Optimization and analysis of self-starting capabilities of vertical axis wind turbine pairs: A CFD-Taguchi approach
Esmaeel Fatahian, Rakesh Mishra, Frankie F. Jackson, Hossein Fatahian
Abstract
Optimizing vertical-axis wind turbine (VAWT) pairs is vital for addressing future energy needs, given that their power and aerodynamics are notably affected by wake interactions. This study investigates the self-starting behavior of adjacent rotors, using dynamic Computational Fluid Dynamics (CFD) start-up models with variable angular velocities. A Taguchi-based design of experiment (DoE) methodology, coupled with Analysis of Variance (ANOVA), is employed to optimize design parameters for rotor pairs, enhancing self-starting characteristics. Results demonstrated that the angle between adjacent rotors (factor D) strongly affected the start-up time of second rotor, while blade number (factor B) had least impact. In optimized layout, the downstream rotor (rotor 2) self-started faster than the upstream rotor (rotor 1) at a lower angular velocity of 57 rad/s, indicating the ability of rotor 2 to initiate self-start at a lower tip speed ratio than rotor 1. However, start-up time of rotor 1 is also influenced by rotor 2, which accelerated later than a single rotor. In optimized layout, the wake zone of rotor 1 shifts downward, recovers significantly, and reduces in size by 50% compared to a single rotor. This allows for more rotors in designated zones, benefiting from increased momentum and enhancing wind farm layout design.