Experts in fans airflow, I need your advice

Elaphe · Jul 3, 2020

I have these Delta fans (12 cm, 4000 rpm max) in my cockpit. I am designing air strengtheners for them. Do you think I should add the hexagonal pattern or remove it? I've seen some designs and I've noticed most of them have this kind of grill, which is supposed to make the airflow go straight. Some use a different design, with something like a double cross. Wouldn't it block some air too? Wouldn't be enough with the duct to move the air to the center? I'm also worried about the design of my Delta fans. If you look at them you can see something like a fixed blade in front of the fan. What is that for? Would it interfere with design of my air strengthener? Thank you.

Fennario · Jul 4, 2020

+ The grill will focus the output of the fan into a cone with a smaller radius vs. without (less diffusion of the "wind" once it leaves the grid)
- It will make your fan work harder to produce the same volume of air (introducing resistance).
- The overall area impacted by the "wind" will be smaller (eg face vs. upper body)

+ Note the ducting w/ decreasing diameter (fan attached at the back to the larger end). The decreasing diameter forces the air to exit at a higher velocity.
- That said, the longer the duct, the lower the flow.

Flow rate varies inversely to length, so if you double the length of the pipe while keeping the diameter constant, you'll get roughly half as much through it per unit of time at constant pressure and temperature.

Elaphe · Jul 4, 2020

So, would you change anything in my design? I want as much air in my head as possible.

Fennario · Jul 4, 2020

Best way to maximize the flow on your head/face is to get the fans close. Distance & resistance are your enemy. Only use the grids if the spread is too wide.

If using ducting then you can run them in series (put 1 at the back and another ½ way down the duct). This will help mitigate the flow rate issue (may need to balance their relative cfm to avoid a low pressure area between the two fans).

wingert · Jul 4, 2020

another point to consider is, not to blow wind on hands and steering wheel because normally this parts are under the cockpit fairing.
Cheap and strong blower are from car ventilation , you can find it on your local scrap yard, high current power supply 12V from scraped server.

Elaphe · Jul 4, 2020

OK. Then I think I will remove the hexagonal grid.

Elaphe · Jul 4, 2020

Yes, that's why I will have my fans installed high enough. They are also as close to my face as my setup allows.

Fennario · Jul 4, 2020

Would think about mounting them on the exterior rails of your rig vs. behind/on the wheel deck. Looks like their current position would interfere with optimal monitor placement. Disregard my comment if VR.