Basic

Base functions as described in IAWPS/IF97

Package Contents

	g1 Gibbs function for region 1: g(p,T)
	g2 Gibbs function for region 2: g(p,T)
	g2metastable Gibbs function for metastable part of region 2: g(p,T)
	f3 Helmholtz function for region 3: f(d,T)
	g5 Base function for region 5: g(p,T)
	gibbs Gibbs function for region 1, 2 or 5: g(p,T,region)
	g1pitau Derivative of g w.r.t. pi and tau
	g2pitau Derivative of g w.r.t. pi and tau
	g5pitau Derivative of g w.r.t. pi and tau
	f3deltatau 1st derivatives of f w.r.t. delta and tau
	tph1 Inverse function for region 1: T(p,h)
	tps1 Inverse function for region 1: T(p,s)
	tph2 Reverse function for region 2: T(p,h)
	tps2a Reverse function for region 2a: T(p,s)
	tps2b Reverse function for region 2b: T(p,s)
	tps2c Reverse function for region 2c: T(p,s)
	tps2 Reverse function for region 2: T(p,s)
	tsat Region 4 saturation temperature as a function of pressure
	dtsatofp Derivative of saturation temperature w.r.t. pressure
	tsat_der Derivative function for tsat
	psat Region 4 saturation pressure as a function of temperature
	dptofT Derivative of pressure w.r.t. temperature along the saturation pressure curve
	psat_der Derivative function for psat
	p1_hs Pressure as a function of enthalpy and entropy in region 1
	h2ab_s Boundary between regions 2a and 2b
	p2a_hs Pressure as a function of enthalpy and entropy in subregion 2a
	p2b_hs Pressure as a function of enthalpy and entropy in subregion 2a
	p2c_hs Pressure as a function of enthalpy and entropy in subregion 2c
	h3ab_p Region 3 a b boundary for pressure/enthalpy
	T3a_ph Region 3 a: inverse function T(p,h)
	T3b_ph Region 3 b: inverse function T(p,h)
	v3a_ph Region 3 a: inverse function v(p,h)
	v3b_ph Region 3 b: inverse function v(p,h)
	T3a_ps Region 3 a: inverse function T(p,s)
	T3b_ps Region 3 b: inverse function T(p,s)
	v3a_ps Region 3 a: inverse function v(p,s)
	v3b_ps Region 3 b: inverse function v(p,s)

Information

This information is part of the Modelica Standard Library maintained by the Modelica Association.

Package description

Package BaseIF97/Basic computes the fundamental functions for the 5 regions of the steam tables as described in the standards document IF97.pdf. The code of these functions has been generated using Mathematica and the add-on packages "Format" and "Optimize" to generate highly efficient, expression-optimized C-code from a symbolic representation of the thermodynamic functions. The C-code has than been transformed into Modelica code. An important feature of this optimization was to simultaneously optimize the functions and the directional derivatives because they share many common subexpressions.

Package contents

Function g1 computes the dimensionless Gibbs function for region 1 and all derivatives up to order 2 w.r.t. pi and tau. Inputs: p and T.
Function g2 computes the dimensionless Gibbs function for region 2 and all derivatives up to order 2 w.r.t. pi and tau. Inputs: p and T.
Function g2metastable computes the dimensionless Gibbs function for metastable vapour (adjacent to region 2 but 2-phase at equilibrium) and all derivatives up to order 2 w.r.t. pi and tau. Inputs: p and T.
Function f3 computes the dimensionless Helmholtz function for region 3 and all derivatives up to order 2 w.r.t. delta and tau. Inputs: d and T.
Function g5computes the dimensionless Gibbs function for region 5 and all derivatives up to order 2 w.r.t. pi and tau. Inputs: p and T.
Function tph1 computes the inverse function T(p,h) in region 1.
Function tph2 computes the inverse function T(p,h) in region 2.
Function tps2a computes the inverse function T(p,s) in region 2a.
Function tps2b computes the inverse function T(p,s) in region 2b.
Function tps2c computes the inverse function T(p,s) in region 2c.
Function tps2 computes the inverse function T(p,s) in region 2.
Function tsat computes the saturation temperature as a function of pressure.
Function dtsatofp computes the derivative of the saturation temperature w.r.t. pressure as a function of pressure.
Function tsat_der computes the Modelica derivative function of tsat.
Function psat computes the saturation pressure as a function of temperature.
Function dptofT computes the derivative of the saturation pressure w.r.t. temperature as a function of temperature.
Function psat_der computes the Modelica derivative function of psat.

Version Info and Revision history

First implemented: July, 2000 by Hubertus Tummescheit

Author: Hubertus Tummescheit,
Modelon AB
Ideon Science Park
SE-22370 Lund, Sweden
email: hubertus@modelon.se

Initial version: July 2000
Documentation added: December 2002

Equation from:

[1] The international Association for the Properties of Water and Steam
Vejle, Denmark
August 2003
Supplementary Release on Backward Equations for the Functions T(p,h), v(p,h) and T(p,s),
v(p,s) for Region 3 of the IAPWS Industrial Formulation 1997 for the Thermodynamic Properties of
Water and Steam