Axial Fan Statorinator

thingiverse

This is a significant upgrade to my previous creation found here: https://www.thingiverse.com/thing:3620191. I've curved the vanes into a genuine fan stator, which effectively smoothes out swirling air flow by straightening it more efficiently. Axial fans excel at moving large volumes of air at low pressure. However, ducted axial fans face significant challenges. The strong negative pressure vortex created behind the motor hub is one major issue. Inserting a cone to fill this volume significantly improves airflow within the duct. Another problem with axial fans is their efficiency drops as back-pressure increases more rapidly than radial fans. Air starts spinning around with fan blades when it's not being pushed along the axis of the fan. To visualize this property, imagine blocking off both sides of the fan by laying flat objects like cardstock and turning it on. In this case, you have zero airflow, and air trapped between each blade simply spins around inside the fan housing with the blades. Adding fins to the duct behind fans reduces the swirling of air within the duct. I tested the first stator in the pictures and saw a remarkable improvement in airflow. I then thought about increasing the size of the fins but haven't done so yet. My anecdotal evidence is, of course, meaningless. Lord Kelvin's quote rings true: "I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meager and unsatisfactory kind." After searching extensively, I couldn't find an easy way to measure airflow. If someone can do that and provide comparative numbers, I'd be grateful. I tore a small piece of paper and held it over and under the fan with and without this "inator" and noticed a difference. I would love to assign actual cfm numbers to it. I've included four versions for each hub size: two different fans on my printer - a decent Sunon fan with an 18mm hub, and some budget fans with 24mm hubs. Each version has one with small fins and one with large fins. I've tested the 24mm, short fin version." I'm still experimenting to measure airflow through the system effectively. I'm considering making an venturi and attaching a simple manometer. As cfm increases, so should the pressure drop through the manometer. This alone would be a useful data point to compare airflow improvements, but maybe there's a way to convert that value to a cfm. As I forgot to mention in my previous thing, I have two brands of fans - one with a 24mm hub and the other with an 18mm hub. If you have a fan with a different diameter hub, post a comment, and I'll try my best to get another statorinator uploaded that will work with your fan. Lastly, my fans spin counter-clockwise as viewed from the top (inlet) side. If your fans spin in the opposite direction, mirror the parts in your slicer.