[Tulo]

Hi All,

I do have a .def file from a simulation that run successfully on CFX-5.7 (2005) and the results are there.

I am reading this file into CFX-20.2 and the run is returning the attached error after 100 iterations.

How do I solve this error?

[JuPa]

Read the warnings. It's telling you your outlet has stuff coming into it. Either move the outlet further away or set it to an opening.

It even suggests a corrective action - "If this situation persists, consider switching to an Opening type boundary condition instead."

Also you have particle tracking issues. Disable particle tracking and run the simulation and see if that isolates the problem.


Edit: if you're just re-running the 2005 results into a 2020 version then there may be issues Discretisation has changed in the last 15 years. By way of example in multiphase flow the so-called "minimum volume fraction" which is set to 1e-6 has changed values so many times over so many versions that if you ran a simulation with it on using old CFX and ran it on new CFX it would error out.

[Gert-Jan]

We at the forum are experienced users that run simulations on a daily basis with the latest versions. We do not wait 15 years before rerunning an old case. Therefore, don't expect us to have an answer ready straight away. This is a very uncommon situation for us.

Nevertheless, you have a very complicated simulation with particles in a coal combustion calculation with radiation. It would be strange if things would not have changed in 15 years. And what has changed? Only ANSYS knows. Therefore, I would double check all settings before hand in CFX-Pre.

BTW, did you generate a new definition file using CFX-Pre? Or did you start from the original definition file

[Tulo]

Originally Posted by JuPa

Read the warnings. It's telling you your outlet has stuff coming into it. Either move the outlet further away or set it to an opening.

It even suggests a corrective action - "If this situation persists, consider switching to an Opening type boundary condition instead."

Also you have particle tracking issues. Disable particle tracking and run the simulation and see if that isolates the problem.


Edit: if you're just re-running the 2005 results into a 2020 version then there may be issues Discretisation has changed in the last 15 years. By way of example in multiphase flow the so-called "minimum volume fraction" which is set to 1e-6 has changed values so many times over so many versions that if you ran a simulation with it on using old CFX and ran it on new CFX it would error out.

Many thanks JuPa, I have fixed the boundary error issue. I guess I have to relook into the set-up, understand and perhaps fix the changed portions.

[Tulo]

Originally Posted by Gert-Jan

We at the forum are experienced users that run simulations on a daily basis with the latest versions. We do not wait 15 years before rerunning an old case. Therefore, don't expect us to have an answer ready straight away. This is a very uncommon situation for us.

Nevertheless, you have a very complicated simulation with particles in a coal combustion calculation with radiation. It would be strange if things would not have changed in 15 years. And what has changed? Only ANSYS knows. Therefore, I would double check all settings before hand in CFX-Pre.

BTW, did you generate a new definition file using CFX-Pre? Or did you start from the original definition file

Thanks Gert-Jan, I guess I have to relook into the changed portions in the couple of years I have been away from CFD, I had been with DEM in the couple of years so, yeah, I have missed a lot.

I did started with an old definition, recreated it with unsuccessful validation of problem physics and the error is as attached.

[Gert-Jan]

That is not an error. Just a warning that you use expert parameters. In principle nothing to worry about. I would go for it.