Author: Charles P. ButterfieldPublisher:
ISBN:
Category : Aerodynamic load
Languages : en
Pages : 36
Book Description
Aerodynamic Pressure and Flow-visualization Measurement from a Rotating Wind Turbine Blade
Author: Charles P. ButterfieldPublisher:
ISBN:
Category : Aerodynamic load
Languages : en
Pages : 36
Book Description
Aerodynamic Pressure and Flow-visualization Measurement from a Rotating Wind Turbine Blade
Author: Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Aerodynamic, load, flow-visualization, and inflow measurements have been made on a 10-m, three-bladed, downwind, horizontal-axis wind turbine (HAWT). A video camera mounted on the rotor was used to record nighttime and daytime video images of tufts attached to the low-pressure side of a constant-chord, zero-twist blade. Load measurements were made using strain gages mounted at every 10% of the blade's span. Pressure measurements were made at 80% of the blade's span. Pressure taps were located at 32 chordwise positions, revealing pressure distributions comparable with wind tunnel data. Inflow was measured using a vertical-plane array of eight propvane and five triaxial (U-V-W) prop-type anemometers located 10 m upwind in the predominant wind direction. One objective of this comprehensive research program was to study the effects of blade rotation on aerodynamic behavior below, near, and beyond stall. To this end, flow patterns are presented here that reveal the dynamic and steady behavior of flow conditions on the blade. Pressure distributions are compared to flow patterns and two-dimensional wind tunnel data. Separation boundary locations are shown that change as a function of spanwise location, pitch angle, and wind speed. 6 refs., 23 figs., 1 tab.
Aerodynamic Testing of a Rotating Wind Turbine Blade
Author: C. P. ButterfieldPublisher:
ISBN:
Category : Pressure
Languages : en
Pages : 0
Book Description
Aerodynamic, load, flow-visualization, and inflow measurements were taken on a downwind horizontal-axis wind turbine (HAWT). A video camera mounted on the rotor recorded video images of tufts attached to the low-pressure side of the blade. Strain gages, mounted every 10% of the blade's span, provided load and pressure measurements. Pressure taps at 32 chordwise positions recorded pressuredistributions. Wind inflow was measured via a vertical-plane array of anemometers located 10 m upwind. The objectives of the test were to address whether airfoil pressure distributions measured on a rotating blade differed from those measured in the wind tunnel, if radial flow near or in the boundary layer of the airfoil affected pressure distributions, if dynamic stall could result in increaseddynamic loads, and if the location of the separation boundary measured on the rotating blade agreed with that measured in two-dimensional flow in the wind tunnel.
Quantitative Measurement Techniques for Wind Turbine Blade Aerodynamic Performance
Author: Tyler GallantPublisher:
ISBN:
Category : Aerodynamics
Languages : en
Pages : 175
Book Description
The installed capacity of wind turbines has been growing rapidly in recent years, creating an increased need for accurate measurements and models of wind turbine performance to further their development. There is a need in the literature for experimental data to validate theoretical models and guide turbine blade design. Two related projects were completed to develop measurement techniques and provide such data: the use of a five-hole probe and in-blade data acquisition system to measure the wind turbine blade angle of attack, and the use of tuft flow visualization and a digital image processing algorithm to quantitatively assess the flow direction and behaviour of a wind turbine blade. Experiments were completed at the University of Waterloo Wind Generation Research Facility using a 3.3 m diameter test turbine. Wind speed, rotational speed, shaft torque and angular position were controlled or monitored throughout all experiments. A 3D printed test blade was equipped with a five-hole pressure probe and data acquisition system to measure the flow angles at various radial locations. For tuft flow visualization testing, a separate rotor consisting of three aerodynamic blades was installed, and tufts and a camera were mounted to the surface of one of the blades. Extensive software was developed for controlling instruments and collecting experimental data. The angle of attack and span-wise flow angles were successfully measured as a function of the tip speed ratio, yaw-offset position, radial location and azimuthal position. Variations in the angle of attack with these variables were consistent with wind turbine aerodynamics theory, and results were in close agreement with results calculated using two separate models from the literature. Angle of attack values typically ranged from 7° to 25° throughout the tests, with fluctuations as high as 7°when the wind turbine was yawed. Uncertainty values in the measurements were typically found to be within ±0.2°, which shows great potential for the method. Tuft flow visualization measurements were processed by logging the orientation of each individual tuft, calculating their average orientations and interpolating to develop a contour map of flow direction over the wind turbine blade as a function of tip speed ratio, yaw-position and azimuthal position. Throughout testing, the fraction of tufts indicating stall ranged from 25% to as high as 60% as the tip speed ratio was decreased. Contour maps showed that separation typically formed first on the trailing edge of the blade near the root, and expanded towards the leading edge and tip. This pattern is in agreement with trends found for similar blades in the literature.
Scientific and Technical Aerospace Reports
Author: Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 456
Book Description
Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
Wind Turbine Aerodynamics
Author: Wen Zhong ShenPublisher: MDPI
ISBN: 3039215248
Category : Technology & Engineering
Languages : en
Pages : 410
Book Description
Wind turbine aerodynamics is one of the central subjects of wind turbine technology. To reduce the levelized cost of energy (LCOE), the size of a single wind turbine has been increased to 12 MW at present, with further increases expected in the near future. Big wind turbines and their associated wind farms have many advantages but also challenges. The typical effects are mainly related to the increase in Reynolds number and blade flexibility. This Special Issue is a collection of 21 important research works addressing the aerodynamic challenges appearing in such developments. The 21 research papers cover a wide range of problems related to wind turbine aerodynamics, which includes atmospheric turbulent flow modeling, wind turbine flow modeling, wind turbine design, wind turbine control, wind farm flow modeling in complex terrain, wind turbine noise modeling, vertical axis wind turbine, and offshore wind energy. Readers from all over the globe are expected to greatly benefit from this Special Issue collection regarding their own work and the goal of enabling the technological development of new environmentally friendly and cost-effective wind energy systems in order to reach the target of 100% energy use from renewable sources, worldwide, by 2050
Aerodynamic Pressure Measurements on a Rotating Wind Turbine Blade
Author: Charles P. ButterfieldPublisher:
ISBN:
Category : Pressure
Languages : en
Pages : 10
Book Description
Wind turbine generators commonly operate in either a fixed-pitch or variable-pitch mode. In variable-pitch mode the angle of the blade is changed as the wind speed varies to maintain near optimum airfoil angle of attack and to regulate peak power. The more common fixed-pitch rotors do not change pitch angle to regulate peak power. Instead the blade is allowed to stall aerodynamically. This approach results in rapid relief of loads caused by gusts and is more reliable and cost effective. However, the designer must accurately understand the rotating-blade stall; behavior of the airfoil in order to predict turbine loads. To understand such stall behavior a test program that uses specially designed instrumentation has been conducted by the Solar Energy Research Institute (SERI). A microprocessor-controlled measurement system has been designed and built to make accurate measurements of low pressures on a rotating wind turbine blade.
Three-dimensional Airfoil Performance Measurements on a Rotating Wing
Author: Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
The objective of this comprehensive research program was to study the effects of horizontal-axis wind turbine (HAWT) blade rotation on aerodynamic behavior below, near, and beyond stall. This paper describes the flow angle sensor used to measure angle of attack (AOA) and how the sensor was calibrated, and it gives results of pressure integrations on the blade. Aerodynamic, load, flow-visualization, and inflow measurements were made on a 10-m, three-bladed, downwind HAWT. A video camera was mounted on the rotor to record video images of tufts attached to the low-pressure side of a constant-chord, zero-twist blade. Load measurements were made using strain gages mounted every 10% of the blade's span. Pressure taps were located at 32 chordwise positions and revealed pressure distributions comparable with wind tunnel data. Inflow was measured using a vertical-plane array of eight propvane and five triaxial (U-V-W) prop-type anemometers located 10 m upwind in the predominant wind direction. Results show evidence of stall hysteresis and unsteadiness at high AOA. Correlations with analytical predictions and wind tunnel tests show good agreement at low AOA and poor agreement at high AOA. 7 refs., 12 figs.
Aerodynamic Pressure Measurements on a Rotating Wind Turbine Blade
Author: Publisher:
ISBN:
Category : Pressure
Languages : en
Pages : 0
Book Description
Wind turbine generators commonly operate in either a fixed-pitch or variable-pitch mode. In variable-pitch mode the angle of the blade is changed as the wind speed varies to maintain near optimum airfoil angle of attack and to regulate peak power. The more common fixed-pitch rotors do not change pitch angle to regulate peak power. Instead the blade is allowed to stall aerodynamically. This approach results in rapid relief of loads caused by gusts and is more reliable and cost effective. However, the designer must accurately understand the rotating-blade stall; behavior of the airfoil in order to predict turbine loads. To understand such stall behavior a test program that uses specially designed instrumentation has been conducted by the Solar Energy Research Institute (SERI). A microprocessor-controlled measurement system has been designed and built to make accurate measurements of low pressures on a rotating wind turbine blade.
Author: