reduced version of GRI 3.0 Mechanism

buxtsued · July 5, 2011, 16:20

I wish to simulate a combustion in Fluent 13.0 with the "gri 3.0"-mechanism. After importing it in chemkin format (with the appropriate thermo.dat) and setting to pdf transport model, there appears a message "Maximum of 50 solved species allowed. Use Dimension Reduction instead." (gri 3.0 has 53 spesies). I have tried to reduce the number of spesies to 50 using the "Dimension Reduction" option (choosing out varios three spesies from the list "i wish not to take part"), but it doesn't work, nevertheless. In the 'Spesies Model' dialog box the number of volumetric spesies can be seen under "reduced-dimension-mixture", which remains 53 (in spite of using the dimension reduction option).
Do anybody know how to use a 50-species (e.g. reduced) version of GRI-Mech 3.0 in Fluent???

Thanks, buxtsued

Mica · July 13, 2011, 05:41

Hey buxtsued,

I'm working with a reduced Grimech mechanism. DO the following:
Open the chemkin-file you want to import in any text-editor. You can quote out the following information in a line by "!" (As done in the header)
Quote out or delete the most abundant species. In my case these are AR C3H7 and C3H8. Remember to quote out AR in the elements list too.
Search all reactions containig these species and quote them out. You can also reorder your species and set N2 at the last place. This is appropriate for combustion in air, then you dont have to specify the fraction of N2 in Fluent, since it is just the rest.

Greetings,
mic

buxtsued · July 13, 2011, 20:47

Hi Mica,
i have tried to do so, but there is still the same problem. Did you use the "Dimension Reduction" function after importing your modified chemkin mechanism?
Maybe i didnt modify the gri3.0-file correctly. Could you eventually send me your modified mechanism?

BR

Mica · July 14, 2011, 03:49

Here it is...

buxtsued · July 14, 2011, 12:01

It works. Thanks for your help.

dpfrz · November 21, 2014, 10:33

Hey guys, its crucial that I use GRI 3.0 Mechanism for my simulations but unfortunately I think I will need a CHEMKIN-CFD license to do so in Fluent. Is there another way to do this without a license or even find the license somewhere?

Thank you for your time!

jp279 · July 23, 2015, 09:19

After importing the Chemkin file for mechanism and transport, fluent takes very long for each iteration (Steady State).
Can anyone suggest any speed up criteria where I can avoid solving for a few less important species?
(Currently solving for 50 species)

Weiqiang Liu · August 7, 2018, 10:32

hello,

is the maximum number of species imported in chemkin format is 50? because when I use GRI 2.0, simulation can proceed. however, when GRI 3.0 is used , error occurs at the beginning of calculation.

LuckyTran · August 7, 2018, 13:53

Quote:

Originally Posted by Weiqiang Liu

hello,

is the maximum number of species imported in chemkin format is 50? because when I use GRI 2.0, simulation can proceed. however, when GRI 3.0 is used , error occurs at the beginning of calculation.

Yes. Fluent has a hard-coded limitation of 50 species. Someone at some point decided Fluent should never be used with more than 50 species, which is really annoying considering GRI 3.0 is 53 species. Fluent comes with a 50 species version of GRI 3.0 (AR, C3H8, and C3H7 radical are removed) if you need it.

Weiqiang Liu · August 7, 2018, 15:32

Quote:

Originally Posted by LuckyTran

Yes. Fluent has a hard-coded limitation of 50 species. Someone at some point decided Fluent should never be used with more than 50 species, which is really annoying considering GRI 3.0 is 53 species. Fluent comes with a 50 species version of GRI 3.0 (AR, C3H8, and C3H7 radical are removed) if you need it.

yes, it's really annoying. do you know any other tools or codes that can simulate combustion with mechanism more than 50 species?

LuckyTran · August 7, 2018, 15:36

Quote:

Originally Posted by Weiqiang Liu

yes, it's really annoying. do you know any other tools or codes that can simulate combustion with mechanism more than 50 species?

I only one I have experience with is Star-CCM. OpenFOAM has this capability too, but I haven't used it. But can't you just use the 50species version of gri 3.0? I don't think it's worth learning an entirely new software if that is the only reason.

Weiqiang Liu · August 7, 2018, 15:50

[QUOTE=LuckyTran;701840]I only one I have experience with is Star-CCM. OpenFOAM has this capability too, but I haven't used it. But can't you just use the 50species version of gri 3.0? I don't think it's worth learning an entirely new software if that is the only reason.[/QU

because I wanna simulate diesel combustion which is more complicated than methane. therefore, I wanna use chemkin or some other code which is more efficient for combustion simulation.

July 5, 2011, 16:20	reduced version of GRI 3.0 Mechanism	#1
buxtsued New Member Sergej Join Date: Jun 2011 Posts: 4 Rep Power: 15	I wish to simulate a combustion in Fluent 13.0 with the "gri 3.0"-mechanism. After importing it in chemkin format (with the appropriate thermo.dat) and setting to pdf transport model, there appears a message "Maximum of 50 solved species allowed. Use Dimension Reduction instead." (gri 3.0 has 53 spesies). I have tried to reduce the number of spesies to 50 using the "Dimension Reduction" option (choosing out varios three spesies from the list "i wish not to take part"), but it doesn't work, nevertheless. In the 'Spesies Model' dialog box the number of volumetric spesies can be seen under "reduced-dimension-mixture", which remains 53 (in spite of using the dimension reduction option). Do anybody know how to use a 50-species (e.g. reduced) version of GRI-Mech 3.0 in Fluent??? Thanks, buxtsued

November 21, 2014, 10:33	GRI 3.0 Mechanism	#6
dpfrz New Member Chris Join Date: Nov 2014 Posts: 1 Rep Power: 0	Hey guys, its crucial that I use GRI 3.0 Mechanism for my simulations but unfortunately I think I will need a CHEMKIN-CFD license to do so in Fluent. Is there another way to do this without a license or even find the license somewhere? Thank you for your time!

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July 13, 2011, 05:41		#2
Mica New Member Join Date: Jul 2011 Posts: 5 Rep Power: 15	Hey buxtsued, I'm working with a reduced Grimech mechanism. DO the following: Open the chemkin-file you want to import in any text-editor. You can quote out the following information in a line by "!" (As done in the header) Quote out or delete the most abundant species. In my case these are AR C3H7 and C3H8. Remember to quote out AR in the elements list too. Search all reactions containig these species and quote them out. You can also reorder your species and set N2 at the last place. This is appropriate for combustion in air, then you dont have to specify the fraction of N2 in Fluent, since it is just the rest. Greetings, mic

July 13, 2011, 20:47		#3
buxtsued New Member Sergej Join Date: Jun 2011 Posts: 4 Rep Power: 15	Hi Mica, i have tried to do so, but there is still the same problem. Did you use the "Dimension Reduction" function after importing your modified chemkin mechanism? Maybe i didnt modify the gri3.0-file correctly. Could you eventually send me your modified mechanism? BR

July 14, 2011, 12:01		#5
buxtsued New Member Sergej Join Date: Jun 2011 Posts: 4 Rep Power: 15	It works. Thanks for your help.

July 23, 2015, 09:19		#7
jp279 New Member jp279 Join Date: Jul 2015 Posts: 9 Rep Power: 11	After importing the Chemkin file for mechanism and transport, fluent takes very long for each iteration (Steady State). Can anyone suggest any speed up criteria where I can avoid solving for a few less important species? (Currently solving for 50 species)

August 7, 2018, 10:32		#8
Weiqiang Liu Senior Member Weiqiang Liu Join Date: Feb 2018 Posts: 278 Rep Power: 9	hello, is the maximum number of species imported in chemkin format is 50? because when I use GRI 2.0, simulation can proceed. however, when GRI 3.0 is used , error occurs at the beginning of calculation.

August 7, 2018, 15:50		#12
Weiqiang Liu Senior Member Weiqiang Liu Join Date: Feb 2018 Posts: 278 Rep Power: 9	[QUOTE=LuckyTran;701840]I only one I have experience with is Star-CCM. OpenFOAM has this capability too, but I haven't used it. But can't you just use the 50species version of gri 3.0? I don't think it's worth learning an entirely new software if that is the only reason.[/QU because I wanna simulate diesel combustion which is more complicated than methane. therefore, I wanna use chemkin or some other code which is more efficient for combustion simulation.