The story of this fan duct is very funny.
I wanted to redesign the original fan, because I thought a fan with a disc form could be better (in order to ventil on all directions at the same time, our fan ventil only on one side).
So I tried to draw a disc but without the small holes, With only one big peripheral hole.
disc nozzle.jpg
And I was looking for things to print on thingiverse and find this one :
http://www.thingiverse.com/thing:793310
So,i have downloaded it and modify it on sketchup, try different size...
essai nozzle.jpg
I have cut the original, add an extremity and design a connection with our fan to easily change it.