System Design and Operation

Applied Riverine Turbine Design

Led by William Baxley, MS, PE
Affiliated Home Campus: Harbor Branch
Affiliated Department: Southeast National Marine Renewable Energy Center
REU Scholars: Alexis Clark and Geoff Cole
REU Scholar Home Institution: Florida Institute of Technology

PROJECT

Harvesting energy from flowing rivers could potentially provide electricity to remote regions of the world along river systems that have historically not had access. River current turbines, due to close proximity to shore, do not face some of the major hurdles that ocean current turbines face such as cost of infrastructure and the transportation of electrons back to land. However, one major hurdle stands in the way of the successful deployment and operation of riverine turbine arrays, debris fields. The scope of this project is to develop a patented breakaway attachment system for hydrofoil blades on a river current turbine to overcome the issue of debris impact on turbines in river environments. In order to design the breakaway blade system, the forces at the blades’ attachment points must be accurately calculated. A test apparatus was designed to facilitate physical testing of the full-size blade at the design flow velocity.

The test apparatus consists of the strain test section and a hydrofoil blade. A fixture mount was designed to suspend the test apparatus from the front of a barge during physical testing. The strain test section was designed using Matlab to study the relationship between strain and wall thickness for various sizes of pipe. This data was used to determine the physical dimensions of the test section. CAD models were generated and underwent a finite element analysis simulation to ensure material failures were avoided and the design strain was achieved in the test section. Once built, the test section was outfitted with strain gauges that electrically measure the strain produced as the blade rotates from 0 to 90 degrees. Forces acting on the system can then be calculated from collected strain gauge data. The hydrofoil blade was 3D printed and reinforced with epoxy to make it rigid enough to withstand physical testing. To rotate the blade and collect data at different angles, a linear actuator was fitted with linkages that allow translation in three dimensions. The blade was then fixed to the strain test section in preparation for physical testing. The physical test will be conducted by fixing the mounted apparatus onto the test barge and lowering the blade into the water as the barge travels at the design speed.

Click here to watch the student presentation.