No abstract

Abstract:The Savonius wind turbine is a type of vertical axis wind turbine (VAWTs) that is simply composed of two or three arc-type blades which can generate power even under poor wind conditions. A modified Savonius wind turbine with novel blade shapes is introduced with the aim of increasing the power coefficient of the turbine. The effect of blade fullness, which is a main shape parameter of the blade, on the power production of a two-bladed Savonius wind turbine is investigated using transient computational fluid dynamics (CFD). Simulations are based on the Reynolds Averaged Navier-Stokes (RANS) equations with a renormalization group turbulent model. This numerical method is validated with existing experimental data and then utilized to quantify the performance of design variants. Results quantify the relationship between blade fullness and turbine performance with a blade fullness of 1 resulting in the highest coefficient of power, 0.2573. This power coefficient is 10.98% higher than a conventional Savonius turbine.

No abstract

The long wake of a wind turbine has a significant impact on the performance of downstream turbines. Under the inspiration of migrating geese flying in a V or I formation to save energy, a novel wake energy reuse method is proposed to optimize the layout for Savonius-type vertical axis wind turbines (S-VAWT). VAWT wakes include a series of high speed and energy zones. On both sides of the upstream turbine, 16 7  transient two-dimensional numerical simulations are performed with Fluent to investigate wake structure, interaction effect and power coefficients (C p) of downstream turbines. Based on Kriging Method, a response surface model (Surrogate model) is created to describe the relationship between the optimization objective C p and layout positions. Finally, particle swarm optimization algorithm is applied to find the optimal relative layout position (5.25m,-2.18m) of the downstream turbine. The optimal position is located in the periodic high speed zone of the wake on the advancing blade side. And the optimal position is suitable for multi-turbines in a large wind farm. The optimization results show that C p of downstream turbines at optimal layout position is significantly increased from 0.2477 to 0.3044 (22.89% higher).