A Study of Load Comparison of Two- and Three-Bladed Rotor Wind Turbines

2014 ◽  
Author(s):  
Jin Woo Lee ◽  
Brett Andersen ◽  
Musarrat Jehan ◽  
Abdollah Afjeh ◽  
Efstratios Nikolaidis
Keyword(s):  
Wind Turbine ◽  
Fatigue Damage ◽  
Wind Turbines ◽  
Maximum Load ◽  
Blade Design ◽  
Baseline Design ◽  
Design Load ◽  
Load Effects ◽  
Bladed Rotor ◽  
Simulation Results

In this study, load effects of identically rated power two- and three-bladed rotor wind turbines are computed and compared using the requirements of the IEC61400-3 standard. The two-bladed turbine includes a teeter mechanism. Moreover, an improved blade design is considered for the two-bladed turbine. A series of wind turbine operational simulations was performed for the wind turbine models under selected design load cases of IEC61400-3 standard. Loads were computed using the FAST code. The series of simulations were driven and post-processed using the FAST_SM code. Additionally, fatigue damages of the two- and three-bladed rotor wind turbines were computed. The study showed that the maximum load effects and fatigue damage of the two-bladed wind turbine generally increased compared to the three-bladed turbine. The simulation results also showed that the baseline design blade of the two-bladed wind turbine requires improvement in order to sustain the computed large load effects.

Comparative Study of Two-Bladed Upwind and Downwind Turbines Using the NREL Reference Wind Turbine

2014 ◽  
Author(s):  
Jin Woo Lee ◽  
Musarrat Jehan ◽  
Brett Andersen ◽  
Abdollah Afjeh ◽  
Efstratios Nikolaidis
Keyword(s):  
Wind Turbine ◽  
Fatigue Damage ◽  
Wind Turbines ◽  
Lower Cost ◽  
Baseline Design ◽  
Cost Of Energy ◽  
Lower Load ◽  
Load Effects ◽  
Bladed Rotor ◽  
Tower Shadow

Two-bladed wind turbines offer the potential for a lower cost of energy compared with three-bladed rotor turbines. This investigation was conducted to quantify the differences between the loads of upwind and downwind two-bladed wind turbines operating under random wind conditions. This paper focuses on a comparison of maximum and average loads that can cause first excursion failure, and loads that can cause fatigue failure. In this study, upwind and downwind turbines with two bladed rotors are compared. The NREL 5MW reference wind turbine was used as a baseline design and was modified as necessary to design a two bladed upwind wind turbine. The tower shadow effect was considered for the downwind turbine. The IEC61400-3 standard load cases were used to define the loading conditions for the wind turbine simulations. The computed load effects generally showed that the downwind configuration had lower load effects. Moreover, fatigue damage was lower for the two-bladed downwind turbine compared to the upwind turbine.

Improvement in Savonius Wind Turbines Efficiency by Modification of Blade Designs—A Numerical Study

2019 ◽  
Vol 142 (6) ◽  
Author(s):  
Praveen Laws ◽  
Jaskaran Singh Saini ◽  
Ajit Kumar ◽  
Santanu Mitra
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Power Efficiency ◽  
Numerical Study ◽  
Speed Ratio ◽  
Published Data ◽  
Blade Design ◽  
Simple Modification ◽  
Mesh Structure ◽  
Flow Equations

Abstract Savonius wind turbines are special class of vertical axis wind turbines (VAWTs). These are low-cost drag-driven turbines and are known to be inefficient. It is proposed in this study that a simple modification to the turbine blade design can yield a significant improvement in power efficiency. The performance of the new design is extensively studied on openfoam-v1812, a popular open source computational fluid dynamics (CFD) library. The flow equations coupled with equations of rotation of the turbine are solved on an overset mesh framework. This study also serves as a validation of recently released overset support in openfoam. The turbulence is incorporated by coupling Reynolds-averaged Navier–Stokes (RANS) with shear stress transport (SST) κ − ω eddy viscosity turbulence model. The turbulence parameters are set to produce a flow with the Reynolds number, Re = 4.8 × 105. To have better confidence in simulations, this study also presents a comparison of numerical flow over conventional Savonius turbine designs with the published data. It is observed that a majority of CFD analysis on wind turbine designs are performed for the fixed tip speed ratio on a traditional static mesh structure. But, in this CFD study, a wind-driven rotation of Savonius turbine is simulated on an overset dynamics approach. The results of the study are compared and discussed based on the predicted moment and power coefficients, pressure variation on the blades, flow velocity field, and wake analysis. The study indicates that the blade design presented here has a potential to increase the power efficiency of a Savonius wind turbine by 10–28%.

scholarly journals Vibration Reduction Strategy for Offshore Wind Turbines

2020 ◽  
Vol 10 (17) ◽  
pp. 6091
Author(s):  
Haoming Liu ◽  
Suxiang Yang ◽  
Wei Tian ◽  
Min Zhao ◽  
Xiaoling Yuan ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Output Power ◽  
Wind Turbines ◽  
Reference Signal ◽  
Offshore Wind ◽  
Wave Load ◽  
Offshore Wind Turbines ◽  
Pitch Control ◽  
Simulation Results ◽  
Aerodynamic Torque

The operational environment of offshore wind turbines is much more complex than that of onshore wind turbines. Facing the persistent wind and wave forces, offshore wind turbines are prone to vibration problems, which are not conducive to their long-term operation. Under this background, first, how the wave affects the vibration characteristics of offshore wind turbines is analyzed. Based on the existing wave and wave load models, we analytically show that there exist fluctuating components related to the hydrodynamic frequency in the aerodynamic load and aerodynamic torque of offshore wind turbines. Simulation results based on a GH Bladed platform further validates the analysis. Second, in order to reduce the joint impacts of the wave, wind shear and tower shadow on the wind turbine, a variable pitch control method is proposed. The integrated tower top vibration acceleration signal is superimposed on the collective pitch reference signal, then the triple frequency (3P) fluctuating component of the wind turbine output power and the azimuth angle of each blade are converted into the pitch angle adjustment signal of each blade, which is superimposed on the collective pitch signal for individual pitch control. The simulation results show that the proposed pitch control strategy can effectively smooth the fluctuation of blade root flap-wise load caused by wind and wave, and significantly reduce the fluctuation of aerodynamic torque and output power of offshore wind turbines.

scholarly journals Simulating the Speed control System of Wind Turbines Using MATLAB Software

2020 ◽  
Vol 4 (2) ◽  
pp. 1-6
Author(s):  
Seyed Mojtaba Hosseini Bafoghi ◽  
Hamidreza Khezri
Keyword(s):  
Mathematical Model ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Pid Controller ◽  
Electrical Energy ◽  
Induction Generator ◽  
Rotor Speed ◽  
Output Frequency ◽  
Static Loads ◽  
Simulation Results

In this paper, a mathematical method is proposed to control the output frequency of a self-excited induction generator using wind turbines and static loads. A dynamic model of the wind turbine is implemented to model the Connections and fittings of the wind turbine to convert the wing energy to electrical energy. Also a PID controller system is proposed to control the rotor speed of the wind turbine. The proposed mathematical model is developed in MATLAB-Simulink software. The simulation results showed that the developed controller can be used to control the wind turbine velocity.

The Effect of Turbulence Model on the Response of a Large Floating Wind Turbine

2017 ◽  
Author(s):  
Lene Eliassen ◽  
Erin E. Bachynski
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Fatigue Damage ◽  
Turbulence Model ◽  
Wind Turbines ◽  
Low Frequency ◽  
Turbulence Models ◽  
Line Tension ◽  
Offshore Wind ◽  
Mooring Line

The wind turbine design standards advise choosing one of two recommended turbulence models for load simulations of offshore wind turbines. The difference in fatigue loads for the two turbulence models is relatively small for bottom-fixed wind turbines, but some floating wind turbines show a higher sensitivity to the chosen turbulence model. In this study, the motions and mooring line fatigue damage of two semi-submersible floating wind turbines are investigated for three different wind speeds: 8 m/s, 14 m/s and 20 m/s, and three different wave states for each wind speed. For both concepts, the CSC 5 MW and the CSC 10 MW, the low-frequency surge response is important for the mooring line tension, and the simulations using the Kaimal turbulence model give the largest variation in tension at the surge eigenfrequency. However, using the Mann turbulence model in the load simulations give a higher response in the range of the blade passing frequency (3P). The CSC 10 MW has a higher aerodynamic thrust relative to the CSC 5 MW, and will therefore have a larger surge response at the lower frequencies than the CSC 5 MW. At the lowest wind speed, where the variation in mooring line tension at surge eigenfrequency is high, the fatigue damage is larger if the Kaimal turbulence model is applied to the load simulations. However, at the highest wind speed, using the Mann turbulence model in the simulations, give a higher mooring line fatigue damage.

scholarly journals Metodología para el Modelado y simulación de pruebas de fatiga en álabes de aerogeneradores de baja potencia

2019 ◽  
pp. 23-32
Author(s):  
Nelson Octavio Ruiz-Nucamendi ◽  
Jose Billerman Robles-Ocampo ◽  
Perla Yasmin Sevilla-Camacho ◽  
Luis Alberto Morales-Alias
Keyword(s):  
Low Power ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Fatigue Analysis ◽  
Horizontal Axis ◽  
Blade Design ◽  
Safety Factors ◽  
Horizontal Axis Wind Turbine ◽  
Load Model ◽  
Convergence Method

This article presents the design, simulation and fatigue analysis of various aerodynamic profiles used in low power wind turbines. For this purpose, the model of a blade of a horizontal axis wind turbine with a nominal power of 5 kW is developed. The analysis of the lift, drag and power coefficients of the aerodynamic profiles was carried out with the XFLR5 software. The methodology used for the blade design is based on the interactions and convergence method called BEM. Also, to simulate the structural and aerodynamic part of the element, the QBlade program was used. With the main objective of ensuring that the fatigue safety factors mentioned in the IEC 61400 standard are achieved, the Simplified Load Model was applied. The maximum fatigue value of 21,421.66 N and the maximum flapwise moment value of 698.41 Nm were obtained.

scholarly journals Study on the Motion Characteristics of 10 MW Superconducting Floating Offshore Wind Turbine Considering 2nd Order Wave Effect

Energies ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 6070
Author(s):  
Youngjae Yu ◽  
Thanh Dam Pham ◽  
Hyunkyoung Shin ◽  
Kwangtae Ha
Keyword(s):  
Wind Turbine ◽  
Test Data ◽  
Model Test ◽  
Wind Turbines ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Strong Wind ◽  
Floating Offshore Wind Turbine ◽  
Simulation Results ◽  
Motion Characteristics

Recently, several countries have made commitments to move to a net-zero emission by the year 2050 in a response to climate change. Among various renewable energy systems to realize the target, wind energy system has been gaining much attention as a favorable alternative source to fossil fuel energy. In particular, many floating offshore wind turbines (FOWT) are expected to be installed because of vast installation resources without water depth limit conditions, stable and strong wind resources, relatively low constraints on noise emission, and space restriction compared to onshore wind turbines. In this study, a 10 MW superconducting floating offshore wind turbine was modeled with a 1/90 scale ratio and was experimentally tested at the Ocean Engineering Widetank of the University of Ulsan. The model calibration of the scaled model was performed with free decay test and showed a good correlation with simulation results calculated from FAST V8 of NREL. The motion characteristics of the 10 MW superconducting FOWT semi-submersible type platform was investigated under regular waves and irregular waves through the comparison of model test data and simulation results. The study on the motion characteristics of the model showed that the simulation considering the 2nd order wave effects to hydrodynamic forces and moments provided better accuracy close to the model test data.

Load Calculation on Wind Turbines: Validation of Flex5, Alaska/Wind, MSC.Adams and SIMPACK by Means of Field Tests

2014 ◽  
Author(s):  
János Zierath ◽  
Roman Rachholz ◽  
Christoph Woernle ◽  
Andreas Müller
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Electrical Power ◽  
Great Influence ◽  
Field Tests ◽  
Early Application ◽  
Iterative Development ◽  
Measurement Results ◽  
Simulation Results ◽  
Turbine Design

Load calculations on wind turbines are an essential part of its development. In the preliminary design phase simplified multibody models are used for the estimation of the interface loads. The interface loads are used within an iterative development loop to design the components of the wind turbine such as gearbox, blades, tower and so on. Due to the early application of load calculations within the development process, the quality of the simulation results has a great influence on the wind turbine design. In this contribution the simulation results of the multibody codes alaska/Wind, MSC.Adams and SIMPACK are compared with measurements obtained from a prototype of a 2.05 MW wind turbine developed by W2e Wind to Energy. Furthermore, simulation results of the special wind turbine design code Flex5, developed at the Technical University of Denmark Copenhagen, are taken into account. A statistical and dynamical evaluation of the simulation and measurement results has been done. Due to the use of the same controller procedures as used on the physical wind turbine, the wind turbine models show almost the same behaviour (electrical power, pitch angle, rotor speed) as the wind turbine in the field. Differences occur during the evaluation of the interface loads due to the different kinds of wind turbine modelling.

A review on fatigue damages in the wind turbines: Challenges in determining and reducing fatigue failures in wind turbine blades

2019 ◽  
Vol 44 (4) ◽  
pp. 434-451
Author(s):  
Karthikeyan Ravikumar ◽  
Rajkumar Subbiah ◽  
Nalini Ranganathan ◽  
Joseph Bensingh ◽  
Abdul Kader ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Crack Growth ◽  
Fatigue Damage ◽  
Wind Turbines ◽  
Turbine Blades ◽  
Wind Turbine Blades ◽  
Aerodynamic Loads ◽  
The World ◽  
Fatigue Loads ◽  
Fatigue Failures

The wind energy has been recognised as one of the rising sustainable energies in the world. The wind turbines are subjected to high aerodynamic loads and they cause vibrations due to the wake formation. The magnitude of the applied loads has significant effects on the crack propagation. The fatigue loads have been identified as one of the key sources of damage, with delamination as the main cause for the failure of the turbine blades. The article presents a review of fatigue damages that have been experienced in the wind turbine blades, and factors that are influenced due to the fatigue loads are discussed. The causes and effects of the fatigue loads have been highlighted, and the ways for preventing the fatigue damage by improving the design lifetime are mainly concentrated in review. The overall review gives an idea for determining and reducing the crack growth in wind turbine blades.

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