341 lines
12 KiB
C++
341 lines
12 KiB
C++
/**
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* @file StoichSubstance.h
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* Header file for the StoichSubstance class, which represents a fixed-composition
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* incompressible substance (see \ref thermoprops and
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* class \link Cantera::StoichSubstance StoichSubstance\endlink)
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*/
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// This file is part of Cantera. See License.txt in the top-level directory or
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// at http://www.cantera.org/license.txt for license and copyright information.
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#ifndef CT_STOICHSUBSTANCE_H
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#define CT_STOICHSUBSTANCE_H
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#include "SingleSpeciesTP.h"
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namespace Cantera
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{
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//! Class StoichSubstance represents a stoichiometric (fixed composition)
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//! incompressible substance.
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/*!
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* This class internally changes the independent degree of freedom from density
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* to pressure. This is necessary because the phase is incompressible. It uses a
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* constant volume approximation.
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*
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* ## Specification of Species Standard State Properties
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*
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* This class inherits from SingleSpeciesTP. It is assumed that the reference
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* state thermodynamics may be obtained by a pointer to a populated species
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* thermodynamic property manager class (see ThermoPhase::m_spthermo). How to
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* relate pressure changes to the reference state thermodynamics is resolved at
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* this level.
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*
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* For an incompressible, stoichiometric substance, the molar internal energy is
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* independent of pressure. Since the thermodynamic properties are specified by
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* giving the standard-state enthalpy, the term \f$ P_0 \hat v\f$ is subtracted
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* from the specified molar enthalpy to compute the molar internal energy. The
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* entropy is assumed to be independent of the pressure.
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*
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* The enthalpy function is given by the following relation.
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*
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* \f[
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* h^o_k(T,P) =
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* h^{ref}_k(T) + \tilde v \left( P - P_{ref} \right)
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* \f]
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*
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* For an incompressible, stoichiometric substance, the molar internal energy is
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* independent of pressure. Since the thermodynamic properties are specified by
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* giving the standard-state enthalpy, the term \f$ P_{ref} \tilde v\f$ is
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* subtracted from the specified reference molar enthalpy to compute the molar
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* internal energy.
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*
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* \f[
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* u^o_k(T,P) = h^{ref}_k(T) - P_{ref} \tilde v
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* \f]
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*
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* The standard state heat capacity and entropy are independent of pressure. The
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* standard state Gibbs free energy is obtained from the enthalpy and entropy
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* functions.
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*
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* ## Specification of Solution Thermodynamic Properties
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*
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* All solution properties are obtained from the standard state species
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* functions, since there is only one species in the phase.
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*
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* ## Application within Kinetics Managers
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*
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* The standard concentration is equal to 1.0. This means that the kinetics
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* operator works on an (activities basis). Since this is a stoichiometric
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* substance, this means that the concentration of this phase drops out of
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* kinetics expressions.
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*
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* An example of a reaction using this is a sticking coefficient reaction of a
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* substance in an ideal gas phase on a surface with a bulk phase species in
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* this phase. In this case, the rate of progress for this reaction,
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* \f$ R_s \f$, may be expressed via the following equation:
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* \f[
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* R_s = k_s C_{gas}
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* \f]
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* where the units for \f$ R_s \f$ are kmol m-2 s-1. \f$ C_{gas} \f$ has units
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* of kmol m-3. Therefore, the kinetic rate constant, \f$ k_s \f$, has units of
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* m s-1. Nowhere does the concentration of the bulk phase appear in the rate
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* constant expression, since it's a stoichiometric phase and the activity is
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* always equal to 1.0.
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*
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* ## Instantiation of the Class
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*
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* The constructor for this phase is NOT located in the default ThermoFactory
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* for %Cantera. However, a new StoichSubstance may be created by
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* the following code snippets:
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*
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* @code
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* XML_Node *xm = get_XML_NameID("phase", iFile + "#NaCl(S)", 0);
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* StoichSubstance *solid = new StoichSubstance(*xm);
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* @endcode
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*
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* or by the following call to importPhase():
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*
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* @code
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* XML_Node *xm = get_XML_NameID("phase", iFile + "#NaCl(S)", 0);
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* StoichSubstance solid;
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* importPhase(*xm, &solid);
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* @endcode
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*
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* ## XML Example
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*
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* The phase model name for this is called StoichSubstance. It must be supplied
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* as the model attribute of the thermo XML element entry. Within the phase XML
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* block, the density of the phase must be specified. An example of an XML file
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* this phase is given below.
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*
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* @code
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* <!-- phase NaCl(S) -->
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* <phase dim="3" id="NaCl(S)">
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* <elementArray datasrc="elements.xml">
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* Na Cl
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* </elementArray>
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* <speciesArray datasrc="#species_NaCl(S)"> NaCl(S) </speciesArray>
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* <thermo model="StoichSubstance">
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* <density units="g/cm3">2.165</density>
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* </thermo>
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* <transport model="None"/>
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* <kinetics model="none"/>
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* </phase>
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*
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* <!-- species definitions -->
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* <speciesData id="species_NaCl(S)">
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* <!-- species NaCl(S) -->
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* <species name="NaCl(S)">
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* <atomArray> Na:1 Cl:1 </atomArray>
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* <thermo>
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* <Shomate Pref="1 bar" Tmax="1075.0" Tmin="250.0">
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* <floatArray size="7">
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* 50.72389, 6.672267, -2.517167,
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* 10.15934, -0.200675, -427.2115,
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* 130.3973
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* </floatArray>
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* </Shomate>
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* </thermo>
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* <density units="g/cm3">2.165</density>
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* </species>
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* </speciesData> @endcode
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*
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* The model attribute, "StoichSubstance", on the thermo element
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* identifies the phase as being a StoichSubstance object.
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*
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* @ingroup thermoprops
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*/
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class StoichSubstance : public SingleSpeciesTP
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{
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public:
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//! Default constructor for the StoichSubstance class
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StoichSubstance() {}
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//! Construct and initialize a StoichSubstance ThermoPhase object directly
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//! from an ASCII input file
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/*!
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* @param infile name of the input file
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* @param id name of the phase id in the file.
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* If this is blank, the first phase in the file is used.
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*/
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StoichSubstance(const std::string& infile, const std::string& id = "");
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//! Construct and initialize a StoichSubstance ThermoPhase object directly
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//! from an XML database
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/*!
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* @param phaseRef XML node pointing to a StoichSubstance description
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* @param id Id of the phase.
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*/
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StoichSubstance(XML_Node& phaseRef, const std::string& id = "");
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virtual std::string type() const {
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return "StoichSubstance";
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}
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//! @name Mechanical Equation of State
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//! @{
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//! Report the Pressure. Units: Pa.
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/*!
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* For an incompressible substance, the density is independent of pressure.
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* This method simply returns the stored pressure value.
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*/
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virtual doublereal pressure() const;
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//! Set the pressure at constant temperature. Units: Pa.
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/*!
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* For an incompressible substance, the density is independent of pressure.
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* Therefore, this method only stores the specified pressure value. It does
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* not modify the density.
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*
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* @param p Pressure (units - Pa)
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*/
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virtual void setPressure(doublereal p);
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virtual doublereal isothermalCompressibility() const;
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virtual doublereal thermalExpansionCoeff() const;
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/**
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* @}
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* @name Activities, Standard States, and Activity Concentrations
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*
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* This section is largely handled by parent classes, since there
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* is only one species. Therefore, the activity is equal to one.
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* @{
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*/
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//! This method returns an array of generalized concentrations
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/*!
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* \f$ C^a_k\f$ are defined such that \f$ a_k = C^a_k / C^0_k, \f$ where
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* \f$ C^0_k \f$ is a standard concentration defined below and \f$ a_k \f$
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* are activities used in the thermodynamic functions. These activity (or
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* generalized) concentrations are used by kinetics manager classes to
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* compute the forward and reverse rates of elementary reactions.
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*
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* For a stoichiometric substance, there is only one species, and the
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* generalized concentration is 1.0.
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*
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* @param c Output array of generalized concentrations. The
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* units depend upon the implementation of the
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* reaction rate expressions within the phase.
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*/
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virtual void getActivityConcentrations(doublereal* c) const;
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//! Return the standard concentration for the kth species
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/*!
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* The standard concentration \f$ C^0_k \f$ used to normalize the activity
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* (i.e., generalized) concentration. This phase assumes that the kinetics
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* operator works on an dimensionless basis. Thus, the standard
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* concentration is equal to 1.0.
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*
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* @param k Optional parameter indicating the species. The default
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* is to assume this refers to species 0.
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* @return
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* Returns The standard Concentration as 1.0
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*/
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virtual doublereal standardConcentration(size_t k=0) const;
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virtual doublereal logStandardConc(size_t k=0) const;
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//! Get the array of chemical potentials at unit activity for the species at
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//! their standard states at the current *T* and *P* of the solution.
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/*!
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* For a stoichiometric substance, there is no activity term in the chemical
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* potential expression, and therefore the standard chemical potential and
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* the chemical potential are both equal to the molar Gibbs function.
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*
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* These are the standard state chemical potentials \f$ \mu^0_k(T,P) \f$.
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* The values are evaluated at the current temperature and pressure of the
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* solution
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*
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* @param mu0 Output vector of chemical potentials.
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* Length: m_kk.
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*/
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virtual void getStandardChemPotentials(doublereal* mu0) const;
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//@}
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/// @name Properties of the Standard State of the Species in the Solution
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//@{
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virtual void getEnthalpy_RT(doublereal* hrt) const;
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virtual void getEntropy_R(doublereal* sr) const;
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virtual void getGibbs_RT(doublereal* grt) const;
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virtual void getCp_R(doublereal* cpr) const;
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//! Returns the vector of nondimensional Internal Energies of the standard
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//! state species at the current *T* and *P* of the solution
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/*!
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* For an incompressible, stoichiometric substance, the molar internal
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* energy is independent of pressure. Since the thermodynamic properties
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* are specified by giving the standard-state enthalpy, the term
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* \f$ P_{ref} \hat v\f$ is subtracted from the specified reference molar
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* enthalpy to compute the standard state molar internal energy.
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*
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* @param urt output vector of nondimensional standard state
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* internal energies of the species. Length: m_kk.
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*/
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virtual void getIntEnergy_RT(doublereal* urt) const;
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//@}
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/// @name Thermodynamic Values for the Species Reference States
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//@{
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//! Returns the vector of nondimensional internal Energies of the reference
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//! state at the current temperature of the solution and the reference
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//! pressure for each species.
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/*!
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* @param urt Output vector of nondimensional reference state internal
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* energies of the species. Length: m_kk
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*/
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virtual void getIntEnergy_RT_ref(doublereal* urt) const;
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// @}
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virtual void initThermo();
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virtual void initThermoXML(XML_Node& phaseNode, const std::string& id);
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//! Set the equation of state parameters
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/*!
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* @internal
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*
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* @param n number of parameters
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* @param c array of \a n coefficients
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* c[0] = density of phase [ kg/m3 ]
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*/
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virtual void setParameters(int n, doublereal* const c);
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//! Get the equation of state parameters in a vector
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/*!
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* @internal
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*
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* @param n number of parameters
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* @param c array of \a n coefficients
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*
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* For this phase:
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* - n = 1
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* - c[0] = density of phase [ kg/m3 ]
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*/
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virtual void getParameters(int& n, doublereal* const c) const;
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//! Set equation of state parameter values from XML entries.
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/*!
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* For this phase, the density of the phase is specified in this block.
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*
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* @param eosdata An XML_Node object corresponding to
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* the "thermo" entry for this phase in the input file.
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*
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* eosdata points to the thermo block, and looks like this:
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*
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* @code
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* <phase id="stoichsolid" >
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* <thermo model="StoichSubstance">
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* <density units="g/cm3">3.52</density>
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* </thermo>
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* </phase>
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* @endcode
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*/
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virtual void setParametersFromXML(const XML_Node& eosdata);
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};
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}
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#endif
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