Cantera  2.0
WaterProps Class Reference

The WaterProps class is used to house several approximation routines for properties of water. More...

#include <WaterProps.h>

Collaboration diagram for WaterProps:
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## Public Member Functions

WaterProps ()
Default constructor.

WaterProps (WaterPropsIAPWS *wptr)
Constructor with pointer to Water PDSS object.

WaterProps (PDSS_Water *wptr)
Constructor with pointer to Water PDSS object.

WaterProps (const WaterProps &b)
Copy Constructor.

virtual ~WaterProps ()
destructor

WaterPropsoperator= (const WaterProps &b)
Assignment operator.

doublereal relEpsilon (doublereal T, doublereal P_pascal, int ifunc=0)
Bradley-Pitzer equation for the dielectric constant of water as a function of temperature and pressure.

doublereal ADebye (doublereal T, doublereal P, int ifunc)
ADebye calculates the value of A_Debye as a function of temperature and pressure according to relations that take into account the temperature and pressure dependence of the water density and dielectric constant.

doublereal satPressure (doublereal T)
Returns the saturation pressure given the temperature.

doublereal density_IAPWS (doublereal T, doublereal P)
Returns the density of water.

doublereal density_IAPWS () const
Returns the density of water.

doublereal coeffThermalExp_IAPWS (doublereal T, doublereal P)
returns the coefficient of thermal expansion

doublereal isothermalCompressibility_IAPWS (doublereal T, doublereal P)
Returns the isothermal compressibility of water.

doublereal viscosityWater () const
Returns the viscosity of water at the current conditions (kg/m/s)

doublereal thermalConductivityWater () const
Returns the thermal conductivity of water at the current conditions (W/m/K)

## Static Public Member Functions

static doublereal density_T (doublereal T, doublereal P, int ifunc)
Simple calculation of water density at atmospheric pressure.

## Protected Attributes

WaterPropsIAPWSm_waterIAPWS
Pointer to the WaterPropsIAPWS object.

bool m_own_sub
true if we own the WaterPropsIAPWS object

## Detailed Description

The WaterProps class is used to house several approximation routines for properties of water.

The class is also a wrapper around the WaterPropsIAPWS class which provides the calculations for the equation of state properties for water.

In particular, this class house routine for the calculation of the dielectric constant of water

Most if not all of the member functions are static.

Definition at line 108 of file WaterProps.h.

## Constructor & Destructor Documentation

 WaterProps ( )

Default constructor.

Definition at line 25 of file WaterProps.cpp.

References WaterProps::m_own_sub, and WaterProps::m_waterIAPWS.

 WaterProps ( WaterPropsIAPWS * wptr )

Constructor with pointer to Water PDSS object.

Parameters
 wptr Pointer to WaterPropsIAPWS object

Definition at line 50 of file WaterProps.cpp.

References WaterProps::m_own_sub, and WaterProps::m_waterIAPWS.

 WaterProps ( PDSS_Water * wptr )

Constructor with pointer to Water PDSS object.

Parameters
 wptr Pointer to water standard state object

Definition at line 37 of file WaterProps.cpp.

References PDSS_Water::getWater(), WaterProps::m_own_sub, and WaterProps::m_waterIAPWS.

 WaterProps ( const WaterProps & b )

Copy Constructor.

Copy constructor.

Parameters
 b Object to be copied

Definition at line 66 of file WaterProps.cpp.

 ~WaterProps ( )
virtual

destructor

Destructor.

Definition at line 76 of file WaterProps.cpp.

References WaterProps::m_own_sub, and WaterProps::m_waterIAPWS.

## Member Function Documentation

 WaterProps & operator= ( const WaterProps & b )

Assignment operator.

Parameters
 b Object to be copied

Definition at line 86 of file WaterProps.cpp.

References WaterProps::m_own_sub, and WaterProps::m_waterIAPWS.

 doublereal density_T ( doublereal T, doublereal P, int ifunc )
static

Simple calculation of water density at atmospheric pressure.

Valid up to boiling point.

static function. This formulation has no dependence on the pressure and shouldn't be used where accuracy is needed.

Parameters
 T temperature in kelvin P Pressure in pascal ifunc changes what's returned
Returns
value returned depends on ifunc value: ifunc = 0 Returns the density in kg/m^3 ifunc = 1 returns the derivative of the density wrt T. ifunc = 2 returns the 2nd derivative of the density wrt T ifunc = 3 returns the derivative of the density wrt P.

Verification: Agrees with the CRC values (6-10) for up to 4 sig digits.

units = returns density in kg m-3.

Definition at line 130 of file WaterProps.cpp.

References Cantera::GasConstant.

 doublereal relEpsilon ( doublereal T, doublereal P_pascal, int ifunc = 0 )

Bradley-Pitzer equation for the dielectric constant of water as a function of temperature and pressure.

Returns the dimensionless relative dielectric constant and its derivatives.

Range of validity: 0 to 350C, 0 to 1 kbar pressure

Parameters
 T temperature (kelvin) P_pascal pressure in pascal ifunc changes what's returned from the function ifunc = 0 return value ifunc = 1 return temperature derivative ifunc = 2 return temperature second derivative ifunc = 3 return pressure first derivative
Returns
Depends on the value of ifunc:
• ifunc = 0 return value
• ifunc = 1 return temperature derivative
• ifunc = 2 return temperature second derivative
• ifunc = 3 return pressure first derivative
Validation: Numerical experiments indicate that this function agrees with the Archer and Wang data in the CRC p. 6-10 to all 4 significant digits shown (0 to 100C).

value at 25C and 1 atm, relEps = 78.38

Returns the dimensionless relative dielectric constant and its derivatives.

ifunc = 0 value ifunc = 1 Temperature derivative ifunc = 2 second temperature derivative ifunc = 3 return pressure first derivative

Range of validity 0 to 350C, 0 to 1 kbar pressure

Parameters
 T temperature (kelvin) P_pascal pressure in pascal ifunc changes what's returned from the function
Returns
Depends on the value of ifunc: ifunc = 0 return value ifunc = 1 return temperature derivative ifunc = 2 return second temperature derivative ifunc = 3 return pressure first derivative

Validation: Numerical experiments indicate that this function agrees with the Archer and Wang data in the CRC p. 6-10 to all 4 significant digits shown (0 to 100C).

value at 25C, relEps = 78.38

Definition at line 216 of file WaterProps.cpp.

 doublereal ADebye ( doublereal T, doublereal P, int ifunc )

ADebye calculates the value of A_Debye as a function of temperature and pressure according to relations that take into account the temperature and pressure dependence of the water density and dielectric constant.

The A_Debye expression appears on the top of the ln actCoeff term in the general Debye-Huckel expression It depends on temperature and pressure. And, therefore, most be recalculated whenever T or P changes. The units returned by this expression are sqrt(kg/gmol).

$A_{Debye} = \frac{1}{8 \pi} \sqrt{\frac{2 N_{Avog} \rho_w}{1000}} {\left(\frac{e^2}{\epsilon k_{boltz} T}\right)}^{\frac{3}{2}}$

Nominal value at 25C and 1atm = 1.172576 sqrt(kg/gmol).

         Based on:
epsilon/epsilon_0 = 78.54 (water at 25C)
T = 298.15 K
B_Debye = 3.28640E9 sqrt(kg/gmol)/m

Parameters
 T Temperature (kelvin) P pressure (pascal) ifunc Changes what's returned from the routine: ifunc = 0 return value ifunc = 1 return temperature derivative ifunc = 2 return temperature second derivative ifunc = 3 return pressure first derivative
Returns
Returns a single doublereal whose meaning depends on ifunc:
• ifunc = 0 return value
• ifunc = 1 return temperature derivative
• ifunc = 2 return temperature second derivative
• ifunc = 3 return pressure first derivative
Verification:

With the epsRelWater value from the Bradley-Pitzer relation, and the water density from the density_IAPWS() function, The A_Debye computed with this function agrees with the Pitzer table p. 99 to 4 significant digits at 25C. and 20C. (Aphi = ADebye/3)

Definition at line 278 of file WaterProps.cpp.

 doublereal satPressure ( doublereal T )

Returns the saturation pressure given the temperature.

Parameters
 T temperature (kelvin)
Returns
returns the saturation pressure (pascal)

Definition at line 400 of file WaterProps.cpp.

References WaterProps::m_waterIAPWS, and WaterPropsIAPWS::psat().

 doublereal density_IAPWS ( doublereal T, doublereal P )

Returns the density of water.

This function sets the internal temperature and pressure of the underlying object at the same time.

Parameters
 T Temperature (kelvin) P pressure (pascal)

Definition at line 414 of file WaterProps.cpp.

References WaterPropsIAPWS::density(), and WaterProps::m_waterIAPWS.

 doublereal density_IAPWS ( ) const

Returns the density of water.

This function uses the internal state of the underlying water object

Definition at line 425 of file WaterProps.cpp.

References WaterPropsIAPWS::density(), and WaterProps::m_waterIAPWS.

 doublereal coeffThermalExp_IAPWS ( doublereal T, doublereal P )

returns the coefficient of thermal expansion

Parameters
 T Temperature (kelvin) P pressure (pascal)

Definition at line 431 of file WaterProps.cpp.

 doublereal isothermalCompressibility_IAPWS ( doublereal T, doublereal P )

Returns the isothermal compressibility of water.

Parameters
 T temperature in kelvin P pressure in pascal

Definition at line 442 of file WaterProps.cpp.

 doublereal viscosityWater ( ) const

Returns the viscosity of water at the current conditions (kg/m/s)

This function calculates the value of the viscosity of pure water at the current T and P.

The formulas used are from the paper J. V. Sengers, J. T. R. Watson, "Improved International Formulations for the Viscosity and Thermal Conductivity of Water Substance", J. Phys. Chem. Ref. Data, 15, 1291 (1986).

The formulation is accurate for all temperatures and pressures, for steam and for water, even near the critical point. Pressures above 500 MPa and temperature above 900 C are suspect.

Definition at line 496 of file WaterProps.cpp.

Referenced by WaterTransport::viscosity().

 doublereal thermalConductivityWater ( ) const

Returns the thermal conductivity of water at the current conditions (W/m/K)

This function calculates the value of the thermal conductivity of water at the current T and P.

The formulas used are from the paper J. V. Sengers, J. T. R. Watson, "Improved International Formulations for the Viscosity and Thermal Conductivity of Water Substance", J. Phys. Chem. Ref. Data, 15, 1291 (1986).

The formulation is accurate for all temperatures and pressures, for steam and for water, even near the critical point. Pressures above 500 MPa and temperature above 900 C are suspect.

Definition at line 576 of file WaterProps.cpp.

Referenced by WaterTransport::thermalConductivity().

## Member Data Documentation

 WaterPropsIAPWS* m_waterIAPWS
protected

Pointer to the WaterPropsIAPWS object.

this pointer points to the water object.

Definition at line 341 of file WaterProps.h.

 bool m_own_sub
protected

true if we own the WaterPropsIAPWS object

Definition at line 344 of file WaterProps.h.

Referenced by WaterProps::operator=(), WaterProps::WaterProps(), and WaterProps::~WaterProps().

The documentation for this class was generated from the following files: