MATHEMATICAL IMPLEMENTATION OF EFFECT OF INCREASE IN DIVERGENCE ANGLE OF A DIFFUSER ON SPEED AND POWER GENERATION OF HAWT USING DISK THEORY

Summary

Harnessing wind energy to turn a turbine for power generation requires concentration of the wind at high velocity to give
maximum and steady power output. Mathematical relationships are used to analyze the variation of the pressure and
velocity of the flow regime in the conical duct. The pressure and velocity magnitude varies oppositely, pressure increases
as velocity decreases. This revealed that power extracted by horizontal axis wind turbine (HAWT) is the product of the
volume flow rate of air through the turbine and the pressure drop across the blades, which is a result of the thrust of the
blades. The mathematical model uses disc theory to predict appropriate position of rotor for maximum power production.
The diffuser angles considered are 40
8
0
120
160
and 200
. Energy conversion starts at a certain angle say 40
and will
increasing until a certain angle of about 200 and it will begin decline. As the angles are increased the power output of
the turbine also increased until when it get to angle 200 then it begin to decline. The turbine operation exhibits a
reasonable range of tip speed ratio and high efficiency. The proposed method suggests that an increase in CP of about
0.035, which is about a 27%, for open angle of 120
, 32% for open angle of 160 and 38% for open angle 200
increase in
aerodynamic efficiencies, were attainable with the DAWT concept. This improvement is primarily due to efficient
extraction of energy (wind) blowing near the hub of the main rotor, but in part also due to the addition of another energy
extracting device called diffuser augmented system.

Index Terms

Browse additional articles authored by one or more contributors to this paper.