need help on Sublimation
 

Hi guys

I am doing solid urea injection into boiler but I don't know how to set sublimation rate. There should be some place for it in FLUENT (as its help says) but I can't find it. Any one has any helpful idea?

Thanks

It's like solid fuel combustion. The rate can be entered into material properties of the combusting particle.

Thanks for your reply. To be more specific, I am working on solid urea injection. There is no "solid urea" in FLUENT material database and I needed to add it. The problem is that there is no "sublimation rate" in the properties required to define a new solid material. On the other hand, there is "solid urea" in "inert particle type" of DPM but I don't know if FLUENT has defined some default properties for it or not. Here is what I did:
1- I defined new material, solid urea, in material section; however, I didn't find any place to enter sublimation rate.
2- I selected "urea-solid" in Material drop-down list in DPM (inert) and set all the required parts. I should mention that urea-solid" is different from "solid urea" that I already defined. It exist regardless of defining any new material.
3- Then I ran it with my combustion case but what I finally got is a stream of solid particles that move along a pathline and leave my boiler.There is no change in their size (and consequently no sublimation!).

I think now you understand my problem. Even if you don't have any experience with urea injection, you could assume it as a new solid particle that is going to burn. How should I set the combustion properties and force FLUENT to assume it as a fuel and not just a particle. In case of a new solid fuel (it could be a new biomass) there should be some place to define the devolatilization properties or ask FLUENT to consider devolatilization.

I am looking forward to getting your help.
Thanks a lot.