Strange Flamelet Generation Problem

August 27, 2007, 06:19

Hello there,

I've got a question concerning the flamelet generation with fluent. I've encountered a strange problem. I wanted to generate a flamelet with a pretty high scalar dissipation rate and a pretty low one. Just to compare. But comparing the temperature profiles and species profiles, I realized that there is no difference at all. I've checked this with different scalar dissipation rates and everytime I get the same result. I restarted fluent, I reread the GRI 2.11 mechanism and all the usual stuff you try, when you encounter a problem like this. But everytime the same result. Did anybody already have similar problems? If so, perhaps you could offer me advice for my strange problem.

Greetings, tar

August 30, 2007, 06:02

Hi,

I just looked at some flamelet tables, i.e. temperature in the mixture fraction space, in the common literature. And I realized, that the max. temperature declines pretty fast as the scalar dissipation rate rises. But when creating this libraries with fluent there is only a real influence when I go to really high scalar dissipation rates far beyond the quenching dissipation rate normally encountered. Did anybody already have similar problems? If so, plz help. I'm using GRI 3.0 mech. Perhaps my setup for the flamelet generation in fluent is wrong?

Greetings, tar.

pghoseju · February 2, 2013, 07:25

Hi,
I am working with non-premixed model with the fuel C12H23.
How can create flamelet for steady flamelet model?
Is there CHEMKIN database in fluent 13.?

Please answer

msaeedsadeghi · February 3, 2013, 05:21

Quote:

Originally Posted by pghoseju

Hi,
I am working with non-premixed model with the fuel C12H23.
How can create flamelet for steady flamelet model?
Is there CHEMKIN database in fluent 13.?

Please answer

No, it is not. You should make a chemkin file in the software then import in fluent.

pghoseju · February 6, 2013, 04:02

Sir, so many thanks to you for yor kind response.
When I am selecting steady flamelet, it asks 2 options
1.create flamelet
2. Import flamelet

a. In create flamlet again there is an option import chemkin mechanissm
b. For boundary , oxidiser as well as fuel mass fraction input options are not highlighted.
c. PDF table can not be generated.

So can you please tell me how to create flamelet?
Thank you.

msaeedsadeghi · February 8, 2013, 10:11

In create flamelet option you can import chemkin mechanism. I will check it in a proper time.

pghoseju · February 9, 2013, 01:13

Thank you sir,
In fluent chemkin is there? I am not able to find. If it is there, can you say in which directory and folder it is there? It is very urgent to me sir. Thank you again

msaeedsadeghi · February 9, 2013, 02:38

There is an option in the non-premixed menu after selecting steady flamelet. You can choose "Import Chemkin Mechanism", then create Flamelet.

pghoseju · February 12, 2013, 02:36

Yes sir,
Everything is true, but when I am clicking 'Import CHEMKIN mechanism'. Next option: it is asking for 'Gas-phase CHEMKIN mechanisinm file'

Now my problem is where is the Gas-phase CHEMKIN mechanisinm file?
Is it some where in my computer? if yes where is it?
Again i want to ask you whether chemkin is inbuilt Ansys13.0 (licenced)? or separately we have to purchase it?

msaeedsadeghi · February 12, 2013, 02:39

haha.
You should separately purchase it. CHEMKIN is an independent program that makes mechanisms.

pghoseju · February 13, 2013, 01:09

Thank you.
Yes, Now I am clear.

Sudharsan · March 22, 2014, 11:52

Hi everyone,

I trying simulate a unsteady liquid combustion in fluent. Actually I'm starting the simulation with a case which was previously used for gas combustion. For gas combustion it gave good results. For liquid combustion I'm tried with heptane. I downloaded the flamelet mechanism for heptane. When try create chemkin for my problem it (fluent) shows access violation error. Please help me in this regard.

August 27, 2007, 06:19	Strange Flamelet Generation Problem	#1
tar Guest Posts: n/a	Hello there, I've got a question concerning the flamelet generation with fluent. I've encountered a strange problem. I wanted to generate a flamelet with a pretty high scalar dissipation rate and a pretty low one. Just to compare. But comparing the temperature profiles and species profiles, I realized that there is no difference at all. I've checked this with different scalar dissipation rates and everytime I get the same result. I restarted fluent, I reread the GRI 2.11 mechanism and all the usual stuff you try, when you encounter a problem like this. But everytime the same result. Did anybody already have similar problems? If so, perhaps you could offer me advice for my strange problem. Greetings, tar

August 30, 2007, 06:02	Re: Strange Flamelet Generation Problem	#2
tar Guest Posts: n/a	Hi, I just looked at some flamelet tables, i.e. temperature in the mixture fraction space, in the common literature. And I realized, that the max. temperature declines pretty fast as the scalar dissipation rate rises. But when creating this libraries with fluent there is only a real influence when I go to really high scalar dissipation rates far beyond the quenching dissipation rate normally encountered. Did anybody already have similar problems? If so, plz help. I'm using GRI 3.0 mech. Perhaps my setup for the flamelet generation in fluent is wrong? Greetings, tar.

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February 2, 2013, 07:25		#3
pghoseju Member Prakash Ghose Join Date: Dec 2011 Posts: 34 Rep Power: 15	Hi, I am working with non-premixed model with the fuel C12H23. How can create flamelet for steady flamelet model? Is there CHEMKIN database in fluent 13.? Please answer

February 6, 2013, 04:02		#5
pghoseju Member Prakash Ghose Join Date: Dec 2011 Posts: 34 Rep Power: 15	Sir, so many thanks to you for yor kind response. When I am selecting steady flamelet, it asks 2 options 1.create flamelet 2. Import flamelet a. In create flamlet again there is an option import chemkin mechanissm b. For boundary , oxidiser as well as fuel mass fraction input options are not highlighted. c. PDF table can not be generated. So can you please tell me how to create flamelet? Thank you.

February 8, 2013, 10:11		#6
msaeedsadeghi Senior Member SSL Join Date: Oct 2012 Posts: 226 Rep Power: 15	In create flamelet option you can import chemkin mechanism. I will check it in a proper time.

February 9, 2013, 01:13		#7
pghoseju Member Prakash Ghose Join Date: Dec 2011 Posts: 34 Rep Power: 15	Thank you sir, In fluent chemkin is there? I am not able to find. If it is there, can you say in which directory and folder it is there? It is very urgent to me sir. Thank you again

February 9, 2013, 02:38		#8
msaeedsadeghi Senior Member SSL Join Date: Oct 2012 Posts: 226 Rep Power: 15	There is an option in the non-premixed menu after selecting steady flamelet. You can choose "Import Chemkin Mechanism", then create Flamelet.

February 12, 2013, 02:36		#9
pghoseju Member Prakash Ghose Join Date: Dec 2011 Posts: 34 Rep Power: 15	Yes sir, Everything is true, but when I am clicking 'Import CHEMKIN mechanism'. Next option: it is asking for 'Gas-phase CHEMKIN mechanisinm file' Now my problem is where is the Gas-phase CHEMKIN mechanisinm file? Is it some where in my computer? if yes where is it? Again i want to ask you whether chemkin is inbuilt Ansys13.0 (licenced)? or separately we have to purchase it?

February 12, 2013, 02:39		#10
msaeedsadeghi Senior Member SSL Join Date: Oct 2012 Posts: 226 Rep Power: 15	haha. You should separately purchase it. CHEMKIN is an independent program that makes mechanisms.

February 13, 2013, 01:09		#11
pghoseju Member Prakash Ghose Join Date: Dec 2011 Posts: 34 Rep Power: 15	Thank you. Yes, Now I am clear.

March 22, 2014, 11:52		#12
Sudharsan New Member Sudharsan Join Date: Mar 2014 Posts: 3 Rep Power: 12	Hi everyone, I trying simulate a unsteady liquid combustion in fluent. Actually I'm starting the simulation with a case which was previously used for gas combustion. For gas combustion it gave good results. For liquid combustion I'm tried with heptane. I downloaded the flamelet mechanism for heptane. When try create chemkin for my problem it (fluent) shows access violation error. Please help me in this regard.