Turbine blades, systems and methods

Abstract

A blade for use in a wind turbine comprises a pressure side and suction side meeting at a trailing edge and leading edge, the pressure side having a pressure side surface and the suction side having a suction side surface, the pressure side surface and suction side surface for providing lift to the turbine blade upon the flow of air from the leading edge to the trailing edge and over the pressure side and suction side surfaces, the pressure side and suction side extending from a root portion to a tip portion of the turbine blade. In some situations, the root portion is non-aerodynamic. The aerodynamics of such a blade is improved with the aid of pneumatic blowing through one or more blown passages for providing pressurized air (or other fluid) to a suction side and/or pressure side of the blade.

Description

CROSS-REFERENCE[0001]This application claims priority to U.S. Provisional Patent Application Ser. No. 61 / 442,761, filed on Feb. 14, 2011, and U.S. Provisional Patent Application Ser. No. 61 / 453,941, filed on Mar. 17, 2011, which are entirely incorporated herein by reference.STATEMENT AS TO FEDERALLY SPONSORED RESEARCH[0002]This invention was made with Government support under DE-00000022 awarded by the United States Department of Energy. The Government has certain rights in the invention.BACKGROUND OF THE INVENTION[0003]An airfoil (or aerofoil) is the cross-sectional shape of a wing or blade or sail. An airfoil-shaped body that is moved through a fluid may produce an aerodynamic force. The component of this force perpendicular to the direction of motion may be called lift. The component of this force parallel to the direction of motion may be called drag.[0004]A turbine is a rotary engine that may extract energy from a fluid flow and convert it into work. Turbines may have one or mo...

AI Technical Summary

Benefits of technology

[0006]In embodiments, blades (e.g., turbine blades) are provided that are mechanically simple, highly efficient, structurally strong, cost effective, and controllable for effectively extracting energy from ambient winds. In some cases, this is accomplished by augmenting or controlling the aerodynamics of turbine blades with the use of pneumatic blowing out of the blades, which may generate forces and extract energy even at substantially low wind velocities. Concurrently, blown blade airfoils are structurally strong and the lift, drag and torque produced by such blades may be made relatively independent of the local relative wind angle, thus eliminating the complex problems of blade pitch and pitch control mechanisms. Devices provided herein may achieve, among other things, substantially high lift on specialized blown blades; drag increase (braking) or reduction (efficiency) as required; control of the aerodynamic moments on these blades; prevention of flow separation on these blades (except when flow separation would be desirable, such as for braking); and the ability to perform all of these capabilities without any physical change in the local blade angle of attack to the oncoming flow. These capabilities allow energy extraction from the ambient wind over a wider range of wind speeds and local wind stream angles of attack on the blades. This will be achieved, for example, with one blowing slot or a plurality of tangential blowing slots located on either end of the individual blade airfoil (leading edge or training edge), and on either side of the airfoil (pressure or suction side). In addition to very high lift and reduced drag, thus high aerodynamic lift / drag ratios and efficiency, these characteristics may be varied by the adjustment of only the blade blowing rates or blowing pressures at these slots.

Problems solved by technology

The root portion may be operating in a region of ineffective aerodynamic flow, such as a region of flow separation.

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