Non-Premixed Combustion PDF generation with 4th-order interpolation

[hmanatunga]

I have tried activating 4th order interpolation for PDF generation within the non-premixed model. Once the 4th order interpolation is enabled, I calculated the PDF. Once the PDF is generated, I get the following error:

Error at host: Internal error at line 3555 in file 'species/src/sg_pdf.c'.
User scalars in Pdf Table is not available

I do not have any user defined scalars enabled. The case file is of a problem that uses the non-adiabatic non-premixed combustion model in Fluent. P1 is used for radiative heat loss. The flamelet library was generated using Fluent's in-built flamelet generator.

I have followed the following steps to generate the pdf.

1. Load my case file
2. Enable 4th-order interpolation 

   /define models species non-premixed-combustion-expert 1 no 1 0.25 0.05 yes 1 1

3. Generate the PDF table

/define models species non-premixed-combustion yes yes no no yes no yes flamelet.fla , no 200 25 8 20 290 no no "./fixed-5.pdf" no

[Vijay Narayan]

Hi Mana,

Is the issue only with 4th order interpolation scheme ?.

If you generate the PDF table via GUI (default approach, no activation of 4th order interpolation), using either AGR or the specified entry for PDF table - do you see similar error ?

[hmanatunga]

Hi Vijay,

No errors when calculating PDF using GUI (w/o 4th order interpolation).

Mana

[Vijay Narayan]

Hi Mana,

Are you shifting the case from FGM partially premixed to Non premixed model ? Based on my discussion internally, this error could pop up when a shift is done from Partially premixed to Non premixed combustion model. The scalars mentioned are some internal variables which are used and not related to any user specified entry.

Could you set the case afresh in Non premixed model and let me know the outcome.

[hmanatunga]

Hi Vijay,

Thanks for that. Original case was set-up just with the non-premixed model. I just retried setting up a fresh case by reading the mesh and setting up the non-premixed straight away without setting up anyother fluent settings. Sadly, I am getting the same error. Might be helpful to note that I am using 2022.r1. The cluster that I am running my simulations at hasnt been upgraded to the latest version yet. 

Mana 

[Vijay Narayan]

HI Mana,

Thanks for sharing your observation.

I was able to reproduce the error when migrating from FGM Model to Non premixed model on a Tutorial example; and not while setting up the case afresh as Non premixed model.

It could be possible that the issue you are reporting is specific to your model; and as I cannot reproduce the error - I cannot give further assistance in the Forum channel.

If you could create a support ticket, I could investigate your model and get the necessary resolution.

 

Regards,

Vijay