The Darrieus wind turbine: Proposal for a new performance prediction model based on CFD (original) (raw)
Related papers
Performance prediction of a horizontal axis wind turbine using BEM and CFD methods
MATEC Web of Conferences, 2016
In this study, a combination of CFD (Computational Fluid Dynamics) and BEM (Blade Element Momentum Method) methods are used to simulate the flow field around a wind turbine rotor with horizontal axis. The main objectives are to predict the aerodynamic performances such as forces and torque imposed on the rotor blades which are essential to its structure or design. This approach requires much less computing time and memory than three-dimensional simulation flow around the wind turbine rotor with simple CFD method. The flow is assumed unsteady, incompressible and fully turbulent. This work consists of two parts:-The Calculation of aerodynamic coefficients by the CFD method, using Ansys / Fluent software.-The Simulation of 3D flow field through the rotor of the wind turbine using the BEM method. The obtained results are in good agreement with the experimental measurements. This is an Open Access article distributed under the terms of the Creative Commons Attribution License 4.0, which permits distribution, and reproduction in any medium, provided the original work is properly cited.
Energies, 2019
Aerodynamics of the Darrieus wind turbine is an extremely complex issue requiring the use of very advanced numerical methods. Additional structural components of this device, such as, for example, a rotating shaft disturb the flow through the rotor significantly impairing its aerodynamic characteristics. The main purpose of the presented research is to validate the commonly-used unsteady Reynolds averaged Navier-Stokes (URANS) approach with the shear stress transport (SST) k-ω turbulence model based on the particle image velocimetry (PIV) studies of a two-bladed rotor operating at the moderate tip speed ratio of 4.5. In the present numerical studies, a two-dimensional turbine rotor with a diameter of 1 meter was considered. The following parameters were evaluated: instantaneous velocity fields; velocity profiles in the rotor shadow and aerodynamic blade loads. The obtained numerical results are comparable with the reference experimental results taken from the literature. The second purpose of this work was to examine the influence of the rotating rotor shaft/tower on the wind turbine performance. It has been proven that the cylindrical shaft reduces the power of the device by 2.5% in comparison with the non-shaft configuration.
Numerical Simulation on Aerodynamic Performance of a Three-Bladed Darrieus – H Wind Turbine 1
2016
The purpose of this research work is to investigate computationally the improvement of the performance of the vertical-axis Darrieus-H wind turbine.The simulations of the aerodynamic field around a four-bladed straight –axis wind turbine (VAWT) are presented for different values of the Tip Speed Ratio λ (TSR), λ = 1.5 to λ = 3. Six different pitch angles are considered with symmetrical airfoil NACA0015. The Reynolds-Averaged Navier–Stokes equations are completed by the Kώ SST turbulence model. Multiple Reference Frames (MRF) model capability of a computational fluid dynamics (CFD) solver is used to express the dimensionless form of power output of the wind turbine as a function of the wind freestream velocity and the rotor’s rotational speed. The results show that the optimized turbine experienced maximum power coefficient of 0.41 in tip speed ratio of 2.5 and in pitch angle 6° for CFD simulations. The experimental data from the literature and computational results were then compare...
The computational fluid dynamics performance analysis of horizontal axis wind turbine
International Journal of Power Electronics and Drive Systems (IJPEDS), 2019
Computational fluid dynamics (CFD) simulations were performed in the present study using ANSYS Fluent 18.0, a commercially available CFD package, to characterize the behaviour of the new HAWT. Static three-dimensional CFD simulations were conducted. The static torque characteristics of the turbine and the simplicity of design highlight its suitability for the GE 1.5xle turbine. The major factor for generating the power through the HAWT is the velocity of air and the position of the blade angle in the HAWT blade assembly. The paper presents the effect of The blade is 43.2 m length and starts with a cylindrical shape at the root then transitions to the airfoils S818, S825 and S826 for the root, body and tip respectively. This blade also has pitch to vary as a function of radius, giving it a twist and the pitch angle at the blade tip is 4 degrees. This blade was created to be similar in size to a GE 1.5xle turbine by Cornell University. In addition, note that to represent the blade being connected to a hub, the blade root is offset from the axis of rotation by 1 meter. The hub is not included in our model. The experimental analysis of GE 1.5xle turbine, so that possible the result of CFD analysis can be compared with theoretical calculations. CFD workbench of ANSYS is used to carry out the virtue simulation and testing. The software generated test results are validated through the experimental readings. Through this obtainable result will be in the means of maximum constant power generation from HAWT.
Performance of a model wind turbine
The performance of a 0.9m diameter model wind turbine using the NREL s826 airfoil profile has been investigated both experimentally and numerically. The geometry was laid out using Blade Element Momentum theory (BEM). The design was tested experimentally and gave a peak power coefficient of C P = 0.448 at the design tip speed ratio of λ = 6. It was found that the BEM had correctly predicted the power coefficient curve very well giving virtually identical results to the measurements, except when the turbine is operating in a deep stall mode. The thrust predicted was however consistently too low by a shift of the order of ∆C T ∼ 0.1. After the model tests had been undertaken, numerical calculations were performed by means of fully 3D CFD simulations using a k − ω turbulence model. The high resolution CFD predictions (using about 3.5 × 10 6 grid points) reproduced the model thrust coefficient almost perfectly. The predicted power coefficients were also very close to the measurements, but somewhat overestimated at high tip speed ratios. At the design tip speed ratio the CFD over-predicted the power coefficient by merely 2%.
International Journal of Low-Carbon Technologies
The power output of a straight-bladed H-rotor Darrieus vertical axis wind turbine (HDVAWT) is explored in this article. The comparisons are performed between the NACA0018 airfoil and a series of Kline Fogelman modified NACA0018 airfoils. The computational fluid dynamics findings are first cross-checked with the experimental data, and the computational processes are validated as a consequence. Then, in CATIA, 12 airfoils were constructed by modifying the step thickness, step placement and trailing edge form to get an efficient model for the wind turbine. The approved computational processes are applied to all 13 models, and the results are obtained. In comparison to the NACA 0018 airfoil, the KFm3 airfoil with 12% step thickness and a rectangular trailing edge demonstrated a 47% efficiency under 6.65 m/s wind velocity and a rotational velocity of 120 RPM. The KFm3 airfoil also performed better when tested at 80 and 162 RPMs. Thus, the final HDVAWT has been presented for real-time app...
Study of performance of h-rotor darrieus wind turbines
Journal of Engineering Research, 2021
Vertical Axis Wind Turbines (VAWTs) are mostly manufactured keeping in mind the site and conditions that the wind turbine would face. There is a need to know which type of VAWT would be optimal in the conditions present at the installation site. The major factors involved are blade profile, wind velocity and blade pitch angle. This study is undertaken to study these factors and their effects on influencing the efficiency of the VAWT. A model has been made of a Darrieus VAWT with H-rotor design and is analyzed using CFD. An Iso-surface mesh is made on the model with a cylindrical air-filled domain and a κ-ε turbulence model is applied to study the effects of the wind-and-turbine blade interaction. The domain inlet indicates wind velocity; outlet is set to zero atmospheric gauge pressure and the pressure distribution across the turbine blade wall is measured. The top bottom walls of the domain are not part of the interaction. The study shows that the NACA0012 blade profile fares bette...
Authorea
Wind energy is one of the clean, sustainable types of energy that can deal with the current worldwide non-renewable energy source emergency. Even though it adds to 2.5% of the worldwide power request, with depletion of petroleum derivative sources, extraction of wind energy must reach to a more prominent degree to meet the energy emergency and issue of contamination. Now, to improve the aerodynamic response of a wind turbine, the blade pitch control is an effective method, usually applied to large-scale wind turbines. The present work incorporates an investigation of the impact of varied pitch angles on the performance parameters of a horizontal axis wind turbine. CFD code Fluent has been used to perform the simulations. A total of eight pitch angles are considered in this investigation. In addition to it, a numerical investigation of S809 airfoil has been performed and validated by a series of benchmark data. The SST k-w turbulence model has been utilized. The steady-state simulation is performed around a HAWT blade using multiple reference frame. It is seen that torque increases with an increase in wind velocity and decreases with an increase in pitch angle. The optimum pitch angle is obtained for maximum power generation.
Energies, 2013
Three different horizontal axis wind turbine (HAWT) blade geometries with the same diameter of 0.72 m using the same NACA4418 airfoil profile have been investigated both experimentally and numerically. The first is an optimum (OPT) blade shape, obtained using improved blade element momentum (BEM) theory. A detailed description of the blade geometry is also given. The second is an untapered and optimum twist (UOT) blade with the same twist distributions as the OPT blade. The third blade is untapered and untwisted (UUT). Wind tunnel experiments were used to measure the power coefficients of these blades, and the results indicate that both the OPT and UOT blades perform with the same maximum power coefficient, C p = 0.428, but it is located at different tip speed ratio, λ = 4.92 for the OPT blade and λ = 4.32 for the UOT blade. The UUT blade has a maximum power coefficient of C p = 0.210 at λ = 3.86. After the tests, numerical simulations were performed using a full three-dimensional computational fluid dynamics (CFD) method using the k-ω SST turbulence model. It has been found that CFD predictions reproduce the most accurate model power coefficients. The good agreement between the measured and computed power coefficients of the three models strongly
Renewable and Sustainable Energy Reviews, 2016
Horizontal-axis wind turbines (HAWTs) are the primary devices used in the wind energy sector. Systems used to evaluate the design of turbine blades and generators are key to improve the performance of HAWTs. Analysis of aerodynamic performance in turbine blades focuses on wind speed, rotational speed, and tip speed ratios (TSRs). This paper reviews computational as well as experimental methods used to measure the aerodynamic performance of HAWT blades. Among the numerical methods, we examine classical blade element momentum (BEM) theory and the modified BEM as well as computational fluid dynamics (CFD) and the BEM-CFD mixed approach. We also discuss the current computational methods for investigating turbine wake flows. Among the experimental methods, we examine field testing and wind tunnel experiment including aerodynamic torque measurement and blockage effects. A comparison of numerical and experimental approaches can help to improve accuracy in the prediction of wind turbine performance and facilitate the design of HAWT blades.