Learning Forum

[Weiqiang Liu]

Hi all,

I am modeling a porous soot cake combustion with fluent. The case is transient and local soot concentration is considered as an UDS. I almost get everything right except Y velocity contour for my case.

In order to debug my model, I tried a lot of methods. One of these was to add an momentum source for the generated mass source. Because my problem is Y velocity in porous zone is too small, I think a momentum source could accelerate gas in porous zone. However, it seems no difference whether momentum source is included or not. Therefore, I think maybe my momentum source was added in the wrong way.

For specific, I defined momentum source for mass source in the following way:

x momentum source=mass source*cell volume*x velocity

y momentum source=mass source*cell volume*y velocity

I am wondering did I define momentum source in the right way? Because if I do some dimension analysis, I found the unit is different in two sides of the equation. 

My question is do I need to integrate the momentum term during time step? or how should I define my momentum term for mass source?

Best regards

Weiqiang