Performance Characterization of Cyclic Blade Pitch Variation on a Vertical Axis Wind Turbine

摘要

This study characterizes the effects of cyclic blade pitch actuation on the efficiency and operability of a high-solidity vertical axis wind turbine (VAWT). A VAWT utilizing a cam and control rod mechanism to prescribe the pitch dynamics is constructed and tested in MIT's Wright Brothers Wind Tunnel over a wide range of design and operational variables. The experiment concludes that a tuned first-order sinusoidal actuation system can achieve a maximum absolute efficiency of 0.436, an increase of 35% over the optimal fixed-blade baseline configuration, with self starting capabilities and drastically improved performance at a wide range of suboptimal operating conditions. This performance is comparable to that which as been previously reported for more structurally demanding variable pitch VAWT designs of lower solidity and fixed pitch designs operating at higher tip speed ratios (TSRs). Additionally, a low order order computational model is found to accurately predict the trends and maximum efficiencies of the system.