Rotational Domain and Radiation
 

Hi everybody,

I tried simulating a model which includes rotational and stationary domains. I have the heat transfer in my model , therefore I used the total energy model. When I wanted to simulate it with thermal radiation (DiscreteTransfer , participating Media model), I get the error below:

Pitch change is not supported with Discrete Transfer or the Monte Carlo Model.

Is there any point that I should consider? How can I simulate a model which includes both rotation and radiation?

regards,

The message told you already:

You need the same pitch on both sides of the interface. Can you replicate the domain on either side until the pitch is the same?

Hi, thanks for answer.
I have 360° Pitch on both sides. I simulated the model once with rotation and heat transfer but without radiation. This time I wanted to simulate it with radiation but made an error.

Hi,

is there anybody to guide me?

As I mentioned, the pitch changes are 360° for both sides. And I could also simulate the model without radiation. When I wanted to consider the radiation in my model, I face with the error. Is it something about my mesh quality?

+--------------------------------------------------------------------+
| ****** Warning ****** |
| |
| Topology simplification cannot be applied to domains with |
| 'Discrete Transfer' or 'Monte Carlo' radiation if boundary |
| coarsening is restricted to face sets (default behaviour). |
| In order to allow topology simplification for these domains, the |
| boundary coarsening must be restricted to boundary patches by |
| setting the expert parameter 'radiation agglomeration option=0'. |
+--------------------------------------------------------------------+

+--------------------------------------------------------------------+
| Radiation Coarsening Information |
+--------------------------------------------------------------------+

Domain Name : Rotor

Target coarsening rate = 64
Number of fine grid elements = 1799137
Number of radiation elements = 46598
Actual coarsening rate = 38

+--------------------------------------------------------------------+
| ERROR #001100279 has occurred in subroutine ErrAction. |
| Message: |
| Pitch change is not supported with the Discrete Transfer or Monte |
| Carlo model |
| |
| |
| |
| |
+--------------------------------------------------------------------+

+--------------------------------------------------------------------+
| An error has occurred in cfx5solve: |
| |
| The ANSYS CFX partitioner exited with return code 1. |
+--------------------------------------------------------------------+


This run of the ANSYS CFX Solver has finished.

The error message is pretty clear - you have a pitch change across an interface and this is not supported.

If you cannot find the error please post your output file and we will try to help you.

If you cannot find the error please post your output file and we will try to help you.[/QUOTE]

Dear Ghorrocks,

I am sending you the output file.

Please read the documentation, Solver Modelling Guide, section 5.3.3, about pitch change.

Have you tried Pitch Change Option = "Automatic", or maybe "None"? I suspect your specifying pitch angles are causing the problem, even though the pitch angles you define mean no pitch change is required.

Hi,

I changed the pitch change option to None, then it worked. I read the section, now I have another question. let imagine two interfaces in 2 Rotation and Stationary domains have different mesh elements, but overlap themselve compeltely don´t we need pitch changes?

The pitch change model is based on the pitch of the boundaries touching the interface. It is independent of the mesh used to solve it.

Be careful not to confuse mesh with the geometry either.