[I-mech]

I'm trying to analyse fluid flow between rotor and pad of journal bearing with a "2 way FSI".
I have set fluid solid interaction to transfer pressure as a load in mechanical and it works like a charm but i'm looking for including thermal effect.
Fluid flow domain is so thick that thermal expansion of the pad becomes very important. Is it possible to transfer pressure and temperature simultaneusly?

i'll be very grateful if someone can help me.



in cfx i've realised a CHT to have pressure distribution in fluid domain, force on pad surface (interface fluid-solid), and temperature distribution on solid.

[stumpy]

Download these files from the ANSYS Customer Portal then look for workshop 4.

https://support.ansys.com/AnsysCusto...ANSYS+CFX+14.5

[I-mech]

Originally Posted by stumpy

Download these files from the ANSYS Customer Portal then look for workshop 4.

https://support.ansys.com/AnsysCusto...ANSYS+CFX+14.5

Thanks for your reply.
The problem is that i use Ansys with my University License and i haven't access to customer portal because of department internal burocracy problems.
I think it was the only possibility to download the workshop (correct me if i'm wrong), so i'll be glad if you can just give me a tip.

The following is a resume of my analysis:
- Steady State
- density and viscosity are function of temperature
- Cfx contain a fluid domain (lubricant) and a solid domain (pad) to do CHT
- rotor is not modeled because rotating wall BC is sufficient
- fluid thickness order is mm (less then 1 mm)
- 2 way FSI is necessary to include thermal expansion of the pad and deformation due to pressure at the interface.

For any detail, just ask. Thanks in advance.

[stumpy]

In Mechanical insert a Commands object below the Solid bodies that need structural and thermal degrees of freedom (Project > Model > Geometry > Solid > right-click > Insert > Commands). Select SOLID226 (hex) or SOLID227 (tet) elements by typing in:

et,matid,226,11

or

et,matid,227,11

Make sure the mesh you generate is consistent with the element type you have selected here.

Now set up the structural loads and constraints as usual, but do not use any Fixed Supports (they will set temperature to zero), use Displacements with zeros instead.

Set the Environment Temperature in Mechanical to the temperature which has zero thermal stress.

Insert a Commands object to set any thermal boundary conditions in Mechanical, using the D or SF commands. E.g.:
D,Named Selection,TEMP,80
or
SF,Named Selection,CONV,1000,10

In CFX-Pre set the FSI boundaries as usual, picking the ANSYS option under Mesh Motion and also picking the ANSYS option for the thermal boundary conditions.

Hope this helps!

[I-mech]

Thanks Stumpy for your reply.
You're so kind.
There's another doubt about it.
In this way Heat Transfer is manage by CFx or by Mechanical?
I mean... in a typical CHT analysis i have a fluid domain and a solid domain in CFx. If i want mesh motion due to pressure and thermal expansion, i need to build only the fluid domain in CFx and the solid domain in Mechanical, setting in Mechanical thermal BC for solid, am i right?
Or CFx calculate the CHT analysis and sends to Mechanical pressure and temperature of the solid domain?
When you say,

In CFX-Pre set the FSI boundaries as usual, picking the ANSYS option under Mesh Motion and also picking the ANSYS option for the thermal boundary conditions.

you make me think second setting is the correct one.

[stumpy]

CFX will only have the flow domain. Mechanical will have the solid regions and will calculate stress and temperature. You can't use the CHT approach in CFX because a fluid-solid interface cannot be an FSI region.