Hi, I am working with CFD to analyze a swirling burner with a square section combustor. When I calculate the angular and the axial momentum inside the combustor, it decreases the more I check downstream to the burner exit. Do you know what would create a decrease in the angular and axial momentum inside a square section combustor? Should the swirl number variate inside the combustor?

Thank you very much for your help.

Hi,

Some possible causes: Viscous drag at the walls, turbulence generation, separations causing losses, inaccurate simulation.

Glenn Horrocks

Thanks for your answer. Do you know some references about it or how they are modifing the momentum?

Thanks again for your help.

Hi,

Look in the literature for swirling flows, such as cyclone separators. For modelling accuracy issues read the documentation or for more detail see Roache's book "Computational Fluid Dynamics".

Glenn Horrocks