The Benefit Using a Circular Flow Disturbance on the Darrieus Turbine Performance

Abstract

Darrieus is a vertical-axis type turbine with difficulty rotating at low current velocity. Adding a circular flow disturbance in front of the Darrieus turbine can improve the self-start capability. This study has aimed to improve the turbine's performance by identifying the configuration and diameter ratio of flow disturbance. Numerical modelling in transient conditions has been done by using Computational Fluid Dynamics (CFD) software with a sliding mesh technique. There are four diameter ratios ds/D 0.1, 0.3, 0.5, and 0.7 and three variations of cylinder position. Each combination variation has been simulated at current velocity of 0.3, 0.4, 0.5, and 0.6 m/s. As a result, depending on where the cylinder installation is located, the circular flow disturbance has an effect that might hinder or enhance the performance of the turbine. The best result is at the flow disturbance position of -60o with a diameter ratio of ds/D 0.5 at TSR 1.43. The maximum coefficient of power (Cp) value has increased by 38%. Furthermore, at overall current velocities with a range of 0.3–0.6 m/s, the average Cp has increased of 30% with the best diameter ratio usage of ds/D 0.5.