*** empty log message ***

Cantera/python/examples/catcomb.py

@@ -1,4 +1,4 @@
-# CATCOMB  -- Catalytic combustion on platinum.
+# CATCOMB  -- Catalytic combustion of methane on platinum.
 # 
 # This script solves a catalytic combustion problem. A stagnation flow
 # is set up, with a gas inlet 10 cm from a platinum surface at 900
@@ -82,27 +82,42 @@ surf_phase.setTemperature(tsurf)
 # coverages. 
 surf_phase.advanceCoverages(1.0)
 
+# create the object that simulates the stagnation flow, and specify an
+# initial grid
 sim = StagnationFlow(gas = gas, surfchem = surf_phase,
                      grid = initial_grid)
 
+# Objects of class StagnationFlow have members that represent the gas inlet ('inlet') and the surface ('surface'). Set some parameters of these objects.
 sim.inlet.set(mdot = mdot, T = tinlet, X = comp1)
 sim.surface.set(T = tsurf)
 
+# Set error tolerances
 sim.set(tol = tol_ss, tol_time = tol_ts)
 
+# Method 'init' must be called before beginning a simulation 
 sim.init()
+
+# Show the initial solution estimate
 sim.showSolution()
 
-# start with the energy equation on
+
+
+# Solving problems with stiff chemistry coulpled to flow can require
+# a sequential approach where solutions are first obtained for
+# simpler problems and used as the initial guess for more difficult
+# problems.
+
+# start with the energy equation on (default is 'off')
 sim.set(energy = 'on')
 
 # disable the surface coverage equations, and turn off all gas and
-# surface chemistry
+# surface chemistry.
 sim.surface.setCoverageEqs('off')
 surf_phase.setMultiplier(0.0);
 gas.setMultiplier(0.0);
 
-# solve the problem, refining the grid if needed
+# solve the problem, refining the grid if needed, to determine the
+# non-reacting velocity and temperature distributions
 sim.solve(loglevel, refine_grid)
 
 # now turn on the surface coverage equations, and turn the
@@ -119,7 +134,7 @@ for iter in range(6):
 # problem.
 sim.showSolution()
 
-#Now switch the inlet to the methane/air composition.
+# Now switch the inlet to the methane/air composition.
 sim.inlet.set(X = comp2)
 
 # set more stringent grid refinement criteria
@@ -138,16 +153,19 @@ sim.save("catcomb.xml", "soln1")
 # save selected solution components in a CSV file for plotting in
 # Excel or MATLAB.
 
+# These methods return arrays containing the values at all grid points
 z = sim.flow.grid()
 T = sim.T()
 u = sim.u()
 V = sim.V()
+
 f = open('catcomb.csv','w')
-writeCSV(f, ['z (m)', 'u (m/s)', 'V (1/s)', 'T (K)']
+writeCSV(f, ['z (m)', 'u (m/s)', 'V (1/s)', 'T (K)', 'rho (kg/m3']
          + list(gas.speciesNames()))
 for n in range(sim.flow.nPoints()):
     sim.setGasState(n)
-    writeCSV(f, [z[n], u[n], V[n], T[n]]+list(gas.moleFractions()))
+    writeCSV(f, [z[n], u[n], V[n], T[n], gas.density()]
+             +list(gas.moleFractions()))
 
 # write the surface coverages to the CSV file
 cov = sim.coverages()
@@ -159,4 +177,5 @@ f.close()
 
 print 'solution saved to catcomb.csv'
 
+# show some statistics 
 sim.showStats()

Cantera/python/examples/dustygas.py

@@ -0,0 +1,30 @@
+"""
+ Dusty Gas transport model.
+
+ The Dusty Gas model is a mulicomponent transport model for gas
+ transport through the pores of a stationary porous medium. This
+ example shows how to create a transport manager that implements the
+ Dusty Gas model and use it to compute the multicomponent diffusion
+ coefficients.
+
+ """
+
+from Cantera import *
+from Cantera.DustyGasTransport import *
+
+# create a gas-phase object to represent the gas in the pores
+g = importPhase('h2o2.cti')
+
+# set the gas state
+g.setState_TPX(500.0, OneAtm, "OH:1, H:2, O2:3")
+
+# create a Dusty Gas transport manager for this phase
+d = DustyGasTransport(g)
+
+# set its parameters
+d.set(porosity = 0.2, tortuosity = 4.0,
+      pore_radius = 1.5e-7, diameter = 1.5e-6)  # lengths in meters
+
+# print the multicomponent diffusion coefficients
+print d.multiDiffCoeffs()
+

Cantera/python/examples/flame1.py

@@ -73,11 +73,12 @@ T = f.T()
 u = f.u()
 V = f.V()
 fcsv = open('flame1.csv','w')
-writeCSV(fcsv, ['z (m)', 'u (m/s)', 'V (1/s)', 'T (K)']
+writeCSV(fcsv, ['z (m)', 'u (m/s)', 'V (1/s)', 'T (K)', 'rho (kg/m3)']
          + list(gas.speciesNames()))
 for n in range(f.flame.nPoints()):
     f.setGasState(n)
-    writeCSV(fcsv, [z[n], u[n], V[n], T[n]]+list(gas.moleFractions()))
+    writeCSV(fcsv, [z[n], u[n], V[n], T[n], gas.density()]
+             +list(gas.moleFractions()))
 fcsv.close()
 
 print 'solution saved to flame1.csv'

Cantera/python/examples/flame2.py

@@ -1,8 +1,6 @@
 #
-# FLAME1 - A burner-stabilized flat flame
-#
-#    This script simulates a burner-stablized lean hydrogen-oxygen flame
-#    at low pressure.
+# FLAME2 - A burner-stabilized, premixed methane/air flat flame
+#          with multicomponent transport properties
 #
 from Cantera import *
 from Cantera.OneD import *
@@ -35,9 +33,10 @@ refine_grid = 1                     # 1 to enable refinement, 0 to
 
 ################ create the gas object ########################
 #
-# This object will be used to evaluate all thermodynamic, kinetic,
-# and transport properties
-#
+# This object will be used to evaluate all thermodynamic, kinetic, and
+# transport properties. It is created with two transport managers, to
+# enable switching from mixture-averaged to multicomponent transport
+# on the last solution.
 gas = GRI30('Mix')
 gas.addTransportModel('Multi')
 
@@ -71,19 +70,20 @@ gas.switchTransportModel('Multi')
 f.flame.setTransportModel(gas)
 f.solve(loglevel, refine_grid)
 f.save('ch4_flame1.xml','energy_multi',
-       'solution with the energy equation enabled')
+       'solution with the energy equation enabled and multicomponent transport')
 
-# write the velocity, temperature, and mole fractions to a CSV file
+# write the velocity, temperature, density, and mole fractions to a CSV file
 z = f.flame.grid()
 T = f.T()
 u = f.u()
 V = f.V()
 fcsv = open('flame2.csv','w')
-writeCSV(fcsv, ['z (m)', 'u (m/s)', 'V (1/s)', 'T (K)']
+writeCSV(fcsv, ['z (m)', 'u (m/s)', 'V (1/s)', 'T (K)', 'rho (kg/m3)']
          + list(gas.speciesNames()))
 for n in range(f.flame.nPoints()):
     f.setGasState(n)
-    writeCSV(fcsv, [z[n], u[n], V[n], T[n]]+list(gas.moleFractions()))
+    writeCSV(fcsv, [z[n], u[n], V[n], T[n], gas.density()]
+             +list(gas.moleFractions()))
 fcsv.close()
 
 print 'solution saved to flame2.csv'