| phirDT {IAPWS95} | R Documentation |
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)
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.
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)
Examples
Temp <- 500.
D <- 838.025
phir_DT <- phirDT(Temp,D)
phir_DT