Windmill Shrouds and their use
Shrouds like those of jet engines cover some turbines. The use of a shroud is that the wind gets channeled. .
The equation for the power harnessed by a shrouded wind turbine is:
P(Pe) = ( QT ((p + (k) where P is the power,
Pe is the power extracted, ( is the turbine efficiency, QT is the volumetric flow rate of air on the turbine, (V/A)),(p + (k) is the change in pressure energy between the inlet and the exit of the wind turbine, and k is the cane in kinetic energy of a unit volume of air that passes through the machine.
A shroud is used for concentrating and diffusing the wind as it passes through a horizontal in shape access wind turbine, it helps in reduction of turbulence of the wind and directing it.
The main reasons for the use of a shroud are
a) A shroud increases the axial velocity of the turbine making smaller rotrs operate at high revolutions than usual.
b) The use of a shroud can greatly help in reducing tip-losses, and
The height of the windmill has to be given considerable thought, it should be high enough to tower above all the obstructions and still be able to sustain itself when the wind velocity is really high. The wind velocity close to the surface is usually the lowest, so the higher the windmill is, the higher will be the power generated by the windmill, since the wind speed would be generally higher than that of the ground.
The equation for the calculation of the windmill is:-
V1/V2 = (H1/H2)n,
Where V1 is the wind speed at the highest point of the highest blade, V2 is the wind speed at the lowest
point of the lowest blade, H1 is the height of the highest point, and H2 is the height of the lowest point. n is the index location of the site, a value that measures the roughness of the terrain.
