The British company Stormblade Turbine is developing a new type of wind turbine that should be more efficient, less noisy and require less maintenance than the standard three-blade formula.
One of the most important problems of current wind turbines occurs when the wind speed is greater than 27 m / s (97 km / h): the rotor must be stopped, because a gyroscopic effect is then created in the shaft. 'training. This gyroscopic precession (property of a rotor by which the effect of a force tending to tilt the axis of the rotor is offset by 90 degrees from its point of application in the direction of rotation) tends to twist the rotor, this which increases the stresses on the blades and mechanisms, leading to ruptures.
Furthermore, if the wind speed is less than 7 m / s (24 km / h) the rotation of the rotor is too low to produce electricity.
The Stormblade Turbine, created by Victor Jovanovic, founder of the company, has a design similar to that of an airplane reactor: the blades are protected by a fairing which directs the air flow inside this turbine like an intake nozzle. However, this fairing is exposed to the wind and to the high rotational speeds of the air flow passing through it and can thus develop a "parachute" effect. The mast of the wind turbine is then subjected to extreme stresses. The mast must then be supported by reinforced scaffolding, which will require more floor space and increase the cost of the system.
The main innovation of the system therefore concerns the rotor part which is based on the turbine of a jet engine. According to Jovanovic: "Jet engines have evolved over the past 50 years to produce less drag, allowing the blades to turn faster." The aerodynamics of the system are therefore improved, which makes it possible to reduce and increase the speed of rotation of the rotor without having to undergo a phenomenon of gyroscopic precession. The efficiency of the Stormblade Turbine is expected to be 70% versus 30-40% for current three-blade models, which means this design exceeds Beltz's limit (59%) of maximum efficiency for wind turbines. Jonanovic estimates that his wind turbine will be able to produce electricity for a wind speed of between 3 m / s (11 km / h) and 54 m / s (193 km / h), thus doubling the usable speed range. Extending the speed range offers two major advantages:
- electricity production takes place more continuously;
- the power produced by these wind turbines is very high: it is proportional to the cube of the wind speed.
As the vanes are inside the fairing, noise from the gearbox should also be reduced. This particular configuration also makes it possible to reduce maintenance costs and preserve the avian life in the vicinity. In terms of visual impact, the sweeping surface of this wind turbine is less than that of conventional wind turbines. However, since the power produced is proportional to the area swept by the blades, the power delivered by a Stormblade Turbine should be less than that of conventional wind turbines despite faster wind speeds.
The prototypes tested so far have shown that the efficiency of the system is much higher than that of existing turbines (up to 3 times higher). The company is currently looking for funds and industrial partners. This system should be available on the market in 18 months to 2 years.