[TCosta]

Converge version 2.2.0 solver tells that only allows translating or rotating moving solids for a CHT simulation. Does version 2.3.0 allows for arbitrary solid motion for CHT?

On version 2.3.0 the simulation runs good with an arbitrary motion for the solid, however the super-cycle does not start which ever the timing I set.

inputs.in
1 crank_flag
360.0 start_time
1800.0 end_time

supercycle.in
360.0 supercycle_start_time
60.0 supercycle_stage_interval
12 supercycle_stage_num

From the above timings the fluid solver should stop at 420 deg for the super-cycle to run. However, on my case nothing happens, and the fluid solver continues as nothing happened. Is this the right way to run CHT with a moving solid, or there is something else that I'm missing?

[SauravMitra]

Hi Tioga,

It should be possible to run CHT with arbitrary motion. Just want to know, how you are confirming that super-cycle is not on ? Do you have screen_print_level=2 in inputs.in (Simulation Parameters-Run Parameters -Misc-Screen print level -Verbose in Studio) ? Are you not seeing supercycle_sie_iteration in logfile at 420 degrees ?

Let us know.
Thanks

[TCosta]

Thanks for the help Saurav.

I don't see the supercycle_sie_iteration. I can only see the Ustar, pstar, density, and sie iterations on the log file at 420 degrees. The same for the cyles before and after.

[SauravMitra]

Hi Tiago,

Would you be able to send me the setup files you are using ? Let me see what is going on.

Thanks

[TCosta]

Originally Posted by SauravMitra

Hi Tiago,

Would you be able to send me the setup files you are using ? Let me see what is going on.

Thanks

Saurav, I sent you a PM.

[SauravMitra]

Hi Tiago,

There has been a mistake on my side. Somehow I misinterpreted the supercycle_stage_num as 1 instead of 12 in your case.
The way Supercycling will work in your case is as follows:

a) CONVERGE will store heat transfer coefficients and temperature at the INTERFACE boundary sequentially in 12 stages at 60 degree intervals.

b) After 360+720 (12*60) =1080 CAD, CONVERGE will time-average the heat transfer coefficients and temperatures of all the stages, which is also when the fluid solver will get paused.

c) CONVERGE will then make use of the time-averaged heat transfer coefficient and temperature for the solid steady-state calculations. This will be reflected by supercycle_sie_iterations in logfile.

Go to our downloads website and follow the path :
CONVERGE_2.3/Training_Materials/Internal_Combustion_Engine_Modeling_in_CONVERGE/Lecture_Slides/Session12-CHT.pdf

At slide number 33, there is a diagram explaining the workflow of Supercycling for engine simulations.

To sum it up, you will expect supercycling at 1080 degrees and not after 420 degrees.
I must apologize for the confusion, this might have created.

Best,