¶
Minimum pressure [Pa] for the Chebyshev fit
Deprecated since version 2.6: This property is for temporary backwards-compatibility with the deprecated
ChebyshevReactionclass. Replaced byReaction.rate.pressure_range[0]for reactions where the rate is a aChebyshevRate.
- Tmax¶
Maximum temperature [K] for the Chebyshev fit
Deprecated since version 2.6: This property is for temporary backwards-compatibility with the deprecated
ChebyshevReactionclass. Replaced byReaction.rate.temperature_range[1]for reactions where the rate is aChebyshevRate.
- Tmin¶
Minimum temperature [K] for the Chebyshev fit
Deprecated since version 2.6: This property is for temporary backwards-compatibility with the deprecated
ChebyshevReactionclass. Replaced byReaction.rate.temperature_range[0]for reactions where the rate is aChebyshevRate.
- allow_negative_orders¶
Get/Set a flag which is
Trueif negative reaction orders are allowed. Default isFalse.
- allow_negative_pre_exponential_factor¶
Get/Set whether the rate coefficient is allowed to have a negative pre-exponential factor.
Deprecated since version 2.6: To be deprecated with version 2.6, and removed thereafter. Replaced by property
ArrheniusRateBase.allow_negative_pre_exponential_factor.
- allow_nonreactant_orders¶
Get/Set a flag which is
Trueif reaction orders can be specified for non-reactant species. Default isFalse.
- clear_user_data(self)¶
Clear all saved input data, so that the data given by
input_dataorSolution.write_yamlwill only include values generated by Cantera based on the current object state.
- coeffs¶
2D array of Chebyshev coefficients of size
(n_temperature, n_pressure).Deprecated since version 2.6: This property is for temporary backwards-compatibility with the deprecated
ChebyshevReactionclass. Replaced byReaction.rate.datafor reactions where the rate is aChebyshevRate.
- coverage_deps¶
Get/Set a dict containing adjustments to the Arrhenius rate expression dependent on surface species coverages. The keys of the dict are species names, and the values are tuples specifying the three coverage parameters
(a, m, E)which are the modifiers for the pre-exponential factor [m, kmol, s units], the temperature exponent [nondimensional], and the activation energy [J/kmol], respectively.Deprecated since version 2.6: This property is for temporary backwards-compatibility with the deprecated
InterfaceReactionclass. Replaced byReaction.rate.coverage_dependenciesfor reactions where the rate is aInterfaceArrheniusRateorStickingArrheniusRate.
- duplicate¶
Get/Set a flag which is
Trueif this reaction is marked as a duplicate orFalseotherwise.
- equation¶
A string giving the chemical equation for this reaction. Determined automatically based on
reactantsandproducts.
- static fromCti(text)¶
Create a Reaction object from its CTI string representation.
Deprecated since version 2.5: The CTI input format is deprecated and will be removed in Cantera 3.0.
- static fromXml(text)¶
Create a Reaction object from its XML string representation.
Deprecated since version 2.5: The XML input format is deprecated and will be removed in Cantera 3.0.
- fromYaml(type cls, text, Kinetics kinetics=None)¶
Create a
Reactionobject from its YAML string representation.Deprecated since version 2.6: To be deprecated with version 2.6, and removed thereafter. Replaced by
Reaction.from_yaml.
- from_dict(type cls, data, Kinetics kinetics)¶
Create a
Reactionobject from a dictionary corresponding to its YAML representation.An example for the creation of a Reaction from a dictionary is:
rxn = Reaction.from_dict( {"equation": "O + H2 <=> H + OH", "rate-constant": {"A": 38.7, "b": 2.7, "Ea": 26191840.0}}, kinetics=gas)
In the example,
gasis a Kinetics (or Solution) object.- Parameters
data – A dictionary corresponding to the YAML representation.
kinetics – A
Kineticsobject whose associated phase(s) contain the species involved in the reaction.
- from_yaml(type cls, text, Kinetics kinetics)¶
Create a
Reactionobject from its YAML string representation.An example for the creation of a Reaction from a YAML string is:
rxn = Reaction.from_yaml(''' equation: O + H2 <=> H + OH rate-constant: {A: 38.7, b: 2.7, Ea: 6260.0 cal/mol} ''', kinetics=gas)
In the example,
gasis a Kinetics (or Solution) object.- Parameters
text – The YAML reaction string.
kinetics – A
Kineticsobject whose associated phase(s) contain the species involved in the reaction.
- input_data¶
Get input data for this reaction with its current parameter values, along with any user-specified data provided with its input (YAML) definition.
- is_sticking_coefficient¶
Get/Set a boolean indicating if the rate coefficient for this reaction is expressed as a sticking coefficient rather than the forward rate constant.
Deprecated since version 2.6: This property is for temporary backwards-compatibility with the deprecated
InterfaceReactionclass. Replaced by dedicated rate objectsInterfaceArrheniusRateandStickingArrheniusRate.
- static listFromCti(text)¶
Create a list of
Reactionobjects from all the reactions defined in a CTI string.Deprecated since version 2.5: The CTI input format is deprecated and will be removed in Cantera 3.0.
- static listFromFile(filename, Kinetics kinetics=None, section=u'reactions')¶
Create a list of Reaction objects from all of the reactions defined in a YAML, CTI, or XML file.
For YAML input files, a
Kineticsobject is required as the second argument, and reactions from the sectionsectionwill be returned.Directories on Cantera’s input file path will be searched for the specified file.
In the case of an XML file, the
<reactions>nodes are assumed to be children of the<reactionsData>node in a document with a<ctml>root node, as in the XML files produced by conversion from CTI files.Deprecated since version 2.5: The CTI and XML input formats are deprecated and will be removed in Cantera 3.0.
Deprecated since version 2.6: To be removed after Cantera 2.6. Replaced by
Reaction.list_from_file.
- static listFromXml(text)¶
Create a list of Reaction objects from all the reaction defined in an XML string. The
<reaction>nodes are assumed to be children of the<reactionData>node in a document with a<ctml>root node, as in the XML files produced by conversion from CTI files.Deprecated since version 2.5: The XML input format is deprecated and will be removed in Cantera 3.0.
- static listFromYaml(text, Kinetics kinetics)¶
Create a list of
Reactionobjects from all the reactions defined in a YAML string.Deprecated since version 2.6: To be deprecated with version 2.6, and removed thereafter. Replaced by
Reaction.list_from_yaml.
- static list_from_file(filename, Kinetics kinetics, section=u'reactions')¶
Create a list of Reaction objects from all of the reactions defined in a YAML file. Reactions from the section
sectionwill be returned.Directories on Cantera’s input file path will be searched for the specified file.
- static list_from_yaml(text, Kinetics kinetics)¶
Create a list of
Reactionobjects from all the reactions defined in a YAML string.
- nPressure¶
Number of pressures over which the Chebyshev fit is computed
Deprecated since version 2.6: This property is for temporary backwards-compatibility with the deprecated
ChebyshevReactionclass. Replaced byReaction.rate.n_pressurefor reactions where the rate is a aChebyshevRate.
- nTemperature¶
Number of temperatures over which the Chebyshev fit is computed
Deprecated since version 2.6: This property is for temporary backwards-compatibility with the deprecated
ChebyshevReactionclass. Replaced byReaction.rate.n_temperaturefor reactions where the rate is aChebyshevRate.
- orders¶
Get/Set the reaction order with respect to specific species as a dict with species names as the keys and orders as the values, or as a composition string. By default, mass-action kinetics is assumed, with the reaction order for each reactant species equal to each its stoichiometric coefficient.
- product_string¶
A string representing the products side of the chemical equation for this reaction. Determined automatically based on
products.
- products¶
Get/Set the products in this reaction as a dict where the keys are species names and the values, are the stoichiometric coefficients, for example
{'CH3':1, 'H2O':1}, or as a composition string, for example'CH3:1, H2O:1'.
- rate¶
Get/Set the
ArrheniusRaterate coefficient for this reaction.
- rate_coeff_units¶
Get reaction rate coefficient units
- rates¶
For reactions with Plog rates, get/set the rate coefficients for this reaction as a list of (pressure, rate) tuples.
Deprecated since version 2.6: This property is for temporary backwards-compatibility with the deprecated
PlogReactionclass. Replaced byReaction.rate.ratesfor reactions where the rate is aPlogRate.
- reactant_string¶
A string representing the reactants side of the chemical equation for this reaction. Determined automatically based on
reactants.
- reactants¶
Get/Set the reactants in this reaction as a dict where the keys are species names and the values, are the stoichiometric coefficients, for example
{'CH4':1, 'OH':1}, or as a composition string, for example'CH4:1, OH:1'.
- reaction_type¶
Retrieve the native type name of the reaction.
- set_parameters(self, Tmin, Tmax, Pmin, Pmax, coeffs)¶
For Chebyshev reactions, simultaneously set values for
Tmin,Tmax,Pmin,Pmax, andcoeffs.Deprecated since version 2.6: This property is for temporary backwards-compatibility with the deprecated
ChebyshevReactionclass. Replaced byChebyshevRateconstructor for reactions where the rate is aChebyshevRate.
- sticking_species¶
The name of the sticking species. Needed only for reactions with multiple non-surface reactant species, where the sticking species is ambiguous.
Deprecated since version 2.6: To be deprecated with version 2.6, and removed thereafter. Replaced by property
StickingArrheniusRate.sticking_species.
- update_user_data(self, data)¶
Add the contents of the provided
dictas additional fields when generating YAML phase definition files withSolution.write_yamlor in the data returned byinput_data. Existing keys with matching names are overwritten.
- use_motz_wise_correction¶
Get/Set a boolean indicating whether to use the correction factor developed by Motz & Wise for reactions with high (near-unity) sticking coefficients when converting the sticking coefficient to a rate coefficient.
Deprecated since version 2.6: This property is for temporary backwards-compatibility with the deprecated
InterfaceReactionclass. Replaced byReaction.rate.motz_wise_correctionfor reactions where the rate is aStickingArrheniusRate.
- uses_legacy¶
Indicate whether reaction uses a legacy implementation
ElementaryReaction¶
- class cantera.ElementaryReaction(reactants=None, products=None, rate=None, equation=None, *, Kinetics kinetics=None, init=True, **kwargs)¶
Bases:
ReactionA reaction which follows mass-action kinetics with a modified Arrhenius reaction rate.
An example for the definition of an
ElementaryReactionobject is given as:rxn = ElementaryReaction( equation="O + H2 <=> H + OH", rate={"A": 38.7, "b": 2.7, "Ea": 2.619184e+07}, kinetics=gas)
The YAML description corresponding to this reaction is:
equation: O + H2 <=> H + OH rate-constant: {A: 3.87e+04 cm^3/mol/s, b: 2.7, Ea: 6260.0 cal/mol}
Deprecated since version 2.6: To be removed after Cantera 2.6. Capabilities merged directly into the base
Reactionclass.- allow_negative_pre_exponential_factor¶
Get/Set whether the rate coefficient is allowed to have a negative pre-exponential factor.
Deprecated since version 2.6: To be deprecated with version 2.6, and removed thereafter. Replaced by property
ArrheniusRateBase.allow_negative_pre_exponential_factor.
- rate¶
Get/Set the
ArrheniusRaterate coefficient for this reaction.
ThreeBodyReaction¶
- class cantera.ThreeBodyReaction(reactants=None, products=None, rate=None, equation=None, *, efficiencies=None, Kinetics kinetics=None, legacy=False, init=True, **kwargs)¶
Bases:
ElementaryReactionA reaction with a non-reacting third body “M” that acts to add or remove energy from the reacting species.
An example for the definition of an
ThreeBodyReactionobject is given as:rxn = ThreeBodyReaction( equation="2 O + M <=> O2 + M", rate={"A": 1.2e+17, "b": -1.0, "Ea": 0.0}, efficiencies={"H2": 2.4, "H2O": 15.4, "AR": 0.83}, kinetics=gas)
The YAML description corresponding to this reaction is:
equation: 2 O + M <=> O2 + M type: three-body rate-constant: {A: 1.2e+17 cm^6/mol^2/s, b: -1.0, Ea: 0.0 cal/mol} efficiencies: {H2: 2.4, H2O: 15.4, AR: 0.83}
- default_efficiency¶
Get/Set the default third-body efficiency for this reaction, used for species used for species not in
efficiencies.
- efficiencies¶
Get/Set a
dictdefining non-default third-body efficiencies for this reaction, where the keys are the species names and the values are the efficiencies.
- efficiency(self, species)¶
Get the efficiency of the third body named
speciesconsidering both the default efficiency and species-specific efficiencies.
FalloffReaction¶
- class cantera.FalloffReaction(reactants=None, products=None, rate=None, equation=None, *, efficiencies=None, Kinetics kinetics=None, init=True, legacy=False, **kwargs)¶
Bases:
ReactionA reaction that is first-order in [M] at low pressure, like a third-body reaction, but zeroth-order in [M] as pressure increases.
An example for the definition of a
FalloffReactionobject is given as:rxn = FalloffReaction( equation="2 OH (+ M) <=> H2O2 (+ M)", rate=ct.TroeRate(low=ct.Arrhenius(2.3e+12, -0.9, -7112800.0), high=ct.Arrhenius(7.4e+10, -0.37, 0), falloff_coeffs=[0.7346, 94.0, 1756.0, 5182.0]), efficiencies={"AR": 0.7, "H2": 2.0, "H2O": 6.0}, kinetics=gas)
The YAML description corresponding to this reaction is:
equation: 2 OH (+ M) <=> H2O2 (+ M) # Reaction 3 type: falloff low-P-rate-constant: {A: 2.3e+12, b: -0.9, Ea: -1700.0 cal/mol} high-P-rate-constant: {A: 7.4e+10, b: -0.37, Ea: 0.0 cal/mol} Troe: {A: 0.7346, T3: 94.0, T1: 1756.0, T2: 5182.0} efficiencies: {AR: 0.7, H2: 2.0, H2O: 6.0}
- allow_negative_pre_exponential_factor¶
Get/Set whether the rate coefficient is allowed to have a negative pre-exponential factor.
Deprecated since version 2.6: To be deprecated with version 2.6, and removed thereafter. Replaced by property
FalloffRate.allow_negative_pre_exponential_factor.
- default_efficiency¶
Get/Set the default third-body efficiency for this reaction, used for species used for species not in
efficiencies.
- efficiencies¶
Get/Set a
dictdefining non-default third-body efficiencies for this reaction, where the keys are the species names and the values are the efficiencies.
- efficiency(self, species)¶
Get the efficiency of the third body named
speciesconsidering both the default efficiency and species-specific efficiencies.
- rate¶
Get/Set the
FalloffRaterate coefficients for this reaction.
ChemicallyActivatedReaction¶
- class cantera.ChemicallyActivatedReaction¶
Bases:
FalloffReactionA reaction where the rate decreases as pressure increases due to collisional stabilization of a reaction intermediate. Like a
FalloffReaction, except that the forward rate constant is written as being proportional to the low- pressure rate constant.
PlogReaction¶
- class cantera.PlogReaction(reactants=None, products=None, rate=None, equation=None, *, Kinetics kinetics=None, init=True, **kwargs)¶
Bases:
ReactionA pressure-dependent reaction parameterized by logarithmically interpolating between Arrhenius rate expressions at various pressures.
An example for the definition of a
PlogReactionobject is given as:rxn = PlogReaction( equation="H2 + O2 <=> 2 OH", rate=[(1013.25, Arrhenius(1.2124e+16, -0.5779, 45491376.8)), (101325., Arrhenius(4.9108e+31, -4.8507, 103649395.2)), (1013250., Arrhenius(1.2866e+47, -9.0246, 166508556.0)), (10132500., Arrhenius(5.9632e+56, -11.529, 220076726.4))], kinetics=gas)
The YAML description corresponding to this reaction is:
equation: H2 + O2 <=> 2 OH type: pressure-dependent-Arrhenius rate-constants: - {P: 0.01 atm, A: 1.2124e+16, b: -0.5779, Ea: 1.08727e+04 cal/mol} - {P: 1.0 atm, A: 4.9108e+31, b: -4.8507, Ea: 2.47728e+04 cal/mol} - {P: 10.0 atm, A: 1.2866e+47, b: -9.0246, Ea: 3.97965e+04 cal/mol} - {P: 100.0 atm, A: 5.9632e+56, b: -11.529, Ea: 5.25996e+04 cal/mol}or.
ChebyshevReaction¶
- class cantera.ChebyshevReaction(reactants=None, products=None, rate=None, equation=None, *, Kinetics kinetics=None, init=True, **kwargs)¶
Bases:
ReactionA pressure-dependent reaction parameterized by a bivariate Chebyshev polynomial in temperature and pressure.
An example for the definition of a
ChebyshevReactionobject is given as:rxn = ChebyshevReaction( equation="HO2 <=> OH + O", rate={"temperature-range": [290.0, 3000.0], "pressure-range": [1e3, 1e8], "data": [[8.2883, -1.1397, -0.12059, 0.016034], [1.9764, 1.0037, 7.2865e-03, -0.030432], [0.3177, 0.26889, 0.094806, -7.6385e-03]]}, kinetics=gas)
The YAML description corresponding to this reaction is:
equation: HO2 <=> OH + O type: Chebyshev temperature-range: [290.0, 3000.0] pressure-range: [1.e-03 bar, 10. bar] data: - [8.2883, -1.1397, -0.12059, 0.016034] - [1.9764, 1.0037, 7.2865e-03, -0.030432] - [0.3177, 0.26889, 0.094806, -7.6385e-03]
Deprecated since version 2.6: To be deprecated with version 2.6, and removed thereafter. Implemented by the
Reactionclass with aChebyshevRatereaction rate.- Pmax¶
Maximum pressure [Pa] for the Chebyshev fit
Deprecated since version 2.6: To be deprecated with version 2.6, and removed thereafter. Replaced by property
ChebyshevRate.pressure_range[1].
- Pmin¶
Minimum pressure [Pa] for the Chebyshev fit
Deprecated since version 2.6: To be deprecated with version 2.6, and removed thereafter. Replaced by property
ChebyshevRate.pressure_range[0].
- Tmax¶
Maximum temperature [K] for the Chebyshev fit
Deprecated since version 2.6: To be deprecated with version 2.6, and removed thereafter. Replaced by property
ChebyshevRate.temperature_range[1].
- Tmin¶
Minimum temperature [K] for the Chebyshev fit
Deprecated since version 2.6: To be deprecated with version 2.6, and removed thereafter. Replaced by property
ChebyshevRate.temperature_range[0].
- coeffs¶
2D array of Chebyshev coefficients of size
(n_temperature, n_pressure).Deprecated since version 2.6: To be deprecated with version 2.6, and removed thereafter. Replaced by property
ChebyshevRate.data.
- nPressure¶
Number of pressures over which the Chebyshev fit is computed
Deprecated since version 2.6: To be deprecated with version 2.6, and removed thereafter. Replaced by property
ChebyshevRate.n_pressure.
- nTemperature¶
Number of temperatures over which the Chebyshev fit is computed
Deprecated since version 2.6: To be deprecated with version 2.6, and removed thereafter. Replaced by property
ChebyshevRate.n_temperature.
InterfaceReaction¶
- class cantera.InterfaceReaction(equation=None, rate=None, Kinetics kinetics=None, init=True, legacy=False, **kwargs)¶
Bases:
ElementaryReactionA reaction occurring on an
Interface(that is, a surface or an edge)- rxn = InterfaceReaction(
equation=”H(S) + O(S) <=> OH(S) + PT(S)”, rate={“A”: 3.7e+20, “b”: 0, “Ea”: 1.15e7}, kinetics=surf)
The YAML description corresponding to this reaction is:
equation: H(S) + O(S) <=> OH(S) + PT(S) rate-constant: {A: 3.7e+20, b: 0, Ea: 11500 J/mol}
Deprecated since version 2.6: To be deprecated with version 2.6, and removed thereafter. Implemented by the
Reactionclass with eitherInterfaceArrheniusRateorStickingArrheniusRatereaction rate.- coverage_deps¶
Get/Set a dict containing adjustments to the Arrhenius rate expression dependent on surface species coverages. The keys of the dict are species names, and the values are tuples specifying the three coverage parameters
(a, m, E)which are the modifiers for the pre-exponential factor [m, kmol, s units], the temperature exponent [nondimensional], and the activation energy [J/kmol], respectively.Deprecated since version 2.6: To be deprecated with version 2.6, and removed thereafter. Replaced by property
InterfaceRateBase.coverage_dependencies.
- is_sticking_coefficient¶
Get/Set a boolean indicating if the rate coefficient for this reaction is expressed as a sticking coefficient rather than the forward rate constant.
Deprecated since version 2.6: To be deprecated with version 2.6, and removed thereafter. Replaced by dedicated classes
StickRateBase.
- sticking_species¶
The name of the sticking species. Needed only for reactions with multiple non-surface reactant species, where the sticking species is ambiguous.
Deprecated since version 2.6: To be deprecated with version 2.6, and removed thereafter. Replaced by property
stickRateBase.sticking_species.
- use_motz_wise_correction¶
Get/Set a boolean indicating whether to use the correction factor developed by Motz & Wise for reactions with high (near-unity) sticking coefficients when converting the sticking coefficient to a rate coefficient.
Deprecated since version 2.6: To be deprecated with version 2.6, and removed thereafter. Replaced by property
stickRateBase.mote_wise_correction.
Reaction Rates¶
ReactionRate¶
- class cantera.ReactionRate¶
Bases:
objectBase class for ReactionRate objects.
ReactionRate objects are used to calculate reaction rates and are associated with a Reaction object.
- from_dict(type cls, data)¶
Create a
ReactionRateobject from a dictionary corresponding to its YAML representation.An example for the creation of a
ReactionRatefrom a dictionary is:rate = ReactionRate.from_dict( {"rate-constant": {"A": 38.7, "b": 2.7, "Ea": 26191840.0}})
- Parameters
data – A dictionary corresponding to the YAML representation.
- from_yaml(type cls, text)¶
Create a
ReactionRateobject from its YAML string representation.An example for the creation of a
ReactionRatefrom a YAML string is:rate = ReactionRate.from_yaml( "rate-constant: {A: 38.7, b: 2.7, Ea: 6260.0 cal/mol}")
Units for
Arequire a unit system with length inmand quantity inkmol(standard Cantera units).- Parameters
text – The YAML reaction rate string.
- input_data¶
Get input data for this reaction rate with its current parameter values.
- type¶
Get the C++ ReactionRate type
ArrheniusRateBase¶
- class cantera.ArrheniusRateBase(input_data)¶
Bases:
ReactionRateBase class collecting commonly used features of Arrhenius-type rate objects. Objects should be instantiated by specialized classes, for example
ArrheniusRate,BlowersMaselRateandTwoTempPlasmaRate.- activation_energy¶
The activation energy
E[J/kmol].
- allow_negative_pre_exponential_factor¶
Get/Set whether the rate coefficient is allowed to have a negative pre-exponential factor.
- pre_exponential_factor¶
The pre-exponential factor
Ain units of m, kmol, and s raised to powers depending on the reaction order.
- temperature_exponent¶
The temperature exponent
b.
ArrheniusRate¶
- class cantera.ArrheniusRate(A, b, Ea)¶
Bases:
ArrheniusRateBaseA reaction rate coefficient which depends on temperature only and follows the modified Arrhenius form:
\[k_f = A T^b \exp(-\tfrac{E_a}{RT})\]where
Ais thepre_exponential_factor,bis thetemperature_exponent, andEais theactivation_energy.
BlowersMaselRate¶
- class cantera.BlowersMaselRate(A, b, Ea, w)¶
Bases:
ArrheniusRateBaseA reaction rate coefficient which depends on temperature and enthalpy change of the reaction follows the Blowers-Masel approximation and modified Arrhenius form described in
ArrheniusRate.- bond_energy¶
Average bond dissociation energy of the bond being formed and broken in the reaction
E[J/kmol].
- delta_enthalpy¶
Enthalpy change of reaction
deltaH[J/kmol]The enthalpy change of reaction is a function of temperature and thus not an independent property. Accordingly, the setter should be only used for testing purposes, as any value will be overwritten by an update of the thermodynamic state.
Warning: this property is an experimental part of the Cantera API and may be changed or removed without notice.
TwoTempPlasmaRate¶
- class cantera.TwoTempPlasmaRate(A, b, Ea_gas, Ea_electron)¶
Bases:
ArrheniusRateBaseA reaction rate coefficient which depends on both gas and electron temperature with the form similar to the modified Arrhenius form. Specifically, the temperature exponent (b) is applied to the electron temperature instead. In addition, the exponential term with activation energy for electron is included.
\[k_f = A T_e^b \exp(-\tfrac{E_{a,g}}{RT}) \exp(\tfrac{E_{a,e}(T_e - T)}{R T T_e})\]where \(A\) is the
pre_exponential_factor, \(b\) is thetemperature_exponent, \(E_{a,g}\) (Ea_gas) is theactivation_energy, and \(E_{a,e}\) (Ea_electron) is theactivation_electron_energy.- activation_electron_energy¶
The activation electron energy \(E_{a,e}\) [J/kmol].
FalloffRate¶
- class cantera.FalloffRate¶
Bases:
ReactionRateBase class for parameterizations used to describe the fall-off in reaction rates due to intermolecular energy transfer. These objects are used by
FalloffReaction. Note thatFalloffRateis a base class for specialized fall-off parameterizations and cannot be instantiated by itself.- allow_negative_pre_exponential_factor¶
Get/Set whether the rate coefficient is allowed to have a negative pre-exponential factor.
- chemically_activated¶
Get whether the object is a chemically-activated reaction rate.
- falloff_coeffs¶
The array of coefficients used to define this falloff function.
- falloff_function(self, double temperature, double conc3b)¶
Evaluate the falloff function based on temperature and third-body concentration.
LindemannRate¶
- class cantera.LindemannRate(low, high, falloff_coeffs)¶
Bases:
FalloffRateThe Lindemann falloff parameterization.
This class implements the simple falloff function \(F(T,P_r) = 1.0\).
TroeRate¶
- class cantera.TroeRate(low, high, falloff_coeffs)¶
Bases:
FalloffRateThe 3- or 4-parameter Troe falloff function.
- Parameters
falloff_coeffs – An array of 3 or 4 parameters: \([a, T^{***}, T^*, T^{**}]\) where the final parameter is optional (with a default value of 0).
SriRate¶
- class cantera.SriRate(low, high, falloff_coeffs)¶
Bases:
FalloffRateThe 3- or 5-parameter SRI falloff function.
- Parameters
falloff_coeffs – An array of 3 or 5 parameters: \([a, b, c, d, e]\) where the last two parameters are optional (with default values of 1 and 0, respectively).
TsangRate¶
- class cantera.TsangRate(low, high, falloff_coeffs)¶
Bases:
FalloffRateThe Tsang falloff parameterization.
PlogRate¶
- class cantera.PlogRate(rates)¶
Bases:
ReactionRateA pressure-dependent reaction rate parameterized by logarithmically interpolating between Arrhenius rate expressions at various pressures.
ChebyshevRate¶
- class cantera.ChebyshevRate(temperature_range, pressure_range, data)¶
Bases:
ReactionRateA pressure-dependent reaction rate parameterized by a bivariate Chebyshev polynomial in temperature and pressure.
- data¶
2D array of Chebyshev coefficients where rows and columns correspond to temperature and pressure dimensions over which the Chebyshev fit is computed.
- n_pressure¶
Number of pressures over which the Chebyshev fit is computed (same as number of columns of
dataproperty).
- n_temperature¶
Number of temperatures over which the Chebyshev fit is computed. (same as number of rows of
dataproperty).
- pressure_range¶
Valid pressure range [Pa] for the Chebyshev fit
- temperature_range¶
Valid temperature range [K] for the Chebyshev fit
CustomRate¶
- class cantera.CustomRate(k)¶
Bases:
ReactionRateA custom rate coefficient which depends on temperature only.
The simplest way to create a
CustomRateobject is to use a lambda function, for example:rr = CustomRate(lambda T: 38.7 * T**2.7 * exp(-3150.15/T))
Warning: this class is an experimental part of the Cantera API and may be changed or removed without notice.
- set_rate_function(self, k)¶
Set the function describing a custom reaction rate:
rr = CustomRate() rr.set_rate_function(lambda T: 38.7 * T**2.7 * exp(-3150.15/T))
InterfaceRateBase¶
- class cantera.InterfaceRateBase¶
Bases:
ArrheniusRateBaseBase class collecting commonly used features of Arrhenius-type rate objects that include coverage dependencies.
- beta¶
Return the charge transfer beta parameter
- coverage_dependencies¶
Get/set a dictionary containing adjustments to the Arrhenius rate expression dependent on surface species coverages. The keys of the dictionary are species names, and the values are dictionaries specifying the three coverage parameters
a,mandEwhich are the modifiers for the pre-exponential factor [m, kmol, s units], the temperature exponent [nondimensional], and the activation energy [J/kmol], respectively.
- set_species(self, species)¶
Set association with an ordered list of all species associated with an
InterfaceKineticsobject.
- site_density¶
Site density [kmol/m^2]
The site density is not an independent property, as it is set by an associated
InterfaceKineticsobject. Accordingly, the setter should be only used for testing purposes, as the value will be overwritten by an update of the thermodynamic state.Warning: this property is an experimental part of the Cantera API and may be changed or removed without notice.
- uses_electrochemistry¶
Return boolean flag indicating whether rate involves a charge transfer.
InterfaceArrheniusRate¶
- class cantera.InterfaceArrheniusRate(A, b, Ea)¶
Bases:
InterfaceRateBaseA reaction rate coefficient which depends on temperature and interface coverage
InterfaceBlowersMaselRate¶
- class cantera.InterfaceBlowersMaselRate(A, b, Ea0, w)¶
Bases:
InterfaceRateBaseA reaction rate coefficient which depends on temperature and enthalpy change of the reaction follows the Blowers-Masel approximation and modified Arrhenius form described in
ArrheniusRate.- bond_energy¶
Average bond dissociation energy of the bond being formed and broken in the reaction
E[J/kmol].
- delta_enthalpy¶
Enthalpy change of reaction
deltaH[J/kmol]The enthalpy change of reaction is a function of temperature and thus not an independent property. Accordingly, the setter should be only used for testing purposes, as any value will be overwritten by an update of the thermodynamic state.
Warning: this property is an experimental part of the Cantera API and may be changed or removed without notice.
StickRateBase¶
- class cantera.StickRateBase¶
Bases:
InterfaceRateBaseBase class collecting commonly used features of Arrhenius-type sticking rate objects that include coverage dependencies.
- motz_wise_correction¶
Get/Set a boolean indicating whether to use the correction factor developed by Motz & Wise for reactions with high (near-unity) sticking coefficients when converting the sticking coefficient to a rate coefficient.
- sticking_order¶
The exponent applied to site density (sticking order).
The sticking order is not an independent property and is detected automatically by Cantera. Accordingly, the setter should be only used for testing purposes.
Warning: this property is an experimental part of the Cantera API and may be changed or removed without notice.
- sticking_species¶
The name of the sticking species. Needed only for reactions with multiple non-surface reactant species, where the sticking species is ambiguous.
- sticking_weight¶
The molecular weight of the sticking species.
The sticking weight is not an independent property and is detected automatically by Cantera. Accordingly, the setter should be only used for testing purposes.
Warning: this property is an experimental part of the Cantera API and may be changed or removed without notice.
StickingArrheniusRate¶
- class cantera.StickingArrheniusRate(A, b, Ea)¶
Bases:
StickRateBaseA surface sticking rate expression based on the Arrhenius parameterization
StickingBlowersMaselRate¶
- class cantera.StickingBlowersMaselRate(A, b, Ea0, w)¶
Bases:
StickRateBaseA surface sticking rate expression based on the Blowers-Masel parameterization
- bond_energy¶
Average bond dissociation energy of the bond being formed and broken in the reaction
E[J/kmol].
- delta_enthalpy¶
Enthalpy change of reaction
deltaH[J/kmol]The enthalpy change of reaction is a function of temperature and thus not an independent property. Accordingly, the setter should be only used for testing purposes, as any value will be overwritten by an update of the thermodynamic state.
Warning: this property is an experimental part of the Cantera API and may be changed or removed without notice.
Auxiliary Reaction Data (legacy only)¶
Arrhenius¶
- class cantera.Arrhenius(A, b, E)¶
Bases:
objectA reaction rate coefficient which depends on temperature only and follows the modified Arrhenius form:
\[k_f = A T^b \exp(-\tfrac{E}{RT})\]where
Ais thepre_exponential_factor,bis thetemperature_exponent, andEis theactivation_energy.- activation_energy¶
The activation energy
E[J/kmol].
- pre_exponential_factor¶
The pre-exponential factor
Ain units of m, kmol, and s raised to powers depending on the reaction order.
- temperature_exponent¶
The temperature exponent
b.
Falloff¶
- class cantera.Falloff(params=(), init=True)¶
Bases:
objectA parameterization used to describe the fall-off in reaction rate constants due to intermolecular energy transfer. These functions are used by reactions defined using the
FalloffReactionandChemicallyActivatedReactionclasses.This base class implements the simple falloff function \(F(T,P_r) = 1.0\).
- Parameters
params – Not used for the “simple” falloff parameterization.
init – Used internally when wrapping FalloffRate objects returned from C++.
Deprecated since version 2.6: To be removed after Cantera 2.6. Capabilities merged into the
LindemannRateclass.- parameters¶
The array of parameters used to define this falloff function.
- type¶
A string defining the type of the falloff parameterization
TroeFalloff¶
- class cantera.TroeFalloff(params=(), init=True)¶
Bases:
FalloffThe 3- or 4-parameter Troe falloff function.
- Parameters
params – An array of 3 or 4 parameters: \([a, T^{***}, T^*, T^{**}]\) where the final parameter is optional (with a default value of 0).
Deprecated since version 2.6: To be removed after Cantera 2.6. Capabilities merged into the
TroeRateclass.
SriFalloff¶
- class cantera.SriFalloff(params=(), init=True)¶
Bases:
FalloffThe 3- or 5-parameter SRI falloff function.
- Parameters
params – An array of 3 or 5 parameters: \([a, b, c, d, e]\) where the last two parameters are optional (with default values of 1 and 0, respectively).
Deprecated since version 2.6: To be removed after Cantera 2.6. Capabilities merged into the
SriRateclass.
Reaction Path Analysis¶
ReactionPathDiagram¶
- class cantera.ReactionPathDiagram(Kinetics kin, str element)¶
Bases:
objectReactionPathDiagram(Kinetics kin, unicode element)
Create a reaction path diagram for the fluxes of the element
elementaccording the the net reaction rates determined by theKineticsobjectkin.- add(self, ReactionPathDiagram other)¶
Add fluxes from
otherto this diagram
- arrow_width¶
Get/Set the arrow width. If < 0, then scale with flux value.
- bold_color¶
Get/Set the color for bold lines
- bold_threshold¶
Get/Set the minimum relative flux for bold lines
- build(self, verbose=False)¶
Build the reaction path diagram. Called automatically by methods which return representations of the diagram, for example write_dot().
- dashed_color¶
Get/Set the color for dashed lines
- display_only(self, int k)¶
Include only species and fluxes that are directly connected to the species with index
k. Set to -1 to include all species.
- dot_options¶
Get/Set options for the ‘dot’ program
- flow_type¶
Get/Set the way flows are drawn. Either ‘NetFlow’ or ‘OneWayFlow’
- font¶
Get/Set the name of the font used
- get_data(self)¶
Get a (roughly) human-readable representation of the reaction path diagram.
- get_dot(self)¶
Return a string containing the reaction path diagram formatted for use by Graphviz’s ‘dot’ program.
- label_threshold¶
Get/Set the minimum relative flux for labels
- log¶
Logging messages generated while building the reaction path diagram
- normal_color¶
Get/Set the color for normal-weight lines
- normal_threshold¶
Get/Set the maximum relative flux for dashed lines
- scale¶
Get/Set the scaling factor for the fluxes. Set to -1 to normalize by the maximum net flux.
- show_details¶
Get/Set whether to show the details of which reactions contribute to the flux.
- threshold¶
Get/Set the threshold for the minimum flux relative value that will be plotted.
- title¶
Get/Set the diagram title
- write_dot(self, filename)¶
Write the reaction path diagram formatted for use by Graphviz’s ‘dot’ program to the file named
filename.
