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).
 */

// This file is part of Cantera. See License.txt in the top-level directory or
// at http://www.cantera.org/license.txt for license and copyright information.

#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 MultiSpeciesThermo 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 MultiSpeciesThermo 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 MultiSpeciesThermo object, a
 * dummy SpeciesThermoInterpType object is actually installed into the
 * MultiSpeciesThermo object for that species. This dummy
 * SpeciesThermoInterpType object is called a STITbyPDSS object. This object
 * satisfies calls to MultiSpeciesThermo member functions by actually calling
 * the PDSS object at the reference pressure.
 *
 * @ingroup thermoprops
 */

class XML_Node;
class MultiSpeciesThermo;
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 MultiSpeciesThermo
 * 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.
 *
 * ### Thread Safety
 *
 * 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
 * MultiSpeciesThermo 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 MultiSpeciesThermo 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);

    //! @deprecated Copy constructor to be removed after Cantera 2.3 for all
    //!     classes derived from PDSS.
    PDSS(const PDSS& b);
    //! @deprecated Assignment operator to be removed after Cantera 2.3 for all
    //!     classes derived from PDSS.
    PDSS& operator=(const PDSS& b);
    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
     * @deprecated To be removed after Cantera 2.3 for all classes derived from
     *     PDSS.
     */
    virtual PDSS* duplMyselfAsPDSS() const;

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

    //! Returns the type of the standard state parameterization
    /*!
     * @return The integer # of the parameterization
     * @deprecated To be removed after Cantera 2.3.
     */
    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
     * @param vpssmgr_ptr    Pointer to the variable pressure standard state
     *                       calculator for this phase
     * @param spthermo_ptr   Pointer to the optional MultiSpeciesThermo object
     *                       that will handle the calculation of the reference
     *                       state thermodynamic coefficients.
     * @deprecated To be removed after Cantera 2.3 for all classes derived from
     *     PDSS.
     */
    virtual void initAllPtrs(VPStandardStateTP* vptp_ptr, VPSSMgr* vpssmgr_ptr,
                             MultiSpeciesThermo* spthermo_ptr);
    //@}

protected:
    //! Enumerated type describing the type of the PDSS object
    //! @deprecated To be removed after Cantera 2.3.
    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 MultiSpeciesThermo object
     * doesn't know or doesn't control the calculation, this will be set to
     * zero.
     */
    MultiSpeciesThermo* 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