CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > ANSYS > FLUENT

Flamelet Parameters

Register Blogs Members List Search Today's Posts Mark Forums Read

Like Tree1Likes
  • 1 Post By kingpots

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   January 23, 2012, 05:34
Default Flamelet Parameters
  #1
New Member
 
Andre Novgorodcev
Join Date: Jan 2012
Posts: 3
Rep Power: 14
andre9 is on a distinguished road
I'm starting to make reactive simulations using Steady Flamelet models. My objective is to simulate a hydrogen flame in air in a tipical bluff-body configuration. I'm using the Burke 2011 kinetic model (8 species + inerts and 19 reactions).

There is any golden rule to determine the following parameters to calculate the flamelet and generate the pdf table?
  • Number of Grid Points in Flamelet
  • Maximum Number of Flamelets

  • Number of Mean Mixture Fraction Points


  • Number of Mixture Fraction Variance Points



andre9 is offline   Reply With Quote

Old   May 20, 2012, 06:28
Default
  #2
New Member
 
Fariborz Soroush
Join Date: Oct 2009
Location: Tehran, Iran
Posts: 14
Rep Power: 16
faudiS8 is on a distinguished road
hi every body
is there anyone here to answer the question?
It's mine too!
Also I want to know if there's any optimum under-relaxations?
My model convergence has many fluctuations.
faudiS8 is offline   Reply With Quote

Old   November 19, 2012, 16:23
Default
  #3
New Member
 
Mina
Join Date: May 2012
Posts: 14
Rep Power: 14
kingpots is on a distinguished road
Hi all ,
As far as i know there isn't any golden rule , however you can validate your results by looking to the Flamelet shape, species , scalar dissipation and mixture fractions .
I am always using the automated refinement with 8 to 40 points /20 flamelets and it gives good results . Check also the time vs . residuels while creating flamletes ,if it is smooth then you are good to go , if on the other hand it takes long time , try to redude the fourrier no. to 1 .
tariq likes this.
kingpots is offline   Reply With Quote

Old   September 8, 2018, 12:27
Default
  #4
New Member
 
tariq's Avatar
 
Tariq Ridwan
Join Date: Jun 2013
Location: Barcelona
Posts: 17
Rep Power: 13
tariq is on a distinguished road
Hi Kingpots,

thank you very much for your response, it was really helpful.

Could you shade some light in solving my simulation, please??

I am doing a non-premixed Methane-air combustion which has swirling air-flow involved. I am using both GRI-mech 3.0 and GRI-mech 2.11 chemical kinetics mechanism and using Steady Diffusion Flamelet chemistry model in Fluent non-premixed combustion. Standard k-epsilon Turbulence model and P-1 radiation model is used.

Simulation Results of Velocity and Gas mass-fraction are matching the experimental data in all locations except gas mass-fraction data in two initial upstream locations. In order to get better gas mass-fraction data, I was trying to figure out a way.

I also always used Automated Grid Refinement.

Now the question is, changing (increasing/decreasing) following default values will give better result ??

1) Maximum number of flamelets (default value: 8)

2) How about Initial Scalar Dissipation (default: 0.01)
and Scalar Dissipation Step (default: 5)?

3) Initial number of Grid points in Flamelet- 8 and
Maximum number of Grid points in Flamelet- 64

4) Maximum Change in Value Ratio- 0.5

5) Maximum Change in Slope Ratio- 0.5


I'm attaching the Fluent Flamelet window screenshot as well.

Could you please help me out??
Attached Images
File Type: png Flamelet Calculation.PNG (107.1 KB, 46 views)
__________________
tariqridwan.github.io/
tariq is offline   Reply With Quote

Old   December 3, 2019, 06:46
Unhappy
  #5
Member
 
samm
Join Date: Feb 2019
Location: South Korea
Posts: 39
Rep Power: 7
Jegan is on a distinguished road
Hi all,
Error while creating flamelet.
Anyone can explain how to use steady diffusion flamelet non-premixed model.

Thanks in advance.
Jegan is offline   Reply With Quote

Reply

Tags
flamelet, flamelet table

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Problems with the unsteady flamelet Model Christoph_84 FLUENT 2 April 24, 2015 16:20
Flamelet gives faster chemistry than ED-model champshof FLUENT 0 November 30, 2011 10:01
units of geometrical parameters lost SoobY ANSYS Meshing & Geometry 2 January 10, 2011 03:58
Error with the unsteady flamelet Model Christoph_84 FLUENT 0 February 25, 2010 11:06
New to CFX-need explanations about mesh parameters Cyril CFX 3 November 24, 2006 06:33


All times are GMT -4. The time now is 10:34.