[Lizz4rd]

Good Day,
i tried simulating the Sandia Flame F.
According to this Paper: https://tcg.mae.cornell.edu/pubs/Xu_P_CF_00.pdf (Page 288/289)

for this case, all the fractions stay the same. Only the velocity in the Main Inlet changes to 99.2, in the Pilot Jet to 22.8 and the Temperature in the Pilot jet changes to 1860K. The rest is copied from the tutorial.



When simulating this case, there is no ignition (as can be seen in the Picture - at 5500s)


Does somebody know what i need to change to get this simulation running.

Thank you very much

[godfatherBond]

Originally Posted by Lizz4rd

Good Day,
i tried simulating the Sandia Flame F.
According to this Paper: https://tcg.mae.cornell.edu/pubs/Xu_P_CF_00.pdf (Page 288/289)

for this case, all the fractions stay the same. Only the velocity in the Main Inlet changes to 99.2, in the Pilot Jet to 22.8 and the Temperature in the Pilot jet changes to 1860K. The rest is copied from the tutorial.



When simulating this case, there is no ignition (as can be seen in the Picture - at 5500s)


Does somebody know what i need to change to get this simulation running.

Thank you very much

Hello,
1. May I know what combustion model are you using? Were you able to run Flame D successfully? Not sure if the combustion model is active from the plots shown above. I see not jet or its almost broken up only a few mm from the exit plane.
2. Flame F is a challenging flame if you want to reproduce local extinction. Else it keeps on burning quite well.
3. The model from Pope used a lower temperature to get the local extinction.
4. You may see this recent article on Sandia Flames by our allied group for more details on how flame F should look like.
https://www.sciencedirect.com/scienc...10218021006155

[Lizz4rd]

1) I ran all Configurations from A to F (in the Picture you can see all cases at 7250 s). For the combustion, I use the Jones Lindstedt mechanism.

Chemistry is automatically switched on in the Allrun file:

#!/bin/sh
cd ${0%/*} || exit 1    # Run from this directory

# Source tutorial run functions
. $WM_PROJECT_DIR/bin/tools/RunFunctions

# Set application name
application=$(getApplication)

runApplication chemkinToFoam \
               chemkin/jones_lindstedt.dat chemkin/thermo30.dat chemkin/transportProperties \
               constant/reactionsJL constant/thermo.compressibleGasJL

runApplication -o blockMesh
runApplication -o setFields

# Run the application without chemistry until 1500 to let the flow develop
runApplication -o foamDictionary -entry "startFrom" -set "startTime" system/controlDict
runApplication -a foamDictionary -entry "startTime" -set "0" system/controlDict
runApplication -a foamDictionary -entry "writeInterval" -set "500" system/controlDict
runApplication -a foamDictionary -entry "stopAt" -set "endTime" system/controlDict
runApplication -a foamDictionary -entry "endTime" -set "1500" system/controlDict
runApplication -a foamDictionary -entry "chemistry" -set "off" constant/chemistryProperties

runApplication -o -s "foam" $application

# Run with chemistry until flame reach its full size
runApplication -a foamDictionary -entry "startFrom" -set "latestTime" system/controlDict
runApplication -a foamDictionary -entry "writeInterval" -set "250" system/controlDict
runApplication -a foamDictionary -entry "endTime" -set "7250" system/controlDict
runApplication -a foamDictionary -entry "chemistry" -set "on" constant/chemistryProperties

runApplication -a -s "foam" $application

For all the cases, the composition of the mixture is the same:
Jet: 0.1561 CH4, 0.1966 O2, 0.6473 N2
Pilot: 0 CH4, 0.054 O2, 0.7342 N2, 0.1098 CO2, 0.000129 H2, 0.000747 O, 0.0000248 H, 0.0942 H2O, 0.00407 CO, 0.0028 OH
Coflow: 0.77 N2, 0.23 O2


The velocity differs:

Flame Jet Pilot Coflow
A 2.44 - 0.9
B 18.2 6.8 0.9
C 2.44 6.8 0.9
D 2.44 11.4 0.9
E 2.44 17.1 0.9
F 2.44 22.8 0.9

[godfatherBond]

Originally Posted by Lizz4rd

1) I ran all Configurations from A to F (in the Picture you can see all cases at 7250 s). For the combustion, I use the Jones Lindstedt mechanism.

Chemistry is automatically switched on in the Allrun file:

#!/bin/sh
cd ${0%/*} || exit 1    # Run from this directory

# Source tutorial run functions
. $WM_PROJECT_DIR/bin/tools/RunFunctions

# Set application name
application=$(getApplication)

runApplication chemkinToFoam \
               chemkin/jones_lindstedt.dat chemkin/thermo30.dat chemkin/transportProperties \
               constant/reactionsJL constant/thermo.compressibleGasJL

runApplication -o blockMesh
runApplication -o setFields

# Run the application without chemistry until 1500 to let the flow develop
runApplication -o foamDictionary -entry "startFrom" -set "startTime" system/controlDict
runApplication -a foamDictionary -entry "startTime" -set "0" system/controlDict
runApplication -a foamDictionary -entry "writeInterval" -set "500" system/controlDict
runApplication -a foamDictionary -entry "stopAt" -set "endTime" system/controlDict
runApplication -a foamDictionary -entry "endTime" -set "1500" system/controlDict
runApplication -a foamDictionary -entry "chemistry" -set "off" constant/chemistryProperties

runApplication -o -s "foam" $application

# Run with chemistry until flame reach its full size
runApplication -a foamDictionary -entry "startFrom" -set "latestTime" system/controlDict
runApplication -a foamDictionary -entry "writeInterval" -set "250" system/controlDict
runApplication -a foamDictionary -entry "endTime" -set "7250" system/controlDict
runApplication -a foamDictionary -entry "chemistry" -set "on" constant/chemistryProperties

runApplication -a -s "foam" $application

For all the cases, the composition of the mixture is the same:
Jet: 0.1561 CH4, 0.1966 O2, 0.6473 N2
Pilot: 0 CH4, 0.054 O2, 0.7342 N2, 0.1098 CO2, 0.000129 H2, 0.000747 O, 0.0000248 H, 0.0942 H2O, 0.00407 CO, 0.0028 OH
Coflow: 0.77 N2, 0.23 O2


The velocity differs:

Flame Jet Pilot Coflow
A 2.44 - 0.9
B 18.2 6.8 0.9
C 2.44 6.8 0.9
D 2.44 11.4 0.9
E 2.44 17.1 0.9
F 2.44 22.8 0.9

1. Not all information to go ahead, but I guess it has something to do with the temporal discretization scheme.
2. I never ran a steady state solver for combustion, so cannot comment on that. But from the results the low Re flames are burning. So, D-F do not burn??
Also, whats going on with Flame A??
3. Can you change the temporal discretization to switch to URANS??
ddtSchemes
{
default localEuler;
}


to



ddtSchemes
{
defaultbackward;
}

[Lizz4rd]

Hi, thank you for the suggestion.
Sadly, when switching default backward, I didn't get a solution because the temperature was out of bound.

--> FOAM Warning :
From function Foam::scalar Foam::janafThermo<EquationOfState>::limit(Foam::sc alar) const [with EquationOfState = Foam:erfectGas<Foam::specie>; Foam::scalar = double]
in file /home/ubuntu/OpenFOAM/OpenFOAM-11/src/thermophysicalModels/specie/lnInclude/janafThermoI.H at line 117
attempt to use janafThermo<EquationOfState> out of temperature range 250 -> 3000; T = 1.475681464e+24

When I'm switching to the Gri_mech 3.0 mechanism, who is used in the tutorial, the D-Flame works. But flames A and F still dont work.


With flame configuration A, I generally don't understand how this flame is supposed to burn without a coflame.