Authors :
Tshepo S Sithole; Vasudeva R Veeredhi; Dr. Thembalani Sithebe
Volume/Issue :
Volume 7 - 2022, Issue 12 - December
Google Scholar :
https://bit.ly/3IIfn9N
Scribd :
https://bit.ly/3W1aVKx
DOI :
https://doi.org/10.5281/zenodo.7444983
Abstract :
Theoretical algorithms, such as computational
fluid dynamics (CFD), blade elementary method (BEM)
theory, and the vortex wake system (VWS) have been
implemented in the design of aerodynamic wind turbines.
On these theoretical methods, the (BEM) theory proved to
be the best method in optimising HAWT blades and is thus
the most commonly used approach in modelling and
constructing small wind turbine blades. This paper will
primarily focused on designing and optimizing the type of
aerofoil required for improving the pitch angle of the rotor
blades, and for determining the number of blades
necessary to optimise the power output at various wind
speed using BEMT. A NACA-4412 type aerofoil was
chosen as the departure point for the blade design. Various
pitch angles of 6°, 10° and 12° were chosen at an optimum
angle of attack of 5°, 7° and 9°. A blade radius of 0.8-
1.0 m and chord length of 0.08-0.1 m were subsequently
chosen for Designs 1, 2 and 3 respectively at various low
wind speeds. At average wind speed of 0 - 2.3 m/s (8.28
km/h), 3-blade, 5-blade and 7-blade sets were designed and
optimized for performance. During the design of the wind
turbine blades, it was predicted that at various wind
speeds, the rated output would be 7.5 W, 20 W and 40 W
respectively Design 1, 2 and 3. The results for Design 1,
with a blade radius of 0.85 m, a chord length of 0.06 m near
the rotor hub, with a pitch angle of 6° at the rotor hub and
a tapering off to about 1° at the blade radius tip of the
blade, produced a maximum output power of 8.2 W at
4.2 km/h wind speed, and Design 2, with a blade radius of
0.95 m, a chord length of 0.08m near the rotor hub, with a
pitch angle of 10° near the rotor hub and a tapering off to
1° at the blade radius tip of the blade, yielded a maximum
output power of 12,5 W at 4.2 km/h wind speed and lastly
Design 3, with a blade radius of 1m, a chord length of 0.1m
near the rotor hub, with a pitch angle of 12° near the rotor
hub and tapering off to 2° at the blade radius tip of the
blade, generated a very useful power output of 39.5 W
during testing. The maximum power output was achieved
at an average wind speed of 1.17 m/s (4.2 km/h).
Keywords :
Small Wind Turbine’s, Design, BEM Theory, Yielded Power.
Theoretical algorithms, such as computational
fluid dynamics (CFD), blade elementary method (BEM)
theory, and the vortex wake system (VWS) have been
implemented in the design of aerodynamic wind turbines.
On these theoretical methods, the (BEM) theory proved to
be the best method in optimising HAWT blades and is thus
the most commonly used approach in modelling and
constructing small wind turbine blades. This paper will
primarily focused on designing and optimizing the type of
aerofoil required for improving the pitch angle of the rotor
blades, and for determining the number of blades
necessary to optimise the power output at various wind
speed using BEMT. A NACA-4412 type aerofoil was
chosen as the departure point for the blade design. Various
pitch angles of 6°, 10° and 12° were chosen at an optimum
angle of attack of 5°, 7° and 9°. A blade radius of 0.8-
1.0 m and chord length of 0.08-0.1 m were subsequently
chosen for Designs 1, 2 and 3 respectively at various low
wind speeds. At average wind speed of 0 - 2.3 m/s (8.28
km/h), 3-blade, 5-blade and 7-blade sets were designed and
optimized for performance. During the design of the wind
turbine blades, it was predicted that at various wind
speeds, the rated output would be 7.5 W, 20 W and 40 W
respectively Design 1, 2 and 3. The results for Design 1,
with a blade radius of 0.85 m, a chord length of 0.06 m near
the rotor hub, with a pitch angle of 6° at the rotor hub and
a tapering off to about 1° at the blade radius tip of the
blade, produced a maximum output power of 8.2 W at
4.2 km/h wind speed, and Design 2, with a blade radius of
0.95 m, a chord length of 0.08m near the rotor hub, with a
pitch angle of 10° near the rotor hub and a tapering off to
1° at the blade radius tip of the blade, yielded a maximum
output power of 12,5 W at 4.2 km/h wind speed and lastly
Design 3, with a blade radius of 1m, a chord length of 0.1m
near the rotor hub, with a pitch angle of 12° near the rotor
hub and tapering off to 2° at the blade radius tip of the
blade, generated a very useful power output of 39.5 W
during testing. The maximum power output was achieved
at an average wind speed of 1.17 m/s (4.2 km/h).
Keywords :
Small Wind Turbine’s, Design, BEM Theory, Yielded Power.
