Horizontal Axis Wind Turbine Blade Research Articles

Simulation of unsteady ice accretion on horizontal axis wind turbine blade sections in turbulent wind shear condition

This study presents a comprehensive simulation approach to quantify power losses in horizontal axis wind turbines under environmental icing conditions. It investigates how wind shear and turbulence affect a 2.5 MW wind turbine's performance, particularly under ice accretion. Turbulence intensity, ranging from 1% to 20%, impacts the relative flow fluctuations and angle of attack on the blade sections, influencing the aerodynamic penalty ratio. The incoming wind speed and the flow angle at various blade sections were determined using the unsteady blade element momentum method, considering vortex induction effects and Prandtl and Glauert corrections. For ice accretion analysis, a fully unsteady simulation of computational grid motion due to ice accretion was performed, along with the solution of the multiphase flow of water dispersed particles in cold air, derived from the psychrometric chart. The findings highlight the significant impact of the incoming turbulent wind fluctuations on the dispersion of the ice shape formed at sections corresponding to their radial position on the blade according to the momentary angle of attack fluctuations. The formation of ice profiles along the blade has led to a subsequent degradation in the aerodynamic efficiency of the blade sections, which is directly proportional to the escalation in turbulence intensity. This phenomenon leads to a continual reduction in the power output of the wind turbine. This research provides valuable insights into the performance of wind turbines under icing conditions in real wind fluctuations.

Studying and analysis of deformation and stresses in horizontal-axis wind turbine using fluid-structure interaction method

Fluid-structure interaction (FSI) studies have become an important tool in the development of wind turbine blades as well as for analyzing and optimizing Horizontal Axis Wind Turbine (HAWT). The most essential elements for estimating the turbine blade strength to withstand extreme wind loads and aerodynamic performance are the blade deformation and the associated stresses. This study aims to compare the strength and analyze the deformation behavior of two models of HAWT blades. A three-dimensional model was created and loaded into a Finite Element (FE) model for analysis. The Computational Fluid Dynamics (CFD) investigation was coupled with the structural model using one-way FSI. In this article, the effect of the aerodynamics on the blade surface of a small HAWT has been studied numerically and experimentally. The airfoil used for the blade profile is S826 airfoil. To provide an appropriate displacement for static measurements, the blade in the experimental investigation is made of thermoplastic polyurethane material (TPU). It is noted that the current experimental findings verify the simulation results, and a comparison between the simulations and the experimental findings reveals a reasonable agreement. The numerical simulations are also implemented on a HAWT epoxy E-glass unidirectional (EEGUD) material. It can be concluded from this study that the blade deformation and stress on the blades are related to the wind speed. The deformation along the span length exhibits nonlinear variation that gradually increases from the blade root and reaches its maximum at the blade tip position. The tip deflection and equivalent stress were found to increase with an increase in wind speed. The dynamic analysis at different tip speed ratios shows the highest deformation at λ = 4, for wind speed of 20 m/s.

Optimization Design of Bionic Leading-edge Protuberances on Horizontal Axis Wind Turbine Blades

Abstract The complex operating environments of horizontal axis wind turbines has made the phenomenon of blade flow separation more obvious. As a passive flow control method, the bionic humpback whale leading-edge protuberances have been shown to effectively enhance the performance of the wind turbine. This study employs a multi-objective genetic algorithm and Computational Fluid Dynamics method to analyse the impact of leading-edge protuberances on the aerodynamic performance and flow characteristics of the blades. The results indicate a significant improvement in blade performance after optimization in the wind turbine’s output power. The streamwise vortices generated by the bionic protuberances not only reduce the suction surface pressure, but also suppress the spanwise flow over the blade surface. The length of the flow separation Region is reduced from 0.410 to 0.368 radius. In the process of wind speed change, the tangential forces on the bionic blade exhibit a wave-like variation. The bionic protuberance alters the pressure coefficient of the position. Compared with the original blade, the pressure coefficient of the trough sections on both sides of the bionic blade protuberance is improved. In this study, the bionic protuberance applied to the leading-edge of horizontal-axis wind turbine blades is proposed for the first time, and holds practical value for guiding practical applications.

Characterization of the Mechanical Properties of Fiberglass/Epoxy Prepreg Composites as Horizontal Axis Wind Turbine Blade Material: Influence of Fiber Orientation on Impact and Bending Strength

Characterization of the Mechanical Properties of Fiberglass/Epoxy Prepreg Composites as Horizontal Axis Wind Turbine Blade Material: Influence of Fiber Orientation on Impact and Bending Strength

Influence of control system on aerodynamic characteristics and elastic deformation of horizontal axis wind turbine blades

Influence of control system on aerodynamic characteristics and elastic deformation of horizontal axis wind turbine blades

Comparison of applied loads on horizontal axis wind turbine blades using an open-source software Qblade and CFD solver ANSYS-FLUENT

Comparison of applied loads on horizontal axis wind turbine blades using an open-source software Qblade and CFD solver ANSYS-FLUENT

Natural Frequency Transmissibility for Detection of Cracks in Horizontal Axis Wind Turbine Blades.

Defects on horizontal axis wind turbine blades are difficult to identify and monitor with conventional forms of non-destructive examination due to the blade's large size and limited accessibility during continuous operation. This article examines both strain and acceleration transmissibility as methods of continuous damage detection on wind turbine blades. A scaled 117 cm offshore wind turbine blade was first designed, 3D printed, and modelled numerically in ANSYS. Transverse cracks were deliberately introduced to the blade at 10 cm intervals along its leading edge. Subsequent changes in the transmissibility, relative to an undamaged baseline model, were measured using different variable combinations at the blade's first three natural frequencies. Experimental results indicated that strain transmissibility was able to locate a 1.0 cm defect at a range of 70-110 cm from the blade hub using the amplitudes of the first natural frequency of vibration. The numerical model was able to simulate the strain experimental results and was determined to be valid for future defect characterization. Acceleration transmissibility was unable to experimentally identify defects sized at 1.0 cm and below but was able to identify 1.0 cm sized defects numerically. It was concluded that transmissibility is viable for continuous damage detection on blades but that further research into other defect types and locations is required prior to conducting full-scale testing.

Experimental Validation of a Passive-Adaptive Slat Concept and Characterization under Sinusoidal Fluctuations in the Angle of Attack

This article presents an experimental investigation of a passive-adaptive slat concept, an aerodynamic control mechanism aimed at avoiding separation in the inwards region of a horizontal axis wind turbine blade. The passive-adaptive slat is designed to autonomously adjust its position due to the aerodynamic forces acting on it, without the need of any active control system or external power source. The slat opens when the angle of attack increases beyond a certain threshold so that stall is delayed and closes for smaller angles of attack to increase the lift-to-drag ratio of the airfoil. A thorough aerodynamic characterisation of the passive-adaptive slat is performed in the wind tunnel followed by testing it under different sinusoidal inflows generated by a 2D active grid. It is observed that the slat system is able to leverage the advantages of both a clean airfoil and an airfoil with a fixed slat. It has the capability of delaying stalls for higher angles of attack, as well as having higher lift-to-drag ratio for lower angles of attack. It is also observed that, for fluctuating inflow, the passive-adaptive slat is able to achieve similar mean lift values as an airfoil with fixed slat while showing significant reduction in the lift fluctuations.

Development and Testing of a High Performance Airfoil for Application in Small Horizontal Axis Wind Turbine Blades

Development and Testing of a High Performance Airfoil for Application in Small Horizontal Axis Wind Turbine Blades

A frost ice formation method of horizontal axis wind turbine blade based on polynomial fitting

In this paper, a new direct calculation method of frost ice shape on the blade surface of horizontal axis wind turbine is proposed. Using linear interpolation algorithm, the airfoil ice shape obtained by LEWICE 2D software or ice wind tunnel experiment was fitted with equidistant step length in the first and fourth quadrants and equidistant step length in the second and third quadrants. The key point coordinates of ice shapes on cross-sections along the span-wise were mapped into lagging and flapping surfaces through the mathematical dimension reduction, respectively. The polynomial fitting was used to deal with ice projection points of multiple sections in lagging and flapping surfaces, and then the blade’s frost ice shape was obtained. By calculating the sum of squared residuals of the polar diameter at the same polar angle, the errors between experimental and airfoil frost shape fitting methods, experimental and FENSAP, and blade frost shape formation methods and FENSAP were analyzed. The results show that the new method is in good agreement with the ice shape of FENSAP simulation results and experimental results. The residual sum of squares is small. This method makes the analysis of frost ice morphology of wind turbine blades do not need to consider interdisciplinary. The calculation process is simple and reliable.

A study on coupled edgewise and flapwise vibration modes of wind turbine blade

The coupled flapwise and edgewise vibrations of a horizontal axis wind turbine blade (HAWT) are discussed in this paper. Kinetic and potential energies of the blade are evaluated with consideration of the effects of gravity and aerodynamic forces. Hamilton’s principle is employed to develop the nonlinear coupled modal equations of the blade. The coupling between the first order edgewise and the first two order of flapwise modes is considered. This leads to three equations with nonlinear terms. Multiple-scales perturbation method is employed to solve these equations. Furthermore, the numerical values of structural specifications of National Renewable Energy Laboratory (NREL) 5-MW reference wind turbine blade are used, for example. It is shown that first edgewise and first flapwise vibrations are dominant, while second flapwise mode of vibration is less significant in the case of transient responses. Energy transfer between resonant modes is observed in both internal and combination resonances. The amplitude–frequency curves and phase diagrams during primary and combination resonances are obtained for the steady-state responses. Combination and primary resonances are further examined by considering various factors such as geometric nonlinearity and aerodynamic force.

Design optimization of three‐dimensional geometry of a micro horizontal axis wind turbine blade using the response surface method

AbstractThis study presents an aerodynamic design optimization of a micro micro‐horizontal‐axis wind turbine (HAWT). To obtain an optimal design, it is essential to understand the design parameters and select the responsible factors that affect the blade efficiency. The aim of this work is to redesign a 3D micro‐HAWT to improve aerodynamic performance, through improving the distribution of chord length and twist angle along the blade. Performance analysis and flow visualization of the initial design and the optimal design were carried out using CFD analyzer. In the blade optimization design, eight significant input parameters were selected, five to characterize the chord length distribution and three to represent the twist angle along the blade. To maximize the efficiency, design points that are created by Design of Experiment (DoE) are evaluated through (Multi‐Objective‐Genetic Algorithm) MOGA method. The results showed a reduction on the separation effect area on the optimal blade surface compared to the initial one. The use of response surface optimization (RSO), when combined with CFD simulation, has proven beneficial in selecting the optimal HAWT design. Finally, the open source software (Qblade) was used to investigate and to compare the performance of the initial and optimum design. An efficiency enhancement of approximately 3.6% is achieved at tip speed ration TSR = 3.4.

Enhancing the Efficiency of Horizontal Axis Wind Turbines Through Optimization of Blade Parameters

In this research, we delve into the promising potential of horizontal axis wind turbines to effectively meet the electricity needs of developing countries. By addressing the challenges posed by low Reynolds number airflow characteristics, we focus on specific airfoils—E471, S2055, and RG15—tailored for horizontal axis wind turbine blade optimization. Utilizing QBLADE software, we evaluate the lift coefficient, stall angle of attack, and lift‐to‐drag ratio coefficient efficiency of these airfoils across various thickness‐to‐camber ratios. The aerodynamic efficiency of the altered airfoils is assessed in terms of lift coefficient, drag coefficient, lift‐to‐drag ratio coefficient, and stall angle of attack at Reynolds number ranging from 50,000 to 500,000. The findings reveal that the optimized thickness‐to‐camber ratio results in peak lift‐to‐drag ratio coefficient values surpassing the reference airfoils across the Re range. These lift‐to‐drag ratio coefficient enhancements vary among airfoils and Re values. Furthermore, modifications to the E471, S2055, and RG15 airfoils increase the peak lift coefficient and stall angle of attack values across all Re ranges examined. The validation of results is achieved through comparison with experimental testing, solidifying the reliability of QBLADE software in predicting aerodynamic performance.

Optimal airfoil selection for small horizontal axis wind turbine blades: A multi-criteria approach

Over the last century, the growing demand for clean energy has emphasized wind energy as a promising solu-tion to address contemporary energy challenges. Within the realm of wind energy, the wind turbine plays a pivotal role in harnessing the kinetic energy of the wind and converting it into electrical power. Among the various components of the wind turbine system, turbine blades assume a critical role in capturing the wind's kinetic energy and converting it into rotational motion. Consequently, the design of wind turbine blades holds the utmost importance in determining the overall performance and efficiency of the entire wind turbine system. One essential aspect of blade design involves selecting an appropriate airfoil. Throughout history, numerous airfoil profiles have been developed for various applications. Notably, National Advisory Committee for Aeronautics (NACA) and National Renewable Energy Laboratory (NREL) airfoils have been tailored for aircraft and large-scale wind turbine blades, respectively. However, the quest for suitable airfoil types for small-scale wind turbine blades has been ongoing. This study delves into an examination of over 62 distinct NACA and NREL aerofoil types tailored for small horizontal-axis wind turbine blades. Employing specialized software, namely QBlade, specifically designed for modeling and simulating wind turbine blades, the study calculates key parameters such as power output, stress, deformation, and weight for each airfoil. Subsequently, based on the simulated data, the optimal airfoil is identified using the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) multi-criteria selection approach. This selection process takes into account simulation results pertaining to power output, stress, deformation, and weight. The decision-making process involving multiple criteria is facilitated using Excel and Python. The findings of this study reveal that among the 62 airfoil types under consideration, the NACA 0024, NACA 2424, and NACA 4424 airfoils emerge as the most suitable choices for small horizontal-axis wind turbine blades.

Improved Design For Horizontal Axis Wind Turbine Blades With Winglets

The horizontal axis wind turbine blades are modified to enhance the turbine's aerodynamic performance. The performance of the modified geometry was evaluated by comparing the lift, drag and torque findings to the same propeller with a straight leading edge. The symmetrical airfoil of NACA 0012 was chosen for the turbine blade profiles. The computational fluid dynamics (CFD) simulation was performed using the shear stress transport (SST) k-ω turbulence model to capture the vortical structures for the inlet wind speed of 20 m/s. From the simulation results, it has been shown that the four blades with winglets at 15° angle of attack (AoA) orientation turbine have demonstrated the highest aerodynamic performance. It produces the lowest aerodynamic drag and the most increased torque for turbine rotations, which, in return, carries many economic advantages such as energy savings, low impact on the environment, reduced maintenance requirements, and less noise.Keywords: Aerodynamics, CFD, drag, horizontal axis wind turbine, lift, winglets

Performance estimation of small‐scale horizontal axis wind turbine blade

AbstractThe extracted energy from the wind is mainly influenced by the geometry of the rotor blades. Determining the aerodynamic optimum blade shape is one of the main tasks of the wind turbine designer. In the current study, the mixed airfoil technique was employed by using “Blade‐Element‐Momentum” (BEM) and “Computational‐Fluid‐Dynamics” (CFD) analysis to predict the aerodynamic performance of a small‐scale horizontal axis wind turbine blade. The BEM was then run using the open‐source wind turbine design and performance computation program Q‐Blade. The numerical simulation is carried out by Ansys Fluent. Here, the k‐ω Shear Stress Transport (SST) model was used. The results were compared with existing experimental data on lift and drag coefficients at the optimal angle of attack. The results of the two approaches were compared for different tip speed ratio values and a good agreement between CFD and BEM results was found.

Designing, Solid Modeling and Stress Analysis of Horizontal Axis Wind Turbine Blade

Wind energy is one of the clean renewable forms of energy that can handle the existing global fossil fuel crisis. Wind energy is captured by Wind turbine which converts kinetic energy of the wind into the mechanical energy and then this energy is transformed into electrical energy. The objective of this study is to design a 5kW wind turbine blade which includes selection of the blade airfoil based on CL/CD ratio, linearization of geometric parameters of the blade, solid modeling of blade profile and estimation of tangential, thrust forces and total power of the designed blade with the selection of the best material.

Stress Characteristics of Horizontal-Axis Wind Turbine Blades under Dynamic Yaw

The dynamic yaw significantly affects the aerodynamic load distribution of wind turbines, and the aerodynamic load is one of the main influencing factors of wind turbine structural stress variation. Taking the NACA4415 horizontal axis wind turbine designed by the research group as the research object, the numerical simulation was used to analyze the distribution characteristics of blade stress, surface thrust coefficient, and the wind turbine power output under periodic dynamic yaw conditions. The results show that the blade stress, blade axial thrust, and wind turbine output power were presented as a cosine distribution with yaw fluctuations. The distribution trend of blade stress showed an increase followed by a decrease from the inside out along the span direction. In addition, due to the influence of dynamic yaw and aerodynamic loads, the stress values near the blade root exhibited significant fluctuations. With the increase in tip speed ratio, the stress values of dynamic windward yaw gradually exceeded those of leeward yaw. Within the range of a 10° to 30° yaw variation period, the stress value with positive yaw was larger than that with negative yaw, and the highest stress value occurred in the range of −5° to 15°. The results can be provided as a theoretical basis for the structural design and yaw control strategies of wind turbines, considering dynamic yaw operation.

Simultaneous aerodynamic and structural optimisation of a low-speed horizontal-axis wind turbine blade using metaheuristic algorithms

AbstractThis work presents a concurrent design and multi-objective optimisation framework of horizontal axis wind turbine blades, made of composite material, for low wind speed. The optimisation model aims to minimise the structural mass of the blade whilst simultaneously maximising the turbine power output, subjected to three constraints viz. blade tip deflection, and Tsai-Hill and von Mises criteria. The design variables are blade shape and details of the internal blade structure. The control points and polynomial interpolation technique were adopted to determine the blade shape while the airfoil types at blade sections remained fixed. The internal blade structure design variables include the thickness of ribs and spars and the carbon fibre thickness and orientations. The blade element momentum approach is utilised to calculate turbine power and structural loads, whereas a finite element method is employed for structural analysis. Twelve multi-objective metaheuristics algorithms are used to solve the proposed multi-objective optimisation problem while their performance is investigated. The results obtained show that the multi-objective cuckoo search algorithm is the most efficient method. This study is said to be the baseline for a future study on multi-objective optimisation which combines two design stages of the composite low-speed wind turbine blades.

Horizontal axis wind turbine blade (HAWT) analysis based on blade element momentum theory (BEM) for some cities in Nigeria

In this research, the blade element momentum (BEM) theory of a horizontal axis wind turbine (HAWT) blade with 1 kW power output has been analysed for one station across the six geopolitical zones. Twenty years wind speed data (2000 – 2020) obtained from Nigeria meteorological Agency (NIMET) Head quarter, Abuja. In an effort to optimally explore and utilize wind energy, an optimal design of wind turbine blade needs to be obtained. Therefore, a computational method to analysed and optimize the performance of the wind turbine blades needs to be developed. For that purpose, a computational method based on the Blade Element Momentum (BEM) theory is developed in this study. In this method, the blade of a wind turbine is divided into several elements and it is assumed that there is no aerodynamic interaction amongst the elements. Furthermore, this (BEM) method incorporated with equations from momentum and blade element theories to obtain equations which are useful in wind turbine blades design process. In this research a computed result for aerodynamic characteristics based on BEM theory shows that, Maiduguri Metropolis is suitable for surface wind electrification among the selected stations with an estimated maximum wind power of 1.774𝑘𝑊 at total lift to drag ratio (𝐹𝐿/𝐹𝐷) of 27.2674 and a mean relative velocity of 14.99m/s. There is an agreement with my findings and that of other researchers.