Hi, Fluent experts,

Can anyone kindly tell me if Fluent can simulate coal combustion using a model beside the discret phase model? I need to simulate a case in which the coal loading is very high (25% vol). Thanks.

kchen

Hi kchen! I don't have a complete answer to your question and I would be happy if any coal-combustion expert will provide us his knowledge.

I know for sure that you will have to use the Eulerian - Eulerian approach and not the Euler-Lagrange (DPM), due to the high particle loading. I think that with version 6.2, which can incorporate heterogeneous reactions and mass transfer between phases you will be able to solve your problem. But you will probably have to write some UDFs! What is your case exactly?

Ilias

Thanks, HP. I know in the Eulerian model, Fluent can simulate CHAR combustion, but it seems to me that it can NOT simulate coal devolatilization. My case is prety simple, in fact. There are 2 streams: one is carrier gas + coal, and the other is hot air. These two streams mix in a chamber.

In the following paper drying, devolatilization and char combustion are described in an Eulerian (unified) fashion. But am not sure how can you implement these in Fluent. It is one of the things that I have in mind to try in the future (the E-E combustion). So I would appreciated if you kept me notified about your success or not in this case (and if paper helped you at all!).

The paper is:

"Numerical studies of pulverized coal combustion in a tubular coal combustor with slanted oxygen jet", Guo, Chan, Lau - FUEL

Regards,

Ilias

Hi Ilias,

I know in CFX both the E-L and E-E models can be used to simulate coal combustion. But in Fluent, only the E-L model can be used. I will see if I can use UDF to get rid of high solid loading problems.

Even if you try to model your case with E-L (although your volume fraction of the dispersed phase is greater than 10% and it is not valid), it is sure that you will have convergence problems due to the high mass loading (>>1!). So I think that E-E is your only choice.

Now concerning drying and devolatilization, why can't you just consider them as reactions? (did you see the paper I send you?)

Ilias