## Fluids

#### Mesh multibody geometry

• ywang2524
Subscriber

I am trying to mesh a shell and tube geometry, there are many helically coiled tubes in one shell. Can I use different type of mesh on the three parts, i.e. the shell side flow, the solid wall and the tube side flow? And what should I do to the contact surfaces? I used to simulate the shell side and tube side separately, and use sweep method for the tube side and use tetrahedral method on the shell side (sweep method is not applicable for the shell side). Now I want to simulate all parts together and it takes forever to mesh. The geometry is 100 mm long, consisting of 48 helically coiled tubes with diameter as 1 mm and wall thickness as 0.1 mm.

Ansys Employee

You can mesh them separately and then use non conformal interface in Fluent.

Please go through help manual for more details

Regards,

Keyur

Guidelines on the Student Community

• Rob
Ansys Employee

Have a look at sequential meshing in Workbench too.  I'd also advise reading up on Fluent's thin wall heat transfer: do you really need to model the tube walls?

• ywang2524
Subscriber

Thanks for replying. How can I simplify the mesh problem if I do not really need to model the walls? The resistance is negligible, and I only want to see how the boundary of the two sides look like.

• Rob
Ansys Employee

You can merge the metal part with one or other fluid zone. Then label the surface as a wall so you can find it in the solver. Note, the thin wall has no physical presence so if it's "thick" compared to the diameter the area variation relative to the real case might be significant.

• ywang2524
Subscriber

Is "merge" an operation of the exact whole geometry or I only draw the other two parts while building the geometry?

• Rob
Ansys Employee

If you have the metal part you can merge that with one of the fluid zones. Or just split the fluid zone with the thin surface. The best option depends on the starting point.

• ywang2524
Subscriber

Ok thanks, I will try "Form New Part" in DesignModeler.

• Rob
Ansys Employee

That'll not change the geometry just the way the connecting faces are shared. Have a look at Boolean operations.

• ywang2524
Subscriber

I did some studies on shell conduction in fluent, is it the right thing to do after merging the wall with one fluid? But I found nothing on sequential meshing from Meshing user guide, can I have some more information? Thanks so much.

• Rob
Ansys Employee

Found it, https://ansyshelp.ansys.com/account/Secured?returnurl=/Views/Secured/corp/v222/en/wb_msh/msh_bbb_meshing.html  The tool has been mislabelled a few times, possibly including this one! Sorry.