scholarly journals Modal Analysis of Vertical Wind Turbine Blade

2018 ◽  
Vol 217 ◽  
pp. 01003 ◽  
Author(s):  
Lee Zhou Yi ◽  
Choe-Yung Teoh

Wind turbines cannot simply be installed in Malaysia due to low wind speed condition. the project has analyzed the existing wind turbine blade (Aeolos-V 1k) design based on modal properties using computational approach (ANSYS Workbench) and redesign it. the modal analysis is simulated to observe natural frequency and corresponding mode shaped of the system under free vibration. the flow induced vibration can cause blade failure due to resonance or fatigue. Fluid Structural Interaction (FSI) ANSYS is used to the determined the interaction between the wind flow and the blade. Harmonic Response ANSYS is used to analyze the frequency response of the blade under wind induced vibration. After modification, the first mode has increased from 91.42 Hz to 102.12, since it is more than 50.92 Hz (Turbine maximum operating frequency), resonance would not occur during operating condition. the Aeolos-V’s blade has been modified by using. teak wood material and. redesign the blade for weight. reduction and aim for lower blade cost. the weight of modified blade has reduced 72.8 % after using teak wood and the efficiency of the wind turbine also increased. Modified design has been tested under Malaysia maximum wind speed of 9.44 m/s, the yield stress of teak wood (10.3 MPa) is higher than the maximum stress (4.2 MPa) obtained under force vibration which gives safety factor of 2.4. Hence, modified blade is reliable, efficient and more economic for Malaysia.

Author(s):  
Jiale Li ◽  
Xiong (Bill) Yu

This paper describes the feasibility analyses of an innovative, extensible ‘smart’ blade technology aims to significantly improve the wind turbine energy production. This innovative ‘smart’ blade will be extended at low wind speed to harvest more wind energy. It will be retracted to its original shape above rated wind speed, to protect the blade from possible damages under high wind speed. The extended blade, however, will inevitably increase the fatigue damage of the wind turbine blade of which fatigue demand, which often controls the design requirement of wind turbine blade. A rain-flow counting method is used for calculating stress range cycles during turbine blade operation. The analyzes model in the research is built based on a 100 kW utility-scale wind turbine installed on the campus of Case Western Reserve University with a data acquisition system installed on the wind turbine tower to monitor the operation data continuously over the years. In this analyses, the data set consists of four years’ wind speed data at 10-minutes time interval and blade rotational speed from March 2014 to February 2015 have been used. The results show that the fatigue damage of this extensible blade increased is acceptable considering its increased power output.


2021 ◽  
pp. 0309524X2110116
Author(s):  
Oumnia Lagdani ◽  
Mostapha Tarfaoui ◽  
Mourad Nachtane ◽  
Mourad Trihi ◽  
Houda Laaouidi

In the far north, low temperatures and atmospheric icing are a major danger for the safe operation of wind turbines. It can cause several problems in fatigue loads, the balance of the rotor and aerodynamics. With the aim of improving the rigidity of the wind turbine blade, composite materials are currently being used. A numerical work aims to evaluate the effect of ice on composite blades and to determine the most adequate material under icing conditions. Different ice thicknesses are considered in the lower part of the blade. In this paper, modal analysis is performed to obtain the natural frequencies and corresponding mode shapes of the structure. This analysis is elaborated using the finite element method (FEM) computer program through ABAQUS software. The results have laid that the natural frequencies of the blade varied according to the material and thickness of ice and that there is no resonance phenomenon.


2021 ◽  
pp. 23-34
Author(s):  
M.J. Pawar ◽  
Amar Patnaik ◽  
Vikas Kukshal ◽  
Ashiwani Kumar ◽  
Vikash Gautam

Author(s):  
R. S. Amano ◽  
Ryan J. Malloy

Recently there has been an increase in the demand for the utilization of clean renewable energy sources. This is a direct result of a rise in oil prices and an increased awareness of human induced climate change. Wind energy has been shown to be one of the most promising sources of renewable energy. With current technology, the low cost of wind energy is competitive with more conventional sources of energy such as coal. This however is only true in areas of high wind density. These areas are not as abundant and therefore the number of profitable sites is limited. This paper explores the possibility increasing the number of profitable sites by optimizing wind turbine blade design for low wind speed areas. The two methods of optimization that are investigated are first, optimizing the angle of attack and chord length for a given airfoil cross section at different positions along the blade and second implementing a swept blade profile. The torque generated from a blade using only the first optimization technique is compared to that generated from a blade using both techniques as well as that generated by NTK500/41 turbine using LM19.1 blades. Performance will be investigated using the CFD solver FLUENT.


2020 ◽  
Vol 142 (10) ◽  
Author(s):  
Hamid Khakpour Nejadkhaki ◽  
John F. Hall

Abstract A control framework and integrative design method for an adaptive wind turbine blade is presented. The blade is adapted by actively transforming the twist angle distribution (TAD) along the blade. This can alleviate fatigue loads and improve wind capture. In this paper, we focus on wind capture. The proposed design concept consists of a rigid spar that is surrounded by a series of flexible blade sections. Each section has two zones of stiffness. The sections are actuated at each end to deform the TAD. A quasi-static control technique is proposed for the TAD. The controller sets the position of the blade actuators that shape the TAD during steady-state operation. A design procedure is used to define the required TAD as a function of the wind speed. This is based on an optimization procedure that minimizes the deviation between the actual TAD and that found in the aerodynamic design. The design inputs for this optimization problem include the stiffness for each zone of the section, and the actuator locations along the blade. Given the optimal TAD at each wind speed, the free position of the blade is established using a dynamic programming technique. The position is selected based on minimal actuation energy according to wind conditions at any installation site. The proposed framework is demonstrated using a National Renewable Energy Laboratory (NREL) certified wind turbine model with recorded wind data. An increase in efficiency of 3.8% with only a deviation of 0.34% from the aerodynamic TAD is observed.


2014 ◽  
Vol 889-890 ◽  
pp. 221-224
Author(s):  
Gao Hua Liao ◽  
Jian Zhong Wu ◽  
Yong Jun Yu

According to the principle of equivalent, the approach to draw up the fatigue test loading spectrum of wind turbine blade is presented. Analysis of wind load characteristics, based on ARMA (Autoregressive Moving Average Model) for the simulation of wind speed, wind load simulation example is given. Using Bladed software, the wind speed-time history is converted to a moment-time history that is the equivalent of blade root.Using data compression technology and the rain flow counting algorithm, load represented by a 2D matrix examples is given.The one-dimensional symmetry loading spectrum draw up, the complexity can be simplified, and provides the necessary foundation for fatigue life analysis.


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