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Convergence Problem using RPI boiling model in a horizontal 3D tube

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Old   November 9, 2021, 11:52
Default Convergence Problem using RPI boiling model in a horizontal 3D tube
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Babak
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Hi everyone.

I'm modeling a boiling steady state flow in a 12 m horizontal circular tube with ID=50 mm and OD=70 mm based on a papers geometry with the mass flow of 0.3 kg/s and under a Uniform heat flux and since the water enters the tube as a saturated liquid I'm using the non-eq RPI boiling model for my simulation to consider vapor convection and I have tried both K omega sst and K epsilon realizable as my turbulence model.

So far the results of the simulation for both turbulence models are near the results of the paper but the problem is my residuals are way to big to consider the simulation converged. (I have monitored few variables and they are stable)

here is a picture of my residuals for K omega sst and you can see that the residuals are not converging and fluctuating.

same thing happened when I used K-e realizable model; continuity and e were fluctuating around 1e-3 and the rest were around 1e-4.
so my question is that how can I obtain full convergence?
Thank You in advance and sorry for my bad grammar.


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boiling flow, convergence, convergence failure, eulerian multiphase flow, rpi model

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