Warning
This documentation is for an old version of Cantera. You can find docs for newer versions here.

Objects Representing Phases¶

Composite Phase Objects
Pure Fluid Phases
Representing Quantities of Phases
Representing Multiple States
Utility Functions

Composite Phase Objects ¶

These classes are composite representations of a substance which has thermodynamic, chemical kinetic, and (optionally) transport properties.

class cantera.Solution(infile='', phaseid='', source=None, thermo=None, species=(), kinetics=None, reactions=(), **kwargs)¶

Bases: cantera._cantera.ThermoPhase, cantera._cantera.Kinetics, cantera._cantera.Transport

A class for chemically-reacting solutions. Instances can be created to represent any type of solution – a mixture of gases, a liquid solution, or a solid solution, for example.

Class Solution derives from classes ThermoPhase, Kinetics, and Transport. It defines no methods of its own, and is provided so that a single object can be used to compute thermodynamic, kinetic, and transport properties of a solution.

To skip initialization of the Transport object, pass the keyword argument transport_model=None to the Solution constructor.

The most common way to instantiate Solution objects is by using a phase definition, species and reactions defined in an input file:

gas = ct.Solution('gri30.cti')

If an input file defines multiple phases, the phase name (in CTI) or id (in XML) can be used to specify the desired phase:

gas = ct.Solution('diamond.cti', 'gas')
diamond = ct.Solution('diamond.cti', 'diamond')

Solution objects can also be constructed using Species and Reaction objects which can themselves either be imported from input files or defined directly in Python:

spec = ct.Species.listFromFile('gri30.cti')
rxns = ct.Reaction.listFromFile('gri30.cti')
gas = ct.Solution(thermo='IdealGas', kinetics='GasKinetics',
                  species=spec, reactions=rxns)

where the thermo and kinetics keyword arguments are strings specifying the thermodynamic and kinetics model, respectively, and species and reactions keyword arguments are lists of Species and Reaction objects, respectively.

For non-trivial uses cases of this functionality, see the examples extract_submechanism.py and mechanism_reduction.py.

In addition, Solution objects can be constructed by passing the text of the CTI or XML phase definition in directly, using the source keyword argument:

cti_def = '''
    ideal_gas(name='gas', elements='O H Ar',
              species='gri30: all',
              reactions='gri30: all',
              options=['skip_undeclared_elements', 'skip_undeclared_species', 'skip_undeclared_third_bodies'],
              initial_state=state(temperature=300, pressure=101325))'''
gas = ct.Solution(source=cti_def)

class cantera.Interface(infile='', phaseid='', phases=(), thermo=None, species=(), kinetics=None, reactions=())¶

Bases: cantera._cantera.InterfacePhase, cantera._cantera.InterfaceKinetics

Two-dimensional interfaces.

Instances of class Interface represent reacting 2D interfaces between bulk 3D phases. Class Interface defines no methods of its own. All of its methods derive from either InterfacePhase or InterfaceKinetics.

To construct an Interface object, adjacent bulk phases which participate in reactions need to be created and then passed in as a list in the phases argument to the constructor:

gas = ct.Solution('diamond.cti', 'gas')
diamond = ct.Solution('diamond.cti', 'diamond')
diamond_surf = ct.Interface('diamond.cti', 'diamond_100', [gas, diamond])

class cantera.DustyGas(infile, phaseid='')¶

Bases: cantera._cantera.ThermoPhase, cantera._cantera.Kinetics, cantera._cantera.DustyGasTransport

A composite class which models a gas in a stationary, solid, porous medium.

The only transport properties computed are the multicomponent diffusion coefficients. The model does not compute viscosity or thermal conductivity.

Pure Fluid Phases ¶

The following convenience functions can be used to create PureFluid objects with the indicated equation of state:

cantera.CarbonDioxide()¶: Create a PureFluid object using the equation of state for carbon dioxide.

cantera.Heptane()¶: Create a PureFluid object using the equation of state for heptane.

cantera.Hfc134a()¶: Create a PureFluid object using the equation of state for HFC-134a.

cantera.Hydrogen()¶: Create a PureFluid object using the equation of state for hydrogen.

cantera.Methane()¶: Create a PureFluid object using the equation of state for methane.

cantera.Nitrogen()¶: Create a PureFluid object using the equation of state for nitrogen.

cantera.Oxygen()¶: Create a PureFluid object using the equation of state for oxygen.

cantera.Water()¶: Create a PureFluid object using the equation of state for water.

Representing Quantities of Phases ¶

class cantera.Quantity(phase, mass=None, moles=None, constant='UV')¶

Bases: object

A class representing a specific quantity of a Solution. In addition to the properties which can be computed for class Solution, class Quantity provides several additional capabilities. A Quantity object is created from a Solution with either the mass or number of moles specified:

>>> gas = ct.Solution('gri30.xml')
>>> gas.TPX = 300, 5e5, 'O2:1.0, N2:3.76'
>>> q1 = ct.Quantity(gas, mass=5) # 5 kg of air

The state of a Quantity can be changed in the same way as a Solution:

>>> q1.TP = 500, 101325

Quantities have properties which provide access to extensive properties:

>>> q1.volume
7.1105094
>>> q1.enthalpy
1032237.84

The size of a Quantity can be changed by setting the mass or number of moles:

>>> q1.moles = 3
>>> q1.mass
86.552196
>>> q1.volume
123.086

or by multiplication:

>>> q1 *= 2
>>> q1.moles
6.0

Finally, Quantities can be added, providing an easy way of calculating the state resulting from mixing two substances:

>>> q1.mass = 5
>>> q2 = ct.Quantity(gas)
>>> q2.TPX = 300, 101325, 'CH4:1.0'
>>> q2.mass = 1
>>> q3 = q1 + q2 # combine at constant UV
>>> q3.T
432.31234
>>> q3.P
97974.9871
>>> q3.mole_fraction_dict()
{'CH4': 0.26452900448117395,
 'N2': 0.5809602821745349,
 'O2': 0.1545107133442912}

If a different property pair should be held constant when combining, this can be specified as follows:

>>> q1.constant = q2.constant = 'HP'
>>> q3 = q1 + q2 # combine at constant HP
>>> q3.T
436.03320
>>> q3.P
101325.0

DP¶: Get/Set density [kg/m^3] and pressure [Pa].

DPX¶: Get/Set density [kg/m^3], pressure [Pa], and mole fractions.

DPY¶: Get/Set density [kg/m^3], pressure [Pa], and mass fractions.

G¶: Get the total Gibbs free energy [J] represented by the Quantity.

H¶: Get the total enthalpy [J] represented by the Quantity.

HP¶: Get/Set enthalpy [J/kg or J/kmol] and pressure [Pa].

HPX¶: Get/Set enthalpy [J/kg or J/kmol], pressure [Pa] and mole fractions.

HPY¶: Get/Set enthalpy [J/kg or J/kmol], pressure [Pa] and mass fractions.

ID¶: The ID of the phase. The default is taken from the CTI/XML input file.

P¶: Pressure [Pa].

P_sat¶: Saturation pressure [Pa] at the current temperature.

S¶: Get the total entropy [J/K] represented by the Quantity.

SP¶: Get/Set entropy [J/kg/K or J/kmol/K] and pressure [Pa].

SPX¶: Get/Set entropy [J/kg/K or J/kmol/K], pressure [Pa], and mole fractions.

SPY¶: Get/Set entropy [J/kg/K or J/kmol/K], pressure [Pa], and mass fractions.

SV¶: Get/Set entropy [J/kg/K or J/kmol/K] and specific volume [m^3/kg or m^3/kmol].

SVX¶: Get/Set entropy [J/kg/K or J/kmol/K], specific volume [m^3/kg or m^3/kmol], and mole fractions.

SVY¶: Get/Set entropy [J/kg/K or J/kmol/K], specific volume [m^3/kg or m^3/kmol], and mass fractions.

T¶: Temperature [K].

TD¶: Get/Set temperature [K] and density [kg/m^3 or kmol/m^3].

TDX¶: Get/Set temperature [K], density [kg/m^3 or kmol/m^3], and mole fractions.

TDY¶: Get/Set temperature [K] and density [kg/m^3 or kmol/m^3], and mass fractions.

TP¶: Get/Set temperature [K] and pressure [Pa].

TPX¶: Get/Set temperature [K], pressure [Pa], and mole fractions.

TPY¶: Get/Set temperature [K], pressure [Pa], and mass fractions.

T_sat¶: Saturation temperature [K] at the current pressure.

U¶: Get the total internal energy [J] represented by the Quantity.

UV¶: Get/Set internal energy [J/kg or J/kmol] and specific volume [m^3/kg or m^3/kmol].

UVX¶: Get/Set internal energy [J/kg or J/kmol], specific volume [m^3/kg or m^3/kmol], and mole fractions.

UVY¶: Get/Set internal energy [J/kg or J/kmol], specific volume [m^3/kg or m^3/kmol], and mass fractions.

V¶: Get the total volume [m^3] represented by the Quantity.

X¶

Get/Set the species mole fractions. Can be set as an array, as a dictionary, or as a string. Always returns an array:

>>> phase.X = [0.1, 0, 0, 0.4, 0, 0, 0, 0, 0.5]
>>> phase.X = {'H2':0.1, 'O2':0.4, 'AR':0.5}
>>> phase.X = 'H2:0.1, O2:0.4, AR:0.5'
>>> phase.X
array([0.1, 0, 0, 0.4, 0, 0, 0, 0, 0.5])

Y¶

Get/Set the species mass fractions. Can be set as an array, as a dictionary, or as a string. Always returns an array:

>>> phase.Y = [0.1, 0, 0, 0.4, 0, 0, 0, 0, 0.5]
>>> phase.Y = {'H2':0.1, 'O2':0.4, 'AR':0.5}
>>> phase.Y = 'H2:0.1, O2:0.4, AR:0.5'
>>> phase.Y
array([0.1, 0, 0, 0.4, 0, 0, 0, 0, 0.5])

add_reaction¶: Add a new reaction to this phase.

add_species¶: Add a new species to this phase. Missing elements will be added automatically.

atomic_weight¶: Atomic weight [kg/kmol] of element m

atomic_weights¶: Array of atomic weight [kg/kmol] for each element in the mixture.

basis¶: Determines whether intensive thermodynamic properties are treated on a mass (per kg) or molar (per kmol) basis. This affects the values returned by the properties h, u, s, g, v, density, cv, and cp, as well as the values used with the state-setting properties such as HPX and UV.

binary_diff_coeffs¶: Binary diffusion coefficients [m^2/s].

chemical_potentials¶: Array of species chemical potentials [J/kmol].

concentrations¶: Get/Set the species concentrations [kmol/m^3].

cp¶: Heat capacity at constant pressure [J/kg/K or J/kmol/K] depending on basis.

cp_mass¶: Specific heat capacity at constant pressure [J/kg/K].

cp_mole¶: Molar heat capacity at constant pressure [J/kmol/K].

creation_rates¶: Creation rates for each species. [kmol/m^3/s] for bulk phases or [kmol/m^2/s] for surface phases.

critical_density¶: Critical density [kg/m^3 or kmol/m^3] depending on basis.

critical_pressure¶: Critical pressure [Pa].

critical_temperature¶: Critical temperature [K].

cv¶: Heat capacity at constant volume [J/kg/K or J/kmol/K] depending on basis.

cv_mass¶: Specific heat capacity at constant volume [J/kg/K].

cv_mole¶: Molar heat capacity at constant volume [J/kmol/K].

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].

density¶: Density [kg/m^3 or kmol/m^3] depending on basis.

density_mass¶: (Mass) density [kg/m^3].

density_mole¶: Molar density [kmol/m^3].

destruction_rates¶: Destruction rates for each species. [kmol/m^3/s] for bulk phases or [kmol/m^2/s] for surface phases.

electric_potential¶: Get/Set the electric potential [V] for this phase.

electrical_conductivity¶: Electrical conductivity. [S/m].

electrochemical_potentials¶: Array of species electrochemical potentials [J/kmol].

element_index¶: The index of element element, which may be specified as a string or an integer. In the latter case, the index is checked for validity and returned. If no such element is present, an exception is thrown.

element_name¶: Name of the element with index m.

element_names¶: A list of all the element names.

element_potentials¶: Get the array of element potentials. The element potentials are only defined for equilibrium states. This method first sets the composition to a state of equilibrium at constant T and P, then computes the element potentials for this equilibrium state.

elemental_mass_fraction¶

Get the elemental mass fraction \(Z_{\mathrm{mass},m}\) of element \(m\) as defined by:

\[Z_{\mathrm{mass},m} = \sum_k \frac{a_{m,k} M_m}{M_k} Y_k\]

with \(a_{m,k}\) being the number of atoms of element \(m\) in species \(k\), \(M_m\) the atomic weight of element \(m\), \(M_k\) the molecular weight of species \(k\), and \(Y_k\) the mass fraction of species \(k\).

Parameters:	m – Base element, may be specified by name or by index.

>>> phase.elemental_mass_fraction('H')
1.0

elemental_mole_fraction¶

Get the elemental mole fraction \(Z_{\mathrm{mole},m}\) of element \(m\) (the number of atoms of element m divided by the total number of atoms) as defined by:

\[Z_{\mathrm{mole},m} = \frac{\sum_k a_{m,k} X_k} {\sum_k \sum_j a_{j,k} X_k}\]

with \(a_{m,k}\) being the number of atoms of element \(m\) in species \(k\), \(\sum_j\) being a sum over all elements, and \(X_k\) being the mole fraction of species \(k\).

Parameters:	m – Base element, may be specified by name or by index.

>>> phase.elemental_mole_fraction('H')
1.0

enthalpy¶: Get the total enthalpy [J] represented by the Quantity.

enthalpy_mass¶: Specific enthalpy [J/kg].

enthalpy_mole¶: Molar enthalpy [J/kmol].

entropy¶: Get the total entropy [J/K] represented by the Quantity.

entropy_mass¶: Specific entropy [J/kg].

entropy_mole¶: Molar entropy [J/kmol/K].

equilibrate(XY=None, *args, **kwargs)¶: Set the state to equilibrium. By default, the property pair self.constant is held constant. See ThermoPhase.equilibrate.

equilibrium_constants¶: Equilibrium constants in concentration units for all reactions.

forward_rate_constants¶: Forward rate constants for all reactions. Units are a combination of kmol, m^3 and s, that depend on the rate expression for the reaction.

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.

g¶: Gibbs free energy [J/kg or J/kmol] depending on basis.

gibbs¶: Get the total Gibbs free energy [J] represented by the Quantity.

gibbs_mass¶: Specific Gibbs free energy [J/kg].

gibbs_mole¶: Molar Gibbs free energy [J/kmol].

h¶: Enthalpy [J/kg or J/kmol] depending on basis.

int_energy¶: Get the total internal energy [J] represented by the Quantity.

int_energy_mass¶: Specific internal energy [J/kg].

int_energy_mole¶: Molar internal energy [J/kmol].

is_reversible¶: True if reaction i_reaction is reversible.

isothermal_compressibility¶: Isothermal compressibility [1/Pa].

kinetics_species_index¶: The index of species species of phase phase within arrays returned by methods of class Kinetics. If species is a string, the phase argument is unused.

mass_fraction_dict¶

max_temp¶: Maximum temperature for which the thermodynamic data for the phase are valid.

mean_molecular_weight¶: The mean molecular weight (molar mass) [kg/kmol].

min_temp¶: Minimum temperature for which the thermodynamic data for the phase are valid.

mix_diff_coeffs¶: Mixture-averaged diffusion coefficients [m^2/s] relating the mass-averaged diffusive fluxes (with respect to the mass averaged velocity) to gradients in the species mole fractions.

mix_diff_coeffs_mass¶: Mixture-averaged diffusion coefficients [m^2/s] relating the diffusive mass fluxes to gradients in the species mass fractions.

mix_diff_coeffs_mole¶: Mixture-averaged diffusion coefficients [m^2/s] relating the molar diffusive fluxes to gradients in the species mole fractions.

modify_reaction¶: Modify the Reaction with index irxn to have the same rate parameters as rxn. rxn must have the same reactants and products and be of the same type (i.e. ElementaryReaction, FalloffReaction, PlogReaction, etc.) as the existing reaction. This method does not modify the third-body efficiencies, reaction orders, or reversibility of the reaction.

modify_species¶

mole_fraction_dict¶

molecular_weights¶: Array of species molecular weights (molar masses) [kg/kmol].

moles¶: Get/Set the number of moles [kmol] represented by the Quantity.

multi_diff_coeffs¶: Multicomponent diffusion coefficients [m^2/s].

multiplier¶: 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. See set_multiplier.

n_atoms¶

Number of atoms of element element in species species. The element and species may be specified by name or by index.

>>> phase.n_atoms('CH4','H')
4

n_elements¶: Number of elements.

n_phases¶: Number of phases in the reaction mechanism.

n_reactions¶: Number of reactions in the reaction mechanism.

n_selected_species¶: Number of species selected for output (by slicing of Solution object)

n_species¶: Number of species.

n_total_species¶: Total number of species in all phases participating in the kinetics mechanism.

name¶: The name assigned to this phase. The default is taken from the CTI/XML input file.

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_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.

partial_molar_cp¶: Array of species partial molar specific heat capacities at constant pressure [J/kmol/K].

partial_molar_enthalpies¶: Array of species partial molar enthalpies [J/kmol].

partial_molar_entropies¶: Array of species partial molar entropies [J/kmol/K].

partial_molar_int_energies¶: Array of species partial molar internal energies [J/kmol].

partial_molar_volumes¶: Array of species partial molar volumes [m^3/kmol].

phase¶: Get the underlying Solution object, with the state set to match the wrapping Quantity object.

product_stoich_coeff¶: The stoichiometric coefficient of species k_spec as a product in reaction i_reaction.

product_stoich_coeffs¶: The array of product stoichiometric coefficients. Element [k,i] of this array is the product stoichiometric coefficient of species k in reaction i.

products¶: The products portion of the reaction equation

reactant_stoich_coeff¶: The stoichiometric coefficient of species k_spec as a reactant in reaction i_reaction.

reactant_stoich_coeffs¶: The array of reactant stoichiometric coefficients. Element [k,i] of this array is the reactant stoichiometric coefficient of species k in reaction i.

reactants¶: The reactants portion of the reaction equation

reaction¶: Return a Reaction object representing the reaction with index i_reaction.

reaction_equation¶: The equation for the specified reaction. See also reaction_equations.

reaction_equations¶

Returns a list containing the reaction equation for all reactions in the mechanism (if indices is unspecified) or the equations for each reaction in the sequence indices. 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']

Representing Multiple States ¶

class cantera.SolutionArray(phase, shape=(0, ), states=None, extra=None)¶

Bases: object

A class providing a convenient interface for representing many thermodynamic states using the same Solution object and computing properties for that array of states.

SolutionArray can represent both 1D and multi-dimensional arrays of states, with shapes described in the same way as Numpy arrays. All of the states can be set in a single call.

>>> gas = ct.Solution('gri30.cti')
>>> states = ct.SolutionArray(gas, (6, 10))
>>> T = np.linspace(300, 1000, 10) # row vector
>>> P = ct.one_atm * np.linspace(0.1, 5.0, 6)[:,np.newaxis] # column vector
>>> X = 'CH4:1.0, O2:1.0, N2:3.76'
>>> states.TPX = T, P, X

Similar to Numpy arrays, input with fewer non-singleton dimensions than the SolutionArray is ‘broadcast’ to generate input of the appropriate shape. In the above example, the single value for the mole fraction input is applied to each input, while each row has a constant temperature and each column has a constant pressure.

Computed properties are returned as Numpy arrays with the same shape as the array of states, with additional dimensions appended as necessary for non- scalar output (e.g. per-species or per-reaction properties):

>>> h = states.enthalpy_mass
>>> h[i,j] # -> enthalpy at P[i] and T[j]
>>> sk = states.partial_molar_entropies
>>> sk[i,:,k] # -> entropy of species k at P[i] and each temperature
>>> ropnet = states.net_rates_of_progress
>>> ropnet[i,j,n] # -> net reaction rate for reaction n at P[i] and T[j]

In the case of 1D arrays, additional states can be appended one at a time:

>>> states = ct.SolutionArray(gas) # creates an empty SolutionArray
>>> for phi in np.linspace(0.5, 2.0, 20):
...     states.append(T=300, P=ct.one_atm,
...                   X={'CH4': phi, 'O2': 2, 'N2': 2*3.76})
>>> # 'states' now contains 20 elements
>>> states.equilibrate('HP')
>>> states.T # -> adiabatic flame temperature at various equivalence ratios

SolutionArray objects can also be ‘sliced’ like Numpy arrays, which can be used both for accessing and setting properties:

>>> states = ct.SolutionArray(gas, (6, 10))
>>> states[0].TP = 400, None # set the temperature of the first row to 400 K
>>> cp = states[:,1].cp_mass # heat capacity of the second column

If many slices or elements of a property are going to be accessed (i.e. within a loop), it is generally more efficient to compute the property array once and access this directly, rather than repeatedly slicing the SolutionArray object, e.g.:

>>> mu = states.viscosity
>>> for i,j in np.ndindex(mu.shape):
...     # do something with mu[i,j]

Information about a subset of species may also be accessed, using parentheses to specify the species:

>>> states('CH4').Y # -> mass fraction of CH4 in each state
>>> states('H2','O2').partial_molar_cp # -> cp for H2 and O2

Properties and functions which are not dependent on the thermodynamic state act as pass-throughs to the underlying Solution object, and are not converted to arrays:

>>> states.element_names
['O', 'H', 'C', 'N', 'Ar']
>>> s.reaction_equation(10)
'CH4 + O <=> CH3 + OH'

Data represnted by a SolutionArray can be extracted and saved to a CSV file using the write_csv method:

>>> states.write_csv('somefile.csv', cols=('T','P','X','net_rates_of_progress'))

Parameters:	phase – The `Solution` object used to compute the thermodynamic, kinetic, and transport properties shape – A tuple or integer indicating the dimensions of the SolutionArray. If the shape is 1D, the array may be extended using the `append` method. Otherwise, the shape is fixed. states – The initial array of states. Used internally to provide slicing support.

DP¶: Get/Set density [kg/m^3] and pressure [Pa].

DPX¶: Get/Set density [kg/m^3], pressure [Pa], and mole fractions.

DPY¶: Get/Set density [kg/m^3], pressure [Pa], and mass fractions.

HP¶: Get/Set enthalpy [J/kg or J/kmol] and pressure [Pa].

HPX¶: Get/Set enthalpy [J/kg or J/kmol], pressure [Pa] and mole fractions.

HPY¶: Get/Set enthalpy [J/kg or J/kmol], pressure [Pa] and mass fractions.

ID¶: The ID of the phase. The default is taken from the CTI/XML input file.

P¶: Pressure [Pa].

PV¶: Get/Set the pressure [Pa] and specific volume [m^3/kg] of a PureFluid.

PX¶: Get/Set the pressure [Pa] and vapor fraction of a two-phase state.

P_sat¶: Saturation pressure [Pa] at the current temperature.

SH¶: Get/Set the specific entropy [J/kg/K] and the specific enthalpy [J/kg] of a PureFluid.

SP¶: Get/Set entropy [J/kg/K or J/kmol/K] and pressure [Pa].

SPX¶: Get/Set entropy [J/kg/K or J/kmol/K], pressure [Pa], and mole fractions.

SPY¶: Get/Set entropy [J/kg/K or J/kmol/K], pressure [Pa], and mass fractions.

ST¶: Get/Set the entropy [J/kg/K] and temperature [K] of a PureFluid.

SV¶: Get/Set entropy [J/kg/K or J/kmol/K] and specific volume [m^3/kg or m^3/kmol].

SVX¶: Get/Set entropy [J/kg/K or J/kmol/K], specific volume [m^3/kg or m^3/kmol], and mole fractions.

SVY¶: Get/Set entropy [J/kg/K or J/kmol/K], specific volume [m^3/kg or m^3/kmol], and mass fractions.

T¶: Temperature [K].

TD¶: Get/Set temperature [K] and density [kg/m^3 or kmol/m^3].

TDX¶: Get/Set temperature [K], density [kg/m^3 or kmol/m^3], and mole fractions.

TDY¶: Get/Set temperature [K] and density [kg/m^3 or kmol/m^3], and mass fractions.

TH¶: Get/Set the temperature [K] and the specific enthalpy [J/kg] of a PureFluid.

TP¶: Get/Set temperature [K] and pressure [Pa].

TPX¶: Get/Set temperature [K], pressure [Pa], and mole fractions.

TPY¶: Get/Set temperature [K], pressure [Pa], and mass fractions.

TV¶: Get/Set the temperature [K] and specific volume [m^3/kg] of a PureFluid.

TX¶: Get/Set the temperature [K] and vapor fraction of a two-phase state.

T_sat¶: Saturation temperature [K] at the current pressure.

UP¶: Get/Set the specific internal energy [J/kg] and the pressure [Pa] of a PureFluid.

UV¶: Get/Set internal energy [J/kg or J/kmol] and specific volume [m^3/kg or m^3/kmol].

UVX¶: Get/Set internal energy [J/kg or J/kmol], specific volume [m^3/kg or m^3/kmol], and mole fractions.

UVY¶: Get/Set internal energy [J/kg or J/kmol], specific volume [m^3/kg or m^3/kmol], and mass fractions.

VH¶: Get/Set the specfic volume [m^3/kg] and the specific enthalpy [J/kg] of a PureFluid.

X¶

Get/Set the species mole fractions. Can be set as an array, as a dictionary, or as a string. Always returns an array:

>>> phase.X = [0.1, 0, 0, 0.4, 0, 0, 0, 0, 0.5]
>>> phase.X = {'H2':0.1, 'O2':0.4, 'AR':0.5}
>>> phase.X = 'H2:0.1, O2:0.4, AR:0.5'
>>> phase.X
array([0.1, 0, 0, 0.4, 0, 0, 0, 0, 0.5])

Y¶

Get/Set the species mass fractions. Can be set as an array, as a dictionary, or as a string. Always returns an array:

>>> phase.Y = [0.1, 0, 0, 0.4, 0, 0, 0, 0, 0.5]
>>> phase.Y = {'H2':0.1, 'O2':0.4, 'AR':0.5}
>>> phase.Y = 'H2:0.1, O2:0.4, AR:0.5'
>>> phase.Y
array([0.1, 0, 0, 0.4, 0, 0, 0, 0, 0.5])

append(state=None, **kwargs)¶

Append an element to the array with the specified state. Elements can only be appended in cases where the array of states is one-dimensional.

The state may be specified in one of three ways:

as the array of [temperature, density, mass fractions] which is returned by Solution.state:
```
mystates.append(gas.state)
```
as a tuple of three elements that corresponds to any of the full-state setters of Solution, e.g. TPY or HPX:
```
mystates.append(TPX=(300, 101325, 'O2:1.0, N2:3.76'))
```
as separate keywords for each of the elements corresponding to one of the full-state setters:
```
mystates.append(T=300, P=101325, X={'O2':1.0, 'N2':3.76})
```

atomic_weight¶: Atomic weight [kg/kmol] of element m

atomic_weights¶: Array of atomic weight [kg/kmol] for each element in the mixture.

basis¶: Determines whether intensive thermodynamic properties are treated on a mass (per kg) or molar (per kmol) basis. This affects the values returned by the properties h, u, s, g, v, density, cv, and cp, as well as the values used with the state-setting properties such as HPX and UV.

binary_diff_coeffs¶: Binary diffusion coefficients [m^2/s].

chemical_potentials¶: Array of species chemical potentials [J/kmol].

collect_data(cols=('extra', 'T', 'density', 'Y'), threshold=0, species='Y')¶

Returns the data specified by cols in a single 2D Numpy array, along with a list of column labels.

Parameters:

cols – A list of any properties of the solution that are scalars or which have a value for each species or reaction. If species names are specified, then either the mass or mole fraction of that species will be taken, depending on the value of species. cols may also include any arrays which were specified as ‘extra’ variables when defining the SolutionArray object. The special value ‘extra’ can be used to include all ‘extra’ variables.
threshold – Relative tolerance for including a particular column. The tolerance is applied by comparing the maximum absolute value for a particular column to the maximum absolute value in all columns for the same variable (e.g. mass fraction).
species – Specifies whether to use mass (‘Y’) or mole (‘X’) fractions for individual species specified in ‘cols’

concentrations¶: Get/Set the species concentrations [kmol/m^3].

coverages¶: Get/Set the fraction of sites covered by each species.

cp¶: Heat capacity at constant pressure [J/kg/K or J/kmol/K] depending on basis.

cp_mass¶: Specific heat capacity at constant pressure [J/kg/K].

cp_mole¶: Molar heat capacity at constant pressure [J/kmol/K].

creation_rates¶: Creation rates for each species. [kmol/m^3/s] for bulk phases or [kmol/m^2/s] for surface phases.

critical_density¶: Critical density [kg/m^3 or kmol/m^3] depending on basis.

critical_pressure¶: Critical pressure [Pa].

critical_temperature¶: Critical temperature [K].

cv¶: Heat capacity at constant volume [J/kg/K or J/kmol/K] depending on basis.

cv_mass¶: Specific heat capacity at constant volume [J/kg/K].

cv_mole¶: Molar heat capacity at constant volume [J/kmol/K].

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].

density¶: Density [kg/m^3 or kmol/m^3] depending on basis.

density_mass¶: (Mass) density [kg/m^3].

density_mole¶: Molar density [kmol/m^3].

destruction_rates¶: Destruction rates for each species. [kmol/m^3/s] for bulk phases or [kmol/m^2/s] for surface phases.

electric_potential¶: Get/Set the electric potential [V] for this phase.

electrical_conductivity¶: Electrical conductivity. [S/m].

electrochemical_potentials¶: Array of species electrochemical potentials [J/kmol].

element_index¶: The index of element element, which may be specified as a string or an integer. In the latter case, the index is checked for validity and returned. If no such element is present, an exception is thrown.

element_name¶: Name of the element with index m.

element_names¶: A list of all the element names.

elemental_mass_fraction(*args, **kwargs)¶

elemental_mole_fraction(*args, **kwargs)¶

enthalpy_mass¶: Specific enthalpy [J/kg].

enthalpy_mole¶: Molar enthalpy [J/kmol].

entropy_mass¶: Specific entropy [J/kg].

entropy_mole¶: Molar entropy [J/kmol/K].

equilibrate(*args, **kwargs)¶: See ThermoPhase.equilibrate

equilibrium_constants¶: Equilibrium constants in concentration units for all reactions.

forward_rate_constants¶: Forward rate constants for all reactions. Units are a combination of kmol, m^3 and s, that depend on the rate expression for the reaction.

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.

g¶: Gibbs free energy [J/kg or J/kmol] depending on basis.

gibbs_mass¶: Specific Gibbs free energy [J/kg].

gibbs_mole¶: Molar Gibbs free energy [J/kmol].

h¶: Enthalpy [J/kg or J/kmol] depending on basis.

int_energy_mass¶: Specific internal energy [J/kg].

int_energy_mole¶: Molar internal energy [J/kmol].

is_reversible¶: True if reaction i_reaction is reversible.

isothermal_compressibility¶: Isothermal compressibility [1/Pa].

kinetics_species_index¶: The index of species species of phase phase within arrays returned by methods of class Kinetics. If species is a string, the phase argument is unused.

max_temp¶: Maximum temperature for which the thermodynamic data for the phase are valid.

mean_molecular_weight¶: The mean molecular weight (molar mass) [kg/kmol].

min_temp¶: Minimum temperature for which the thermodynamic data for the phase are valid.

mix_diff_coeffs¶: Mixture-averaged diffusion coefficients [m^2/s] relating the mass-averaged diffusive fluxes (with respect to the mass averaged velocity) to gradients in the species mole fractions.

mix_diff_coeffs_mass¶: Mixture-averaged diffusion coefficients [m^2/s] relating the diffusive mass fluxes to gradients in the species mass fractions.

mix_diff_coeffs_mole¶: Mixture-averaged diffusion coefficients [m^2/s] relating the molar diffusive fluxes to gradients in the species mole fractions.

modify_reaction¶: Modify the Reaction with index irxn to have the same rate parameters as rxn. rxn must have the same reactants and products and be of the same type (i.e. ElementaryReaction, FalloffReaction, PlogReaction, etc.) as the existing reaction. This method does not modify the third-body efficiencies, reaction orders, or reversibility of the reaction.

molecular_weights¶: Array of species molecular weights (molar masses) [kg/kmol].

multi_diff_coeffs¶: Multicomponent diffusion coefficients [m^2/s].

multiplier¶: 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. See set_multiplier.

n_atoms¶

Number of atoms of element element in species species. The element and species may be specified by name or by index.

>>> phase.n_atoms('CH4','H')
4

n_elements¶: Number of elements.

n_phases¶: Number of phases in the reaction mechanism.

n_reactions¶: Number of reactions in the reaction mechanism.

n_species¶: Number of species.

n_total_species¶: Total number of species in all phases participating in the kinetics mechanism.

name¶: The name assigned to this phase. The default is taken from the CTI/XML input file.

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_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.

partial_molar_cp¶: Array of species partial molar specific heat capacities at constant pressure [J/kmol/K].

partial_molar_enthalpies¶: Array of species partial molar enthalpies [J/kmol].

partial_molar_entropies¶: Array of species partial molar entropies [J/kmol/K].

partial_molar_int_energies¶: Array of species partial molar internal energies [J/kmol].

partial_molar_volumes¶: Array of species partial molar volumes [m^3/kmol].

product_stoich_coeff¶: The stoichiometric coefficient of species k_spec as a product in reaction i_reaction.

product_stoich_coeffs¶: The array of product stoichiometric coefficients. Element [k,i] of this array is the product stoichiometric coefficient of species k in reaction i.

products¶: The products portion of the reaction equation

reactant_stoich_coeff¶: The stoichiometric coefficient of species k_spec as a reactant in reaction i_reaction.

reactant_stoich_coeffs¶: The array of reactant stoichiometric coefficients. Element [k,i] of this array is the reactant stoichiometric coefficient of species k in reaction i.

reactants¶: The reactants portion of the reaction equation

reaction¶: Return a Reaction object representing the reaction with index i_reaction.

reaction_equation¶: The equation for the specified reaction. See also reaction_equations.

reaction_equations¶

Returns a list containing the reaction equation for all reactions in the mechanism (if indices is unspecified) or the equations for each reaction in the sequence indices. 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']

Utility Functions ¶

cantera.add_directory(directory)¶: Add a directory to search for Cantera data files.

cantera.get_data_directories()¶: Get a list of the directories Cantera searches for data files.

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Objects Representing Phases¶

Composite Phase Objects ¶

Pure Fluid Phases ¶

Representing Quantities of Phases ¶

Representing Multiple States ¶

Utility Functions ¶

Objects Representing Phases¶

Composite Phase Objects¶

Pure Fluid Phases¶

Representing Quantities of Phases¶

Representing Multiple States¶

Utility Functions¶

Composite Phase Objects ¶

Pure Fluid Phases ¶

Representing Quantities of Phases ¶

Representing Multiple States ¶

Utility Functions ¶