scholarly journals A Validation Study of the Aerodynamic Behaviour of a Wind Turbine: Three-Dimensional Rotational Case

CFD letters ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1-12
Author(s):  
Khaoula Qaissi ◽  
Omer Elsayed ◽  
Mustapha Faqir ◽  
Elhachmi Essadiqi
Keyword(s):  
Experimental Data ◽  
Wind Turbine ◽  
Validation Study ◽  
Three Dimensional ◽  
Wind Speeds ◽  
Turbulent Inflow ◽  
Attached Flow ◽  
Computational Fluid Dynamics Cfd ◽  
Variable Wind ◽  
Separating Flows

Numerical modelling and simulation of a rotating, tapered, and twisted three-dimensional blade with turbulent inflow conditions and separating flows is a challenging case in Computational Fluid Dynamics (CFD). The numerical simulation of the fluid flow behaviour over a wind turbine blade is important for the design of efficient machines. This paper presents a numerical validation study using the experimental data collected by the National Renewable Energy Laboratory (NREL). All the simulations are performed on the sequence S of the extensive experimental sequences conducted at the NASA/Ames wind tunnel with constant RPM and variable wind speeds. The results show close agreement with the NREL UAE experimental data. The CFD model captures closely the totality of the defining quantities. The shaft torque is well-predicted pre-stall but under-predicted in the stall region. The three-dimensional flow and stall are well captured and demonstrated in this paper. Results show attached flow in the pre-stall region. The separation appears at a wind speed of 10 m/s near the blade root. For V>10m/s, the blade appears to experience a deep stall from root to tip.

Design and Analysis of Wind Turbine Blades: Winglet, Tubercle, and Slotted

2013 ◽  
Author(s):  
Alka Gupta ◽  
Abdulrahman Alsultan ◽  
R. S. Amano ◽  
Sourabh Kumar ◽  
Andrew D. Welsh
Keyword(s):  
Power Generation ◽  
Wind Turbine ◽  
Turbine Blade ◽  
Alternative Energy ◽  
Turbine Blades ◽  
Three Dimensional ◽  
Wind Turbine Blade ◽  
Wind Turbine Blades ◽  
Wind Speeds ◽  
Governing Factor

Energy is the heart of today’s civilization and the demand seems to be increasing with our growing population. Alternative energy solutions are the future of energy, whereas the fossil-based fuels are finite and deemed to become extinct. The design of the wind turbine blade is the main governing factor that affects power generation from the wind turbine. Different airfoils, angle of twist and blade dimensions are the parameters that control the efficiency of the wind turbine. This study is aimed at investigating the aerodynamic performance of the wind turbine blade. In the present paper, we discuss innovative blade designs using the NACA 4412 airfoil, comparing them with a straight swept blade. The wake region was measured in the lab with a straight blade. All the results with different designs of blades were compared for their performance. A complete three-dimensional computational analysis was carried out to compare the power generation in each case for different wind speeds. It was found from the numerical analysis that the slotted blade yielded the most power generation among the other blade designs.

A Study of Aerodynamics Force Evaluation of Horizontal Axis Wind Turbine (HAWT) Blade Using 2D and 3D Comparison

2015 ◽  
Author(s):  
Nazia Binte Munir ◽  
Kyoungsoo Lee ◽  
Ziaul Huque ◽  
Raghava R. Kommalapati
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
Computational Fluid Dynamics ◽  
Wind Turbine ◽  
Blade Surface ◽  
Aerodynamic Forces ◽  
Horizontal Axis Wind Turbine ◽  
Computational Fluid Dynamics Cfd ◽  
Experimental Values ◽  
Nrel Phase Vi

The main purpose of the paper is to use Computational Fluid Dynamics (CFD) in 3-D analysis of aerodynamic forces of a Horizontal Axis Wind Turbine (HAWT) blade and compare the 3-D results with the 2-D experimental results. The National Renewable Energy Laboratory (NREL) Phase VI wind blade profile is used as a model for the analysis. The results are compared with the experimental data obtained by NREL at NASA Ames Research Center for the NREL Phase VI wind turbine blade. The aerodynamic forces are evaluated using 3-D Computational Fluid Dynamics (CFD) simulation. The commercial ANSYS CFX and parameterized 3-D CAD model of NREL Phase VI are used for the analysis. The Shear Stress Transport (SST) Gamma-Theta turbulence model and 0-degree yaw angle condition are adopted for CFD analysis. For the case study seven varying wind speeds (5 m/s, 7 m/s, 10 m/s, 13 m/s, 15 m/s, 20 m/s, 25 m/s) with constant blade rotational speed (72 rpm) are considered. To evaluate the 3-D aerodynamic effect sectional pressure coefficient (Cp) and integrated forces about primary axis such as normal, tangential, thrust and torque are evaluated for each of the seven wind speed cases and compared with the NREL experimental values. The numerical difference of values on wind blade surface between this study and 3-D results of NREL wind tunnel test are found negligible. The paper represents an important comparison between the 3-D lift & drag coefficient with the NREL 2-D experimental data. The results shows that though the current study is in good agreement with NREL 3-D experimental values there is large deviation between the NREL 2-D experimental data and current 3-D study which suggests that in case of 3-D analysis of aerodynamic force of blade surface it is better to use NREL 3-D values instead of 2-D experimental values.

A Study of Wind Turbine Wakes in Complex Terrain Through RANS Simulation and SCADA Data

2018 ◽  
Vol 140 (3) ◽  
Author(s):  
Davide Astolfi ◽  
Francesco Castellani ◽  
Ludovico Terzi
Keyword(s):  
Wind Turbine ◽  
Complex Terrain ◽  
Lateral Displacement ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Test Case ◽  
Cfd Simulations ◽  
Relevant Role ◽  
Computational Fluid Dynamics Cfd

This work deals with wind turbine wakes in complex terrain. The test case is a cluster of four 2.3 MW wind turbines, sited in a very complex terrain. Their performances are studied through supervisory control and data acquisition (SCADA) data, suggesting a relevant role of the terrain in distorting the wake of the upstream turbines. The experimental evidences stimulate a deeper comprehension through numerical modeling: computational fluid dynamics (CFD) simulations are run, using the Reynolds-averaged Navier–Stokes (RANS) formulation. A novel way of elaborating the output of the simulations is proposed, providing metrics for quantifying the three-dimensional (3D) evolution of the wake. The main outcome of the numerical analysis is that the terrain distorts the wind flow so that the wake profile is severely asymmetric with respect to the lateral displacement. Further, the role of orography singularities is highlighted in dividing the wake front, thus inducing faster wake recovery with respect to flat terrain. This interpretation is confirmed by SCADA data analysis.

Two-Phase CFD of Channel Boiling for Boiling Transition Problems

2014 ◽  
Author(s):  
Antonin Povolny ◽  
Martin Cuhra
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
First Principles ◽  
Flow Behavior ◽  
Three Dimensional ◽  
Two Phase ◽  
General Ability ◽  
Computational Fluid Dynamics Cfd ◽  
Cfd Method ◽  
Traditional Approaches

In order to ensure safety of nuclear installations, thermohydraulics has developed many ways how to predict the behavior of coolant in a heated boiling channel. Accuracy of these predictions can be improved using three-dimensional Computational Fluid Dynamics (CFD) method, which is based on first principles of fluid mechanics. Even though when using CFD, there is a struggle between the accuracy and low computation costs, in many cases CFD can provide feasible improvement of accuracy compared to more traditional approaches. In this research, the focus is set on channel boiling problems, especially those associated with boiling transitions. The phenomenon of critical heat flux (CHF) is investigated using two-phase CFD computation and is compared to experimental data. There is also comparison with other computation methods. When experiment provides some set of data, CFD calculation provides description of the whole flow behavior that provides significantly more information and is of great value during the design process when it gives the understanding of undergoing effects. Besides CHF, general ability of CFD to predict changes in boiling patterns in two-phase channel boiling flows is discussed.

scholarly journals Assessment of Two-Equation Turbulence Models and Validation of the Performance Characteristics of an Experimental Wind Turbine by CFD

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Ece Sagol ◽  
Marcelo Reggio ◽  
Adrian Ilinca
Keyword(s):  
Experimental Data ◽  
Flow Field ◽  
Wind Turbine ◽  
Flow Simulation ◽  
Turbulence Models ◽  
Bending Moment ◽  
Mesh Size ◽  
Turbine Rotor ◽  
Cross Sectional ◽  
Wind Speeds

The very first step in the simulation of ice accretion on a wind turbine blade is the accurate prediction of the flow field around it and the performance of the turbine rotor. The paper addresses this prediction using RANS equations with a proper turbulence model. The numerical computation is performed using a commercial CFD code, and the results are validated using experimental data for the 3D flow field around the NREL Phase VI HAWT rotor. For the flow simulation, a rotating reference frame method, which calculates the flow properties as time-averaged quantities, has been used to reduce the time spent on the analysis. A basic grid convergence study is carried out to select the adequate mesh size. The two-equation turbulence models available in ANSYS FLUENT are compared for a 7 m/s wind speed, and the one that best represents the flow features is then used to determine moments on the turbine rotor at five wind speeds (7 m/s, 10 m/s, 15 m/s, 20 m/s, and 25 m/s). The results are validated against experimental data, in terms of shaft torque, bending moment, and pressure coefficients at certain spanwise locations. Streamlines over the cross-sectional airfoils have also been provided for the stall speed to illustrate the separation locations. In general, results have shown good agreement with the experimental data for prestall speeds.

Effect of Inflow Conditions on Wind Turbine Blade Performance

2013 ◽  
Author(s):  
Kiran Kumar ◽  
Sudhakar Piragalathalwar ◽  
Jitendra Bijlani ◽  
Jesper Madsen
Keyword(s):  
Wind Turbine ◽  
Flow Characteristics ◽  
Design Basis ◽  
Turbulent Inflow ◽  
Engineering Models ◽  
Wind Tunnel Data ◽  
Computational Fluid Dynamics Cfd ◽  
And Performance ◽  
Turbine Design ◽  
Inflow Conditions

One important uncertainty still associated with the design and operation of wind turbines is the response and performance characteristics for the atmospheric inflow conditions. A very important issue in wind turbine design is the validity of the models that are used in the design process, the models used in Computational Fluid Dynamics (CFD) or the aerodynamic simulations. The aerodynamic part of the design basis has been restricted to non-shear turbulent inflow conditions. Therefore, measured detailed flow characteristics on a rotor in natural, turbulent flow environment are needed to be compared with 2D/3D CFD, wind tunnel data and other aerodynamic models. This will improve the prediction of the wind turbine response, but also represent a unique validation basis for 3D CFD computations and aerodynamic engineering models. The overall objective is to validate the CFD prediction with the field measurement.

Unsteady Propulsor Force Prediction for Spatially and Temporally Varying Inflow

2002 ◽  
Author(s):  
Stephen A. Huyer ◽  
Stephen R. Snarski
Keyword(s):  
Experimental Data ◽  
Three Dimensional ◽  
Axial Direction ◽  
Time Varying ◽  
Massachusetts Institute Of Technology ◽  
Mean Flow ◽  
Turbulent Inflow ◽  
Turbulent Characteristics ◽  
Unsteady Force ◽  
Institute Of Technology

A method to compute unsteady propulsor forces for spatially and temporally varying inflows is presented. A propulsor flow prediction code, previously developed by the Massachusetts Institute of Technology, was modified and upgraded to account for time varying inflow and multiple blade rotations. The original code utilizes lifting surface theory and discretizes the propulsor surface as boundary elements to compute the unsteady potential flow. Experimental data characterizing the full unsteady, three-dimensional turbulent inflow to a Swirl-Induced Stator Upstream of Propulsor (SISUP) propulsor, were used as inflow boundary conditions. Experimental data recorded the periodic velocity fluctuations due to the stator wakes as well as the broadband turbulent characteristics of the inflow. Blade force, integrated shaft force, and blade pressure are computed based on the experimental inflow. The effect of periodic variations in the inflow was examined to determine the effect on unsteady blade forces. For these cases, the time mean experimental effective inflow is used and a fluctuating component is added for flow in the axial direction. This may be viewed as an effectively fluctuating freestream. Comparisons of unsteady force and radiated noise are then made with the baseline mean flow case to gauge the time-varying effects. Fluctuating velocity dramatically altered the force spectra even at frequencies different from the velocity fluctuation frequency. This modified algorithm can now be utilized to examine a wider set of time-dependent propulsor flow problems and to calculate the associated performance due to these unsteady flows.

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