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X Steam
2.6!
Freeware IF97 properties for water and steam. |
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Steam and water
properties based on the "International Association for Properties of
Water and Steam Industrial Formulation 1997 (IAPWS IF-97). A full
implementation of the IF-97 standard that provides very accurate
steam and water properties in ranges from 0-1000 bar and 0-2000°C
for use in process Engineering
Industry . Provided thermodynamic properties are:
|
- Temperature
- Pressure
- Enthalpy
- Specific volume
- Density
- Specific entropy |
- Specific internal energy
- Specific isobaric heat capacity
- Specific isochoric heat capacity
- Speed of sound
- Viscosity
- Vapour fraction |
All properties can be
calculated with the inputs, p and T known, p and h known, h and s
known and some with pressure and density known. X Steam are a full
implementation of the IF-97 formulation for industrial use including
all regions and backward functions for good calculation speed.
The code are speed optimized with pressure and enthalpy as inputs
for dynamic simulations.
The code are avalible in the
following releases:
-
Matlab
(XSteam Steam and water properties for
Matlab)
- Excel (XSteam Steam
and water properties as MS Excel Script)
- Ooo Calc (Open Office, Star Office)
(XSteam Steam andwater properties as
Ooo Script)
-
LabVIEW (XSteam
Steam and Water properties for LabVIEW)
-
Application (XSteam
standalone application by Ken Chan. .exe file.)
- Free Basic (XSteam
freebasic translation of source)
- Dynamic Link Libary
(.dll for use with for example Fortran, LabVIEW or
VC++ etc.)
And the
following unsupported translations:
-
ADA-package
XSteam Steam and Water properties
translated to a ADA package by Skorokhodov Denis. (http://r1.repository.org.ru/water_steam_properties)
-
SCILAB XSteam, Steam and Water
properties for SCILAB developed by Torbjørn Pettersen
Calling syntax
XSteam take 2 or 3 arguments. The first argument must always be the
steam table function you want to use. The other arguments are the inputs
to that function.
• Example: XSteam('h_pt',1,20) Returns the enthalpy of water at 1 bar
and 20 degC
• Example: XSteam('TSat_p',1) Returns the saturation temperature of
water at 1 bar.
For a list of valid Steam Table functions se bellow or XSteam for MS Excel
or the documentation that comes with the download.
Development
See the
development page.
Units and notation
Valid XSteam functions are listed in section 3. The notaions used in
XSteam are listed in the table bellow with the currently implemented.
|
Notation |
Quantity |
Unit |
|
T |
Temperature |
°C |
|
p |
Pressure |
bar |
|
h |
Enthalpy |
kJ/kg |
|
v |
Specific volume |
m3/kg |
|
rho |
Density |
kg/ m3 |
|
s |
Specific entropy
|
kJ/(kg °C) |
|
u |
Specific internal energy
|
kJ/kg |
|
Cp |
Specific isobaric heat
capacity |
kJ/(kg °C) |
|
Cv |
Specific isochoric heat
capacity |
kJ/(kg °C) |
|
w |
Speed of sound |
m/s |
|
my |
Viscosity |
Pa s |
|
tc |
Thermal Conductivity |
W/(m °C) |
|
st |
Surface Tension |
N/m |
|
x |
Vapour fraction (0-1) |
- |
|
vx |
Vapour Volume Fraction (0-1) |
- |
Valid calling functions
Temperature
|
Function |
Out |
|
Tsat_p |
Saturation temperature |
|
T_ph |
Temperture as a function of
pressure and enthalpy |
|
T_ps |
Temperture as a function of
pressure and entropy |
|
T_hs |
Temperture as a function of
enthalpy and entropy |
Pressure
|
Function |
Out |
|
psat_T |
Saturation pressure |
|
p_hs |
Pressure as a function of h
and s. |
|
p_hrho |
Pressure as a function of
enthalpy and density |
Enthalpy
|
Function |
Out |
|
hV_p |
Saturated vapour enthalpy |
|
hL_p |
Saturated liquid enthalpy |
|
hV_T |
Saturated vapour enthalpy |
|
hL_T |
Saturated liquid enthalpy |
|
h_pT |
Entalpy as a function of
pressure and temperature. |
|
h_ps |
Entalpy as a function of
pressure and entropy. |
|
h_px |
Entalpy as a function of
pressure and vapour fraction |
|
h_Tx |
Entalpy as a function of
temperature and vapour fraction |
|
h_prho |
Entalpy as a function of
pressure and density. Observe for low temperatures (liquid)
this equation has 2 solutions. (Not valid!!) |
Specific volume
|
Function |
Out |
|
vV_p |
Saturated vapour volume |
|
vL_p |
Saturated liquid volume |
|
vV_T |
Saturated vapour volume |
|
vL_T |
Saturated liquid volume |
|
v_pT |
Specific volume as a function
of pressure and temperature. |
|
v_ph |
Specific volume as a function
of pressure and enthalpy |
|
v_ps |
Specific volume as a function
of pressure and entropy. |
Density
|
Function |
Out |
|
rhoV_p |
Saturated vapour density |
|
rhoL_p |
Saturated liquid density |
|
rhoV_T |
Saturated vapour density |
|
rhoL_T |
Saturated liquid density |
|
rho_pT |
Density as a function of
pressure and temperature. |
|
rho_ph |
Density as a function of
pressure and enthalpy |
|
rho_ps |
Density as a function of
pressure and entropy. |
Specific entropy
|
Function |
Out |
|
sV_p |
Saturated vapour entropy |
|
sL_p |
Saturated liquid entropy |
|
sV_T |
Saturated vapour entropy |
|
sL_T |
Saturated liquid entropy |
|
s_pT |
Specific entropy as a function
of pressure and temperature (Returns saturated vapour
entalpy if mixture.) |
|
s_ph |
Specific entropy as a function
of pressure and enthalpy |
Specific internal energy
|
Function |
Out |
|
uV_p |
Saturated vapour internal
energy |
|
uL_p |
Saturated liquid internal
energy |
|
uV_T |
Saturated vapour internal
energy |
|
uL_T |
Saturated liquid internal
energy |
|
u_pT |
Specific internal energy as a
function of pressure and temperature. |
|
u_ph |
Specific internal energy as a
function of pressure and enthalpy |
|
u_ps |
Specific internal energy as a
function of pressure and entropy. |
Specific isobaric heat
capacity
|
Function |
Out |
|
CpV_p |
Saturated vapour heat capacity
|
|
CpL_p |
Saturated liquid heat capacity
|
|
CpV_T |
Saturated vapour heat capacity
|
|
CpL_T |
Saturated liquid heat capacity
|
|
Cp_pT |
Specific isobaric heat
capacity as a function of pressure and temperature. |
|
Cp_ph |
Specific isobaric heat
capacity as a function of pressure and enthalpy |
|
Cp_ps |
Specific isobaric heat
capacity as a function of pressure and entropy. |
Specific isochoric heat
capacity
|
Function |
Out |
|
CvV_p |
Saturated vapour isochoric
heat capacity |
|
CvL_p |
Saturated liquid isochoric
heat capacity |
|
CvV_T |
Saturated vapour isochoric
heat capacity |
|
CvL_T |
Saturated liquid isochoric
heat capacity |
|
Cv_pT |
Specific isochoric heat
capacity as a function of pressure and temperature. |
|
Cv_ph |
Specific isochoric heat
capacity as a function of pressure and enthalpy |
|
Cv_ps |
Specific isochoric heat
capacity as a function of pressure and entropy. |
Speed
of sound
|
Function |
Out |
|
wV_p |
Saturated vapour speed of
sound |
|
wL_p |
Saturated liquid speed of
sound |
|
wV_T |
Saturated vapour speed of
sound |
|
wL_T |
Saturated liquid speed of
sound |
|
w_pT |
Speed of sound as a function
of pressure and temperature. |
|
w_ph |
Speed of sound as a function
of pressure and enthalpy |
|
w_ps |
Speed of sound as a function
of pressure and entropy. |
Viscosity
Viscosity is not part of IAPWS Steam
IF97. Equations from "Revised Release on the IAPWS Formulation 1985
for the Viscosity of Ordinary Water Substance", 2003 are used.
Viscosity in the mixed region (4) is
interpolated according to the density. This is not true since it
will be two fases.
|
Function |
Out |
|
my_pT |
Viscosity as a function of
pressure and temperature. |
|
my_ph |
Viscosity as a function of
pressure and enthalpy |
|
my_ps |
Viscosity as a function of
pressure and entropy. |
Thermal Conductivity
Revised release on the IAPS
Formulation 1985 for the Thermal Conductivity of ordinary water
substance (IAPWS 1998)
|
Function |
Out |
|
tcL_p |
Saturated vapour thermal
conductivity |
|
tcV_p |
Saturated liquid thermal
conductivity |
|
tcL_T |
Saturated vapour thermal
conductivity |
|
tcV_T |
Saturated liquid thermal
conductivity |
|
tc_pT |
Thermal conductivity as a
function of pressure and temperature. |
|
tc_ph |
Thermal conductivity as a
function of pressure and enthalpy |
|
tc_hs |
Thermal conductivity as a
function of enthalpy and entropy |
Surface Tension
IAPWS Release on Surface Tension of
Ordinary Water Substance, September 1994
|
Function |
Out |
|
st_T |
Surface tension for two phase
water/steam as a function of T |
|
st_p |
Surface tension for two phase
water/steam as a function of T |
Vapour fraction
|
Function |
Out |
|
x_ph |
Surface tension for two phase
water/steam as a function of T |
|
x_ps |
Surface tension for two phase
water/steam as a function of T |
Vapour
Volume Fraction
Observe that vapour volume fraction is
very sensitive. Vapour volume is about 1000 times greater than
liquid volume and therefore vapour volume fraction gets close to the
accurancy of IAPWS IF-97
|
Function |
Out |
|
vx_ph |
Vapour volume fraction as a
function of pressure and enthalpy |
|
vx_ps |
Vapour volume fraction as a
function of pressure and entropy. |
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