Nielsen-Kellerman's ongoing efforts to improve measurement accuracy and certification for our products led the mechatronics team to begin the specifications and design of a subsonic wind tunnel. As the lead for this project, I began spec'-ing our velocity, test-section size, and testing process requirements. ​

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I'm not familiar with wind tunnel design, so I began reading available material online and a textbook in our company library: Low-Speed Wind Tunnel Testing. This material was great help and allowed me to begin spec'-ing. Our tunnel will be used in production and continuously run throughout our day shift. It will test anywhere from 50 or more units. Recirculating air instead of dumping it into our ambient warehouse environment would be best. Therefore, an open-loop setup should be more energy efficient than an open-loop setup.

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The test section's cross-section will be roughly .4 m by .4 m. The max speed desired in the test section is 10 m/s. This is the average speed our products will see in real-life. With these, I calculated the required minimum CFM from our driving fan- 3,390 CFM. 

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From here, I followed general guidelines from the textbook and online material to design the various sections of the tunnel. I'm aiming for a sufficient contraction ratio for laminar airflow within the test section. My current design has a ratio of 6:1. 

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This project is still under development and a BOM is in the process of being completed. I'm currently working through CFD analysis in ANSYS to reiterate my design (if needed). Our main constraints at the moment are warehouse space (which can be fixed with space optimization) and budgetary. I hope to reduce the overall footprint of the wind tunnel through CFD analysis. This would help our budget problem. The current footprint is 4 ft x 7 ft x 18 ft. ​I will likely construct the majority of the tunnel from plywood and sheet metal for the transition ducts near the fan. The support material is currently aluminum extrusion. The test section will be further designed once a wind measurement device is selected. 

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