PDSS.h

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/**
 *  @file PDSS.h
 *    Declarations for the virtual base class PDSS (pressure dependent standard state)
 *    which handles calculations for a single species in a phase
 *    (see \ref pdssthermo and class \link Cantera::PDSS PDSS\endlink).
 */
/*
 * Copyright (2006) Sandia Corporation. Under the terms of
 * Contract DE-AC04-94AL85000 with Sandia Corporation, the
 * U.S. Government retains certain rights in this software.
 */
#ifndef CT_PDSS_H
#define CT_PDSS_H
#include "cantera/base/ct_defs.h"
#include "mix_defs.h"

namespace Cantera
{
/**
 * @defgroup pdssthermo Species Standard-State Thermodynamic Properties
 *
 *   In this module we describe %Cantera's treatment of
 *   pressure dependent standard states
 *   (PDSS) objects. These are objects that calculate the standard
 *   state of a single species that depends on both temperature
 *   and pressure.
 *
 *   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 (i.e., 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.
 *
 *   Class PDSS is the base class
 *   for a family of classes that compute properties of a single
 *   species in a phase at its standard states, for a range of temperatures
 *   and pressures.
 *
 *   Phases which use the VPSSMGr class must have their respective
 *   ThermoPhase objects actually be derivatives of the VPStandardState
 *   class. These classes assume that there exists a standard state
 *   for each species in the phase, where the Thermodynamic functions are specified
 *   as a function of temperature and pressure.  Standard state objects for each
 *   species in the phase are all derived from the PDSS virtual base class.
 *
 *  The following classes inherit from PDSS. Each of these classes
 *  handles just one species.
 *
 *   - PDSS_IdealGas
 *      - standardState model = "IdealGas"
 *      - This model assumes that the species in the phase obeys the
 *        ideal gas law for their pressure dependence. The manager
 *        uses a SimpleThermo object to handle the calculation of the
 *        reference state. This object adds the pressure dependencies
 *        to the thermo functions.
 *
 *   - PDSS_ConstVol
 *      - standardState model = "ConstVol"
 *      - This model assumes that the species in the phase obeys the
 *        constant partial molar volume pressure dependence.
 *        The manager uses a SimpleThermo object to handle the
 *        calculation of the reference state. This object adds the
 *        pressure dependencies to these thermo functions.
 *
 *   - PDSS_SSVol
 *      - standardState model = "constant_incompressible" || model == "constant"
 *      - standardState model = "temperature_polynomial"
 *      - standardState model = "density_temperature_polynomial"
 *      - This model assumes that the species in the phase obey a
 *        fairly general equation of state, but one that separates out
 *        the calculation of the standard state density and/or volume.
 *        Models include a cubic polynomial in temperature for either
 *        the standard state volume or the standard state density.
 *        The manager uses a SimpleThermo object to handle the
 *        calculation of the reference state. This object then adds the
 *        pressure dependencies and the volume terms to these thermo functions
 *        to complete the representation.
 *
 *   - PDSS_Water
 *      - standardState model = "Water"
 *      - This model assumes that
 *        Species 0 is assumed to be water, and a real equation
 *        of state is used to model the T, P behavior.
 *        Note, the model assumes that the species is liquid water,
 *        and not steam.
 *
 *   - PDSS_HKFT
 *      - standardState model = "HKFT"
 *      - This model assumes that the species follows the
 *        HKFT pressure dependent equation of state
 *
 *  The choice of which VPSSMGr object to be used is either implicitly made by
 *  Cantera by querying the XML data file for compatibility or it may
 *  be explicitly requested in the XML file.
 *
 *  Normally the PDSS object is not called directly. Instead the VPSSMgr
 *  object manages the calls to the PDSS object for the entire set of species
 *  that comprise a phase. Additionally, sometimes the VPSSMgr object will not
 *  call the PDSS object at all to calculate thermodynamic properties, instead
 *  relying on its own determination/knowledge for how to calculate thermo
 *  quantities quickly given what it knows about the PDSS objects under its
 *  control.
 *
 *  The PDSS objects may or may not utilize the SpeciesThermo reference state
 *  manager class to calculate the reference state thermodynamics functions in
 *  its own calculation. There are some classes, such as PDSS_IdealGas and
 *  PDSS+_ConstVol, which utilize the SpeciesThermo object because the
 *  calculation is very similar to the reference state calculation, while
 *  there are other classes, PDSS_Water and PDSS_HKFT, which don't utilize the
 *  reference state calculation at all, because it wouldn't make sense to. For
 *  example, using the PDSS_Water module, there isn't anything special about
 *  the reference pressure of 1 bar, so the reference state calculation would
 *  represent a duplication of work. Additionally, when evaluating
 *  thermodynamic properties at higher pressures and temperatures, near the
 *  critical point, evaluation of the thermodynamics at a pressure of 1 bar
 *  may lead to situations where the liquid is unstable, i.e., beyond the
 *  spinodal curve leading to potentially wrong evaluation results.
 *
 *  For cases where the PDSS object doesn't use the SpeciesThermo object, a
 *  dummy SpeciesThermoInterpType object is actually installed into the
 *  SpeciesThermo object for that species. This dummy SpeciesThermoInterpType
 *  object is called a STITbyPDSS object. This object satisfies calls to
 *  SpeciesThermo member functions by actually calling the PDSS object at the
 *  reference pressure.
 *
 * @ingroup thermoprops
 */

class XML_Node;
class SpeciesThermo;
class VPStandardStateTP;
class VPSSMgr;

//! Virtual base class for a species with a pressure dependent
//! standard state
/*!
 * Virtual base class for calculation of the
 * pressure dependent standard state for a single species
 *
 * Class PDSS is the base class for a family of classes that compute
 * properties of a set of species in their standard states at a range of
 * temperatures and pressures. The independent variables for this object are
 * temperature and pressure. The class may have a reference to a SpeciesThermo
 * object which handles the calculation of the reference state temperature
 * behavior of a subset of species.
 *
 * This class is analogous to the SpeciesThermoInterpType class, except that
 * the standard state inherently incorporates the pressure dependence.
 *
 * The class operates on a setState temperature and pressure basis.
 * It only recalculates the standard state when the setState functions
 * for temperature and pressure are called.
 *
 * <H3> Thread Safety </H3>
 *
 * These classes are designed such that they are not thread safe when called
 * by themselves. The reason for this is that they sometimes use shared
 * SpeciesThermo resources where they set the states. This condition may be
 * remedied in the future if we get serious about employing multithreaded
 * capabilities by adding mutex locks to the SpeciesThermo resources.
 *
 * However, in many other respects they can be thread safe. They use separate
 * memory and hold intermediate data.
 *
 * @ingroup pdssthermo
 */
class PDSS
{
public:
    //! @name Constructors
    //! @{

    //! Empty Constructor
    PDSS();

    //! Constructor that initializes the object by examining the XML entries
    //! from the ThermoPhase object
    /*!
     *  This function calls the constructPDSS member function.
     *
     *  @param tp        Pointer to the ThermoPhase object pertaining to the phase
     *  @param spindex   Species index of the species in the phase
     */
    PDSS(VPStandardStateTP* tp, size_t spindex);

    //! Copy Constructor
    /*!
     * @param b object to be copied
     */
    PDSS(const PDSS& b);

    //! Assignment operator
    /*!
     * @param b Object to be copied
     */
    PDSS& operator=(const PDSS& b);

    //! Destructor for the phase
    virtual ~PDSS() {}

    //! Duplication routine for objects which inherit from PDSS
    /*!
     * This function can be used to duplicate objects derived from PDSS even
     * if the application only has a pointer to PDSS to work with.
     *
     * @return A pointer to the base PDSS object type
     */
    virtual PDSS* duplMyselfAsPDSS() const;

    //! @}
    //! @name  Utilities
    //! @{

    //! Returns the type of the standard state parameterization
    /*!
     * @return The integer # of the parameterization
     */
    PDSS_enumType reportPDSSType() const;

     //! @}
     //! @name Molar Thermodynamic Properties of the Species Standard State in the Solution
     //! @{

    //! Return the molar enthalpy in units of J kmol-1
    /*!
     * @return the species standard state enthalpy in J kmol-1 at the current
     *     temperature and pressure.
     */
    virtual doublereal enthalpy_mole() const;

    //! Return the standard state molar enthalpy divided by RT
    /*!
     * @return The dimensionless species standard state enthalpy divided at
     *     the current temperature and pressure.
     */
    virtual doublereal enthalpy_RT() const;

    //! Return the molar internal Energy in units of J kmol-1
    /*!
     * @return The species standard state internal Energy in J kmol-1 at the
     *     current temperature and pressure.
     */
    virtual doublereal intEnergy_mole() const;

    //! Return the molar entropy in units of J kmol-1 K-1
    /*!
     * @return The species standard state entropy in J kmol-1 K-1 at the
     *     current temperature and pressure.
     */
    virtual doublereal entropy_mole() const;

    //! Return the standard state entropy divided by RT
    /*!
     * @return The species standard state entropy divided by RT at the current
     *     temperature and pressure.
     */
    virtual doublereal entropy_R() const;

    //! Return the molar Gibbs free energy in units of J kmol-1
    /*!
     * @return The species standard state Gibbs free energy in J kmol-1 at the
     * current temperature and pressure.
     */
    virtual doublereal gibbs_mole() const;

    //! Return the molar Gibbs free energy divided by RT
    /*!
     * @return The species standard state Gibbs free energy divided by RT at
     *     the current temperature and pressure.
     */
    virtual doublereal gibbs_RT() const;

    //! Return the molar const pressure heat capacity in units of J kmol-1 K-1
    /*!
     * @return The species standard state Cp in J kmol-1 K-1 at the current
     *     temperature and pressure.
     */
    virtual doublereal cp_mole() const;

    //! Return the molar const pressure heat capacity divided by RT
    /*!
     * @return The species standard state Cp divided by RT at the current
     *     temperature and pressure.
     */
    virtual doublereal cp_R() const;

    //! Return the molar const volume heat capacity in units of J kmol-1 K-1
    /*!
     * @return The species standard state Cv in J kmol-1 K-1 at the
     * current temperature and pressure.
     */
    virtual doublereal cv_mole() const;

    //! Return the molar volume at standard state
    /*!
     * @return The standard state molar volume at the current temperature and
     *     pressure. Units are m**3 kmol-1.
     */
    virtual doublereal molarVolume() const;

    //! Return the standard state density at standard state
    /*!
     * @return The standard state density at the current temperature and
     *     pressure. units are kg m-3
     */
    virtual doublereal density() const;

    //! Get the difference in the standard state enthalpy
    //! between the current pressure and the reference pressure, p0.
    virtual doublereal enthalpyDelp_mole() const;

    //! Get the difference in the standard state entropy between
    //! the current pressure and the reference pressure, p0
    virtual doublereal entropyDelp_mole() const;

    //! Get the difference in the standard state Gibbs free energy
    //! between the current pressure and the reference pressure, p0.
    virtual doublereal gibbsDelp_mole() const;

    //! Get the difference in standard state heat capacity
    //! between the current pressure and the reference pressure, p0.
    virtual doublereal cpDelp_mole() const;

    //! @}
    //! @name Properties of the Reference State of the Species in the Solution
    //! @{

    //! Return the reference pressure for this phase.
    doublereal refPressure() const {
        return m_p0;
    }

    //! return the minimum temperature
    doublereal minTemp() const {
        return m_minTemp;
    }

    //! return the minimum temperature
    doublereal maxTemp() const {
        return m_maxTemp;
    }

    //! Return the molar Gibbs free energy divided by RT at reference pressure
    /*!
     * @return The reference state Gibbs free energy at the current
     *     temperature, divided by RT.
     */
    virtual doublereal gibbs_RT_ref() const;

    //! Return the molar enthalpy divided by RT at reference pressure
    /*!
     * @return The species reference state enthalpy at the current
     *     temperature, divided by RT.
     */
    virtual doublereal enthalpy_RT_ref() const;

    //! Return the molar entropy divided by R at reference pressure
    /*!
     * @return The species reference state entropy at the current
     *     temperature, divided by R.
     */
    virtual doublereal entropy_R_ref() const;

    //! Return the molar heat capacity divided by R at reference pressure
    /*!
     * @return The species reference state heat capacity divided by R at the
     * current temperature.
     */
    virtual doublereal cp_R_ref() const;

    //! Return the molar volume at reference pressure
    /*!
     * @return The reference state molar volume. units are m**3 kmol-1.
     */
    virtual doublereal molarVolume_ref() const;

    //! @}
    //!  @name Mechanical Equation of State Properties
    //! @{

    //! Returns the pressure (Pa)
    virtual doublereal pressure() const;

    //! Sets the pressure in the object
    /*!
     * Currently, this sets the pressure in the PDSS object.
     * It is indeterminant what happens to the owning VPStandardStateTP
     * object and to the VPSSMgr object.
     *
     * @param   pres   Pressure to be set (Pascal)
     */
    virtual void setPressure(doublereal pres);

    //! Return the volumetric thermal expansion coefficient. Units: 1/K.
    /*!
     * The thermal expansion coefficient is defined as
     * \f[
     * \beta = \frac{1}{v}\left(\frac{\partial v}{\partial T}\right)_P
     * \f]
     */
    virtual doublereal thermalExpansionCoeff() const;

    //@}
    /// @name  Partial Molar Properties of the Solution
    //@{

    //! Set the internal temperature
    /*!
     * @param temp Temperature (Kelvin)
     */
    virtual void setTemperature(doublereal temp);

    //! Return the current stored temperature
    virtual doublereal temperature() const;

    //! Set the internal temperature and pressure
    /*!
     * @param  temp     Temperature (Kelvin)
     * @param  pres     pressure (Pascals)
     */
    virtual void setState_TP(doublereal temp, doublereal pres);

    //! Set the internal temperature and density
    /*!
     * @param  temp     Temperature (Kelvin)
     * @param  rho      Density (kg m-3)
     */
    virtual void setState_TR(doublereal temp, doublereal rho);

    //! @}
    //! @name  Miscellaneous properties of the standard state
    //! @{

    //! critical temperature
    virtual doublereal critTemperature() const;

    //! critical pressure
    virtual doublereal critPressure() const;

    //! critical density
    virtual doublereal critDensity() const;

    //! saturation pressure
    /*!
     *  @param T Temperature (Kelvin)
     */
    virtual doublereal satPressure(doublereal T);

    //! Return the molecular weight of the species
    //! in units of kg kmol-1
    doublereal molecularWeight() const;

    //! Set the molecular weight of the species
    /*!
     * @param mw Molecular Weight in kg kmol-1
     */
    void setMolecularWeight(doublereal mw);

    //! @}
    //! @name Initialization of the Object
    //! @{

    //! Initialization routine for all of the shallow pointers
    /*!
     *  This is a cascading call, where each level should call the
     *  the parent level.
     *
     *  The initThermo() routines get called before the initThermoXML() routines
     *  from the constructPDSSXML() routine.
     *
     *  Calls initPtrs();
     */
    virtual void initThermo();

    //! Initialization routine for the PDSS object based on the phaseNode
    /*!
     *  This is a cascading call, where each level should call the
     *  the parent level.
     *
     * @param phaseNode  Reference to the phase Information for the phase
     *                   that owns this species.
     *
     * @param id         Optional parameter identifying the name of the
     *                   phase. If none is given, the first XML
     *                   phase element will be used.
     */
    virtual void initThermoXML(const XML_Node& phaseNode, const std::string& id);

    //! This utility function reports back the type of parameterization and
    //! all of the parameters for the species, index.
    /*!
     * @param kindex     Species index
     * @param type      Integer type of the standard type
     * @param c         Vector of coefficients used to set the
     *                  parameters for the standard state.
     * @param minTemp   output - Minimum temperature
     * @param maxTemp   output - Maximum temperature
     * @param refPressure output - reference pressure (Pa).
     */
    virtual void reportParams(size_t& kindex, int& type, doublereal* const c,
                              doublereal& minTemp, doublereal& maxTemp,
                              doublereal& refPressure) const;

private:
    //! Initialize all of the internal shallow pointers that can be initialized
    /*!
     * This routine isn't virtual. It's only applicable for the current class
     */
    void initPtrs();

public:
    //! Initialize or Reinitialize all shallow pointers in the object
    /*!
     *  This command is called to reinitialize all shallow pointers in the
     *  object. It's needed for the duplicator capability
     *
     * @param vptp_ptr       Pointer to the Variable pressure ThermoPhase object
     *                       This object must have already been malloced.
     *
     * @param vpssmgr_ptr    Pointer to the variable pressure standard state
     *                       calculator for this phase
     *
     * @param spthermo_ptr   Pointer to the optional SpeciesThermo object
     *                       that will handle the calculation of the reference
     *                       state thermodynamic coefficients.
     */
    virtual void initAllPtrs(VPStandardStateTP* vptp_ptr, VPSSMgr* vpssmgr_ptr,
                             SpeciesThermo* spthermo_ptr);
    //@}

protected:
    //! Enumerated type describing the type of the PDSS object
    PDSS_enumType m_pdssType;

    //! Current temperature used by the PDSS object
    mutable doublereal m_temp;

    //! State of the system - pressure
    mutable doublereal m_pres;

    //! Reference state pressure of the species.
    doublereal m_p0;

    //! Minimum temperature
    doublereal m_minTemp;

    //! Maximum temperature
    doublereal m_maxTemp;

    //! ThermoPhase which this species belongs to.
    /*!
     * Note, in some
     * applications (i.e., mostly testing applications, this may be a null
     * value. Applications should test whether this is null before usage.
     */
    VPStandardStateTP* m_tp;

    //! Pointer to the VPSS manager for this object
    VPSSMgr* m_vpssmgr_ptr;

    /**
     * Molecular Weight of the species
     */
    doublereal m_mw;

    /**
     * Species index in the ThermoPhase corresponding to this species.
     */
    size_t m_spindex;

    //! Pointer to the species thermodynamic property manager.
    /*!
     * This is a copy of the pointer in the ThermoPhase object. Note, this
     * object doesn't own the pointer. If the SpeciesThermo ThermoPhase object
     * doesn't know or doesn't control the calculation, this will be set to
     * zero.
     */
    SpeciesThermo* m_spthermo;

    //!  Reference state enthalpy divided by RT.
    /*!
     * Storage for the thermo properties is provided by VPSSMgr. This object
     * owns a shallow pointer. Calculated at the current value of T and m_p0
     */
    doublereal* m_h0_RT_ptr;

    //!  Reference state heat capacity divided by R.
    /*!
     *  Storage for the thermo properties is provided by VPSSMgr. Calculated
     *  at the current value of T and m_p0
     */
    doublereal* m_cp0_R_ptr;

    //!  Reference state entropy divided by R.
    /*!
     *  Storage for the thermo properties is provided by VPSSMgr. Calculated
     *  at the current value of T and m_p0
     */
    doublereal* m_s0_R_ptr;

    //!  Reference state Gibbs free energy divided by RT.
    /*!
     *  Calculated at the current value of T and m_p0
     */
    doublereal* m_g0_RT_ptr;

    //!  Reference state molar volume (m3 kg-1)
    /*!
     *  Storage for the thermo properties is provided by VPSSMgr. Calculated
     *  at the current value of T and m_p0
     */
    doublereal* m_V0_ptr;

    //!  Standard state enthalpy divided by RT.
    /*!
     *  Storage for the thermo properties is provided by VPSSMgr. Calculated
     *  at the current value of T and P.
     */
    doublereal* m_hss_RT_ptr;

    //!  Standard state heat capacity divided by R.
    /*!
     *  Storage for the thermo properties is provided by VPSSMgr. Calculated
     *  at the current value of T and P.
     */
    doublereal* m_cpss_R_ptr;

    //!  Standard state entropy divided by R.
    /*!
     *  Storage for the thermo properties is provided by VPSSMgr. Calculated
     *  at the current value of T and P.
     */
    doublereal* m_sss_R_ptr;

    //!  Standard state Gibbs free energy divided by RT.
    /*!
     *  Storage for the thermo properties is provided by VPSSMgr. Calculated
     *  at the current value of T and P.
     */
    doublereal* m_gss_RT_ptr;

    //!  Standard State molar volume (m3 kg-1)
    /*!
     *  Storage for the thermo properties is provided by VPSSMgr. Calculated
     *  at the current value of T and P.
     */
    doublereal* m_Vss_ptr;
};

//! Base class for PDSS classes which compute molar properties directly
class PDSS_Molar : public virtual PDSS
{
public:
    virtual doublereal enthalpy_RT() const;
    virtual doublereal entropy_R() const;
    virtual doublereal gibbs_RT() const;
    virtual doublereal cp_R() const;
};

//! Base class for PDSS classes which compute nondimensional properties directly
class PDSS_Nondimensional : public virtual PDSS
{
public:
    virtual doublereal enthalpy_mole() const;
    virtual doublereal entropy_mole() const;
    virtual doublereal gibbs_mole() const;
    virtual doublereal cp_mole() const;
};

}

#endif