Hi,

How can I define different surface reactions at different walls by UDF. Thanks.

Jason

I have not done this so I don't know if I am fully qualified to answer this question. But as noone else answered I thought I would hav a go. You can put a conditional statment into a DEFINE_SR_RATE macro something like:

if (!strcmp(r->name, "reaction-1")) {*rr = whatever you want;}

Where reaction-1 is the reaction ID in the reaction panel in the GUI. you can then select what reactions you want in the mechanisms panel and then you can set what mechanism you want on each reaction boundary. This is assuming you are on Fluent 6 - if not you should get it because it is very good for reaction modelling. I have not done this myself so let me know if it works out because I would be interested in finding out.

Thanks. Your method will work on multiple reactions. But I want different reaction on different wall. For examples, only reaction 1 on wall A, reaction 2 and 3 on wall B, and so on. Maybe Fluent does not have this function.

Thanks again.

using your example, could you not select reaction 1 to be in mechanism 1 and reactions 2 and 3 to be mechanism 2,then apply mechanism 1 to wall A and mechanism 2 to wall B?

I can not find mechanism panel as you said. I'm using Fluent 6.0. In the wall panel of "defining BC", I can just select "surface reaction" in "Species". In the reaction panel of "material", I must define all 3 reactions there, and can not separate them by mechanism as you said.

Thanks

define->materials->Material Type:mixture->mechanisms.

Hi, Andrew,

What version of Fluent you are using? I do not have thsi option. I'm modeling a laminar flow with 3 wall reactions. In Material panel, I can not find this option. Here is a manual I'm also reading. http://p2chpd-cluster.univ-lyon1.fr/...g/node1059.htm

There is also no mechanism selection description. Thanks

I am using 6.1.18. Maybe the mechanisms panel is not avaliable in 6.0. I assumed that it would be. I had a look in the fluent6.1 manual and there is a section in the index called reaction mechanisms. I looked in your manual and it is not there. I suggest getting Fluent 6.1. I don't know if there is a way of doing what you want without the reaction mechanisms panel, I would expect there would be, but I don't know how to do it. I would suggest the easiest soultion is to get 6.1.22 (which is the latest one) from the fluentusers website.