def test_mixture_averaged(self, saveReference=False):
T_in = 373.0 # inlet temperature
comp = 'H2:1.6, O2:1, AR:7' # premixed gas composition
gas = ct.Solution('h2o2.xml')
gas.TPX = T_in, 0.05 * ct.one_atm, comp
width = 0.2 # m
sim = ct.CounterflowPremixedFlame(gas=gas, width=width)
# set the properties at the inlets
sim.reactants.mdot = 0.12 # kg/m^2/s
sim.reactants.X = comp
sim.reactants.T = T_in
sim.products.mdot = 0.06 # kg/m^2/s
sim.flame.set_steady_tolerances(default=[1.0e-5, 1.0e-11])
sim.flame.set_transient_tolerances(default=[1.0e-5, 1.0e-11])
sim.set_initial_guess() # assume adiabatic equilibrium products
sim.energy_enabled = False
sim.solve(loglevel=0, refine_grid=False)
sim.set_refine_criteria(ratio=3, slope=0.2, curve=0.4, prune=0.02)
sim.energy_enabled = True
self.assertFalse(sim.radiation_enabled)
sim.solve(loglevel=0, refine_grid=True)
data = np.empty((sim.flame.n_points, gas.n_species + 4))
data[:, 0] = sim.grid
data[:, 1] = sim.velocity
data[:, 2] = sim.spread_rate
data[:, 3] = sim.T
data[:, 4:] = sim.Y.T
referenceFile = pjoin(self.test_data_dir,
'CounterflowPremixedFlame-h2-mix.csv')
if saveReference:
np.savetxt(referenceFile, data, '%11.6e', ', ')
else:
bad = utilities.compareProfiles(referenceFile,
data,
rtol=1e-2,
atol=1e-8,
xtol=1e-2)
self.assertFalse(bad, bad)
filename = pjoin(self.test_work_dir,
'CounterflowPremixedFlame-h2-mix.csv')
sim.write_csv(filename) # check output
self.assertTrue(os.path.exists(filename))
csv_data = np.genfromtxt(filename,
dtype=float,
delimiter=',',
names=True)
self.assertNotIn('qdot', csv_data.dtype.names)
os.remove(filename)
def run_case(self, phi, T, width, P):
gas = ct.Solution('h2o2.xml')
gas.TPX = T, P * ct.one_atm, {'H2': phi, 'O2': 0.5, 'AR': 2}
sim = ct.CounterflowPremixedFlame(gas=gas, width=width)
sim.reactants.mdot = 10 * gas.density
sim.products.mdot = 5 * gas.density
sim.set_refine_criteria(ratio=6, slope=0.7, curve=0.8, prune=0.4)
sim.solve(loglevel=0, auto=True)
self.assertTrue(all(sim.T >= T - 1e-3))
self.assertTrue(all(sim.spread_rate >= -1e-9))
return sim
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, width=0.2)
sim.reactants.mdot = 0.12 # kg/m^2/s
sim.products.mdot = 0.06 # kg/m^2/s
sim.set_refine_criteria(ratio=3, slope=0.1, curve=0.2)
sim.solve(0, auto=True)
return sim
def __init__(self,
solution,
chemistry,
fuel,
oxidizer={
'O2': 1.,
'N2': 3.76
},
T=None):
self.chemistry = chemistry
gas = ct.Solution(chemistry, loglevel=0)
flame = ct.CounterflowPremixedFlame(gas, width=0.1)
flame.restore(solution, loglevel=0)
PremixedFlameState.__init__(self, flame, fuel, oxidizer, T)
def test_mixture_averaged(self, saveReference=False):
T_in = 373.0 # inlet temperature
comp = 'H2:1.6, O2:1, AR:7' # premixed gas composition
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
sim = ct.CounterflowPremixedFlame(gas=gas, grid=initial_grid)
# set the properties at the inlets
sim.reactants.mdot = 0.12 # kg/m^2/s
sim.reactants.X = comp
sim.reactants.T = T_in
sim.products.mdot = 0.06 # kg/m^2/s
sim.flame.set_steady_tolerances(default=[1.0e-5, 1.0e-11])
sim.flame.set_transient_tolerances(default=[1.0e-5, 1.0e-11])
sim.set_initial_guess() # assume adiabatic equilibrium products
sim.energy_enabled = False
sim.solve(loglevel=0, refine_grid=False)
sim.set_refine_criteria(ratio=3, slope=0.2, curve=0.4, prune=0.02)
sim.energy_enabled = True
self.assertFalse(sim.radiation_enabled)
sim.solve(loglevel=0, refine_grid=True)
data = np.empty((sim.flame.n_points, gas.n_species + 4))
data[:, 0] = sim.grid
data[:, 1] = sim.u
data[:, 2] = sim.V
data[:, 3] = sim.T
data[:, 4:] = sim.Y.T
if saveReference:
np.savetxt(self.referenceFile, data, '%11.6e', ', ')
else:
bad = utilities.compareProfiles(self.referenceFile,
data,
rtol=1e-2,
atol=1e-8,
xtol=1e-2)
self.assertFalse(bad, bad)
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.reactants.mdot = 0.12 # kg/m^2/s
sim.products.mdot = 0.06 # kg/m^2/s
sim.flame.set_steady_tolerances(default=[1.0e-7, 1.0e-13])
sim.flame.set_transient_tolerances(default=[1.0e-7, 1.0e-11])
sim.set_initial_guess()
sim.energy_enabled = False
sim.solve(0, refine_grid=False)
sim.set_refine_criteria(ratio=3, slope=0.1, curve=0.2)
sim.energy_enabled = True
sim.solve(0, refine_grid=True)
return sim
mdot_reactants = 0.12 # kg/m^2/s
mdot_products = 0.06 # kg/m^2/s
rxnmech = 'h2o2.yaml' # reaction mechanism file
comp = 'H2:1.6, O2:1, AR:7' # premixed gas composition
width = 0.2 # m
loglevel = 1 # amount of diagnostic output (0 to 5)
# Set up the problem
gas = ct.Solution(rxnmech)
# set state to that of the unburned gas at the burner
gas.TPX = T_in, p, comp
# Create the flame simulation object
sim = ct.CounterflowPremixedFlame(gas=gas, width=width)
# Set grid refinement parameters
sim.set_refine_criteria(ratio=3, slope=0.1, curve=0.2, prune=0.02)
# set the boundary flow rates
sim.reactants.mdot = mdot_reactants
sim.products.mdot = mdot_products
sim.set_initial_guess() # assume adiabatic equilibrium products
sim.show_solution()
sim.solve(loglevel, auto=True)
# write the velocity, temperature, and mole fractions to a CSV file
sim.write_csv('premixed_counterflow.csv', quiet=False)
loglevel = 1 # amount of diagnostic output (0 to 5) # Grid refinement parameters ratio = 3 slope = 0.1 curve = 0.2 prune = 0.02 # Set up the problem gas = ct.Solution(rxnmech) # set state to that of the unburned gas at the burner gas.TPX = T_in, p, comp # Create the flame simulation object sim = ct.CounterflowPremixedFlame(gas=gas, grid=initial_grid) # set the properties at the inlet sim.reactants.mdot = mdot_reactants sim.reactants.X = comp sim.reactants.T = T_in sim.products.mdot = mdot_products sim.flame.set_steady_tolerances(default=tol_ss) sim.flame.set_transient_tolerances(default=tol_ts) sim.set_initial_guess() # assume adiabatic equilibrium products sim.show_solution() sim.energy_enabled = False sim.solve(loglevel, False)
def counterflow_premixed_flame_(gas, a=1000., solution=None, **kwargs):
# read kwargs
if 'transport' in kwargs.keys():
transport = kwargs['transport']
else:
transport = 'Mix'
if 'width' in kwargs.keys():
width = kwargs['width']
else:
width = 0.05
if 'loglevel' in kwargs.keys():
loglevel = kwargs['loglevel']
else:
# supress log output
loglevel = 0
# kwargs for flame solver
if 'ct_ratio' in kwargs.keys():
ct_ratio = kwargs['ct_ratio']
else:
ct_ratio = 2.
if 'ct_slope' in kwargs.keys():
ct_slope = kwargs['ct_slope']
else:
ct_slope = 0.2
if 'ct_curve' in kwargs.keys():
ct_curve = kwargs['ct_curve']
else:
ct_curve = 0.2
if 'ct_prune' in kwargs.keys():
ct_prune = kwargs['ct_prune']
else:
ct_prune = 0.1
if 'ct_max_grids' in kwargs.keys():
ct_max_grids = kwargs['ct_max_grids']
else:
ct_max_grids = 5000
# Create flame object
f = ct.CounterflowPremixedFlame(gas=gas, width=width)
# unburnt stream
rho_u = gas.density
# burnt stream
gas.equilibrate('HP')
rho_b = gas.density
# get inlet velocity based on the strain rate
# $a_1=\dfrac{2U_1}{L}\left(1+\dfrac{U_2\sqrt{\rho_2}}{U_1\sqrt{\rho_1}}\right)$
# $a_2=\dfrac{2U_2}{L}\left(1+\dfrac{U_1\sqrt{\rho_1}}{U_2\sqrt{\rho_2}}\right)$
# with $\rho_1 U_1^2 = \rho_2 U_2^2$
# $a_1=\dfrac{4U_1}{L}$ $a_2=\dfrac{4U_2}{L}$
# set stream 1 and 2 for unburnt and equilibrium status respectively
v_u = a * width / 4.0
v_b = np.sqrt(rho_u * np.square(v_u) / rho_b)
# mass rate
m_u = rho_u * v_u
m_b = rho_b * v_b
f.transport_model = transport
f.P = gas.P
f.reactants.mdot = m_u
f.products.mdot = m_b
f.set_refine_criteria(ratio=ct_ratio,
slope=ct_slope,
curve=ct_curve,
prune=ct_prune)
f.set_max_grid_points(f.flame, ct_max_grids)
# load saved case if presented
if solution is not None:
f.restore(solution, loglevel=loglevel)
# scaling of saved solution
solution_width = f.grid[-1] - f.grid[0]
width_factor = width / solution_width
solution_a = 4. * f.u[0] / solution_width
a_factor = a / solution_a
normalized_grid = f.grid / solution_width
u_factor = a_factor * width_factor
# update solution initialization following Fiala & Sattelmayer
f.flame.grid = normalized_grid * width
f.set_profile('u', normalized_grid, f.u * u_factor)
f.set_profile('V', normalized_grid, f.V * a_factor)
f.set_profile('lambda', normalized_grid, f.L * np.square(a_factor))
f.reactants.mdot = m_u
f.products.mdot = m_b
else:
f.set_initial_guess()
f.solve(loglevel=loglevel, auto=True)
return f
def counterflow_premixed_flame(chemistry='gri30.xml',
fuel={'CH4': 1.},
oxidizer={
'O2': 1,
'N2': 3.76
},
temperature=300.,
pressure=1.,
phi=1.,
a=1000.,
solution=None,
**kwargs):
# for unrealistic parameters
if pressure < 0.:
raise ValueError('Negative pressure')
if temperature < 0.:
raise ValueError('Negative inlet temperature')
if phi < 0.:
raise ValueError('Negative equivalence ratio')
# read kwargs
if 'transport' in kwargs.keys():
transport = kwargs['transport']
else:
transport = 'Mix'
if 'width' in kwargs.keys():
width = kwargs['width']
else:
width = 0.05
if 'loglevel' in kwargs.keys():
loglevel = kwargs['loglevel']
else:
# supress log output
loglevel = 0
# kwargs for flame solver
if 'ct_ratio' in kwargs.keys():
ct_ratio = kwargs['ct_ratio']
else:
ct_ratio = 2.
if 'ct_slope' in kwargs.keys():
ct_slope = kwargs['ct_slope']
else:
ct_slope = 0.02
if 'ct_curve' in kwargs.keys():
ct_curve = kwargs['ct_curve']
else:
ct_curve = 0.02
if 'ct_prune' in kwargs.keys():
ct_prune = kwargs['ct_prune']
else:
ct_prune = 0.01
if 'ct_max_grids' in kwargs.keys():
ct_max_grids = kwargs['ct_max_grids']
else:
ct_max_grids = 5000
# case name
params = {}
params['T'] = temperature
params['p'] = pressure
params['phi'] = phi
params['a'] = a
case = params2name(params)
# pressure
pressure *= ct.one_atm
# gas object
#gas = ct.Solution(chemistry)
# construct mixutre
#mixture = cg.mixture_two_streams(gas, fuel, oxidizer, phi)
# unburnt stream
#gas.TPX = temperature, pressure, mixture
gas = cg.mixture(chemistry, fuel, oxidizer, temperature, pressure, phi)
rho_u = gas.density
# burnt stream
gas.equilibrate('HP')
rho_b = gas.density
gas = cg.mixture(chemistry, fuel, oxidizer, temperature, pressure, phi)
# get inlet velocity based on the strain rate
# $a_1=\dfrac{2U_1}{L}\left(1+\dfrac{U_2\sqrt{\rho_2}}{U_1\sqrt{\rho_1}}\right)$
# $a_2=\dfrac{2U_2}{L}\left(1+\dfrac{U_1\sqrt{\rho_1}}{U_2\sqrt{\rho_2}}\right)$
# with $\rho_1 U_1^2 = \rho_2 U_2^2$
# $a_1=\dfrac{4U_1}{L}$ $a_2=\dfrac{4U_2}{L}$
# set stream 1 and 2 for unburnt and equilibrium status respectively
v_u = a * width / 4.0
v_b = np.sqrt(rho_u * np.square(v_u) / rho_b)
# mass rate
m_u = rho_u * v_u
m_b = rho_b * v_b
# Create flame object
f = ct.CounterflowPremixedFlame(gas=gas, width=width)
f.transport_model = transport
f.P = pressure
f.reactants.mdot = m_u
f.products.mdot = m_b
f.set_refine_criteria(ratio=ct_ratio,
slope=ct_slope,
curve=ct_curve,
prune=ct_prune)
f.set_max_grid_points(f.flame, ct_max_grids)
# load saved case if presented
if solution is not None:
f.restore(solution, loglevel=loglevel)
# scaling of saved solution
solution_width = f.grid[-1] - f.grid[0]
width_factor = width / solution_width
solution_a = 4. * f.u[0] / solution_width
a_factor = a / solution_a
normalized_grid = f.grid / solution_width
u_factor = a_factor * width_factor
# update solution initialization following Fiala & Sattelmayer
f.flame.grid = normalized_grid * width
f.set_profile('u', normalized_grid, f.u * u_factor)
f.set_profile('V', normalized_grid, f.V * a_factor)
f.set_profile('lambda', normalized_grid, f.L * np.square(a_factor))
f.reactants.mdot = m_u
f.products.mdot = m_b
else:
f.set_initial_guess()
f.solve(loglevel=loglevel, auto=True)
HRR = f.heat_release_rate
idx = HRR.argmax()
if HRR[idx] > 1000:
f.save('{}.xml'.format(case))
if f.u[idx] > 0:
return 0
else:
return 2
else:
return 1
