STATE OF THE ART OF SMALL WIND ENERGY ANALYSING DIFFERENT CONTROLS

There are two wind turbine topologies according to the axis of rotation: horizontal axis, "Horizontal Axis Wind Turbines" (HAWT) and vertical axis, "Vertical Axis Wind Turbines" (VAWT) [2]. HAWT turbines are used for high power generation as they have a higher energy conversion efficiency [2]. However, VAWTs are used in mini wind applications because they do not need to be oriented to the prevailing wind and have lower installation cost.

Numerical and Experimental Investigations on a Bio-Inspired Design of Darrieus Vertical Axis Wind Turbine Blades With Leading Edge Tubercles

Various improvements can be made to Darrieus vertical axis wind turbines (VAWT) for maximum performance in an urban environment. One such improvement is the inclusion of bio-inspired leading-edge tubercles to increase the aerodynamic performance. These structures, found on the flippers of humpback whales, are believed to aid the mammal in quick maneuvering. The objective of the chapter is to investigate and compare the performance of a Darrieus type VAWT with the inclusion of leading edge tubercles. The performance of the turbine with leading-edge tubercles on the blades is compared with the turbine with normal blade, computationally (with computational fluid dynamics using transition SST turbulence model) and experimentally. The focus lies on building an experimental setup to compare the performance of leading-edge tubercles with the baseline turbine.

Design and Performance Evaluation of Low-Speed Vertical Axis Wind Turbines with Wind Boosters using CFD Analysis

The use of wind based energy is quickly expanding over the planet. The goal of this study is to use computational methods of fluid dynamics to develop a novel model of VAWT including Windbooster for various rotor blades like two, three, and four blades in order to enhance effectiveness. CAD modelling approaches of vertical axis wind turbines including and excluding booster are created. Including all vertical axis wind turbine blade designs including and excluding booster, torque, power, and Coefficient of performance are compared.The performance of three blades on the basis of mechanical properties includingi wind amplifier is 29.9% greater than two blades using wind amplifier, and four blades using wind amplifier is 21.5 percent greater than three blades using wind amplifier, according to the findings. Because the mechanical energy created by a four-blade wind booster wasn't as great as it is including three blades, VAWT employing three-blade wind booster seems to be more effective than VAWT with a two- or four-blade wind booster. For improved mechanical durability, VAWT with three-blade wind amplifier is recommended.

Computational Analysis of VAWT Micro Wind Farm for Urban Rooftops

Technological advancements have improved energy efficiency and increased energy requirements requiring improved energy density solutions to optimally utilize the existing landscape. The renewable energy density of urban rooftops can be increased by introducing micro wind farms consisting of vertical axis wind turbines (VAWT). VAWTs do not require directed flow thus a feasible choice. In this paper, the preliminary study for parametric design of horizontal distance between two identical Savonius wind turbines is presented. Three different simulations were performed to reveal important insights about this problem with an inlet velocity of 2 m/s. The results suggest 3D analysis for accurate insights.

Vertical axis wind turbine operation in icing conditions: A review study

Vertical Axis Wind Turbine (VAWT) can be a promising solution for electricity production in remote ice prone territories of high north, where good wind resources are available, but icing is a challenge that can affect its optimum operation. A lot of research has been made to study the icing effects on the conventional horizontal axis wind turbines, but the literature about vertical axis wind turbines operating in icing conditions is still scarce, despite the importance of this topic. This paper presents a review study about existing knowledge of VAWT operation in icing condition. Focus has been made in better understanding of ice accretion physics along VAWT blades and methods to detect and mitigate icing effects.

Aeroacoustics behavioral study of Savonius wind turbine

Vertical Axis Wind Turbines (VAWTs) are appropriate for use in populated areas. If VAWTs were installed at residential areas, the generated aerodynamic noise can be harmful in a way or another. Therefore, in the present study, the aero-acoustics of the conventional Savonius Wind turbine was investigated using Computational Fluid Dynamics (CFD). Both the Unsteady Reynolds-averaged Navier-Stokes (URANS) equations and impermeable Ffowcs Wiliams and Hawkings (FW-H) equation were simultaneously solved. The effect of speed ratio was also studied. The results indicate that; the pressure is inversely proportional to the speed ratio. Additionally, the velocity has been increased due to the increase of the tip speed ratio. Finally, it has improved that for the majority of receivers, the overall sound level increases with increasing speed ratio.

Blades Interaction and Non-Stationarity of Flow in Vertical-Axial Wind Turbines

Until recently, horizontal-axial wind turbines with blades having a wing profile occupied a predominant position in the world wind energy market. But currently, vertical-axial wind units are of increasing interest and this is understandable from the point of view of their important features as: no requirements for the orientation of the wind turbine to the wind, the possibility of placing electrical and other equipment on the ground, no requirements for changes of blade chord installation angle along its length. The article discusses the aerodynamics of the vertical-axis wind turbines: the range of changes of angles of incoming flow attack on the blade, the dynamics of changes in the magnitude of the absolute speed of flow of the blade on a circular trajectory of its movement depending on the turbine rapidity, and also obtained in experiments interaction effect of the blades in the rotor. The experiments were carried out on wind turbines with original blades (basic version), which were designed to eliminate the shortcomings of low-speed rotors Savonius (low coefficient of use of wind energy) and high-speed rotors Darrieus (lack of self-start).