dtofpsOnePhase

Inverse iteration in one phase region (d,T) = f(p,s)

Information

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

This function calculates the density and temperature of R134a from absolute pressure and specific entropy in one-phase region. The function calls the fundamental helmholtz equation of Tillner-Roth (1994) which is requiring density and temperature for input. Thus, a newton iteration is performed to determine density and temperature. The newton iteration stops if the inputs for pressure difference delp and specific entropy difference dels are larger than the actual differences derived from the newton iteration.

Restrictions

The function shall only be used for one-phase inputs since the fundamental equation is not valid for two-phase states. The iteration could fail for liquid states with high pressures.

Syntax

(d, T, error) = dtofpsOnePhase(p, s, delp, dels)

Inputs (4)

p

Type: AbsolutePressure (Pa)

Description: Pressure

s

Type: SpecificEntropy (J/(kg·K))

Description: Specific entropy

delp

Type: AbsolutePressure (Pa)

Description: Absolute iteration accuracy

dels

Type: SpecificEntropy (J/(kg·K))

Description: Absolute iteration accuracy

Outputs (3)

d

Type: Density (kg/m³)

Description: Density

T

Type: Temperature (K)

Description: Temperature

error

Type: Integer

Description: Error flag: trouble if different from 0