[1D] Better initial grid for CounterflowPremixedFlame

Cantera · Mar 25, 2016 · f0a1e25 · f0a1e25
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commit f0a1e25
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Showing 6 changed files with 96 additions and 77 deletions.
diff --git a/doc/sphinx/cython/onedim.rst b/doc/sphinx/cython/onedim.rst
@@ -25,7 +25,7 @@ CounterflowDiffusionFlame
 
 CounterflowPremixedFlame
 ^^^^^^^^^^^^^^^^^^^^^^^^
-.. autoclass:: CounterflowPremixedFlame(gas, grid=None)
+.. autoclass:: CounterflowPremixedFlame(gas, grid=None, width=None)
 
 ImpingingJet
 ^^^^^^^^^^^^

diff --git a/interfaces/cython/cantera/examples/kinetics/extract_submechanism.py b/interfaces/cython/cantera/examples/kinetics/extract_submechanism.py
@@ -58,7 +58,7 @@ def solve_flame(gas):
     gas.TPX = 373, 0.05*ct.one_atm, 'H2:0.4, CO:0.6, O2:1, N2:3.76'
 
     # Create the flame simulation object
-    sim = ct.CounterflowPremixedFlame(gas=gas, grid=np.linspace(0.0, 0.2, 10))
+    sim = ct.CounterflowPremixedFlame(gas=gas, width=0.2)
 
     sim.reactants.mdot = 0.12 # kg/m^2/s
     sim.products.mdot = 0.06 # kg/m^2/s

diff --git a/interfaces/cython/cantera/examples/onedim/premixed_counterflow_flame.py b/interfaces/cython/cantera/examples/onedim/premixed_counterflow_flame.py
@@ -17,7 +17,7 @@
 rxnmech = 'h2o2.cti'  # reaction mechanism file
 comp = 'H2:1.6, O2:1, AR:7'  # premixed gas composition
 
-initial_grid = np.linspace(0.0, 0.2, 12)  # m
+width = 0.2 # m
 tol_ss = [1.0e-7, 1.0e-13]  # [rtol atol] for steady-state problem
 tol_ts = [1.0e-7, 1.0e-11]  # [rtol atol] for time stepping
 loglevel = 1  # amount of diagnostic output (0 to 5)
@@ -35,7 +35,7 @@
 gas.TPX = T_in, p, comp
 
 # Create the flame simulation object
-sim = ct.CounterflowPremixedFlame(gas=gas, grid=initial_grid)
+sim = ct.CounterflowPremixedFlame(gas=gas, width=width)
 
 # set the boundary flow rates
 sim.reactants.mdot = mdot_reactants

diff --git a/interfaces/cython/cantera/onedim.py b/interfaces/cython/cantera/onedim.py
@@ -834,13 +834,17 @@ class CounterflowPremixedFlame(FlameBase):
     """ A premixed counterflow flame """
     __slots__ = ('reactants', 'flame', 'products')
 
-    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
+            Array of initial grid points. 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
@@ -855,6 +859,10 @@ def __init__(self, gas, grid=None):
 
         self.flame = AxisymmetricStagnationFlow(gas, name='flame')
 
+        if width is not None:
+            # Create grid points aligned with initial guess profile
+            grid = np.array([0.0, 0.3, 0.5, 0.7, 1.0]) * width
+
         super(CounterflowPremixedFlame, self).__init__(
                 (self.reactants, self.flame, self.products), gas, grid)
 

diff --git a/interfaces/cython/cantera/test/test_onedim.py b/interfaces/cython/cantera/test/test_onedim.py
@@ -533,9 +533,9 @@ def test_mixture_averaged(self, saveReference=False):
 
         gas = ct.Solution('h2o2.xml')
         gas.TPX = T_in, 0.05 * ct.one_atm, comp
-        initial_grid = np.linspace(0.0, 0.2, 12)  # m
+        width = 0.2 # m
 
-        sim = ct.CounterflowPremixedFlame(gas=gas, grid=initial_grid)
+        sim = ct.CounterflowPremixedFlame(gas=gas, width=width)
 
         # set the properties at the inlets
         sim.reactants.mdot = 0.12  # kg/m^2/s