VAWT : Vertical Axis Wind Turbine
Junior Design Lab I at UPenn
Fall 2014
Student teams were to design and build vertical axis wind turbines to generate electricity when pushed on a cart down a short hallway. The goal was to produce the most electrical power. My partner and I decided to pursue a Savonius style turbine over the Darrieus style because it is self-starting and easier to construct multiple prototypes.
FINAL VAWT
CONSTRUCTION DETAILS
The project can be broken up into two parts: the “turbine problem” and the “generator problem.” For the “turbine problem,” I parametrically modeled Savonius turbines in SolidWorks and made a range of small turbines for testing in a 12” wind tunnel. I then used dimensional analysis to investigate the effects of varying turbine height, turbine diameter, and blade depth on the efficiency of a single stage Savonius rotor before deciding on a final design.
MODEL SAVONIUS TURBINES
POWER COEFFICIENT VS RELATIVE SPEED
To solve the “generator problem,” I characterized the DC motor we were using as a generator and wrote a MATLAB script that takes in the estimated power and torque of the full-scale turbine and outputs the optimal gear ratio between the turbine shaft and the generator shaft to maximize electrical power generation. I constructed the turbine from cheap, lightweight materials (balsa, cardboard, architectural foam core, and plastic sheeting), and the gearbox from MDF.
MATLAB GENERATOR MODEL OUTPUT
Our turbine placed seventh against twenty-six other teams. While our gearbox was optimized for a power output approximately twice that of the actual power measured on test day, we generated the most power of any team using a single stage Savonius turbine and had one of the largest (5’ x 6’) and lightest designs.
POWER OUTPUT ON TEST DAY
TEAM ON TEST DAY