3d printed fan duct design.

[Takumidesh]

So my ender 3 power supply has a loud as hell fan on it, and I am trying to figure out a way to duct the air out of it to cool it without sacrificing too much performance of the fan.

Additionally the printer is oriented currently so the fan blows right on the window. I don't know too much about fluid dynamics, other than avoiding sharp corners, venturi effects, etc.

I see a lot of STLs for fan shrouds but the common thing i see is that they all are short stacks that eject the air almost 90 degrees out. Great for space but I can't see the airflow not being severely effected by the shape.

 

Im working on a model, will add it to the thread when I get home.

 

Anyone with good fluid/aerodynamics experience have any tips and/or resources?

[dcgreen2k]

I've been using one of the short 90 degree fan shrouds you mentioned on my Ender 3 for about 4 years now. In my experience, the power supply doesn't get hot enough to require maximum airflow and the fan doesn't move that much air anyway, so the fan shroud doesn't noticeably affect thermals. All of my fluid dynamics experience comes from designing engine intake manifolds, but if you're set on making a custom shroud I would recommend one with a smooth 90 degree bend (such that the opening faces the back of the printer) and baffles on the inside, parallel to the direction of the airflow. This should dampen the noise a bit without creating too much of a restriction. If you're willing to experiment, you could also try making a shroud that doesn't have a bend but keeps the baffles.

[Takumidesh]

13 minutes ago, dcgreen2k said:

I've been using one of the short 90 degree fan shrouds you mentioned on my Ender 3 for about 4 years now. In my experience, the power supply doesn't get hot enough to require maximum airflow and the fan doesn't move that much air anyway, so the fan shroud doesn't noticeably affect thermals. All of my fluid dynamics experience comes from designing engine intake manifolds, but if you're set on making a custom shroud I would recommend one with a smooth 90 degree bend (such that the opening faces the back of the printer) and baffles on the inside, parallel to the direction of the airflow. This should dampen the noise a bit without creating too much of a restriction. If you're willing to experiment, you could also try making a shroud that doesn't have a bend but keeps the baffles.

I may just try printing one of that style tonight then and see how it goes.
I was thinking of maybe doing a short 'reverse' velocity stack style maybe 3-4 inches, if that makes sense. ideally to quiet it down I was thinking to try to induce laminar flow, but my knowledge air is critically lacking lol.

 

[dcgreen2k]

The velocity stack idea sounds interesting, although I'm not quite sure how you could induce laminar flow or whether that would help at all. I imagine most of the noise comes from the fan itself rather than the turbulent air coming off it.

 

Here's the fan shroud I use on my printer: https://www.thingiverse.com/thing:3703510

You can see what I mean by baffles on the inside; they're meant to absorb sound while letting air pass by easily.