CFD Online Discussion Forums

CFD Online Discussion Forums (http://www.cfd-online.com/Forums/)
-   FLUENT (http://www.cfd-online.com/Forums/fluent/)
-   -   need help on Sublimation (http://www.cfd-online.com/Forums/fluent/105325-need-help-sublimation.html)

BMCombustor July 27, 2012 13:27

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

eng_s_sadeghi July 28, 2012 06:38

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

BMCombustor July 30, 2012 11:19

Quote:

Originally Posted by eng_s_sadeghi (Post 374090)
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.


All times are GMT -4. The time now is 18:01.