scholarly journals Moving Accelerometers to the Tip: Monitoring of Wind Turbine Blade Bending Using 3D Accelerometers and Model-Based Bending Shapes

Sensors ◽  
2020 ◽  
Vol 20 (18) ◽  
pp. 5337
Author(s):  
Theresa Loss ◽  
Alexander Bergmann
Keyword(s):  
Wind Turbine ◽  
Turbine Blades ◽  
Rotation Frequency ◽  
Real Data ◽  
Maximum Energy ◽  
Wind Turbine Blades ◽  
Energy Capture ◽  
Model Based ◽  
Blade Tip ◽  
Wind Profiles

Increasing the length of wind turbine blades for maximum energy capture leads to larger loads and forces acting on the blades. In particular, alternate bending due to gravity or nonuniform wind profiles leads to increased loads and imminent fatigue. Therefore, blade monitoring in operation is needed to optimise turbine settings and, consequently, to reduce alternate bending. In our approach, an acceleration model was used to analyse periodically occurring deviations from uniform bending. By using hierarchical clustering, significant bending patterns could be extracted and patterns were analysed with regard to reference data. In a simulation of alternate bending effects, various effects were successfully represented by different bending patterns. A real data experiment with accelerometers mounted at the blade tip of turbine blades demonstrated a clear relation between the rotation frequency and the resulting bending patterns. Additionally, the markedness of bending shapes could be used to assess the amount of alternate bending of the blade in both simulations and experiment.s The results demonstrate that model-based bending shapes provide a strong indication for alternate bending and, consequently, can be used to optimise turbine settings.

Parametric Stiffness in Large-Scale Wind-Turbine Blades and the Effects on Resonance and Speed Locking

2020 ◽  
Author(s):  
Ayse Sapmaz ◽  
Brian F. Feeny
Keyword(s):  
Wind Turbine ◽  
Large Scale ◽  
Turbine Blades ◽  
Relative Strength ◽  
Wind Turbine Blades ◽  
Fixed Position ◽  
Horizontal Axis Wind Turbine ◽  
Parametric Effect ◽  
Parametric Effects ◽  
Blade Tip

Abstract This paper is on parametric effect in large scale horizontal-axis wind-turbine blades and speed locking phenomenon for a simplified model of the in-plane blade-hub dynamics. The relative strength of the parametric stiffness is evaluated for actual and scaled-length blades. Fixed-position natural frequencies are found at different rotation angles to show the significance of the gravity’s parametric effect. The ratio of the parametric and elastic modal stiffness is then estimated for the scaled versions of the NREL’s blades for four models to present the relation between the blade size and the parametric effects. The parametric effect on blade tip placements are investigated for superharmonic resonances at orders two and three for blades of various lengths. An analysis of speed-locking is presented, and interpreted for the various blades.

Numerical Analysis of Aeroelastic Responses of Wind Turbine Under Uniform Inflow

2020 ◽  
Author(s):  
Yang Huang ◽  
Decheng Wan
Keyword(s):  
Wind Turbine ◽  
Structural Model ◽  
Turbine Blades ◽  
Structural Deformation ◽  
Wind Turbine Blades ◽  
Wake Field ◽  
Wind Speeds ◽  
Inflow Condition ◽  
Blade Tip ◽  
Aeroelastic Simulations

Abstract With wind turbine blades becoming longer and slender, the influence of structural deformation on the aerodynamic performance of wind turbine cannot be ignored. In the present work, the actuator line technique that simplifies the wind turbine blades into virtual actual lines is utilized to simulate the aerodynamic responses of wind turbine and capture downstream wake characteristics. Moreover, the structural model based on a two-node, four degree-of-freedom (DOF) beam element is adopted for the deformation calculation of the wind turbine blades. By combing the actuator line technique and linear finite element theory, the aeroelastic simulations for the wind turbine blades can be achieved. The aeroelastic responses of NREL-5MW wind turbine under uniform wind inflow condition with different wind speeds are investigated. The aerodynamic loads, turbine wake field, blade tip deformations and blade root bending moments are analyzed to explore the influence of blade structural responses on the performance of the wind turbine. It is found that the power output of the wind turbine decreases when the blade deformation is taken into account. Significant asymmetrical phenomenon of the wake velocity is captured due to the deformation of the wind turbine blades.

scholarly journals Vibration-Based Fingerprint Algorithm for Structural Health Monitoring of Wind Turbine Blades

2021 ◽  
Vol 11 (9) ◽  
pp. 4294
Author(s):  
Theresa Loss ◽  
Alexander Bergmann
Keyword(s):  
Wind Turbine ◽  
Turbine Blades ◽  
Radial Distance ◽  
Study Data ◽  
Detailed Knowledge ◽  
Wind Turbine Blades ◽  
Energy Capture ◽  
Structural Health ◽  
Vibrational Characteristics ◽  
Fingerprint Algorithm

Monitoring the structural health of wind turbine blades is essential to increase energy capture and operational safety of turbines, and therewith enhance competitiveness of wind energy. With the current trends of designing blades ever longer, detailed knowledge of the vibrational characteristics at any point along the blade is desirable. In our approach, we monitor vibrations during operation of the turbine by wirelessly measuring accelerations on the outside of the blades. We propose an algorithm to extract so-called vibration-based fingerprints from those measurements, i.e., dominant vibrations such as eigenfrequencies and narrow-band noise. These fingerprints can then be used for subsequent analysis and visualisation, e.g., for comparing fingerprints across several sensor positions and for identifying vibrations as global or local properties. In this study, data were collected by sensors on two test turbines and fingerprints were successfully extracted for vibrations with both low and high operational variability. An analysis of sensors on the same blade indicates that fingerprints deviate for positions at large radial distance or at different blade sides and, hence, an evaluation with larger datasets of sensors at different positions is promising. In addition, the results show that distributed measurements on the blades are needed to gain a detailed understanding of blade vibrations and thereby reduce loads, increase energy harvesting and improve future blade design. In doing so, our method provides a tool for analysing vibrations with relation to environmental and operational variability in a comprehensive manner.

Flexible and Vibration Characteristics Simulation for the Large Megawatt Size Wind Turbine Blades

2011 ◽  
Vol 217-218 ◽  
pp. 363-367
Author(s):  
Xu Dong Wang ◽  
Li Cun Wang ◽  
Xian Ming Zhang ◽  
Jun Feng
Keyword(s):  
Wind Turbine ◽  
Wind Power ◽  
Turbine Blades ◽  
Vibration Characteristics ◽  
Wind Turbine Blades ◽  
Fatigue Lifetime ◽  
Aeroelastic Model ◽  
Blade Tip ◽  
Important Significance ◽  
Blade Element

In the development of new large megawatt size wind turbines, aerodynamic and structural reserch is interesting and important for study wind turbine performace and boost the development of wind power. In this paper, the aerodynamic and aeroelastic characteristic of blades is investigated and presented based on Blade Element Momentum and Hamilton theory. Then the flexible characteristics of balde is researched with the aerodynamic and aeroelastic model of the rotor. The flapwise and edgewise displacements, velocities and accelerations of blade tip are simulated and plotted to validate the model which is presented in this paper. The results have very important significance to investigate the vibration and fatigue lifetime of the wind turbine blades.

scholarly journals Aeroelastic Performance Analysis of Wind Turbine in the Wake with a New Elastic Actuator Line Model

Water ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1233
Author(s):  
Ziying Yu ◽  
Zhenhong Hu ◽  
Xing Zheng ◽  
Qingwei Ma ◽  
Hongbin Hao
Keyword(s):  
Wind Turbine ◽  
Open Source ◽  
Turbine Blades ◽  
Wake Flow ◽  
Wind Turbine Blades ◽  
Line Model ◽  
Company Limited ◽  
Blade Tip ◽  
Actuator Line Model ◽  
Turbine Blade Design

The scale of a wind turbine is getting larger with the development of wind energy recently. Therefore, the effect of the wind turbine blades deformation on its performances and lifespan has become obvious. In order to solve this research rapidly, a new elastic actuator line model (EALM) is proposed in this study, which is based on turbinesFoam in OpenFOAM (Open Source Field Operation and Manipulation, a free, open source computational fluid dynamics (CFD) software package released by the OpenFOAM Foundation, which was incorporated as a company limited by guarantee in England and Wales). The model combines the actuator line model (ALM) and a beam solver, which is used in the wind turbine blade design. The aeroelastic performances of the NREL (National Renewable Energy Laboratory) 5 MW wind turbine like power, thrust, and blade tip displacement are investigated. These results are compared with some research to prove the new model. Additionally, the influence caused by blade deflections on the aerodynamic performance is discussed. It is demonstrated that the tower shadow effect becomes more obvious and causes the power and thrust to get a bit lower and unsteady. Finally, this variety is analyzed in the wake of upstream wind turbine and it is found that the influence on the performance and wake flow field of downstream wind turbine becomes more serious.

Parametric Stiffness in Large-Scale Wind-Turbine Blades and the Effects on Resonance and Speed Locking

2020 ◽  
Author(s):  
Ayse Sapmaz ◽  
Brian F. Feeny
Keyword(s):  
Wind Turbine ◽  
Large Scale ◽  
Turbine Blades ◽  
Relative Strength ◽  
Wind Turbine Blades ◽  
Fixed Position ◽  
Horizontal Axis Wind Turbine ◽  
Parametric Effect ◽  
Parametric Effects ◽  
Blade Tip

Abstract This paper is on parametric effect in large scale horizontal-axis wind-turbine blades and speed locking phenomenon for a simplified model of the in-plane blade-hub dynamics. The relative strength of the parametric stiffness is evaluated for actual and scaled-length blades. Fixed-position natural frequencies are found at different rotation angles to show the significance of the gravity’s parametric effect. The ratio of the parametric and elastic modal stiffness is then estimated for the scaled versions of the NREL’s blades for four models to present the relation between the blade size and the parametric effects. The parametric effect on blade tip placements are investigated for superharmonic resonances at orders two and three for blades of various lengths. An analysis of speed-locking is presented, and interpreted for the various blades.

scholarly journals Ice Detection Model of Wind Turbine Blades Based on Random Forest Classifier

Energies ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2548 ◽  
Author(s):  
Lijun Zhang ◽  
Kai Liu ◽  
Yufeng Wang ◽  
Zachary Omariba
Keyword(s):  
Random Forest ◽  
Wind Turbine ◽  
Confusion Matrix ◽  
Turbine Blades ◽  
Random Forest Classifier ◽  
Normal Sample ◽  
Wind Turbine Blades ◽  
Model Based ◽  
Industrial Big Data ◽  
Ice Detection

When wind turbine blades are icing, the output power of a wind turbine tends to reduce, thus informing the selection of two basic variables of wind speed and power. Then other features, such as the degree of power deviation from the power curve fitted by normal sample data, are extracted to build the model based on the random forest classifier with the confusion matrix for result assessment. The model indicates that it has high accuracy and good generalization ability verified with the data from the China Industrial Big Data Innovation Competition. This study looks at ice detection on wind turbine blades using supervisory control and data acquisition (SCADA) data and thereafter a model based on the random forest classifier is proposed. Compared with other classification models, the model based on the random forest classifier is more accurate and more efficient in terms of computing capabilities, making it more suitable for the practical application on ice detection.

scholarly journals Automated Detection of Premature Flow Transitions on Wind Turbine Blades Using Model-Based Algorithms

2021 ◽  
Vol 11 (18) ◽  
pp. 8700
Author(s):  
Ann-Marie Parrey ◽  
Daniel Gleichauf ◽  
Michael Sorg ◽  
Andreas Fischer
Keyword(s):  
Turbulent Flow ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Rotor Blade ◽  
Turbine Blades ◽  
Rotor Blades ◽  
Wind Turbine Blades ◽  
Model Based ◽  
Negative Effect ◽  
Layer Flow

Defects on rotor blade leading edges of wind turbines can lead to premature laminar–turbulent transitions, whereby the turbulent boundary layer flow forms turbulence wedges. The increased area of turbulent flow around the blade is of interest here, as it can have a negative effect on the energy production of the wind turbine. Infrared thermography is an established method to visualize the transition from laminar to turbulent flow, but the contrast-to-noise ratio (CNR) of the turbulence wedges is often too low to allow a reliable wedge detection with the existing image processing techniques. To facilitate a reliable detection, a model-based algorithm is presented that uses prior knowledge about the wedge-like shape of the premature flow transition. A verification of the algorithm with simulated thermograms and a validation with measured thermograms of a rotor blade from an operating wind turbine are performed. As a result, the proposed algorithm is able to detect turbulence wedges and to determine their area down to a CNR of 2. For turbulence wedges in a recorded thermogram on a wind turbine with CNR as low as 0.2, at least 80% of the area of the turbulence wedges is detected. Thus, the model-based algorithm is proven to be a powerful tool for the detection of turbulence wedges in thermograms of rotor blades of in-service wind turbines and for determining the resulting areas of the additional turbulent flow regions with a low measurement error.

scholarly journals Separated Pitch Control at Tip: Innovative Blade Design Explorations for Large MW Wind Turbine Blades

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Ranjeet Agarwala ◽  
Paul I. Ro
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Turbine Blades ◽  
Wind Turbine Blades ◽  
Pitch Control ◽  
Wind Speeds ◽  
Extreme Wind ◽  
Blade Tip ◽  
Low Wind Speeds ◽  
Extreme Wind Speeds

This paper focuses on the deployment and evaluation of a separated pitch control at blade tip (SePCaT) control strategy for large megawatt (MW) wind turbine blade and explorations of innovative blade designs as a result of such deployment. SePCaT configurations varied from five to thirty percent of the blade length in 5 percentage increments (SePCaT5, SePCaT10, SePCaT15, SePCaT20, SePCaT25, and SePCaT30) are evaluated by comparing them to aerodynamical responses of the traditional blade. For low, moderate, high, and extreme wind speed variations treated as 10, 20, 30, and 40 percent of reference wind speeds, rotor power abatement in region 3 of the wind speed power curve is realized by feathering full length blade by 6, 9, 12, and 14 degrees, respectively. Feathering SePCaT30, SePCaT25, SePCaT20, and SePCaT15 by 14, 16, 26, and 30 degrees, respectively, achieves the same power abatement results when compared to traditional blade at low wind speeds. Feathering SePCaT30, SePCaT25, and SePCaT20 by 18, 26, and 30 degrees on the other hand has the same effect at high wind speeds. SePCaT30 feathered to 26 and 30 degrees has the same abatement effects when compared to traditional blade at high and extreme wind speeds.

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