Screw Compressor
 

I am trying to conduct fluid analysis on a screw compressor.
The design is something like in this video.

https://www.youtube.com/watch?v=Pu5YX_qIPVo

The video employed a TwinMesh meshing software and CFX solver to efficiently run the analysis.

Apparently, I do not have the TwinMesh Grid software, so I am stuck with ANSYS Meshing.

How would one mesh something like this in ANSYS so it will work for Fluent?
I understand dynamic meshing is one way to go, but what would happen when there is no space between the mating parts?

Well for the moving parts you need the dynamic mesh which Fluent is capable of doing.
Check out this link for more information:
https://www.sharcnet.ca/Software/Flu...ug/node444.htm
If you want to mesh in ANSYS meshing there are several options, one is that you directly use the tetra elements. Other is that you divide the body that you want to several parts so you can sweep through it and do the hex meshing for fewer elements but you will spend more time on the geometry.

Well my question would be is, would dynamic meshing work when the two bodies are contacting together? the space is very minimum !

Give it a try with the Dynamic Remeshing in FLUENT.
I don't have experience with screw compressors but I would try first to see if Fluent can handle it or not.
When you have the connection simply it won't re-mesh that area.
In the end, I can't say if your results are going to better than the TwinMesh tool since that tool is developed for this exact purpose.