Learning Forum

[Mahmoud Awaga]

the simulation started but the error occured update failed, the error is “Error: Consider adjusting the timestep control tolerances according to the cause of the timestep being too small”

how can i solve this problem?

[jcooper]

Hi Mahmoud:

 

The error "Recycling requested by spray/gas momentum coupling" in Ansys Forte typically indicates that the area near the wall film has become overly saturated with liquid fuel. This could be due to a high liquid fuel mass flow rate or spray parameters that do not allow for quick enough evaporation of the droplets. Adjusting spray parameters without experimental data can be challenging, and require a lot of trial and error, especially if the spray parameters are only partially known.  As a result, the error might be difficult to avoid without modifying the modeling approach. 

Since spray modeling is computationally intensive and Forte simulations are already time-consuming, an alternative was introduced in Forte V 19.2. This alternative is the fuel vapor mass flow boundary condition, which can serve as a stable replacement for spray injection, especially in cases where spray data is lacking or not the primary focus of the analysis. Utilizing this new boundary condition should help resolve the error and prevent the solution from recycling at a very small timestep.

 

Best Regards,

Judy