THE EFFECT OF NUMBER OF BLADES ON THE PERFORMANCE OF HELICAL-SAVONIUS VERTICAL-AXIS WIND TURBINES

This work presents the results of a series of experiments conducted on three different scaled-down Helical-Savonius vertical axis wind turbines (VAWT). systems. The work was aimed at investigating how the number of blades may affect the performance of the Helical-Savonius VAWTs. The first turbine consisted of two helical blades, the second turbine had three blades, and the third turbines had four blades. The work included a design phase in which the three dimensional (3D) geometry of each of three VAWTs were developed using a 3D drawing software. The 3D models were then uploaded to a rapid-prototyping machine to fabricate the VAWTs. The projected areas of each of the VAWTs were that of a rectangle of 4" x 6". A test setup was designed and developed to examine the performance of the scaled-down turbines. A 1.1 KW floor fan was used to simulate wind flow in the laboratory for testing of the turbines. A flow straightener was also designed and developed in order to minimize the turbulent flow of the air at the discharge opening of the floor fan. The test results show that the 3-bladed rotor design performs better than the two and four bladed turbines. Under the same wind speed conditions the 3bladed turbine produced 18% more power compared to the 2bladed turbine, whereas the 3-bladed turbine produced 30% more power compared to the 4-bladed turbine.