Suggestions regarding meshing of a centrifugal impeller
 

Hi
I am trying to mesh a centrifugal pump's impeller in ICEM. I have started with a simplified geometry without the back and front fluid volumes. Being a novice to ICEM I am facing a lot of problems, for example I end up with holes in the surface mesh while meshing. I have tried creating blocks to make a structured mesh but as the vanes are curved backwards, I don't think its an easy task to block such geometry.
Would greatly appreciate if someone experienced can help me in this regard.

Thanks