[engeagle]

Hello,

The flow in my simulation is laminar according to the calculations of Reynolds number. But fluent warns for reversed flows and it affects the convergency, especially for continuity equation. Also, hot air goes to upward direction in this simulation (flow direction is downwards). It never converges. When I used standard k-e turbulence model, I obtain better convergence. Can I use turbulence model for laminar flow? Does it effect the results?

Thank you.

[LuckyTran]

Don't use laminar model for turbulent flows and don't use turbulence models for laminar flows.

Is the reversed flow expected? If it is expected, make sure you specify the correct back-flow properties. If it is not expected, try to fix it. Undesirable reversed flow can easily be caused by an unrealistic boundary condition, i.e. a pressure outlet too close to your domain.

[engeagle]

Originally Posted by LuckyTran

Don't use laminar model for turbulent flows and don't use turbulence models for laminar flows.

Is the reversed flow expected? If it is expected, make sure you specify the correct back-flow properties. If it is not expected, try to fix it. Undesirable reversed flow can easily be caused by an unrealistic boundary condition, i.e. a pressure outlet too close to your domain.

Thank you for your answer. I activate gravity and radiation model. Air flows inside the furnace. And air is heated. Hot air rises with gravity, so I think there can be reversed flows. I tried different values for backflow temperature, but I couldn't solve it. I use simple scheme, Should I try another scheme for example coupled? Also, which pressure interpolation scheme should I use for better convergence?

Thank you.