NAPROP_s
The procedure NAPROP_s provides the thermodynamic properties of sodium on or under the vapor dome.
Call NAPROP_s(T, x: h, s, v, y2, y4, MW, P_sat)
Inputs:
T: Temperature
x: Quality (mass of vapor/total mass)
Outputs:
h: Enthalpy
s: Entropy
v: Specific volume
y2: Mole fraction of dimer (Na2)
y4: Mole fraction of tetramer (Na4)
MW: Molar mass
P_sat: Saturation pressure
Note that the procedure operates in whatever unit system EES is set to (including molar units). The composition of sodium vapor varies with its state and includes Na, Na2, and Na4 and therefore its molar mass also varies. The mole fraction of Na (the monomer) is y1 = 1 - y2 - y4. The companion function NAPROP_ns provides properties outside of the vapor dome.
The properties come from the NAPROP procedure listed in Sodium-NaK Engineering Handbook, Volume 1.
To get the properties of saturated liquid sodium, set x = 0:
$UnitSystem SI Mass kJ C kPa
T = 1200 [C]
x = 0
Call NAPROP_s(T, x: h, s, v, y2, y4, MW, P_sat)
{Solution: h = 1923 [kJ/kg], s = 4.621 [kJ/kg-K], v = 0.001508 [m^3/kg], y2 = 0, y4 = 0, MW = 22.99 [kg/kmol], P_sat = 953.4 [kPa]}
To get the properties of saturated vapor sodium, set x = 1:
$UnitSystem SI Mass kJ C kPa
T = 1200 [C]
x = 1
Call naprop_s(T, x: h, s, v, y2, y4, MW, P_sat)
{Solution: h = 5478 [kJ/kg], s = 7.035 [kJ/kg-K], v = 0.4678 [m^3/kg], y2 = 0.1594, y4 = 0.01169, MW = 27.46 [kg/kmol], P_sat = 953.4 [kPa]}
To get the properties of sodium with x = 0.5:
$UnitSystem SI Mass kJ C kPa
T = 1200 [C]
x = 0.5
Call naprop_s(T, x: h, s, v, y2, y4, MW, P_sat)
{Solution: h = 3700 [kJ/kg], s = 5.828 [kJ/kg-K], v = 0.2347 [m^3/kg], y2 = 0.07264, y4 = 0.005328, MW = 25.03 [kg/kmol], P_sat = 953.4 [kPa]}