Contents - Index

NAPROP_ns

The procedure NAPROP_ns provides the thermodynamic properties of sodium outside of the vapor dome (superheated vapor or subcooled liquid)

Call NAPROP_ns(T, P: h, s, v, y2, y4, MW, phase)

Inputs:

T: Temperature 

P: Pressure

Outputs:

h: Enthalpy

s: Entropy

v: Specific volume

y2: Mole fraction of dimer (Na2)

y4: Mole fraction of tetramer (Na4)

MW: Molar mass

Phase: Indicates the phase (-100 = subcooled liquid, +100 = superheated vapor)

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_s provides properties inside the vapor dome.

The properties come from the NAPROP procedure listed in -NaK Engineering Handbook, Volume 1.

To find the saturation pressure for sodium at 1200 [C] use NAPROP_s:

$UnitSystem SI Mass kJ C kPa

T = 1200 [C]

x = 0.5

Call naprop_s(T, x: , , , , , , P_sat)

{Solution: P_sat = 953.4 [kPa]}

To get the properties of subcooled liquid sodium, set the pressure to a higher value than the saturation pressure and call NAPROP_ns:

P_sc=1.5*P_sat

Call naprop_ns(T, P_sc: h_sc, s_sc, v_sc, y2_sc, y4_sc, MW_sc, phase_sc)

{Solution: h_sc = 1923 [kJ/kg], s_sc = 4.621 [kJ/kg-K], v_sc = 0.001508 [m^3/kg], y2_sc = 0, y4_sc = 0, MW_sc = 22.99 [kg/kmol], phase_sc = -100}

To get the properties of superheated vapor sodium, set the pressure to a lower value than the saturation pressure and call NAPROP_ns:

P_sh=0.5*P_sat

Call naprop_ns(T, P_sh: h_sh, s_sh, v_sh, y2_sh, y4_sh, MW_sh, phase_sh)

{Solution: h_sh = 5724 [kJ/kg], s_sh = 7.359 [kJ/kg-K], v_sh = 1.015 [m^3/kg], y2_sh = 0.09465, y4_sh = 0.002061, MW_sh = 25.31 [kg/kmol], phase_sh = +100}