Whether the Darrieus Rotor with Straight-Blades or Curved-blades is the Best, in Terms of Aerodynamic Efficiency

Abstract

An essential part of any wind turbine system is the rotor because it is the component that is in direct contact with wind and converts its kinetic energy into mechanical power. Then, it can either use this mechanical power directly to run some machinery, or you can use it to run an electricity generator and get electricity. One such turbine which is ideal for small-scale applications is the Darrieus wind turbine. This turbine has two blade configurations, straight or curved. This study aims to figure out the influences of these two blade configurations on the aerodynamic performance of the wind turbine. The engineering geometric shape of a parabolic Darrieus rotor was selected with certain dimensions, in this study it called P-D, and then a straight blade Darrieus rotor was extracted from it, in this study it called S-D1, similar to that of a parabolic in terms of rotor diameter and rotor height values, number of blades, blade section length and its type. Thus, a geometric similarity was obtained between the two rotors in terms of height to diameter ratio value and solidity value. Another rotor called S-D2 was also extracted and it is similar to P-D in terms of blade length, which means that the parabolic blade is straightened. There is also a similarity in solidity, and therefore it can be said that the masses of the rotors P-D and S-D2 are equal. This is the methodology that was followed to make the comparison in terms of aerodynamic. This analysis is done by developing a computer program that is based on mathematical model called multi-stream tube which modified to apply on both configurations of Darrieus turbine. The straight-bladed configuration is the best, according to this study.