Hi, I am doing a CFD analysis on a scroll compressor for my thesis project.

here is a good animation of what I am trying to simulate:

http://cryo.kaist.ac.kr/images/scroll_cw.gif

I am using mesh deformation, but the problem is that I have very large features (10mm) and very small features (0.02mm) deforming at the same rate, and as you can see from the animation, I have a wall that is static (blue scroll) and a wall (red scroll) that is in motion.

So what happen is that after deformation, the mesh will end up being so stretched that CFX returns a negative volume error. If it does not, I don't think a solution with this kind of stretching is accurate.

Can someone give me some advice on how to solve this kind of problem?

Thank you in advance.

Ji

Hi,

This form of motion will be very difficult to run in CFX. Your best bet is to do a good quality (preferably hexa) mesh and carefully adjust the mesh smoothing to avoid negative volume elements.

Glenn Horrocks

We did a lot of srew compressors and gear pumps, and the only chance in simulating so large displacements with changing gap sizes is to generate a lot of topological identical meshes for one revolution and let CFX read them in on runtime as is described in tutorial 20.