Home Handbook Наситена и прегрята пара IAPWS-IF97 properties of water and steam
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IAPWS-IF97 properties of water and steam
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Thermodynamic and Transport Properties of Water and Steam

Units

Notation Quantity Unit
T Temperature K
p Pressure MPa
h Enthalpy kJ/kg
v Specific volume m³/kg
rho Density kg/m³
s Specific entropy kJ/(kg·°K)
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 Pa·s
pr Prandtl
kappa Kappa
tc Thermal Conductivity W/(m·°K)
st Surface Tension N/m
x Vapour fraction (0-1) -
vx Vapour Volume Fraction (0-1) -

.

Functions

Temperature (T)

Function Parameters Return Description
Tsat_p p T Saturation temperature
Tsat_s s T Saturation temperature
T_ph p, h T Temperture as a function of pressure and enthalpy
T_ps p, s T Temperture as a function of pressure and entropy
T_hs h, s T Temperture as a function of enthalpy and entropy

Pressure (p)

Function Parameters Return Description
psat_T T p Saturation pressure
psat_s s p Saturation pressure
p_hs h, s p Pressure as a function of h and s
p_hrho h, rho p Pressure as a function of h and rho (density). Very unaccurate for solid water region since it's almost incompressible!

Enthalpy (h)

Function Parameters Return Description
hV_p p h Saturated vapour enthalpy
hL_p p h Saturated liquid enthalpy
hV_T T h Saturated vapour enthalpy
hL_T T h Saturated liquid enthalpy
h_pT p, T h Entalpy as a function of pressure and temperature
h_ps p, s h Entalpy as a function of pressure and entropy
h_px p, x h Entalpy as a function of pressure and vapour fraction
h_Tx T, x h Entalpy as a function of temperature and vapour fraction
h_prho p, rho h Entalpy as a function of pressure and density. Observe for low temperatures (liquid) this equation has 2 solutions (Not valid!!)

Specific Volume (v)

Function Parameters Return Description
vV_p p v Saturated vapour volume
vL_p p v Saturated liquid volume
vV_T T v Saturated vapour volume
vL_T T v Saturated liquid volume
v_pT p, T v Specific volume as a function of pressure and temperature
v_ph p, h v Specific volume as a function of pressure and enthalpy
v_ps p, s v Specific volume as a function of pressure and entropy

Density (rho)

Function Parameters Return Description
rhoV_p p rho Saturated vapour density
rhoL_p p rho Saturated liquid density
rhoL_T T rho Saturated vapour density
rhoV_T T rho Saturated liquid density
rho_pT p, T rho Density as a function of pressure and temperature
rho_ph p, h rho Density as a function of pressure and enthalpy
rho_ps p, s rho Density as a function of pressure and entropy

Specific entropy (s)

Function Parameters Return Description
sV_p p s Saturated vapour entropy
sL_p p s Saturated liquid entropy
sV_T T s Saturated vapour entropy
sL_T T s Saturated liquid entropy
s_pT p, T s Specific entropy as a function of pressure and temperature (Returns saturated vapour entalpy if mixture)
s_ph p, h s Specific entropy as a function of pressure and enthalpy

Specific internal energy (u)

Function Parameters Return Description
uV_p p u Saturated vapour internal energy
uL_p p u Saturated liquid internal energy
uV_T T u Saturated vapour internal energy
uL_T T u Saturated liquid internal energy
u_pT p, T u Specific internal energy as a function of pressure and temperature
u_ph p, h u Specific internal energy as a function of pressure and enthalpy
u_ps p, s u Specific internal energy as a function of pressure and entropy

Specific isobaric heat capacity (Cp)

Function Parameters Return Description
CpV_p p Cp Saturated vapour heat capacity
CpL_p p Cp Saturated liquid heat capacity
CpV_T T Cp Saturated vapour heat capacity
CpL_T T Cp Saturated liquid heat capacity
Cp_pT p, T Cp Specific isobaric heat capacity as a function of pressure and temperature
Cp_ph p, h Cp Specific isobaric heat capacity as a function of pressure and enthalpy
Cp_ps p, s Cp Specific isobaric heat capacity as a function of pressure and entropy

Specific isochoric heat capacity (Cv)

Function Parameters Return Description
CvV_p p Cv Saturated vapour isochoric heat capacity
CvL_p p Cv Saturated liquid isochoric heat capacity
CvV_T T Cv Saturated vapour isochoric heat capacity
CvL_T T Cv Saturated liquid isochoric heat capacity
Cv_pT p, T Cv Specific isochoric heat capacity as a function of pressure and temperature
Cv_ph p, h Cv Specific isochoric heat capacity as a function of pressure and enthalpy
Cv_ps p, s Cv Specific isochoric heat capacity as a function of pressure and entropy

Speed of sound

Function Parameters Return Description
wV_p p w Saturated vapour speed of sound
wL_p p w Saturated liquid speed of sound
wV_T T w Saturated vapour speed of sound
wL_T T w Saturated liquid speed of sound
w_pT p, T w Speed of sound as a function of pressure and temperature
w_ph p, h w Speed of sound as a function of pressure and enthalpy
w_ps p, s w Speed of sound as a function of pressure and entropy

Viscosity

Function Parameters Return Description
my_pT p, T my Viscosity as a function of pressure and temperature
my_ph p, h my Viscosity as a function of pressure and enthalpy
my_ps p, s my Viscosity as a function of pressure and entropy

Prandtl

Function Parameters Return Description
Pr_pT p, T

Pr_ph p, h

Kappa

Function Parameters Return Description
Kappa_pT p, T

Kappa_ph p, h

Surface tension

Function Parameters Return Description
st_t T st Surface tension for two phase water/steam as a function of T
st_p p st Surface tension for two phase water/steam as a function of p

Thermal conductivity

Function Parameters Return Description
tcL_p p tc Saturated vapour thermal conductivity
tcV_p p tc Saturated liquid thermal conductivity
tcL_T T tc Saturated vapour thermal conductivity
tcV_T T tc Saturated liquid thermal conductivity
tc_pT p, T tc Thermal conductivity as a function of pressure and temperature
tc_ph p, h tc Thermal conductivity as a function of pressure and enthalpy
tc_hs h, s tc Thermal conductivity as a function of enthalpy and entropy

Vapour fraction

Function Parameters Return Description
x_ph p, h x Vapour fraction as a function of pressure and enthalpy
x_ps p, s x Vapour fraction as a function of pressure and entropy

Vapour Volume Fraction

Function Parameters Return Description
vx_ph p, h vx Vapour volume fraction as a function of pressure and enthalpy
vx_ps p, s vx Vapour volume fraction as a function of pressure and entropy