static double RegionOutputBackward(double p, double X, IF97Parameters inkey)
{
// Note that this routine returns only temperature (IF97_T). All other values should be
// calculated from this temperature and the known pressure using forward equations.
// Setup Backward Regions for output
// Make sure input and output keys are valid for Backward formulas
if ((inkey != IF97Parameters.h) && (inkey != IF97Parameters.s))
throw new ArgumentException("Backward Formulas take variable inputs of Enthalpy or Entropy only.");
// Get Saturation Parameters
IF97REGIONS region = RegionDetermination_pX(p, X, inkey);
switch (region)
{
case IF97REGIONS.REGION_1:
if (inkey == IF97Parameters.h)
return B1H.T_pX(p, X);
else
return B1S.T_pX(p, X);
case IF97REGIONS.REGION_2:
if (inkey == IF97Parameters.h)
{
if (p <= 4.0)
return B2aH.T_pX(p, X);
else if (X >= BackwardsRegion.H2b2c_p(p))
return B2bH.T_pX(p, X);
else
return B2cH.T_pX(p, X);
}
else
{
if (p <= 4.0)
return B2aS.T_pX(p, X);
else if (X >= Constants.S2bc)
return B2bS.T_pX(p, X);
else
return B2cS.T_pX(p, X);
};
case IF97REGIONS.REGION_3:
if (inkey == IF97Parameters.h)
{
if (X <= BackwardsRegion.H3ab_p(p))
return B3aH.T_pX(p, X);
else
return B3bH.T_pX(p, X);
}
else
{
if (X <= Constants.Scrit)
return B3aS.T_pX(p, X);
else
return B3bS.T_pX(p, X);
};
case IF97REGIONS.REGION_4: return Tsat97(p);
default: throw new ArgumentOutOfRangeException("Unable to match region");
}
} // Region Output backward
} // Region Output backward
static int BackwardRegion(double p, double X, IF97Parameters inkey)
{
// This routine is for testing purposes only. It returns the
// Region as an integer based on the backward evaluation of either
// (p,h) or (p,s)
// Make sure input and output keys are valid for Backward formulas
if ((inkey != IF97Parameters.h) && (inkey != IF97Parameters.s))
throw new ArgumentException("Backward Formulas take variable inputs of Enthalpy or Entropy only.");
IF97REGIONS region = RegionDetermination_pX(p, X, inkey);
switch (region)
{
case IF97REGIONS.REGION_1: return 1;
case IF97REGIONS.REGION_2: return 2;
case IF97REGIONS.REGION_3: return 3;
case IF97REGIONS.REGION_4: return 4;
default: return 0;
}
}
public static double RegionOutput(IF97Parameters outkey, double T, double p, SatState State)
{
IF97REGIONS region = RegionDetermination_TP(T, p);
switch (region)
{
case IF97REGIONS.REGION_1:
if (State == SatState.VAPOR)
return R2.output(outkey, T, p); // On saturation curve and need the Vapor phase
else
return R1.output(outkey, T, p); // otherwise, use Liquid Region 1
case IF97REGIONS.REGION_2:
if (State == SatState.LIQUID)
return R1.output(outkey, T, p); // On saturation curve and need the Liquid phase
else
return R2.output(outkey, T, p); // otherwise, use Vapor Region 2
case IF97REGIONS.REGION_3:
return Region3.output(outkey, T, p, State);
case IF97REGIONS.REGION_4:
if (State == SatState.VAPOR)
{
return R2.output(outkey, T, p);
}
else if (State == SatState.LIQUID)
{
return R1.output(outkey, T, p);
}
else
{
throw new ArgumentOutOfRangeException("Cannot use Region 4 with T and p as inputs");
}
case IF97REGIONS.REGION_5: return R5.output(outkey, T, p);
}
throw new ArgumentOutOfRangeException("Unable to match region");
}
