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Time step independence in Transient simulation with RPI Wall boiling |
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October 25, 2023, 08:35 |
Time step independence in Transient simulation with RPI Wall boiling
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#1 |
New Member
marcus aurelius
Join Date: Sep 2023
Posts: 18
Rep Power: 3 |
I am trying to simulate subcooled flow boiling in horizontal channel with Non-equilibrium RPI wall boiling model. It is transient simulation with Implicit scheme. Steady state simulation are not giving the true results so that scenario is already discarded. I have already performed grid independency and now trying to do time step converging/independence for transient simulation. Started with time step of 5E-02 and reduced upto 1E-05. But, the results keep changing every time. The results have shown to match when time step is around 5E-03. With smaller time step, The results keep changing significantly.
y+ is around 30. I am using ANSYS Fluent So, please help me how time step independence can be achieved? The models and schemes are listed in picture attached. |
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January 21, 2024, 11:39 |
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#2 |
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Pierre LECHEVALIER
Join Date: Mar 2023
Posts: 31
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Dear MarcusAurelius,
Do you have some figures to introduce ? Is it changing a lot when decreasing your time step ? Best regards, Pierre |
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January 22, 2024, 07:22 |
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#3 |
New Member
marcus aurelius
Join Date: Sep 2023
Posts: 18
Rep Power: 3 |
I have found out the reason for that. Selecting interfacial area model "ia-symmetric" instead of "ia-particle" solved the problem of Time step convergence.
But, the results are now way different than expected. The wall temperature is increasing by 2-3 times than actual. |
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Tags |
ansys, eulerian eulerian, fluent, multiphase, rpi wall boiling |
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