VOF 2D Axisymmetric Swirl Simulation - Volume Fraction does not change

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  • Last Post 20 April 2020
guilhermemd11 posted this 20 April 2020

Hello,

I am a newcomer to Ansys Volume of Fluid simulations, so I will appreciate any help!

I am currently trying to simulate, using transient VOF, a 2D Axisymmetric model of a Pressure Swirl Injector. In this type of injector, the fluid enters through a number of tangential inlet ports (an image of the CAD of the injector is attached for better visualization). A PNG of the 2D Axisymmetric model is also attached, with inlet, outlet, walls and axis pointed out.

 

 

 I followed the Ansys Tutorial Guide (version 18.0) for both an axisymmetric flow and for VOF Modelling. I also tried to mimic the procedure from several scientific papers I read.

What I am trying to obtain is something similar to this simulation:

The problem I am facing is that, when I calculate the posed problem, the volume fraction remains unchanged. To check if the problem was in the set up, I changed the solver from Axysimmetric Swirl to only Axysimmetric and changed the inlet boundary condition to axial velocity only, and it seems to have worked (even though the new simulation had nothing to do with the original problem).

I believe the problem may be with the velocity inlet boundary condition I used (also attached as a PNG image). Or maybe with the boundary per se (I defined it as an edge). I am not sure. I would like some insight, especially if some of you have already worked with a similar problem.

 Thanks in advance

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abenhadj posted this 20 April 2020

What about the axial component?

Best regards, Amine

guilhermemd11 posted this 20 April 2020

Hi Amine, thanks for the reply!

So, from what I have read on the scientific literature, in a pressure-swirl (simplex) atomizer, the fluid enters the spin chamber with tangential velocity only (theoretically). The axial velocity would come due to a pressure difference (between the spin chamber and the oulet) created by the vortex. Therefore I don't know how I would consider an axial component on the inlet. Do you have any ideas?

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