Skip to content

Latest commit

 

History

History
265 lines (216 loc) · 14.7 KB

README.md

File metadata and controls

265 lines (216 loc) · 14.7 KB

XSteam

Original Released by Magnus Holmgren for Matlab and Excel: http://xsteam.sourceforge.net and/or http://www.x-eng.com

At this github repository you can find the/a matlab version.

A .NET implementation is availible thanks to the work of rogerlew here: XSteamNET.

XSteam provides (mostly) accurate steam and water properties from 0 - 1000 bar and from 0 - 2000 °C according to the IAPWS release IF-97. For accuracy of the functions in different regions see IF-97 Page 4

Also includes thermal conductivity and viscosity, which are not part of the IF97 release.

Some effort has been made to include the refined function of more recent releases and also functions for calculations on heavy water. This includes:

  • IAPWS R4
  • IAPWS R14

Contributors to pyXSteam

In chronological order:

  • IAPWS
  • Magnus Holmgren
  • drunsinn
  • mohit0749
  • gonmolina
  • xjtu-blacksmith

Requirements

There are no requirements for installing pyXSteam with Python 3.6 and up.

Tests require numpy, demos require numpy and matplotlib

Install

run python3 setup.py install

To run unittests you need two additional packages: pytest and numpy. After installing both, just run pytest in the base directory. The tests use some fixed values from the documentation to make sure that every coefficient and formula works as intended.

To test if setup was successful, run python3 bin/pyXSteamDemo.py. This will require numpy and matplotlib to be installed.

Nomenclature

All Functions follow the same naming schema: First the wanted property, then a underscore _, then the wanted input properties Example: t_ph is temperature as a function of pressure and enthalpy. For a list of valid functions se below:

Property Description
t Temperature (°C or °F)
p Pressure (bar or psi)
h Enthalpy (kJ/kg or btu/lb)
v Specific volume (m3/kg or ft^3/lb)
rho Density (kg/m3 or lb/ft^3)
s Specific entropy (kJ/(kg °C) or btu/(lb °F))
u Specific internal energy (kJ/kg or btu/lb)
Cp Specific isobaric heat capacity (kJ/(kg °C) or btu/(lb °F))
Cv Specific isochoric heat capacity (kJ/(kg °C) or btu/(lb °F))
w Speed of sound (m/s or ft/s)
my Viscosity (N s/m^2 or lbm/ft/hr)
tc Thermal Conductivity (W/(m °C) or btu/(h ft °F))
st Surface Tension (N/m or lb/ft)
x Vapor fraction
vx Vapor Volume Fraction

Usage

Simple Example:

from pyXSteam.XSteam import XSteam
steamTable = XSteam(XSteam.UNIT_SYSTEM_MKS)
print(steamTable.hL_p(220.0))

By using the unitSystem Parameter, you can tell XSteam witch Unit System you are using.

steamTable = XSteam(XSteam.UNIT_SYSTEM_MKS) # m/kg/sec/°C/bar/W
steamTable = XSteam(XSteam.UNIT_SYSTEM_FLS) # ft/lb/sec/°F/psi/btu
steamTable = XSteam(XSteam.UNIT_SYSTEM_BARE) # m/kg/sec/K/MPa/W

To enable logging, add the following lines to your code:

import logging
logging.basicConfig(level=logging.INFO)

or alternatively

import logging
logger = logging.getLogger('pyXSteam')
logger.setLevel(logging.DEBUG)
sh = logging.StreamHandler()
sh.setFormatter(logging.Formatter('%(name)s - %(levelname)s - %(message)s'))
logger.addHandler(sh)

Available Functions

Temperature

Function Description
tsat_p Saturation temperature
t_ph Temperature as a function of pressure and enthalpy
t_ps Temperature as a function of pressure and entropy
t_hs Temperature as a function of enthalpy and entropy

Pressure

Function Description
psat_t Saturation pressure
p_hs Pressure as a function of h and s.
p_hrho Pressure as a function of h and rho. Very inaccurate for solid water region since it's almost incompressible!
pmelt_t Pressure as a function of temperature along the melting curve. Optional parameter to select ice region
psubl_t Pressure as a function of temperature along the sublimation curve.

Enthalpy

Function Description
hV_p Saturated vapor enthalpy
hL_p Saturated liquid enthalpy
hV_t Saturated vapor enthalpy
hL_t Saturated liquid enthalpy
h_pt Enthalpy as a function of pressure and temperature
h_ps Enthalpy as a function of pressure and entropy
h_px Enthalpy as a function of pressure and vapor fraction
h_prho Enthalpy as a function of pressure and density. Observe for low temperatures (liquid) this equation has 2 solutions
h_tx Enthalpy as a function of temperature and vapor fraction

Specific volume

Function Description
vV_p Saturated vapor volume
vL_p Saturated liquid volume
vV_t Saturated vapor 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 Description
rhoV_p Saturated vapor density
rhoL_p Saturated liquid density
rhoV_t Saturated vapor 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 Description
sV_p Saturated vapor entropy
sL_p Saturated liquid entropy
sV_t Saturated vapor entropy
sL_t Saturated liquid entropy
s_pt Specific entropy as a function of pressure and temperature (Returns saturated vapor enthalpy if mixture)
s_ph Specific entropy as a function of pressure and enthalpy

Specific internal energy

Function Description
uV_p Saturated vapor internal energy
uL_p Saturated liquid internal energy
uV_t Saturated vapor 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 Description
CpV_p Saturated vapor heat capacity
CpL_p Saturated liquid heat capacity
CpV_t Saturated vapor 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 Description
CvV_p Saturated vapor isochoric heat capacity
CvL_p Saturated liquid isochoric heat capacity
CvV_t Saturated vapor 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 Description
wV_p Saturated vapor speed of sound
wL_p Saturated liquid speed of sound
wV_t Saturated vapor 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

Function Description
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

Function Description
tcL_p Saturated vapor thermal conductivity
tcV_p Saturated liquid thermal conductivity
tcL_t Saturated vapor 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

Function Description
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 p

vapor fraction

Function Description
x_ph vapor fraction as a function of pressure and enthalpy
x_ps vapor fraction as a function of pressure and entropy

vapor volume fraction

Function Description
vx_ph vapor volume fraction as a function of pressure and enthalpy
vx_ps vapor volume fraction as a function of pressure and entropy

Pressure along the Melting and Sublimation Curves

Function Description
pmelt_t Pressure along the melting curve as a function of temperature
vx_psubl_tps Pressure along the sublimation curve as a function of temperature

Available Functions for Heavy Water

Function Description
my_rhoT Viscosity as a function of density and temperature
tc_rhoT Thermal conductivity as a function of density and temperature

Development

  • pull requests are always wellcome!
  • code style is enforced by black