CONCENTRATION AND AUGMENTATION BY CHANDRAVATI (0806454016) APARAJITA SHANKAR(0806454011)

THANK U

The present invention describes a principle of operation that can be appliedto a large variety of new wind turbines designs. As a function of the choices in design, this new generation of a wind turbine apparatus improves or remedies each of the above- mentioned problems associated with traditional wind turbines The basic concept is the funnelling of wind in a conduit to concentring it. The flux of compressed air is thereby directed to interact with the most efficient surface of a wind turbine propeller blade.

The turbine can thus be designed with the goal of benefiting from the weakest winds or, contrarily,benefiting from the strongest winds. Since the wind turbine is housed within the apparatus, the resulting noise caused by aerodynamic motions can be almost completely attenuated. Furthermore, an enclosed wind turbine conceals the visible movement of the propellers and protects flying wildlife

AERODINAMICS Aerodynamics is a branch of dynamics concerned with studying the motion of air, particularly when it interacts with a solid object. Aerodynamics is a subfield of fluid dynamics and gas dynamics, with much theory shared between them. Aerodynamics is often used synonymously with gas dynamics, with the difference being that gas dynamics applies to all gases.

Induced Flow Production This figure illustrates how still air is changed to a column of descending air by rotor blade action

Relative Wind Relative wind is defined as the airflow relative to an airfoil Relative wind is created by movement of an airfoil through the air

Resultant Relative Wind Airflow from rotation, modified by induced flow, produces the Resultant Relative Wind Angle of attack is reduced by induced flow, causing the airfoil to produce less lift

Angle of Attack Angle of Attack (AOA) (4) is the angle between the airfoil chord line and its direction of motion relative to the air (the Resultant Relative Wind)

Angle of Incidence Angle of Incidence (or AOI) is the angle between the blade chord line and the plane of rotation of the rotor system.

Total Aerodynamic Force A Total Aerodynamic Force (3) is generated when a stream of air flows over and under an airfoil that is moving through the air

Total Aerodynamic Force Total aerodynamic force may be divided into two components called lift and drag Lift acts on the airfoil in a direction perpendicular to the relative wind Drag acts on the airfoil in a direction parallel to the relative wind and is the force that opposes the motion of the airfoil through the air

AUGMENTATION Diffuser Augmented Wind Turbines (DAWTs) are one of many concepts to have been proposed to reduce the cost of renewable energy. As the most commercially viable, they have been the focus of numerous theoretical, computational, and experimental investigations. Although intimated in these studies to be able to augment the power output of a wind turbine, the extent of this power increase, or augmentation, the factors influencing DAWT performance, the optimal geometric form and their economical benefit remained unanswered.

To translate the available augmentation into shaft power a modified blade element method has been developed using an empirically-derived axial velocity equation. The resulting blade designs whose efficiencies reached 77%, twice those of Grumman, highlight the accuracy of the modified blade element method in calculating the flow conditions at the blade-plane of the multi-slotted DAWT. It was also noted that the rotor efficiencies remain below 'best practice' and therefore offer the potential for further increases in shaft augmentation