Modeling Species Transport and Gaseous Combustion#

Introduction#

This tutorial examines the mixing of chemical species and the combustion of a gaseous fuel.

A cylindrical combustor burning methane (\(CH_4\)) in air is studied using the eddy-dissipation model in PyFluent.

This tutorial demonstrates how to do the following:

  • Enable physical models, select material properties, and define boundary conditions for a turbulent flow with chemical species mixing and reaction.

  • Initiate and solve the combustion simulation using the pressure-based solver.

  • Examine the reacting flow results using graphics.

Problem Description#

The cylindrical combustor considered in this tutorial is shown in the following figure. The flame considered is a turbulent diffusion flame. A small nozzle in the center of the combustor introduces methane at 80 m/s. Ambient air enters the combustor coaxially at 0.5 m/s. The overall equivalence ratio is approximately 0.76 (approximately 28% excess air). The high-speed methane jet initially expands with little interference from the outer wall, and entrains and mixes with the low-speed air. The Reynolds number based on the methane jet diameter is approximately \(5.7 × 10^3\).

../../_images/setup.png

Combustion of Methane Gas in a Turbulent Diffusion Flame Furnace#

Background#

In this tutorial, we will use the generalized eddy-dissipation model to analyze the methane-air combustion system. The combustion will be modeled using a global one-step reaction mechanism, assuming complete conversion of the fuel to \(CO_2\) and \(H_2O\). The reaction equation is

\[CH_4 + 2H_2O → CO_2 + 4H_2\]

This reaction will be defined in terms of stoichiometric coefficients, formation enthalpies, and parameters that control the reaction rate. The reaction rate will be determined assuming that turbulent mixing is the rate-limiting process, with the turbulence-chemistry interaction modeled using the eddy-dissipation model.

Setup and Solution#

Preparation#

Launch Fluent 2D in solution mode and print Fluent version.

import ansys.fluent.core as pyfluent

solver = pyfluent.launch_fluent(dimension=2)
print(solver.get_fluent_version())
Fluent version 2025 R1

Import some direct settings classes which will be used in the following sections. These classes allow straightforward access to various settings without the need to navigate through the settings hierarchy.

from pathlib import Path  # noqa: E402

from ansys.fluent.core import (  # noqa: E402
    Contour,
    Energy,
    Mesh,
    MixtureMaterial,
    PressureOutlet,
    Species,
    Vector,
    VelocityInlet,
    Viscous,
    WallBoundary,
)
from ansys.fluent.core.examples import download_file  # noqa: E402

Mesh#

Download the mesh file and read it into the Fluent session.

mesh_file = Path(download_file("gascomb.msh", "pyfluent/tutorials/species_transport"))
solver.settings.file.read_mesh(file_name=mesh_file)
Reading "gascomb.msh"...

Buffering for file scan...

    1705 nodes.
    1615 quadrilateral cells, zone  1.
    3141 2D interior faces, zone  4.
      58 2D symmetry faces, zone  5.
       9 2D wall faces, zone  2.
       5 2D velocity-inlet faces, zone  6.
      58 2D wall faces, zone  7.
      20 2D velocity-inlet faces, zone  8.
      28 2D pressure-outlet faces, zone  9.

Building...
     mesh
     materials,
     interface,
     domains,
     zones,
        pressure-outlet-9
        velocity-inlet-8
        wall-7
        velocity-inlet-6
        wall-2
        symmetry-5
        interior-4
        fluid-1
     parallel,
Done.

General Settings#

Check the mesh.

Fluent will perform various checks on the mesh and will report the progress in the console. Ensure that the reported minimum volume reported is a positive number.

solver.settings.mesh.check()
 Domain Extents:
   x-coordinate: min (m) = 0.000000e+00, max (m) = 1.800000e+03
   y-coordinate: min (m) = 0.000000e+00, max (m) = 2.250000e+02
 Volume statistics:
   minimum volume (m3): 3.333333e+00
   maximum volume (m3): 2.498387e+03
     total volume (m3): 4.049600e+05
 Face area statistics:
   minimum face area (m2): 1.000000e+00
   maximum face area (m2): 1.096768e+02
 Checking mesh............................
Done.

Scale the mesh and check it again.

Since this mesh was created in units of millimeters, we will need to scale the mesh into meters.

Note

We should check the mesh after we manipulate it (scale, convert to polyhedra, merge, separate, fuse, add zones, or smooth and swap). This will ensure that the quality of the mesh has not been compromised.

solver.settings.mesh.scale(x_scale=0.001, y_scale=0.001)
solver.settings.mesh.check()
 Domain Extents:
   x-coordinate: min (m) = 0.000000e+00, max (m) = 1.800000e+00
   y-coordinate: min (m) = 0.000000e+00, max (m) = 2.250000e-01
 Volume statistics:
   minimum volume (m3): 3.333333e-06
   maximum volume (m3): 2.498387e-03
     total volume (m3): 4.049600e-01
 Face area statistics:
   minimum face area (m2): 1.000000e-03
   maximum face area (m2): 1.096768e-01
 Checking mesh............................
Done.

Display the mesh in Fluent and save the image to a file to examine locally.

mesh = Mesh(solver, new_instance_name="mesh")
mesh.surfaces_list = mesh.surfaces_list.allowed_values()
mesh.display()
graphics = solver.settings.results.graphics
graphics.views.auto_scale()
if graphics.picture.use_window_resolution.is_active():
    graphics.picture.use_window_resolution = False
graphics.picture.x_resolution = 3840
graphics.picture.y_resolution = 2880
graphics.picture.save_picture(file_name="mesh.png")
../../_images/mesh.png

The Quadrilateral Mesh for the Combustor Model#

Inspect the available options for the two-dimensional space setting and set it to axisymmetric.

solver.settings.setup.general.solver.two_dim_space.allowed_values()
['swirl', 'axisymmetric', 'planar']
solver.settings.setup.general.solver.two_dim_space = "axisymmetric"

Models#

Enable heat transfer by enabling the energy model.

Energy(solver).enabled = True

Inspect the default settings for the k-ω SST viscous model.

Viscous(solver).print_state()
model : k-omega
k_omega_model : sst
k_omega_options :
  kw_low_re_correction : False
near_wall_treatment :
  wall_omega_treatment : correlation
transition_module : none
options :
  viscous_heating : False
  production_kato_launder_enabled : False
  production_limiter :
    enabled : True
    clip_factor : 10.0
turbulence_expert :
  turb_non_newtonian : False
  thermal_p_function : True
  restore_sst_v61 : False
user_defined :
  turb_visc_func : none
  energy_prandtl : none
  wall_prandtl : none

Inspect the available options for the species model and set it to species transport.

species = Species(solver)
species.model.option.allowed_values()
['off', 'species-transport', 'non-premixed-combustion', 'premixed-combustion', 'partially-premixed-combustion', 'pdf-transport']
species.model.option = "species-transport"
Adjusting the following setting:
Density explicit underrelaxation factor: from:     1   to:  0.25

Inspect the species model settings.

species.print_state()
model :
  option : species-transport
  material : mixture-template
  number_vol_spec : 3
options :
  inlet_diffusion : False
  thermal_diffusion : False
  diffusion_energy_source : True
  multi_component_diffusion : False
  save_gradients : False
  species_transport_expert : False
reactions :
  enable_volumetric_reactions : False
species_transport_expert_options :
  linearize_convection_source : False
  linearize_diffusion_source : False
  blending : False

Enable volumetric reactions.

species.reactions.enable_volumetric_reactions = True

Set the material to methane-air.

Note

The available material list contains the set of chemical mixtures that exist in the Ansys Fluent database. We can select one of the predefined mixtures to access a complete description of the reacting system. The chemical species in the system and their physical and thermodynamic properties are defined by our selection of the mixture material. We can alter the mixture material selection or modify the mixture material properties using the material settings (see Materials).

species.model.material = "methane-air"
There are 5 species in the selected mixture

Set the turbulence-chemistry interaction model to eddy-dissipation.

The eddy-dissipation model computes the rate of reaction under the assumption that chemical kinetics are fast compared to the rate at which reactants are mixed by turbulent fluctuations (eddies).

species.turb_chem_interaction_model = "eddy-dissipation"
Material methane-air:
  Changing method of "Reaction" to "eddy-dissipation".

Material mixture-template:
  Changing method of "Reaction" to "eddy-dissipation".

Inspect the species model settings after the changes.

species.print_state()
model :
  option : species-transport
  material : methane-air
  number_vol_spec : 5
options :
  inlet_diffusion : False
  thermal_diffusion : False
  diffusion_energy_source : True
  multi_component_diffusion : False
  save_gradients : False
  species_transport_expert : False
reactions :
  enable_volumetric_reactions : True
  enable_electrochemical_surface : False
turb_chem_interaction_model : eddy-dissipation
turb_chem_interaction_model_options :
species_transport_expert_options :
  linearize_convection_source : False
  linearize_diffusion_source : False
  blending : False
chemistry_solver : non-direct-source

Materials#

In this step, we will examine the default settings for the mixture material. This tutorial uses mixture properties copied from the Ansys Fluent database. In general, we can modify these or create our own mixture properties for our specific problem as necessary.

Print some specific properties of the mixture material (methane-air). We avoid printing the entire state of the mixture material to keep the output concise.

mixture_material = MixtureMaterial(solver, name="methane-air")
print(f"Species list: {mixture_material.species.volumetric_species.get_object_names()}")
print(f"Reactions option: {mixture_material.reactions.option()}")
print(f"Density option: {mixture_material.density.option()}")
print(f"Cp (specific heat) option: {mixture_material.specific_heat.option()}")
print(f"Thermal conductivity value: {mixture_material.thermal_conductivity.value()}")
print(f"Viscosity value: {mixture_material.viscosity.value()}")
print(f"Mass diffusivity value: {mixture_material.mass_diffusivity.value()}")
Species list: ['ch4', 'o2', 'co2', 'h2o', 'n2']
Reactions option: eddy-dissipation
Density option: incompressible-ideal-gas
Cp (specific heat) option: mixing-law
Thermal conductivity value: 0.0454
Viscosity value: 1.72e-05
Mass diffusivity value: 2.88e-05

Boundary Conditions#

Convert the symmetry zone to the axis type.

The symmetry zone must be converted to an axis to prevent numerical difficulties where the radius reduces to zero.

solver.settings.setup.boundary_conditions.set_zone_type(
    zone_list=["symmetry-5"], new_type="axis"
)

Set the boundary conditions for the air inlet (velocity-inlet-8).

Set the zone name to air-inlet.

This name is more descriptive for the zone than velocity-inlet-8.

solver.settings.setup.boundary_conditions.set_zone_name(
    zonename="velocity-inlet-8", newname="air-inlet"
)

Set the following boundary conditions for the air-inlet:

  • Velocity magnitude: 0.5 m/s

  • Turbulent intensity: 10%

  • Hydraulic diameter: 0.44 m

  • Temperature: 300 K

  • Species mass fraction for o2: 0.23

air_inlet = VelocityInlet(solver, name="air-inlet")
air_inlet.momentum.velocity_magnitude = 0.5
air_inlet.turbulence.turbulence_specification = "Intensity and Hydraulic Diameter"
air_inlet.turbulence.turbulent_intensity = 0.1
air_inlet.turbulence.hydraulic_diameter = 0.44
air_inlet.thermal.temperature = 300
air_inlet.species.species_mass_fraction["o2"] = 0.23

Verify the state of the air-inlet boundary condition after the changes.

air_inlet.print_state()
name : air-inlet
momentum :
  velocity_specification_method : Magnitude, Normal to Boundary
  reference_frame : Absolute
  velocity_magnitude :
    option : value
    value : 0.5
  initial_gauge_pressure :
    option : value
    value : 0
turbulence :
  turbulence_specification : Intensity and Hydraulic Diameter
  turbulent_intensity : 0.1
  hydraulic_diameter : 0.44
thermal :
  temperature :
    option : value
    value : 300
species :
  specify_species_in_mole_fractions : False
  species_mass_fraction :
    ch4 :
      option : value
      value : 0
    co2 :
      option : value
      value : 0
    h2o :
      option : value
      value : 0
    o2 :
      option : value
      value : 0.23

Set the boundary conditions for the fuel inlet (velocity-inlet-6).

Set the zone name to fuel-inlet.

This name is more descriptive for the zone than velocity-inlet-6.

solver.settings.setup.boundary_conditions.set_zone_name(
    zonename="velocity-inlet-6", newname="fuel-inlet"
)

Set the following boundary conditions for the fuel-inlet:

  • Velocity magnitude: 80 m/s

  • Turbulent intensity: 10%

  • Hydraulic diameter: 0.01 m

  • Temperature: 300 K

  • Species mass fraction for ch4: 1

fuel_inlet = VelocityInlet(solver, name="fuel-inlet")
fuel_inlet.momentum.velocity_magnitude = 80
fuel_inlet.turbulence.turbulence_specification = "Intensity and Hydraulic Diameter"
fuel_inlet.turbulence.turbulent_intensity = 0.1
fuel_inlet.turbulence.hydraulic_diameter = 0.01
fuel_inlet.thermal.temperature = 300
fuel_inlet.species.species_mass_fraction["ch4"] = 1

Verify the state of the fuel-inlet boundary condition after the changes.

fuel_inlet.print_state()
name : fuel-inlet
momentum :
  velocity_specification_method : Magnitude, Normal to Boundary
  reference_frame : Absolute
  velocity_magnitude :
    option : value
    value : 80
  initial_gauge_pressure :
    option : value
    value : 0
turbulence :
  turbulence_specification : Intensity and Hydraulic Diameter
  turbulent_intensity : 0.1
  hydraulic_diameter : 0.01
thermal :
  temperature :
    option : value
    value : 300
species :
  specify_species_in_mole_fractions : False
  species_mass_fraction :
    ch4 :
      option : value
      value : 1
    co2 :
      option : value
      value : 0
    h2o :
      option : value
      value : 0
    o2 :
      option : value
      value : 0

Set the following boundary conditions for the exit boundary (pressure-outlet-9):

  • Gauge pressure: 0 Pa

  • Backflow turbulence intensity: 10%

  • Backflow Hydraulic diameter: 0.45 m

  • Backflow total temperature: 300 K

  • Backflow species mass fraction for o2: 0.23

The Backflow values in the pressure outlet boundary condition are utilized only when backflow occurs at the pressure outlet. Always assign reasonable values because backflow may occur during intermediate iterations and could affect the solution stability.

pressure_outlet = PressureOutlet(solver, name="pressure-outlet-9")
pressure_outlet.momentum.gauge_pressure = 0
pressure_outlet.turbulence.turbulence_specification = "Intensity and Hydraulic Diameter"
pressure_outlet.turbulence.backflow_turbulent_intensity = 0.1
pressure_outlet.turbulence.backflow_hydraulic_diameter = 0.45
pressure_outlet.thermal.backflow_total_temperature = 300
pressure_outlet.species.backflow_species_mass_fraction["o2"] = 0.23

Verify the state of the pressure-outlet boundary condition after the changes.

pressure_outlet.print_state()
name : pressure-outlet-9
momentum :
  backflow_reference_frame : Absolute
  gauge_pressure :
    option : value
    value : 0
  pressure_profile_multiplier : 1.0
  backflow_dir_spec_method : Normal to Boundary
  backflow_pressure_spec : Total Pressure
  prevent_reverse_flow : False
  avg_pressure_spec : False
  target_mass_flow_rate : False
turbulence :
  turbulence_specification : Intensity and Hydraulic Diameter
  backflow_turbulent_intensity : 0.1
  backflow_hydraulic_diameter : 0.45
thermal :
  backflow_total_temperature :
    option : value
    value : 300
species :
  specify_species_in_mole_fractions : False
  backflow_species_mass_fraction :
    ch4 :
      option : value
      value : 0
    co2 :
      option : value
      value : 0
    h2o :
      option : value
      value : 0
    o2 :
      option : value
      value : 0.23

Set the boundary conditions for the outer wall (wall-7).

Set the zone name to outer-wall.

This name is more descriptive for the zone than wall-7.

solver.settings.setup.boundary_conditions.set_zone_name(
    zonename="wall-7", newname="outer-wall"
)

Set the following boundary conditions for the outer-wall:

  • Temperature: 300 K

outer_wall = WallBoundary(solver, name="outer-wall")
outer_wall.thermal.thermal_condition = "Temperature"
outer_wall.thermal.temperature = 300

Verify the state of thermal properties of the outer-wall boundary condition after the changes.

outer_wall.thermal.print_state()
thermal_condition : Temperature
material : aluminum
temperature :
  option : value
  value : 300
wall_thickness :
  option : value
  value : 0
heat_generation_rate :
  option : value
  value : 0
caf :
  option : value
  value : 1

Set the boundary conditions for the fuel inlet nozzle (wall-2).

Set the zone name to nozzle.

This name is more descriptive for the zone than wall-2.

solver.settings.setup.boundary_conditions.set_zone_name(
    zonename="wall-2", newname="nozzle"
)

Set the following boundary conditions for the nozzle for adiabatic wall conditions:

  • Heat flux: 0 \(W/m^2\)

nozzle = WallBoundary(solver, name="nozzle")
nozzle.thermal.thermal_condition = "Heat Flux"
nozzle.thermal.heat_flux = 0

Verify the state of thermal properties of the nozzle boundary condition after the changes.

nozzle.thermal.print_state()
thermal_condition : Heat Flux
material : aluminum
heat_flux :
  option : value
  value : 0
wall_thickness :
  option : value
  value : 0
heat_generation_rate :
  option : value
  value : 0
caf :
  option : value
  value : 1

Reaction Solution#

We will calculate a solution for the reacting flow.

Inspect the solution methods settings.

solver.settings.solution.methods.print_state()
p_v_coupling :
  flow_scheme : Coupled
flux_type :
  pbns_cases :
    flux_auto_select : True
    flux_type : Rhie-Chow: momentum based
spatial_discretization :
  gradient_scheme : least-square-cell-based
  discretization_scheme :
    k : second-order-upwind
    mom : second-order-upwind
    omega : second-order-upwind
    pressure : second-order
    species-0 : second-order-upwind
    species-1 : second-order-upwind
    species-2 : second-order-upwind
    species-3 : second-order-upwind
    temperature : second-order-upwind
pseudo_time_method :
  formulation :
    coupled_solver : global-time-step
expert :
  reactions : True
  reaction_source_term_relaxation_factor : 1.0
  numerics_pbns :
    implicit_bodyforce_treatment : False
    velocity_formulation : absolute
    physical_velocity_formulation : False
    disable_rhie_chow_flux : False
    presto_pressure_scheme : False
    first_to_second_order_blending : 1.0
high_order_term_relaxation :
  enable : False
warped_face_gradient_correction :
  enable : False
species_disc_together : False

Ensure that plot is enabled in residual monitor options.

solver.settings.solution.monitor.residual.options.plot()
True

Initialize the field variables.

solver.settings.solution.initialization.hybrid_initialize()
Initialize using the hybrid initialization method.

Checking case topology...
-This case has both inlets & outlets
-Pressure information is not available at the boundaries.
 Case will be initialized with constant pressure

        iter            scalar-0

        1               1.000000e+00
        2               3.835177e-06
        3               3.116578e-07
        4               2.563081e-08
        5               2.109805e-09
        6               1.736817e-10
        7               1.429777e-11
        8               1.171677e-12
        9               1.023421e-13
        10              1.000789e-14

Hybrid initialization is done.

Initializing mass fractions of
    ch4   o2   co2   h2o
to 0.01 for Eddy-Dissipation ignition.

Save the case file (gascomb1.cas.h5).

solver.settings.file.write_case(file_name="gascomb1.cas.h5")
Fast-loading "/ansys_inc/v251/fluent/fluent25.1.0/addons/afd/lib/hdfio.bin"
Done.

Writing to 30b945f663a6:"/mnt/pyfluent/gascomb1.cas.h5" in NODE0 mode and compression level 1 ...
Grouping cells for Laplace smoothing ...
        1615 cells,     1 zone  ...
        3319 faces,     7 zones ...
        1705 nodes,     1 zone  ...
  Done.
Done.

Run the calculation for 200 iterations.

solver.settings.solution.run_calculation.iterate(iter_count=200)
  iter  continuity  x-velocity  y-velocity      energy           k       omega         ch4          o2         co2         h2o     time/iter
 temperature limited to 5.000000e+03 in 36 cells on zone 1 in domain 1
      1  1.0000e+00  2.8826e-02  1.9174e-02  4.6440e-02  2.6366e-01  6.7015e-01  3.9592e-02  1.4869e-01  3.4007e-02  2.9870e-02  0:00:10  199
     2  1.0000e+00  3.5666e-02  2.1722e-02  7.1504e-03  4.9893e-02  1.2118e-01  6.2070e-02  4.5739e-02  5.5486e-03  5.5019e-03  0:00:12  198
     3  1.0000e+00  3.3955e-02  1.3257e-02  7.6401e-03  5.4174e-02  8.5282e-02  4.0745e-02  1.8683e-02  8.0401e-03  8.0555e-03  0:00:13  197
     4  1.0000e+00  4.4596e-02  1.0069e-02  7.8902e-03  7.5493e-02  7.2995e-02  1.8150e-02  1.4173e-02  9.0270e-03  9.1146e-03  0:00:13  196
     5  1.0000e+00  4.1067e-02  7.7328e-03  5.5725e-03  6.5997e-02  6.9267e-02  1.0832e-02  1.1928e-02  8.1723e-03  7.8901e-03  0:00:13  195
     6  1.0692e+00  3.4400e-02  5.6051e-03  4.6318e-03  4.3506e-02  5.3967e-02  7.1736e-03  1.0468e-02  6.7089e-03  6.5196e-03  0:00:13  194
     7  1.1962e+00  2.8974e-02  4.5099e-03  4.2423e-03  2.8360e-02  3.9524e-02  5.7701e-03  9.2417e-03  5.5549e-03  5.4469e-03  0:00:14  193
     8  1.3274e+00  2.5402e-02  3.5631e-03  4.0078e-03  2.0264e-02  2.9132e-02  4.8462e-03  8.3787e-03  4.9930e-03  4.9204e-03  0:00:14  192
     9  1.3793e+00  2.2675e-02  2.9011e-03  3.7286e-03  1.6773e-02  2.2117e-02  4.2519e-03  7.6729e-03  4.6888e-03  4.6607e-03  0:00:14  191
    10  1.3590e+00  2.0183e-02  2.4325e-03  3.4266e-03  1.3579e-02  1.6561e-02  3.6275e-03  6.7757e-03  4.4830e-03  4.4618e-03  0:00:14  190
    11  1.3243e+00  1.8005e-02  2.0881e-03  3.2174e-03  1.1109e-02  1.2503e-02  3.0570e-03  5.6272e-03  4.0900e-03  4.0646e-03  0:00:22  189

  iter  continuity  x-velocity  y-velocity      energy           k       omega         ch4          o2         co2         h2o     time/iter
    12  1.2981e+00  1.6015e-02  1.8316e-03  2.9872e-03  8.9633e-03  1.0166e-02  2.5681e-03  4.7761e-03  3.7870e-03  3.7814e-03  0:00:21  188
    13  1.2708e+00  1.4127e-02  1.6151e-03  2.7627e-03  7.2213e-03  8.0496e-03  2.2394e-03  3.9926e-03  3.2169e-03  3.2124e-03  0:00:19  187
    14  1.2320e+00  1.2421e-02  1.4198e-03  2.3752e-03  5.7441e-03  6.4755e-03  1.9033e-03  3.2345e-03  2.6924e-03  2.6901e-03  0:00:18  186
    15  1.1727e+00  1.0900e-02  1.2516e-03  1.9646e-03  4.8136e-03  5.4285e-03  1.5791e-03  2.6997e-03  2.2201e-03  2.2170e-03  0:00:18  185
    16  1.0887e+00  9.5701e-03  1.1065e-03  1.6440e-03  4.1961e-03  4.6501e-03  1.2966e-03  2.2128e-03  1.8121e-03  1.8123e-03  0:00:17  184
    17  9.8844e-01  8.3037e-03  9.7512e-04  1.3204e-03  3.6089e-03  4.0329e-03  1.0885e-03  1.8326e-03  1.4521e-03  1.4518e-03  0:00:16  183
    18  8.7814e-01  7.3899e-03  8.3648e-04  1.0900e-03  3.0962e-03  3.3631e-03  9.0410e-04  1.5487e-03  1.1798e-03  1.1801e-03  0:00:16  182
    19  7.7585e-01  6.4605e-03  7.2467e-04  9.2991e-04  2.7398e-03  2.9672e-03  7.5231e-04  1.3186e-03  9.5184e-04  9.5107e-04  0:00:15  181
    20  6.7820e-01  5.6455e-03  6.3492e-04  7.7791e-04  2.4474e-03  2.5511e-03  6.3057e-04  1.1063e-03  7.8948e-04  7.8898e-04  0:00:15  180
    21  5.8514e-01  4.9102e-03  5.6112e-04  6.5067e-04  2.2931e-03  2.2844e-03  5.1742e-04  9.7742e-04  7.0009e-04  6.9959e-04  0:00:15  179
    22  5.1597e-01  4.2773e-03  5.1700e-04  5.4157e-04  2.0893e-03  2.0184e-03  4.3349e-04  8.6540e-04  5.8095e-04  5.8049e-04  0:00:15  178

  iter  continuity  x-velocity  y-velocity      energy           k       omega         ch4          o2         co2         h2o     time/iter
    23  4.3739e-01  3.8274e-03  4.6114e-04  4.6371e-04  1.9375e-03  1.8473e-03  3.7154e-04  7.8419e-04  5.2614e-04  5.2581e-04  0:00:15  177
    24  3.7846e-01  3.4272e-03  4.1923e-04  4.1347e-04  1.8026e-03  1.6797e-03  3.2042e-04  7.3926e-04  4.7990e-04  4.7969e-04  0:00:14  176
    25  3.3461e-01  3.0316e-03  3.9318e-04  3.7164e-04  1.6594e-03  1.5339e-03  2.8099e-04  6.9245e-04  4.3380e-04  4.3376e-04  0:00:14  175
    26  2.9432e-01  2.7206e-03  3.6132e-04  3.3364e-04  1.5196e-03  1.4159e-03  2.5137e-04  6.4412e-04  3.9751e-04  3.9731e-04  0:00:14  174
    27  2.6659e-01  2.4575e-03  3.2995e-04  3.0740e-04  1.3848e-03  1.2880e-03  2.2506e-04  5.9354e-04  3.4979e-04  3.4955e-04  0:00:14  173
    28  2.4375e-01  2.2219e-03  3.0093e-04  2.8031e-04  1.2680e-03  1.1752e-03  1.9718e-04  5.4710e-04  3.0998e-04  3.0977e-04  0:00:14  172
    29  2.2321e-01  2.0166e-03  2.7590e-04  2.5177e-04  1.1671e-03  1.0690e-03  1.6966e-04  4.9919e-04  2.8066e-04  2.8043e-04  0:00:14  171
    30  2.0585e-01  1.8317e-03  2.5567e-04  2.2253e-04  1.0746e-03  9.7939e-04  1.4552e-04  4.4839e-04  2.4943e-04  2.4922e-04  0:00:14  170
    31  1.9161e-01  1.6690e-03  2.3487e-04  1.9304e-04  9.9016e-04  8.9977e-04  1.2177e-04  4.0343e-04  2.1764e-04  2.1798e-04  0:00:13  169
    32  1.7906e-01  1.5244e-03  2.1818e-04  1.6581e-04  9.1151e-04  8.2861e-04  1.0002e-04  3.5773e-04  1.8865e-04  1.8849e-04  0:00:13  168
    33  1.6774e-01  1.3970e-03  2.0101e-04  1.4223e-04  8.3596e-04  7.6454e-04  8.2743e-05  3.1144e-04  1.6237e-04  1.6230e-04  0:00:13  167

  iter  continuity  x-velocity  y-velocity      energy           k       omega         ch4          o2         co2         h2o     time/iter
    34  1.5696e-01  1.2827e-03  1.8649e-04  1.2108e-04  7.6381e-04  7.0321e-04  6.9354e-05  2.6707e-04  1.3894e-04  1.3891e-04  0:00:13  166
    35  1.4685e-01  1.1831e-03  1.7234e-04  1.0285e-04  6.8665e-04  6.4380e-04  5.8720e-05  2.3069e-04  1.2022e-04  1.2019e-04  0:00:13  165
    36  1.3481e-01  1.1053e-03  1.5621e-04  9.1006e-05  6.2932e-04  5.9405e-04  4.9125e-05  2.0291e-04  1.0577e-04  1.0574e-04  0:00:12  164
    37  1.2848e-01  1.0212e-03  1.4754e-04  7.6609e-05  5.6345e-04  5.4414e-04  4.2682e-05  1.7779e-04  8.9794e-05  8.9761e-05  0:00:12  163
    38  1.1801e-01  9.5762e-04  1.3535e-04  6.9377e-05  5.1517e-04  5.0438e-04  3.7616e-05  1.6185e-04  8.2473e-05  8.2447e-05  0:00:12  162
    39  1.1189e-01  8.9111e-04  1.2779e-04  5.9480e-05  4.6108e-04  4.6376e-04  3.3398e-05  1.5008e-04  7.4284e-05  7.4243e-05  0:00:12  161
    40  1.0253e-01  8.3804e-04  1.1812e-04  5.6994e-05  4.2107e-04  4.2955e-04  2.9508e-05  1.4180e-04  7.0888e-05  7.0857e-05  0:00:12  160
    41  9.7426e-02  7.8236e-04  1.1056e-04  5.1328e-05  3.7829e-04  3.9470e-04  2.6283e-05  1.3571e-04  6.6004e-05  6.5973e-05  0:00:12  159
    42  8.9433e-02  7.3868e-04  1.0341e-04  4.9780e-05  3.4256e-04  3.6341e-04  2.3534e-05  1.2766e-04  6.2693e-05  6.2663e-05  0:00:12  158
    43  8.4454e-02  6.9708e-04  9.6564e-05  4.7888e-05  3.1432e-04  3.3621e-04  2.1388e-05  1.2082e-04  6.0040e-05  6.0015e-05  0:00:12  157
    44  8.1112e-02  6.5333e-04  9.0611e-05  4.3112e-05  2.8558e-04  3.1075e-04  1.9854e-05  1.1758e-04  5.6158e-05  5.6127e-05  0:00:12  156

  iter  continuity  x-velocity  y-velocity      energy           k       omega         ch4          o2         co2         h2o     time/iter
    45  7.5241e-02  6.1671e-04  8.4945e-05  4.2296e-05  2.6121e-04  2.8969e-04  1.8218e-05  1.1142e-04  5.4231e-05  5.4212e-05  0:00:12  155
    46  7.1387e-02  5.8324e-04  7.9330e-05  3.9057e-05  2.3949e-04  2.7075e-04  1.6700e-05  1.0586e-04  5.2007e-05  5.1992e-05  0:00:12  154
    47  6.7955e-02  5.5112e-04  7.3988e-05  3.6401e-05  2.2042e-04  2.5412e-04  1.5422e-05  1.0083e-04  4.8040e-05  4.8014e-05  0:00:12  153
    48  6.4660e-02  5.2060e-04  6.9366e-05  3.4344e-05  2.0350e-04  2.3914e-04  1.4296e-05  9.5725e-05  4.6186e-05  4.6152e-05  0:00:11  152
    49  6.1716e-02  4.9168e-04  6.5292e-05  3.2262e-05  1.8837e-04  2.2570e-04  1.3283e-05  9.0859e-05  4.3880e-05  4.3851e-05  0:00:11  151
    50  5.8634e-02  4.6459e-04  6.1491e-05  3.0277e-05  1.7488e-04  2.1347e-04  1.2389e-05  8.6169e-05  4.1648e-05  4.1622e-05  0:00:12  150
    51  5.5787e-02  4.3916e-04  5.7824e-05  2.8217e-05  1.6264e-04  2.0251e-04  1.1546e-05  8.1563e-05  3.8070e-05  3.8045e-05  0:00:12  149
    52  5.3308e-02  4.1496e-04  5.4360e-05  2.6565e-05  1.5146e-04  1.9263e-04  1.0823e-05  7.7485e-05  3.6448e-05  3.6421e-05  0:00:11  148
    53  5.0855e-02  3.9229e-04  5.1090e-05  2.4733e-05  1.4121e-04  1.8350e-04  1.0064e-05  7.3572e-05  3.3658e-05  3.3633e-05  0:00:11  147
    54  4.8466e-02  3.7111e-04  4.8094e-05  2.3349e-05  1.3184e-04  1.7515e-04  9.4115e-06  6.9827e-05  3.2351e-05  3.2324e-05  0:00:11  146
    55  4.6268e-02  3.5145e-04  4.5166e-05  2.1844e-05  1.2319e-04  1.6740e-04  8.7746e-06  6.6321e-05  2.9971e-05  2.9949e-05  0:00:11  145

  iter  continuity  x-velocity  y-velocity      energy           k       omega         ch4          o2         co2         h2o     time/iter
    56  4.4294e-02  3.3299e-04  4.2264e-05  2.0589e-05  1.1520e-04  1.6034e-04  8.2535e-06  6.2972e-05  2.8229e-05  2.8210e-05  0:00:11  144
    57  4.2414e-02  3.1564e-04  3.9532e-05  1.9548e-05  1.0780e-04  1.5378e-04  7.8192e-06  5.9928e-05  2.6782e-05  2.6763e-05  0:00:11  143
    58  4.0635e-02  2.9932e-04  3.7148e-05  1.8612e-05  1.0088e-04  1.4767e-04  7.5744e-06  5.4996e-05  2.5448e-05  2.5430e-05  0:00:10  142
    59  3.8749e-02  2.8394e-04  3.4999e-05  1.7739e-05  9.4508e-05  1.4195e-04  7.1892e-06  5.1412e-05  2.4190e-05  2.4172e-05  0:00:10  141
    60  3.7243e-02  2.6946e-04  3.3135e-05  1.6929e-05  8.8618e-05  1.3652e-04  6.7893e-06  4.8515e-05  2.3052e-05  2.3040e-05  0:00:10  140
    61  3.5756e-02  2.5579e-04  3.1405e-05  1.6156e-05  8.3137e-05  1.3140e-04  6.4319e-06  4.6048e-05  2.1980e-05  2.1968e-05  0:00:10  139
    62  3.4323e-02  2.4294e-04  2.9727e-05  1.5412e-05  7.7998e-05  1.2656e-04  6.1118e-06  4.3819e-05  2.0969e-05  2.0956e-05  0:00:10  138
    63  3.2946e-02  2.3087e-04  2.8166e-05  1.4723e-05  7.3190e-05  1.2203e-04  5.8132e-06  4.1772e-05  2.0045e-05  2.0032e-05  0:00:10  137
    64  3.1627e-02  2.1948e-04  2.6727e-05  1.4090e-05  6.8718e-05  1.1771e-04  5.5377e-06  3.9924e-05  1.9174e-05  1.9163e-05  0:00:10  136
    65  3.0348e-02  2.0872e-04  2.5407e-05  1.3493e-05  6.4544e-05  1.1361e-04  5.2690e-06  3.8199e-05  1.8372e-05  1.8361e-05  0:00:10  135
    66  2.9134e-02  1.9855e-04  2.4126e-05  1.2939e-05  6.0673e-05  1.0967e-04  5.0201e-06  3.6583e-05  1.7515e-05  1.7505e-05  0:00:10  134

  iter  continuity  x-velocity  y-velocity      energy           k       omega         ch4          o2         co2         h2o     time/iter
    67  2.8014e-02  1.8897e-04  2.2985e-05  1.2370e-05  5.7080e-05  1.0586e-04  4.6967e-06  3.6143e-05  1.6945e-05  1.6935e-05  0:00:10  133
    68  2.6943e-02  1.8001e-04  2.1882e-05  1.1941e-05  5.3725e-05  1.0220e-04  4.6181e-06  3.4254e-05  1.6232e-05  1.6223e-05  0:00:10  132
    69  2.5993e-02  1.7151e-04  2.0848e-05  1.1425e-05  5.0595e-05  9.8642e-05  4.3559e-06  3.3679e-05  1.5701e-05  1.5693e-05  0:00:10  131
    70  2.5064e-02  1.6348e-04  1.9960e-05  1.1051e-05  4.7684e-05  9.5158e-05  4.2438e-06  3.1751e-05  1.5060e-05  1.5052e-05  0:00:10  130
    71  2.4170e-02  1.5588e-04  1.9139e-05  1.0585e-05  4.4971e-05  9.1793e-05  4.0001e-06  3.1202e-05  1.4493e-05  1.4486e-05  0:00:10  129
    72  2.3308e-02  1.4868e-04  1.8376e-05  1.0200e-05  4.2457e-05  8.8545e-05  3.8224e-06  3.0490e-05  1.3974e-05  1.3967e-05  0:00:10  128
    73  2.2514e-02  1.4186e-04  1.7650e-05  9.8330e-06  4.0150e-05  8.5443e-05  3.6664e-06  2.9621e-05  1.3476e-05  1.3470e-05  0:00:10  127
    74  2.1766e-02  1.3539e-04  1.6944e-05  9.4719e-06  3.7991e-05  8.2503e-05  3.5223e-06  2.8676e-05  1.3048e-05  1.3041e-05  0:00:10  126
    75  2.1066e-02  1.2938e-04  1.6239e-05  9.1722e-06  3.5934e-05  7.9689e-05  3.4357e-06  2.6570e-05  1.2509e-05  1.2503e-05  0:00:09  125
    76  2.0409e-02  1.2371e-04  1.5568e-05  8.8832e-06  3.4005e-05  7.6993e-05  3.2375e-06  2.6144e-05  1.2247e-05  1.2242e-05  0:00:09  124
    77  1.9743e-02  1.1833e-04  1.4966e-05  8.6415e-06  3.2184e-05  7.4404e-05  3.1473e-06  2.4718e-05  1.1785e-05  1.1779e-05  0:00:09  123

  iter  continuity  x-velocity  y-velocity      energy           k       omega         ch4          o2         co2         h2o     time/iter
    78  1.9127e-02  1.1321e-04  1.4459e-05  8.3960e-06  3.0440e-05  7.1893e-05  2.9754e-06  2.4585e-05  1.1548e-05  1.1543e-05  0:00:09  122
    79  1.8521e-02  1.0840e-04  1.3967e-05  8.1497e-06  2.8859e-05  6.9464e-05  2.8616e-06  2.4195e-05  1.1292e-05  1.1287e-05  0:00:09  121
    80  1.7957e-02  1.0372e-04  1.3495e-05  7.9559e-06  2.7417e-05  6.7095e-05  2.8000e-06  2.2834e-05  1.0892e-05  1.0888e-05  0:00:09  120
    81  1.7398e-02  9.9230e-05  1.3020e-05  7.6374e-06  2.6060e-05  6.4741e-05  2.6544e-06  2.2496e-05  1.0640e-05  1.0636e-05  0:00:21  119
    82  1.6856e-02  9.4956e-05  1.2565e-05  7.5445e-06  2.4766e-05  6.2393e-05  2.5282e-06  2.1360e-05  1.0255e-05  1.0251e-05  0:00:19  118
    83  1.6359e-02  9.0889e-05  1.2120e-05  7.2050e-06  2.3548e-05  6.0008e-05  2.4060e-06  2.1135e-05  1.0054e-05  1.0051e-05  0:00:17  117
    84  1.5913e-02  8.7028e-05  1.1687e-05  7.0878e-06  2.2418e-05  5.7612e-05  2.3175e-06  2.0096e-05  9.6488e-06  9.6452e-06  0:00:15  116
    85  1.5480e-02  8.3462e-05  1.1286e-05  6.7487e-06  2.1371e-05  5.5216e-05  2.2086e-06  1.9844e-05  9.4419e-06  9.4385e-06  0:00:14  115
    86  1.5022e-02  8.0066e-05  1.0924e-05  6.6343e-06  2.0401e-05  5.3119e-05  2.1452e-06  1.8842e-05  9.1088e-06  9.1053e-06  0:00:12  114
    87  1.4559e-02  7.6819e-05  1.0582e-05  6.3621e-06  1.9499e-05  5.1395e-05  2.0949e-06  1.8005e-05  8.8298e-06  8.8267e-06  0:00:12  113
    88  1.4097e-02  7.3696e-05  1.0222e-05  6.2676e-06  1.8669e-05  4.9734e-05  1.9927e-06  1.7553e-05  8.6541e-06  8.6512e-06  0:00:11  112

  iter  continuity  x-velocity  y-velocity      energy           k       omega         ch4          o2         co2         h2o     time/iter
    89  1.3657e-02  7.0742e-05  9.9061e-06  6.1148e-06  1.7896e-05  4.8112e-05  1.9064e-06  1.7160e-05  8.4810e-06  8.4785e-06  0:00:10  111
    90  1.3272e-02  6.7928e-05  9.6165e-06  5.9648e-06  1.7169e-05  4.6706e-05  1.8306e-06  1.6810e-05  8.3202e-06  8.3178e-06  0:00:10  110
    91  1.2905e-02  6.5235e-05  9.3382e-06  5.8493e-06  1.6484e-05  4.5335e-05  1.7626e-06  1.6510e-05  8.1767e-06  8.1742e-06  0:00:10  109
    92  1.2556e-02  6.2659e-05  9.0707e-06  5.7382e-06  1.5836e-05  4.4164e-05  1.7005e-06  1.6228e-05  8.0303e-06  8.0279e-06  0:00:10  108
    93  1.2245e-02  6.0198e-05  8.8095e-06  5.6355e-06  1.5225e-05  4.3355e-05  1.6429e-06  1.5958e-05  7.8448e-06  7.8423e-06  0:00:09  107
    94  1.1924e-02  5.7873e-05  8.5394e-06  5.4970e-06  1.4656e-05  4.2491e-05  1.5626e-06  1.6182e-05  7.7398e-06  7.7376e-06  0:00:09  106
    95  1.1591e-02  5.5669e-05  8.2713e-06  5.4138e-06  1.4118e-05  4.1578e-05  1.5133e-06  1.6332e-05  7.6708e-06  7.6687e-06  0:00:09  105
    96  1.1292e-02  5.3568e-05  8.0336e-06  5.3367e-06  1.3606e-05  4.0617e-05  1.4829e-06  1.6382e-05  7.6022e-06  7.5999e-06  0:00:08  104
    97  1.1019e-02  5.1562e-05  7.8210e-06  5.2787e-06  1.3104e-05  3.9643e-05  1.4376e-06  1.6297e-05  7.5364e-06  7.5340e-06  0:00:08  103
    98  1.0753e-02  4.9718e-05  7.6236e-06  5.2790e-06  1.2619e-05  3.8643e-05  1.3955e-06  1.6055e-05  7.4551e-06  7.4528e-06  0:00:08  102
    99  1.0548e-02  4.7976e-05  7.4451e-06  5.2328e-06  1.2172e-05  3.7636e-05  1.3550e-06  1.5833e-05  7.3827e-06  7.3807e-06  0:00:08  101

  iter  continuity  x-velocity  y-velocity      energy           k       omega         ch4          o2         co2         h2o     time/iter
   100  1.0303e-02  4.6318e-05  7.2496e-06  5.1768e-06  1.1756e-05  3.6628e-05  1.3243e-06  1.5636e-05  7.3152e-06  7.3133e-06  0:00:08  100
   101  1.0042e-02  4.4734e-05  7.0575e-06  5.1297e-06  1.1368e-05  3.5618e-05  1.3011e-06  1.5488e-05  7.2509e-06  7.2489e-06  0:00:08   99
   102  9.8180e-03  4.3213e-05  6.8667e-06  5.0908e-06  1.1001e-05  3.4630e-05  1.2810e-06  1.5348e-05  7.1837e-06  7.1820e-06  0:00:08   98
   103  9.6107e-03  4.1766e-05  6.6786e-06  5.0494e-06  1.0644e-05  3.3660e-05  1.2615e-06  1.5196e-05  7.1114e-06  7.1097e-06  0:00:07   97
   104  9.3982e-03  4.0419e-05  6.4997e-06  5.0012e-06  1.0294e-05  3.2715e-05  1.2423e-06  1.5024e-05  7.0311e-06  7.0290e-06  0:00:07   96
   105  9.1985e-03  3.9144e-05  6.3237e-06  4.9468e-06  9.9540e-06  3.1781e-05  1.2229e-06  1.4846e-05  6.9457e-06  6.9436e-06  0:00:07   95
   106  9.0254e-03  3.7949e-05  6.1599e-06  4.8860e-06  9.6265e-06  3.0860e-05  1.2022e-06  1.4665e-05  6.8588e-06  6.8566e-06  0:00:07   94
   107  8.8429e-03  3.6808e-05  6.0141e-06  4.8187e-06  9.3107e-06  2.9948e-05  1.1805e-06  1.4462e-05  6.7584e-06  6.7561e-06  0:00:07   93
   108  8.6411e-03  3.5722e-05  5.8510e-06  4.7414e-06  9.0050e-06  2.9045e-05  1.1530e-06  1.4296e-05  6.6595e-06  6.6555e-06  0:00:07   92
   109  8.4519e-03  3.4693e-05  5.7074e-06  4.6698e-06  8.7085e-06  2.8146e-05  1.1303e-06  1.4033e-05  6.5976e-06  6.5958e-06  0:00:07   91
   110  8.2756e-03  3.3699e-05  5.5682e-06  4.5943e-06  8.4199e-06  2.7252e-05  1.1085e-06  1.3791e-05  6.5288e-06  6.5267e-06  0:00:07   90

  iter  continuity  x-velocity  y-velocity      energy           k       omega         ch4          o2         co2         h2o     time/iter
   111  8.1082e-03  3.2737e-05  5.4286e-06  4.5109e-06  8.1398e-06  2.6369e-05  1.0745e-06  1.3561e-05  6.4650e-06  6.4629e-06  0:00:07   89
   112  7.9827e-03  3.1824e-05  5.2911e-06  4.4239e-06  7.8760e-06  2.5496e-05  1.0517e-06  1.3305e-05  6.3538e-06  6.3519e-06  0:00:07   88
   113  7.8425e-03  3.0977e-05  5.1661e-06  4.3336e-06  7.6227e-06  2.4631e-05  1.0300e-06  1.3036e-05  6.2105e-06  6.2082e-06  0:00:07   87
   114  7.7056e-03  3.0159e-05  5.0425e-06  4.2436e-06  7.3775e-06  2.3784e-05  1.0073e-06  1.2753e-05  6.0718e-06  6.0694e-06  0:00:07   86
   115  7.5657e-03  2.9363e-05  4.9139e-06  4.1662e-06  7.1352e-06  2.2963e-05  9.8899e-07  1.2462e-05  5.9273e-06  5.9250e-06  0:00:07   85
   116  7.4152e-03  2.8594e-05  4.7867e-06  4.0795e-06  6.8976e-06  2.2120e-05  9.6506e-07  1.2177e-05  5.7883e-06  5.7863e-06  0:00:06   84
   117  7.2541e-03  2.7840e-05  4.6728e-06  3.9895e-06  6.6617e-06  2.1528e-05  9.4014e-07  1.1872e-05  5.6378e-06  5.6357e-06  0:00:06   83
   118  7.1010e-03  2.7103e-05  4.5741e-06  3.8940e-06  6.4441e-06  2.1181e-05  9.1354e-07  1.1562e-05  5.4859e-06  5.4839e-06  0:00:06   82
   119  6.9391e-03  2.6385e-05  4.4821e-06  3.8173e-06  6.2472e-06  2.0818e-05  8.8687e-07  1.1280e-05  5.3530e-06  5.3511e-06  0:00:06   81
   120  6.7685e-03  2.5687e-05  4.3956e-06  3.7568e-06  6.0809e-06  2.0453e-05  8.6111e-07  1.1066e-05  5.2507e-06  5.2488e-06  0:00:06   80
   121  6.5967e-03  2.5008e-05  4.3140e-06  3.6937e-06  5.9296e-06  2.0087e-05  8.3944e-07  1.0815e-05  5.1272e-06  5.1254e-06  0:00:06   79

  iter  continuity  x-velocity  y-velocity      energy           k       omega         ch4          o2         co2         h2o     time/iter
   122  6.4224e-03  2.4355e-05  4.2381e-06  3.6110e-06  5.7846e-06  1.9746e-05  8.3949e-07  1.0683e-05  5.0761e-06  5.0743e-06  0:00:06   78
   123  6.2457e-03  2.3721e-05  4.1805e-06  3.6092e-06  5.6490e-06  1.9409e-05  8.0496e-07  1.0501e-05  4.9952e-06  4.9933e-06  0:00:06   77
   124  6.0855e-03  2.3128e-05  4.1220e-06  3.5407e-06  5.5215e-06  1.9039e-05  7.9982e-07  1.0358e-05  4.9307e-06  4.9292e-06  0:00:09   76
   125  5.9503e-03  2.2553e-05  4.0272e-06  3.4976e-06  5.3973e-06  1.8631e-05  7.8606e-07  1.0215e-05  4.8663e-06  4.8649e-06  0:00:08   75
   126  5.8422e-03  2.1986e-05  3.9374e-06  3.4550e-06  5.2750e-06  1.8190e-05  7.6658e-07  1.0065e-05  4.7970e-06  4.7957e-06  0:00:08   74
   127  5.7252e-03  2.1428e-05  3.8477e-06  3.4063e-06  5.1547e-06  1.7770e-05  7.4456e-07  9.9042e-06  4.7210e-06  4.7197e-06  0:00:07   73
   128  5.6035e-03  2.0908e-05  3.7608e-06  3.3515e-06  5.0386e-06  1.7324e-05  7.2166e-07  9.7289e-06  4.6376e-06  4.6364e-06  0:00:07   72
   129  5.4814e-03  2.0411e-05  3.6843e-06  3.2910e-06  4.9248e-06  1.6855e-05  6.9991e-07  9.5454e-06  4.5487e-06  4.5476e-06  0:00:06   71
   130  5.3586e-03  1.9923e-05  3.6087e-06  3.2256e-06  4.8101e-06  1.6380e-05  6.7951e-07  9.3532e-06  4.4548e-06  4.4539e-06  0:00:06   70
   131  5.2363e-03  1.9444e-05  3.5382e-06  3.1562e-06  4.6951e-06  1.5898e-05  6.5961e-07  9.1513e-06  4.3583e-06  4.3573e-06  0:00:06   69
   132  5.1124e-03  1.8969e-05  3.4662e-06  3.0834e-06  4.5787e-06  1.5416e-05  6.3987e-07  8.9409e-06  4.2497e-06  4.2487e-06  0:00:06   68

  iter  continuity  x-velocity  y-velocity      energy           k       omega         ch4          o2         co2         h2o     time/iter
   133  4.9877e-03  1.8501e-05  3.3936e-06  3.0106e-06  4.4616e-06  1.4938e-05  6.2047e-07  8.7265e-06  4.1450e-06  4.1440e-06  0:00:06   67
   134  4.8643e-03  1.8047e-05  3.3241e-06  2.9366e-06  4.3436e-06  1.4466e-05  6.0134e-07  8.5094e-06  4.0414e-06  4.0404e-06  0:00:05   66
   135  4.7427e-03  1.7614e-05  3.2543e-06  2.8614e-06  4.2248e-06  1.4003e-05  5.8247e-07  8.2881e-06  3.9363e-06  3.9354e-06  0:00:05   65
   136  4.6237e-03  1.7184e-05  3.1828e-06  2.7854e-06  4.1061e-06  1.3548e-05  5.6387e-07  8.0634e-06  3.8293e-06  3.8284e-06  0:00:05   64
   137  4.5112e-03  1.6758e-05  3.1130e-06  2.7087e-06  3.9886e-06  1.3104e-05  5.4530e-07  7.8360e-06  3.7208e-06  3.7199e-06  0:00:05   63
   138  4.4031e-03  1.6336e-05  3.0433e-06  2.6313e-06  3.8718e-06  1.2670e-05  5.2736e-07  7.6071e-06  3.6119e-06  3.6110e-06  0:00:05   62
   139  4.2897e-03  1.5921e-05  2.9750e-06  2.5541e-06  3.7560e-06  1.2244e-05  5.0996e-07  7.3799e-06  3.5033e-06  3.5025e-06  0:00:05   61
   140  4.1700e-03  1.5515e-05  2.9059e-06  2.4862e-06  3.6441e-06  1.1831e-05  4.9424e-07  7.1585e-06  3.3971e-06  3.3963e-06  0:00:05   60
   141  4.0523e-03  1.5116e-05  2.8402e-06  2.4154e-06  3.5325e-06  1.1425e-05  4.7834e-07  6.9404e-06  3.2928e-06  3.2920e-06  0:00:05   59
   142  3.9366e-03  1.4721e-05  2.7774e-06  2.3431e-06  3.4205e-06  1.1029e-05  4.6168e-07  6.7243e-06  3.1890e-06  3.1882e-06  0:00:05   58
   143  3.8238e-03  1.4332e-05  2.7205e-06  2.2709e-06  3.3097e-06  1.0645e-05  4.4469e-07  6.5086e-06  3.0855e-06  3.0848e-06  0:00:05   57

  iter  continuity  x-velocity  y-velocity      energy           k       omega         ch4          o2         co2         h2o     time/iter
   144  3.7141e-03  1.3947e-05  2.6692e-06  2.1997e-06  3.2007e-06  1.0273e-05  4.2708e-07  6.2928e-06  2.9823e-06  2.9817e-06  0:00:04   56
   145  3.6014e-03  1.3568e-05  2.6170e-06  2.1283e-06  3.0939e-06  9.9152e-06  4.0904e-07  6.0789e-06  2.8808e-06  2.8803e-06  0:00:04   55
   146  3.4903e-03  1.3225e-05  2.5635e-06  2.0571e-06  2.9898e-06  9.5627e-06  3.9089e-07  5.8676e-06  2.7810e-06  2.7806e-06  0:00:04   54
   147  3.3862e-03  1.2889e-05  2.5089e-06  1.9869e-06  2.8904e-06  9.2201e-06  3.7307e-07  5.6596e-06  2.6829e-06  2.6826e-06  0:00:04   53
   148  3.2924e-03  1.2557e-05  2.4546e-06  1.9178e-06  2.7947e-06  8.8876e-06  3.5602e-07  5.4555e-06  2.5872e-06  2.5869e-06  0:00:04   52
   149  3.1977e-03  1.2227e-05  2.3996e-06  1.8499e-06  2.7029e-06  8.5626e-06  3.3944e-07  5.2563e-06  2.4939e-06  2.4937e-06  0:00:04   51
   150  3.0998e-03  1.1900e-05  2.3436e-06  1.7837e-06  2.6158e-06  8.2465e-06  3.2353e-07  5.0638e-06  2.4032e-06  2.4030e-06  0:00:04   50
   151  2.9963e-03  1.1578e-05  2.2891e-06  1.7188e-06  2.5319e-06  7.9377e-06  3.0813e-07  4.8774e-06  2.3154e-06  2.3152e-06  0:00:04   49
   152  2.8940e-03  1.1259e-05  2.2364e-06  1.6559e-06  2.4516e-06  7.6355e-06  2.9325e-07  4.6958e-06  2.2299e-06  2.2297e-06  0:00:04   48
   153  2.7945e-03  1.0944e-05  2.1828e-06  1.5948e-06  2.3744e-06  7.3401e-06  2.7891e-07  4.5194e-06  2.1468e-06  2.1466e-06  0:00:04   47
   154  2.6964e-03  1.0634e-05  2.1362e-06  1.5353e-06  2.3001e-06  7.0519e-06  2.6505e-07  4.3486e-06  2.0663e-06  2.0662e-06  0:00:04   46

  iter  continuity  x-velocity  y-velocity      energy           k       omega         ch4          o2         co2         h2o     time/iter
   155  2.5969e-03  1.0327e-05  2.0906e-06  1.4779e-06  2.2285e-06  6.7728e-06  2.5200e-07  4.1832e-06  1.9881e-06  1.9880e-06  0:00:03   45
   156  2.4993e-03  1.0023e-05  2.0440e-06  1.4218e-06  2.1610e-06  6.5034e-06  2.3998e-07  4.0236e-06  1.9124e-06  1.9122e-06  0:00:03   44
   157  2.4041e-03  9.7244e-06  1.9968e-06  1.3676e-06  2.0951e-06  6.2483e-06  2.2826e-07  3.8691e-06  1.8390e-06  1.8388e-06  0:00:03   43
   158  2.3196e-03  9.4314e-06  1.9532e-06  1.3141e-06  2.0294e-06  6.0061e-06  2.1697e-07  3.7166e-06  1.7666e-06  1.7665e-06  0:00:03   42
   159  2.2350e-03  9.1409e-06  1.9094e-06  1.2591e-06  1.9679e-06  5.7602e-06  2.0598e-07  3.5574e-06  1.6911e-06  1.6910e-06  0:00:03   41
   160  2.1530e-03  8.8706e-06  1.8642e-06  1.2054e-06  1.9086e-06  5.5167e-06  1.9519e-07  3.4005e-06  1.6169e-06  1.6169e-06  0:00:03   40
   161  2.0729e-03  8.6113e-06  1.8181e-06  1.1545e-06  1.8502e-06  5.2798e-06  1.8467e-07  3.2488e-06  1.5452e-06  1.5452e-06  0:00:03   39
   162  1.9951e-03  8.3540e-06  1.7719e-06  1.1065e-06  1.7926e-06  5.0530e-06  1.7452e-07  3.1090e-06  1.4785e-06  1.4785e-06  0:00:03   38
   163  1.9184e-03  8.0999e-06  1.7260e-06  1.0607e-06  1.7362e-06  4.8353e-06  1.6491e-07  2.9756e-06  1.4154e-06  1.4154e-06  0:00:03   37
   164  1.8400e-03  7.8499e-06  1.6800e-06  1.0165e-06  1.6809e-06  4.6268e-06  1.5633e-07  2.8474e-06  1.3547e-06  1.3547e-06  0:00:03   36
   165  1.7645e-03  7.6026e-06  1.6341e-06  9.7433e-07  1.6264e-06  4.4242e-06  1.4812e-07  2.7245e-06  1.2963e-06  1.2964e-06  0:00:03   35

  iter  continuity  x-velocity  y-velocity      energy           k       omega         ch4          o2         co2         h2o     time/iter
   166  1.6913e-03  7.3596e-06  1.5885e-06  9.3390e-07  1.5729e-06  4.2295e-06  1.4029e-07  2.6061e-06  1.2403e-06  1.2403e-06  0:00:03   34
   167  1.6225e-03  7.1206e-06  1.5454e-06  8.9451e-07  1.5207e-06  4.0427e-06  1.3275e-07  2.4921e-06  1.1868e-06  1.1868e-06  0:00:03   33
   168  1.5571e-03  6.8864e-06  1.5078e-06  8.5647e-07  1.4697e-06  3.8634e-06  1.2552e-07  2.3827e-06  1.1353e-06  1.1354e-06  0:00:02   32
   169  1.4934e-03  6.6562e-06  1.4716e-06  8.1987e-07  1.4200e-06  3.6899e-06  1.1851e-07  2.2784e-06  1.0853e-06  1.0855e-06  0:00:02   31
   170  1.4322e-03  6.4365e-06  1.4350e-06  7.8430e-07  1.3718e-06  3.5211e-06  1.1176e-07  2.1775e-06  1.0378e-06  1.0380e-06  0:00:02   30
   171  1.3752e-03  6.2205e-06  1.3986e-06  7.4989e-07  1.3250e-06  3.3548e-06  1.0528e-07  2.0800e-06  9.9202e-07  9.9220e-07  0:00:02   29
   172  1.3177e-03  6.0074e-06  1.3620e-06  7.1640e-07  1.2801e-06  3.1946e-06  9.9040e-08  1.9848e-06  9.4721e-07  9.4738e-07  0:00:02   28
   173  1.2619e-03  5.7989e-06  1.3252e-06  6.8425e-07  1.2366e-06  3.0405e-06  9.3117e-08  1.8929e-06  9.0388e-07  9.0407e-07  0:00:05   27
   174  1.2088e-03  5.5965e-06  1.2885e-06  6.5329e-07  1.1944e-06  2.8924e-06  8.7649e-08  1.8059e-06  8.6286e-07  8.6305e-07  0:00:04   26
   175  1.1654e-03  5.3981e-06  1.2537e-06  6.3672e-07  1.1587e-06  2.7537e-06  8.3151e-08  1.7260e-06  8.3162e-07  8.3188e-07  0:00:04   25
   176  1.1405e-03  5.2066e-06  1.2223e-06  5.8504e-07  1.1172e-06  2.6222e-06  7.4876e-08  1.6691e-06  7.9396e-07  7.9393e-07  0:00:03   24

  iter  continuity  x-velocity  y-velocity      energy           k       omega         ch4          o2         co2         h2o     time/iter
   177  1.0854e-03  5.0131e-06  1.1938e-06  5.8210e-07  1.0822e-06  2.4963e-06  7.1968e-08  1.5798e-06  7.5219e-07  7.5245e-07  0:00:03   23
   178  1.0516e-03  4.8209e-06  1.1607e-06  5.3863e-07  1.0445e-06  2.3787e-06  7.0200e-08  1.5022e-06  7.2523e-07  7.2545e-07  0:00:02   22
   179  1.0201e-03  4.6342e-06  1.1302e-06  5.1573e-07  1.0068e-06  2.2649e-06  6.6730e-08  1.4322e-06  6.9447e-07  6.9468e-07  0:00:02   21
   180  9.8731e-04  4.4539e-06  1.1000e-06  4.9370e-07  9.7065e-07  2.1552e-06  6.2681e-08  1.3680e-06  6.6391e-07  6.6411e-07  0:00:02   20
!  180 solution is converged

Set time scale factor to 5.

The Time Scale Factor allows us to further manipulate the computed time step size calculated by Fluent. Larger time steps can lead to faster convergence. However, if the time step is too large it can lead to solution instability.

solver.settings.solution.run_calculation.pseudo_time_settings.time_step_method.time_step_size_scale_factor = (
    5
)

Run the calculation for 200 iterations.

solver.settings.solution.run_calculation.iterate(iter_count=200)
  iter  continuity  x-velocity  y-velocity      energy           k       omega         ch4          o2         co2         h2o     time/iter
   180  9.8731e-04  4.4539e-06  1.1000e-06  4.9370e-07  9.7065e-07  2.1552e-06  6.2681e-08  1.3680e-06  6.6391e-07  6.6411e-07  0:00:20  200
!  180 solution is converged
   181  2.4223e-03  4.5361e-06  1.1305e-06  9.6245e-07  1.4112e-06  2.7110e-06  1.2524e-07  2.7120e-06  1.3544e-06  1.3546e-06  0:00:18  199
   182  1.9375e-03  4.0183e-06  1.0338e-06  1.2183e-06  1.2315e-06  2.6664e-06  1.5388e-07  3.4098e-06  1.6380e-06  1.6381e-06  0:00:17  198
   183  1.7417e-03  3.5345e-06  9.3314e-07  1.1938e-06  1.0766e-06  2.4145e-06  1.5569e-07  3.2712e-06  1.5644e-06  1.5646e-06  0:00:17  197
   184  1.6240e-03  3.0544e-06  8.2972e-07  1.1005e-06  9.2646e-07  2.0884e-06  1.4862e-07  2.9967e-06  1.4167e-06  1.4171e-06  0:00:17  196
   185  1.5351e-03  2.6011e-06  7.2541e-07  9.6647e-07  7.7628e-07  1.7522e-06  1.3129e-07  2.5867e-06  1.2302e-06  1.2306e-06  0:00:17  195
   186  1.4126e-03  2.1942e-06  6.3148e-07  8.2632e-07  6.4811e-07  1.4628e-06  1.1152e-07  2.1964e-06  1.0501e-06  1.0504e-06  0:00:16  194
   187  1.3244e-03  1.8488e-06  5.5063e-07  6.9906e-07  5.4825e-07  1.2277e-06  9.4161e-08  1.8297e-06  8.8227e-07  8.8252e-07  0:00:16  193
   188  1.2604e-03  1.5605e-06  4.7758e-07  5.7674e-07  4.6165e-07  1.0204e-06  8.3312e-08  1.5060e-06  7.2567e-07  7.2585e-07  0:00:16  192
   189  1.1873e-03  1.3348e-06  4.1791e-07  4.8801e-07  3.9820e-07  8.4752e-07  7.2026e-08  1.2107e-06  5.9737e-07  5.9766e-07  0:00:16  191
   190  1.1166e-03  1.1344e-06  3.6601e-07  4.0447e-07  3.4083e-07  7.1274e-07  6.1061e-08  9.9514e-07  4.9642e-07  4.9663e-07  0:00:15  190

  iter  continuity  x-velocity  y-velocity      energy           k       omega         ch4          o2         co2         h2o     time/iter
   191  1.0304e-03  9.7570e-07  3.2135e-07  3.3209e-07  2.9517e-07  5.9745e-07  5.3908e-08  8.2685e-07  4.0947e-07  4.0963e-07  0:00:15  189
   192  9.3448e-04  8.4421e-07  2.8513e-07  2.7217e-07  2.5466e-07  5.0003e-07  4.8290e-08  6.8293e-07  3.3575e-07  3.3588e-07  0:00:15  188
!  192 solution is converged

Save the case and data files (gascomb1.cas.h5 and gascomb1.dat.h5).

solver.settings.file.write_case_data(file_name="gascomb1.cas.h5")
Writing to 30b945f663a6:"/mnt/pyfluent/gascomb1.cas.h5" in NODE0 mode and compression level 1 ...
Grouping cells for Laplace smoothing ...
        1615 cells,     1 zone  ...
        3319 faces,     7 zones ...
        1705 nodes,     1 zone  ...
  Done.
Done.

Writing to 30b945f663a6:"/mnt/pyfluent/gascomb1.dat.h5" in NODE0 mode and compression level 1 ...
  Writing results.
Done.

Postprocessing#

Review the solution by examining graphical displays of the results and performing surface integrations at the combustor exit.

Report the total sensible heat flux. We shall use wildcards to specify all zones.

solver.settings.results.report.fluxes.get_heat_transfer_sensible(zones="*")
{'Net': -0.5353470930422191, 'air-inlet': 173.7936396580586, 'fuel-inlet': 16.64962057794938, 'nozzle': -0.0, 'outer-wall': -12842.71004368723, 'pressure-outlet-9': -191740.9839789067}

Display filled contours of temperature and save the image to a file.

contour1 = Contour(solver, new_instance_name="contour-temp")
contour1.field = "temperature"
contour1.surfaces_list = contour1.surfaces_list.allowed_values()
contour1.coloring.option = "banded"
contour1.display()
graphics.views.auto_scale()
# graphics.picture.save_picture(file_name="contour-temp.png")
../../_images/contour-temp.png

Contours of Temperature#

The peak temperature is approximately 2300 K.

Display velocity vectors and save the image to a file.

vector1 = Vector(solver, new_instance_name="vector-vel")
vector1.surfaces_list = ["interior-4"]
vector1.scale.scale_f = 0.01
vector1.vector_opt.fixed_length = True

The fixed length option is useful when the vector magnitude varies dramatically. With fixed length vectors, the velocity magnitude is described only by color instead of by both vector length and color.

vector1.vector_opt.scale_head = 0.1
vector1.display()
graphics.views.auto_scale()
graphics.picture.save_picture(file_name="vector-vel.png")
../../_images/vector-vel.png

Velocity Vectors#

The entrainment of air into the high-velocity methane jet is clearly visible.

Display filled contours of mass fraction of \(CH_4\) and save the image to a file.

contour2 = Contour(solver, new_instance_name="contour-ch4-mass-fraction")
contour2.field = "ch4"
contour2.surfaces_list = contour2.surfaces_list.allowed_values()
contour2.display()
graphics.views.auto_scale()
graphics.picture.save_picture(file_name="contour-ch4-mass-fraction.png")
../../_images/contour-ch4-mass-fraction.png

Contours of \(CH_4\) Mass Fraction#

Display filled contours of mass fraction of \(O_2\) and save the image to a file.

contour3 = Contour(solver, new_instance_name="contour-o2-mass-fraction")
contour3.field = "o2"
contour3.surfaces_list = contour3.surfaces_list.allowed_values()
contour3.display()
graphics.views.auto_scale()
graphics.picture.save_picture(file_name="contour-o2-mass-fraction.png")
../../_images/contour-o2-mass-fraction.png

Contours of \(O_2\) Mass Fraction#

Display filled contours of mass fraction of \(CO_2\) and save the image to a file.

contour4 = Contour(solver, new_instance_name="contour-co2-mass-fraction")
contour4.field = "co2"
contour4.surfaces_list = contour4.surfaces_list.allowed_values()
contour4.display()
graphics.views.auto_scale()
graphics.picture.save_picture(file_name="contour-co2-mass-fraction.png")
../../_images/contour-co2-mass-fraction.png

Contours of \(CO_2\) Mass Fraction#

Display filled contours of mass fraction of \(H_2O\) and save the image to a file.

contour5 = Contour(solver, new_instance_name="contour-h2o-mass-fraction")
contour5.field = "h2o"
contour5.surfaces_list = contour5.surfaces_list.allowed_values()
contour5.display()
graphics.views.auto_scale()
graphics.picture.save_picture(file_name="contour-h2o-mass-fraction.png")
../../_images/contour-h2o-mass-fraction.png

Contours of \(H_2O\) Mass Fraction#

Determine the average exit temperature.

The mass-averaged temperature will be computed as:

\[\bar{T}=\frac{\int T \rho \vec{v} \cdot d \vec{A}}{\int \rho \vec{v} \cdot d \vec{A}}\]

The mass-averaged temperature at the exit is approximately 1840 K.

solver.settings.results.report.surface_integrals.get_mass_weighted_avg(
    report_of="temperature", surface_names=["pressure-outlet-9"]
)
{'pressure-outlet-9': 1840.02573809136}

Determine the average exit velocity.

The mass-averaged velocity will be computed as:

\[v=\frac{1}{A} \int v d A\]

The Area-Weighted Average field will show that the exit velocity is approximately 3.37 m/s.

solver.settings.results.report.surface_integrals.get_area_weighted_avg(
    report_of="velocity-magnitude", surface_names=["pressure-outlet-9"]
)
{'pressure-outlet-9': 3.305919548597063}

Save the case file (gascomb1.cas.h5).

solver.settings.file.write_case(file_name="gascomb1.cas.h5")
Writing to 30b945f663a6:"/mnt/pyfluent/gascomb1.cas.h5" in NODE0 mode and compression level 1 ...
Grouping cells for Laplace smoothing ...
        1615 cells,     1 zone  ...
        3319 faces,     7 zones ...
        1705 nodes,     1 zone  ...
  Done.
Done.

Close Fluent#

solver.exit()

Summary#

In this tutorial we used PyFluent to model the transport, mixing, and reaction of chemical species. The reaction system was defined by using a mixture-material entry in the Ansys Fluent database. The procedures used here for simulation of hydrocarbon combustion can be applied to other reacting flow systems.

Total running time of the script: (2 minutes 8.811 seconds)

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