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2d pressure swirl atomizer using vof

The problem I am facing is that, when I calculate the posed problem, the volume fraction moves only a few steps and then courant number goes up and error is shown.The left figure shows the result from my simulation and right shows flow i wanted to simulate(from literature).

I believe the problem may be with the velocity inlet boundary condition , I am not sure. I would like some insight, especially if some of you have already worked with a similar problem.

Thank you


OpenFOAM 03-11-20, 11:07 p.m. rrohit2004
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Hi Rohit,

You could try using adjustable time-steps. This way, you can ensure that your solver isn't crashing because of your boundary conditions. Multiphase solvers tend to remain stable for Courant numbers > 1, but not >> 1. Just to be sure, you could set the maximum Courant number (maxCo) to 1 in your controlDict and see how the simulation looks.

Regards,
Ashley

03-11-20, 11:25 p.m. ashleymelvin


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Thanks for reply Ashley I had tried with adjustable time step and keeping maxco 1, but the simulation time step goes beyond 2.3e+12 and error is shown after few seconds. Is it the problem with the mesh or the inlet conditions. Regards, Rohit
04-11-20, 12:06 a.m. rrohit2004

Looks like the problem is with the boundary conditions. Even for the coarsest of mesh, imposing a maxCo should stabilize the simulation, even though the results might not be accurate. Also, for the time-step, did you try a very low value, even if that value is considered in the simulation only for the first time-step?

Regards,
Ashley


04-11-20, 12:12 a.m. ashleymelvin

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From the literature,(figure shows the boundaries) the liquid will enter with a radial and tangential velocity(as a conversion from 3D to 2D). I used swirlFlowRateInletVelocity with radial and tangential velocity as inlet with axis of symmetry as the axis for rotation.
is it correct approach for the incoming flow through inlet.
Regards, Rohit
04-11-20, 1:27 a.m. rrohit2004

Hi Rohit,

Could you ZIP and share the case files with us? We could take a look at it. You can mail the ZIP file to contact-cfd@fossee.in.

Regards,
Ashley


04-11-20, 5:39 p.m. ashleymelvin

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Thanks for reply, i have mailed the case file to cfd@fossee.in. Regards, Rohit
04-11-20, 8:19 p.m. rrohit2004

Hi Rohit,

The email ID is contact-cfd@fossee.in

Regards,
Ashley


04-11-20, 11:12 p.m. ashleymelvin

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I am sorry, I have mailed it now to contact-cfd@fossee.in. If you could refer any similar case study it would be helpful. Thank you for reply Regards, Rohit
04-11-20, 11:50 p.m. rrohit2004


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How do we use and implement HRIC scheme for interface capturing and CSF model for surface tension in openfoam. Regards, Rohit
07-11-20, 2:24 a.m. rrohit2004

Hi Rohit,

I am assuming you want to know about how HIRC is implemented in interFoam. Since OpenFOAM implements both the VOF and Eulerian techniques to solve multiphase flows, the best way to understand each of those approaches is by look at the OpenFOAM exclusive hybrid solver, multiphaseEulerFoam. The paper below talks in detail about the interface capturing technique used in the solver. One of the terms in that eq, is the Calpha term, which for purely VOF technique (interFOAM etc.) tends to 1.

https://www.hindawi.com/journals/ijce/2013/128936/

Regards,
Ashley


08-11-20, 4:16 p.m. ashleymelvin

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Could you ZIP and share the case files with us?
17-11-20, 11:14 a.m. RoyKCarollJ456

Thanks for reply RoyKCarol, could you please send me the email address to send send the zip file. 


17-11-20, 2:53 p.m. rrohit2004

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