phirDT: Second Derivative of the Residual-Gas Part of the Dimensionless Helmholtz Energy Equation
with respect to Density and Temperature, Function of Temperature and Density
Description
The function phirDT(Temp,D,digits=9) returns the Second Derivative of the
Residual-Gas Part of the Dimensionless Helmholtz Energy Equation with respect to D and Temp,
for given Temp [K] and D [kg/m3].
Usage
phirDT(Temp, D, digits)
Value
The Second Derivative of the Residual-Gas Part of the Dimensionless Helmholtz
Energy Equation with respect to D and Temp: phirTT, and an Error Message
(if an error occur: errorCodes)
Arguments
Temp
Temperature [ K ]
D
Density [ kg m-3 ]
digits
Digits of results (optional)
Details
This function calls a Fortran DLL that solves the Helmholtz Energy Equation.
in accordance with the Revised Release on the IAPWS Formulation 1995 for the
Thermodynamic Properties of Ordinary Water Substance for General and Scientific
Use (June 2014) developed by the International Association for the Properties of
Water and Steam, http://www.iapws.org/relguide/IAPWS-95.html. It is valid
from the triple point to the pressure of 1000 MPa and temperature of 1273.