Wind Turbine Aerodynamic Performance Research Articles

A review of the state-of-the-art in aerodynamic performance of horizontal axis wind turbine

The paper presents the state-of-the-art in aerodynamic performance of the modern horizontal axis wind turbine. The study examines the different complexities involved with wind turbine blade aerodynamic performance in open atmosphere and turbine wakes, and highlights the issues which require further investigations. Additionally, the latest concept of smart blades and frequently used wind turbine design analysis tools have also been discussed. The investigation made through this literature survey shows significant progress towards wind turbine aerodynamic performance improvements in general. However, still there are several parameters whose behavior and specific role in regulating the performance of the blades is yet to be elucidated clearly; in particular, the wind turbulence, rotational effects, coupled effect of turbulence and rotation, extreme wind events, formation and life time of the wakes.

Unsteady aerodynamics simulation of a full-scale horizontal axis wind turbine using CFD methodology

The aerodynamic performance of wind turbines is significantly influenced by the unsteady flow around the rotor blades. The research on unsteady aerodynamics for Horizontal Axis Wind Turbines (HAWTs) is still poorly understood because of the complex flow physics. In this study, the unsteady aerodynamic configuration of a full-scale HAWT is simulated with consideration of wind shear, tower shadow and yaw motion. The calculated wind turbine which contains tapered tower, rotor overhang and tilted rotor shaft is constructed by making reference of successfully commercial operated wind turbine designed by NEG Micon and Vestas. A validated CFD method is utilized to analyze unsteady aerodynamic characteristics which affect the performance on such a full-scale HAWT. The approach of sliding mesh is used to carefully deal with the interface between static and moving parts in the flow field. The annual average wind velocity and wind profile in the atmospheric border are applied as boundary conditions. Considering the effects of wind shear and tower shadow, the simulation results show that the each blade reaches its maximum and minimum aerodynamic loads almost at the same time during the rotation circle. The blade–tower interaction imposes great impact on the power output performance. The wind turbine produces yaw moment during the whole revolution and the maximum aerodynamic loads appear at the upwind azimuth in the yaw computation case.

Empirical and numerical analysis of small wind turbine aerodynamic performance at a plateau terrain in Kenya

Kenya's energy depends on fossil fuels and the country is yet to embrace alternative sources that are environmentally friendly. In this paper, empirical and computational approaches are presented to investigate aerodynamic performance of Small Wind Turbine (SWT) operation at arid rural Mwingi-Kitui plateau region, Kenya. We used empirical statistics to represent wind resource, and Computational Fluid Dynamics (CFD) to address SWT aerodynamic performance at the site. The numerical simulations, employing Transition Shear Stress Transport (SST) model and fully mesh resolved rotor, were performed and results obtained compared with empirical methods. From the Wind Power Density (WPD) values, 44.50–85.48 W/m2 between turbine hub heights 20 and 60 m, the site corresponds to wind class ≈1; hence unsuitable for grid-connected power generation. In addition, the numerical findings give useful insights to SWT aerodynamic performance with respect to empirical approach at a plateau terrain wind regime.

Airfoil Design for Vertical Axis Wind Turbine Operating at Variable Tip Speed Ratios

A new airfoil design method for H type vertical axis wind turbine is introduced in the present study. A novel indicator is defined to evaluate vertical axis wind turbine aerodynamic performance at variable tip speed ratios and selected as the airfoil design objective. A mathematic model describing the relationship between airfoil design variables and objective is presented for direct airfoil design on the basis of regression design theory. The aerodynamic performance simulation is conducted by computational fluid dynamics approach validated by a wind tunnel test in the study. Based on the newly developed mathematic model, a new airfoil is designed for a given wind turbine model under constant wind speed of 8 m/s. Meanwhile, the comparison of aerodynamic performance for newly designed airfoil and existing vertical axis wind turbine airfoils is studied. It has been demonstrated that, by the novel indicator, the rotor aerodynamic performance at variable tip speed ratios with the newly designed airfoil is 6.78% higher than the one with NACA0015 which is the airfoil widely used in commercial H type vertical axis wind turbine.

Effect of Leading Edge Radius and Blending Distance from Leading Edge on the Aerodynamic Performance of Small Wind Turbine Blade Airfoils

The aerodynamic performance of a wind turbine depends upon shape of blade profile blade airfoils. Today, small wind turbine industries are extensively focusing on blade performance, reliability, materials and cost. The wind turbine blade designers are required to give emphasis on accurate analysis of flows around the blade and loads on wind turbine blades. Low Reynolds number airfoils suited for small wind turbine applications must be designed to have a high degree of tolerance in avoiding high leading suction peaks and high adverse pressure gradients that lead to flow separation. This paper presents a study to investigate the effect of leading edge radius and leading edge blending on the aerodynamic performance of wind turbine airfoils. In the present work NACA 4412 airfoil is considered as base airfoils. In this work six modified airfoils having different new to the old ratio of leading edge radii are considered for performance analysis. The performance of these six profiles is compared with basic airfoil performance. In this paper, the effect of blending distance from leading edge of airfoil on aerodynamic performance is also determined. Different five blending distances from leading edge are analyzed and compared with basic profile. The performance analysis of airfoils is carried out using Blade Element Momentum. In the present analysis, chord length of airfoils and Reynolds number are kept constant.

Static Analysis of Transit Points and theReynolds Number Influence on the Blade of aWind Power Turbine as Two-Dimensional

Airfoil Aerodynamic of the wind power turbines blade is of paramount importance on aerodynamic performance of wind turbines. This research includes a cross section choose of an airfoil employed in wind power turbine blades in the country. Here, the cross-section of 660 kW turbine blade, launched by the Vestas Company in Iran, has been modeled. Airfoil geometry was produced using the software ANSYS WORKBENCH, and has been analyzed fluidly via the software ANSYS FLUENT 15 across the angles of attack -5 to 20 degrees and in the Reynolds digits of􀫙. 􀫝􀫜 × 􀫚􀫙􀫟and 􀫙. 􀫡􀫝 × 􀫚􀫙􀫟 along with applying Turbulent flow influence. The effects of Reynolds digits and increase of turbulence have been analyzed over the crossing points' situation. Furthermore, this part of turbine has been tested experimentally in Shiraz wind tunnel and the coefficients of lift, drag, and other properties have been studied in case

An airfoil parameterization method for the representation and optimization of wind turbine special airfoil

A new airfoil shape parameterization method is developed, which extended the Bezier curve to the generalized form with adjustable shape parameters. The local control parameters at airfoil leading and trailing edge regions are enhanced, where have significant effect on the aerodynamic performance of wind turbine. The results show this improved parameterization method has advantages in the fitting characteristics of geometry shape and aerodynamic performance comparing with other three common airfoil parameterization methods. The new parameterization method is then applied to airfoil shape optimization for wind turbine using Genetic Algorithm (GA), and the wind turbine special airfoil, DU93-W-210, is optimized to achieve the favorable Cl/Cd at specified flow conditions. The aerodynamic characteristic of the optimum airfoil is obtained by solving the RANS equations in computational fluid dynamics (CFD) method, and the optimization convergence curves show that the new parameterization method has good convergence rate in less number of generations comparing with other methods. It is concluded that the new method not only has well controllability and completeness in airfoil shape representation and provides more flexibility in expressing the airfoil geometry shape, but also is capable to find efficient and optimal wind turbine airfoil. Additionally, it is shown that a suitable parameterization method is helpful for improving the convergence rate of the optimization algorithm.

Based on the Research of Wind Turbine Vibration Performance and Aerodynamic Performance

Wind turbines is one of the most important components of the wind turbine, design for wind turbines with good wind turbines is the basis of high wind energy utilization coefficient and large economic benefits. Using the theory of Wilson pneumatic designed 100 W horizontal axis wind turbine, in the process of design and design parameters on the vibration performance correction. Finally on rotor vibration modal experiment and pneumatic external characteristic experiment, the experimental results show that the design of the wind turbine at low wind speed can meet the design of the wind energy utilization coefficient, and the wind machine to avoid the resonance region speed at run time, extend the life of the rotor, so as to reduce the design cost.

Numerical investigations on the aerodynamic performance of wind turbine: Downwind versus upwind configuration

Although the upwind configuration is more popular in the field of wind energy, the downwind one is a promising type for the offshore wind energy due to its special advantages. Different configurations have different aerodynamic performance and it is important to predict the performance of both downwind and upwind configurations accurately for designing and developing more reliable wind turbines. In this paper, a numerical investigation on the aerodynamic performance of National Renewable Energy Laboratory (NREL) phase VI wind turbine in downwind and upwind configurations is presented. The open source toolbox OpenFOAM coupled with arbitrary mesh interface (AMI) method is applied to tackle rotating problems of wind turbines. Two 3D numerical models of NREL phase VI wind turbine with downwind and upwind configurations under four typical working conditions of incoming wind velocities are set up for the study of different unsteady characteristics of the downwind and upwind configurations, respectively. Numerical results of wake vortex structure, time histories of thrust, pressure distribution on the blade and limiting streamlines which can be used to identify points of separation in a 3D flow are presented. It can be concluded that thrust reduction due to blade-tower interaction is small for upwind wind turbines but relatively large for downwind wind turbines and attention should be paid to the vibration at a certain frequency induced by the cyclic reduction for both configurations. The results and conclusions are helpful to analyze the different aerodynamic performance of wind turbines between downwind and upwind configurations, providing useful references for practical design of wind turbine.

Aerodynamic Characteristics of Asymmetric Airfoils Blade Small Vertical Axis Wind Turbines

In this paper, using sliding mesh model, the numerical simulation of small vertical axis wind turbine aerodynamic performance was studied with FLUENT software. Got change rule of four same thickness and different camber‘s NACA series asymmetrical airfoil moment coefficient of the wind turbine and wind power machine with the tip speed ratio. Wind turbine benchmark blade around the flow field was studied. Research shows that within a certain range, small vertical axis wind turbine aerodynamic performance be promoted if the airfoil relative thickness increases. In the case of large attack angle, the wind turbine blade is easy to be separated. It provides a theoretical reference for optimal design of a small vertical axis wind turbine.

Stochastic performance evaluation of horizontal axis wind turbine blades using non-deterministic CFD simulations

In this paper, non-deterministic CFD (computational fluid dynamics) simulations have been performed to investigate the uncertain effects of stochastic boundary conditions on the aerodynamic performance of wind turbines. A NIPRC (non-intrusive probabilistic collocation) method is employed, which is coupled with a commercial flow solver. A 2D (two-dimensional) airfoil case is used to validate the non-deterministic simulation, where the angle of attack is considered as an uncertain parameter in a Gaussian distribution. The simulation results are compared with Monte Carlo simulation results. Based on the validation, non-deterministic CFD simulations were performed on a 3D (three-dimensional) wind turbine blades case, where the wind speed is considered as an uncertain parameter. The discussions mainly focus on the total performance variations and the uncertainty propagation in the fluid field. The simulation results show that the input uncertainty of the inlet velocity results in a high variation zone in the pressure distribution near the blade root, and which decreases from the root to the tip. With the wind speed increases, flow separation is observed. The separation vortex regions correspond to the maximum variation area, and the maximum variation extends to the trailing edge even to the whole suction side.

Prediction of the wind turbine performance by using BEM with airfoil data extracted from CFD

Blade element momentum (BEM) theory with airfoil data is a widely used technique for prediction of wind turbine aerodynamic performance, but the reliability of the airfoil data is an important factor for the prediction accuracy of aerodynamic loads and power. The airfoil characteristics used in BEM codes are mostly based on 2D wind tunnel measurements of airfoils with constant span. Due to 3D effects, a BEM code using airfoil data obtained directly from 2D wind tunnel measurements will not yield the correct loading and power. As a consequence, 2D airfoil characteristics have to be corrected before they can be used in a BEM code. In this article, we consider the MEXICO (Model EXperiments In Controlled cOnditions) rotor where airfoil data are extracted from CFD (Computational Fluid Dynamics) results. The azimuthally averaged velocity is used as the sectional velocity to define the angle of attack and the coefficient of lift and drag is determined by the forces on the blade. The extracted airfoil data are put into a BEM code without further corrections, and the calculated axial and tangential forces are compared to both computations using BEM with Shen's tip loss correction model and experimental data. The comparisons show that the recalculated forces by using airfoil data extracted from CFD have good agreements with the experiment.

Numerical Simulation of Vertical Axis Wind Turbine Blade Airfoil Performance

Research of blade airfoil aerodynamic characteristics is an important foundation for the vertical axis wind turbine aerodynamic design and performance analysis. CFD simulation software has been applied in this paper. Representative lift-type vertical axis wind turbine airfoil NACA0014, NACA2414, NACA4414, NACA6414, NACA8414 's aerodynamic simulation have been studied. Camber airfoil relative with the change in to the flow velocity is analyzed. At different angles of attack effect on the aerodynamic performance of wind turbines, variation of parameters for airfoil aerodynamic had been analyzed. It will help the optimal design of airfoils for vertical axis wind turbines.

A Comparison of Coarse-resolution Numerical Simulation with Experimental Measurements of Wind Turbine Aerodynamic Performance

Coarse-resolution computational fluid dynamics simulations using the unsteady Delayed-Detached-Eddy simulation (DDES) and the steady Reynolds-Averaged Navier-Stokes (RANS) methodologies were conducted to predict the aerodynamic performance of the Fortis Montana 5.8-kW horizontal-axis wind turbine (HAWT). The turbulence models used for the closure of the DDES and RANS methodologies were the one-equation Spalart-Allmaras model and the two-equation shear stress transport k − ω model, respectively. To assess and validate the predictive performance of these two simulation strategies conducted with coarse-resolution computational grids, experimental measurements of the Fortis Montana 5.8-kW HAWT were conducted at the 9 m × 9 m National Research Council Canada wind tunnel. Results of a detailed comparison between the wind tunnel experimental measurements and the model predictions are presented. It was found that predictions of the power curve using the DDES methodology yielded good conformance with the associated experimental measurements. Furthermore, it was found that the RANS method fails to capture the correct power output at moderate and high tip speed ratios. It is concluded that accuracy in a wind turbine power curve prediction using the relatively coarse mesh in this study is probably satisfactory for most real-world industrial and engineering applications.

Effect of moment of inertia to H type vertical axis wind turbine aerodynamic performance

The main aerodynamic performances (out power out power coefficient torque torque coefficient and so on) of H type Vertical Axis wind Turbine (H-VAWT) which is rotating machinery will be impacted by moment of inertia. This article will use NACA0018 airfoil profile to analyze that moment of inertia through impact performance of H type VAWT by utilizing program of Matlab and theory of Double-Multiple Streamtube. The results showed that the max out power coefficient was barely impacted when moment of inertia is changed in a small area,but the lesser moment of inertia's VAWT needs a stronger wind velocity to obtain the max out power. The lesser moment of inertia's VAWT has a big out power coefficient, torque coefficient and out power before it gets to the point of max out power coefficient. Out power coefficient, torque and torque coefficient will obviously change with wind velocity increased for VAWT of the lesser moment of inertia.

Analysis on Aerodynamic Performance of Horizontal Axis Wind Turbine Based on Nonlinear Wake Model

A computational method based on nonlinear wake model was established for horizontal axis wind turbines aerodynamic performance prediction. This method makes use of finite difference method to solve the integral differential equation of the model, the induced velocity of wake vortex can be calculated from equations and compared with the induced velocity of wake vortex in linear model. The comparison between the calculated results of wind turbine under axis flow condition, including tip vortex geometry and aerodynamic performance, and available experimental data shows that this method is suitable for wind turbine aerodynamic performance analysis. Finally, a series of numerical calculations were made to investigate the change of wake geometry and aerodynamic performance of the wind turbine when yawing and pitch angle increasing, which provide foundations for aerodynamic optimization design of horizontal axis wind turbines.

Numerical Simulation of Influence with Surface Contamination on Aerodynamic Performance of Dedicated Wind Turbine Airfoil

A Numerical simulation on the influence of airfoil surface contamination on the aerodynamic performance of wind turbines was performed. It chose the dedicated wind turbine airfoil as the research object. The k-ω Shear Stress Transmission (SST) turbulence model was selected for CFD calculation. The roughness height which arranged evenly on the airfoil was changed from 0.03mm to 2.0mm to obtain the sensitive roughness. The airfoil was divided into 18 sections for analyzing the effect on the lift & the drag coefficient, due to various locations of sensitive roughness. By comparing the result computed by XFOIL and CFD calculation, it can be known this airfoils sensitive locations in suction surface and pressure surface. The sensitive locations in suction surface were 53% and 92% from the chord line towards the leading edge, while 44% and 88% in pressure surface. The sensitive roughness in sensitive locations delayed the location of the transition point.

Horizontal Axis Wind Turbine Numerical Simulation of Two Dimensional Angle of Attack

wind power is the most effective form of wind energy utilization, modern large-scale wind turbine with horizontal axis wind mainly. Horizontal axis wind turbine aerodynamic performance calculation of the wind turbine aerodynamics research hot spot, is a wind turbine aerodynamic optimization design and calculation of critical load. Horizontal axis wind turbine airfoil aerodynamic performance of the wind turbine operation characteristics and life plays a decisive role". Using Fluent software on the horizontal axis wind turbine numerical simulation, analysis of the United States of America S809NREL airfoil aerodynamic characteristics of different angles of attack numerical simulation, analyzes the different angles of attack in the vicinity of the pressure, velocity distribution. By solving the two-dimensional unsteady, compressible N-S equations for the calculation of wind turbine airfoil S809used the characteristics of flow around. N-S equation in body-fitted coordinate system is given, with the Poisson equation method to generate the C grid.

Velocity interference in the rear rotor of a counter-rotating wind turbine

A counter-rotating wind turbine having two rotors rotating in opposite directions on the same axis is proposed to improve the aerodynamic performance of a wind turbine. In order to predict the aerodynamic performance of the counter-rotating wind turbine, the inflow interference in its rear rotor by the wake of the front rotor needs to be considered because the rear rotor operates inside the wake of the front rotor. In the previous research, the rear rotor was assumed to operate inside the fully developed stream tube of the front rotor to define the inflow condition on the rear rotor. In this study, to consider simultaneously the aerodynamic interaction between the two rotors of the counter-rotating wind turbine without any assumption on the inflow velocity of the rear rotor, an aerodynamic analysis of the counter-rotating wind turbine was carried out by using a free-wake vortex lattice method. The power coefficient and the wake geometry of the counter-rotating wind turbine were compared with those of a single rotor wind turbine, and the induction factors on the rear rotor were compared with that from the BEMT, assuming that the rear rotor operated inside the fully developed stream tube of the front rotor.

Study on the Affected Factors of Aerodynamic Performance of Vertical Axis Wind Turbine

The study of aerodynamic performance of vertical axis wind turbine is the basis of the VAWT design. The double disk multiple stream-tube, one of the numerical models for predicting the aerodynamic performance of the wind turbine, was used to calculate the aerodynamic performance of the Sandia DOE-17m VAWT. As shown in the comparison of the calculation results and the field test data, the DDMT model is efficient in predicting the aerodynamic performance. And then, a deep analysis of the inherent mechanisms that how the geometric parameters of wind turbine rotor like height to diameter ratio, solidity, chord and the number of blades affect the aerodynamic performance of turbine was made in the present work. The results will be the theoretical basis for the optimization of the design in aerodynamic performance of VAWT in the future work.