| Popis: |
Tidal energy harvested from flowing ocean waters is a promising sector of renewable energy in many coastal areas of the world. Challenges of cost mean that more efficient turbines are required to make tidal energy comparable with other energy sources. Downeast Turbines is developing a shrouded tidal turbine with patented rotor and channel system that concentrates ocean currents flowing through. Flow goes in with energy and comes out “spent,” its energy removed. Discharging spent flow back into the tidal stream is not an easy matter to perform, and two problems are commonly encountered: impaired efficiency of the turbine and impaired efficiency of a tidal turbine farm. Downeast Turbines' Lateral Effluent Discharge Apparatus, with patent application published and patent recently issued, addresses these two problems. It provides a means to discharge turbine effluent laterally into an acceleration zone of the stream that passes by, instead of directly to the wake downstream.In 2017, a series of two-dimensional computer simulations (2-D CFD) was performed at the University of Rochester to assess how the novel apparatus works. Nine configuration variations were modeled and tested in varying conditions of ambient flow speed and turbine load. Over 250 simulations were performed, and sample results are provided in figures and a table to show how the novel apparatus performed. Color maps of pressure, velocity and streamline vectors, and CP performance calculations, all suggest the novel apparatus works. Benefits of the apparatus might improve performance for any shrouded tidal turbine, not just Downeast Turbines' own. |
