Ultralight Wind Turbine Test/ Prueba de Turbina Eólica Ultraliviana

[danielcastez]

You may read the full article here:  daniel.castez.com.ar

[danielcastez]

Taking a value of lambda for peak power extraction (lambda is the relationship between tangential speed and wind speed) of 6, which is a typical value for commercial models (our turbine has a lambda of 5.4) it is easy to calculate its power (W = T x w, where T is torque in Nm and w is angular velocity in radians per second)

W = 2 Nm x 30 r/s = 60 W

[danielcastez]

Using these data, it is easy to estimate mechanical power attained by the turbine at this wind speed, at a rotation speed of 3.8 rps and a torque of 12 Nm (this torque is the one attained at peak power in this wind). Mechanical power is then:

W = 12 Nm x 24.3 r/s= 291.6 W

We can compare this power with that of a commercial three bladed turbine of the same diameter (2 m) which at a wind speed of 5 m/s develops a torque of around 2 Nm

[danielcastez]

Wind speed during the test was measured b y means of a hot-wire anemometer that was provided by the Fluidodynamcs and Boundary Layer Lab of the Faculty of Aeronautical Engineering at the UNLP. Engineers from this lab performed all the wind speed measurements during the tests. This acceleration implies a high start-up torque (around 8 Nm) even at this small wind speed

[danielcastez]

When we were shooting this video, the turbine was exposed to a 4.5 m/s wind speed and it is easy to see how it accelerates to achieve maximum speed of rotation for this wind (angular acceleration was estimated to be 0.8 r/s2 at start-up increasing to 1.2 r/s2 when the turbine reaches angular velocity corresponding to peak power at this wind speed) of 5.3 rps, in spite of the fact that it has to drive at the same time a gear-box (x 4) and a generator (at no-load condition during this first test)

[danielcastez]

This is due to the materials used in their construction, ie polyester resin and glass fiber. The commercial model will have blades made of aluminum foil on an aluminum frame.thus achieving a weight reduction of 70% ; thus, the new blades will weigh 8.5 x 0.3 = 2.55 kg. This kind of construction is current for wings of ultralight planes.

[danielcastez]

English version

Ultralight Wind Turbine Prototype

Technical characterístics

The turbine that is shown in this video has a diametre of 2 m. It has 24 blades 0.34 m long and 0.1 m wide at the tip (@ r=1m) Beta angle at blade tip is 7º. At the other end of the blades, the beta angle increases to 10.5º, which translates into a twist angle of 3.5º . The turbine weight is 16 kg while that of the blades is 8.5 kg.