STEAM – Steam and water properties

Block SymbolLicensing group: STANDARD

Function Description
The STEAM blok can be used to calculate various thermodynamic properties of water and steam, such as enthalpy, entropy, saturation temperature and pressure, density, viscosity, and others. The inputs of the block are typically temperature and pressure, but calculations can be done in the opposite direction, for example, determining the temperature from the enthalpy. The calculations are based on the international standard IAPWS IF-97, details of which can be found at http://www.iapws.org/relguide/IF97-Rev.pdf.

The units for temperature can be set by the tunit parameter, for pressure by the punit parameter. Energy units are in kilojoules [kJ], for example, enthalpy is expressed in kJ/kg, heat capacity in kJ/kg/K, which corresponds to the definitions in IF-97. Other quantities are given in SI units, such as density in kg/m³.

The block function has a name in the format <output property>_<1st input property><2nd input property>, where the properties include:

T - Temperature
p - Pressure
h - Enthalpy [kJ/kg]
v - Specific volume [m³/kg]
rho - Density [kg/m³]
s - Specific entropy
u - Specific internal energy [kJ/kg]
Cp - Specific isobaric heat capacity [kJ/kg/K]
Cv - Specific isochoric heat capacity [kJ/kg/K]
w - Speed of sound [m/s]
my - Viscosity
tc - Thermal Conductivity
st - Surface Tension
x - Vapour fraction
vx - Vapour Volume Fraction

The output property can have attribute:

sat - Saturated value, i.e. for situation when water (liquid) is changed into steam (vapour)
V - Steam (vapour) for saturated conditions
L - Water (liquid) for saturated conditions

Examples

h_pT output is enthalpy for given pressure (1st input) and temperature (2nd input); for example, for pressure 100 kPa and temperature 120 $^{\circ}$ C, the enthalpy is 2716 kJ/kg.
Tsat_p saturated temperature (i.e. boiling temperature) for given pressure (1st input); for example, for pressure 100 kPa, the boiling temperature is 100 $^{\circ}$ C.
hL_p enthalpy of (liquid) water for saturated conditions given by pressure (1st input); for example, at 100 kPa (and temperature 100 $^{\circ}$ C, to be at saturated conditions), the medium can contain any ratio of water and steam, the function (block output) will be the enthalpy for the situation when the medium is water (without steam), i.e. 417 kJ/kg.

This block does not propagate the signal quality. More information can be found in the 1.4 section.

Input

u1	First analog input of the block	Double (F64)
u2	Second analog input of the block	Double (F64)

Parameter

func	Function type $⊙$ 1	Long (I32)
	1 .... Tsat_p 2 .... T_ph 3 .... T_ps 4 .... T_hs 5 .... psat_T 6 .... p_hs 7 .... p_hrho 8 .... hV_p 9 .... hL_p 10 ... hV_T 11 ... hL_T 12 ... h_pT 13 ... h_ps 14 ... h_px 15 ... h_prho 16 ... h_Tx 17 ... vV_p 18 ... vL_p 19 ... vV_T 20 ... vL_T 21 ... v_pT 22 ... v_ph 23 ... v_ps 24 ... sV_p 25 ... sL_p 26 ... sV_T 27 ... sL_T 28 ... s_pT 29 ... s_ph 30 ... CpV_p 31 ... CpL_p 32 ... CpV_T 33 ... CpL_T 34 ... Cp_pT 35 ... Cp_ph 36 ... Cp_ps 37 ... CvV_p 38 ... CvL_p 39 ... CvV_T 40 ... CvL_T 41 ... Cv_pT 42 ... Cv_ph 43 ... Cv_ps 44 ... wV_p 45 ... wL_p 46 ... wV_T 47 ... wL_T 48 ... w_pT 49 ... w_ph 50 ... w_ps 51 ... my_pT 52 ... my_ph 53 ... my_ps 54 ... tcL_p 55 ... tcV_p 56 ... tcL_T 57 ... tcV_T 58 ... tc_pT 59 ... tc_ph 60 ... tc_hs 61 ... st_T 62 ... st_p 63 ... x_ph 64 ... x_ps 65 ... vx_ph 66 ... vx_ps 67 ... rhoV_p 68 ... rhoL_p 69 ... rhoV_T 70 ... rhoL_T 71 ... rho_pT 72 ... rho_ph 73 ... rho_ps 74 ... uV_p 75 ... uL_p 76 ... uV_T 77 ... uL_T 78 ... u_pT 79 ... u_ph 80 ... u_ps
punit	Used unit for pressure $⊙$ 1	Long (I32)
	1 .... MPa 2 .... bar 3 .... kPa
tunit	Used unit for temperature $⊙$ 1	Long (I32)
	1 .... K 2 .... $^{\circ}$ C

Output

y	Analog output of the block	Double (F64)
E	Error indicator	Bool

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