Learning Forum

[ywang2524]

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.

[Keyur Kanade]

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

Please go through help manual for more details 

Regards,

Keyur

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[Rob]

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]

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]

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]

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

[Rob]

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]

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

[Rob]

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

[ywang2524]

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]

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.