Research and optimization of a built-in entity vertical axis wind turbine by variable pitch strategy

Abstract

Blade pitching technology plays a key role in solving the low power coefficient problem of the vertical axis wind turbine(VAWT). The study optimizes the variable pitch strategy for a specific wind turbine (i.e., the built-in entity VAWT) integrated into a building by computational fluid dynamics (CFD) simulations. The diameter of the built-in entity is set to 50% of the turbine, and the tip speed ratio is set to 1.8. The proposed pitching optimization strategy in this study is based on the dual multiple stream tube (DMST) model in the built-in entity VAWT. The objective of this study is to (i)Comparison of the DMST model variable pitch strategy with the fixed pitch angle strategy for the built-in entity VAWT, and defined a variable pitch strategy for the built-in entity vertical axis wind turbine. The variable pitch strategy is upwind rotation and downwind fixation (URDF model), which means variable pitch in the upwind area using the DMST model and fixed pitch in the downwind area. (ii) Comparing the moment efficiencies of keeping different fixed pitch angles from −6°to 6°in the downwind area of the URDF model on the built-in entity VAWT, it was determined that the URDF model is optimal when keeping 2°in the downwind area. The results show that compared to the fixed pitch angle and the variable pitch strategy using the DMST model, the power coefficient of the built-in entity VAWT is improved using the URDF model variable pitch strategy. The best power efficiency is obtained by keeping the downwind area of the URDF model at an angle of 2°, which increases power efficiency by 19.21% compared to keeping the fixed pitch angle. The results of this study can improve the performance of built-in entity VAWT and provide an analysis method and optimization strategy to improve the efficiency of wind energy utilization on buildings.