Theoretical performance of a straight-bladed cycloturbine under four different operating conditions

The theoretical performance of a wind-turbine-load system is analyzed under conditions of varying types of loads, using a Cycloturbine as the experimental machine. The variation of the angle of attack and torque with the position of the blade was calculated. It is found that at certain locations, abrupt changes are necessary in order to optimize the angle of attack, a feature which is not mechanically desirable. Additionally, the torque is angularly divided according to the number of blades, but varies also as the angle of attack, which can be either favorable or not, depending on the blade position and ability to adapt. A function to determine the point of constant power coefficients is defined for a constant wind velocity and rotation speed. The effect of the amplitude of the angular pitch variation on performance is discussed, as are the effects of a variable wind velocity on performance and on the power coefficient. Attention is given to operations when coupled to a water heat churn, with account made of constant and variable wind speeds. Operation of a wind turbine at an optimum tip speed ratio is concluded to maintain maximum efficiency, regardless of the magnitude and frequency of wind velocity fluctuations.