Horizontal Axis Wind Turbine Blade Research Articles

Correction to: Nonlinear modeling analysis of the coupled mechanical strength and stiffness enhancement of composite materials of a Horizontal Axis Wind Turbine Blade (HAWTB)

Correction to: Nonlinear modeling analysis of the coupled mechanical strength and stiffness enhancement of composite materials of a Horizontal Axis Wind Turbine Blade (HAWTB)

Design and Evaluation of Performance Characteristics of a 2kW Small Scale Horizontal Axis Wind Turbine Blade Using Analytical and Numerical Approaches

Design and Evaluation of Performance Characteristics of a 2kW Small Scale Horizontal Axis Wind Turbine Blade Using Analytical and Numerical Approaches

Stress Coupling Analysis and Failure Damage Evaluation of Wind Turbine Blades during Strong Winds

Blades in strong wind conditions are prone to various failures and damage that is due to the action of random variable amplitude loads. In this study, we analyze the failure of 1.5 MW horizontal axis wind turbine blades. The computational fluid dynamics unsteady calculation method is used to simulate the aerodynamic load distribution on the blade. Fluid–structure coupling methods are applied to calculate the blade stress. The results show that the equivalent stress of the blade is the largest when the azimuth angle is 30°, and the maximum equivalent stress is 20.60 MPa. There are obvious stress peaks in six sections, such as r/R = 0.10 (the span length of blade/the full length of the blade = 0.10). The frequency of damage that is caused by the stress in each area of the blade is determined based on the blade damage. The frequency of gel coat cracking in the blade tips and leaves is 77.78% and 22.22%, respectively, and the frequency of crack occurrence is 87.75%, 10.20% and 2.05%, respectively. By combining the stress concentration area and the damage results, the cause of blade damage is determined, which can replace the traditional inspection methods and improve the inspection efficiency.

Design, development and multi-disciplinary investigations of aerodynamic, structural, energy and exergy factors on 1 kW horizontal-axis wind turbine

AbstractContinually increasing demand for energy, coupled with the need for clean environment, has made it mandatory to fall back on efficient conversion of energy from renewable sources. Wind energy is one of the most viable sources of renewable energy. A wind turbine blade, shaped as an airfoil with a streamlined cross-section, can be graded for its aerodynamic efficiency in terms of lift-to-drag ratio. Optimal design and analysis of blades with different airfoil sections is critical for efficient energy extraction. In this paper, computational fluid dynamics (CFD) is used to predict the aerodynamic efficiency of wind turbine blades. To set the basics right, a detailed review of aerodynamics of the 2D airfoils are undertaken: (a) NACA4412, (b) NACA23012 and (c) NACA63215 airfoils. Additionally, a numerical study on structural analysis for a 1-kW horizontal-axis wind turbine blade using finite element analysis (FEA) to assess the initial failure of NACA 63215 airfoil internal structure after optimization was conducted. In the internal structure of the blade, a single spar was included to make the structure more efficient in bending. Structural optimization resulted in bringing the weight down from an initial weight of 5.6 kg to a final design weight of 1.1 kg, i.e. a net saving of more than 4 kg. In addition stress levels in the model also improved with the failure indices turning toward unity. Optimized structural thicknesses in terms of glass fiber-reinforced plastic (GFRP) layers were found within safe limits. From FEA study and based on the von Mises stress distribution on the pressure and suction sides of wind turbine blade from root to tip, the initial failure was found to occur in the overlap edge of root region when the equivalent stress reached to the ultimate stress of the tip region. It was found that a well-designed GFRPs wind turbine blade is very efficient compared with metals/alloys.

A comprehensive review of the application of bio-inspired tubercles on the horizontal axis wind turbine blade

A comprehensive review of the application of bio-inspired tubercles on the horizontal axis wind turbine blade

Nonlinear modeling analysis of the coupled mechanical strength and stiffness enhancement of composite materials of a Horizontal Axis Wind Turbine Blade (HAWTB)

Nonlinear modeling analysis of the coupled mechanical strength and stiffness enhancement of composite materials of a Horizontal Axis Wind Turbine Blade (HAWTB)

Multi-objective optimization of composite airfoil fibre orientation under bending–torsion coupling for improved aerodynamic efficiency of horizontal axis wind turbine blade

Modern multi-megawatt wind turbines have long, slender and flexible blades, which experience significant vibration due to aerodynamic loads. These blades are generally made of composite layups with cambered airfoil sections, which induce elastic and dynamic coupling between bending and torsional modes. In addition to these phenomena, the aerodynamic pitching moment also arises due to the offset of the blade pitch axis from the aerodynamic centre. With this in mind, the present work aims to develop a computationally efficient complete multi-body dynamic aero-servo-elastic model of an onshore horizontal axis wind turbine, including bending–torsion coupling and aerodynamic pitching moment. 3D wind fields are generated using TurbSim, and the responses of the coupled system are solved under different operational scenarios, which signify the impact of the aforementioned coupling. It is found to be particularly detrimental at higher wind speeds than the rated value. But, proper design and implementation of structural layup can enhance the aerodynamic performance of the blade. Finally, the optimal design of composite fibre orientation of a benchmark turbine blade is investigated to show its beneficial effects in load/response mitigation.

Research on the Change of Airfoil Geometric Parameters of Horizontal Axis Wind Turbine Blades Caused by Atmospheric Icing

Icing can significantly change the geometric parameters of wind turbine blades, which in turn, can reduce the aerodynamic characteristics of the airfoil. In-depth research is conducted in this study to identify the reasons for the decline of wind power equipment performance through the icing process. An accurate experimental test method is proposed in a natural environment that examines the growth and distribution of ice formation over the airfoil profile. The mathematical models of the airfoil chord length, camber, and thickness are established in order to investigate the variation of geometric airfoil parameters under different icing states. The results show that ice accumulation varies considerably along the blade span. By environmental temperature drop, the minimum and maximum extents of ice accumulation are observed near the blade root (0.2 R) and the blade tip (0.95 R), respectively (R represents the blade length). The icing process steadily increases the chord length and decreases the airfoil curvature, reaching the largest value at the blade tip region. Furthermore, the maximum curvature is reduced to 41.50% of the original curvature. The maximum camber position of the airfoil moves towards the trailing edge, and the most prominent position occurs at the middle blade region (0.6 R), where it moves back by 19.43%. Ice accumulation steadily increases airfoil thickness. It leads to the maximum thickness growth of 53.40% that occurs at the blade tip region and moves forward to the leading edge by 10%. The research results can provide the required theoretical support for further monitoring the blades operating conditions to ensure reliable wind turbines’ operation.

Study on Structural Performance of Horizontal Axis Wind Turbine with Air Duct for Coal Mine

Considering the characteristics of narrow underground space and energy distribution, based on blade element momentum theory, Wilson optimization model and MATLAB programming calculation results, the torsion angle and chord length of wind turbine blade under the optimized conditions were obtained. Through coordinate transformation, the data were transformed into three-dimensional form. The three-dimensional model of the blade was constructed, and the horizontal axis wind turbine blade under the underground low wind speed environment was designed. The static structural analysis and modal analysis were carried out. Structural design, optimization calculation and aerodynamic analysis were carried out for three kinds of air ducts: external convex, internal concave and linear. The results show that the velocity distribution in the throat of linear air duct is relatively uniform and the growth rate is large, so it should be preferred. When the tunnel wind speed is 4.3 m/s and the rated speed is 224 rad/s, the maximum displacement of the blade is in the blade tip area and the maximum stress is at the blade root, which is not easy to resonate. The change rate of displacement, stress and strain of blade is positively correlated with speed. The energy of blade vibration is mainly concentrated in the swing vibration of the first and second modes. With the increase in vibration mode order, the amplitude and shape of the blade gradually transition to the coupling vibration of swing, swing and torsion. The stress and strain of the blade are lower than the allowable stress and strain of glass fiber reinforced plastics (FRP), and resonance is not easy to occur in the first two steps. The blade is generally safe and meets the design requirements.

Horizontal Axis Wind Turbine Performance Analysis

The present work uses the method of Blade Element Momentum Theory as suggested by Hansen. The method applied to three blade models adopted from Rahgozar S. with the airfoil data used the data provided by Wood D. The wind turbine performance described in term of the thrust coefficient CT, torque coefficient CQand the power coefficient Cp. These three coefficient can be deduced from the Momentum theory or from the Blade element Theory(BET). The present work found the performance coefficient derived from the Momentum theory tent to over estimate. It is suggested to used the BET formulation in presenting these three coefficients. In overall the Blade Element Momentum Theory follows the step by step as described by Hansen work well for these three blade models. However a little adjustment on the blade data is needed. To the case of two bladed horizontal axis wind turbine, Hansen’s approach works well over if the blade radius is RBthe calculation should start from r = 0.1RB.

Design and Performance Analysis of Composite Airfoil Wind Turbine Blade

Abstract
 Small horizontal axis wind turbine rotors with composite airfoil rotor blades were designed and investigated in the present study in order to improve its performance in low wind speed and low Reynolds number (Re) conditions for standalone system. The geometrical and aerodynamic nature of a single airfoil small horizontal axis wind turbine blade curtails efficient energy harnessing of the rotor blade. The use of composite airfoil rotor blade improves energy production but imposes uncertainty in determining an optimal design angle of attack and the off design aerodynamic behaviour of the rotor. This research investigated the effects of two airfoils used at different sections in a composite blade and determined the blade’s optimal design angle of attack for maximum power generation. The wind turbine rotor blades were designed using blade element momentum (BEM) method and modelled by SolidWorks software. The SG6042 and SG6043 airfoils were used for the composite airfoil blades. Five wind turbines were designed with rotor blades of design angles of attack from 3° to 7°. The five wind turbine blades were simulated in computational fluid dynamics to determine the optimal design angle of attack. The composite airfoil wind turbine blade showed improved performance, whereas, the wind power generated ranged from 4966 W to 5258 W and rotor power coefficients ranged from 0.443 to 0.457. The blade with design angle of attack of 6° showed highest performance.
 Keywords: composite airfoil, lift-to-drag ratio, pressure coefficient, Reynolds number, design angle of attack.

Quantitative impact of a micro-cylinder as a passive flow control on a horizontal axis wind turbine performance

Adding micro-cylinder as a passive flow control is a new trend to enhance the power output of wind turbines. The impact of adding micro-cylinder, with different configurations, around horizontal axis wind turbine blade (HAWT) is examined using 3-dimensional simulations. The conventional turbine National Renewable Energy Laboratory (NREL Phase II) straight-bladed wind turbine is selected to validate the present numerical arrangements, where it hasn't been tested before with adding micro-cylinder. The Reynolds Average Navier-Stokes (RANS) equations for steady-state incompressible flow combined with Shear Stress Transport (k-ω SST) turbulence model are employed for the current numerical analysis. In this study, a parametric study is conducted for different diameters and locations of micro-cylinder. In total, seven cases are examined. The influence of micro-cylinder size is examined by changing the cylinder diameter (three different diameters, diameter/chord = 0.0131, 0.0175, 0.022). It has been found that the output power increases with decreasing the micro-cylinder diameter. The effect of micro-cylinder locations is investigated by introducing four different cases (four different locations around the leading edge). The power output increases for all cases. Additionally, it has been found that locating the micro-cylinder on the pressure side has less effect on the power output comparing to locating it on front of the blade leading edge.

Experimental investigations of winglet effects on blade geometry of small horizontal axis wind turbine rotors

In this research work, the investigation and optimization of small horizontal axis wind turbine blade at low wind speed is pursued. The experimental blades were developed using the 3D printing additive manufacturing technique. The airfoils E210, NACA2412, S1223, SG6043, E216, NACA4415, SD7080, SD7033, S1210 and MAF were tested at the wind speed of 2-6 m/s. The airfoils and optimum blade geometry were investigated with the aid of the Xfoil software at Reynolds number of 100,000. The initial investigation range included tip speed ratios from 3 to 10, solidity from 0.0431 – 0.1181 and angle of attacks from 2o to 20o. Later on these parameters were varied in MATLAB and Xfoil software for optimization and investigation of the power coefficient, lift coefficient, drag coefficient and lift to drag ratio. The cut-in wind speed of the rotors was 2 and 2.5 m/s with the winglet-equipped blades and without winglets. It was found that the E210, SG6043, E216 NACA4415 and MAF airfoil displayed better performance than the NACA 2412, S1223, SD7080, S1210 & SD7003 for the geometry optimized for the operating conditions and manufacturing method described.

New airfoils for micro horizontal-axis wind turbines

In this study, small horizontal-axis wind turbine blades operating at low wind speeds were optimized. An optimized blade design method based on blade element momentum (BEM) theory was used. The rotor radius of 0.2 m, 0.4 m and 0.6 m and blade geometry with single (W1 & W2) and multistage rotor (W3) was examined. MATLAB and XFoil programs were used to implement to BEM theory and devise a six novel airfoil (NAF-Series) suitable for application of small horizontal axis wind turbines at low Reynolds number. The experimental blades were developed using the 3D printing additive manufacturing technique. The new airfoils such as NAF3929, NAF4420, NAF4423, NAF4923, NAF4924, and NAF5024 were investigated using XFoil software at Reynolds numbers of 100,000. The investigation range included tip speed ratios from 3 to 10 and angle of attacks from 2° to 20°. These parameters were varied in MATLAB and XFoil software for optimization and investigation of the power coefficient, lift coefficient, drag coefficient and lift-to-drag ratio. The cut-in wind velocity of the single and multistage rotors was approximately 2.5 & 3 m/s respectively. The optimized tip speed ratio, axial displacement and angle of attack were 5.5, 0.08m & 6° respectively. The proposed NAF-Series airfoil blades exhibited higher aerodynamic performances and maximum output power than those with the base SG6043 and NACA4415 airfoil at low Reynolds number.

Influence of leading-edge tubercles on the aerodynamic performance of a horizontal-axis wind turbine: A numerical study

Leading-edge tubercles on the humpback whale pectoral fin are known to have aerodynamic benefits, particularly in the post-stall regime. In this research, a horizontal-axis wind turbine blade was modelled with tubercles distributed on its leading edge to mimic the humpback whale pectoral fin. A parametric study of the effect of tubercles on the reference NREL Phase VI wind turbine was conducted via computational fluid dynamics. Three parameters—amplitude, wavelength, and tubercle location along the blade span—were varied. The results showed that tubercles have negative effects on the turbine performance at wind speeds (V∞) ≤ 7 m/s. However, when tubercles are placed over 60% of the blade span, the backflow area can be eliminated at V∞ = 10 m/s. It is found that the vortices in the stable-flow zone over the suction surface can be reduced when tubercles of a relatively small amplitude-wavelength ratio are employed, thereby maintaining turbine performance. Compared with the reference blade, tubercles provided benefits at higher wind speeds. The generated vortices due to the presence of tubercles, leading to both blockage effects and stall delay. The results revealed that the pressure on the suction surface of the tubercled blade decreases, thereby increasing lift and enhancing the turbine performance.

Nonlinear vibration analysis of horizontal axis wind turbine blades using a modified pseudo arc-length continuation method

The horizontal axis wind turbine (HAWT) blades are exposed to parametric and direct excitations of harmonic nature due to the gravity and aerodynamic loads. Hence, the study of the periodic response of the HAWT blades under these operating loads is of great importance in structural design. In this paper, a new computationally efficient dynamic model for the blade is presented including the pre-twist effects. The Rayleigh-Ritz technique is applied to the derived dynamic model and a reduced order model (ROM) is devised in a systematic manner. An efficient method based on the pseudo arc-length continuation method is introduced to find out the edge-wise and flap-wise amplitude-frequency response (AFR) curves of the blade under harmonic wind inflow. Furthermore, the forced vibration of the blade under different operating loads including gravity, centrifugal and aerodynamic loads (due to the uniform and shear wind inflows) is studied separately. Applying the proposed method, the effects of structural damping, nonlinear terms, pre-twist ratio, and cyclic excitation due to the gravity force as well as the centrifugal force on the AFR curves are investigated. Eventually, the dynamic model and the presented method for the frequency analysis are validated with the available data.

Computational And Experimental Investigation of Lotus-Inspired Horizontal-Axis Wind Turbine Blade

In the firm belief that the world needs green, renewable and more efficient energy resources, the present paper is concerned with developing a new design for horizontal-axis wind-turbine (HAWT) blades. The flower of Nelumbo nucifera (Sacred Lotus) was the motive for the present design of a three-blade wind turbine. Nelumbo Nucifera flower has an aerodynamically appropriate structure, which qualifies the flower to be the nature-inspiration for the present research. A computational fluid dynamics (CFD) simulation was applied in order to ensure the ability and eligibility of the proposed solution and estimate real world's results. The performance of the blade airfoil can be improved by applying the Lotus flower's structural design and modifying the blade straightening. The experimental findings demonstrated performance enhancement by 31.7% compared to NACA 2412 airfoil.

Parametric study of flapwise and edgewise vibration of horizontal axis wind turbine blades

In this paper, flapwise and edgewise vibrations of a horizontal axis wind turbine (HAWT) blade are studied. Rayleigh-Ritz method is used in which; orthogonal mode functions of the Euler-Bernoulli beam having fixed-free boundary are introduced into the Lagrange function and then the dynamic equations are derived. Effect of gravity, pitch angle, centrifugal stiffening, and rotary inertia are considered. Nondimensional equations are obtained by defining nondimensional parameters like; natural frequency, blade rotation, slenderness ratio, and simple pendulum frequency. The stiffness term of the natural frequency has two speed dependent elements and it is shown that, for small pitch angles, flapwise natural frequencies of the blade are increased by the increasing blade speed while the edgewise natural frequencies of the blade are decreased with the increasing blade speed. Pitch angle values ranging from 0° to 15° has negligible effect on the nondimensional natural frequencies of the blade up to the nondimensional blade speed of 4. Since the natural frequencies are the function of the blade speed, rotor critical speeds should be calculated with Campbell diagrams. Vibrational response of the blade tip to the gravity is dominant and much greater than that of the wind speed in the edgewise and flapwise vibration.

Design and Analysis of Horizontal Axis Wind Turbine (HAWT) Blades Using CFD

Abstract: Within the current years wind power is extensively taken into consideration and applied as one of the most promising renewable electricity assets. In the recent studies have a look at, aerodynamic analysis of horizontal axis turbine is achieved with the aid of using cfd. Blades which can be often possible for industrial grade wind turbines embody a directly span-wise profile in conjunction with airfoil fashioned go sections. Wind tunnel test is applied in order to check aerodynamic efficiency wind turbine blade. The goal of this study is to design a wind turbine. The layout manner includes the choice of the sun machine for max efficiency and wind turbine kind and the determination of the blade airfoil, pitch attitude distribution along the radius, and chord duration distribution along the radius. The pitch angle and chord period distributions are optimized primarily based on conservation of angular momentum and principle of aerodynamic forces on an airfoil. Blade element momentum (BEM) principle is first derived then used to conduct a parametric observe to be able to determine if the optimized values of blade pitch and chord period create the maximum green blade geometry. This work includes a discussion of the most important parameters in wind turbine blade layout to maximize efficiency. Keywords: Wind Turbine, HAWT, BEM Theory, Parametric Study, Maximization of efficiency etc.

Bionic coupling design and aerodynamic analysis of horizontal axis wind turbine blades

AbstractWith millions of years of evolution, owls have developed many excellent characteristics in terms of their flight. The speed of an owl in flight is similar to the relative speed of the blade of a small wind turbine with respect to air. Therefore, the owl wing airfoil is selected as the design airfoil of the wind turbine blade to reduce the flow separation under low Reynolds number. In this study, we analyze an owl wing‐section airfoil and the non‐smooth leading‐edge shape of an owl's wing, and implement an orthogonal optimum design to optimize the wavelength and amplitude of the non‐smooth leading edge. We extract the cross‐sectional features of the airfoil and the non‐smooth leading‐edge shape of the wing. Based on the orthogonal optimum design results, we determine the optimal combination of the wavelength, amplitude, and airfoil, and then design a horizontal‐axis wind turbine blade through bionic coupling. The flow field at different tip speed ratios (TSRs) is simulated using the turbulence model at the rated wind speed. The results show that the power coefficient () of the bionic wind turbine at a high tip speed ratio is 17.7% higher than that of the standard type. Furthermore, we analyze the operation of the turbine at TSRs of 2 and 5. At a high TSR, the leading edge bulge of the bionic wind turbine blade can change the flow direction distribution of the airflow on the blade surface, make the airflow to adhere to the suction surface, and then reduce the stall area on the suction surface of the blade. Thus, the wind turbine produces higher torque, thereby generating higher power.