Error in geometry Fluent

[neder.thomas]

Hello, I'm a beginner in CFD and I want to do an axisymmetric simulation of a diffuser. I have 2 sketches, one is my control area where the fluid passes, in this case water, and the second sketch is a line that represents my diffuser. I generate the surface from my first sketch and a line from my second sketch. When I try to subtract one from the other, Ansys doesn't accept it, I believe because I'm trying to subtract a line from an area. Does anyone know how I can adjust this geometry to do this axisymmetric simulation of my diffuser?
P.S.: After I did this, I tried to open the mesh and it gave an error in the geometry that indicated that the diffuser line could not be there.

[neder.thomas]

I want to replicate this example

[NickFL]

Take a look here: https://innovationspace.ansys.com/forum/forums/topic/line-heat-source-in-a-2d-fluent-model/

You do not want to apply any heat transfer there, simply treat it as a wall.

[mr.davidbenjamin99]

You're right — Ansys won’t let you subtract a line from a surface because they're different geometry types. For an axisymmetric simulation, you just need the 2D flow region (your control area). The diffuser line is likely just a reference and shouldn’t be part of the final geometry — try deleting or hiding it before meshing.

I ran into a similar error when learning CFD while juggling some projects for getsmod.com. Cleaning up extra sketches made a big difference. Hope this helps!

[mr.johnmichael44]

Hey! You're right—ANSYS won't let you subtract a line from a surface because they're different geometry types. For axisymmetric CFD simulations, you typically just need the 2D surface (your fluid region). You can skip creating the diffuser line or just use it for reference. If you need a visual guide or tutorials, I often check resources like https://instaproapk.com.co/ when learning new tools. Keep going—you’re close!