Wind tunnel for testing 120mm fan

prusaprinters

<p>This design is a 3D printable wind tunnel for testing the airflow performance of 120mm fans. It was designed to be similar to the one seen in The Fan Showdown from the YouTube channel Major Hardware. This can be used to test your own designs for The Fan Showdown at home.</p><p>In addition to the printed parts you will need:</p><ul><li>A sheet of standard Bristol board, plate finish (smooth), 36 by 48 inches in size (90x120cm).</li><li>8x M3 and/or M4 bolts and nuts. 4x should be at least 18mm for mounting the fan plate to the diffuser. The other 4x should be at least 12mm for mounting through an open-frame fan or at least 40mm for mounting through a 25mm fan. Similar Imperial and US Customary sizes will work too.</li></ul><p>All parts should be printable without supports. PLA is recommended. I used a 0.6mm nozzle with 0.3mm layer height and 0.7mm line width, but a 0.4mm nozzle with standard settings should also work fine.</p><p>The flow straightener requires special slicer settings. The 3D model is solid. To make the vane pattern in it, set the number of top and bottom layers to zero and select a grid or triangular infill with a distance of about 10mm between lines. To ensure rigidity, aim for at least 1mm walls (3 perimeters at 0.44mm line width, 2 perimeters at 0.7mm line width).</p><p>To make the tubes, cut the Bristol board into two sections, with one being roughly 36x12 inches &nbsp;(300mm long) and the other 36x24 inches (610mm long). For each tube, cut the width so that it makes a 120mm diameter cylinder when rolled up. Leave some overlap - about 30mm worth. This should come out to roughly 410mm (16 inches). There should be enough material to make two sets in case you make a mistake with the first one.</p><p>Slide the fan diffuser stand over the narrow end of the fan diffuser. Insert the flow straightener into the flow straightener casing from the side with the tabs, aligning the tabs in the casing with the slots in the straightener. Insert all the way down until it seats and then turn so that the tabs are no longer in line with the slots. Slide the stand over the flow straightener casing.</p><p>Take the 12 inch / 300mm long Bristol board and roll it up into a cylinder 120mm in diameter with the smoothest side inwards. Insert one end into the recess in the narrow end of the diffuser. Insert the other end in the recess of the flow straightener with the tabs. You can now tape the seam of the tube. Optionally, tape around the joints between the tube and the plastic parts at both ends.</p><p>Now take the 24 inch / 610mm long Bristol board and also roll it into a cylinder 120mm in diameter, smoothest side inwards. Insert one end into the recess of the flow straightener. Slide the tunnel stand around the other end to support it. You can now tape the seam of the tube. Optionally, tape around the joint between the tube and the flow straightener.</p><p>Using 4x bolts, mount the fan to the fan plate such that the air flows into the plate. Using the other 4x bolts, mount the fan plate to the diffuser with the fan on the opposite side of the plate from the diffuser.</p><p>To use, apply power to the fan and measure the airspeed directly at the open end of the tunnel using an anemometer. Measure in multiple locations throughout the area of the opening to ensure consistent air speeds. If air speeds are not consistent, you may require a longer tube.</p><p>Good luck and I hope to see you on the Fan Showdown! Please consider sharing your designs with others so that we can all learn and improve our designs.</p>