CFD Online Logo CFD Online URL
Home > Forums > General Forums > Main CFD Forum

case files UDF volumetric reaction rate

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

LinkBack Thread Tools Search this Thread Display Modes
Old   February 14, 2006, 10:16
Default case files UDF volumetric reaction rate
Posts: n/a
Good Morning,

I am working on chemical reaction (graphite oxidation and CO combustion at aproximately 800 C ) in FLUENT. I need to build a UDF because the reaction rates don't follow at all the Arrhenius law. However, I have never programmed in C before. I would apreciate very much if someone could send me examples of UDF for Define_sr_rate or Define_vr_rate. Any comment on how the UDF actually modifies the rate first computed using the Arrhenius model would be more than welcome.

Thanks, Marie-Anne
  Reply With Quote

Old   February 20, 2006, 01:33
Default Re: case files UDF volumetric reaction rate
Posts: n/a
In fluent, chemical reactions particulary the combustion reactions are modelled by: 1. Arrehnius law: for reaction kinetic controlled reactions 2. Eddy Dissipation Model: for gaseous reactions controlled by turbulence mixing

Therefore, it has got one algorithm called EDC, eddy dissipation concept where it calculates reactions from both the models and take the minimum of both the values.

** more UDF on reaction rates ...... go to fluent documentation and then UDF section .... u will get some standard UDFs, which u can copy and then modify cells, threads etc according your problem to hook-up it.

Plz do write whether it helped you or not ?
  Reply With Quote

Old   February 24, 2006, 09:43
Default Re: case files UDF volumetric reaction rate
Posts: n/a
Hey Kumar,

Sorry for not answering sooner, but I was out of office. Thank you for your answer. My problem is more that I don't really know how to program, but I am trying to use exemples from the UDF manual. I am having right now a floating point error message. If you have any idea where that might come from...


  Reply With Quote


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
HELP----Surface Reaction UDF Ashi Fluent UDF and Scheme Programming 1 May 19, 2020 21:13
using rate equation for volumetric reaction byronsmith FLUENT 4 April 14, 2019 12:28
Error with Volumetric reaction UDF elmcmaster FLUENT 0 October 21, 2010 07:18
Free surface boudary conditions with SOLA-VOF Fan Main CFD Forum 10 September 9, 2006 12:24
surface reaction rate zhou FLUENT 4 October 2, 2003 16:16

All times are GMT -4. The time now is 23:47.