## Preprocessing

#### Meshing a very low diameter and length tube rasio

• daveberutu
Subscriber

Hi Everyone, I am modelling a inconel 625 tube that use to transport fluid from the surface to the production well with depth 6200ft to see the stresses happen on the tube.

I have some trouble on meshing and modelling this very" long tube. The spesification is

outer diameter   : 0.375"

thickness          : 0.00625"

Length              : 6200 ft

Can you help me how to solve this situation?

Your help will be much appreciated.

• Rob
Ansys Employee

Given the dimensions wouldn't a shell model make more sense?  Given the cell count limits I'm not sure you'd be able to mesh it with the Academic/Student versions.

• peteroznewman
Subscriber

I agree with rwoolhou.  Go back the the Geometry editor, and create a Midsurface from the solid body.  Then just mesh that surface body.

• daveberutu
Subscriber

Thank u very much. I've made some progress on my model. But now, I meet new problem, I can't differentiate pressure load from external and internal tube because in my case there are fluids that flow from inner and outside tube. How can I solve this problem?

• daveberutu
Subscriber

How can I differentiate external pressure (that works on outer face tube) & internal pressure (that works on inner face tube) on this shell mode? What I can model is only the internal pressure (Caustic pressure) but the steam pressure that works at the outside pipe, I still can't figure it out how to model it.

• peteroznewman
Subscriber

For a shell model, you have to apply the difference in the inside and outside pressures to the face.

• daveberutu
Subscriber

How can I apply the difference pressure in shell mode? I can't click the outer face of the tube in shell mode. Just inner face can active

• peteroznewman
Subscriber

If the inside pressure is 300 Pa and the outside pressure is 200 Pa then the difference is 100 Pa and you want that directed outward from the tube.

Pick the tube surface and assign 100 Pa and look at the arrow. If it points outward, you are done, if it points inward, change the value to -100 Pa and it will point outward.

The surface normal might point inward or outward depending on which CAD system created the surface.