I want to patch a small region in flow with high temperature 4000K(because I want to ignite the combustion),but I do not know how to do. patch is effected in a "zone" in FLUENT, I don't know if I can define a new "zone" in FLUENT. I tried to define a small zone in GAMBIT(this zone is surrounded by flow), however, when I export the mesh file, the boundary of the small "zone" are defined as "wall" automatically

From Fluent you go to for example iso-value and mark a region for exampe with Xmin<X<Xmax Then in the patch menu you will choose this region to patch.

Thank you. now I can patch a temperature in a small point using a udf macro "define_adjust" or "define_initial" but for ignite the flow, it's not enough. we have to give a mass fraction of production for this point. I don't know how to do it.

Let me resay it. Because i was not clear. Go to Adapt->Region. Define Xmin-Xmax,Ymin-Ymax,Zmin-Zmax. And click Mark. This way you define a hexaedro in your field. Then go to Patch. Select the value you want to patch (for example gas temperature,or mass fraction of products) and then don't select fluid (from Zones to patch) but your hexaedron (from registers to patch). Patch will be applied only in your hexaedron.

Thank you very mush. I got it

[j.eduardo]

I'm trying to ignite combustion too. I'm doing a region like you sugsted, and then patch with the value of temperature of 1500 k, but it is not working.

Any advice?