An annual competition in the Mechanical Engineering Junior Lab, all junior mechanical engineers design and build vertical axis wind turbines (VWATs) to see what team can generate the most electrical power as they push their turbine down a long hallway. With a max power output of over 25 watts, my team’s turbine blew out the competition, and set the competition record by 7 watts thanks to our telescoping design.
The project was multifaceted, we used wind tunnel testing, motor characterization, and dimensionless scaling to arrive at our final design. One of the largest design constraints is that all turbines must fit through the hallway door, which is approximately a quarter of the width of the hallway itself. In order to overcome this challenge, many groups use a folding wing design to fit through the door.
Through reynolds number analysis, my team opted for a Lenz Turbine: a hybrid design that combines the low speed drag forces of a Savonius turbine, and the high speed lift forces of a Darrius. However, the innovation crucial to our success was a telescoping strut mechanism that I designed. Made from aluminum tubing that connected to 3D-printed and lasercut hubs, the telescoping mechanism allowed the turbine diameter to expand from under 3 feet to over a 7ft operating diameter, without sacrificing blade size.
This larger radius allowed for higher torques to be produced, yielding our very successful results.