Effective Strategy for ensuring convergence using FLuent's Fan Model
If we switch on the fan model at the start so that it computes the Pressure Jump
from a fan curve, it is found that the solution diverges
after sometime and it predicts unreasonable mass flow-rates. Even limiting
the max and min velocity range does not work.
The solution is not to switch on the fan model at the start.
- Run the case for some iterations to get reasonable convergence.
- Determine the guess mass flow rate from the fan plane.
- Calculate the pressure rise for this guessed flow rate from the fan curve.
- Input this constant pressure rise in the Pressure-Jump option in fan model.
- Run the case with this constant pressure rise for some iterations till we get reasonable mass flow rates (within limits).
- Now switch on the the Polynomial option of Fan model to calculate the pressure rise from fan curve.
- Run it till we get the reasonable convergence.