Optimization of Blade Mount Point and Pre-set Pitch in a Conventional Small Vertical Axis Wind Turbin

Among several categories of wind generators, small wind vertical turbines have gained more interest for their excellent adaptability to the urban environment in terms of visual impact and noise pollution. Being axisymmetric, these turbines are omnidirectional, which helps to respond well to variations in wind direction. In order to analyse the complex unsteady aerodynamic flow associated with the small vertical axis wind turbine (VAWT), computational fluid dynamics (CFD) is an attractive and powerful tool. The numerical model has been conducted by means of CFD analysis by solving Unsteady Reynolds Average Navier-Stokes (URANS) equation. First a rigorous parametric study of choosing right turbulence model for solving URANS (unsteady RNG k-e turbulence model) equation, mesh dependency and optimum time step measurement was carried out using sliding mesh technique in ANSYS Fluent 19.1. Then a series of parametric was conducted to investigate the impact of geometrical parameters on the performance of VAWT. In this study, the geometrical optimization was focused on the impact of blade pre-set pitch and blade mount point offset. The results showed that performance of turbine can increase up to 60% by using appropriate blade offset and pre-set pitch. Another parameter investigated in this research was blade twist. It was revealed that a decrease of up to 65% of amplitude and an increase of up to 45% of performance coefficient could be achieved through the use of properly designed, bend twist vertical blades.