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-   -   eddy break-up artificial flames (http://www.cfd-online.com/Forums/fluent/43685-eddy-break-up-artificial-flames.html)

Hugo February 9, 2007 10:16

eddy break-up artificial flames
 
Hello Users,

I'm using Fluet to model wood combustion, with the eddy dissipation model for gaseous combustion HOWEVER I get flames in all the wrong places - at the edges of bluff bodies, not above the wood pile. the CFD Wiki (http://www.cfd-online.com/Wiki/Combustion) says that this is a known problem for eddy break-up models and some packeges have a way round it... but gives no details! Can anyone advise?

Thanks, Hugh.

Dmitriy February 9, 2007 16:53

Re: eddy break-up artificial flames
 
Hi Hugh,

Just a suggestion (one of many possible reasons, not necessarily correct in your particular case): is your combustion regime is "well ventilated"? i.e. is it enough oxygen around your wood pile for flame to appear there? I think I saw simulations of diffusion combustion with EBU model (but different from FLUENT CFD code) showing flame not at the fuel source (in a room), but where oxygen is available (behind window openings).

Regards,

Dmitriy


Hugo February 12, 2007 05:51

Re: eddy break-up artificial flames
 
Hi Dmitriy,

Yes, it is well ventilated - air coming up thorugh a bed of wood, which is devolatilising. There is a small flame at teh edge of the first piece of wood, then far far away at the trailing edge of a lip at the outlet, but not directly above teh wood as you would expect.

Still confused! Hugo.

Dmitriy February 12, 2007 08:19

Re: eddy break-up artificial flames
 
Hugo, Sorry then - no clue. Dmitriy


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