[1D] Provide reasonable initial grid for BurnerFlame

doc/sphinx/cython/onedim.rst

@@ -17,7 +17,7 @@ FreeFlame
 
 BurnerFlame
 ^^^^^^^^^^^
-.. autoclass:: BurnerFlame(gas, grid=None)
+.. autoclass:: BurnerFlame(gas, grid=None, width=None)
 
 CounterflowDiffusionFlame
 ^^^^^^^^^^^^^^^^^^^^^^^^^

interfaces/cython/cantera/examples/onedim/burner_flame.py

@@ -10,7 +10,7 @@ tburner = 373.0
 mdot = 0.06
 reactants = 'H2:1.5, O2:1, AR:7'  # premixed gas composition
 
-initial_grid = np.linspace(0.0, 0.5, 10) # m
+width = 0.5 # m
 tol_ss = [1.0e-5, 1.0e-13]  # [rtol atol] for steady-state problem
 tol_ts = [1.0e-4, 1.0e-10]  # [rtol atol] for time stepping
 loglevel = 1  # amount of diagnostic output (0 to 5)
@@ -19,7 +19,7 @@ refine_grid = 1  # 1 to enable refinement, 0 to disable
 gas = ct.Solution('h2o2.xml')
 gas.TPX = tburner, p, reactants
 
-f = ct.BurnerFlame(gas, initial_grid)
+f = ct.BurnerFlame(gas, width=width)
 f.burner.mdot = mdot
 
 f.set_initial_guess()

interfaces/cython/cantera/examples/onedim/flame_fixed_T.py

@@ -14,7 +14,7 @@ mdot = 0.04  # kg/m^2/s
 comp = 'CH4:0.65, O2:1, N2:3.76'  # premixed gas composition
 
 # The solution domain is chosen to be 1 cm
-initial_grid = np.linspace(0.0, 0.01, 6) # m
+width = 0.01 # m
 
 tol_ss = [1.0e-5, 1.0e-9]  # [rtol atol] for steady-state problem
 tol_ts = [1.0e-5, 1.0e-4]  # [rtol atol] for time stepping
@@ -33,7 +33,7 @@ gas = ct.Solution('gri30.xml', 'gri30_mix')
 gas.TPX = tburner, p, comp
 
 # create the BurnerFlame object.
-f = ct.BurnerFlame(gas=gas, grid=initial_grid)
+f = ct.BurnerFlame(gas=gas, width=width)
 
 # set the mass flow rate at the burner
 f.burner.mdot = mdot

interfaces/cython/cantera/onedim.py

@@ -441,13 +441,18 @@ class BurnerFlame(FlameBase):
     """A burner-stabilized flat flame."""
     __slots__ = ('burner', 'flame', 'outlet')
 
-    def __init__(self, gas, grid=None):
+    def __init__(self, gas, grid=None, width=None):
         """
         :param gas:
             `Solution` (using the IdealGas thermodynamic model) used to
             evaluate all gas properties and reaction rates.
         :param grid:
-            Array of initial grid points
+            A list of points to be used as the initial grid. Not recommended
+            unless solving only on a fixed grid; Use the `width` parameter
+            instead.
+        :param width:
+            Defines a grid on the interval [0, width] with internal points
+            determined automatically by the solver.
 
         A domain of class `AxisymmetricStagnationFlow` named ``flame`` will
         be created to represent the flame. The three domains comprising the
@@ -458,6 +463,9 @@ class BurnerFlame(FlameBase):
         self.outlet = Outlet1D(name='outlet', phase=gas)
         self.flame = AxisymmetricStagnationFlow(gas, name='flame')
 
+        if width is not None:
+            grid = np.array([0.0, 0.1, 0.2, 0.3, 0.5, 0.7, 1.0]) * width
+
         super(BurnerFlame, self).__init__((self.burner, self.flame, self.outlet),
                                           gas, grid)