Máquinas eólicas de eje vertical
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Savonius


Rotor Eólico Savonius de eje vertical


Parametros del rotor Savonius para incrementar su eficiencia. Abstract.


Parametros del rotor Savonius. Introducción.

1 Introduction.

When a wind site is chosen to install wind machines in order to produce electricity, it is expected to extract the maximum possible energy from the wind. The choice of an "aerogenerator" should be done via this sole criterion.
Wind turbine are generally designed for a nominal working point, i.e. for a given velocity of the wind which is obviously linked to an attended delivered power. Consequently, the notion of the produced energy, for example for a whole year, is often forgiven; the notion of installed power, or that of installed power per square-meter of cross wind, are generally preferred. This idea incites the operators to prefer wind machines of higher efficiency for the equipment of wind sites.

The choice of a wind machine is obviously based on its energetic performances. To simplify our presentation, we have drawn the working curves of main conventional wind turbines (figure 1). These curves, extracted from the monograph of Wilson and Lissaman [1], give the power coefficient Cp , ratio of the aerodynamic power of the turbine to the power of the incident wind, as a function the speed ratio l. l is also called the velocity coefficient and is equal to the ration of the tip peripheral speed to the wind velocity.

The power coefficient is directly linked to the global efficiency of a wind machine.
The curves of figure 1 show that the fast running horizontal axis wind machines (two- or three-bladed airscrew) have incontestably the best efficiencies. Consequentely, theses machines are systematically chosen for the equipment of wind sites. On an other hand, the Savonius rotor [2], which is a slow running vertical axis wind machine (l » 1.0)
has a rather poor efficiency : Cp » 0.2.


Parametros del rotor Savonius. Investigacion.

Parametros del rotor Savonius. Resultados.