[Samples] Add FlowReactor-based version of surf_pfr example

samples/python/reactors/surf_pfr.py

@@ -0,0 +1,88 @@
+"""
+This example solves a plug flow reactor problem with surface chemistry. The specific
+problem simulated is the partial oxidation of methane over a platinum catalyst in a
+packed bed reactor. This example solves the DAE system directly, using the FlowReactor
+class and the SUNDIALS IDA solver, in contrast to the approximation as a chain of
+steady-state WSRs used in surf_pfr_chain.py.
+
+Requires: cantera >= 3.0.0
+Keywords: catalysis, reactor network, surface chemistry, plug flow reactor,
+          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
+yaml_file = 'methane_pox_on_pt.yaml'
+
+output_filename = 'surf_pfr2_output.csv'
+
+#####################################################################
+
+t = tc + 273.15  # convert to Kelvin
+
+# import the model and set the initial conditions
+surf = ct.Interface(yaml_file, 'Pt_surf')
+surf.TP = t, ct.one_atm
+gas = surf.adjacent['gas']
+gas.TPX = t, ct.one_atm, 'CH4:1, O2:1.5, AR:0.1'
+
+mass_flow_rate = velocity * gas.density * area * porosity
+
+# create a new reactor
+r = ct.FlowReactor(gas, energy='off', area=area)
+r.surface_area_to_volume_ratio = cat_area_per_vol * porosity
+r.mass_flow_rate = mass_flow_rate
+r.energy_enabled = False
+
+# Add the reacting surface to the reactor
+rsurf = ct.ReactorSurface(surf, r)
+
+sim = ct.ReactorNet([r])
+
+output_data = []
+n = 0
+print('    distance       X_CH4        X_H2        X_CO')
+print('  {:10f}  {:10f}  {:10f}  {:10f}'.format(
+      0, *r.thermo['CH4', 'H2', 'CO'].X))
+
+while sim.time < length:
+    dist = sim.time * 1e3
+    sim.step()
+
+    if n % 100 == 0 or (dist > 1 and n % 10 == 0):
+        print('  {:10f}  {:10f}  {:10f}  {:10f}'.format(
+              dist, *r.thermo['CH4', 'H2', 'CO'].X))
+    n += 1
+
+    # write the gas mole fractions and surface coverages vs. distance
+    output_data.append(
+        [dist, r.T - 273.15, r.thermo.P / ct.one_atm]
+        + list(r.thermo.X)  # use r.thermo.X not gas.X
+        + list(rsurf.kinetics.coverages)  # use rsurf.kinetics.coverages not surf.coverages
+    )
+
+with open(output_filename, 'w', newline="") as outfile:
+    writer = csv.writer(outfile)
+    writer.writerow(['Distance (mm)', 'T (C)', 'P (atm)'] +
+                    gas.species_names + surf.species_names)
+    writer.writerows(output_data)
+
+print("Results saved to '{0}'".format(output_filename))

samples/python/reactors/surf_pfr_chain.py

@@ -1,7 +1,9 @@
 """
 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.
+methane over a platinum catalyst in a packed bed reactor. To avoid needing to solve a
+DAE system, the PFR is approximated as a chain of successive WSRs. See surf_pfr.py
+for a more advanced implementation that solves the DAE system directly.
 
 Requires: cantera >= 2.5.0
 Keywords: catalysis, reactor network, surface chemistry, plug flow reactor,