Tutorial and Demos¶
Usage¶
Simple Example:
from pyXSteam.XSteam import XSteam
steam_table = XSteam(XSteam.UNIT_SYSTEM_MKS)
print steam_table.hL_p(220.0)
By using the unitSystem Parameter, you can tell XSteam witch Unit System you are using.:
steam_table = XSteam(XSteam.UNIT_SYSTEM_MKS) # m/kg/sec/°C/bar/W
steam_table = XSteam(XSteam.UNIT_SYSTEM_FLS) # ft/lb/sec/°F/psi/btu
steam_table = XSteam(XSteam.UNIT_SYSTEM_BARE) # m/kg/sec/K/MPa/W
To enable logging, add the following lines to your code:
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)
Calculate single values¶
This is a simple example:
>>> from pyXSteam.XSteam import XSteam
>>> steam_table = XSteam(XSteam.UNIT_SYSTEM_MKS)
>>> steam_table.hL_p(220.0)
2021.909286172027
>>> steam_table.tcV_p(1)
0.02475366759235046
Generate Diagrams¶
Diagrams based on the calculated values can easily be created using numpy and matplotlib.
Example: To draw a T(p) diagram showing the saturation curve:
from pyXSteam.XSteam import XSteam
import matplotlib.pyplot as pyplot
import numpy as np
steam_table = XSteam(XSteam.UNIT_SYSTEM_MKS)
p = np.arange(-100.0, 250.0, 1.0)
ntsat_p = np.frompyfunc(steam_table.tsat_p, 1, 1)
tsat = ntsat_p(p)
line1, = pyplot.plot(tsat, p)
pyplot.xlabel("t")
pyplot.ylabel("p")
pyplot.setp(line1, linewidth=1, color='b')
pyplot.show()
For more demos, see pyXSteamDemo.py
Heavy Water functions¶
The functions to calculate values for heavy water are available through the class XSteamHW
>>> from pyXSteam.XSteamHW import XSteamHW
>>> steam_table = XSteamHW(XSteam.UNIT_SYSTEM_MKS)
>>> steam_table.my_rhoT(1.2, 300.0)
#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""collection of demos presenting the functionality of pyXSteam"""
import time
import logging
from mpl_toolkits.mplot3d import Axes3D
import matplotlib.pyplot as pyplot
import numpy as np
from pyXSteam.XSteam import XSteam
from pyXSteam.XSteam_HW import XSteam_HW
def demo_simpel_values():
"""calculate values and print the results"""
steam_table = XSteam(XSteam.UNIT_SYSTEM_MKS)
# get saturated liquid enthalpy for a preasure of 220 bar
print("hV_p(220.0) =", steam_table.hL_p(220.0))
# get saturated vapour enthalpy for a preasure of 220 bar
print("hV_p(220.0) =", steam_table.hV_p(220.0))
print("tcL_p(1.0) =", steam_table.tcL_p(1.0))
print("tcL_t(25.0) =", steam_table.tcL_t(25.0))
print("tcV_p(1.0) =", steam_table.tcV_p(1.0))
print("tcL_t(25.0) =", steam_table.tcV_t(25.0))
print("tc_hs(100.0, 0.34) =", steam_table.tc_hs(100.0, 0.34))
print("tc_ph(1.0, 100.0) =", steam_table.tc_ph(1.0, 100.0))
print("tc_pt(1.0, 25.0) =", steam_table.tc_pt(1.0, 25.0))
print("w_ps(1.0, 1.0) =", steam_table.w_ps(1.0, 1.0))
def demo_generate_ph_diagramm(path=None, precision=1.0):
"""Generate a p(h) Diagram showing the Saturation Line"""
steam_table = XSteam(XSteam.UNIT_SYSTEM_MKS)
p_krit = (
steam_table.criticalPressure() - 0.0001
) # minus 0.0001 or else hL_V returns NaN
h_krit = steam_table.hL_p(p_krit)
p = np.arange(0.0, 1000, precision)
p2 = np.arange(0.5, p_krit, precision)
vapor_fraction = np.arange(0.1, 1.0, 0.1)
h = np.arange(200.0, 4500.0, 100.0)
rho = np.arange(1, 15.0, precision * 2)
nph_px = np.frompyfunc(steam_table.h_px, 2, 1)
nph_pt = np.frompyfunc(steam_table.h_pt, 2, 1)
nphL_p = np.frompyfunc(steam_table.hL_p, 1, 1)
nphV_p = np.frompyfunc(steam_table.hV_p, 1, 1)
npp_hrho = np.frompyfunc(steam_table.p_hrho, 2, 1)
# Siede und Taulinie
hL = nphL_p(p)
hV = nphV_p(p)
# Dampfgehalt
for vf in vapor_fraction:
h_px = nph_px(p2, vf)
(line,) = pyplot.plot(h_px, p2)
pyplot.setp(line, linewidth=1, color="g")
# Temperature
for temp in range(0, 900, 30):
h_pt = nph_pt(p, temp)
(line,) = pyplot.plot(h_pt, p)
pyplot.setp(line, linewidth=1, color="r")
# Dichte
for r in rho:
p_hrho = npp_hrho(h, r)
(line,) = pyplot.plot(h, p_hrho)
pyplot.setp(line, linewidth=1, color="y")
# Kritischer Punkt
pyplot.plot([h_krit], [p_krit], marker="s", mfc="k", ms=8)
(line1,) = pyplot.plot(hL, p)
(line2,) = pyplot.plot(hV, p)
pyplot.xlabel("h in [kJ/kg]")
pyplot.ylabel("p in [bar]")
pyplot.setp(line1, linewidth=2, color="b")
pyplot.setp(line2, linewidth=2, color="r")
pyplot.yscale("log")
pyplot.grid()
if path is None:
pyplot.show()
else:
pyplot.savefig(path, bbox_inches="tight")
def demo_generate_Tp_diagramm():
"""Generate a T(p) Diagram showing the Saturation Curve"""
steam_table = XSteam(XSteam.UNIT_SYSTEM_MKS)
p = np.arange(-100.0, 250.0, 1.0)
ntsat_p = np.frompyfunc(steam_table.tsat_p, 1, 1)
tsat = ntsat_p(p)
(line1,) = pyplot.plot(tsat, p)
pyplot.xlabel("t")
pyplot.ylabel("p")
pyplot.setp(line1, linewidth=1, color="b")
pyplot.show()
def demo_generate_pvT_diagramm():
"""Generate a Diagram showing the v(p,T) as a 3D survace"""
steam_table = XSteam(XSteam.UNIT_SYSTEM_MKS)
fig = pyplot.figure()
ax = Axes3D(fig)
p = np.arange(-10.0, 300.0, 5.0)
t = np.arange(-50.0, 400.0, 5.0)
p, t = np.meshgrid(p, t)
npv_pt = np.frompyfunc(steam_table.v_pt, 2, 1)
v = npv_pt(p, t)
ax.plot_surface(v, p, t, rstride=1, cstride=1, linewidth=0, shade=True)
ax.set_xlabel("v")
ax.set_ylabel("p")
ax.set_zlabel("t")
pyplot.show()
def demo_moillier_diagramm():
"""Generate a moillier diagram"""
steam_table = XSteam(XSteam.UNIT_SYSTEM_MKS)
s = np.arange(2.0, 10.0, 0.01)
pSteps = [0.006117, 0.01, 0.02, 1.0, 2.0, 3.0, 10, 100, 1000]
nph_ps = np.frompyfunc(steam_table.h_ps, 2, 1)
for pstep in pSteps:
h = nph_ps(pstep, s)
(hline,) = pyplot.plot(s, h)
pyplot.setp(hline, linewidth=1, color="b")
pyplot.xlabel("s in [kJ/(kg K)]")
pyplot.ylabel("h in [kJ/kg]")
pyplot.show()
def demo_ice_diagramm():
"""Generate a diagram showing the sublimation and melting preasure"""
steam_table = XSteam(XSteam.UNIT_SYSTEM_BARE)
t_subl = np.arange(50.0, 273.16, 2.0)
t_melt_Ih = np.arange(251.165, 273.16, 2.0)
t_melt_III = np.arange(251.165, 256.164, 2.0)
t_melt_V = np.arange(256.164, 273.31, 2.0)
t_melt_VI = np.arange(273.31, 355.0, 2.0)
t_melt_VII = np.arange(355.0, 751.0, 2.0)
psubl_func = np.frompyfunc(steam_table.psubl_t, 1, 1)
pmelt_func = np.frompyfunc(steam_table.pmelt_t, 2, 1)
(line1,) = pyplot.plot(t_subl, psubl_func(t_subl))
(line2,) = pyplot.plot(t_melt_Ih, pmelt_func(t_melt_Ih, steam_table.TYPE_ICE_Ih))
(line3,) = pyplot.plot(t_melt_III, pmelt_func(t_melt_III, steam_table.TYPE_ICE_III))
(line4,) = pyplot.plot(t_melt_V, pmelt_func(t_melt_V, steam_table.TYPE_ICE_V))
(line5,) = pyplot.plot(t_melt_VI, pmelt_func(t_melt_VI, steam_table.TYPE_ICE_VI))
(line6,) = pyplot.plot(t_melt_VII, pmelt_func(t_melt_VII, steam_table.TYPE_ICE_VII))
pyplot.xlabel("T in [K]")
pyplot.ylabel("p in [MPa]")
pyplot.setp(line1, linewidth=1, color="b")
pyplot.setp(line2, linewidth=1, color="g")
pyplot.setp(line3, linewidth=1, color="r")
pyplot.setp(line4, linewidth=1, color="y")
pyplot.setp(line5, linewidth=1, color="g")
pyplot.setp(line6, linewidth=1, color="r")
pyplot.show()
def demo_simpel_values_heavy_water():
"""calculate values for heavy water and print the results"""
steam_table_hw = XSteam_HW(XSteam_HW.UNIT_SYSTEM_MKS)
print("my_rhoT(1.0, 320.0) =", steam_table_hw.my_rhoT(1.0, 320.0))
print("my_rhoT(1.0, 320.0) =", steam_table_hw.tc_rhoT(1.0, 320.0))
if __name__ == "__main__":
logger = logging.getLogger("pyXSteam")
logger.setLevel(logging.DEBUG)
sh = logging.StreamHandler()
sh.setFormatter(logging.Formatter("%(name)s - %(levelname)s - %(message)s"))
logger.addHandler(sh)
print("Select which demo to run:")
print("1. Run simple calculations")
print("2. generate ph diagram")
print("3. generate Tp diagram")
print("4. generate pvT diagram")
print("5. generate moillier diagram")
print("6. generate ice metling and sublimation diagram")
print("7. Run sinple calculations for heavy water")
selection = str(input("Please enter selection [1-7]: "))
print("You selected " + selection)
if selection == "1":
start = time.process_time()
demo_simpel_values()
print("Demo took", time.process_time() - start, "seconds to complete")
elif selection == "2":
start = time.process_time()
demo_generate_ph_diagramm()
print("Demo took", time.process_time() - start, "seconds to complete")
elif selection == "3":
start = time.process_time()
demo_generate_Tp_diagramm()
print("Demo took", time.process_time() - start, "seconds to complete")
elif selection == "4":
start = time.process_time()
demo_generate_pvT_diagramm()
print("Demo took", time.process_time() - start, "seconds to complete")
elif selection == "5":
start = time.process_time()
demo_moillier_diagramm()
print("Demo took", time.process_time() - start, "seconds to complete")
elif selection == "6":
start = time.process_time()
demo_ice_diagramm()
print("Demo took", time.process_time() - start, "seconds to complete")
elif selection == "7":
start = time.process_time()
demo_simpel_values_heavy_water()
print("Demo took", time.process_time() - start, "seconds to complete")
else:
print("Unknown selection")