Blade design for a swirl generator (cyclonic separator)

Hello
I have been doing alot of research trying to find an answer but still i couldnt :S so i will show you the details and then will ask the question
here you go


so if you look at the fan and cyclone (which where the fan is going to be installed) i know there are some problem to fix and some of the problem i cant find an answer for it here are the problem
1- how can i decide the blade curve radius ?
2- the top cone on what basis should i design it ?
3- the bottom cone i know it should be 0 radius at the tip
4-the blade height on what basis should i design it as well
5- on what basis i am going to shape the blade (Airfoil)
and yes i am using solidworks 2012


Admin. ---> images should be attached directly to forum

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