Blade pitch

About: Blade pitch is a research topic. Over the lifetime, 5321 publications have been published within this topic receiving 63134 citations.

Wind power generating device, control method for wind power generating device and computer program

Abstract: PROBLEM TO BE SOLVED: To provide technology enabling to detect a gust of wind beforehand and take countermeasure against a gust of wind such as angle change of a blade without requiring an observation tower. SOLUTION: In a wind power generating device provided with a tower erectly provided on the ground, a nacelle fixed on the tower, and a plurality of blades rotatably fixed on the nacelle via a hub, a Doppler anemometer capable of measuring wind speed in front of the same by sending and receiving sound wave or electromagnetic wave and a blade angle control means controlling angle change of the blade including feathering are provided on the nacelle or the hub, the blade angle control means changes angle of the blade when the Doppler anemometer detects wind speed of a predetermined value or greater. COPYRIGHT: (C)2006,JPO&NCIPI

Initial Results from the Higher Harmonic Control Aeroacoustic Rotor Test (HART) in the German-Dutch Wind Tunnel.

Abstract: In a major cooperative research program within existing US-German and US-French Memoranda of Understanding (MoU's), a comprehensive study was conducted with a 40-percent geometrically and dynamically scaled BO-105 main rotor operated in the open-jet anechoic test section of the German-Dutch Wind Tunnel (DNW). The objectives of the program were to improve the physical understanding and the mathematical modelling of the effects of the higher harmonic blade pitch control technique on blade-vortex interaction (BVI) impulsive noise and vibration reduction. A unique set of acoustic, aerodynamic,dynamic response, performance, and rotor wake data were acquired witha pressure and strain gauge instrumented blade and by application of non-intrusive measurement techniques. This paper is focused on the experimental part of this research program, termed Higher-harmonic- control Aeroacoustic Rotor Test (HART) which was jointly performed by researchers from the US Army Aeroflightdynamics Directorate (AFDD) and NASA Langley, the DNW, and the French and German Aeropace Research Establishments ONERA and DLR. The applied test procedures and obtained key results are presented.

Wind driven power generator with moveable cam

Abstract: A wind driven generator includes a rotor disposed in a cylindrical duct and supported by a frame for rotation in response to wind flowing through the duct. The rotor includes plural circumferentially spaced paralleled rotor blades supported for rotation about a generally horizontal axis. Each blade is supported for pivotal movement to change blade pitch, angle of attack or camber as the rotor rotates. A pitch or camber control motor, self-governing wind vane mechanism, or governing mechanism is operable to move a circular cam to vary blade pitch or camber to control rotor speed. The duct is mounted on a mast having a base supported on a foundation for pivotal movement to face the wind for maximizing air flow through the duct. Electric power generators are connected to opposite ends of the rotor at respective power output or drive shafts.

Performance of twist-coupled blades on variable speed rotors

Abstract: The load mitigation and energy capture characteristics of twist-coupled HAWT blades that are mounted on a variable speed rotor are investigated in this paper. These blades are designed to twist toward feather as they bend with pretwist set to achieve a desirable twist distribution at rated power. For this investigation, the ADAMS-WT software has been modified to include blade models with bending-twist coupling. Using twist-coupled and uncoupled models, the ADAMS software is exercised for steady wind environments to generate C{sub p} curves at a number of operating speeds to compare the efficiencies of the two models. The ADAMS software is also used to generate the response of a twist-coupled variable speed rotor to a spectrum of stochastic wind time series. This spectrum contains time series with two mean wind speeds at two turbulence levels. Power control is achieved by imposing a reactive torque on the low speed shaft proportional to the RPM squared with the coefficient specified so that the rotor operates at peak efficiency in the linear aerodynamic range, and by limiting the maximum RPM to take advantage of the stall controlled nature of the rotor. Fatigue calculations are done for the generated load histories using a range of material exponents that represent materials from welded steel to aluminum to composites, and results are compared with the damage computed for the rotor without twist-coupling. Results indicate that significant reductions in damage are achieved across the spectrum of applied wind loading without any degradation in power production.