Scale-Model Testing of Tethered Undersea Kites for Power Generation

Fredette, Ryan

Etd

Scale-Model Testing of Tethered Undersea Kites for Power Generation

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This research focuses on studying the feasibility of tethered undersea kite (TUSK) systems for power generation. Underwater tethered kite systems consist of a rigid wing that moves in a circular or figure-8 path below the surface. The tether can connect to a platform mounted either on the surface or anchored to the seafloor. On the kite is a turbine that extracts energy from the kite’s forward motion, which has the potential to be several times the current velocity. This speed multiplication combined with the density increase of water as opposed to air is one of the main benefits of this class of systems over wind turbines. A scale-model TUSK kite was designed. Testing was conducted in a water flume at Alden Research Labs (ARL). Model scale factors were determined from a real world prototype TUSK system currently in commercial development. The scale-model kite was primarily constructed out of ABS plastic using 3D printing rapid prototyping methods. Other components of the system were either repurposed from prior projects or constructed with traditional methods. Testing was conducted at current speeds of 0.15 m/s, 0.31 m/s, and 0.46 m/s; kite pitch angles of 80, 85, and 90; and over circular and figure 8 trajectory shapes. Data collected included the azimuth and declination angles of the rigid tether as well as the power output of the generator on board the kite. Filtering techniques were employed on the data to generate graphs of kite position, velocity, and output for analysis. Relationships between current velocity, kite velocity, kite pitch angle, and power output have been measured. Inaccuracies in the model and areas for improvement in future work have been identified.

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