Cantera  3.1.0a1
Species Reference-State Thermodynamic Properties

To compute the thermodynamic properties of multicomponent solutions, it is necessary to know something about the thermodynamic properties of the individual species present in the solution. More...

Collaboration diagram for Species Reference-State Thermodynamic Properties:

Detailed Description

To compute the thermodynamic properties of multicomponent solutions, it is necessary to know something about the thermodynamic properties of the individual species present in the solution.

Exactly what sort of species properties are required depends on the thermodynamic model for the solution. For a gaseous solution (that is, a gas mixture), the species properties required are usually ideal gas properties at the mixture temperature and at a reference pressure (almost always at 1 bar). For other types of solutions, however, it may not be possible to isolate the species in a "pure" state. For example, the thermodynamic properties of, say, Na+ and Cl- in saltwater are not easily determined from data on the properties of solid NaCl, or solid Na metal, or chlorine gas. In this case, the solvation in water is fundamental to the identity of the species, and some other reference state must be used. One common convention for liquid solutions is to use thermodynamic data for the solutes in the limit of infinite dilution within the pure solvent; another convention is to reference all properties to unit molality.

In defining these standard states for species in a phase, we make the following definition. A reference state is a standard state of a species in a phase limited to one particular pressure, the reference pressure. The reference state specifies the dependence of all thermodynamic functions as a function of the temperature, in between a minimum temperature and a maximum temperature. The reference state also specifies the molar volume of the species as a function of temperature. The molar volume is a thermodynamic function. A full standard state does the same thing as a reference state, but specifies the thermodynamics functions at all pressures.

The class SpeciesThermoInterpType is an abstract base class for calculation of thermodynamic functions for a single species in its reference state. The following classes inherit from SpeciesThermoInterpType.

The most important member function for the SpeciesThermoInterpType class is the member function SpeciesThermoInterpType::updatePropertiesTemp(). The function calculates the values of Cp, H, and S for the specific species pertaining to this class.

A key concept for reference states is that there is a maximum and a minimum temperature beyond which the thermodynamic formulation isn't valid. Calls for temperatures outside this range will cause the object to throw a CanteraError.

Classes

class  ConstCpPoly
 A constant-heat capacity species thermodynamic property manager class. More...
 
class  Mu0Poly
 The Mu0Poly class implements an interpolation of the Gibbs free energy based on a piecewise constant heat capacity approximation. More...
 
class  MultiSpeciesThermo
 A species thermodynamic property manager for a phase. More...
 
class  Nasa9Poly1
 The NASA 9 polynomial parameterization for one temperature range. More...
 
class  Nasa9PolyMultiTempRegion
 The NASA 9 polynomial parameterization for a single species encompassing multiple temperature regions. More...
 
class  NasaPoly1
 The NASA polynomial parameterization for one temperature range. More...
 
class  NasaPoly2
 The NASA polynomial parameterization for two temperature ranges. More...
 
class  ShomatePoly
 The Shomate polynomial parameterization for one temperature range for one species. More...
 
class  ShomatePoly2
 The Shomate polynomial parameterization for two temperature ranges for one species. More...
 
class  SpeciesThermoInterpType
 Abstract Base class for the thermodynamic manager for an individual species' reference state. More...