Design blade for swirl generator (cyclonic separator)

q8rix

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
https://dl.dropbox.com/u/86410588/fan1.zip

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