Active cooling is an absolute necessity for printing with PLA. It just doesn't cool fast enough to get good results otherwise. Axial fans do not provide the CFM and pressure to adequately do this job, in my humble, non-fluid-fluent opinion. Hell, I don't even know what laminar vs turbulent flow is. But a blower fan will provide more of what you want for this application than an 'axial' fan. Sometimes it seems too much, but my PLA parts have fine sharp edges so I thought I'd share what I've been sitting on for 2 years now.
Warning: The fit and finish is not perfect. I pride myself on releasing quality parts that actually print and work as intended, but this can be of use to many and I have sat on it for at least 2 years with minimal updates. Just print it as it seems, you might need to file to fit. Try to file the easily replaceable mount that screws into the fans, not the duct itself.
FET install is easy, but I hear newer printers come with this FET already. If you come across a tutorial and want me to edit this to put it here for reference, feel free to post. Since this is merely a blower fan version of the files it is remixed from, please see them for a proper reference text.
The non 'not4printing' version contains tiny supports that will support the directional fins I added to point the airflow down at the part, and not just cooling the nozzle without requiring printing 'with supports'. Print the 'Coolduct2.1.stl' without supports. I used 30% infill, 2 shells, .1 mm layer height. Break off the support structure. YMMV.
Inevitably, the blower fan has so much CFM that my nozzle and power supply can only maintain ~224 C equilibrium but this is ok, my prints are dank AF and y'all should be jelly. /s
Again, I apologize for releasing such shoddy works, I hope to clean it up later, but I'm sure it'll still be useful and I think this is what I would print today, if I were in the market for a free active cooling solution on Thingiverse.
Oh and if you mount a door/enclosure on your printer, it may not work when the printer reaches its maximum range of travel to the front. Still haven't gotten around to that one though so not a problem for me. Have fun ;)
'coolduct2.1.stl', 30%, 2 shells 0.1 mm in ABS
'Mountv3.stl' or 'Mount.stl' might need to scale 3% for ABS. Records indicate raft and supports were used
Break off the red supports