Wall Reaction in Turbulent flow
 

Hi out there

is there anyone already worked with catalytic reaction system for a fluid in turbulence flow..??? I saw in fluent's users' guide that wall reaction is just can work for laminar flow..

Is that possible to have UDF for wall reaction in turbulence flow..?? I mean anyone have tried it yet..??

Rajab

Re: Wall Reaction in Turbulent flow
 

I haven't used the new Fluent 6 wall reaction, though I have written my own reaction udfs for Fluent 5 and/or 6. However these are essentially the same as those in Fluent 6.

In any case I think you can simulate reactions in a turbulent flow using the built-in scheme. If you fully resolve the b/l etc mass transfer occurs largely due to diffusion at the surface (in laminar-like viscous sublayer). Now in typical calculations you probably wont resolve down to this level of detail, and so the various wall approximations are used - in this case I believe Fluent would replace the molecular diffusivity of each species (Dim) with the effective diffusivity (Di,eff) which is calculated using the various turbulent approx. So there may be a need to take care with the mesh and wall models you choose, but I would expect it to be ok.?

My models use a similar approach and at least for global behaviour give good results - though I haven't done much on the local behaviour. Do you have a good validation case you're thinking of trying?? I'd be interested to check my models and Fluent 6 ones against some detailed experiments for combustion type problems. If you have any refs please post them.

Regards

Greg