[mactech001]

Hi all,

I encountered a problem while importing CFX-Convection into a Transient Thermal analysis. The error message below appeared:

An error occurred while transferring loads/supports/contacts: CFX Presure load was not created. Please check the correctness of the CFX results transfer process.

1) How should i go about solving this error please? I looked into the Solution information, and all it shows is:
-- ERROR -- Syntax error: readsession parameters should have the format: param=value

2) Why does it require me to include CFX Pressure when i'm only performing thermal analysis please?

thank you for your kind attention, and i look forward to hear of any comments/suggestions.

Thanks!

Regards,
mactech001

[ghorrocks]

You can do transient thermal analysis in CFX. No need to go to ANSYS, so no need for FSI.

[mactech001]

Hi Glenn,
thank you for your response.

sorry... i should've made myself clearer.....

my reason to use CFX - Workbench for the transient thermal analysis is because i'm taking the following approach to perform a fluid-thermal analysis on an electrical machine inside an aluminium housing with water-cooling channels within the housing. The model consists of: 1) housing with water-cooling channels; 2) the fluid model that fills the water cooling channel volume in the housing; 3) machine lamination; 4) machine insulations; 5) machine coils

the procedure i plan to take is:
1) use CFX-meshing to mesh only the housing and fluid model
2) assign maximum heat loss of the machine via heat flux to the inner face of the housing
3) define inlet fluid temperature and flowrate of fluid

4) after CFX calculation, import CFX-Convection onto the channel faces in WB Transient Thermal
5) define coil and lamination Internal Heat Generation
6) use Automatic Meshing for the remaining lamination, insulation and coil models
7) suppress fluid part in WB
8) solve for thermal analysis of model with housing,lamination,insulation and coil

Are the steps described above correct to perform this kind of fluid-thermal analysis please?

I didn't include the coil and lamination model in the CFX-meshing because CFX-meshing gave me lots of meshing problems/errors. and further, how do i assign the heat loss of the coil and lamination as watts per unit volume in CFX?

thank you for your kind attention, and i look forward to hear of any comments/suggestions.

Regards,
mactech001

[ghorrocks]

Looks like you could still do this entirely in CFX. What makes you think you need to use ANSYS?

[mactech001]

it made me think i should do it in ANSYS, because i have problems meshing the coils, laminations, insulations in CFX-meshing. meshing the coils, laminations and insulation seem to be easy in ANSYS using Sweep meshing or automatic meshing.

[ghorrocks]

You can import meshes from ANSYS to CFX. CFX can take meshes from many formats, you are not forced to use CFX-Mesh. I have not used CFX-Mesh for years.

[mactech001]

Hi Glenn, thanks for your reply. it does make my problem much more easier.

however, may i ask, how important is applying inflation in the fluid model while performing the CFD simulation please? if the CFX-mesh the only mesher to produce inflation in the fluid model?

furthermore, how could i apply an Internal Heat Generation (watts per unit volume) in CFX please? Or do i have to convert the Internal Heat Generation in ANSYS into Heat Flux (watts per unit area) in CFX?

regards,
mactech001

[ghorrocks]

how important is applying inflation in the fluid model while performing the CFD simulation please?

If accurate modelling of a thin boundary layer is important then it is important. That depends on the simulation you are doing - I suspect from your description you will have thin boundary layers so yes, it will be important.

i[s] the CFX-mesh the only mesher to produce inflation in the fluid model

No, many meshers can do inflation. ICEM and Gambit are two other options. You can also do inflation in the WB mesher in V12.

furthermore, how could i apply an Internal Heat Generation (watts per unit volume) in CFX please?

See the conjugate heat transfer tutorial problem. I see in V12 they have changed this tutorial to use the new electric beta option, so you get the heat generation directly from the resistivity of the material. This may be useful for your approach also.

But to answer your question, a heat source can be added by defining a subdomain volume and specifying an energy source on it.

[mactech001]

Hi Glenn,

found out CFX v11, i can define a subdomain and apply heat in W/m^3.

By the way, how can i define a tabulated material property in CFX-Pre please? I have a table of temperature versus thermal conductivity.

[alinik]

Dear all

I am recieving the same error message

"An error occurred while transferring loads"

I am simulating a one way FSI problem inside a pipe.
after finishing the solution of flow field, it seems that I fail to import and impose pressure loads calculated in "flow problem" to "static structural" problem as a boundary condition

Does any of you have a solution?

hope to hear from you soon

Regards

[mactech001]

Hi alinik,

the key is to ensure that the meshing you used for CFX calculation is the same as in the Workbench environment.

say u've meshed the solid and fluid models in WB. then, u import it into CFX and do the CFX calculation. after that, u import CFX Pressure onto the surface. During the process, from meshing to importing CFX Pressure/CFX Convection, the solid and fluid mesh or geometry CANNOT be SUPPRESSED. otherwise, it'll change the mesh again.

try and check on ur procedure. could be the case that u suppressed either one of the solid or fluid before u've imported the CFX results into WB.