From 840bdfffab00fe2731aa0edfd8ecffcedb33b0ae Mon Sep 17 00:00:00 2001
From: Ray Speth <speth@mit.edu>
Date: Thu, 7 Feb 2013 23:41:30 +0000
Subject: [PATCH] [Cython] Translated more samples to use use the new API

---
 .../examples/onedim/stagnation_flame.py       |  94 +++++++++++
 .../cantera/examples/reactors/combustor.py    |  92 ++++++++++
 .../cython/cantera/examples/reactors/mix1.py  |  72 ++++++++
 .../cantera/examples/reactors/piston.py       |  90 ++++++++++
 .../cantera/examples/reactors/reactor1.py     |  63 +++++++
 .../cantera/examples/reactors/reactor2.py     | 113 +++++++++++++
 .../cantera/examples/reactors/sensitivity1.py |  92 ++++++++++
 .../cantera/examples/reactors/surf_pfr.py     | 158 ++++++++++++++++++
 8 files changed, 774 insertions(+)
 create mode 100644 interfaces/cython/cantera/examples/onedim/stagnation_flame.py
 create mode 100644 interfaces/cython/cantera/examples/reactors/combustor.py
 create mode 100644 interfaces/cython/cantera/examples/reactors/mix1.py
 create mode 100644 interfaces/cython/cantera/examples/reactors/piston.py
 create mode 100644 interfaces/cython/cantera/examples/reactors/reactor1.py
 create mode 100644 interfaces/cython/cantera/examples/reactors/reactor2.py
 create mode 100644 interfaces/cython/cantera/examples/reactors/sensitivity1.py
 create mode 100644 interfaces/cython/cantera/examples/reactors/surf_pfr.py

diff --git a/interfaces/cython/cantera/examples/onedim/stagnation_flame.py b/interfaces/cython/cantera/examples/onedim/stagnation_flame.py
new file mode 100644
index 000000000..afd7f6ddb
--- /dev/null
+++ b/interfaces/cython/cantera/examples/onedim/stagnation_flame.py
@@ -0,0 +1,94 @@
+"""
+A detached flat flame stabilized at a stagnation point
+
+This script simulates a lean hydrogen-oxygen flame stabilized in a strained
+flowfield at an axisymmetric stagnation point on a non-reacting surface. The
+solution begins with a flame attached to the inlet (burner), and the mass flow
+rate is progressively increased, causing the flame to detach and move closer
+to the surface.
+
+This example illustrates use of the new 'prune' grid refinement parameter,
+which allows grid points to be removed if they are no longer required to
+resolve the solution. This is important here, since the flamefront moves as
+the mass flowrate is increased. Without using 'prune', a large number of grid
+points would be concentrated upsteam of the flame, where the flamefront had
+been previously. (To see this, try setting prune to zero.)
+"""
+
+import cantera as ct
+import numpy as np
+import os
+
+# parameter values
+p = 0.05 * ct.one_atm  # pressure
+tburner = 373.0  # burner temperature
+tsurf = 500.0
+
+# each mdot value will be solved to convergence, with grid refinement, and
+# then that solution will be used for the next mdot
+mdot = [0.06, 0.07, 0.08, 0.09, 0.1, 0.11, 0.12]  # kg/m^2/s
+
+rxnmech = 'h2o2.cti'  # reaction mechanism file
+comp = 'H2:1.8, O2:1, AR:7'  # premixed gas composition
+
+# The solution domain is chosen to be 50 cm, and a point very near the
+# downstream boundary is added to help with the zero-gradient boundary
+# condition at this boundary.
+initial_grid = np.linspace(0.0, 0.2, 12)  # m
+
+tol_ss = [1.0e-5, 1.0e-13]  # [rtol atol] for steady-state problem
+tol_ts = [1.0e-4, 1.0e-9]  # [rtol atol] for time stepping
+loglevel = 1  # amount of diagnostic output (0 to 5)
+refine_grid = True
+
+# Grid refinement parameters
+ratio = 3
+slope = 0.1
+curve = 0.2
+prune = 0.06
+
+# Set up the problem
+gas = ct.Solution(rxnmech)
+
+# set state to that of the unburned gas at the burner
+gas.TPX = tburner, p, comp
+
+# Create the stagnation flow object with a non-reactive surface.  (To make the
+# surface reactive, supply a surface reaction mechanism. See example
+# catalytic_combustion.py for how to do this.)
+sim = ct.ImpingingJet(gas=gas, grid=initial_grid)
+
+# set the properties at the inlet
+sim.inlet.mdot = mdot[0]
+sim.inlet.X = comp
+sim.inlet.T = tburner
+
+# set the surface state
+sim.surface.T = tsurf
+
+sim.flame.set_steady_tolerances(default=tol_ss)
+sim.flame.set_transient_tolerances(default=tol_ts)
+sim.set_grid_min(1e-4)
+sim.energy_enabled = False
+
+sim.set_initial_guess(products='equil')  # assume adiabatic equilibrium products
+sim.show_solution()
+
+sim.solve(loglevel, refine_grid)
+
+sim.set_refine_criteria(ratio=ratio, slope=slope, curve=curve, prune=prune)
+sim.energy_enabled = True
+
+outfile = 'stflame1.xml'
+if os.path.exists(outfile):
+    os.remove(outfile)
+
+for m,md in enumerate(mdot):
+    sim.inlet.mdot = md
+    sim.solve(loglevel,refine_grid)
+    sim.save(outfile, 'mdot{}'.format(m), 'mdot = {} kg/m2/s'.format(md))
+
+    # write the velocity, temperature, and mole fractions to a CSV file
+    sim.write_csv('stflame1_{}.csv'.format(m), quiet=False)
+
+sim.show_stats()
diff --git a/interfaces/cython/cantera/examples/reactors/combustor.py b/interfaces/cython/cantera/examples/reactors/combustor.py
new file mode 100644
index 000000000..62e97eb35
--- /dev/null
+++ b/interfaces/cython/cantera/examples/reactors/combustor.py
@@ -0,0 +1,92 @@
+"""
+A combustor. Two separate stream - one pure methane and the other air, both at
+300 K and 1 atm flow into an adiabatic combustor where they mix. We are
+interested in the steady-state burning solution. Since at 300 K no reaction
+will occur between methane and air, we need to use an 'igniter' to initiate
+the chemistry. A simple igniter is a pulsed flow of atomic hydrogen. After the
+igniter is turned off, the system approaches the steady burning solution.
+"""
+
+import math
+import csv
+
+import cantera as ct
+
+# use reaction mechanism GRI-Mech 3.0
+
+gas = ct.Solution('gri30.xml')
+
+# create a reservoir for the fuel inlet, and set to pure methane.
+gas.TPX = 300.0, ct.one_atm, 'CH4:1.0'
+fuel_in = ct.Reservoir(gas)
+fuel_mw = gas.mean_molecular_weight
+
+# use predefined function Air() for the air inlet
+air = ct.Solution('air.xml')
+air_in = ct.Reservoir(air)
+air_mw = air.mean_molecular_weight
+
+# to ignite the fuel/air mixture, we'll introduce a pulse of radicals. The
+# steady-state behavior is independent of how we do this, so we'll just use a
+# stream of pure atomic hydrogen.
+gas.TPX = 300.0, ct.one_atm, 'H:1.0'
+igniter = ct.Reservoir(gas)
+
+# create the combustor, and fill it in initially with N2
+gas.TPX = 300.0, ct.one_atm, 'N2:1.0'
+combustor = ct.Reactor(gas)
+combustor.volume = 1.0
+
+# create a reservoir for the exhaust
+exhaust = ct.Reservoir(gas)
+
+# lean combustion, phi = 0.5
+equiv_ratio = 0.5
+
+# compute fuel and air mass flow rates
+factor = 0.1
+air_mdot = factor * 9.52 * air_mw
+fuel_mdot = factor * equiv_ratio * fuel_mw
+
+# create and install the mass flow controllers. Controllers m1 and m2 provide
+# constant mass flow rates, and m3 provides a short Gaussian pulse only to
+# ignite the mixture
+m1 = ct.MassFlowController(fuel_in, combustor, mdot=fuel_mdot)
+
+# note that this connects two reactors with different reaction mechanisms and
+# different numbers of species. Downstream and upstream species are matched by
+# name.
+m2 = ct.MassFlowController(air_in, combustor, mdot=air_mdot)
+
+# The igniter will use a Gaussian time-dependent mass flow rate.
+fwhm = 0.2
+amplitude = 0.1
+t0 = 1.0
+igniter_mdot = lambda t: amplitude * math.exp(-(t-t0)**2 * 4 * math.log(2) / fwhm**2)
+m3 = ct.MassFlowController(igniter, combustor, mdot=igniter_mdot)
+
+# put a valve on the exhaust line to regulate the pressure
+v = ct.Valve(combustor, exhaust, K=1.0)
+
+# the simulation only contains one reactor
+sim = ct.ReactorNet([combustor])
+
+# take single steps to 6 s, writing the results to a CSV file for later
+# plotting.
+tfinal = 6.0
+tnow = 0.0
+Tprev = combustor.T
+tprev = tnow
+outfile = open('combustor.csv','w')
+csvwriter = csv.writer(outfile)
+
+while tnow < tfinal:
+    tnow = sim.step(tfinal)
+    tres = combustor.mass/v.mdot(tnow)
+    Tnow = combustor.T
+    if abs(Tnow - Tprev) > 1.0 or tnow-tprev > 2e-2:
+        tprev = tnow
+        Tprev = Tnow
+        csvwriter.writerow([tnow, combustor.T, tres] +
+                            list(combustor.thermo.X))
+outfile.close()
diff --git a/interfaces/cython/cantera/examples/reactors/mix1.py b/interfaces/cython/cantera/examples/reactors/mix1.py
new file mode 100644
index 000000000..b592362f6
--- /dev/null
+++ b/interfaces/cython/cantera/examples/reactors/mix1.py
@@ -0,0 +1,72 @@
+"""
+Mixing two streams.
+
+Since reactors can have multiple inlets and outlets, they can be used to
+implement mixers, splitters, etc. In this example, air and methane are mixed
+in stoichiometric proportions. Due to the low temperature, no reactions occur.
+Note that the air stream and the methane stream use *different* reaction
+mechanisms, with different numbers of species and reactions. When gas flows
+from one reactor or reservoir to another one with a different reaction
+mechanism, species are matched by name. If the upstream reactor contains a
+species that is not present in the downstream reaction mechanism, it will be
+ignored. In general, reaction mechanisms for downstream reactors should
+contain all species that might be present in any upstream reactor.
+"""
+
+import cantera as ct
+
+# Use air for stream a.
+gas_a = ct.Solution('air.xml')
+gas_a.TPX = 300.0, ct.one_atm, 'O2:0.21, N2:0.78, AR:0.01'
+rho_a = gas_a.density
+
+
+# Use GRI-Mech 3.0 for stream b (methane) and for the mixer. If it is desired
+# to have a pure mixer, with no chemistry, use instead a reaction mechanism
+# for gas_b that has no reactions.
+gas_b = ct.Solution('gri30.xml')
+gas_b.TPX = 300.0, ct.one_atm, 'CH4:1'
+rho_b = gas_b.density
+
+# Create reservoirs for the two inlet streams and for the outlet stream.  The
+# upsteam reservoirs could be replaced by reactors, which might themselves be
+# connected to reactors further upstream. The outlet reservoir could be
+# replaced with a reactor with no outlet, if it is desired to integrate the
+# composition leaving the mixer in time, or by an arbitrary network of
+# downstream reactors.
+res_a = ct.Reservoir(gas_a)
+res_b = ct.Reservoir(gas_b)
+downstream = ct.Reservoir(gas_b)
+
+# Create a reactor for the mixer. A reactor is required instead of a
+# reservoir, since the state will change with time if the inlet mass flow
+# rates change or if there is chemistry occurring.
+gas_b.TPX = 300.0, ct.one_atm, 'O2:0.21, N2:0.78, AR:0.01'
+mixer = ct.Reactor(gas_b)
+
+# create two mass flow controllers connecting the upstream reservoirs to the
+# mixer, and set their mass flow rates to values corresponding to
+# stoichiometric combustion.
+mfc1 = ct.MassFlowController(res_a, mixer, mdot=rho_a*2.5/0.21)
+mfc2 = ct.MassFlowController(res_b, mixer, mdot=rho_b*1.0)
+
+# connect the mixer to the downstream reservoir with a valve.
+outlet = ct.Valve(mixer, downstream, K=10.0)
+
+sim = ct.ReactorNet([mixer])
+
+# Since the mixer is a reactor, we need to integrate in time to reach steady
+# state. A few residence times should be enough.
+print('{:>14s} {:>14s} {:>14s}  {:>14s}  {:>14s}'.format(
+      't [s]', 'T [K]', 'h [J/kg]', 'P [Pa]', 'X_CH4'))
+
+t = 0.0
+for n in range(30):
+    tres = mixer.mass/(mfc1.mdot(t) + mfc2.mdot(t))
+    t += 0.5*tres
+    sim.advance(t)
+    print('{:14.5g} {:14.5g} {:14.5g}  {:14.5g}  {:14.5g}'.format(
+          t, mixer.T, mixer.thermo.h, mixer.thermo.P, mixer.thermo['CH4'].X[0]))
+
+# view the state of the gas in the mixer
+print(mixer.thermo.report())
diff --git a/interfaces/cython/cantera/examples/reactors/piston.py b/interfaces/cython/cantera/examples/reactors/piston.py
new file mode 100644
index 000000000..f8a21bcb2
--- /dev/null
+++ b/interfaces/cython/cantera/examples/reactors/piston.py
@@ -0,0 +1,90 @@
+"""
+Gas 1: a stoichiometric H2/O2/Ar mixture
+Gas 2: a wet CO/O2 mixture
+
+    -------------------------------------
+    |          ||                       |
+    |          ||                       |
+    |  gas 1   ||        gas 2          |
+    |          ||                       |
+    |          ||                       |
+    -------------------------------------
+
+The two volumes are connected by an adiabatic free piston. The piston speed is
+proportional to the pressure difference between the two chambers.
+
+Note that each side uses a *different* reaction mechanism
+"""
+
+import sys
+
+import cantera as ct
+
+fmt = '%10.3f  %10.1f  %10.4f  %10.4g  %10.4g  %10.4g  %10.4g'
+print('%10s  %10s  %10s  %10s  %10s  %10s %10s' % ('time [s]','T1 [K]','T2 [K]',
+                                              'V1 [m^3]', 'V2 [m^3]',
+                                              'V1+V2 [m^3]','X(CO)'))
+
+gas1 = ct.Solution('h2o2.cti')
+gas1.TPX = 900.0, ct.one_atm, 'H2:2, O2:1, AR:20'
+
+gas2 = ct.Solution('gri30.xml')
+gas2.TPX = 900.0, ct.one_atm, 'CO:2, H2O:0.01, O2:5'
+
+r1 = ct.Reactor(gas1)
+r1.volume = 0.5
+r2 = ct.Reactor(gas2)
+r2.volume = 0.1
+w = ct.Wall(r1, r2, K=1.0e3)
+
+net = ct.ReactorNet([r1, r2])
+
+tim = []
+t1 = []
+t2 = []
+v1 = []
+v2 = []
+v = []
+xco = []
+xh2 = []
+
+for n in range(30):
+    time = (n+1)*0.002
+    net.advance(time)
+    print(fmt % (time, r1.T, r2.T, r1.volume, r2.volume,
+                 r1.volume + r2.volume, r2.thermo['CO'].X[0]))
+
+    tim.append(time * 1000)
+    t1.append(r1.T)
+    t2.append(r2.T)
+    v1.append(r1.volume)
+    v2.append(r2.volume)
+    v.append(r1.volume + r2.volume)
+    xco.append(r2.thermo['CO'].X[0])
+    xh2.append(r1.thermo['H2'].X[0])
+
+
+# plot the results if matplotlib is installed.
+if '--plot' in sys.argv:
+    import matplotlib.pyplot as plt
+    plt.subplot(2,2,1)
+    plt.plot(tim,t1,'-',tim,t2,'r-')
+    plt.xlabel('Time (ms)')
+    plt.ylabel('Temperature (K)')
+    plt.subplot(2,2,2)
+    plt.plot(tim,v1,'-',tim,v2,'r-',tim,v,'g-')
+    plt.xlabel('Time (ms)')
+    plt.ylabel('Volume (m3)')
+    plt.subplot(2,2,3)
+    plt.plot(tim,xco)
+    plt.xlabel('Time (ms)')
+    plt.ylabel('CO Mole Fraction (right)')
+    plt.subplot(2,2,4)
+    plt.plot(tim,xh2)
+    plt.xlabel('Time (ms)')
+    plt.ylabel('H2 Mole Fraction (left)')
+    plt.tight_layout()
+    plt.show()
+
+else:
+    print("""To view a plot of these results, run this script with the option --plot""")
diff --git a/interfaces/cython/cantera/examples/reactors/reactor1.py b/interfaces/cython/cantera/examples/reactors/reactor1.py
new file mode 100644
index 000000000..df21a3374
--- /dev/null
+++ b/interfaces/cython/cantera/examples/reactors/reactor1.py
@@ -0,0 +1,63 @@
+"""
+Constant-pressure, adiabatic kinetics simulation.
+"""
+
+import sys
+import numpy as np
+
+import cantera as ct
+
+gri3 = ct.Solution('gri30.xml')
+air = ct.Solution('air.xml')
+
+gri3.TPX = 1001.0, ct.one_atm, 'H2:2,O2:1,N2:4'
+r = ct.Reactor(gri3)
+env = ct.Reservoir(air)
+
+# Define a wall between the reactor and the environment, and
+# make it flexible, so that the pressure in the reactor is held
+# at the environment pressure.
+w = ct.Wall(r, env)
+w.expansion_rate_coeff = 1.0e6  # set expansion parameter. dV/dt = KA(P_1 - P_2)
+w.area = 1.0
+
+sim = ct.ReactorNet([r])
+time = 0.0
+times = np.zeros(100)
+data = np.zeros((100,4))
+
+print('%10s %10s %10s %14s' % ('t [s]','T [K]','P [Pa]','u [J/kg]'))
+for n in range(100):
+    time += 1.e-5
+    sim.advance(time)
+    times[n] = time * 1e3  # time in ms
+    data[n,0] = r.T
+    data[n,1:] = r.thermo['OH','H','H2'].X
+    print('%10.3e %10.3f %10.3f %14.6e' % (sim.time, r.T,
+                                           r.thermo.P, r.thermo.u))
+
+# Plot the results if matplotlib is installed.
+# See http://matplotlib.org/ to get it.
+if '--plot' in sys.argv[1:]:
+    import matplotlib.pyplot as plt
+    plt.clf()
+    plt.subplot(2, 2, 1)
+    plt.plot(times, data[:,0])
+    plt.xlabel('Time (ms)')
+    plt.ylabel('Temperature (K)')
+    plt.subplot(2, 2, 2)
+    plt.plot(times, data[:,1])
+    plt.xlabel('Time (ms)')
+    plt.ylabel('OH Mole Fraction')
+    plt.subplot(2, 2, 3)
+    plt.plot(times, data[:,2])
+    plt.xlabel('Time (ms)')
+    plt.ylabel('H Mole Fraction')
+    plt.subplot(2, 2, 4)
+    plt.plot(times,data[:,3])
+    plt.xlabel('Time (ms)')
+    plt.ylabel('H2 Mole Fraction')
+    plt.tight_layout()
+    plt.show()
+else:
+    print("To view a plot of these results, run this script with the option --plot")
diff --git a/interfaces/cython/cantera/examples/reactors/reactor2.py b/interfaces/cython/cantera/examples/reactors/reactor2.py
new file mode 100644
index 000000000..4a58f25e6
--- /dev/null
+++ b/interfaces/cython/cantera/examples/reactors/reactor2.py
@@ -0,0 +1,113 @@
+"""
+This script simulates the following situation. A closed cylinder with volume 2
+m^3 is divided into two equal parts by a massless piston that moves with speed
+proportional to the pressure difference between the two sides.  It is
+initially held in place in the middle. One side is filled with 1000 K argon at
+20 atm, and the other with a combustible 500 K methane/air mixture at 0.1 atm
+(phi = 1.1). At t = 0 the piston is released and begins to move due to the
+large pressure difference, compressing and heating the methane/air mixture,
+which eventually explodes. At the same time, the argon cools as it expands.
+The piston is adiabatic, but some heat is lost through the outer cylinder
+walls to the environment.
+
+Note that this simulation, being zero-dimensional, takes no account of shock
+wave propagation. It is somewhat artifical, but nevertheless instructive.
+"""
+
+import sys
+import os
+import csv
+import numpy as np
+
+import cantera as ct
+
+#-----------------------------------------------------------------------
+# First create each gas needed, and a reactor or reservoir for each one.
+#-----------------------------------------------------------------------
+
+# create an argon gas object and set its state
+ar = ct.Solution('argon.xml')
+ar.TP = 1000.0, 20.0 * ct.one_atm
+
+# create a reactor to represent the side of the cylinder filled with argon
+r1 = ct.Reactor(ar)
+
+# create a reservoir for the environment, and fill it with air.
+env = ct.Reservoir(ct.Solution('air.xml'))
+
+# use GRI-Mech 3.0 for the methane/air mixture, and set its initial state
+gri3 = ct.Solution('gri30.xml')
+gri3.TPX = 500.0, 0.2 * ct.one_atm, 'CH4:1.1, O2:2, N2:7.52'
+
+# create a reactor for the methane/air side
+r2 = ct.Reactor(gri3)
+
+#-----------------------------------------------------------------------------
+# Now couple the reactors by defining common walls that may move (a piston) or
+# conduct heat
+#-----------------------------------------------------------------------------
+
+# add a flexible wall (a piston) between r2 and r1
+w = ct.Wall(r2, r1, A=1.0, K=0.5e-4, U=100.0)
+
+# heat loss to the environment. Heat loss always occur through walls, so we
+# create a wall separating r1 from the environment, give it a non-zero area,
+# and specify the overall heat transfer coefficient through the wall.
+w2 = ct.Wall(r2, env, A=1.0, U=500.0)
+
+sim = ct.ReactorNet([r1, r2])
+
+# Now the problem is set up, and we're ready to solve it.
+print('finished setup, begin solution...')
+
+time = 0.0
+n_steps = 300
+outfile = open('piston.csv', 'w')
+csvfile = csv.writer(outfile)
+csvfile.writerow(['time (s)','T1 (K)','P1 (Bar)','V1 (m3)',
+                  'T2 (K)','P2 (Bar)','V2 (m3)'])
+temp = np.zeros((n_steps, 2))
+pres = np.zeros((n_steps, 2))
+vol = np.zeros((n_steps, 2))
+tm = np.zeros(n_steps)
+
+for n in range(n_steps):
+    time += 4.e-4
+    print(n, time, r2.T)
+    sim.advance(time)
+    tm[n] = time
+    temp[n,:] = r1.T, r2.T
+    pres[n,:] = 1.0e-5*r1.thermo.P, 1.0e-5*r2.thermo.P
+    vol[n,:] = r1.volume, r2.volume
+    csvfile.writerow([tm[n], temp[n,0], pres[n,0], vol[n,0],
+                      temp[n,1], pres[n,1], vol[n,1]])
+outfile.close()
+print('Output written to file piston.csv')
+print('Directory: '+os.getcwd())
+
+if '--plot' in sys.argv:
+    import matplotlib.pyplot as plt
+    plt.clf()
+    plt.subplot(2,2,1)
+    h = plt.plot(tm, temp[:,0],'g-',tm, temp[:,1],'b-')
+    #plt.legend(['Reactor 1','Reactor 2'],2)
+    plt.xlabel('Time (s)')
+    plt.ylabel('Temperature (K)')
+
+    plt.subplot(2,2,2)
+    plt.plot(tm, pres[:,0],'g-',tm, pres[:,1],'b-')
+    #plt.legend(['Reactor 1','Reactor 2'],2)
+    plt.xlabel('Time (s)')
+    plt.ylabel('Pressure (Bar)')
+
+    plt.subplot(2,2,3)
+    plt.plot(tm, vol[:,0],'g-',tm, vol[:,1],'b-')
+    #plt.legend(['Reactor 1','Reactor 2'],2)
+    plt.xlabel('Time (s)')
+    plt.ylabel('Volume (m$^3$)')
+
+    plt.figlegend(h, ['Reactor 1', 'Reactor 2'], loc='lower right')
+    plt.tight_layout()
+    plt.show()
+else:
+    print("""To view a plot of these results, run this script with the option -plot""")
diff --git a/interfaces/cython/cantera/examples/reactors/sensitivity1.py b/interfaces/cython/cantera/examples/reactors/sensitivity1.py
new file mode 100644
index 000000000..1257daecb
--- /dev/null
+++ b/interfaces/cython/cantera/examples/reactors/sensitivity1.py
@@ -0,0 +1,92 @@
+"""
+Constant-pressure, adiabatic kinetics simulation with sensitivity analysis
+"""
+
+import sys
+import numpy as np
+
+import cantera as ct
+
+gri3 = ct.Solution('gri30.xml')
+temp = 1500.0
+pres = ct.one_atm
+
+gri3.TPX = temp, pres, 'CH4:0.1, O2:2, N2:7.52'
+r = ct.Reactor(gri3)
+
+air = ct.Solution('air.xml')
+air.TP = temp, pres
+env = ct.Reservoir(air)
+
+# Define a wall between the reactor and the environment, and make it flexible,
+# so that the pressure in the reactor is held at the environment pressure.
+w = ct.Wall(r, env)
+w.expansion_rate_coeff = 1.0e6  # set expansion parameter. dV/dt = KA(P_1 - P_2)
+w.area = 1.0
+
+sim = ct.ReactorNet([r])
+
+# enable sensitivity with respect to the rates of the first 10
+# reactions (reactions 0 through 9)
+for i in range(10):
+    r.add_sensitivity_reaction(i)
+
+# set the tolerances for the solution and for the sensitivity coefficients
+sim.rtol = 1.0e-6
+sim.atol = 1.0e-15
+sim.rtol_sensitivity = 1.0e-6
+sim.atol_sensitivity = 1.0e-6
+
+
+n_times = 400
+tim = np.zeros(n_times)
+data = np.zeros((n_times,6))
+
+time = 0.0
+for n in range(n_times):
+    time += 5.0e-6
+    sim.advance(time)
+    tim[n] = 1000 * time
+    data[n,0] = r.T
+    data[n,1:4] = r.thermo['OH','H','CH4'].X
+
+    # sensitivity of OH to reaction 2
+    data[n,4] = sim.sensitivity('OH',2)
+
+    # sensitivity of OH to reaction 3
+    data[n,5] = sim.sensitivity('OH',3)
+
+    print('%10.3e %10.3f %10.3f %14.6e %10.3f %10.3f' %
+          (sim.time, r.T, r.thermo.P, r.thermo.u,  data[n,4],  data[n,5]))
+
+# plot the results if matplotlib is installed.
+# see http://matplotlib.org/ to get it
+if '--plot' in sys.argv:
+    import matplotlib.pyplot as plt
+    plt.subplot(2,2,1)
+    plt.plot(tim,data[:,0])
+    plt.xlabel('Time (ms)')
+    plt.ylabel('Temperature (K)')
+    plt.subplot(2,2,2)
+    plt.plot(tim,data[:,1])
+    plt.xlabel('Time (ms)')
+    plt.ylabel('OH Mole Fraction')
+    plt.subplot(2,2,3)
+    plt.plot(tim,data[:,2])
+    plt.xlabel('Time (ms)')
+    plt.ylabel('H Mole Fraction')
+    plt.subplot(2,2,4)
+    plt.plot(tim,data[:,3])
+    plt.xlabel('Time (ms)')
+    plt.ylabel('H2 Mole Fraction')
+    plt.tight_layout()
+
+    plt.figure(2)
+    plt.plot(tim,data[:,4],'-',tim,data[:,5],'-g')
+    plt.legend([sim.sensitivity_parameter_name(2),sim.sensitivity_parameter_name(3)],'best')
+    plt.xlabel('Time (ms)')
+    plt.ylabel('OH Sensitivity')
+    plt.tight_layout()
+    plt.show()
+else:
+    print("""To view a plot of these results, run this script with the option '--plot""")
diff --git a/interfaces/cython/cantera/examples/reactors/surf_pfr.py b/interfaces/cython/cantera/examples/reactors/surf_pfr.py
new file mode 100644
index 000000000..4f5bbef24
--- /dev/null
+++ b/interfaces/cython/cantera/examples/reactors/surf_pfr.py
@@ -0,0 +1,158 @@
+"""
+This example solves a plug flow reactor problem, where the chemistry is
+surface chemistry. The specific problem simulated is the partial oxidation of
+methane over a platinum catalyst in a packed bed reactor.
+"""
+
+import csv
+
+import cantera as ct
+
+# unit conversion factors to SI
+cm = 0.01
+minute = 60.0
+
+#######################################################################
+# Input Parameters
+#######################################################################
+
+tc = 800.0  # Temperature in Celsius
+length = 0.3 * cm  # Catalyst bed length
+area = 1.0 * cm**2  # Catalyst bed area
+cat_area_per_vol = 1000.0 / cm  # Catalyst particle surface area per unit volume
+velocity = 40.0 * cm / minute  # gas velocity
+porosity = 0.3  # Catalyst bed porosity
+
+# input file containing the surface reaction mechanism
+cti_file = 'methane_pox_on_pt.cti'
+
+output_filename = 'surf_pfr_output.csv'
+
+# The PFR will be simulated by a chain of 'NReactors' stirred reactors.
+NReactors = 201
+dt = 1.0
+
+#####################################################################
+
+t = tc + 273.15  # convert to Kelvin
+
+# import the gas model and set the initial conditions
+gas = ct.Solution(cti_file, 'gas')
+gas.TPX = t, ct.one_atm, 'CH4:1, O2:1.5, AR:0.1'
+
+# import the surface model
+surf = ct.Interface(cti_file,'Pt_surf', [gas])
+surf.TP = t, ct.one_atm
+
+rlen = length/(NReactors-1)
+rvol = area * rlen * porosity
+
+outfile = open(output_filename,'w')
+writer = csv.writer(outfile)
+writer.writerow(['Distance (mm)', 'T (C)', 'P (atm)'] +
+                gas.species_names + surf.species_names)
+
+# catalyst area in one reactor
+cat_area = cat_area_per_vol * rvol
+
+mass_flow_rate = velocity * gas.density * area
+
+# The plug flow reactor is represented by a linear chain of zero-dimensional
+# reactors. The gas at the inlet to the first one has the specified inlet
+# composition, and for all others the inlet composition is fixed at the
+# composition of the reactor immediately upstream. Since in a PFR model there
+# is no diffusion, the upstream reactors are not affected by any downstream
+# reactors, and therefore the problem may be solved by simply marching from
+# the first to last reactor, integrating each one to steady state.
+
+TDY = gas.TDY
+cov = surf.coverages
+
+print(('  {:>10s}'*4).format('distance', 'X_CH4', 'X_H2', 'X_CO'))
+
+for n in range(NReactors):
+    surf.TP = TDY[0], ct.one_atm
+    surf.coverages = cov
+
+    # create a new reactor
+    gas.TDY = TDY
+    r = ct.Reactor(gas, energy='off')
+    r.volume = rvol
+
+    # create a reservoir to represent the reactor immediately upstream. Note
+    # that the gas object is set already to the state of the upstream reactor
+    upstream = ct.Reservoir(gas, name='upstream')
+
+    # create a reservoir for the reactor to exhaust into. The composition of
+    # this reservoir is irrelevant.
+    downstream = ct.Reservoir(gas, name='downstream')
+
+    # use a 'Wall' object to implement the reacting surface in the reactor.
+    # Since walls have to be installed between two reactors/reserviors, we'll
+    # install it between the upstream reservoir and the reactor.  The area is
+    # set to the desired catalyst area in the reactor, and surface reactions
+    # are included only on the side facing the reactor.
+    w = ct.Wall(upstream, r, A=cat_area, kinetics=[None, surf])
+
+    # We need a valve between the reactor and the downstream reservoir. This
+    # will determine the pressure in the reactor. Set K large enough that the
+    # pressure difference is very small.
+    v = ct.Valve(r, downstream, K=1e-4)
+
+    # The mass flow rate into the reactor will be fixed by using a
+    # MassFlowController object.
+    m = ct.MassFlowController(upstream, r, mdot=mass_flow_rate)
+
+    sim = ct.ReactorNet([r])
+    sim.max_err_test_fails = 12
+
+    # set relative and absolute tolerances on the simulation
+    sim.rtol = 1.0e-9
+    sim.atol = 1.0e-21
+
+    T_start, rho_start, Y_start = r.thermo.TDY
+    cov_start = surf.coverages
+    V_start = r.volume
+
+    Tu_start, rhou_start, Yu_start = upstream.thermo.TDY
+
+    time = 0
+    all_done = False
+    while not all_done:
+        time += dt
+        sim.advance(time)
+
+        # check whether surface coverages are in steady state. This will be
+        # the case if the creation and destruction rates for a surface (but
+        # not gas) species are equal.
+        all_done = True
+
+        # Note: netProduction = creation - destruction. By supplying the
+        # surface object as an argument, only the values for the surface
+        # species are returned by these methods
+        sdot = surf.get_net_production_rates(surf)
+        cdot = surf.get_creation_rates(surf)
+        ddot = surf.get_destruction_rates(surf)
+
+        for ks in range(surf.n_species):
+            ratio = abs(sdot[ks]/(cdot[ks] + ddot[ks]))
+            if ratio > 1.0e-9 or time < 10*dt:
+                all_done = False
+
+    # Save the reactor and surface states, in preparation for the simulation
+    # of the next reactor downstream, where this object will set the inlet
+    # conditions and the initial surface coverages
+    TDY = r.thermo.TDY
+    cov = surf.coverages
+
+    dist = n * rlen * 1.0e3   # distance in mm
+
+    if not n % 10:
+        print(('  {:10f}'*4).format(dist, *gas['CH4','H2','CO'].X))
+
+    # write the gas mole fractions and surface coverages vs. distance
+    writer.writerow([dist, r.T - 273.15, r.thermo.P/ct.one_atm] +
+                    list(gas.X) + list(surf.coverages))
+
+outfile.close()
+print("Results saved to '{}'".format(output_filename))