Undesirable results obtained from hydrogen injection simulation, Forte

[sharanvenkatesh.211me344]

Hey guys! ,

My project requires me to compare a few results of a DI hydrogen engine under different operating conditions. I have been trying to replicate the stock simulation on hydrogen DI engine simulations on the Forte documentation. I have used the same mesh options used in the tutorial but have been achieving undesirable results, as shown below.

The minimum temperatures and the maximum flow velocity reach outrageous values. I have tried reducing the size of the maximum timestep in an attempt to mitigate this issue but haven't been successful. I also maxed out the mesh settings available for the student license.
However, I have observed that the chemistry set that the tutorial used is different from the one referenced in the document. Could that have misleading property values?
Any assistance in this regard would be appreciated!
Thanks in advance!

[Ren]

Are you referring to this tutorial:

Chapter 8: H2 Direct Injection Engine Simulation

Did you run the tutorial as is or did you make changes?

Which Forte release are you using?

 

 

[sharanvenkatesh.211me344]

Hey Ren!
Thank you for the quick response!
Yes, that is the tutorial being referred to.

Yes, I have made a few changes,

1. I have simplified the geometry, as the investigation only requires analysis of the early hydrogen injection during the compression stroke.
2. I have used the exact mesh sizes pertinent to the simplified geometry, except for the "injector" line type mesh. As the student version only allows for a maximum refinement of 1/8th of the global mesh size, I have changed the refinement of the "injector" mesh (originally 1/16th) to 1/8th and changed the "h2jet-always" mesh from 1/4th to 1/8th as compensation.
3. I have also changed the initial composition in the cylinder; the tutorial only contained nitrogen. I have changed the composition to air.

The Forte release being used is 2024 R2 student.
I have used the same parameters and conditions as the tutorial elsewhere.
I have also seen the message "recycling requested by scalar fluxing" in my previous attempts to run the simulation.
Could you please suggest possible fixes for this problem?
Do I try changing the maximum number of iterations for different terms?

 

Thanks in advance!