[getsmart-l] Wind Turbines - mimic humpback whale's fin

[Gloria Boxen]

http://tyler.blogware.com/blog
Monday, May 14
View Article  A whale of a tale
by Tyler on Mon 14 May 2007 01:45 PM EDT

My Clean Break feature (Tyler Hamilton, A whale of a
tale: Humpback flipper may be the key to better wind
turbines, Toronto Star, Mon May 14, 2007,
http://www.thestar.com/Business/article/213475) this
week is a story about a Toronto company called
WhalePower Corp. that has designed a new type of
wind-turbine blade that dramatically improves turbine
efficiency. 

What's unique about the design is that it mimics the
aerodynamic feature of a humpback whale's flipper,
which has bumps or "tubercles" along its leading edge.
Scientists have found that the tubercles reduce the
drag and increase the lift on the flipper, having the
effect of delaying stall. Earlier studies have
attempted to apply this principle to airplane wings
and rudders on boats, but WhalePower is adapting it to
blades for wind turbines, fans -- essentially anything
with a rotating blade that moves through air or fluid.


The co-founders (Frank Fish, Stephen Dewar) of
WhalePower claim their blade captures more of the
wind's energy at lower speeds where conventional
turbines tend to stall. 

For example, a turbine equipped with WhalePower blades
could produce the same amount of electricity from 5
metre-per-second winds as a conventional turbine tends
to produce with winds blowing at 8 metres per second.
This means the humpback-designed turbines could allow
wind farms to produce more kilowatt-hours a year,
improving the business case for wind farms.

The big question is: Even if this is a superior blade
design, would the industry be willing to change? Given
turbine manufacturers are already having a tough time
keeping up with demand, there's not much incentive in
radically changing the design of their product for the
benefit of customers. And while WhalePower says it has
a way to retrofit existing turbine blades, there's the
question of voiding the warranty -- something most
wind-farm operators are reluctant to do.

All that said, it's a neat company that's bound to
attract further attention from investors and the
media. And the approach could represent a way for a
newcomer to the wind-turbine manufacturing market to
distinguish itself from the competitive pack.


Patent:
http://www.wipo.int/pctdb/en/wo.jsp?IA=WO2006042401&DISPLAY=STATUS

http://www.wipo.int/pctdb/en/wo.jsp?IA=WO2006042401&DISPLAY=DESC
The turbine/compressor provides advantages in that the
additional lift generated by the rotor blades does not
contribute additional drag but rather, improves the
lift to drag ratio. As a consequence, since the rotor
blades exhibit lower drag, less structural strength is
required for the supporting towers in any given wind
environment. This of course translates into lower
costs. 

Also, by adjusting the orientation of the rotor blades
so that they are more steeply pitched into the fluid
flow, lift can be further enhanced. The enhanced lift
characteristics allow more power to be captured from
available fluid flows. 

The improved stall characteristic of the rotor blade
results in a reduction of drag thus, permitting the
rotor blade to operate over a wider range of fluid
flow rates and further increasing the amount of power
that can be captured from the available fluid flow. 

In addition, the shape of the rotor blades helps to
reduce span-wise pumping and hence, rotor tip
turbulence and thus, reduces noise.