This work presents a study of the vertical Savonuis wind rotor, including design,
construct, and test, with a new configuration parameters, to improve its performance.
The new rotor's parameters consist of two stages-four blades (main and
secondary). The blades are arranged such that, leaving a separation gap between the
inner ends of the blade to get the benefit of the air flow reaction energy in the bucket
on the exit side, The secondary stage height equals 1/4 of the rotor height. The blades
of the second stages are shifted by 45 degrees from main stage on the same axes.
It is expected that the secondary stage assists the starting of the rotor and prevents
the counter torque to appear in the static and dynamic torque cycle.
This Savonius rotor turbine was tested on the subsonic wind tunnel model AF100
made by TecQuipment Ltd., with the range of wind velocities (U=0 to 20 m/s), on no
load, it is found that the rotor started rotation at wind velocity of 1.2 m/s. The test of
static torque Ts was done under constant velocity of 12 m/s, and dynamic torque T
was performed under air velocities of (U=10, 12, 14, 16, and 18 m/s).
Testing results show that the Savonius rotor turbine can start at low wind velocity
from any position. The static torque coefficient Cts was improved, with peak to peak
value of (17.2 – 39) % in the positive range during cycle of α=180º. The maximum
power coefficient approach to (Cp=16% at λ= 0.8). Comparing the performance of
this turbine with the others show that the power and torque coefficients are improved.