Learning Forum

[John Patton]

Hi everyone, was hoping someone could help guide me in the right direction with this problem.

I am designing a ramjet geometry using matlab but I want to model it in Fluent as well. Preferably tip to tail but if I need to break up the sections its fine. However, we are supposed to model the Flameholder section as a pressure loss according to this formula: 

 

This pressure loss region would be at the line marked "3" in the picture below.

Modeling this is matlab is straightforward but in Fluent is another matter. I am confident in how to model all the other sections but am at a bit of a loss on how to model this pressure loss. This would be a 2D simulation so the pressure loss would be a straight line across the combustor region. I've seen a few things regarding using the porous media model/tool thing as a potential solution but I am not confident in that approach. 

Any help/advice/guidance would be appreciated. Thank you!

[Rob]

You may want to look at 2d axi-symmetric rather than just 2d, but I'll leave that for you to decide. 

Porous Jump (surface) or Porous Media (volume) are the two pressure loss options. They both use resistance coefficients so may or may not give you want you need given the above formula: the theory is covered in the Fluent User's Guide, clicking Help in Fluent will get you there. 

[John Patton]

Thank you! I'll dive into the user guide and see if I can make the porous options work for me. I'll reply again if I run into any issues.