# Twin Premixed Counter-Flow Flame¶

This example documents how to simulate two identical, axisymmetric, premixed jets of reactants shooting into each other.

An illustration of this configuration is shown in the figure below.

### Import modules¶

In [1]:
import cantera as ct
import numpy as np

print(f"Running Cantera Version: {ct.__version__}")

Running Cantera Version: 2.6.0a4

In [2]:
%matplotlib inline
%config InlineBackend.figure_formats = ["svg"]
import matplotlib.pyplot as plt

plt.rcParams["figure.autolayout"] = True

plt.rcParams["axes.labelsize"] = 14
plt.rcParams["xtick.labelsize"] = 12
plt.rcParams["ytick.labelsize"] = 12
plt.rcParams["legend.fontsize"] = 10
plt.rcParams["figure.facecolor"] = "white"
plt.rcParams["figure.figsize"] = (8, 6)
plt.rcParams["figure.dpi"] = 120


### Define the reactant conditions, gas mixture and kinetic mechanism associated with the gas¶

In [3]:
# Inlet Temperature in Kelvin and Inlet Pressure in Pascals
# In this case we are setting the inlet T and P to room temperature conditions
To = 300
Po = 101325

# Define the gas-mixutre and kinetics
# In this case, we are choosing a GRI3.0 gas
gas = ct.Solution("gri30.yaml")

# Create a CH4/Air premixed mixture with equivalence ratio=0.75
gas.set_equivalence_ratio(0.75, "CH4", {"O2": 1.0, "N2": 3.76})
gas.TP = To, Po

# Set the velocity of the reactants
# This is what determines the strain-rate
axial_velocity = 2.0  # in m/s

# Done with initial conditions
# Compute the mass flux, as this is what the Flame object requires
mass_flux = gas.density * axial_velocity  # units kg/m2/s


### Define functions¶

In [4]:
def derivative(x, y):
"""Differentiation function for data that has variable grid spacing.
Used here to compute normal strain-rate.
"""
dydx = np.zeros_like(y)

dx = np.diff(x)
dy = np.diff(y)
dydx[0:-1] = dy / dx

dydx[-1] = (y[-1] - y[-2]) / (x[-1] - x[-2])

return dydx

def compute_strain_rates(opposed_flame):
# Compute the derivative of axial velocity to obtain normal strain rate
strain_rates = derivative(opposed_flame.grid, opposed_flame.velocity)

# Obtain the location of the max. strain rate upstream of the pre-heat zone.
# This is the characteristic strain rate
max_strain_location = abs(strain_rates).argmax()
min_velocity_point = opposed_flame.velocity[:max_strain_location].argmin()

# Characteristic Strain Rate = K
strain_rate_point = abs(strain_rates[:min_velocity_point]).argmax()
K = abs(strain_rates[strain_rate_point])

return strain_rates, strain_rate_point, K

def compute_consumption_speed(opposed_flame):

Tb = max(opposed_flame.T)
Tu = min(opposed_flame.T)
rho_u = max(opposed_flame.density)

integrand = opposed_flame.heat_release_rate / opposed_flame.cp

I = np.trapz(integrand, opposed_flame.grid)
Sc = I / (Tb - Tu) / rho_u

return Sc

# This function is called to run the solver
def solve_opposed_flame(
opposed_flame, mass_flux=0.12, loglevel=0, ratio=2, slope=0.3, curve=0.3, prune=0.05
):
"""
Execute this function to run the Oppposed Flow Simulation This function
takes a CounterFlowTwinPremixedFlame object as the first argument
"""

opposed_flame.reactants.mdot = mass_flux
opposed_flame.set_refine_criteria(
ratio=ratio, slope=slope, curve=curve, prune=prune
)

opposed_flame.show_solution()
opposed_flame.solve(loglevel, auto=True)

# Compute the strain rate, just before the flame. This is not necessarily
# the maximum We use the max. strain rate just upstream of the pre-heat zone
# as this is the strain rate that computations comprare against, like when
# plotting Su vs. K
_, strain_rate_point, K = compute_strain_rates(opposed_flame)

return np.max(opposed_flame.T), K, strain_rate_point


### Define a flame object, domain width and tranport model¶

In [5]:
# Define a domain half-width of 2.5 cm, meaning the whole domain is 5 cm wide
width = 0.025

# Create the flame object
opposed_flame = ct.CounterflowTwinPremixedFlame(gas, width=width)

# Uncomment the following line to use a Multi-component formulation. Default is
# mixture-averaged
# opposed_flame.transport_model = 'Multi'


### Run the Solver¶

In [6]:
# The solver returns the peak temperature, strain rate and
# the point which we ascribe to the characteristic strain rate.

T, K, strain_rate_point = solve_opposed_flame(opposed_flame, mass_flux, loglevel=1)

# You can plot/see all state space variables by calling opposed_flame.foo where foo
# is T, Y[i], etc. The spatial variable (distance in meters) is in opposed_flame.grid
# Thus to plot temperature vs distance, use opposed_flame.grid and opposed_flame.T

# Uncomment this to save output
# opposed_flame.write_csv("premixed_twin_flame.csv", quiet=False)


>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> reactants <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

Mass Flux:        2.268 kg/m^2/s
Temperature:        300 K
Mass Fractions:
O2      0.2232
CH4     0.04197
N2      0.7348

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> flame <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

Pressure:   1.013e+05 Pa

-------------------------------------------------------------------------------
z    velocity  spread_rate           T      lambda      eField
-------------------------------------------------------------------------------
0           2           0         300  -2.903e+04           0
0.005         1.6          32         300  -2.903e+04           0
0.01         1.2          64         300  -2.903e+04           0
0.0125           1          80        1110  -2.903e+04           0
0.015         0.8          96        1920  -2.903e+04           0
0.02         0.4         128        1920  -2.903e+04           0
0.025           0         160        1920  -2.903e+04           0

-------------------------------------------------------------------------------
z          H2           H           O          O2          OH
-------------------------------------------------------------------------------
0           0           0           0      0.2232           0
0.005           0           0           0      0.2232           0
0.01    2.06e-21   9.355e-23   1.216e-20      0.2232   1.907e-19
0.0125   3.711e-06   1.685e-07   2.191e-05      0.1386   0.0003435
0.015   7.423e-06    3.37e-07   4.382e-05     0.05402   0.0006871
0.02   7.423e-06    3.37e-07   4.382e-05     0.05402   0.0006871
0.025   7.423e-06    3.37e-07   4.382e-05     0.05402   0.0006871

-------------------------------------------------------------------------------
z         H2O         HO2        H2O2           C          CH
-------------------------------------------------------------------------------
0           0           0           0           0           0
0.005           0           0           0           0           0
0.01   2.604e-17   2.619e-22   1.513e-23   1.528e-38   1.236e-39
0.0125     0.04691   4.717e-07   2.725e-08   2.753e-23   2.226e-24
0.015     0.09382   9.435e-07    5.45e-08   5.506e-23   4.452e-24
0.02     0.09382   9.435e-07    5.45e-08   5.506e-23   4.452e-24
0.025     0.09382   9.435e-07    5.45e-08   5.506e-23   4.452e-24

-------------------------------------------------------------------------------
z         CH2      CH2(S)         CH3         CH4          CO
-------------------------------------------------------------------------------
0           0           0           0     0.04197           0
0.005           0           0           0     0.04197           0
0.01   4.048e-39   1.788e-40   3.885e-38     0.04197   6.135e-20
0.0125   7.292e-24    3.22e-25   6.999e-23     0.02098   0.0001105
0.015   1.458e-23   6.441e-25     1.4e-22           0    0.000221
0.02   1.458e-23   6.441e-25     1.4e-22   8.264e-23    0.000221
0.025   1.458e-23   6.441e-25     1.4e-22   8.264e-23    0.000221

-------------------------------------------------------------------------------
z         CO2         HCO        CH2O       CH2OH        CH3O
-------------------------------------------------------------------------------
0           0           0           0           0           0
0.005           0           0           0           0           0
0.01   3.186e-17   2.588e-28   2.804e-30    6.75e-37   8.315e-39
0.0125     0.05739   4.662e-13   5.052e-15   1.216e-21   1.498e-23
0.015      0.1148   9.324e-13    1.01e-14   2.432e-21   2.996e-23
0.02      0.1148   9.324e-13    1.01e-14   2.432e-21   2.996e-23
0.025      0.1148   9.324e-13    1.01e-14   2.432e-21   2.996e-23

-------------------------------------------------------------------------------
z       CH3OH         C2H        C2H2        C2H3        C2H4
-------------------------------------------------------------------------------
0           0           0           0           0           0
0.005           0           0           0           0           0
0.01   5.227e-38   9.354e-48   7.624e-45   5.836e-51   9.138e-51
0.0125   9.416e-23   1.685e-32   1.373e-29   1.051e-35   1.646e-35
0.015   1.883e-22    3.37e-32   2.747e-29   2.103e-35   3.292e-35
0.02   1.883e-22    3.37e-32   2.747e-29   2.103e-35   3.292e-35
0.025   1.883e-22    3.37e-32   2.747e-29   2.103e-35   3.292e-35

-------------------------------------------------------------------------------
z        C2H5        C2H6        HCCO       CH2CO       HCCOH
-------------------------------------------------------------------------------
0           0           0           0           0           0
0.005           0           0           0           0           0
0.01   1.002e-56   7.332e-58     2.1e-41   3.353e-41    1.05e-44
0.0125   1.805e-41   1.321e-42   3.783e-26    6.04e-26   1.892e-29
0.015    3.61e-41   2.641e-42   7.566e-26   1.208e-25   3.784e-29
0.02    3.61e-41   2.641e-42   7.566e-26   1.208e-25   3.784e-29
0.025    3.61e-41   2.641e-42   7.566e-26   1.208e-25   3.784e-29

-------------------------------------------------------------------------------
z           N          NH         NH2         NH3         NNH
-------------------------------------------------------------------------------
0           0           0           0           0           0
0.005           0           0           0           0           0
0.01   3.232e-26   2.797e-27   8.652e-28   3.559e-27   4.476e-27
0.0125   5.822e-11   5.038e-12   1.559e-12   6.411e-12   8.063e-12
0.015   1.164e-10   1.008e-11   3.117e-12   1.282e-11   1.613e-11
0.02   1.164e-10   1.008e-11   3.117e-12   1.282e-11   1.613e-11
0.025   1.164e-10   1.008e-11   3.117e-12   1.282e-11   1.613e-11

-------------------------------------------------------------------------------
z          NO         NO2         N2O         HNO          CN
-------------------------------------------------------------------------------
0           0           0           0           0           0
0.005           0           0           0           0           0
0.01   8.318e-19   1.205e-21   6.697e-23   2.279e-24   1.185e-33
0.0125    0.001498    2.17e-06   1.206e-07   4.106e-09   2.135e-18
0.015    0.002997   4.341e-06   2.413e-07   8.212e-09    4.27e-18
0.02    0.002997   4.341e-06   2.413e-07   8.212e-09    4.27e-18
0.025    0.002997   4.341e-06   2.413e-07   8.212e-09    4.27e-18

-------------------------------------------------------------------------------
z         HCN        H2CN        HCNN        HCNO        HOCN
-------------------------------------------------------------------------------
0           0           0           0           0           0
0.005           0           0           0           0           0
0.01   8.215e-31   1.546e-38   4.735e-42   1.504e-35   8.599e-31
0.0125    1.48e-15   2.785e-23    8.53e-27    2.71e-20   1.549e-15
0.015    2.96e-15    5.57e-23   1.706e-26    5.42e-20   3.098e-15
0.02    2.96e-15    5.57e-23   1.706e-26    5.42e-20   3.098e-15
0.025    2.96e-15    5.57e-23   1.706e-26    5.42e-20   3.098e-15

-------------------------------------------------------------------------------
z        HNCO         NCO          N2          AR        C3H7
-------------------------------------------------------------------------------
0           0           0      0.7348           0           0
0.005           0           0      0.7348           0           0
0.01    7.04e-28   1.842e-29      0.7348           0   6.242e-76
0.0125   1.268e-12   3.319e-14      0.7341           0   1.125e-60
0.015   2.536e-12   6.638e-14      0.7334           0   2.249e-60
0.02   2.536e-12   6.638e-14      0.7334           0   2.249e-60
0.025   2.536e-12   6.638e-14      0.7334           0   2.249e-60

-------------------------------------------------------------------------------
z        C3H8      CH2CHO      CH3CHO
-------------------------------------------------------------------------------
0           0           0           0
0.005           0           0           0
0.01   4.325e-77   1.343e-47   2.414e-48
0.0125   7.791e-62    2.42e-32   4.349e-33
0.015   1.558e-61    4.84e-32   8.697e-33
0.02   1.558e-61    4.84e-32   8.697e-33
0.025   1.558e-61    4.84e-32   8.697e-33

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> products <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

-------------------------------------------------------------------------------
z
-------------------------------------------------------------------------------
0

************ Solving on 7 point grid with energy equation enabled ************

..............................................................................
Attempt Newton solution of steady-state problem...    failure.
Take 10 timesteps     2.848e-05      5.886
Attempt Newton solution of steady-state problem...    failure.
Take 10 timesteps     0.0004865      5.141
Attempt Newton solution of steady-state problem...    failure.
Take 10 timesteps      0.008313      2.219
Attempt Newton solution of steady-state problem...    success.

Problem solved on [7] point grid(s).

..............................................................................
grid refinement disabled.

******************** Solving with grid refinement enabled ********************

..............................................................................
Attempt Newton solution of steady-state problem...    success.

Problem solved on [7] point grid(s).

..............................................................................
##############################################################################
Refining grid in flame.
New points inserted after grid points 1 2 3 4 5
to resolve C2H2 C2H4 C2H6 CH CH2 CH2(S) CH2CO CH2O CH2OH CH3 CH3CHO CH3O CH3OH CH4 CO CO2 H H2 H2O H2O2 HCCO HCN HCO HNCO HO2 N2 N2O NO NO2 O O2 OH T point 1 point 4 spread_rate velocity
##############################################################################

..............................................................................
Attempt Newton solution of steady-state problem...    failure.
Take 10 timesteps     0.0001139      5.733
Attempt Newton solution of steady-state problem...    failure.
Take 10 timesteps      0.002919      3.554
Attempt Newton solution of steady-state problem...    success.

Problem solved on [12] point grid(s).

..............................................................................
##############################################################################
Refining grid in flame.
New points inserted after grid points 2 4 5 6 7 8 9 10
to resolve C C2H2 C2H3 C2H4 C2H5 C2H6 C3H8 CH CH2 CH2(S) CH2CO CH2O CH2OH CH3 CH3CHO CH3O CH3OH CH4 CO CO2 H H2 H2O H2O2 HCCO HCN HCO HNCO HO2 N2 N2O NO NO2 O O2 OH T point 2 point 7 spread_rate velocity
##############################################################################

..............................................................................
Attempt Newton solution of steady-state problem...    failure.
Take 10 timesteps     0.0001139      5.652
Attempt Newton solution of steady-state problem...    failure.
Take 10 timesteps     0.0001442      5.842
Attempt Newton solution of steady-state problem...    failure.
Take 10 timesteps      0.002463      3.921
Attempt Newton solution of steady-state problem...    success.

Problem solved on [20] point grid(s).

..............................................................................
##############################################################################
Refining grid in flame.
New points inserted after grid points 1 4 9 10 11 12 13 17 18
to resolve C C2H2 C2H3 C2H4 C2H6 CH CH2 CH2(S) CH2CO CH2O CH2OH CH3 CH3CHO CH3O CH3OH CH4 CO CO2 H H2 H2O H2O2 HCCO HCN HCO HNCO HO2 N2 N2O NO NO2 O O2 OH T point 1 point 4 spread_rate velocity
##############################################################################

..............................................................................
Attempt Newton solution of steady-state problem...    failure.
Take 10 timesteps     0.0001139      5.646
Attempt Newton solution of steady-state problem...    success.

Problem solved on [29] point grid(s).

..............................................................................
##############################################################################
Refining grid in flame.
New points inserted after grid points 0 10 14 15 16 17 18 23 26 27
to resolve C C2H2 C2H3 C2H4 C2H5 C2H6 C3H8 CH CH2 CH2(S) CH2CHO CH2CO CH2O CH2OH CH3 CH3CHO CH3O CH3OH CH4 CO CO2 H H2 H2O H2O2 HCCO HCN HCO HNCO HO2 N2 N2O NO NO2 O O2 OH T point 0 point 10 point 23 spread_rate velocity
##############################################################################

..............................................................................
Attempt Newton solution of steady-state problem...    failure.
Take 10 timesteps     7.594e-05       6.15
Attempt Newton solution of steady-state problem...    failure.
Take 10 timesteps     7.208e-05      6.136
Attempt Newton solution of steady-state problem...    failure.
Take 10 timesteps     0.0001368      5.859
Attempt Newton solution of steady-state problem...    failure.
Take 10 timesteps     0.0001299      5.765
Attempt Newton solution of steady-state problem...    failure.
Take 10 timesteps      0.002219      3.793
Attempt Newton solution of steady-state problem...    success.

Problem solved on [39] point grid(s).

..............................................................................
##############################################################################
Refining grid in flame.
New points inserted after grid points 24 25 26 27 28 36 37
to resolve C C2H2 C2H3 C2H4 C2H5 C2H6 C3H8 CH CH2 CH2(S) CH2CO CH2O CH2OH CH3 CH3CHO CH3O CH3OH CH4 CO CO2 H H2 H2O H2O2 HCCO HCN HCO HNCO HO2 N2 N2O NO NO2 O O2 OH T spread_rate velocity
##############################################################################

..............................................................................
Attempt Newton solution of steady-state problem...    failure.
Take 10 timesteps     5.695e-05      5.871
Attempt Newton solution of steady-state problem...    failure.
Take 10 timesteps     7.208e-05      6.079
Attempt Newton solution of steady-state problem...    failure.
Take 10 timesteps     3.849e-05      5.896
Attempt Newton solution of steady-state problem...    failure.
Take 10 timesteps     0.0002923      5.341
Attempt Newton solution of steady-state problem...    success.

Problem solved on [45] point grid(s).

..............................................................................
##############################################################################
Refining grid in flame.
New points inserted after grid points 28 29 30 31 32 33
to resolve C C2H2 C2H3 C2H4 C2H5 C2H6 C3H8 CH CH2 CH2(S) CH2CHO CH2CO CH2O CH2OH CH3 CH3CHO CH3O CH3OH CH4 CO CO2 H H2 H2O H2O2 HCCO HCN HCO HNCO HO2 N2 N2O NO NO2 O O2 OH T spread_rate velocity
##############################################################################

..............................................................................
Attempt Newton solution of steady-state problem...    failure.
Take 10 timesteps     0.0001709      5.407
Attempt Newton solution of steady-state problem...    success.

Problem solved on [49] point grid(s).

..............................................................................
##############################################################################
Refining grid in flame.
New points inserted after grid points 30 31 32 33 34 35 36
to resolve C C2H2 C2H3 C2H4 C2H5 C2H6 C3H7 C3H8 CH CH2 CH2(S) CH2CHO CH2CO CH2O CH2OH CH3 CH3CHO CH3O CH3OH CH4 CO CO2 H H2 H2O H2O2 HCCO HCCOH HCN HCO HNCO HO2 N2 N2O NO NO2 O O2 OH T spread_rate velocity
##############################################################################

..............................................................................
Attempt Newton solution of steady-state problem...    failure.
Take 10 timesteps     0.0001139       5.78
Attempt Newton solution of steady-state problem...    failure.
Take 10 timesteps     0.0005767      5.352
Attempt Newton solution of steady-state problem...    failure.
Take 10 timesteps     0.0003079      5.432
Attempt Newton solution of steady-state problem...    success.

Problem solved on [56] point grid(s).

..............................................................................
##############################################################################
Refining grid in flame.
New points inserted after grid points 29 34 39 40 41 42 43 44
to resolve C C2H2 C2H3 C2H4 C2H5 C2H6 C3H7 C3H8 CH CH2 CH2(S) CH2CHO CH2CO CH2O CH2OH CH3 CH3CHO CH3O CH3OH CH4 CO CO2 H H2 H2O H2O2 HCCO HCCOH HCN HCNO HCO HNCO HO2 N2 N2O NO NO2 O O2 OH T point 29 point 34 velocity
##############################################################################

..............................................................................
Attempt Newton solution of steady-state problem...    failure.
Take 10 timesteps     0.0001709      5.602
Attempt Newton solution of steady-state problem...    failure.
Take 10 timesteps      0.001297      4.468
Attempt Newton solution of steady-state problem...    success.

Problem solved on [63] point grid(s).

..............................................................................
##############################################################################
Refining grid in flame.
New points inserted after grid points 45 46 47 48 49 50 51 52
to resolve C2H2 C2H3 C2H4 C2H5 C2H6 C3H7 C3H8 CH CH2 CH2(S) CH2CHO CH2CO CH2O CH2OH CH3 CH3CHO CH3O CH3OH CH4 CO CO2 H H2 H2O H2O2 HCCO HCCOH HCN HCO HNCO HO2 N2 NO NO2 O O2 OH T point 46 velocity
##############################################################################

..............................................................................
Attempt Newton solution of steady-state problem...    failure.
Take 10 timesteps     0.0002563      5.242
Attempt Newton solution of steady-state problem...    failure.
Take 10 timesteps      0.001946      4.415
Attempt Newton solution of steady-state problem...    success.

Problem solved on [69] point grid(s).

..............................................................................
##############################################################################
Refining grid in flame.
New points inserted after grid points 42 50 51 52 53 54 55 56 57
to resolve C2H2 C2H3 C2H4 C2H5 C2H6 C3H7 C3H8 CH CH2 CH2(S) CH2CHO CH2CO CH2O CH2OH CH3 CH3CHO CH3O CH3OH CH4 CO CO2 H H2 H2O H2O2 HCCO HCCOH HCN HCO HNCO HO2 N2 NO2 O O2 OH T point 42 point 53 velocity
##############################################################################

..............................................................................
Attempt Newton solution of steady-state problem...    success.

Problem solved on [74] point grid(s).

..............................................................................
##############################################################################
Refining grid in flame.
New points inserted after grid points 52 53 54 55 56 57 58 59 60 61
to resolve C2H2 C2H3 C2H4 C2H5 C2H6 C3H7 C3H8 CH CH2 CH2(S) CH2CHO CH2CO CH2O CH2OH CH3 CH3CHO CH3O CH3OH CH4 CO H H2 H2O H2O2 HCCO HCCOH HCN HCO HNCO HO2 N2 NO2 O O2 OH T point 61
##############################################################################

..............................................................................
Attempt Newton solution of steady-state problem...    success.

Problem solved on [82] point grid(s).

..............................................................................
##############################################################################
Refining grid in flame.
New points inserted after grid points 49 50 54 55 56 57 58 59 60 61
to resolve C2H2 C2H3 C2H4 C2H5 C2H6 C3H8 CH CH2 CH2(S) CH2CO CH2OH CH3 CH3CHO CH3O HCCO HCO
##############################################################################

..............................................................................
Attempt Newton solution of steady-state problem...    success.

Problem solved on [91] point grid(s).

..............................................................................
##############################################################################
Refining grid in flame.
New points inserted after grid points 43 45 46 49 53 54 55
to resolve C2H5 C2H6 C3H8 CH3O point 49
##############################################################################

..............................................................................
Attempt Newton solution of steady-state problem...    success.

Problem solved on [98] point grid(s).

..............................................................................
##############################################################################
Refining grid in flame.
New points inserted after grid points 50 51 60
to resolve CH3O point 60
##############################################################################

..............................................................................
Attempt Newton solution of steady-state problem...    success.

Problem solved on [101] point grid(s).

..............................................................................
##############################################################################
Refining grid in flame.
New points inserted after grid points 51
to resolve point 51
##############################################################################

..............................................................................
Attempt Newton solution of steady-state problem...    success.

Problem solved on [102] point grid(s).

..............................................................................
no new points needed in flame

In [7]:
Sc = compute_consumption_speed(opposed_flame)

print(f"Peak temperature: {T:.1f} K")
print(f"Strain Rate: {K:.1f} 1/s")
print(f"Consumption Speed: {Sc * 100:.2f} cm/s")

Peak temperature: 1920.9 K
Strain Rate: 163.7 1/s
Consumption Speed: 21.00 cm/s


### Plot figures¶

Note that the graphs only represent one-half of the domain, because the solution is symmetric

#### Axial velocity plot¶

In [8]:
plt.figure()

plt.plot(opposed_flame.grid * 100, opposed_flame.velocity, "r-o", lw=2)
plt.xlim(opposed_flame.grid[0] * 100, opposed_flame.grid[-1] * 100)
plt.xlabel("Distance (cm)")
plt.ylabel("Axial Velocity (m/s)")

# Identify the point where the strain rate is calculated
plt.plot(
opposed_flame.grid[strain_rate_point] * 100,
opposed_flame.velocity[strain_rate_point],
"gs",
)
plt.annotate(
"Strain-Rate point",
xy=(
opposed_flame.grid[strain_rate_point] * 100,
opposed_flame.velocity[strain_rate_point],
),
xytext=(0.001, 0.1),
arrowprops={"arrowstyle": "->"},
);


#### Temperature Plot¶

In [9]:
plt.figure()

plt.plot(opposed_flame.grid * 100, opposed_flame.T, "b-s", lw=2)
plt.xlim(opposed_flame.grid[0] * 100, opposed_flame.grid[-1] * 100)
plt.xlabel("Distance (cm)")
plt.ylabel("Temperature (K)");


#### Major Species' Plot¶

To plot species, we first have to identify the index of the species in the array. For this, cut & paste the following lines and run in a new cell to get the index

for i, specie in enumerate(gas.species()):
print(f"{i}. {specie}")

In [10]:
# Extract concentration data
X_CH4 = opposed_flame.X[13]
X_CO2 = opposed_flame.X[15]
X_H2O = opposed_flame.X[5]

plt.figure()

plt.plot(opposed_flame.grid * 100, X_CH4, "c-o", lw=2, label="$CH_{4}$")
plt.plot(opposed_flame.grid * 100, X_CO2, "m-s", lw=2, label="$CO_{2}$")
plt.plot(opposed_flame.grid * 100, X_H2O, "g-<", lw=2, label="$H_{2}O$")

plt.xlim(opposed_flame.grid[0] * 100, opposed_flame.grid[-1] * 100)
plt.xlabel("Distance (cm)")
plt.ylabel("Mole Fractions")

plt.legend(loc=2);