Horizontal axis

Turbulence

Engineering

Aerospace engineering

Turbine blade

Geotechnical engineering

Materials science

Marine engineering

Reynolds number

Vertical axis wind turbine

Tip-speed ratio

Vertical axis

Wells turbine

Geology

Porosity

Mechanical engineering

Thermodynamics

Physics

Torque

Flow (mathematics)

Wake

Environmental science

Composite material

Turbine

Wind power

Structural engineering

Engineering drawing

Meteorology

Mechanics

Rotational speed

Electrical engineering

Energy Conversion and Management

The present study proposed a novel porous deflector in front of the Savonius wind turbine to improve the performance. This new deflector was specifically proposed to minimize the severe effects of the complex wake zone created behind the conventional solid deflector that had not been investigated yet. This caused a deeper investigation into the effect of severe negative effects on the turbine performance to achieve an appropriate design configuration. Therefore, different configuration parameters were taken into account during the numerical process. The unsteady Reynolds-averaged Navier-Stokes equation in conjunction with the SST k-ω turbulence model was numerically solved. Comprehensive comparisons of torque, power, and flow structures between deflector configurations and the standard Savonius turbine were performed to illustrate the mechanism of how the porous deflector improved the turbine performance. Using a porous deflector caused the wind flow passed through the porous zone resulted in a breakdown of the wake zone behind the deflector. Thereby, the flow structures became more regular with fewer fluctuations. The results demonstrated that there is an appropriate porosity value to obtain the highest torque and power coefficients. The maximum value of the power coefficient increased by approximately 10% using the favorable configuration of porous deflector at a tip speed ratio of 1. The notable observation was that the appropriate configuration increased the static torque coefficient approximately 2 times in the rotation angles between 0° and 30° which proved the self-starting ability besides power coefficient enhancement.

Performance improvement of a Savonius vertical axis wind turbine using a porous deflector