CFD Online Discussion Forums

CFD Online Discussion Forums (
-   FLUENT (
-   -   FLUENT and CHEMKIN mechanism (

diamondx July 5, 2012 11:06

FLUENT and CHEMKIN mechanism
Hello ,
i have a question , Can fluent read Chemkin mechanism input files (i.e ext.inp ) or it has to be (ext. che ) .

aerospace1365 July 6, 2012 11:30

yes u can. import it from file-import-chemkine

diamondx July 6, 2012 11:36

thanks for your reply.
does it support .inp extension or only valid for .che, coz i am getting an error msg while importing it as a .inp file .

aerospace1365 July 6, 2012 14:25

dear ali what is your error about. can you write it.

diamondx July 6, 2012 14:37

1 Attachment(s)
Hi ,

the msg is unexpected error , 1 , line 17 and line 37 .
i have attached the file .inp (which represents the mechanisms and the Thermo. property files ) . if u can have a look and try to let it work ill be graceful
thanks .

Ivanesus July 10, 2012 10:30

Fluent can use no more than 50 elements. All elements in reactions should correspond to the list in thermodynamic data. Correct the keywords. For example:
---------------- in file termo.db --------------------------
H L 6/94C 0H 1N 0O 0G 0300.00 6000.00 1000.00 1
2.5000000E+000 0.0000000E+000 0.0000000E+000 0.0000000E+000 0.0000000E+000 2
2.5473660E+004-4.4668285E-001 2.5000000E+000 0.0000000E+000 0.0000000E+000 3
0.0000000E+000 0.0000000E+000 2.5473660E+004-4.4668285E-001 2.6219035E+004 4
H2 RUS 78C 0H 2N 0O 0G 0300.00 6000.00 1000.00 1
2.9328305E+000 8.2659802E-004-1.4640057E-007 1.5409851E-011-6.8879615E-016 2
-8.1305582E+002-1.0243164E+000 2.3443029E+000 7.9804248E-003-1.9477917E-005 3
2.0156967E-008-7.3760289E-012-9.1792413E+002 6.8300218E-001 0.0000000E+000 4
O L 1/90C 0H 0N 0O 1G 0300.00 6000.00 1000.00 1
2.5436370E+000-2.7316249E-005-4.1902952E-009 4.9548185E-012-4.7955369E-016 2
2.9226012E+004 4.9222946E+000 3.1682671E+000-3.2793188E-003 6.6430640E-006 3
-6.1280662E-009 2.1126597E-012 2.9122259E+004 2.0519335E+000 2.9968701E+004 4
OH IU3/03C 0H 1N 0O 1G 0300.00 6000.00 1000.00 1
2.8385303E+000 1.1074129E-003-2.9400021E-007 4.2069873E-011-2.4228989E-015 2
3.6978081E+003 5.8449465E+000 3.9919842E+000-2.4010665E-003 4.6166403E-006 3
-3.8791631E-009 1.3631950E-012 3.3688984E+003-1.0399848E-001 4.4861538E+003 4
------------- in file reactions.mec ---------------
O+H2=OH+H 5.13E+004 2.67 6290.0
------------- in file transport.db --------------------
H 0 145.000 2.050 0.000 0.000 0.000
H2 1 38.000 2.920 0.000 0.790 280.000
O 0 80.000 2.750 0.000 0.000 0.000
O2 1 107.400 3.458 0.000 1.600 3.800
OH 1 80.000 2.750 0.000 0.000 0.000

Council - look for the reduced mechanism for the task if only you aren't engaged in studying of formation of any element in detail. The mechanism given by you will be too expensive for calculation CFD.

nidhitw September 8, 2013 07:57

LPG chemkin file

I am working on a problem with LPG +air mixture. Does anybody have chemkin file for LPG ?


sanjeetlimbu April 13, 2015 17:47

1 Attachment(s)
Dear sir

i am trying the same work , using aLiu mechanism- 43 species but the file i got is showing error when i try load to PDF create box for line numder 4 in chemkin .che and some line in .db thermal file

I have attached the mechnaism mother file as txtx and the thermal , chemicak kinetc , trans file i seperated from that . but still it shows some error.
Though i used it in chemkin i worked there

Can u please share me by checking the fault lines... at

chittipo April 14, 2015 04:48

1 Attachment(s)
Hi this may be ^M issue at the end of some lines and starting of empty lines. you could delete this character in vi editor if you are in linux. google it how can you delete this character :)
some suggestions: why do you use spaces in file name? please use proper editor to open these files in windows.

can you try now the attached, I have deleted this character for you now.

Attachment 38657

sanjeetlimbu April 20, 2015 12:23

2 Attachment(s)
Hi I am trying to use the chemkin file for nheptane Liu mechanism .. I added the Argon in this to get the results for my mixture - partially premised commbustion of N2/Ar/O2/nC7H16: 58/30/10.307/0.00562 by mole fraction .

I updated the .che and .db files for upload and creating pdf in species dialog box..
Got the error can u see my file and tell corrections needed ..

I am doing the compression and post compressed ignition after 30 millisec

chittipo April 21, 2015 02:39

As of now this is not an error. For all the missing species Fluent sets constant property evaluation (it appears so). You need to input this constant value in respective property terminal for thermal counductivity and viscosity.

why and how to avoid these messages:
it means, either you do not have the species listed on Fluent terminal (ph.../px2...) in your *.db file or Fluent failed to ready due to some error in the *.db file. Can you check whether all the species listed in your *.che are available in *.db file. You probably have them for Cp evaluation in therm.db file and do not have them in transport data base file.

Do not worry if you do not have them in transport data base, as you see Fluent set to constant property in that case. But make sure you enter approximate right value for it.

sanjeetlimbu April 22, 2015 18:52

5 Attachment(s)
Dear sir
I am unable to get the compression stroke in closed system to make temperature rise.. but pressure rise. It is 2D axisymetric case
Can U suggest reason

I feel I am not having the initialisation values correct... or some thing in species model is missing for compression

All times are GMT -4. The time now is 01:27.