Employability of vertical axis crossflow whirlybird rotor as hydrokinetic turbine and its performance prediction corresponding to different design parameters

In this study, the employability of the vertical axis crossflow whirlybird rotor as a hydrokinetic turbine is examined. Further, design parameters are optimized that affect the rotor performance. Torque, power, power coefficient and torque coefficient are calculated at various angular speeds and tip speed ratio (TSR) by Numerical method using computational fluid dynamics (CFD). Further different results of numerical analysis are validated with the experiment. Numerical analysis results shown in the form of pressure contour, velocity contour and velocity vector are served to explain the flow phenomenon surrounding the rotor. Subsequently, effects of the number of blades, blade angle, rotor diameter, rotor height, blade length and free stream velocity on the performance of rotor are also investigated. It is found that with the increase in blade number, blade angle and blade length, the maximum torque coefficient and maximum power coefficient increase up to a certain limit and then drop drastically. In view of these, the optimal blade number, blade angle and blade length are determined as 27, 75 and 30 mm respectively for the present design configuration of the rotor. Moreover, the analysis suggests that the rotor diameter, height and free stream velocity have a substantial influence on turbine output.