A forty percent improvement onturbine blade power production is huge. Design decisions have turned on far less than that. Obviously this design protocol will beadopted for turbines generally and plausibly the differential is sufficient tojustify refitting present systems were practical.
More likely though, with moneynow going into tidal turbines, this system may make that industry work as thatmost approaches the operating conditions experienced by the basking shark
Without question, taking powerfrom water flow needs to be carefully managed through design. The actual speeds are quite slow though the effectivereaction mass is large and compression is not a usable factor. Thus any disturbance in the flow design bleedsof energy.
Filter feeding basking shark inspires more efficient hydroelectricturbine
By DarrenQuick
00:03 February 7, 2011
Studying the bumpy protrusions on the fins of humpback whales hasalready led to more efficient wind and tidal power turbines and now nature is once again thesource of inspiration for a new and more efficient hydroelectric turbine. Thelatest source of biomimicry is the basking shark, which industrial designstudent Anthony Reale has borrowed from to create "strait power," awater-powered turbine generator that tests have shown is 40 percent moreefficient than current designs.
Despite being the second largest shark in the ocean, the basking sharkis generally considered harmless to humans as it is a filter feeder. It swimswith its mouth open to sift zooplankton, small fish and invertebrates from thewater before the water is expelled through extended gill slits that nearlyencircle its whole head. Although this flow of water assists in the shark’sswimming, Reale recognized that the shape of the shark’s body also played animportant role.
With the basking shark’s jaw able to stretch up to 1.2 meter (3.9 ft)in width, a pressure differential is created as the shark swims. As with thewings of an airplane, the water pressure is greater along the straight bottom,while the curved surface of the shark’s body increases the distance the waterhas to travel, resulting in lower pressure across the shark’s top.
This pressure differential helps draw the water out of the baskingshark’s gills and allows the basking shark to be only filter feeder shark thatrelies solely on the passive flow of water through its pharynx to feed. Otherfilter feeder sharks, the whale shark and megamouth shark, assist the processby suction or actively pumping water into their pharynxes.
With this in mind, Reale designed his ‘Strait Power’ turbine with adouble converging nozzle or an opening within an opening. The water enters theturbine through the first opening and the second nozzle – like the shark’sgills – compresses the water and creates a low-pressure zone to draw the waterthrough and generate more energy.
Reale came up with the design for his senior project at the College forCreative Studies (CCS) in Detroit and recently had the opportunity to put it tothe test at the University of Michigan’s (UM) Marine Hydrodynamics Laboratory.The UM researchers with whom Reale collaborated were interested as they hadbeen working on something similar to provide power for remote research camps inAlaska
Subjected to 200 hours of testing in UM’s 100-yard-long (91 m),22-foot-wide (6.7 m), 10-foot-deep (3 m) tow tank, Reale’s 900-pound (408 kg)turbine model made mostly of wood, screwed together and sealed with marinepaint came out looking battered and bruised. But the results were promisingwith the researchers saying the design improved the power output of a singleblade by around 40 percent – a figure that Reale expects to improve upon withfuture versions.
Reale has filed a patent for the technology and has designed fivepotential commercial uses of the Strait Power system ranging from a portable andcollapsible version for charging small electrical devices designed for outdoorand military use, up to industrial versions with 10-foot (3 m) diameter bladesfor powering high-power electrical generators of 40,000 watts and higher.
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