Hi @anurags and @sriramchari1
EDIT: Sorry, I couldn’t give an extensive explanatiopn on how I solved this issue as I was busy preparing for my exam. Here is the method I use when I work with MRF problems.
- Your CAD will play a very imp. role in the process of formation of a new cell zone. I usually make my CAD model in this format-
In your CAD models your blades are solid so, my first step was to use boolean cut operation to make that cavity in both the MRF cylinder and the main body. Thus there was no need to make a new assembly from scratch. Then I made a new mesh with MRF zone by using the “with cell zone” option in the surface refinement .
I made some modifications in the CAD model and now the MRF zone has been created properly and it is now able to assign B.C’s to the mesh surface. I am attaching the project link here- https://www.simscale.com/workbench/?pid=8500429970281485035&mi=spec%3Ad0d56b41-419e-4911-b8f5-5ef054630107%2Cservice%3ASIMULATION%2Cstrategy%3A2
You can either download the CAD model and assign desired mesh refinement in a new personal project or you can simply copy my project and work within it. Hope that helps 
Thanks
Ani