Smart Rotor With Trailing Edge Flap Considering Bend–Twist Coupling and Aerodynamic Damping: Modeling and Control

2019 ◽  
Vol 141 (4) ◽  
Author(s):  
Wenguang Zhang ◽  
Ruijie Liu ◽  
Yifeng Wang ◽  
Yuanyuan Wang ◽  
Xu Zhang
Keyword(s):  
Wind Turbine ◽  
Output Power ◽  
Unsteady Aerodynamics ◽  
Coupling Model ◽  
Operating Conditions ◽  
Model Verification ◽  
Control Effect ◽  
Horizontal Axis Wind Turbine ◽  
Trailing Edge ◽  
Aerodynamic Damping

Aerodynamic damping and bend–twist coupling significantly affect the dynamic response of wind turbines. In this paper, unsteady aerodynamics, aerodynamic damping, and bend–twist coupling (twist-towards-feather) are combined to establish a smart rotor model with trailing edge flaps (TEFs) based on a National Renewable Energy Laboratory (NREL) 5 MW reference horizontal-axis wind turbine. The overall idea is to quantitatively evaluate the influence of aerodynamic damping and bend–twist coupling on the smart rotor and to present the control effect of the TEFs under normal wind turbine operating conditions. An aerodynamic model considering the dynamic stall and aerodynamic damping as well as a structural bend–twist coupling model with the influence of gravity and centrifugal force are incorporated into the coupling analysis. The model verification shows that the present model is relatively stable under highly unsteady wind conditions. Then, a robust adaptive tracking (RAT) controller is designed to suppress fluctuations in both the flapwise tip deflection and output power. The simulations show an average reduction of up to 63.86% in the flapwise tip deflection power spectral density (PSD) of blade 1 at the 1P frequency, with an average reduction in the standard deviation of the output power of up to 34.33%.

Comparison of Wind Tunnel Airfoil Performance Data With Wind Turbine Blade Data

1992 ◽  
Vol 114 (2) ◽  
pp. 119-124 ◽  
Author(s):  
C. P. Butterfield ◽  
George Scott ◽  
Walt Musial
Keyword(s):  
Wind Tunnel ◽  
Wind Turbine ◽  
Peak Power ◽  
Unsteady Aerodynamics ◽  
Leading Edge ◽  
Operating Conditions ◽  
Performance Data ◽  
Horizontal Axis Wind Turbine ◽  
Force Coefficients ◽  
Basic Fluid

Horizontal axis wind turbine (HAWT) performance is usually predicted by using wind tunnel airfoil performance data in a blade element momentum theory analysis. This analysis assumes that the rotating blade airfoils will perform as they do in the wind tunnel. However, when stall-regulated HAWT performance is measured in full-scale operation, it is common to find that peak power levels are significantly greater than those predicted. Pitch-controlled rotors experience predictable peak power levels because they do not rely on stall to regulate peak power. This has led to empirical corrections to the stall predictions. Viterna and Corrigan (1981) proposed the most popular version of this correction. But very little insight has been gained into the basic cause of this discrepancy. The National Renewable Energy Laboratory (NREL), funded by the DOE, has conducted the first phase of an experiment which is focused on understanding the basic fluid mechanics of HAWT aerodynamics. Results to date have shown that unsteady aerodynamics exist during all operating conditions and dynamic stall can exist for high yaw angle operation. Stall hysteresis occurs for even small yaw angles and delayed stall is a very persistent reality in all operating conditions. Delayed stall is indicated by a leading edge suction peak which remains attached through angles of attack (AOA) up to 30 degrees. Wind tunnel results show this peak separating from the leading edge at 18 deg AOA. The effect of this anomaly is to raise normal force coefficients and tangent force coefficients for high AOA. Increased tangent forces will directly affect HAWT performance in high wind speed operation. This report describes pressure distribution data resulting from both wind tunnel and HAWT tests. A method of bins is used to average the HAWT data which is compared to the wind tunnel data. The analysis technique and the test set-up for each test are described.

scholarly journals Perancangan Prototipe Turbin Angin Sumbu Horizontal Skala Laboratorium Dengan Inverter

2021 ◽  
Vol 1 (1) ◽  
pp. 24-29
Author(s):  
Najma Safienatin Najah ◽  
Arief Muliawan ◽  
Febria Anita
Keyword(s):  
Wind Turbine ◽  
Output Power ◽  
Design Research ◽  
Horizontal Axis ◽  
Horizontal Axis Wind Turbine ◽  
Research Results ◽  
Turn On ◽  
Generator Voltage ◽  
Turbine Design ◽  
Generator Currents

A horizontal axis wind turbine design research has been carried out using an inverter. This study aims to generate the output power generated by the generator through an inverter. So that the use of an inverter can turn on the 10 watt lamp. From the research results obtained turbine rotation varied between 1357 rpm to 2415 rpm producing a generator voltage of 3.05 volts to 4.61 volts and generator currents 32mA up to 49 mA. The inverter produces a voltage of 16.57 volts up to 20.46 volts and an inverter current of 0.60 amperes up to 0.48 amperes. The greater the rotation of the wind turbine turbine, the greater the generator voltage generated and so is the voltage of the inverter. While the current will increase as the turbine rotation increases and the inverse of the inverter current will decrease as the turbine rotation increases.

scholarly journals Modeling and simulation of forces applied to the horizontal axis wind turbine rotors by the vortex method coupled with the method of the blade element

2021 ◽  
Vol 12 (1) ◽  
pp. 413
Author(s):  
Ibtissem Barkat ◽  
Abdelouahab Benretem ◽  
Fawaz Massouh ◽  
Issam Meghlaoui ◽  
Ahlem Chebel
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Wind Farms ◽  
Vortex Method ◽  
Operating Conditions ◽  
Horizontal Axis ◽  
Rotor Blades ◽  
Good Representation ◽  
Horizontal Axis Wind Turbine ◽  
Blade Element

This article aims to study the forces applied to the rotors of horizontal axis wind turbines. The aerodynamics of a turbine are controlled by the flow around the rotor, or estimate of air charges on the rotor blades under various operating conditions and their relation to the structural dynamics of the rotor are critical for design. One of the major challenges in wind turbine aerodynamics is to predict the forces on the blade as various methods, including blade element moment theory (BEM), the approach that is naturally adapted to the simulation of the aerodynamics of wind turbines and the dynamic and models (CFD) that describes with fidelity the flow around the rotor. In our article we proposed a modeling method and a simulation of the forces applied to the horizontal axis wind rotors turbines using the application of the blade elements method to model the rotor and the vortex method of free wake modeling in order to develop a rotor model, which can be used to study wind farms. This model is intended to speed up the calculation, guaranteeing a good representation of the aerodynamic loads exerted by the wind.

Analysis of Unsteady Flows Past Horizontal Axis Wind Turbine Airfoils Based on Harmonic Balance Compressible Navier-Stokes Equations With Low-Speed Preconditioning

2011 ◽  
Author(s):  
M. Sergio Campobasso ◽  
Mohammad H. Baba-Ahmadi
Keyword(s):  
Wind Turbine ◽  
Time Domain ◽  
Harmonic Balance ◽  
Stokes Equations ◽  
Unsteady Aerodynamics ◽  
Horizontal Axis ◽  
Navier Stokes ◽  
Horizontal Axis Wind Turbine ◽  
Low Speed ◽  
Computational Performance

This paper presents the numerical models underlying the implementation of a novel harmonic balance compressible Navier-Stokes solver with low-speed preconditioning for wind turbine unsteady aerodynamics. The numerical integration of the harmonic balance equations is based on a multigrid iteration, and, for the first time, a numerical instability associated with the use of such an explicit approach in this context is discussed and resolved. The harmonic balance solver with low-speed preconditioning is well suited for the analyses of several unsteady periodic low-speed flows, such as those encountered in horizontal axis wind turbines. The computational performance and the accuracy of the technology being developed are assessed by computing the flow field past two sections of a wind turbine blade in yawed wind with both the time- and frequency-domain solvers. Results highlight that the harmonic balance solver can compute these periodic flows more than 10 times faster than its time-domain counterpart, and with an accuracy comparable to that of the time-domain solver.

Navier-Stokes and Comprehensive Analysis Performance Predictions of the NREL Phase VI Experiment

2003 ◽  
Author(s):  
Earl P. N. Duque ◽  
Michael D. Burklund ◽  
Wayne Johnson
Keyword(s):  
Experimental Data ◽  
Wind Turbine ◽  
Turbine Rotor ◽  
Operating Conditions ◽  
Navier Stokes ◽  
Horizontal Axis Wind Turbine ◽  
Performance Predictions ◽  
Nasa Ames Research ◽  
Nrel Phase Vi ◽  
Wind Turbine Rotor

A vortex lattice code, CAMRAD II, and a Reynolds-Averaged Navier-Stoke code, OVERFLOW-D2, were used to predict the aerodynamic performance of a two-bladed horizontal axis wind turbine. All computations were compared with experimental data that was collected at the NASA Ames Research Center 80-by 120-Foot Wind Tunnel. Computations were performed for both axial as well as yawed operating conditions. Various stall delay models and dynamics stall models were used by the CAMRAD II code. Comparisons between the experimental data and computed aerodynamic loads show that the OVERFLOW-D2 code can accurately predict the power and spanwise loading of a wind turbine rotor.

scholarly journals Efficient contribution of partially tip cascaded horizontal-axis wind turbine

2019 ◽  
Vol 11 (11) ◽  
pp. 168781401989211
Author(s):  
Deyaa Nabil Elshebiny ◽  
Ali AbdelFattah Hashem ◽  
Farouk Mohammed Owis
Keyword(s):  
Wind Turbine ◽  
Aerodynamic Performance ◽  
Operating Conditions ◽  
Horizontal Axis ◽  
National Renewable Energy Laboratory ◽  
Horizontal Axis Wind Turbine ◽  
Ansys Fluent ◽  
Knowing That ◽  
Turbine Performance ◽  
Blade Tip

This article introduces novel blade tip geometric modification to improve the aerodynamic performance of horizontal-axis wind turbine by adding auxiliary cascading blades toward the tip region. This study focuses on the new turbine shape and how it enhances the turbine performance in comparison with the classical turbine. This study is performed numerically for National Renewable Energy Laboratory Phase II (non-optimized wind turbine) taking into consideration the effect of adding different cascade configurations on the turbine performance using ANSYS FLUENT program. The analysis of single-auxiliary and double-auxiliary cascade blades has shown an impact on increasing the turbine power of 28% and 76%, respectively, at 72 r/min and 12.85 m/s of wind speed. Knowing that the performance of cascaded wind turbine depends on the geometry, solidity and operating conditions of the original blade; therefore, these results are not authorized for other cases.

Numerical Studies of the Effects of Active and Passive Circulation Enhancement Concepts on Wind Turbine Performance

2006 ◽  
Vol 128 (4) ◽  
pp. 432-444 ◽  
Author(s):  
Chanin Tongchitpakdee ◽  
Sarun Benjanirat ◽  
Lakshmi N. Sankar
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Flow Analysis ◽  
Three Dimensional ◽  
Turbine Rotor ◽  
Horizontal Axis Wind Turbine ◽  
Trailing Edge ◽  
Low Wind Speed ◽  
Gurney Flap ◽  
Coanda Jet

The aerodynamic performance of a wind turbine rotor equipped with circulation enhancement technology (trailing-edge blowing or Gurney flaps) is investigated using a three-dimensional unsteady viscous flow analysis. The National Renewable Energy Laboratory Phase VI horizontal axis wind turbine is chosen as the baseline configuration. Experimental data for the baseline case is used to validate the flow solver, prior to its use in exploring these concepts. Calculations have been performed for axial and yawed flow at several wind conditions. Results presented include radial distribution of the normal and tangential forces, shaft torque, root flap moment, and surface pressure distributions at selected radial locations. At low wind speed (7m∕s) where the flow is fully attached, it is shown that a Coanda jet at the trailing edge of the rotor blade is effective at increasing circulation resulting in an increase of lift and the chordwise thrust force. This leads to an increased amount of net power generation compared to the baseline configuration for moderate blowing coefficients (Cμ⩽0.075). A passive Gurney flap was found to increase the bound circulation and produce increased power in a manner similar to Coanda jet. At high wind speed (15m∕s) where the flow is separated, both the Coanda jet and Gurney flap become ineffective. The effects of these two concepts on the root bending moments have also been studied.

Influence of microcylinders with different vibration laws on the flow control effect of a horizontal axis wind turbine

Wind Energy ◽  
2019 ◽  
Vol 22 (12) ◽  
pp. 1800-1824
Author(s):  
Ying Wang ◽  
Gaohui Li ◽  
Dahai Luo ◽  
Diangui Huang
Keyword(s):  
Flow Control ◽  
Wind Turbine ◽  
Horizontal Axis ◽  
Control Effect ◽  
Horizontal Axis Wind Turbine

Modeling of Rain Drop Erosion in a Multi-MW Wind Turbine

2015 ◽  
Author(s):  
Alessandro Corsini ◽  
Alessio Castorrini ◽  
Enrico Morei ◽  
Franco Rispoli ◽  
Fabrizio Sciulli ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Stokes Equations ◽  
Turbine Blades ◽  
Operating Conditions ◽  
Design Stage ◽  
Base Line ◽  
Horizontal Axis Wind Turbine ◽  
Relevant Effect ◽  
The Impact ◽  
Rain Erosion

The actual strategy in offshore wind energy development is oriented to the progressive increase of the turbine diameter as well as the per unit power. Among many pioneering technological and aerodynamic issues linked to this design trend, the wind velocity at the blade tip region reaches very high values in normal operating conditions (typically between 90 to 110 m/s). In this range of velocity, the rain erosion phenomenon can have a relevant effect on the overall turbine performance in terms of power and energy production (up to 20% loss in case of deeply eroded leading edge). Therefore, as a customary approach erosion related issues are accounted for in the scheduling of the wind turbine maintenance. When offshore, on the other hand, the criticalities inherent to the cost of maintenance and operation monitoring suggest the rain erosion concerns to be tackled at the turbine design stage. In so doing, the use of computational tools to study the erosion phenomenon of wind turbines under severe meteorological conditions could define the base-line approach in the wind turbine blades design and verification. In this work, the authors present a report on numerical prediction of erosion on a 6 MW HAWT (horizontal axis wind turbine). Two different blade geometries of different aerodynamic loading, have been studied in a view to explore their sensitivity to rain erosion. The fully 3D simulations are carried out using an Euler-Lagrangian approach. Flow field simulations are carried out with the open-source code OpenFOAM, based on a finite volume approach, using Multiple Reference Frame methodology. Reynolds Averaged Navier-Stokes equations for incompressible steady flow were solved with a k-ε turbulence. An in-house code (P-Track) is used to compute the rain drops transport and dispersion, adopting the Particle Cloud Tracking approach (PCT), already validated on large industrial turbomachinery. At the impact on blade, erosion is modelled accounting for the main quantities affecting the phenomenon, which are impact velocity and material properties of the target surface. Results provide the regions of the two blades more sensitive to erosion, and the effect of the blade geometry on erosion attitude.

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