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TedBrogan November 9, 2010 14:58

Annular Flow Using VOF

I'm running into difficulty getting any sort of annular flow simulation using VOF to work in FLUENT. It's usually divergence in AMG solver or other fatal errors. I can run the simulations using VOF from the tutorials, but none of those give much detail on setting up an annular flow. Any comments or help is much appreciated. Ideally, a working case file for an annular flow or something similar that I can build from would be great.

Thank you,

TedBrogan March 7, 2011 12:14

For reference for others in the future, here are some self-discovered tips for this type of scenario.

Have two separate inlets, one with all gas flow and one with all liquid flow. I've been using either mass flow or pressure inlets for the liquid and pressure inlet for the gas. The outlet is a pressure outlet. PISO and SIMPLE solvers have worked well for my transient simulations. I believe PISO is better for transient and SIMPLE for compressible so compromise has to be made. For initial convergence problems, I've found it helpful to turn off the energy equation initially and use very small iterations per time step (5-10) until the solution is more stable. You can get around that for a given geometry down the road once you have a decent solution by using interpolation as a starting point.

Anf893 May 3, 2011 17:56

I'm trying to do a simulation of annular flow through a pipe, I'm pretty lost, can you help me?

TedBrogan May 10, 2011 11:38

I never actually did pipe flow. It was nozzle flow, and I was just trying to start with a problem I hoped more people would have experience with. The tips I listed in the previous post were everything I was able to learn. You might try to repeat someone else's simulation as a starting point. I think I looked at:

Han, H., Gabriel, K., "A Numerical Study of Entrainment Mechanism in Axisymmetric Annular Gas-Liquid Flow," Journal of Fluids Engineering, Vol. 129, March 2007.

Good luck!

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