[Thermo] Always use PDSS_ConstVol for constant volume standard state

Remove the redundant (and questionable) implementation of this from the
PDSS_SSVol class. Also fix some values in PDSS_SSVol that were not updated
except in the constant volume case.

include/cantera/thermo/PDSS.h

@@ -67,14 +67,13 @@ namespace Cantera
  *     pressure dependencies to the thermo functions.
  *
  * - PDSS_ConstVol
- *    - standardState model = "ConstVol"
+ *    - standardState model = "ConstVol" or "constant_incompressible"
  *    - 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

include/cantera/thermo/PDSS_SSVol.h

@@ -42,13 +42,6 @@ namespace Cantera
  * The class includes the following models for the representation of the
  * standard state volume:
  *
- * - Constant Volume
- *   - This standard state model is invoked with the keyword "constant_incompressible"
- *     or "constant". The standard state volume is considered constant.
- *     \f[
- *       V^o_k(T,P) = a_0
- *     \f]
- *
  * - Temperature polynomial for the standard state volume
  *   - This standard state model is invoked with the keyword "temperature_polynomial".
  *     The standard state volume is considered a function of temperature only.
@@ -111,29 +104,6 @@ namespace Cantera
  * ## XML Example
  *
  * An example of the specification of a standard state for the LiCl molten salt
- * which employs a constant molar volume expression.
- *
- * @code
- * <speciesData id="species_MoltenSalt">
- * <species name="LiCl(L)">
- *   <atomArray> Li:1 Cl:1 </atomArray>
- *   <standardState  model="constant_incompressible">
- *      <molarVolume> 0.02048004 </molarVolume>
- *   </standardState>
- *   <thermo>
- *     <Shomate Pref="1 bar" Tmax="2000.0" Tmin="700.0">
- *       <floatArray size="7">
- *        73.18025, -9.047232, -0.316390,
- *        0.079587, 0.013594, -417.1314,
- *        157.6711
- *       </floatArray>
- *     </Shomate>
- *   </thermo>
- * </species>
- * </speciesData>
- * @endcode
- *
- * An example of the specification of a standard state for the LiCl molten salt
  * which has a temperature dependent standard state volume.
  *
  * @code
@@ -206,8 +176,6 @@ private:
     //! Types of general formulations for the specification of the standard
     //! state volume
     enum class SSVolume_Model {
-        //! This approximation is for a constant volume
-        constant = 0,
         //! This approximation is for a species with a quadratic polynomial in
         //! temperature
         /*!
@@ -226,12 +194,6 @@ private:
     //! used to calculate the standard state volume of the species
     SSVolume_Model volumeModel_;
 
-    //! Value of the constant molar volume for the species
-    /*!
-     *    m3 / kmol
-     */
-    doublereal m_constMolarVolume;
-
     //! coefficients for the temperature representation
     vector_fp TCoeff_;
 

src/thermo/PDSSFactory.cpp

@@ -26,11 +26,10 @@ PDSSFactory::PDSSFactory()
     m_synonyms["waterPDSS"] = m_synonyms["waterIAPWS"] = "water";
     reg("ions-from-neutral", []() { return new PDSS_IonsFromNeutral(); });
     m_synonyms["IonFromNeutral"] = "ions-from-neutral";
-    reg("constant", []() { return new PDSS_SSVol(); });
+    reg("temperature_polynomial", []() { return new PDSS_SSVol(); });
-    m_synonyms["temperature_polynomial"] = "constant";
+    m_synonyms["temperature-polynomial"] = "temperature_polynomial";
-    m_synonyms["temperature-polynomial"] = "constant";
+    m_synonyms["density_temperature_polynomial"] = "temperature_polynomial";
-    m_synonyms["density_temperature_polynomial"] = "constant";
+    m_synonyms["density-temperature-polynomial"] = "temperature_polynomial";
-    m_synonyms["density-temperature-polynomial"] = "constant";
     reg("HKFT", []() { return new PDSS_HKFT(); });
 }
 

src/thermo/PDSS_SSVol.cpp

@@ -17,8 +17,7 @@ namespace Cantera
 {
 
 PDSS_SSVol::PDSS_SSVol()
-    : volumeModel_(SSVolume_Model::constant)
+    : volumeModel_(SSVolume_Model::tpoly)
-    , m_constMolarVolume(-1.0)
 {
     TCoeff_[0] = 0.0;
     TCoeff_[1] = 0.0;
@@ -35,10 +34,7 @@ void PDSS_SSVol::setParametersFromXML(const XML_Node& speciesNode)
                            "no standardState Node for species " + speciesNode.name());
     }
     std::string model = ss->attrib("model");
-    if (model == "constant_incompressible" || model == "constant") {
+    if (model == "temperature_polynomial") {
-        volumeModel_ = SSVolume_Model::constant;
-        m_constMolarVolume = getFloat(*ss, "molarVolume", "toSI");
-    } else if (model == "temperature_polynomial") {
         volumeModel_ = SSVolume_Model::tpoly;
         size_t num = getFloatArray(*ss, TCoeff_, true, "toSI", "volumeTemperaturePolynomial");
         if (num != 4) {
@@ -54,7 +50,8 @@ void PDSS_SSVol::setParametersFromXML(const XML_Node& speciesNode)
         }
     } else {
         throw CanteraError("PDSS_SSVol::constructPDSSXML",
-                           "standardState model for species isn't constant_incompressible: " + speciesNode.name());
+                           "Unknown standardState model '{}'' for species '{}'",
+                           model, speciesNode.name());
     }
 }
 
@@ -64,8 +61,6 @@ void PDSS_SSVol::initThermo()
     m_minTemp = m_spthermo->minTemp();
     m_maxTemp = m_spthermo->maxTemp();
     m_p0 = m_spthermo->refPressure();
-    m_V0 = m_constMolarVolume;
-    m_Vss = m_constMolarVolume;
 }
 
 doublereal PDSS_SSVol::intEnergy_mole() const
@@ -81,15 +76,15 @@ doublereal PDSS_SSVol::cv_mole() const
 
 void PDSS_SSVol::calcMolarVolume()
 {
-    if (volumeModel_ == SSVolume_Model::constant) {
+    if (volumeModel_ == SSVolume_Model::tpoly) {
-        m_Vss = m_constMolarVolume;
-    } else if (volumeModel_ == SSVolume_Model::tpoly) {
         m_Vss = TCoeff_[0] + m_temp * (TCoeff_[1] + m_temp * (TCoeff_[2] + m_temp * TCoeff_[3]));
+        m_V0 = m_Vss;
         dVdT_ = TCoeff_[1] + 2.0 * m_temp * TCoeff_[2] + 3.0 * m_temp * m_temp * TCoeff_[3];
         d2VdT2_ = 2.0 * TCoeff_[2] + 6.0 * m_temp * TCoeff_[3];
     } else if (volumeModel_ == SSVolume_Model::density_tpoly) {
         doublereal dens = TCoeff_[0] + m_temp * (TCoeff_[1] + m_temp * (TCoeff_[2] + m_temp * TCoeff_[3]));
         m_Vss = m_mw / dens;
+        m_V0 = m_Vss;
         doublereal dens2 = dens * dens;
         doublereal ddensdT = TCoeff_[1] + 2.0 * m_temp * TCoeff_[2] + 3.0 * m_temp * m_temp * TCoeff_[3];
         doublereal d2densdT2 = 2.0 * TCoeff_[2] + 6.0 * m_temp * TCoeff_[3];
@@ -149,12 +144,12 @@ void PDSS_SSVol::setState_TP(doublereal temp, doublereal pres)
 
 void PDSS_SSVol::setState_TR(doublereal temp, doublereal rho)
 {
-    doublereal rhoStored = m_mw / m_constMolarVolume;
+    setTemperature(temp);
+    doublereal rhoStored = m_mw / m_Vss;
     if (fabs(rhoStored - rho) / (rhoStored + rho) > 1.0E-4) {
         throw CanteraError("PDSS_SSVol::setState_TR",
                            "Inconsistent supplied rho");
     }
-    setTemperature(temp);
 }
 
 doublereal PDSS_SSVol::satPressure(doublereal t)