Highlights
Directory

Last Home Page Update: Jan/3/2012

Concepts Under Review
(sketches):


Offshore 10 MW Two Rotor
Wind Turbine
With Rotor Overlap


Hi-TSR
*Double Element* Blade
(Two Blades - One Root)
Source image: CalWind
Nordtank 65 in
Tehachapi with a
second blade superimposed


Flange Detail On Above Blade

Home brewed small turbine blade rotors showing surprising promise:


Note the large generator (one horsepower). Click on Video One of the videos to the right to see it run. This blade rotor runs so efficiently and with such high speed that it was found to
bring the wind to a halt behind it.


Talk about fun for experimenters - blades made from metal yardsticks found in the hardware store with "bladelet" add-ons at the tips.

Another view. Easy and fun to make. Plenty of speed and power on the small generator.

An item in the "Things Under Review" section provides a math derivation of a factor equal to less than one - can be as low as 2/3 - to be applied to verticals wind turbine (aka VAWT) blade swept areas in equilibrating their power production to that of equivalent horizontals blade swept areas.

See the dozens of links provided on the Home Links and Projects page to discussion threads on energy topics involving small wind, a continuing story of development at the grass roots level!

See the Wind Turbine Upgrades, on a featured web page herein. The many wind turbines of earlier design and lower ratings occupying wind energy projects can be upgraded with blades reflecting current technology. A good example are the Nordtank 65s seen here. The turbine on the left has the original blades. The same model turbine on the right has newer blades redesigned by U.S. National Laboratory prime contractors. Experience gained over the past few years have proven the value of the redesign..............

Latest New Items

Check here for what's new!
note: text size adjustments on your browser toolbar sometimes advisable


    Air In Motion Does Not Want To Be Deflected!
            The Kutta-Joukowsky Condition Invalidated
The image on the left is a photograph of streamlines around an airfoil. The flow,
due to its momentum, is not being fully deflected and is breaking off before
reaching the trailing edge, demonstrating what is all too often not given full
enough consideration in blade design. Air in motion resists being deflected.

Airflow angular deflection is all-important in wind energy, where it directly
impacts energy conversion. Airflow angular deflection tends to be greater as
produced by the blades of wind turbines than the wings of aircraft. Conflicting requirements enter the mix due to drag
considerations but it can be said that obtaining good angular deflection requires added attention in wind turbine blades.
Note that the Coanda Effect is maintained here. Turbulent stall is not occurring. The flow beneath the airfoil is taking
a sharp turn around the trailing edge and reaches the upper surface before leaving. The Kutta-Joukowsky Condition,
a basic premise in Fluid Dynamics study and a requirement for the determination of the gamma circulation, G , and,
accordingly, the lift coefficient, is not being met, casting doubt on the benificence of earlier theories.

IntegEner-W has taken steps to address this issue. A wind turbine blade design that reinforces airflow deflection above that
of typical blade designs has been tested on a small scale with good results and submitted to the USPTO for filing and the
first stage of legal protection. See also the revised comment at the bottom of the page.

    The Surprising Airfoil Aspect Ratios - Both In Aviation And Wind
Here is the story. Roughly defined, the aspect ratio is the airfoil length divided by its average
chord. Aircraft wings of high aspect ratio, that is, that are extra long and of a narrow chord,
deflecting the incident airflow downwards at a small angle, can support the fixed weight of
an aircraft with less power from the engines. Aircraft wings that are much shorter but have a wider chord pitched at a
larger angle for greater airflow deflection require, to support the fixed weight of an aircraft, a larger amount of power
from the engines...........Click here to continue

STREAM FUNCTION CFD SOFTWARE BASED ON ABBOTT & VON DOENHOFF - Software programs that draw computer screen images such as this airfoil (using the Joukowski model) and stream function
y(x,y) line patterns such as these to the right, comprising TEN progressive CFD programs in BASIC, are now available. The example output screens demonstrate a flow pattern under study. Up to 7 input parameters can be adjusted. A BASIC compiler is also included (normally supplied in MS Windows). This help is
invaluable for the teaching and learning of material in fluid dynamics textbooks as applied to wind energy problems.
To download the .2 MB directory, click here.

Engineering textbooks Theory of Wing Sections by Abbott and von Doenhoff, An Introduction to Fluid Dynamics by G. K. Batchelor, and Advanced Mathematics for Engineers by Reddick and Miller are well known as being classics covering Fluid Dynamics Theory. As an aid in elucidating the material and converting the analyses more directly to wind energy while retaining their rigor, a sequence of written papers in .pdf format has been placed on-line. To download the 3 MB directory, click here.

TEST SERIES VIDEO ONE This is the same 51 inch diameter blade rotor under test as seen in video two just below mounted on the 14 foot wooden tower and powering a much larger generator now than the one previously used. It is a Baldor one horsepower 90 volt DC motor used as a generator. Each blade consists of one 18 inch metal cambered blade plus one 24 inch flatter sheet metal second blade with a gap between connected together with struts designed to give the rotor more airflow deflection capability. The load is now much greater, about two dozen 12 volt lights paired in series, including many 50 watt halogen auto headlights. Just click on the image for a fast download of the 530 kb video of the blade rotor powering the lights.


TEST SERIES VIDEO TWO This is the 51 inch diameter blade rotor described above during an earlier test mounted on the wooden tower and powering an AMETEK-type 30 volt DC motor available as a generator. Normally such a blade rotor diameter would be compatible with a generator of this rating but the "doubled blades" design feature created a runaway problem that was corrected with the larger generator. The load here consisted of about 17 small 12 volt lights, about 100 watts total. Just click on the image for a fast download of the 380 kb video.



TEST SERIES VIDEO THREE This is the H-MicroRotator - the horizontal axis small wind rotor. Plenty of rotational speed. Even a friction drive speed converter. Plenty of torque. Watch the generator spin and the lights light up. Just click on the image for a fast download - about 510 kb.

Also see the VIDEO of the V-MicroRotator ("V" for "Vertical" axis) running in the wind on the Special Offers page.

Hello. I am "Dutchy" the Windmill. In the U.S. a well-known fast food restaurant offers a "quarter pounder" hamburger. How is this described in the metric system around the world? Metrics uses kilograms for most weights and so it might be called the "hundred grammerburger". This mass has the weight force in metrics of about one newton and so this "McMeal in a bun" could also be called the "newtonburger" or "newtonianburger". When eating one, be careful to observe Newton's Laws! (Just kidding.) Air is the same way. A quarter pound of air occupies just a little over 3 cubic feet. Remember this - a cubic yard of air weighs up to two pounds, the same as a quart of water........

"In conformance with the latest aerodynamic ideas (NASA momentum-based aerodynamics), puts the basic forces acting on wings and blades - and their wonder - to rest!" This caption on the cover says it all. The IntegEner-W 30 page "Aerodynamic Lift as it applies to Birds, Aircraft, Wind Turbines" booklet is a contributor to theories based on readily comprehended averaged-flow momentum conservation concepts and will quickly bring up to date those who have not yet been exposed to them. The booklet is available as an immediately downloadable document in both PDF and HTML format, including cover pages and in full color. Just click on an image.

Several sites where can be found electrical energy generating equipment, particularly diesels and gas turbines, of ratings suitable for standby utility-grade application near wind energy projects are the following:

Belyea   General Electric   MTU OnSite Energy   Wabash   Waukesha

Two important periodicals that cover the latest on the renewables in the electrical energy field can be found at the following locations:

Windpower Monthly News Magazine     Sun & Wind Energy Magazine

An overlooked idea on transportation that would interest EV and pedal-power supporters (recommended for its to-be-desired mundane appeal) is:    BikeTrans

Progress continues to be made with geothermal heat pumps for occupied spaces heating and cooling. The ground has a high thermal capacity and is a deep source of heat flow and, as long as adequate measures are taken to limit wall and roof heat energy loss or gain, can be an efficient method of temperature control. Two associations that provide information on this technology are the International Ground Source Heat Pump Association and the GeoExchange. A supplier:

Econar

Compact fluorescent lights are now improved and four times as efficient as the same brightness of incandescents. Much can be said in their favor, including significant impacts on electrical power generation once adopted by homeowners and businesses everywhere. Several sites that describe them (now including dimmable varieties and the new "Mini-Spirals" that are as small or smaller than ordinary bulbs) are:

Lights Of America      General Electric      Sylvania      Philips     

Sylvania also has the new Light Emitting Diode (LED) super bulbs.

Wind Theory
It should be said at the outset here that aviation's "lift force" is given little attention and coverage herein. The "lift force"
is defined as a force always at right angles to the incident wind ahead of the leading edge of the airfoil and does not fit
as well into the framework of wind energy as it does into that of aviation. In a true theory of wind energy the correct
forces to be determined from the computational fluid dynamics (CFD) are the blade driving force and the blade lateral
force, i.e. in the rotor axial direction. Some chapters are provided below, written into this website page, of the basics of
a "Newtonian" approach to the wind energy CFD, which provides these forces directly. It rests on the use of averaged
velocity vector diagrams that consider a wind turbine blade cross section fixed in place while the wind is allowed to
vary in speed and direction relative to it and might be called "pure deflection" aerodynamics.

Chapter   1     Derivation Of The Basic Airflow Force Equation
Chapter   2     Drawing The Line
Chapter   3     Thermal Combined Cycle RDF
Chapter   4     Geese And Ducks
Chapter   5     Home Of The Big Wind
Chapter   6     Aerodynamic Theory Revisited
Chapter   7     Homework Assignment
Chapter   8     The Horizontals - Also Negative Pitch Angles
Chapter   9     The Verticals
Chapter 10     Full Summary Analysis

See also the on-line paper published for aviation but with some relevance to wind energy,
"The Newtonian Description of Lift of a Wing.....", February 2009, by Anderson and Eberhardt in .pdf format.

Wind turbine blade lengths have been increasing and are beginning to reach a point of diminishing returns. Specific
outputs in terms of watts per square meter of swept area are dropping to 300 watts/meter^2 and even 200 watts/meter^2.
Variable rotation rates have been of assistance in maintaining high capacity factors. It is believed, based on small scale
testing, that refinements to theories can provide further material improvements that have not yet found acceptance.
Aerodynamics fluid flow is indeed a fascinating study. Some might say it is also prone to varied interpretations delaying
consensus.