An Experimental Study to Improve the Performance of Three-Straight Bladed Darrieus Vertical Axis Wind Turbine

In general, Vertical Axis Wind Turbines VAWTs have very important advantages, the most important of which is that they receive wind from any direction without orientation. The purpose of this work is to install Savonius hollow turbines with Darius type wind turbines with vertical axis and straight blades to reduce the weakening of the initial operating capacity of Darius turbines with Straight blades to reduce the weakening of the initial operating capacity of Darius turbines. The novelty and importance of this study is the possibility of using the Darius wind turbine in environments or places with low wind speeds in a more effective way to generate energy. In addition, one of the advantages of VAWTs is that they are simple to manufacture and low in cost. One of the solutions to address the problem of the Darrieus WT, which cannot rotate and does not respond to rotation in the field of low wind speeds, is the use of a combined rotor. In this research paper, the Savonius WT used to increase and improve the efficiency of the 3- Straight Bladed (3-SB) Darrieus WT by combining them together in a way that ensures their rotation on one axis of rotation. A combined Darrieus-Savonius (DS) is a sort of VAWT with numerous points of interest over individual Savonius or individual Darrieus WT, such as superior proficiency and beginning torque than the Darrieus rotor alone. Because of what was mentioned above and in order to solve the Darrieus problem in low wind speed, two models of the WT were designed and manufactured, one of which was a simple Darrieus with 3-SB Darrieus (NACA0012) and the other a combined three blades turbine of the DS, the Darrieus placed above the Savonius rotor. These two models of the WT were tested in a subsonic wind tunnel, the various parameters namely; total power, TSR and power coefficient were calculated. From the present investigation, it is seen that with combined DS wind rotor, the total power and power coefficient start increasing. The maximum power coefficient of 40% was obtained at a combined WT at a wind velocity of 5 m/s. However, while comparing the power coefficients () for a simple Darrieus-rotor with that of the combined configuration of the DS rotor, it observed that there is a definite improvement in the power coefficient for the combined DS rotor at the same wind velocity. The combined DS rotor provided power of 8.2 watt, which is higher than the power for a simple Darrieus rotor, which is 2.43watt, under the same test conditions.