Correcting Inflow Measurements From Wind Turbines Using a Lifting-Surface Code

2000 ◽  
Vol 122 (4) ◽  
pp. 196-202 ◽  
Author(s):  
J. Whale ◽  
C. J. Fisichella ◽  
M. S. Selig
Keyword(s):  
Angle Of Attack ◽  
Three Dimensional ◽  
Correction Method ◽  
Local Flow ◽  
Flow Angle ◽  
Lifting Surface ◽  
Surface Code ◽  
Turbine Design ◽  
The Relationship ◽  
Blade Element

In order to provide accurate blade element data for wind turbine design codes, measured three-dimensional (3D) field data must be corrected in terms of the (sectional) angle of attack. A 3D Lifting-Surface Inflow Correction Method (LSIM) has been developed with the aid of a vortex-panel code in order to calculate the relationship between measured local flow angle and angle of attack. The results show the advantages of using the 3D LSIM correction over 2D correction methods, particularly at the inboard sections of the blade where the local flow is affected by post-stall effects and the influence of the blade root. [S0199-6231(00)00604-3]

Development of Pipe Flow Generators

2011 ◽  
Vol 233-235 ◽  
pp. 2432-2438
Author(s):  
Song Hao Wang ◽  
Ronald José Doblado Perez ◽  
Ronald García ◽  
Jia Cheng Chen
Keyword(s):  
Rapid Prototyping ◽  
Pipe Flow ◽  
Experimental Studies ◽  
Three Dimensional ◽  
Rotor Design ◽  
Modern Engineering ◽  
Different Types ◽  
Computational Fluid Dynamics Cfd ◽  
Turbine Design ◽  
The Relationship

This study aims to research and develop Pipe Flow Generators. The focus in this paper is on the rotor design for pipes of different sizes. Modern engineering tools such as Computational Fluid Dynamics (CFD) software and Rapid Prototyping technology are utilized to facilitate the numerical and experimental studies. The CFD numerical simulations consist of two and three-dimensional transient and steady analyses. These simulations were conducted to find the relationship between the flow rate, blade geometry and number of blades. During the experimentation process, Rapid Prototyping Technology (RP) was used to fabricate many different types of turbine geometries to test different impeller parameters. RPM and voltages where measured for each turbine design. The study leads to several important findings for better pipe flow generators design.

Yaw Aerodynamics Analyzed With Three Codes in Comparison With Experiment

2003 ◽  
Author(s):  
Helge Aagaard Madsen ◽  
Niels N. So̸rensen ◽  
Scott Schreck
Keyword(s):  
Element Model ◽  
Navier Stokes ◽  
Local Flow ◽  
Flow Angle ◽  
Comparison With Experiment ◽  
Actuator Disc ◽  
Grid Points ◽  
Yaw Angle ◽  
Angle Interval ◽  
Blade Element

Yaw aerodynamics were computed with three codes of different complexity; 1) The 3D Navier Stokes solver Ellipsys3D using 5–8 million grid points; 2) HAWC3D which is a 3D actuator disc model coupled to a blade element model and using 20–30.000 grid points and 3) HAWC, a finite element based aeroelastic code using The Blade Element Momentum (BEM) model for the aerodynamics. Simulations were performed for two experiments. The first is the field rotor measurements on a 100 kW turbine at Risoe where local flow angle (LFA) and local relative velocity (LRV) at one radial station have been measured in a yaw angle interval of ±60°. The other experiment is the NREL measurements on a 10 m rotor in the NASA Ames 80 ft × 120 ft wind tunnel. LFA were measured at five radial stations and data for the 45° yaw case were analyzed. The measured changes in LFA caused by the yawing were used as the main parameter in the comparison with the models. In general a good correlation was found comparing the Ellipsys3D results with the LFA measured on the NREL rotor whereas a systematic underestimation of the amplitude in LFA as function of azimuth was observed for the two other models. This could possibly be ascribed to upwash influence on the measured LFA.

Peak and Post-Peak Power Aerodynamics from Phase VI NASA Ames Wind Turbine Data

2005 ◽  
Vol 127 (2) ◽  
pp. 192-199 ◽  
Author(s):  
Brandon S. Gerber ◽  
James L. Tangler ◽  
Earl P. N. Duque ◽  
J. David Kocurek
Keyword(s):  
Performance Prediction ◽  
Peak Power ◽  
Tangential Force ◽  
Angle Of Attack ◽  
Three Dimensional ◽  
Wind Tunnel Test ◽  
Drag Coefficients ◽  
Force Coefficients ◽  
Lift And Drag ◽  
Blade Element

Constant speed/pitch rotor operation lacks adequate theory for predicting peak and post-peak power. The objective of this study was to identify and quantify how measured blade element performance characteristics from the Phase VI NASA Ames 24m×36m80ft×120ft wind tunnel test of a two-bladed, tapered, twisted rotor relate to the prediction of peak and post-peak rotor power. The performance prediction code, NREL’s Lifting Surface Prescribed Wake code (LSWT), was used to study the flow physics along the blade. Airfoil lift and drag coefficients along the blade were derived using the predicted angle of attack distribution from LSWT and Phase VI measured normal and tangential force coefficients. Through successive iterations, the local lift and drag coefficients were modified until agreement was achieved between the predicted and Phase VI measured normal and tangential force coefficients along the blade. This agreement corresponded to an LSWT angle of attack distribution and modified airfoil data table that reflected the measured three-dimensional aerodynamics. This effort identified five aerodynamic events important to the prediction of peak and post-peak power. The most intriguing event was a rapid increase in drag that corresponds with the occurrence of peak power. This is not currently modeled in engineering performance prediction methods.

scholarly journals Flow angle measurement of a yawed turbine and comparison to models

2017 ◽  
Author(s):  
Tyler Gallant ◽  
David A. Johnson
Keyword(s):  
Wind Turbine ◽  
Flow Direction ◽  
Angle Of Attack ◽  
Experimental Results ◽  
Pressure Probe ◽  
Flow Profile ◽  
Local Flow ◽  
Flow Angle ◽  
Angle Measurements ◽  
Probe Measurements

Abstract. The torque generated by a wind turbine blade is dependent on several parameters, one of which is the angle of attack. Several models for predicting the angle of attack in yawed conditions have been proposed in the literature, but there is a lack of experimental data to use for direct validation. To address this problem, experiments were conducted under controlled conditions at the University of Waterloo Wind Generation Research Facility using a 3.4 m diameter test turbine. A five-hole pressure probe was installed in a modular 3D printed blade and was used to measure the angle of attack, α, as a function of several parameters. Local flow angle measurements for all azimuthal angles were obtained at radial positions of r / R = 0.55 and 0.72 at tip speed ratios (λ) of 5.0, 3.6, and 3.1. The yaw offset of the turbine was varied from −15° to +15°. Span-wise flow angle measurements are presented for the r / R = 0.55 cases, and show the variation in radial flow direction throughout yawed rotation. Experimental results were compared directly to angle of attack values calculated using a model proposed by Morote in 2015. Modeled values were found to be in close agreement with the experimental results. The angle of attack was shown to vary cyclically in the yawed case while remaining mostly constant when aligned with the flow, as expected. These five-hole probe measurements were also used to characterise the upstream flow profile. Wind speeds determined using the five-hole probe measurements are presented and are in agreement with measurements obtained in the wind facility during testing. The quality of results indicates the potential of the developed instrument for wind turbine measurements.

Unsteady Linearized Lifting-Surface Theory in the Presence of a Free Surface

1987 ◽  
Vol 31 (03) ◽  
pp. 151-163
Author(s):  
J. Leclerc ◽  
P. Salaun
Keyword(s):  
Integral Equation ◽  
Free Surface ◽  
Unknown Function ◽  
Pressure Difference ◽  
Angle Of Attack ◽  
Three Dimensional ◽  
Thin Structures ◽  
Surface Theory ◽  
Lifting Surface ◽  
The Right

A new lifting-surface theory is developed for the computation of three-dimensional hydrodynamic pressures on thin structures in the presence of a free surface. Two interesting cases are treated: the steady case and the supercritical unsteady case. The theory is linearized and the problem is reduced to the solution of an integral equation where the unknown function is the pressure difference between the elements of the structure and the right-hand side the angle of attack. Forces and moments are presented in both the steady and unsteady cases. This theory allows the analysis of flutter and the study of steady drag and of the turn of ships.

scholarly journals Influence of Swirl Clocking on the Performance of Turbine Stage with Three-Dimensional Nozzle Guide Vane

Energies ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5503
Author(s):  
Shinyoung Jeon ◽  
Changmin Son ◽  
Jinuk Kim
Keyword(s):  
Guide Vane ◽  
Influencing Factor ◽  
Three Dimensional ◽  
Leading Edge ◽  
Aerodynamic Performance ◽  
Flow Angle ◽  
Nozzle Guide Vane ◽  
Nozzle Guide ◽  
Relationship Of ◽  
The Relationship

The effect of the swirl clocking on three-dimensional nozzle guide vane (NGV) is investigated using computational fluid dynamics. The research reports the loss characteristics of leaned and swept NGVs and the influence of swirl clocking. The three-dimensional NGVs are built by stacking the same 2D profile along different linear axes, characterized by different angles with respect to the normal or radial direction: ε = −12° ~ +12° for the leaned and γ = −5° ~ +10° for the swept airfoils. A total of 40 models are analyzed to study the effects of lean and sweep on aerodynamic performance. To investigate the influence of swirl clocking, the analysis cases include the center of the swirl that was positioned at the leading edge as well as the middle of the passage. The prediction results show that the relationship of the changes in mass flow rate and throat area are not monotonic. Further observation confirms the redistribution of loading and flow angle under different lean and sweep angles; thus, three-dimensional design is a key influencing factor on aerodynamic performance. In the presence of swirl clocking, NGV performance is changed significantly and the findings offer new insight and opportunities to improve three-dimensional NGV airfoil design.

Flow in a Rectangular Diffuser With Local Flow Detachment in the Corner Region

1983 ◽  
Vol 105 (2) ◽  
pp. 204-211 ◽  
Author(s):  
F. B. Gessner ◽  
Y. L. Chan
Keyword(s):  
Three Dimensional ◽  
Mean Velocity ◽  
Local Flow ◽  
Flow Angle ◽  
Corner Region ◽  
Streamwise Location ◽  
Angle Data ◽  
Oil Flow ◽  
Attached Flow ◽  
Corner Flows

An experimental study was conducted in order to examine the nature of flow within a high-inlet-aspect-ratio rectangular diffuser with locally detached flow in the corner region, but attached flow elsewhere in the diffuser. The results include flow visualization data corresponding to tuft and oil flow patterns observed on the diffuser walls and flow angle data taken in the immediate vicinity of the corner. Axial mean velocity distributions and local wall shear stress profiles are also presented. Analysis of the results provides new insight into the structure of separated, three-dimensional corner flows, wherein combined attached and detached flow conditions exist simultaneously at each streamwise location.

scholarly journals Analysis of Fan Stage Design Attributes for Boundary Layer Ingestion

2016 ◽  
Author(s):  
D. K. Hall ◽  
E. M. Greitzer ◽  
C. S. Tan
Keyword(s):  
Boundary Layer ◽  
Flow Analysis ◽  
Three Dimensional ◽  
Surface Geometry ◽  
Flow Distortion ◽  
Local Flow ◽  
Stage Design ◽  
Flow Angle ◽  
Inlet Distortion ◽  
Design Attributes

This paper describes a new conceptual framework for three-dimensional turbomachinery flow analysis and its use to assess fan stage attributes for mitigating adverse effects of inlet distortion due to boundary layer ingestion (BLI). A non-axisymmetric throughflow method has been developed to describe the fan flow field with inlet distortion. In this the turbomachinery is modeled using momentum and energy source distributions that are determined as a function of local flow conditions and a specified blade camber surface geometry. Comparison with higher-fidelity computational and experimental results shows that the method captures the principal flow redistribution and distortion transfer effects associated with BLI. Distortion response is assessed for a range of (i) rotor spanwise work profiles, (ii) rotor-stator spacings, and (iii) non-axisymmetric stator geometries. For the parameters examined, changes in axisymmetric design result in trades between rotor and stator distortions, or between different radial sections of a given blade row with marginal overall gain. Of the approaches examined, non-axisymmetric stator exit flow angle distributions were found to provide the greatest reduction in rotor flow distortion and thus may offer the most potential for mitigating decreases in performance due to BLI inlet distortion.

scholarly journals Radial Turbine Design for Solar Chimney Power Plants

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 674
Author(s):  
Paul Caicedo ◽  
David Wood ◽  
Craig Johansen
Keyword(s):  
Power Plants ◽  
Reference Frames ◽  
Three Dimensional ◽  
Discrete Ordinates ◽  
Large Area ◽  
Solar Chimney ◽  
Cfd Simulations ◽  
Radial Turbine ◽  
Design Changes ◽  
Turbine Design

Solar chimney power plants (SCPPs) collect air heated over a large area on the ground and exhaust it through a turbine or turbines located near the base of a tall chimney to produce renewable electricity. SCPP design in practice is likely to be specific to the site and of variable size, both of which require a purpose-built turbine. If SCPP turbines cannot be mass produced, unlike wind turbines, for example, they should be as cheap as possible to manufacture as their design changes. It is argued that a radial inflow turbine with blades made from metal sheets, or similar material, is likely to achieve this objective. This turbine type has not previously been considered for SCPPs. This article presents the design of a radial turbine to be placed hypothetically at the bottom of the Manzanares SCPP, the only large prototype to be built. Three-dimensional computational fluid dynamics (CFD) simulations were used to assess the turbine’s performance when installed in the SCPP. Multiple reference frames with the renormalization group k-ε turbulence model, and a discrete ordinates non-gray radiation model were used in the CFD simulations. Three radial turbines were designed and simulated. The largest power output was 77.7 kW at a shaft speed of 15 rpm for a solar radiation of 850 W/m2 which exceeds by more than 40 kW the original axial turbine used in Manzanares. Further, the efficiency of this turbine matches the highest efficiency of competing turbine designs in the literature.

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