Cooling for printed part ..duct design idea's required

OK after printing parts and getting some ok results I have discovered that the quality of some printed layers is affected by the type of cooling duct you have.. more so on ABS than PLA .. and before I get all the comments on ABS does not require cooling, try printing the 3Dbenchy part and look at the state of the chimney

so looking through thingiverse I discover that there are not many original designs they are all based on other designs..

So I thought it might be a good idea to design the Duct in a couple of parts so that it was not printer specific..

1) the part that surrounds the hot end and focus the air to the correct place 360 deg coverage
2) Adaptor for each printer/type of fan.

...

It's not a bad idea but mostly people use 40mm fans as far as I know. To be compact and fit around the hot end while properly cooling the extruadate usually requres an "expert system", (a very specific solution) or there would be less fan designs on there!

My understanding is that the normal axial fans aren't well suited to blowing air into a duct... they're more suitable for sucking. I gather that radial fans are better for cooling the extruded filament.

It's popular in the 3D printing world to put small nozzles after axial fans but it's counterproductive. Better with an axial fan to keep most of the flow buw using a big nozzle. Centrifugal fans can deliver better loaded performance.