WorldWideScience

Sample records for turbine aeroelasticity studies

  1. Proposed Wind Turbine Aeroelasticity Studies Using Helicopter Systems Analysis

    Science.gov (United States)

    Ladkany, Samaan G.

    1998-01-01

    Advanced systems for the analysis of rotary wing aeroelastic structures (helicopters) are being developed at NASA Ames by the Rotorcraft Aeromechanics Branch, ARA. The research has recently been extended to the study of wind turbines, used for electric power generation Wind turbines play an important role in Europe, Japan & many other countries because they are non polluting & use a renewable source of energy. European countries such as Holland, Norway & France have been the world leaders in the design & manufacture of wind turbines due to their historical experience of several centuries, in building complex wind mill structures, which were used in water pumping, grain grinding & for lumbering. Fossil fuel cost in Japan & in Europe is two to three times higher than in the USA due to very high import taxes. High fuel cost combined with substantial governmental subsidies, allow wind generated power to be competitive with the more traditional sources of power generation. In the USA, the use of wind energy has been limited mainly because power production from wind is twice as expensive as from other traditional sources. Studies conducted at the National Renewable Energy Laboratories (NREL) indicate that the main cost in the production of wind turbines is due to the materials & the labor intensive processes used in the construction of turbine structures. Thus, for the US to assume world leadership in wind power generation, new lightweight & consequently very flexible wind turbines, that could be economically mass produced, would have to be developed [4,5]. This effort, if successful, would result in great benefit to the US & the developing nations that suffer from overpopulation & a very high cost of energy.

  2. Evaluation study of a Navier-Stokes CFD aeroelastic model of wind turbine airfoils in classical flutter

    Energy Technology Data Exchange (ETDEWEB)

    Baxevanou, C.A.; Vlachos, N.S. [Department of Mechanical and Industrial Engineering, University of Thessaly, Athens Avenue, 38334 Volos (Greece); Chaviaropoulos, P.K. [Centre for Renewable Energy Sources, Pikermi Attikis (Greece); Voutsinas, S.G. [Department of Mechanical Engineering, National Technical University of Athens (Greece)

    2008-08-15

    This paper describes a new aeroelastic numerical model, which combines a Navier-Stokes CFD solver with an elastic model and two coupling schemes for the study of the aeroelastic behaviour of wind turbine blades undergoing classical flutter. The basic characteristics of the aerodynamic and elastic models are presented together with the coupling schemes. The present model is evaluated by comparing with previous numerical results and the corresponding linear analytical solutions. Consequently, a parametric study is carried out. Conclusions are drawn about the ability of the model to handle the aeroelastic behaviour of an airfoil and about the most appropriate coupling scheme in terms of predicting the modal damping and the flutter limiting point. The present study shows that the predictions are only slightly affected by the coupling or the space discretization scheme and mainly by the turbulence model used. (author)

  3. Research in Aeroelasticity EFP-2006[Wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    Bak, C.

    2007-07-15

    This report contains the results from the Energy Research Project 'Program for Research in Applied Aeroelasticity, EFP-2006' covering the period from 1. April 2006 to 31. March 2007. A summary of the main results from the project is given in the following. The aerodynamics for rotors incl. spinner and winglets were clarified and the needed premises for an optimal rotor were explained. Also, the influence of viscous effects on rotor blades was investigated and the results indicated a range of optimum tip speed ratios. The use of winglets for wind turbine rotor was investigated and it was found that they can be used successfully, but that downwind and short winglets are most efficient. Investigating a strategy for reduction of loads and vibrations at extreme wind speeds showed that there are considerably uncertainties in the numerical models and that the main concluding remark is that measurements on a real blade or a real turbine are needed to further conclude the investigation. In the study of flutter and other torsional vibrations of blades at large deflections, modeling and analysis of the dynamics of a hydraulic pitch system for a 5 MW wind turbine was carried out. It was shown that the compressibility of the hydraulic oil introduced a dynamic mode in the pitch bearing degree of freedom. Also, investigating flutter for blades at large deflections showed that the flutter limit for a 5MW blade was moved significantly compared to blades without large deflections. The influence of modeling nacelle components was investigated by developing a generalized method to interface dynamic systems to the aeroelastic program HAWC2 and by exemplify by modeling the nacelle of an aeroelastic wind turbine model in a more detailed way by including a single planet stage of a gearbox. This simplified gearbox model captures in essence the splitting of the driving torque from the rotor shaft to the frame of the nacelle and to the generator. Investigating the influence of wind

  4. Research in aeroelasticity[Wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    Bak, C.

    2006-05-15

    In the Energy Research Project 'Program for Research in Applied Aeroelasticity' (EFP2005), Risoe National Laboratory (Risoe) and the Technical University of Denmark (DTU) have applied and further developed the tools in the aeroelastic design complex. The main results from the project are: 1) Adding a winglet to a wind turbine blade for minimizing the induced drag of the blade led to the biggest increase in power of 1.4%. 2) Transient wind loads during pitch motion are determined using CFD. Compared to the NREL/NASA Ames test, reasonably good agreement is seen. 3) A general method was developed for the determination of 3D angle of attack for rotating blades from either measurements or numerical computations using CFD. 4) A model of the far wake behind wind turbines was developed for stability studies of the tip vortices in the far wake. 5) Investigating the blade root region showed that the power efficiency, CP, locally can be increased significantly beyond the Betz limit, but that the global CP for the rotor cannot exceed the Betz limit. When including tip losses and a minimum blade drag coefficient, a maximum rotor CP in the range of 0.51-0.52 was obtained. 6) A new airfoil family was designed and a 3D airfoil design tool was developed. Compared to the Risoe-B1 family, the new airfoil family showed similar or improved aerodynamic and structural characteristics. 7) Four different airfoils were analyzed to reveal the differences between 2D and 3D CFD. The major conclusions are the dependency of computational results to transition modelling, and the ability of 3D DES calculations to realistically simulate the turbulent wake of an airfoil in stall. 8) The capability of a theory for simulation of Gaussian turbulence driven gust events was demonstrated by emulating a violent shear gust event from a complex site. An asymptotic model for the PDF of the largest excursion from the mean level, during an arbitrary recurrence period, has been derived for a stochastic

  5. A wind turbine hybrid simulation framework considering aeroelastic effects

    Science.gov (United States)

    Song, Wei; Su, Weihua

    2015-04-01

    In performing an effective structural analysis for wind turbine, the simulation of turbine aerodynamic loads is of great importance. The interaction between the wake flow and the blades may impact turbine blades loading condition, energy yield and operational behavior. Direct experimental measurement of wind flow field and wind profiles around wind turbines is very helpful to support the wind turbine design. However, with the growth of the size of wind turbines for higher energy output, it is not convenient to obtain all the desired data in wind-tunnel and field tests. In this paper, firstly the modeling of dynamic responses of large-span wind turbine blades will consider nonlinear aeroelastic effects. A strain-based geometrically nonlinear beam formulation will be used for the basic structural dynamic modeling, which will be coupled with unsteady aerodynamic equations and rigid-body rotations of the rotor. Full wind turbines can be modeled by using the multi-connected beams. Then, a hybrid simulation experimental framework is proposed to potentially address this issue. The aerodynamic-dominant components, such as the turbine blades and rotor, are simulated as numerical components using the nonlinear aeroelastic model; while the turbine tower, where the collapse of failure may occur under high level of wind load, is simulated separately as the physical component. With the proposed framework, dynamic behavior of NREL's 5MW wind turbine blades will be studied and correlated with available numerical data. The current work will be the basis of the authors' further studies on flow control and hazard mitigation on wind turbine blades and towers.

  6. Aeroelastic optimization of MW wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    Hartvig Hansen, M.; Zahle, F.

    2011-12-15

    This report contains the results from the Energy Development and Demonstration Project ''Aeroelastic Optimization of MW wind turbine'' (AeroOpt). The project has had the following five Work Packages: 1. Geometric non-linear, anisotropic beam element for HAWC2. 2. Closed-loop eigenvalue analysis of controlled wind turbines. 3. Resonant wave excitation of lateral tower bending modes. 4. Development of next generation aerodynamic design tools. 5. Advanced design and verification of airfoils. The purposes of these Work Packages are briefly described in the Preface and a summary of the results are given in Section 2. Thereafter, the results from each Work Package are described in eight subsequent chapters. (Author)

  7. State of the art in wind turbine aerodynamics and aeroelasticity

    DEFF Research Database (Denmark)

    Hansen, Martin Otto Laver; Sørensen, Jens Nørkær; Voutsinas, S

    2006-01-01

    A comprehensive review of wind turbine aeroelasticity is given. The aerodynamic part starts with the simple aerodynamic Blade Element Momentum Method and ends with giving a review of the work done applying CFD on wind turbine rotors. In between is explained some methods of intermediate complexity...

  8. Aeroelastic stability analysis of a Darrieus wind turbine

    Energy Technology Data Exchange (ETDEWEB)

    Popelka, D.

    1982-02-01

    An aeroelastic stability analysis has been developed for predicting flutter instabilities on vertical axis wind turbines. The analytical model and mathematical formulation of the problem are described as well as the physical mechanism that creates flutter in Darrieus turbines. Theoretical results are compared with measured experimental data from flutter tests of the Sandia 2 Meter turbine. Based on this comparison, the analysis appears to be an adequate design evaluation tool.

  9. Gravo-Aeroelastic Scaling for Extreme-Scale Wind Turbines

    Energy Technology Data Exchange (ETDEWEB)

    Fingersh, Lee J [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Loth, Eric [University of Virginia; Kaminski, Meghan [University of Virginia; Qin, Chao [University of Virginia; Griffith, D. Todd [Sandia National Laboratories

    2017-06-09

    A scaling methodology is described in the present paper for extreme-scale wind turbines (rated at 10 MW or more) that allow their sub-scale turbines to capture their key blade dynamics and aeroelastic deflections. For extreme-scale turbines, such deflections and dynamics can be substantial and are primarily driven by centrifugal, thrust and gravity forces as well as the net torque. Each of these are in turn a function of various wind conditions, including turbulence levels that cause shear, veer, and gust loads. The 13.2 MW rated SNL100-03 rotor design, having a blade length of 100-meters, is herein scaled to the CART3 wind turbine at NREL using 25% geometric scaling and blade mass and wind speed scaled by gravo-aeroelastic constraints. In order to mimic the ultralight structure on the advanced concept extreme-scale design the scaling results indicate that the gravo-aeroelastically scaled blades for the CART3 are be three times lighter and 25% longer than the current CART3 blades. A benefit of this scaling approach is that the scaled wind speeds needed for testing are reduced (in this case by a factor of two), allowing testing under extreme gust conditions to be much more easily achieved. Most importantly, this scaling approach can investigate extreme-scale concepts including dynamic behaviors and aeroelastic deflections (including flutter) at an extremely small fraction of the full-scale cost.

  10. Optimization of wind turbine rotors - using advanced aerodynamic and aeroelastic models and numerical optimization

    Energy Technology Data Exchange (ETDEWEB)

    Doessing, M.

    2011-05-15

    During the last decades the annual energy produced by wind turbines has increased dramatically and wind turbines are now available in the 5MW range. Turbines in this range are constantly being developed and it is also being investigated whether turbines as large as 10-20MW are feasible. The design of very large machines introduces new problems in the practical design, and optimization tools are necessary. These must combine the dynamic effects of both aerodynamics and structure in an integrated optimization environment. This is referred to as aeroelastic optimization. The Risoe DTU optimization software HAWTOPT has been used in this project. The quasi-steady aerodynamic module have been improved with a corrected blade element momentum method. A structure module has also been developed which lays out the blade structural properties. This is done in a simplified way allowing fast conceptual design studies and with focus on the overall properties relevant for the aeroelastic properties. Aeroelastic simulations in the time domain were carried out using the aeroelastic code HAWC2. With these modules coupled to HAWTOPT, optimizations have been made. In parallel with the developments of the mentioned numerical modules, focus has been on analysis and a fundamental understanding of the key parameters in wind turbine design. This has resulted in insight and an effective design methodology is presented. Using the optimization environment a 5MW wind turbine rotor has been optimized for reduced fatigue loads due to apwise bending moments. Among other things this has indicated that airfoils for wind turbine blades should have a high lift coefficient. The design methodology proved to be stable and a help in the otherwise challenging task of numerical aeroelastic optimization. (Author)

  11. Development and Analysis of a Swept Blade Aeroelastic Model for a Small Wind Turbine (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Preus, R.; Damiani, R.; Lee, S.; Larwood, S.

    2014-06-01

    As part of the U.S. Department-of-Energy-funded Competitiveness Improvement Project, the National Renewable Energy Laboratory (NREL) developed new capabilities for aeroelastic modeling of precurved and preswept blades for small wind turbines. This presentation covers the quest for optimized rotors, computer-aided engineering tools, a case study, and summary of the results.

  12. Aeroelastic instability problems for wind turbines

    DEFF Research Database (Denmark)

    Hansen, Morten Hartvig

    2007-01-01

    This paper deals with the aeroelostic instabilities that have occurred and may still occur for modem commercial wind turbines: stall-induced vibrations for stall-turbines, and classical flutter for pitch-regulated turbines. A review of previous works is combined with derivations of analytical sta...... issues that represent unsolved aeroelostic instability problems for wind turbines. Copyright (c) 2007 John Wiley & Sons, Ltd.......This paper deals with the aeroelostic instabilities that have occurred and may still occur for modem commercial wind turbines: stall-induced vibrations for stall-turbines, and classical flutter for pitch-regulated turbines. A review of previous works is combined with derivations of analytical...... stability limits for typical blade sections that show the fundamental mechanisms of these instabilities. The risk of stall-induced vibrations is mainly related to blade airfoil characteristics, effective direction of blade vibrations and structural damping, whereas the blade tip speed, torsional blade...

  13. Design gridlines for integrated aeroelastic control of wind turbines - Task-12 report

    DEFF Research Database (Denmark)

    Mogensen, T.S.; Larsen, A.J.; Poulsen, N.K.

    The presented design guidelines for active aeroelastic control of PRVS wind turbines are derived by the partners of the project - Aeroelastic Stability and Control of Large Wind Turbines” (STABCON) partially funded by the European Commission (EC) under the contract NNK5-CT2002-00627. The objective...... of this successful long term research cooperation....

  14. The influence of turbulence on the aero-elastic instability of wind turbines

    DEFF Research Database (Denmark)

    Zhang, Zili; Nielsen, Søren R.K.

    2014-01-01

    calibrated to the NREL 5 MW baseline wind turbine. Aeroelastic stability of the wind turbine system has been evaluated for various values of the rated generator torque, the rated rotational speed of the rotor, the mean wind speed and the turbulence intensity. Critical turbulence intensity, at which the wind...... turbine shifts from a stable state into an instable state, is determined in different cases. Results show that turbulence intensity has significant influence on the aeroelastic stability of high-performance wind turbines operating close to stall, and the stability of the wind turbine might be changed due...

  15. Aeroelastic modal dynamics of wind turbines including anisotropic effects

    Energy Technology Data Exchange (ETDEWEB)

    Fisker Skjoldan, P.

    2011-03-15

    Several methods for aeroelastic modal analysis of a rotating wind turbine are developed and used to analyse the modal dynamics of two simplified models and a complex model in isotropic and anisotropic conditions. The Coleman transformation is used to enable extraction of the modal frequencies, damping, and periodic mode shapes of a rotating wind turbine by describing the rotor degrees of freedom in the inertial frame. This approach is valid only for an isotropic system. Anisotropic systems, e.g., with an unbalanced rotor or operating in wind shear, are treated with the general approaches of Floquet analysis or Hill's method which do not provide a unique reference frame for observing the modal frequency, to which any multiple of the rotor speed can be added. This indeterminacy is resolved by requiring that the periodic mode shape be as constant as possible in the inertial frame. The modal frequency is thus identified as the dominant frequency in the response of a pure excitation of the mode observed in the inertial frame. A modal analysis tool based directly on the complex aeroelastic wind turbine code BHawC is presented. It uses the Coleman approach in isotropic conditions and the computationally efficient implicit Floquet analysis in anisotropic conditions. The tool is validated against system identifications with the partial Floquet method on the nonlinear BHawC model of a 2.3 MW wind turbine. System identification results show that nonlinear effects on the 2.3 MW turbine in most cases are small, but indicate that the controller creates nonlinear damping. In isotropic conditions the periodic mode shape contains up to three harmonic components, but in anisotropic conditions it can contain an infinite number of harmonic components with frequencies that are multiples of the rotor speed. These harmonics appear in calculated frequency responses of the turbine. Extreme wind shear changes the modal damping when the flow is separated due to an interaction between

  16. The influence of turbulence on the aero-elastic instability of wind turbines

    DEFF Research Database (Denmark)

    Zhang, Zili; Nielsen, Søren R.K.

    2014-01-01

    Modern multi-megawatt wind turbines are designed with longer and slender blades using new composite materials and advanced fabrication methods. The trend towards lighter and more flexible blades may lead to aeroelastic instability of wind turbines under certain circumstances, thus resulting...... aerodynamic damping. A 13-degree-of-freedom (13-DOF) wind turbine model is developed using Euler-Lagrange equations, which includes the couplings of the tower-blade-drivetrain vibration, the quasi-static aeroelasticity and a collective pitch controller. Numerical simulations are carried out using data...... turbine shifts from a stable state into an instable state, is determined in different cases. Results show that turbulence intensity has significant influence on the aeroelastic stability of high-performance wind turbines operating close to stall, and the stability of the wind turbine might be changed due...

  17. Low-order aeroelastic models of wind turbines for controller design

    DEFF Research Database (Denmark)

    Sønderby, Ivan Bergquist

    Wind turbine controllers are used to optimize the performance of wind turbines such as to reduce power variations and fatigue and extreme loads on wind turbine components. Accurate tuning and design of modern controllers must be done using low-order models that accurately captures the aeroelastic...... response of the wind turbine. The purpose of this thesis is to investigate the necessary model complexity required in aeroelastic models used for controller design and to analyze and propose methods to design low-order aeroelastic wind turbine models that are suited for model-based control design...... stall using only few states. A set of reduced-order models obtained at various operating points are shown to be easily connected by interpolation and are thereby suited for gain-scheduling control design. A new method is proposed to reduce separately the number of structural and aerodynamic states...

  18. Effects of extreme wind shear on aeroelastic modal damping of wind turbines

    DEFF Research Database (Denmark)

    Skjoldan, P.F.; Hansen, Morten Hartvig

    2013-01-01

    Wind shear is an important contributor to fatigue loads on wind turbines. Because it causes an azimuthal variation in angle of attack, it can also affect aerodynamic damping. In this paper, a linearized model of a wind turbine, based on the nonlinear aeroelastic code BHawC, is used to investigate...

  19. Aeroelastic Optimization of a 10 MW Wind Turbine Blade with Active Trailing Edge Flaps

    DEFF Research Database (Denmark)

    Barlas, Athanasios; Tibaldi, Carlo; Zahle, Frederik

    2016-01-01

    This article presents the aeroelastic optimization of a 10MW wind turbine ‘smart blade’ equipped with active trailing edge flaps. The multi-disciplinary wind turbine analysis and optimization tool HawtOpt2 is utilized, which is based on the open-source framework Open-MDAO. The tool interfaces to ...

  20. Quick Method for Aeroelastic and Finite Element Modeling of Wind Turbine Blades

    DEFF Research Database (Denmark)

    Bennett, Jeffrey; Bitsche, Robert; Branner, Kim

    2014-01-01

    In this paper a quick method for modeling composite wind turbine blades is developed for aeroelastic simulations and finite element analyses. The method reduces the time to model a wind turbine blade by automating the creation of a shell finite element model and running it through a cross...... the user has two models of the same blade, one for performing a structural finite element model analysis and one for aeroelastic simulations. Here, the method is implemented and applied to reverse engineer a structural layup for the NREL 5MW reference blade. The model is verified by comparing natural...

  1. OC3 -- Benchmark Exercise of Aero-Elastic Offshore Wind Turbine Codes: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Passon, P.; Kuhn, M.; Butterfield, S.; Jonkman, J.; Camp, T.; Larsen, T. J.

    2007-08-01

    This paper introduces the work content and status of the first international investigation and verification of aero-elastic codes for offshore wind turbines as performed by the "Offshore Code Comparison Collaboration" (OC3) within the "IEA Wind Annex XXIII -- Subtask 2".

  2. Two methods for estimating aeroelastic damping of operational wind turbine modes from experiments

    DEFF Research Database (Denmark)

    Hansen, Morten Hartvig; Thomsen, Kenneth; Fuglsang, Peter

    2006-01-01

    The theory and results of two experimental methods for estimating the modal damping of a wind turbine during operation are presented. Estimations of the aeroelastic damping of the operational turbine modes (including the effects of the aerodynamic forces) give a quantitative view of the stability...... the deterministic excitation, and the modal frequencies and damping of the first tower and first edgewise whirling modes are extracted. Copyright © 2006 John Wiley & Sons, Ltd....

  3. Optimization of wind turbine rotors - using advanced aerodynamic and aeroelastic models and numerical optimization

    DEFF Research Database (Denmark)

    Døssing, Mads

    During the last decades the annual energy produced by wind turbines has increased dramatically and wind turbines are now available in the 5MW range. Turbines in this range are constantly being developed and it is also being investigated whether turbines as large as 10-20MW are feasible. The design...... numerical modules, focus has been on analysis and a fundamental understanding of the key parameters in wind turbine design. This has resulted in insight and an eective design methodology is presented. Using the optimization environment a 5MW wind turbine rotor has been optimized for reduced fatigue loads...... due to apwise bending moments. Among other things this has indicated that airfoils for wind turbine blades should have a high lift coecient. The design methodology proved to be stable and a help in the otherwise challenging task of numerical aeroelastic optimization....

  4. Implementation of the Actuator Cylinder Flow Model in the HAWC2 code for Aeroelastic Simulations on Vertical Axis Wind Turbines

    DEFF Research Database (Denmark)

    Aagaard Madsen, Helge; Larsen, Torben J.; Schmidt Paulsen, Uwe

    2013-01-01

    The paper presents the implementation of the Actuator Cylinder (AC) flow model in the HAWC2 aeroelastic code originally developed for simulation of Horizontal Axis Wind Turbine (HAWT) aeroelasticity. This is done within the DeepWind project where the main objective is to explore the competitivene...

  5. Numerical Simulations of the Aeroelastic Behavior of Large Horizontal-Axis Wind Turbines: The Drivetrain Case

    DEFF Research Database (Denmark)

    Gebhardt, Cristian; Veluri, Badrinath; Preidikman, Sergio

    2010-01-01

    loads and their evolution in the space and the time domains, considering multiple aerodynamic interactions among blades, wakes, hub, nacelle, support tower, ground and land–surface boundary layer. All these in combination affect substantially the total efficiency of the turbine. In addition, a flexible......In this work an aeroelastic model that describes the interaction between aerodynamics and drivetrain dynamics of a large horizontal–axis wind turbine is presented. Traditional designs for wind turbines are based on the output of specific aeroelastic simulation codes. The output of these codes gives...... implies that vibrations of these internal drive train components are not taken into account and, as a consequence, dynamic loads on these components cannot be simulated. In this effort an aerodynamical model based on the non–linear and unsteady vortex–lattice method is used to compute the aerodynamic...

  6. Fast Trailed Vorticity Modeling for Wind Turbine Aerodynamics and its Influence on Aeroelastic Stability

    DEFF Research Database (Denmark)

    Pirrung, Georg

    efficiency is increased. The model is validated against results from full rotor CFD and free wake panel code computations, which show that the model yields improved results in steady and unsteady simulations compared to unsteady BEM modeling. Especially the aerodynamic work due to prescribed in-plane and out......In this work, an aerodynamic model for the use in aeroelastic wind turbine codes is presented. It consists of a simplified lifting line model covering the induction due to the trailed vorticity in the near wake, a 2D shed vorticity model and a far wake model using the well known blade element...... momentum (BEM) theory. The model is an extension of unsteady BEM models, which provides a radial coupling of the aerodynamic sections through the trailed vorticity. The model is very fast and slows down aeroelastic wind turbine simulations by only few percent, compared to an unsteady BEM model. Compared...

  7. The aeroelasticity research project 2004[Wind turbines]; Forskning i aeroelasticitet EFP-2004

    Energy Technology Data Exchange (ETDEWEB)

    Bak, C.

    2005-05-01

    The report presents the results of the project ''Programme for Applied Aeroelasticity'', the Danish Energy Research Programme 2004. The main results are: 1) Based on an analysis of the NREL/NASA experiment with a wind turbine in a wind tunnel a new model is formulated for 3D corrections of profile data for aeroelastic codes. Use of the model on three rotors suggests that the load distribution is determined more correctly than in existing 3D models. 2) A near-wake model, originally developed for aerodynamic loads on helicopter rotors, is implemented for calculating dynamic induction on wind turbine rotors. The model has several advantages to the other normally used model BEM. 3) A detailed comparison of the aeroelastic models FLEX5 and HAWC shows that there are no model differences that can result in large differences in the calculated loads. The comparison shows that differences in the calculated loads are due to the use of the models. 4) A model for pitch-servo dynamics on a modern wind turbine is formed and implemented in HAWC2. The conclusion from analysis of the importance of the pitch-servo characteristics showed that coupling between structure/aerodynamics and pitch actuator may be of importance, especially for the loads on the actuator itself. Also large deflections are coupled to the pitch moment and thus also to torsion of the wing and wing bearing. 5) An un-linear stability analysis has been performed in which periodic loads are included and compared to a linear analysis used in HAWCStab. For a profile with near zero aerodynamic damping in one oscillation direction, the aerodynamic force in this direction depends mostly of the square on the profile's speed. The linear damping is changed only a little by the profile's forced oscillation. It is assumed that the present HAWCStab can predict the mean aeroelastic damping for turbines' oscillations in operation. (LN)

  8. Analysis of wind turbine aerodynamics and aeroelasticity using vortex-based methods

    DEFF Research Database (Denmark)

    Branlard, Emmanuel Simon Pierre

    Momentum analysis through Blade Element Momentum (BEM) and Computational Fluid Dynamics (CFD) are the two major paths commonly followed for wind turbine aerodynamic and aeroelastic research. Instead, the current PhD thesis focuses on the application of vortex-based methods. Vortex-based methods...... to be used in BEM implementations. The current thesis also presents the implementation of a vortex code to further investigate wind turbine aerodynamics. The code consists of both low-order and high-order formulations. The implementation features are described and illustrated through different validation...

  9. New aeroelastic studies for a morphing wing

    Directory of Open Access Journals (Sweden)

    Ruxandra Mihaela BOTEZ*

    2012-06-01

    Full Text Available For this study, the upper surface of a rectangular finite aspect ratio wing, with a laminar airfoil cross-section, was made of a carbon-Kevlar composite material flexible skin. This flexible skin was morphed by use of Shape Memory Alloy actuators for 35 test cases characterized by combinations of Mach numbers, Reynolds numbers and angles of attack. The Mach numbers varied from 0.2 to 0.3 and the angles of attack ranged between -1° and 2°. The optimized airfoils were determined by use of the CFD XFoil code. The purpose of this aeroelastic study was to determine the flutter conditions to be avoided during wind tunnel tests. These studies show that aeroelastic instabilities for the morphing configurations considered appeared at Mach number 0.55, which was higher than the wind tunnel Mach number limit speed of 0.3. The wind tunnel tests could thus be performed safely in the 6’×9’ wind tunnel at the Institute for Aerospace Research at the National Research Council Canada (IAR/NRC, where the new aeroelastic studies, applied on morphing wings, were validated.

  10. Aeroelastic modal dynamics of wind turbines including anisotropic effects

    DEFF Research Database (Denmark)

    Skjoldan, Peter Fisker

    and the computationally efficient implicit Floquet analysis in anisotropic conditions. The tool is validated against system identifications with the partial Floquet method on the nonlinear BHawC model of a 2.3 MW wind turbine. System identification results show that nonlinear effects on the 2.3 MW turbine in most cases....... These harmonics appear in calculated frequency responses of the turbine. Extreme wind shear changes the modal damping when the flow is separated due to an interaction between the periodic mode shape and the local aerodynamic damping influenced by a periodic variation in angle of attack....

  11. Aero-Elastic Optimization of a 10 MW Wind Turbine

    DEFF Research Database (Denmark)

    Zahle, Frederik; Tibaldi, Carlo; Verelst, David Robert

    2015-01-01

    This article describes a multi-disciplinary optimization and analysis tool for wind turbines that is based on the open-source framework OpenMDAO. Interfaces to several simulation codes have been implemented which allows for a wide variety of problem formulations and combinations of models. In thi...

  12. Calculation of wind turbine aeroelastic behaviour. The Garrad Hassan approach

    Energy Technology Data Exchange (ETDEWEB)

    Quarton, D.C. [Garrad Hassan and Partners Ltd., Bristol (United Kingdom)

    1996-09-01

    The Garrad Hassan approach to the prediction of wind turbine loading and response has been developed over the last decade. The goal of this development has been to produce calculation methods that contain realistic representation of the wind, include sensible aerodynamic and dynamic models of the turbine and can be used to predict fatigue and extreme loads for design purposes. The Garrad Hassan calculation method is based on a suite of four key computer programs: WIND3D for generation of the turbulent wind field; EIGEN for modal analysis of the rotor and support structure; BLADED for time domain calculation of the structural loads; and SIGNAL for post-processing of the BLADED predictions. The interaction of these computer programs is illustrated. A description of the main elements of the calculation method will be presented. (au)

  13. Aeroelastically coupled blades for vertical axis wind turbines

    Science.gov (United States)

    Paquette, Joshua; Barone, Matthew F.

    2016-02-23

    Various technologies described herein pertain to a vertical axis wind turbine blade configured to rotate about a rotation axis. The vertical axis wind turbine blade includes at least an attachment segment, a rear swept segment, and optionally, a forward swept segment. The attachment segment is contiguous with the forward swept segment, and the forward swept segment is contiguous with the rear swept segment. The attachment segment includes a first portion of a centroid axis, the forward swept segment includes a second portion of the centroid axis, and the rear swept segment includes a third portion of the centroid axis. The second portion of the centroid axis is angularly displaced ahead of the first portion of the centroid axis and the third portion of the centroid axis is angularly displaced behind the first portion of the centroid axis in the direction of rotation about the rotation axis.

  14. Reduced-order LPV model of flexible wind turbines from high fidelity aeroelastic codes

    DEFF Research Database (Denmark)

    Adegas, Fabiano Daher; Sønderby, Ivan Bergquist; Hansen, Morten Hartvig

    2013-01-01

    of high-order linear time invariant (LTI) models. Firstly, the high-order LTI models are locally approximated using modal and balanced truncation and residualization. Then, an appropriate coordinate transformation is applied to allow interpolation of the model matrices between points on the parameter...... space. The obtained LPV model is of suitable size for designing modern gain-scheduling controllers based on recently developed LPV control design techniques. Results are thoroughly assessed on a set of industrial wind turbine models generated by the recently developed aeroelastic code HAWCStab2....

  15. Trailed vorticity modeling for aeroelastic wind turbine simulations in stand still

    DEFF Research Database (Denmark)

    Pirrung, Georg; Aagaard Madsen, Helge; Schreck, Scott

    2016-01-01

    Current fast aeroelastic wind turbine codes suitable for certification lack an induction model for standstill conditions. A trailed vorticity model previously used as addition to a blade element momentum theory based aerodynamic model in normal operation has been extended to allow computing...... the steady loading for the Phase VI blade in attached flow. The prediction of the dynamic force coefficient loops from the Phase VI experiment is improved by the trailed vorticity modeling in both attached flow and stall in most cases. The exception is the tangential force coefficient in stall, where...

  16. Effect of steady deflections on the aeroelastic stability of a turbine blade

    DEFF Research Database (Denmark)

    Kallesøe, Bjarne Skovmose

    2011-01-01

    This paper deals with effects of geometric non-linearities on the aeroelastic stability of a steady-state defl ected blade. Today, wind turbine blades are long and slender structures that can have a considerable steady-state defl ection which affects the dynamic behaviour of the blade. The fl...... apwise blade defl ection causes the edgewise blade motion to couple to torsional blade motion and thereby to the aerodynamics through the angle of attack. The analysis shows that in the worst case for this particular blade, the edgewise damping can be decreased by half. Copyright © 2010 John Wiley & Sons......, Ltd....

  17. Methods and advances in the study of aeroelasticity with uncertainties

    Directory of Open Access Journals (Sweden)

    Dai Yuting

    2014-06-01

    Full Text Available Uncertainties denote the operators which describe data error, numerical error and model error in the mathematical methods. The study of aeroelasticity with uncertainty embedded in the subsystems, such as the uncertainty in the modeling of structures and aerodynamics, has been a hot topic in the last decades. In this paper, advances of the analysis and design in aeroelasticity with uncertainty are summarized in detail. According to the non-probabilistic or probabilistic uncertainty, the developments of theories, methods and experiments with application to both robust and probabilistic aeroelasticity analysis are presented, respectively. In addition, the advances in aeroelastic design considering either probabilistic or non-probabilistic uncertainties are introduced along with aeroelastic analysis. This review focuses on the robust aeroelasticity study based on the structured singular value method, namely the μ method. It covers the numerical calculation algorithm of the structured singular value, uncertainty model construction, robust aeroelastic stability analysis algorithms, uncertainty level verification, and robust flutter boundary prediction in the flight test, etc. The key results and conclusions are explored. Finally, several promising problems on aeroelasticity with uncertainty are proposed for future investigation.

  18. OC3—Benchmark Exercise of Aero-elastic Offshore Wind Turbine Codes

    Science.gov (United States)

    Passon, P.; Kühn, M.; Butterfield, S.; Jonkman, J.; Camp, T.; Larsen, T. J.

    2007-07-01

    This paper introduces the work content and status of the first international investigation and verification of aero-elastic codes for offshore wind turbines as performed by the "Offshore Code Comparison Collaboration"(OC3) within the "IEA Wind Annex XXIII - Subtask 2". An overview is given on the state-of-the-art of the concerned offshore wind turbine simulation codes. Exemplary results of benchmark simulations from the first phase of the project are presented and discussed while subsequent phases are introduced. Furthermore, the paper discusses areas where differences between the codes have been identified and the sources of those differences, such as the differing theories implemented into the individual codes. Finally, further research and code development needs are presented based on the latest findings from the current state of the project.

  19. Open-loop frequency response analysis of a wind turbine using a high-order linear aeroelastic model

    DEFF Research Database (Denmark)

    Sønderby, Ivan Bergquist; Hansen, Morten Hartvig

    2014-01-01

    generator torque and collective pitch control actions of a modern non-floating wind turbine based on a high-order linear model. The model is a linearization of a geometrically non-linear finite beam element model coupled with an unsteady blade element momentum model of aerodynamic forces including effects......Wind turbine controllers are commonly designed on the basis of low-order linear models to capture the aeroelastic wind turbine response due to control actions and disturbances. This paper characterizes the aeroelastic wind turbine dynamics that influence the open-loop frequency response from......-minimum phase zeros below the frequency of the first drivetrain mode. To correctly predict the non-minimum phase zeros, it is essential to include lateral tower and blade flap degrees of freedom. Copyright © 2013 John Wiley & Sons, Ltd....

  20. Aeroelastic modelling and comparison of advanced active flap control concepts for load reduction on the Upwind 5MW wind turbine

    NARCIS (Netherlands)

    Barlas, A.; van Kuik, G.A.M.

    2009-01-01

    A newly developed comprehensive aeroelastic model is used to investigate active flap concepts on the Upwind 5MW reference wind turbine. The model is specially designed to facilitate distributed control concepts and advanced controller design. Different concepts of centralized and distributed control

  1. Aeroelastic Modelling and Comparison of Advanced Active Flap Control Concepts for Load Reduction on the Upwind 5MW Wind Turbine

    NARCIS (Netherlands)

    Barlas, A.; Van Kuik, G.A.M.

    2009-01-01

    A newly developed comprehensive aeroelastic model is used to investigate active flap concepts on the Upwind 5MW reference wind turbine. The model is specially designed to facilitate distributed control concepts and advanced controller design. Different concepts of centralized and distributed control

  2. Numerical techniques for the improved performance of a finite element approach to wind turbine aeroelastics

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, M.B. [Renewable Energy Systems Ltd., Hemel Hempstead (United Kingdom)

    1996-09-01

    It is possible to compute the aeroelastic response of a horizontal axis wind turbine comprising; Structural: rotor substructure 144 dof, tower substructure 48 dof, induction, synchronous or variable speed, and gearbox. Aerodynamic: 3 blades (10 elements per blade), dynamic stall, and 6 different aerofoil types with combination of fixed or pitching elements. Control: stall or power regulation or speed control and shutdowns, wind shear, and tower shadow. Turbulence: 8 radial points, 32 circumferential, and 3 components. On a DEC Alpha Workstation the code will simulate the response inclose to real-time. As the code is presently formulated deflections from the initial starting point have to be small and therefore its ability to fully analyse very flexible structures is limited. (EG)

  3. Verification of aero-elastic offshore wind turbine design codes under IEA Wind Task XXIII

    DEFF Research Database (Denmark)

    Vorpahl, Fabian; Strobel, Michael; Jonkman, Jason M.

    2014-01-01

    This work presents the results of a benchmark study on aero-servo-hydro-elastic codes for offshore wind turbine dynamic simulation. The codes verified herein account for the coupled dynamic systems including the wind inflow, aerodynamics, elasticity and controls of the turbine, along with the inc...

  4. Aeroelastic and stability behaviour of the WTS 3 Maglarp wind turbine. Calculations and comparisons with tests

    Energy Technology Data Exchange (ETDEWEB)

    Soederberg, M.

    1990-01-01

    The GAROS system for general analysis of rotating aeroelastic structures is used to analyse the behaviour of the WTS 3 Maglarp wind turbine, situated in Maglarp, Sweden. The GAROS method is based on a branch mode technique and modal reduction. Stability analyses of the total tower-rotor system as well as numerical time integration analyses are performed within the GAROS system. The FE-model made by Anders Henoch, AIMS, for FFA is used as a base for this investigation. Some modifications concerning center of gravity of the rotor and teeter bearing/hinge have been made in the finite element model. In this report simulated values of loads in the blades are compaed to measured data. The unstable yaw behaviour of the WTS 3 was also found in the behaviour of the model. The amount of yaw-angle rotation in the model was also found to be according to measured values when induced velocities were accounted for in the aerodynamic force calculations. The analyses in general show good agreement between simulated and measured values. This paper was presented at the European Wind Energy Conference in Glasgow, 10-13 July, 1989.

  5. Assessment of dynamic substructuring of a wind turbine foundation applicable for aeroelastic simulations

    DEFF Research Database (Denmark)

    Damgaard, Mads; Andersen, Lars Vabbersgaard; Ibsen, Lars Bo

    2015-01-01

    -parameter model fitted to the frequency response of the ground, a surface foundation is implemented into the aeroelastic code FLEX5. In case of a horizontal stratum overlaying a homogeneous half-space and within the low frequency range, analyses show that a standard lumped-parametermodel provides an accurate...

  6. Combined Structural Optimization and Aeroelastic Analysis of a Vertical Axis Wind Turbine

    DEFF Research Database (Denmark)

    Roscher, Björn; Ferreira, Carlos Simao; Bernhammer, Lars O.

    2015-01-01

    Floating offshore wind energy poses challenges on the turbine design. A possible solution is vertical axis wind turbines, which are possibly easier to scale-up and require less components (lower maintenance) and a smaller floating structure than horizontal axis wind turbines. This paper presents ...

  7. FAST v8 Verification and Validation for a Megawatt-Scale Wind Turbine with Aeroelastically Tailored Blades: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Guntur, Sirnivas; Jonkman, Jason; Schreck, Scott; Jonkman, Bonnie; Wang, Qi; Sprague, Michael; Hind, Michael; Sievers, Ryan

    2016-01-27

    This paper presents findings from a verification and validation exercise on the latest version of the U.S. Department of Energy/National Renewable Energy Laboratory's in-house wind turbine aeroelastic design code FAST v8. Results from a set of 1141 FAST simulations were compared to those from Siemens' BHawC design code results, as well as experimental data from a heavily instrumented 2.3-MW Siemens wind turbine located at the National Wind Technology Center. The code validation was performed following the IEC-61400-13 standard, where a set of select quantities of interest from simulations at various wind speed and atmospheric turbulence conditions were used for a three-way comparison between FAST, BHawC, and the measurements. Results highlight many improvements of the latest version of FAST over its previous versions. This paper also provides comments from the authors on the data quality, and avenues for potential future work using these results.

  8. Analysis of the Drivetrain Performance of a Large Horizontal-Axis Wind Turbine: An Aeroelastic Approach

    DEFF Research Database (Denmark)

    Gebhardt, Cristian; Preidikman, Sergio; Massa, Julio C

    2010-01-01

    blades’, the drivetrain and the generator. The blades are the part of the turbine that touches energy in the wind and rotates about an axis. Extracting energy from the wind is typically accomplished by first mechanically converting the velocity of the wind into a rotational motion of the wind turbine...... scheme are implemented in a computational tool; and by using it, the behavior of the turbine in the starting initial regime is investigated, considering different laws of brake releasing. The capability to simulate these phenomena is one of the novel aspects in the present effort....

  9. On the aero-elastic design of the DTU 10MW wind turbine blade for the LIFES50+ wind tunnel scale model

    DEFF Research Database (Denmark)

    Bayati, I.; Belloli, M.; Bernini, L.

    2016-01-01

    This paper illustrates the aero-elastic optimal design, the realization and the verification of the wind tunnel scale model blades for the DTU 10 MW wind turbine model, within LIFES50+ project. The aerodynamic design was focused on the minimization of the difference, in terms of thrust coefficient...... and for different angles of attack. The aero-elastic design algorithm was set to define the optimal spanwise thickness over chord ratio (t/c), the chord length and the twist to match the first flapwise scaled natural frequency. An aluminium mould for the carbon fibre was CNC manufactured based on B-Splines CAD...... definition of the external geometry. Then the wind tunnel tests at Politecnico di Milano confirmed successful design and manufacturing approaches....

  10. Exploratory Studies in Generalized Predictive Control for Active Aeroelastic Control of Tiltrotor Aircraft

    Science.gov (United States)

    Kvaternik, Raymond G.; Juang, Jer-Nan; Bennett, Richard L.

    2000-01-01

    The Aeroelasticity Branch at NASA Langley Research Center has a long and substantive history of tiltrotor aeroelastic research. That research has included a broad range of experimental investigations in the Langley Transonic Dynamics Tunnel (TDT) using a variety of scale models and the development of essential analyses. Since 1994, the tiltrotor research program has been using a 1/5-scale, semispan aeroelastic model of the V-22 designed and built by Bell Helicopter Textron Inc. (BHTI) in 1981. That model has been refurbished to form a tiltrotor research testbed called the Wing and Rotor Aeroelastic Test System (WRATS) for use in the TDT. In collaboration with BHTI, studies under the current tiltrotor research program are focused on aeroelastic technology areas having the potential for enhancing the commercial and military viability of tiltrotor aircraft. Among the areas being addressed, considerable emphasis is being directed to the evaluation of modern adaptive multi-input multi- output (MIMO) control techniques for active stability augmentation and vibration control of tiltrotor aircraft. As part of this investigation, a predictive control technique known as Generalized Predictive Control (GPC) is being studied to assess its potential for actively controlling the swashplate of tiltrotor aircraft to enhance aeroelastic stability in both helicopter and airplane modes of flight. This paper summarizes the exploratory numerical and experimental studies that were conducted as part of that investigation.

  11. Uncertainty propagation through an aeroelastic wind turbine model using polynomial surrogates

    DEFF Research Database (Denmark)

    Murcia Leon, Juan Pablo; Réthoré, Pierre-Elouan; Dimitrov, Nikolay Krasimirov

    2018-01-01

    -alignment. The methodology presented extends the deterministic power and thrust coefficient curves to uncertainty models and adds new variables like damage equivalent fatigue loads in different components of the turbine. These surrogate models can then be implemented inside other work-flows such as: estimation......Polynomial surrogates are used to characterize the energy production and lifetime equivalent fatigue loads for different components of the DTU 10 MW reference wind turbine under realistic atmospheric conditions. The variability caused by different turbulent inflow fields are captured by creating...... of the uncertainty in annual energy production due to wind resource variability and/or robust wind power plant layout optimization. It can be concluded that it is possible to capture the global behavior of a modern wind turbine and its uncertainty under realistic inflow conditions using polynomial response surfaces...

  12. Structural Optimization Design of Large Wind Turbine Blade considering Aeroelastic Effect

    Directory of Open Access Journals (Sweden)

    Yuqiao Zheng

    2017-01-01

    Full Text Available This paper presents a structural optimization design of the realistic large scale wind turbine blade. The mathematical simulations have been compared with experimental data found in the literature. All complicated loads were applied on the blade when it was working, which impacts directly on mixed vibration of the wind rotor, tower, and other components, and this vibration can dramatically affect the service life and performance of wind turbine. The optimized mathematical model of the blade was established in the interaction between aerodynamic and structural conditions. The modal results show that the first six modes are flapwise dominant. Meanwhile, the mechanism relationship was investigated between the blade tip deformation and the load distribution. Finally, resonance cannot occur in the optimized blade, as compared to the natural frequency of the blade. It verified that the optimized model is more appropriate to describe the structure. Additionally, it provided a reference for the structural design of a large wind turbine blade.

  13. Design and Aero-elastic Simulation of a 5MW Floating Vertical Axis Wind Turbine

    DEFF Research Database (Denmark)

    Vita, Luca; Schmidt Paulsen, Uwe; Aagaard Madsen, Helge

    2013-01-01

    This paper deals with the design of a 5MW floating offshore Vertical Axis Wind Turbine (VAWT). The design is based on a new offshore wind turbine concept (DeepWind concept), consisting of a Darrieus rotor mounted on a spar buoy support structure, which is anchored to the sea bed with mooring lines...... technology, which can be improved in the future with new dedicated technological solutions. The rotor uses curved blades, which are designed in order to minimize the gravitational loads and to be produced by the pultrusion process. The floating platform is a slender cylindrical structure rotating along...

  14. Coupling analysis of wind turbine blades based on aeroelastics and aerodynsmics

    DEFF Research Database (Denmark)

    Wang, Xudong; Chen, Jin; Zhang, Shigiang

    2010-01-01

    The structural dynamic equations of blades were constructed for blades of wind turbines. The vibration velocity of blades and the relative flow velocity were calculated using the structural dynamics model. Based on the BEM (Blade Element Momentum) theory and traditional areodynamics, the coupling...

  15. Validation of a vortex ring wake model suited for aeroelastic simulations of floating wind turbines

    DEFF Research Database (Denmark)

    Vaal, J.B., de; Hansen, Martin Otto Laver; Moan, T.

    2014-01-01

    In order to evaluate aerodynamic loads on floating oshore wind turbines, advanced dynamic analysis tools are required. As a unied model that can represent both dynamic in ow and skewed in ow effects in it basic formulation, a wake model based on a vortex ring formulation is discussed. Such a model...... presents a good intermediate solution between computationally efficient but simple momentum balance methods and computationally expensive but complete computational fluid dynamics models. The model introduced is shown to be capable of modelling typical steady and unsteady test cases with reasonable...

  16. The aeroelastic code FLEXLAST

    Energy Technology Data Exchange (ETDEWEB)

    Visser, B. [Stork Product Eng., Amsterdam (Netherlands)

    1996-09-01

    To support the discussion on aeroelastic codes, a description of the code FLEXLAST was given and experiences within benchmarks and measurement programmes were summarized. The code FLEXLAST has been developed since 1982 at Stork Product Engineering (SPE). Since 1992 FLEXLAST has been used by Dutch industries for wind turbine and rotor design. Based on the comparison with measurements, it can be concluded that the main shortcomings of wind turbine modelling lie in the field of aerodynamics, wind field and wake modelling. (au)

  17. Aeroelastic Uncertainty Quantification Studies Using the S4T Wind Tunnel Model

    Science.gov (United States)

    Nikbay, Melike; Heeg, Jennifer

    2017-01-01

    This paper originates from the joint efforts of an aeroelastic study team in the Applied Vehicle Technology Panel from NATO Science and Technology Organization, with the Task Group number AVT-191, titled "Application of Sensitivity Analysis and Uncertainty Quantification to Military Vehicle Design." We present aeroelastic uncertainty quantification studies using the SemiSpan Supersonic Transport wind tunnel model at the NASA Langley Research Center. The aeroelastic study team decided treat both structural and aerodynamic input parameters as uncertain and represent them as samples drawn from statistical distributions, propagating them through aeroelastic analysis frameworks. Uncertainty quantification processes require many function evaluations to asses the impact of variations in numerous parameters on the vehicle characteristics, rapidly increasing the computational time requirement relative to that required to assess a system deterministically. The increased computational time is particularly prohibitive if high-fidelity analyses are employed. As a remedy, the Istanbul Technical University team employed an Euler solver in an aeroelastic analysis framework, and implemented reduced order modeling with Polynomial Chaos Expansion and Proper Orthogonal Decomposition to perform the uncertainty propagation. The NASA team chose to reduce the prohibitive computational time by employing linear solution processes. The NASA team also focused on determining input sample distributions.

  18. Modeling Complex Dynamic Interactions of Nonlinear, Aeroelastic, Multistage, and Localization Phenomena in Turbine Engines

    Science.gov (United States)

    2011-02-25

    wavelet analyses, evolutionary algorithms, Ritz or stochastic methods, and others. These techniques are designed for linear vibrations while far...and selecting DOF of FE models have been extensively studied by var - ious methods and distinct perspectives, such as the reduction of the interface DOF

  19. Advanced turbine study

    Science.gov (United States)

    Castro, J. H.

    1985-01-01

    The feasibility of an advanced convective cooling concept applied to rocket turbine airfoils which operate in a high pressure hydrogen and methane environment was investigated. The concept consists of a central structural member in which grooves are machined. The grooves are temporarily filled with a removable filler and the entire airfoil is covered with a layer of electroformed nickel, or nickel base alloy. After removal of the filler, the low thermal resistance of the nickel closure causes the wall temperature to be reduced by heat transfer to the coolant. The program is divided in the following tasks: (1) turbine performance appraisal; (2) coolant geometry evaluation; (3) test hardware design and analysis; and (4) test airfoil fabrication.

  20. Aeroservoelasticity of wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    Skovmose Kallesoee, B.

    2007-12-14

    This thesis deals with the fundamental aeroelastic interaction between structural motion, Pitch action and control for a wind turbine blade. As wind turbines become larger, the interaction between pitch action, blade motion, aerodynamic forces, and control become even more important to understand and address. The main contribution of this thesis is the development of an aeroelastic blade model which on the one hand includes the important effects of steady state blade deformation, gravity and pitch action, and on the other it is transparent, suitable for analytical analysis and parameter studies, and furthermore linear and therefore suitable for control design. The development of the primary aeroelastic blade model is divided into four steps: 1) Nonlinear partial differential equations (PDEs) of structural blade motion are derived together with equations of pitch action and rotor speed; the individual terms in these equations are discussed and given physical interpretations; 2) Steady state blade deformation and induced velocities are computed by combining the PDEs with a steady state aerodynamic model; 3) Aeroelastic modes of motion are computed by combining the linearized PDEs with a linear unsteady aerodynamic model; this model is used to analyze how blade deformation effects the modes of motion; and 4) the linear aeroelastic blade model is derived by a modal expansion of the linearized PDEs combined with a linear unsteady aerodynamic model. The aeroelastic blade model has many similarities to a 2D blade section model, and it can be used instead of this in many applications, giving a transparent connection to a real wind turbine blade. In this work the aeroelastic blade model is used to analyze interaction between pitch action, blade motion and wind speed variations. Furthermore the model is used to develop a state estimator for estimating the wind speed and wind shear, and to suggest a load reducing controller. The state estimator estimates the wind shear very

  1. Numerical studies of static aeroelastic effects on grid fin aerodynamic performances

    Directory of Open Access Journals (Sweden)

    Chengde HUANG

    2017-08-01

    Full Text Available The grid fin is an unconventional control surface used on missiles and rockets. Although aerodynamics of grid fin has been studied by many researchers, few considers the aeroelastic effects. In this paper, the static aeroelastic simulations are performed by the coupled viscous computational fluid dynamics with structural flexibility method in transonic and supersonic regimes. The developed coupling strategy including fluid–structure interpolation and volume mesh motion schemes is based on radial basis functions. Results are presented for a vertical and a horizontal grid fin mounted on a body. Horizontal fin results show that the deformed fin is swept backward and the axial force is increased. The deformations also induce the movement of center of pressure, causing the reduction and reversal in hinge moment for the transonic flow and the supersonic flow, respectively. For the vertical fin, the local effective incidences are increased due to the deformations so that the deformed normal force is greater than the original one. At high angles of attack, both the deformed and original normal forces experience a sudden reduction due to the interference of leeward separated vortices on the fin. Additionally, the increment in axial force is shown to correlate strongly with the increment in the square of normal force.

  2. Aeroelastic impact of above-rated wave-induced structural motions on the near-wake stability of a floating offshore wind turbine rotor

    Science.gov (United States)

    Rodriguez, Steven; Jaworski, Justin

    2017-11-01

    The impact of above-rated wave-induced motions on the stability of floating offshore wind turbine near-wakes is studied numerically. The rotor near-wake is generated using a lifting-line free vortex wake method, which is strongly coupled to a finite element solver for kinematically nonlinear blade deformations. A synthetic time series of relatively high-amplitude/high-frequency representative of above-rated conditions of the NREL 5MW referece wind turbine is imposed on the rotor structure. To evaluate the impact of these above-rated conditions, a linear stability analysis is first performed on the near wake generated by a fixed-tower wind turbine configuration at above-rated inflow conditions. The platform motion is then introduced via synthetic time series, and a stability analysis is performed on the wake generated by the floating offshore wind turbine at the same above-rated inflow conditions. The stability trends (disturbance modes versus the divergence rate of vortex structures) of the two analyses are compared to identify the impact that above-rated wave-induced structural motions have on the stability of the floating offshore wind turbine wake.

  3. Vertical Axis Wind Turbine Design Load Cases Investigation and Comparison with Horizontal Axis Wind Turbine

    DEFF Research Database (Denmark)

    Galinos, Christos; Larsen, Torben J.; Aagaard Madsen, Helge

    2016-01-01

    The paper studies the applicability of the IEC 61400-1 ed.3, 2005 International Standard of wind turbine minimum design requirements in the case of an onshore Darrieus VAWT and compares the results of basic Design Load Cases (DLCs) with those of a 3-bladed HAWT. The study is based on aeroelastic ...

  4. Integrated analysis of wind turbines - The impact of power systems on wind turbine design

    DEFF Research Database (Denmark)

    Barahona Garzón, Braulio

    of the integrated simulation environment are presented. The analysis of an asynchronous machine, and numerical simulations of a fixedspeed wind turbine in the integrated simulation environment, demonstrate the effects on structural loads of including the generator rotor fluxes dynamics in aeroelastic studies. Power...

  5. NEXT GENERATION TURBINE SYSTEM STUDY

    Energy Technology Data Exchange (ETDEWEB)

    Frank Macri

    2002-02-28

    Rolls-Royce has completed a preliminary design and marketing study under a Department of Energy (DOE) cost shared contract (DE-AC26-00NT40852) to analyze the feasibility of developing a clean, high efficiency, and flexible Next Generation Turbine (NGT) system to meet the power generation market needs of the year 2007 and beyond. Rolls-Royce evaluated the full range of its most advanced commercial aerospace and aeroderivative engines alongside the special technologies necessary to achieve the aggressive efficiency, performance, emissions, economic, and flexibility targets desired by the DOE. Heavy emphasis was placed on evaluating the technical risks and the economic viability of various concept and technology options available. This was necessary to ensure the resulting advanced NGT system would provide extensive public benefits and significant customer benefits without introducing unacceptable levels of technical and operational risk that would impair the market acceptance of the resulting product. Two advanced cycle configurations were identified as offering significant advantages over current combined cycle products available in the market. In addition, balance of plant (BOP) technologies, as well as capabilities to improve the reliability, availability, and maintainability (RAM) of industrial gas turbine engines, have been identified. A customer focused survey and economic analysis of a proposed Rolls-Royce NGT product configuration was also accomplished as a part of this research study. The proposed Rolls-Royce NGT solution could offer customers clean, flexible power generation systems with very high efficiencies, similar to combined cycle plants, but at a much lower specific cost, similar to those of simple cycle plants.

  6. Smart dynamic rotor control using active flaps on a small-scale wind turbine: aeroelastic modeling and comparison with wind tunnel measurements

    DEFF Research Database (Denmark)

    Barlas, Thanasis K.; van Wingerden, W.; Hulskamp, A.W.

    2013-01-01

    In this paper, the proof of concept of a smart rotor is illustrated by aeroelastic simulations on a small-scale rotor and comparison with wind tunnel experiments. The application of advanced feedback controllers using actively deformed flaps in the wind tunnel measurements is shown to alleviate d...

  7. Shape Optimization of Wind Turbine Blades

    DEFF Research Database (Denmark)

    Wang, Xudong; Shen, Wen Zhong; Zhu, Wei Jun

    2009-01-01

    of the rotor. The design variables used in the current study are the blade shape parameters, including chord, twist and relative thickness. To validate the implementation of the aerodynamic/aero-elastic model, the computed aerodynamic results are compared to experimental data for the experimental rotor used......This paper presents a design tool for optimizing wind turbine blades. The design model is based on an aerodynamic/aero-elastic code that includes the structural dynamics of the blades and the Blade Element Momentum (BEM) theory. To model the main aero-elastic behaviour of a real wind turbine...... in the European Commision-sponsored project Model Experiments in Controlled Conditions, (MEXICO) and the computed aero-elastic results are examined against the FLEX code for flow post the Tjereborg 2 MW rotor. To illustrate the optimization technique, three wind turbine rotors of different sizes (the MEXICO 25 k...

  8. A Novel Wind Turbine Concept Based on an Electromagnetic Coupler and the Study of Its Fault Ride-through Capability

    Directory of Open Access Journals (Sweden)

    Rui You

    2013-11-01

    Full Text Available This paper presents a novel type of variable speed wind turbine with a new drive train different from the variable speed wind turbine commonly used nowadays. In this concept, a synchronous generator is directly coupled with the grid, therefore, the wind turbine transient overload capability and grid voltage support capability can be significantly improved. An electromagnetic coupling speed regulating device (EMCD is used to connect the gearbox high speed shaft and synchronous generator rotor shaft, transmitting torque to the synchronous generator, while decoupling the gearbox side and the synchronous generator, so the synchronous generator torque oscillations during a grid fault are not transmitted to the gearbox. The EMCD is composed of an electromagnetic coupler and a one quadrant operation converter with reduced capability and low cost. A control strategy for the new wind turbine is proposed and a 2 MW wind turbine model is built to study the wind turbine fault ride-through capability. An integrated simulation environment based on the aeroelastic code HAWC2 and software Matlab/Simulink is used to study its fault ride-through capability and the impact on the structural loads during grid three phase and two phase short circuit faults.

  9. Advanced turbine study. [airfoil coling in rocket turbines

    Science.gov (United States)

    1982-01-01

    Experiments to determine the available increase in turbine horsepower achieved by increasing turbine inlet temperature over a range of 1800 to 2600 R, while applying current gas turbine airfoil cling technology are discussed. Four cases of rocket turbine operating conditions were investigated. Two of the cases used O2/H2 propellant, one with a fuel flowrate of 160 pps, the other 80 pps. Two cases used O2/CH4 propellant, each having different fuel flowrates, pressure ratios, and inlet pressures. Film cooling was found to be the required scheme for these rocket turbine applications because of the high heat flux environments. Conventional convective or impingement cooling, used in jet engines, is inadequate in a rocket turbine environment because of the resulting high temperature gradients in the airfoil wall, causing high strains and low cyclic life. The hydrogen-rich turbine environment experienced a loss, or no gain, in delivered horsepower as turbine inlet temperature was increased at constant airfoil life. The effects of film cooling with regard to reduced flow available for turbine work, dilution of mainstream gas temperature and cooling reentry losses, offset the relatively low specific work capability of hydrogen when increasing turbine inlet temperature over the 1800 to 2600 R range. However, the methane-rich environment experienced an increase in delivered horsepower as turbine inlet temperature was increased at constant airfoil life. The results of a materials survey and heat transfer and durability analysis are discussed.

  10. Load prediction of stall regulated wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    Bjoerck, A.; Dahlberg, J.Aa. [Aeronautical Research Inst. of Sweden, Bromma (Sweden); Carlen, I. [Chalmers Univ. of Technology, Goeteborg (Sweden). Div. of Marine Structural Engineering; Ganander, H. [Teknikgruppen AB, Sollentua (Sweden)

    1996-12-01

    Measurements of blade loads on a turbine situated in a small wind farm shows that the highest blade loads occur during operation close to the peak power i.e. when the turbine operates in the stall region. In this study the extensive experimental data base has been utilised to compare loads in selected campaigns with corresponding load predictions. The predictions are based on time domain simulations of the wind turbine structure, performed by the aeroelastic code VIDYN. In the calculations a model were adopted in order to include the effects of dynamic stall. This paper describes the work carried out so far within the project and key results. 5 refs, 10 figs

  11. Effects of torsional degree of freedom, geometric nonlinearity, and gravity on aeroelastic behavior of large-scale horizontal axis wind turbine blades under varying wind speed conditions

    DEFF Research Database (Denmark)

    Jeong, Min-Soo; Cha, Myung-Chan; Kim, Sang-Woo

    2014-01-01

    Modern horizontal axis wind turbine blades are long, slender, and flexible structures that can undergo considerable deformation, leading to blade failures (e.g., blade-tower collision). For this reason, it is important to estimate blade behaviors accurately when designing large-scale wind turbine...

  12. Harmonic Balance Computations of Fan Aeroelastic Stability

    Science.gov (United States)

    Bakhle, Milind A.; Reddy, T. S. R.

    2010-01-01

    A harmonic balance (HB) aeroelastic analysis, which has been recently developed, was used to determine the aeroelastic stability (flutter) characteristics of an experimental fan. To assess the numerical accuracy of this HB aeroelastic analysis, a time-domain aeroelastic analysis was also used to determine the aeroelastic stability characteristics of the same fan. Both of these three-dimensional analysis codes model the unsteady flowfield due to blade vibrations using the Reynolds-averaged Navier-Stokes (RANS) equations. In the HB analysis, the unsteady flow equations are converted to a HB form and solved using a pseudo-time marching method. In the time-domain analysis, the unsteady flow equations are solved using an implicit time-marching approach. Steady and unsteady computations for two vibration modes were carried out at two rotational speeds: 100 percent (design) and 70 percent (part-speed). The steady and unsteady results obtained from the two analysis methods compare well, thus verifying the recently developed HB aeroelastic analysis. Based on the results, the experimental fan was found to have no aeroelastic instability (flutter) at the conditions examined in this study.

  13. Aeroelastic oscillations of a cantilever with structural nonlinearities: theory and numerical simulation.

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, Brandon [Carleton Univ., Ottawa, ON (Canada). Dept. of Civil and Environmental Engineering; Rocha da Costa, Leandro Jose [Carleton Univ., Ottawa, ON (Canada). Dept. of Civil and Environmental Engineering; Poirel, Dominique [Royal Military College of Canada, Kingston (Canada). Dept. of Mechanical and Aerospace Engineering; Pettit, Chris [US Naval Academy, Annapolis, MD (United States). Dept. of Mechanical and Aerospace Engineering; Khalil, Mohammad [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Sarkar, Abhijit [Carleton Univ., Ottawa, ON (Canada). Dept. of Civil and Environmental Engineering

    2017-09-01

    Our study details the derivation of the nonlinear equations of motion for the axial, biaxial bending and torsional vibrations of an aeroelastic cantilever undergoing rigid body (pitch) rotation at the base. The primary attenstion is focussed on the geometric nonlinearities of the system, whereby the aeroelastic load is modeled by the theory of linear quasisteady aerodynamics. This modelling effort is intended to mimic the wind-tunnel experimental setup at the Royal Military College of Canada. While the derivation closely follows the work of Hodges and Dowell [1] for rotor blades, this aeroelastic system contains new inertial terms which stem from the fundamentally different kinematics than those exhibited by helicopter or wind turbine blades. Using the Hamilton’s principle, a set of coupled nonlinear partial differential equations (PDEs) and an ordinary differential equation (ODE) are derived which describes the coupled axial-bending-bending-torsion-pitch motion of the aeroelastic cantilever with the pitch rotation. The finite dimensional approximation of the coupled system of PDEs are obtained using the Galerkin projection, leading to a coupled system of ODEs. Subsequently, these nonlinear ODEs are solved numerically using the built-in MATLAB implicit ODE solver and the associated numerical results are compared with those obtained using Houbolt’s method. It is demonstrated that the system undergoes coalescence flutter, leading to a limit cycle oscillation (LCO) due to coupling between the rigid body pitching mode and teh flexible mode arising from the flapwise bending motion.

  14. Generator dynamics in aeroelastic analysis and simulations

    Energy Technology Data Exchange (ETDEWEB)

    Larsen, T.J.; Hansen, M.H.; Iov, F.

    2003-05-01

    This report contains a description of a dynamic model for a doubly-fed induction generator implemented in the aeroelastic code HAWC. The model has physical input parameters (resistance, reactance etc.) and input variables (stator and rotor voltage and rotor speed). The model can be used to simulate the generator torque as well as the rotor and stator currents, active and reactive power. A perturbation method has been used to reduce the original generator model equations to a set of equations which can be solved with the same time steps as a typical aeroelastic code. The method is used to separate the fast transients of the model from the slow variations and deduce a reduced order expression for the slow part. Dynamic effects of the first order terms in the model as well as the influence on drive train eigenfrequencies and damping has been investigated. Load response during time simulation of wind turbine response have been compared to simulations with a linear static generator model originally implemented i HAWC. A 2 MW turbine has been modelled in the aeroelastic code HAWC. When using the new dynamic generator model there is an interesting coupling between the generator dynamics and a global turbine vibration mode at 4.5 Hz, which only occurs when a dynamic formulation of the generator equations is applied. This frequency can especially be seen in the electrical power of the generator and the rotational speed of the generator, but also as torque variations in the drive train. (au)

  15. Aeroservoelasticity of Wind Turbines

    DEFF Research Database (Denmark)

    Kallesøe, Bjarne Skovmose

    2007-01-01

    This thesis deals with the fundamental aeroelastic interaction between structural motion, Pitch action and control for a wind turbine blade. As wind turbines become larger, the interaction between pitch action, blade motion, aerodynamic forces, and control become even more important to understand...... to a 2D blade section model, and it can be used instead of this in many applications, giving a transparent connection to a real wind turbine blade. In this work the aeroelastic blade model is used to analyze interaction between pitch action, blade motion and wind speed variations. Furthermore the model...... conditions. So, a new aeroelastic blade model has been derived, which includes important features of large wind turbines, yet simple enough to be suitable for analytical analysis and control design....

  16. NUMERICAL APPROACH IN AEROELASTICITY

    Directory of Open Access Journals (Sweden)

    Oskar SLOBODA

    2016-12-01

    Full Text Available Aircraft wing design processes should comprise specific analyses oriented towards aeroelasticity, which is one of the essential factors determining flight envelope boundaries. For such cases, static or dynamic aeroelastic phenomena can be simulated using CFD simulation software. ANSYS software offers the fluid structure interaction (FSI method for solving this multiphysics problem

  17. Hybrid Electro-Mechanical Simulation Tool for Wind Turbine Generators: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Singh, M.; Muljadi, E.; Jonkman, J.

    2013-05-01

    This paper describes the use of MATLAB/Simulink to simulate the electrical and grid-related aspects of a WTG and the FAST aero-elastic wind turbine code to simulate the aerodynamic and mechanical aspects of the WTG. The combination of the two enables studies involving both electrical and mechanical aspects of the WTG.

  18. Estimation of the wind turbine yaw error by support vector machines

    DEFF Research Database (Denmark)

    Sheibat-Othman, Nida; Othman, Sami; Tayari, Raoaa

    2015-01-01

    Wind turbine yaw error information is of high importance in controlling wind turbine power and structural load. Normally used wind vanes are imprecise. In this work, the estimation of yaw error in wind turbines is studied using support vector machines for regression (SVR). As the methodology...... is data-based, simulated data from a high fidelity aero-elastic model is used for learning. The model simulates a variable speed horizontal-axis wind turbine composed of three blades and a full converter. Both partial load (blade angles fixed at 0 deg) and full load zones (active pitch actuators...

  19. Study on the Interaction between Two Hydrokinetic Savonius Turbines

    Directory of Open Access Journals (Sweden)

    Kailash Golecha

    2012-01-01

    Full Text Available Savonius turbine is simple in design and easy to fabricate at a lower cost. The drag is the basic driving force for Savonius turbine. Savonius turbines are mainly used for the small-scale electricity generation in remote areas. In real life, multiple Savonius turbines are to be arranged to form a farm to scale up the electricity generation. So, it is important to study the interaction among them to avoid the power loss due to negative interaction between turbines. The purpose of this investigation is to examine closely the effect of interaction between two Savonius turbines arranged in line. Experimental investigations are carried out to study the mutual interaction between turbines with water as the working medium at a Reynolds number of 1.2×105 based on the diameter of the turbine. Influence of separation gap between the two Savonius turbines is studied by varying the separation gap ratio (/ from 3 to 8. As the separation gap ratio increases from 3 to 8, becomes lesser the mutual interaction between the turbines. Results conclude that two turbines placed at a separation gap ratio of 8 performed independently without affecting the performance of each other.

  20. Aeroelastic effects on stability and control of hingeless rotor helicopters

    Science.gov (United States)

    Celi, Roberto

    1988-01-01

    The combined effect of torsional flexibility and offset of the aerodynamic center relative to the elastic axis on the stability and control of a hingeless rotor helicopter in forward flight is studied in this paper. The aeroelastic model of the blade is based on fully coupled flap-lag-torsion equations of motion, which include kinematic nonlinearities due to moderate deflections. The equations are discretized using a finite element Galerkin method in space, and a classical Galerkin method in time. The vehicle trim calculations are coupled to the blade aeroelastic response calculations. Quasilinearization is used to compute aeroelastic stability. Reducing torsional stiffness and moving the elastic axis ahead of the aerodynamic center strongly stabilizes the phugoid mode without reducing control sensitivity. Aeroelastic stability calculations must accompany flight dynamics calculations to prevent aeroelastic instabilities that might easily go undetected.

  1. WindPACT Turbine Design Scaling Studies Technical Area 2: Turbine, Rotor and Blade Logistics; TOPICAL

    International Nuclear Information System (INIS)

    Smith, K.

    2001-01-01

    Through the National Renewable Energy Laboratory (NREL), the United States Department of Energy (DOE) implemented the Wind Partnership for Advanced Component Technologies (WindPACT) program. This program will explore advanced technologies that may reduce the cost of energy (COE) from wind turbines. The initial step in the WindPACT program is a series of preliminary scaling studies intended to determine the optimum sizes for future turbines, help define sizing limits for certain critical technologies, and explore the potential for advanced technologies to contribute to reduced COE as turbine scales increase. This report documents the results of Technical Area 2-Turbine Rotor and Blade Logistics. For this report, we investigated the transportation, assembly, and crane logistics and costs associated with installation of a range of multi-megawatt-scale wind turbines. We focused on using currently available equipment, assembly techniques, and transportation system capabilities and limitations to hypothetically transport and install 50 wind turbines at a facility in south-central South Dakota

  2. WindPACT Turbine Design Scaling Studies Technical Area 2: Turbine, Rotor and Blade Logistics

    Energy Technology Data Exchange (ETDEWEB)

    Smith, K.

    2001-07-16

    Through the National Renewable Energy Laboratory (NREL), the United States Department of Energy (DOE) implemented the Wind Partnership for Advanced Component Technologies (WindPACT) program. This program will explore advanced technologies that may reduce the cost of energy (COE) from wind turbines. The initial step in the WindPACT program is a series of preliminary scaling studies intended to determine the optimum sizes for future turbines, help define sizing limits for certain critical technologies, and explore the potential for advanced technologies to contribute to reduced COE as turbine scales increase. This report documents the results of Technical Area 2-Turbine Rotor and Blade Logistics. For this report, we investigated the transportation, assembly, and crane logistics and costs associated with installation of a range of multi-megawatt-scale wind turbines. We focused on using currently available equipment, assembly techniques, and transportation system capabilities and limitations to hypothetically transport and install 50 wind turbines at a facility in south-central South Dakota.

  3. Aerodynamics of wind turbines

    DEFF Research Database (Denmark)

    Hansen, Martin Otto Laver

    Aerodynamics of Wind Turbines is the established essential text for the fundamental solutions to efficient wind turbine design. Now in its third edition, it has been substantially updated with respect to structural dynamics and control. The new control chapter now includes details on how to design...... Turbines (VAWT). Topics covered include increasing mass flow through the turbine, performance at low and high wind speeds, assessment of the extreme conditions under which the turbine will perform and the theory for calculating the lifetime of the turbine. The classical Blade Element Momentum method...... is also covered, as are eigenmodes and the dynamic behaviour of a turbine. The book describes the effects of the dynamics and how this can be modelled in an aeroelastic code, which is widely used in the design and verification of modern wind turbines. Furthermore, it examines how to calculate...

  4. Aerodynamics of Wind Turbines

    DEFF Research Database (Denmark)

    Hansen, Martin Otto Laver

    Aerodynamics of Wind Turbines is the established essential text for the fundamental solutions to efficient wind turbine design. Now in its second edition, it has been entirely updated and substantially extended to reflect advances in technology, research into rotor aerodynamics and the structural...... response of the wind turbine structure. Topics covered include increasing mass flow through the turbine, performance at low and high wind speeds, assessment of the extreme conditions under which the turbine will perform and the theory for calculating the lifetime of the turbine. The classical Blade Element...... Momentum method is also covered, as are eigenmodes and the dynamic behavior of a turbine. The new material includes a description of the effects of the dynamics and how this can be modeled in an aeroelastic code, which is widely used in the design and verification of modern wind turbines. Further...

  5. Parametric study of composite wind turbine blades

    DEFF Research Database (Denmark)

    Kim, Taeseong; Branner, Kim; Hansen, Anders Melchior

    2011-01-01

    In this paper an anisotropic beam element for a composite wind turbine blades is developed. Eigenvalue analysis with the new beam element is conducted in order to understand its responses associated with the wind turbine performances. From the results of natural frequencies and mode shapes it is ...

  6. The aeroelastic code HawC - model and comparisons

    Energy Technology Data Exchange (ETDEWEB)

    Thirstrup Petersen, J. [Risoe National Lab., The Test Station for Wind Turbines, Roskilde (Denmark)

    1996-09-01

    A general aeroelastic finite element model for simulation of the dynamic response of horizontal axis wind turbines is presented. The model has been developed with the aim to establish an effective research tool, which can support the general investigation of wind turbine dynamics and research in specific areas of wind turbine modelling. The model concentrates on the correct representation of the inertia forces in a form, which makes it possible to recognize and isolate effects originating from specific degrees of freedom. The turbine structure is divided into substructures, and nonlinear kinematic terms are retained in the equations of motion. Moderate geometric nonlinearities are allowed for. Gravity and a full wind field including 3-dimensional 3-component turbulence are included in the loading. Simulation results for a typical three bladed, stall regulated wind turbine are presented and compared with measurements. (au)

  7. Chaotic Patterns in Aeroelastic Signals

    Directory of Open Access Journals (Sweden)

    F. D. Marques

    2009-01-01

    patterns. With the reconstructed state spaces, qualitative analyses may be done, and the attractors evolutions with parametric variation are presented. Overall results reveal complex system dynamics associated with highly separated flow effects together with nonlinear coupling between aeroelastic modes. Bifurcations to the nonlinear aeroelastic system are observed for two investigations, that is, considering oscillations-induced aeroelastic evolutions with varying freestream speed, and aeroelastic evolutions at constant freestream speed and varying oscillations. Finally, Lyapunov exponent calculation is proceeded in order to infer on chaotic behavior. Poincaré mappings also suggest bifurcations and chaos, reinforced by the attainment of maximum positive Lyapunov exponents.

  8. Nuclear turbine efficiency improvement by wet steam study

    International Nuclear Information System (INIS)

    Nishikawa, Tsuyoshi; Morson, A.; Markytan, R.

    2000-01-01

    Most of the turbine used at the nuclear power plant are operated at environment of wet steam, which composes of a big factor of its inner loss in comparison with those of the thermal power plant. If an analytical method predictable on behavior of the wet steam is established, it could be upgraded efficiency of the turbine and also reliability against corrosion formed by moisture. This study, therefore, aims at understanding of physical property of the wet steam flow scarcely known at present, development of an optimum turbine cascade design tool reflected by the property, development of a turbine cascade design reducible of steam loss due to wet steam by using the tool, and development on a method of removing moisture in the turbine to its outer portion. For the tool, a new three dimensional flow numerical analysis is necessary to be developed, to aim at accurately and numerically understanding of the behavior of wet steam. As this study is in advancing now, by using a turbine cascade optimized on the wet steam flow and a developed moisture removing apparatus, about 0.6 % of upgrading in turbine efficiency can be predicted in comparison with that of the advanced aero-cascade of the GE Corporation. (G.K.)

  9. Analysis of the effect of curtailment on power and fatigue loads of two aligned wind turbines using an actuator disc approach

    International Nuclear Information System (INIS)

    Martinen, Silke; Nilsson, Karl; Breton, Simon-Philippe; Ivanell, Stefan; Carlén, Ingemar

    2014-01-01

    To study the effects of curtailment on both power production and fatigue loading, actuator disc (ACD) simulations of two turbines aligned in the wind direction are performed with the EllipSys3D code developed at DTU/Risø. A simple non-aeroelastic fatigue load evaluation method for ACD simulations is developed. Blade loads, extracted along a line that rotates in the rotor plane with the rotational velocity of the respective turbine, are used to calculate flapwise bending moments. After applying a rainflow counting algorithm an equivalent moment is calculated. Power curtailment is introduced by increasing the blade pitch angle of the first turbine. Evaluation is made with regards to fatigue load reduction at the second turbine and the change in the total production. Further parameters investigated are the spacing between the two turbines and the level of imposed pre-generated turbulence. The aeroelastic code Vidyn, Ganander [1], is used for validation of the ACD load evaluation method. For this purpose, the EllipSys3D simulations are rerun without the second turbine. Time series of cross sectional velocity fields are extracted at positions corresponding to the former placement of the downstream turbine and used as input for aeroelastic turbine load calculations in Vidyn. The results from Vidyn and the results based on the ACD loads show similar trends. Fatigue loads at the downwind turbine are clearly decreasing as the blade pitch angle of the upstream turbine is increasing. The achievable amount of fatigue load reduction depends on the level of the imposed pre-generated turbulence as well as the spacing between the turbines. The presented method is intended for further development of wind park optimization strategies

  10. An integrated modeling method for wind turbines

    Science.gov (United States)

    Fadaeinedjad, Roohollah

    To study the interaction of the electrical, mechanical, and aerodynamic aspects of a wind turbine, a detailed model that considers all these aspects must be used. A drawback of many studies in the area of wind turbine simulation is that either a very simple mechanical model is used with a detailed electrical model, or vice versa. Hence the interactions between electrical and mechanical aspects of wind turbine operation are not accurately taken into account. In this research, it will be shown that a combination of different simulation packages, namely TurbSim, FAST, and Simulink can be used to model the aerodynamic, mechanical, and electrical aspects of a wind turbine in detail. In this thesis, after a review of some wind turbine concepts and software tools, a simulation structure is proposed for studying wind turbines that integrates the mechanical and electrical components of a wind energy conversion device. Based on the simulation structure, a comprehensive model for a three-bladed variable speed wind turbine with doubly-fed induction generator is developed. Using the model, the impact of a voltage sag on the wind turbine tower vibration is investigated under various operating conditions such as power system short circuit level, mechanical parameters, and wind turbine operating conditions. It is shown how an electrical disturbance can cause more sustainable tower vibrations under high speed and turbulent wind conditions, which may disrupt the operation of pitch control system. A similar simulation structure is used to model a two-bladed fixed speed wind turbine with an induction generator. An extension of the concept is introduced by adding a diesel generator system. The model is utilized to study the impact of the aeroelastic aspects of wind turbine (i.e. tower shadow, wind shears, yaw error, turbulence, and mechanical vibrations) on the power quality of a stand-alone wind-diesel system. Furthermore, an IEEE standard flickermeter model is implemented in a

  11. Study of composite wind turbine spars

    Science.gov (United States)

    Zafar, Syed Shahrukh

    This report presents a theoretical, numerical and experimental study of composite wind turbine spars under bending loads. Spars were made from commercially available glass/ carbon fiber material. The spars were composed of uniaxial (0°) flanges and biaxial (+/-45°) shear webs. Items of particular study were co-block polymer additives in vinyl ester resins, a presumably new spar design, and using carbon fiber pultrusions for spar caps (flanges). Composites are very strong and thus tend to be thin, which exacerbates the problem of buckling. Further, fibers also buckle at the micro level, leading to lower effective compression strength than tensile strength of a composite. Many structures tend to buckle in out of plane direction which can cause early and abrupt failure. A 3-point bend test rig was manufactured in-house for experimentally testing composite spars. The experiments indicated abrupt failure without any sign or other form of damage. Limited number of spars was made with slightly different construction. All spars were subjected to same testing environment. Finite element analyses were performed in order to shed light on the failure mechanisms leading to catastrophic failure. The FE code Ansys was used for the analyses. 3D models were developed, loads were applied, and linear elastic static as well as buckling analyses were performed. The results obtained from analysis were in reasonable agreement with the experimental tests.

  12. KNOW-BLADE task-4 report: Navier-Stokes aeroelasticity

    DEFF Research Database (Denmark)

    Politis, E.S.; Nikolaou, I.G.; Chaviaropoulos, P.K.

    2004-01-01

    The problem of the aeroelastic stability of wind turbine blades is addressed in this report by advancing the aerodynamic modelling in the beam element type codes from the engineering-type empirical models to unsteady, 2D or 3D, Navier-Stokes solvers. Inthis project, structural models for the full...... wind turbine blade have been combined with 2D and 3D unsteady Navier-Stokes solvers. The relative disadvantage of the quasi-3D approach (where the elastic solver is coupled with a 2D Navier-Stokes solver) isits inability to model induced flow. The lack of a validation test case did not allow...

  13. Fuel cell/gas turbine system performance studies

    Energy Technology Data Exchange (ETDEWEB)

    Lee, G.T.; Sudhoff, F.A.

    1996-12-31

    Because of the synergistic effects (higher efficiencies, lower emissions) of combining a fuel cell and a gas turbine into a power generation system, many potential system configurations were studied. This work is focused on novel power plant systems by combining gas turbines, solid oxide fuel cells, and a high-temperature heat exchanger; these systems are ideal for the distributed power and on- site markets in the 1-5 MW size range.

  14. Study on wind turbine arrangement for offshore wind farms

    DEFF Research Database (Denmark)

    Shen, Wen Zhong; Mikkelsen, Robert Flemming

    2011-01-01

    In this paper, the separation distance between two neighboring offshore wind turbines has been carried out by using the Actuator Line/Navier-Stokes technique developed at the Technical University of Denmark (DTU). Under offshore atmospheric conditions, Large Eddy Simulation has been performed for...... to the turbulence mixing. This study hints that the optimal separation distance between neighboring turbines for offshore wind farms should be 7 rotor diameters....

  15. NEXT GENERATION GAS TURBINE (NGGT) SYSTEMS STUDY

    Energy Technology Data Exchange (ETDEWEB)

    Unknown

    2001-12-05

    Building upon the 1999 AD Little Study, an expanded market analysis was performed by GE Power Systems in 2001 to quantify the potential demand for an NGGT product. This analysis concluded that improvements to the US energy situation might be best served in the near/mid term (2002-2009) by a ''Technology-Focused'' program rather than a specific ''Product-Focused'' program. Within this new program focus, GEPS performed a parametric screening study of options in the three broad candidate categories of gas turbines: aero-derivative, heavy duty, and a potential hybrid combining components of the other two categories. GEPS's goal was to determine the best candidate systems that could achieve the DOE PRDA expectations and GEPS's internal design criteria in the period specified for initial product introduction, circa 2005. Performance feasibility studies were conducted on candidate systems selected in the screening task, and critical technology areas were identified where further development would be required to meet the program goals. DOE PRDA operating parameters were found to be achievable by 2005 through evolutionary technology. As a result, the study was re-directed toward technology enhancements for interim product introductions and advanced/revolutionary technology for potential NGGT product configurations. Candidate technologies were identified, both evolutionary and revolutionary, with a potential for possible development products via growth step improvements. Benefits were analyzed from two perspectives: (1) What would be the attributes of the top candidate system assuming the relevant technologies were developed and available for an NGGT market opportunity in 2009/2010; and (2) What would be the expected level of public benefit, assuming relevant technologies were incorporated into existing new and current field products as they became available. Candidate systems incorporating these technologies were assessed as

  16. Influence of Icing on the Modal Behavior of Wind Turbine Blades

    Directory of Open Access Journals (Sweden)

    Sudhakar Gantasala

    2016-10-01

    Full Text Available Wind turbines installed in cold climate sites accumulate ice on their structures. Icing of the rotor blades reduces turbine power output and increases loads, vibrations, noise, and safety risks due to the potential ice throw. Ice accumulation increases the mass distribution of the blade, while changes in the aerofoil shapes affect its aerodynamic behavior. Thus, the structural and aerodynamic changes due to icing affect the modal behavior of wind turbine blades. In this study, aeroelastic equations of the wind turbine blade vibrations are derived to analyze modal behavior of the Tjaereborg 2 MW wind turbine blade with ice. Structural vibrations of the blade are coupled with a Beddoes-Leishman unsteady attached flow aerodynamics model and the resulting aeroelastic equations are analyzed using the finite element method (FEM. A linearly increasing ice mass distribution is considered from the blade root to half-length and thereafter constant ice mass distribution to the blade tip, as defined by Germanischer Lloyd (GL for the certification of wind turbines. Both structural and aerodynamic properties of the iced blades are evaluated and used to determine their influence on aeroelastic natural frequencies and damping factors. Blade natural frequencies reduce with ice mass and the amount of reduction in frequencies depends on how the ice mass is distributed along the blade length; but the reduction in damping factors depends on the ice shape. The variations in the natural frequencies of the iced blades with wind velocities are negligible; however, the damping factors change with wind velocity and become negative at some wind velocities. This study shows that the aerodynamic changes in the iced blade can cause violent vibrations within the operating wind velocity range of this turbine.

  17. Numerical simulation of the divergence of a wind turbine airfoil : part 2

    Energy Technology Data Exchange (ETDEWEB)

    Ramdenee, D.; Minea, I.S.; Tardiff d' Hamonville, T.; Illinca, A. [Quebec Univ., Rimouski, PQ (Canada). Laboratoire de Recherche en Energie Eolienne

    2010-07-01

    The development of larger, more flexible wind turbine blades is creating the need for an improved understanding of the mechanisms surrounding unsteady flow-structure interactions. This 2-part study used computational fluid dynamics (CFD) to identify and model the aerodynamic and aeroelastic phenomena around wind turbine blades. Aeroelastic divergence was modelled using coupled aerodynamic and elastic models with an ANSYS software program. The fluid-structure interactions of an NACA0012 airfoil were simulated in order to determine the divergence phenomenon created by aerodynamic loads and transient fluid flow. The airfoil profile was fixed and exempted from all rotational degrees of liberty while being subjected to a constant flow of velocity. The fixing was then removed and the constant flow was compared with a shock wave on the airfoil profile. The profile then oscillated with damped amplitude due to the aerodynamic damping imposed. Results of the analysis will be compared with results obtained in future studies. 7 refs., 2 tabs., 6 figs.

  18. An investigation on wind turbine resonant vibrations

    DEFF Research Database (Denmark)

    Tibaldi, Carlo; Kim, Taeseong; Larsen, Torben J.

    2016-01-01

    Wind turbine resonant vibrations are investigated based on aeroelastic simulations both in frequency and time domain. The investigation focuses on three different aspects: the need of a precise modeling when a wind turbine is operating close to resonant conditions; the importance of estimating wind...... turbine loads also at low turbulence intensity wind conditions to identify the presence of resonances; and the wind turbine response because of external excitations. In the first analysis, three different wind turbine models are analysed with respect to the frequency and damping of the aeroelastic modes....... Fatigue loads on the same models are then investigated with two different turbulence intensities to analyse the wind turbine response. In the second analysis, a wind turbine model is excited with an external force. This analysis helps in identifying the modes that might be excited, and therefore...

  19. A Two-Bladed Concept Wind Turbine

    DEFF Research Database (Denmark)

    Kim, Taeseong

    2012-01-01

    This article shows the potential for reducing extreme loads with an innovative design of wind turbine, a partial pitch two-bladed concept turbine. The most extreme conditions to test a turbine are considered to be stand-still combined with a grid failure in which the wind comes from all directions...... from 0 to 360 degrees. All aeroelastic load simulations are done by using the aeroelastic code HAWC2. From the load comparisons between the partial pitch two-bladed turbine and a conventional three-bladed turbine it is observed that the partial pitch two-bladed turbine can reduce the extreme tower...... bottom bending moment by approximately 33% compared to the three-bladed turbine....

  20. On the way to reliable aeroelastic load simulation on VAWT's

    DEFF Research Database (Denmark)

    Larsen, Torben J.; Aagaard Madsen, Helge

    2013-01-01

    In this paper a method for an implementation of a 2D actuator cylinder flow model of an Vertical Axis Wind Turbine (VAWT) is presented. The model is implemented in a full aeroelastic code including consideration of structural dynamics, dynamic inflow, tower shadow and dynamic stall, which is needed...... for a full load analysis relating to eg. certification of a VAWT turbine. Further on, principal load cases according to the IEC61400-1 are simulated for a fictitious 5MW VAWT turbine in it’s simplest 2 bladed Darrieus configuration. The IEC61400-1 load cases, originally developed for Horizontal Axis Wind...... Turbines (HAWT’s), are discussed regarding the application to VAWT’s. Further on a small section regarding aerodynamic flow in curved motion is included....

  1. Flow studies in a wet steam turbine

    Science.gov (United States)

    Evans, D. H.; Pouchot, W. D.

    1974-01-01

    The design and test results of a four stage wet vapor turbine operating with slightly superheated inlet steam and expanding to 10% exit moisture are presented. High speed movies at 3000 frames per second of liquid movement on the pressure side and along the trailing edge of the last stator blade are discussed along with back lighted photographs of moisture drops as they were torn from the stator blade trailing edge. Movies at lower framing rates were also taken of the exit of the last rotating blade and the casing moisture removal slot located in line with the rotor blade shroud. Also moisture removal data are presented of casing slot removal at the exit of the third and fourth rotor blades and for slots located in the trailing edge of the last stator blade. Finally, the degradation of turbine thermodynamic performance due to condensation formation and movement is discussed.

  2. Numerical simulation of a wind turbine airfoil : part 1

    Energy Technology Data Exchange (ETDEWEB)

    Ramdenee, D.; Minea, I.S.; Tardiff d' Hamonville, T.; Illinca, A. [Quebec Univ., Rimouski, PQ (Canada). Laboratoire de Recherche en Energie Eolienne

    2010-07-01

    This 2-part study used computational fluid dynamics (CFD) to identify and model the aerodynamic and aeroelastic phenomena around wind turbine blades. The aim of the study was to better understand the mechanisms surrounding unsteady flow-structure interactions. Aerodynamic and elastic models were coupled using an ANSYS multi-domain program to simulate the aeroelastic divergence of a typical section airfoil with a single rotational structural degree of freedom. Solvers were used to realize a sequence of multi-domain time steps and coupling iterations between time steps. Each element of the airfoil was divided into interpolation faces which were then transformed into 2-D polygons. An intersection process was used to create a large number of control surfaces that were used to study interactions between the structural and fluid domains. The calculations were used to determine the divergence speed and Eigen modes of vibration. A literature review was also included. 19 refs., 7 figs.

  3. Study of the feasibility aspects of flight testing an aeroelastically tailored forward swept research wing on a BQM-34F drone vehicle

    Science.gov (United States)

    Mourey, D. J.

    1979-01-01

    The aspects of flight testing an aeroelastically tailored forward swept research wing on a BQM-34F drone vehicle are examined. The geometry of a forward swept wing, which is incorporated into the BQM-34F to maintain satisfactory flight performance, stability, and control is defined. A preliminary design of the aeroelastically tailored forward swept wing is presented.

  4. The Simulation Study of Horizontal Axis Water Turbine Using Flow Simulation Solidworks Application

    Science.gov (United States)

    Prasetyo, H.; Budiana, EP; Tjahjana, DDDP; Hadi, S.

    2018-02-01

    The design of Horizontal Axis Water Turbine in pico hydro power plants involves many parameters. To simplify that, usually using computer simulation is applied. This research performs simulation process variation on turbine blade number, turbine blade curvature angle, turbine bucket angle and blocking system tilt angle. Those four variations were combined in order to obtain the best design of turbine. The study used Flow Simulation Solidworks application, and obtain data on turbine speed, pressure, force, and torque. However, this research focused on turbine torque value. The best design of turbine was obtained in the turbine with 6 blades, blade curvature angle of 65° and bucket angle of 10°, and blocking system tilt angle of 40°. In the best turbine, the produced torque value was 8.464 Nm.

  5. Generator dynamics in aeroelastic analysis and simulations

    DEFF Research Database (Denmark)

    Larsen, Torben J.; Hansen, Morten Hartvig; Iov, F.

    2003-01-01

    This report contains a description of a dynamic model for a doubly-fed induction generator. The model has physical input parameters (voltage, resistance, reactance etc.) and can be used to calculate rotor and stator currents, hence active and reactivepower. A perturbation method has been used...... to reduce the original generator model equations to a set of equations which can be solved with the same time steps as a typical aeroelastic code. The method is used to separate the fast transients of the modelfrom the slow variations and deduce a reduced order expression for the slow part. Dynamic effects...... of the first order terms in the model as well as the influence on drive train eigenfrequencies and damping has been investigated. Load response during timesimulation of wind turbine response have been compared to simulations with a traditional static generator model based entirely on the slip angle. A 2 MW...

  6. Recent advance in nonlinear aeroelastic analysis and control of the aircraft

    Directory of Open Access Journals (Sweden)

    Xiang Jinwu

    2014-02-01

    Full Text Available A review on the recent advance in nonlinear aeroelasticity of the aircraft is presented in this paper. The nonlinear aeroelastic problems are divided into three types based on different research objects, namely the two dimensional airfoil, the wing, and the full aircraft. Different nonlinearities encountered in aeroelastic systems are discussed firstly, where the emphases is placed on new nonlinear model to describe tested nonlinear relationship. Research techniques, especially new theoretical methods and aeroelastic flutter control methods are investigated in detail. The route to chaos and the cause of chaotic motion of two-dimensional aeroelastic system are summarized. Various structural modeling methods for the high-aspect-ratio wing with geometric nonlinearity are discussed. Accordingly, aerodynamic modeling approaches have been developed for the aeroelastic modeling of nonlinear high-aspect-ratio wings. Nonlinear aeroelasticity about high-altitude long-endurance (HALE and fight aircrafts are studied separately. Finally, conclusions and the challenges of the development in nonlinear aeroelasticity are concluded. Nonlinear aeroelastic problems of morphing wing, energy harvesting, and flapping aircrafts are proposed as new directions in the future.

  7. Aeroelasticity of morphing wings using neural networks

    Science.gov (United States)

    Natarajan, Anand

    In this dissertation, neural networks are designed to effectively model static non-linear aeroelastic problems in adaptive structures and linear dynamic aeroelastic systems with time varying stiffness. The use of adaptive materials in aircraft wings allows for the change of the contour or the configuration of a wing (morphing) in flight. The use of smart materials, to accomplish these deformations, can imply that the stiffness of the wing with a morphing contour changes as the contour changes. For a rapidly oscillating body in a fluid field, continuously adapting structural parameters may render the wing to behave as a time variant system. Even the internal spars/ribs of the aircraft wing which define the wing stiffness can be made adaptive, that is, their stiffness can be made to vary with time. The immediate effect on the structural dynamics of the wing, is that, the wing motion is governed by a differential equation with time varying coefficients. The study of this concept of a time varying torsional stiffness, made possible by the use of active materials and adaptive spars, in the dynamic aeroelastic behavior of an adaptable airfoil is performed here. Another type of aeroelastic problem of an adaptive structure that is investigated here, is the shape control of an adaptive bump situated on the leading edge of an airfoil. Such a bump is useful in achieving flow separation control for lateral directional maneuverability of the aircraft. Since actuators are being used to create this bump on the wing surface, the energy required to do so needs to be minimized. The adverse pressure drag as a result of this bump needs to be controlled so that the loss in lift over the wing is made minimal. The design of such a "spoiler bump" on the surface of the airfoil is an optimization problem of maximizing pressure drag due to flow separation while minimizing the loss in lift and energy required to deform the bump. One neural network is trained using the CFD code FLUENT to

  8. Aeroelastic research programme EFP-2001[YAW;STALL]; Forskning i aeroelasticitet EFP-2001

    Energy Technology Data Exchange (ETDEWEB)

    Aagaard Madsen, H. (ed.)

    2002-12-01

    The project covers the one year period from mid 2001 to mid 2002 and is the last part of a 5 years research programme on aeroelasticity. The overall objectives of the project are to improve the load and design basis for wind turbines and to ensure in collaboration with industry a continu-ously running process on development of new designs and solution of actual problems. Specifi-cally the main objectives for the present period are the following: a) development of a design tool for analysis of dynamic stability b) investigations of blade tip aerodynamics and blade tip design on basis of 3D CFD computa-tions c) publication of an airfoil catalogue d) load reduction using new control strategies e) aeroacoustic modelling of noise propagation During the present project period the computer code HAWCModal has been finished. The code computes the modal characteristics for a turbine as function of rotational speed. It is based on the structural modelling in the aeroelastic code HAWC and uses the same input files. The computed eigen frequencies are shown in a Campbell diagram and the corresponding modal forms can be shown graphically for an operating turbine. Finally, the structural damping is also computed by the code. HAWCModal is the basis for the stability analysis tool HAWCStab which is now under devel-opment. With HAWCStab the aeroelastic stability of a turbine can be analysed. The complex aerodynamics at three different blade tip shapes have been analysed with the three-dimensional CFD code EllipSys3D. The tip vortex was visualised and the lift and drag coef-ficients in the tip region were analysed in order to study the influence of the tip geometry on the performance and aerodynamic damping. An airfoil catalogue containing computations on 28 different airfoils for wind turbine applica-tion in comparison with experimental data has been developed and is available via the internet. Besides the main themes of the project as mentioned above there have been research

  9. Investigations on precursor measures for aeroelastic flutter

    Science.gov (United States)

    Venkatramani, J.; Sarkar, Sunetra; Gupta, Sayan

    2018-04-01

    Wind tunnel experiments carried out on a pitch-plunge aeroelastic system in the presence of fluctuating flows reveal that flutter instability is presaged by a regime of intermittency. It is observed that as the flow speed gradually increases towards the flutter speed, there appears intermittent bursts of periodic oscillations which become more frequent as the wind speed increases and eventually the dynamics transition into fully developed limit cycle oscillations, marking the onset of flutter. The signature from these intermittent oscillations are exploited to develop measures that forewarn a transition to flutter and can serve as precursors. This study investigates a suite of measures that are obtained directly from the time history of measurements and are hence model independent. The dependence of these precursors on the size of the measured data set and the time required for their computation is investigated. These measures can be useful in structural health monitoring of aeroelastic structures.

  10. Indicial lift response function: an empirical relation for finite‐thickness airfoils, and effects on aeroelastic simulations

    DEFF Research Database (Denmark)

    Bergami, Leonardo; Gaunaa, Mac; Heinz, Joachim Christian

    2013-01-01

    The aeroelastic response of wind turbines is often simulated in the time domain by using indicial response techniques. Unsteady aerodynamics in attached flow are usually based on Jones's approximation of the flat plate indicial response, although the response for finite‐thickness airfoils differs...... of equivalent fatigue loads, ultimate loads, and stability limits. The agreement with CFD computations of a 2D profile in harmonic motion is improved by the indicial function accounting for the finite‐thickness of the airfoil. Concerning the full wind turbine aeroelastic behavior, the differences between...... profile undergoing harmonic pitching motion in the attached flow region; the resulting lift forces are compared with computational fluid dynamics (CFD) simulations. The relevance for aeroelastic simulations of a wind turbine is also evaluated, and the effects are quantified in terms of variations...

  11. Small Wind Research Turbine: Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Corbus, D.; Meadors, M.

    2005-10-01

    The Small Wind Research Turbine (SWRT) project was initiated to provide reliable test data for model validation of furling wind turbines and to help understand small wind turbine loads. This report will familiarize the user with the scope of the SWRT test and support the use of these data. In addition to describing all the testing details and results, the report presents an analysis of the test data and compares the SWRT test data to simulation results from the FAST aeroelastic simulation model.

  12. Wind tunnel tests of a free yawing downwind wind turbine

    Science.gov (United States)

    Verelst, D. R. S.; Larsen, T. J.; van Wingerden, J. W.

    2014-12-01

    This research paper presents preliminary results on a behavioural study of a free yawing downwind wind turbine. A series of wind tunnel tests was performed at the TU Delft Open Jet Facility with a three bladed downwind wind turbine and a rotor radius of 0.8 meters. The setup includes an off the shelf three bladed hub, nacelle and generator on which relatively flexible blades are mounted. The tower support structure has free yawing capabilities provided at the base. A short overview on the technical details of the experiment is given as well as a brief summary of the design process. The discussed test cases show that the turbine is stable while operating in free yawing conditions. Further, the effect of the tower shadow passage on the blade flapwise strain measurement is evaluated. Finally, data from the experiment is compared with preliminary simulations using DTU Wind Energy's aeroelastic simulation program HAWC2.

  13. Aeroelastic modelling without the need for excessive computing power

    Energy Technology Data Exchange (ETDEWEB)

    Infield, D. [Loughborough Univ., Centre for Renewable Energy Systems Technology, Dept. of Electronic and Electrical Engineering, Loughborough (United Kingdom)

    1996-09-01

    The aeroelastic model presented here was developed specifically to represent a wind turbine manufactured by Northern Power Systems which features a passive pitch control mechanism. It was considered that this particular turbine, which also has low solidity flexible blades, and is free yawing, would provide a stringent test of modelling approaches. It was believed that blade element aerodynamic modelling would not be adequate to properly describe the combination of yawed flow, dynamic inflow and unsteady aerodynamics; consequently a wake modelling approach was adopted. In order to keep computation time limited, a highly simplified, semi-free wake approach (developed in previous work) was used. a similarly simple structural model was adopted with up to only six degrees of freedom in total. In order to take account of blade (flapwise) flexibility a simple finite element sub-model is used. Good quality data from the turbine has recently been collected and it is hoped to undertake model validation in the near future. (au)

  14. Aeroelastic Stability of a 2D Airfoil Section equipped with a Trailing Edge Flap

    DEFF Research Database (Denmark)

    Bergami, Leonardo

    Recent studies conclude that important reduction of the fatigue loads encountered by a wind turbine blade can be achieved using a deformable trailing edge control system. The focus of the current work is to determine the effect of this flap-like system on the aeroelastic stability of a 2D airfoil...... section. A simulation tool is implemented to predict the flow speed at which a flap equipped section may become unstable, either due to flutter or divergence. First, the stability limits of the airfoil without flap are determined, and, in the second part of the work, a deformable trailing edge flap...... is applied. Stability is investigated for the uncontrolled flap, and for three different control algorithms. The three controls are tuned for fatigue load alleviation and they are based on, respectively, measurement of the heave displacement and velocity, measurement of the local angle of attack, measurement...

  15. System design and optimization study of axial flow turbine applied in ...

    Indian Academy of Sciences (India)

    Home; Journals; Sadhana; Volume 40; Issue 8. System design and optimization study of axial flow turbine applied in an overtopping wave energy convertor ... To study the rules between parameters of the turbine and flows, three different types of turbines with complete 3D flow-channel models were designed and optimized.

  16. Study on an Axial Flow Hydraulic Turbine with Collection Device

    Directory of Open Access Journals (Sweden)

    Yasuyuki Nishi

    2014-01-01

    Full Text Available We propose a new type of portable hydraulic turbine that uses the kinetic energy of flow in open channels. The turbine comprises a runner with an appended collection device that includes a diffuser section in an attempt to improve the output by catching and accelerating the flow. With such turbines, the performance of the collection device, and a composite body comprising the runner and collection device were studied using numerical analysis. Among four stand-alone collection devices, the inlet velocity ratio was most improved by the collection device featuring an inlet nozzle and brim. The inlet velocity ratio of the composite body was significantly lower than that of the stand-alone collection device, owing to the resistance of the runner itself, the decreased diffuser pressure recovery coefficient, and the increased backpressure coefficient. However, at the maximum output tip speed ratio, the inlet velocity ratio and the loading coefficient were approximately 31% and 22% higher, respectively, for the composite body than for the isolated runner. In particular, the input power coefficient significantly increased (by approximately 2.76 times owing to the increase in the inlet velocity ratio. Verification tests were also conducted in a real canal to establish the actual effectiveness of the turbine.

  17. Study of applying reverse engineering to turbine blade manufacture

    International Nuclear Information System (INIS)

    She, Chen Hua; Chang, Chun Chi

    2007-01-01

    A turbine blade has complex shaped free-form surfaces that can be modelled as surfaces with variable curvature by high-degree polynomials. Industry typically utilizes a turnkey system and special-purpose machine tool to manufacture turbine blades. A turkey system is a closed form design. Users need only input relevant data to this system to manufacture the product directly. However, users are unaware of the internal operation of the system. With rapidly advances in computing technology, commercial CAD/CAM systems can be utilized to design freeform surfaces and generate a tool path for the designed surfaces. This study uses a reverse engineering technology that is used to reconstruct the CAD model for a turbine blade. The prototype is measured by a coordinate measuring machine to obtain the geometrical control data points that are used to generate the CAD model in the UniGraphics (UG) CAD/CAM system. The UG/GRIP (GRaphics interactive Programming) language is used to generate the cutter location data rather than using the default UG CAM module. A five-axis NC code is acquired by the developed postprocessor and verified by the solid cutting simulation software VERICUT. Real turbine blade machining is performed on a table/spindle tilting five-axis machine tool, demonstrating the effectiveness of the proposed approach

  18. Multibody Model for Planetary Gearbox of 500 kW Wind Turbine

    DEFF Research Database (Denmark)

    Jørgensen, Martin Felix; Pedersen, Niels Leergaard; Sørensen, Jens Nørkær

    The aim of the work is to simulate the loadings in a planetary gearbox of a wind turbine using a multibody program. A realistic wind turbine gearbox of a 500 kW wind turbine is examined using turbulent inflow data. An aeroelastic model of the wind turbine has been set up using the FLEX5-code...... (industrial standard software). The FLEX5 model as well as the developed multibody code has been verified from strain gauge measurements, giving e.g. the main shaft torque, and met mast wind data measurements. The realistic measurements on both input and output variables form an excellent base for studying...... the gearbox fatigue loads, the effect of wind turbulence on the power production/output torque on the highspeed shaft and for calibration and verification of the gearbox model....

  19. Study of turbine and guide vanes integration to enhance the performance of cross flow vertical axis wind turbine

    Science.gov (United States)

    Wibowo, Andreas; Tjahjana, Dominicus Danardono Dwi Prija; Santoso, Budi; Situmorang, Marcelinus Risky Clinton

    2018-02-01

    The main purpose of this study is to investigate the best configuration between guide vanes and cross flow vertical axis wind turbine with variation of several parameters including guide vanes tilt angle and the number of turbine and guide vane blades. The experimental test were conducted under various wind speed and directions for testing cross flow wind turbine, consisted of 8, 12 and 16 blades. Two types of guide vane were developed in this study, employing 20° and 60° tilt angle. Both of the two types of guide vane had three variations of blade numbers which had same blade numbers variations as the turbines. The result showed that the configurations between 60° guide vane with 16 blade numbers and turbine with 16 blade numbers had the best configurations. The result also showed that for certain configuration, guide vane was able to increase the power generated by the turbine significantly by 271.39% compared to the baseline configuration without using of guide vane.

  20. NRT Rotor Structural / Aeroelastic Analysis for the Preliminary Design Review

    Energy Technology Data Exchange (ETDEWEB)

    Ennis, Brandon Lee [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Paquette, Joshua A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-10-01

    This document describes the initial structural design for the National Rotor Testbed blade as presented during the preliminary design review at Sandia National Laboratories on October 28- 29, 2015. The document summarizes the structural and aeroelastic requirements placed on the NRT rotor for satisfactory deployment at the DOE/SNL SWiFT experimental facility to produce high-quality datasets for wind turbine model validation. The method and result of the NRT blade structural optimization is also presented within this report, along with analysis of its satisfaction of the design requirements.

  1. Aeroelastic Tailoring of Transport Aircraft Wings: State-of-the-Art and Potential Enabling Technologies

    Science.gov (United States)

    Jutte, Christine; Stanford, Bret K.

    2014-01-01

    This paper provides a brief overview of the state-of-the-art for aeroelastic tailoring of subsonic transport aircraft and offers additional resources on related research efforts. Emphasis is placed on aircraft having straight or aft swept wings. The literature covers computational synthesis tools developed for aeroelastic tailoring and numerous design studies focused on discovering new methods for passive aeroelastic control. Several new structural and material technologies are presented as potential enablers of aeroelastic tailoring, including selectively reinforced materials, functionally graded materials, fiber tow steered composite laminates, and various nonconventional structural designs. In addition, smart materials and structures whose properties or configurations change in response to external stimuli are presented as potential active approaches to aeroelastic tailoring.

  2. Aeroelastic Wingbox Stiffener Topology Optimization

    Science.gov (United States)

    Stanford, Bret K.

    2017-01-01

    This work considers an aeroelastic wingbox model seeded with run-out blade stiffeners along the skins. Topology optimization is conducted within the shell webs of the stiffeners, in order to add cutouts and holes for mass reduction. This optimization is done with a global-local approach in order to moderate the computational cost: aeroelastic loads are computed at the wing-level, but the topology and sizing optimization is conducted at the panel-level. Each panel is optimized separately under stress, buckling, and adjacency constraints, and periodically reassembled to update the trimmed aeroelastic loads. The resulting topology is baselined against a design with standard full-depth solid stiffener blades, and found to weigh 7.43% less.

  3. Study of cooling effectiveness for an integrated cooling turbine blade

    OpenAIRE

    Matsushita, Masahiro; Yamane, Takashi; Mimura, Fujio; Fukuyama, Yoshitaka; 松下 政裕; 山根 敬; 三村 富嗣雄; 福山 佳孝

    2007-01-01

    Experimental study of film cooling, impingement cooling and integrated cooling were carried out with the aim of applying them to turbine cooling. The experiments were conducted with 673 K hot gas flow and room temperature cooling air. Test plate surface temperature distributions were measured with an infrared camera. This report presents fundamental research data on cooling performance of the test plates for the validation of numerical simulation. Moreover, simplify heat transfer calculations...

  4. Application of a three-dimensional aeroelastic model to study the wind-induced response of bridge stay cables in unsteady wind conditions

    Science.gov (United States)

    Raeesi, Arash; Cheng, Shaohong; Ting, David S.-K.

    2016-08-01

    The possibility of bridge stay cables experiencing violent dry inclined cable galloping raises great concern in the engineering community. Numerous experimental and analytical studies have been conducted to investigate this phenomenon, most of which were in the context of steady wind past a rigid cylindrical body. Real stay cables however, are generally long and flexible. They are exposed to more "broad" range of atmospheric boundary layer type of wind velocity profile which is also unsteady and turbulent by nature. To better understand the physics underlying this type of wind-induced cable vibration and to elucidate various contributing factors, a more realistic analytical model which is capable of addressing the above elements is imperative. In the current paper, a three-dimensional aeroelastic model is proposed to study the aerodynamic response of an inclined and/or yawed slender flexible cylindrical body subjected to unsteady mean wind, with practical application to wind-induced vibrations of bridge stay cables under no precipitation condition. The non-linear aerodynamic forces derived in the present study are combined with the cable free vibration equations available in literature to obtain the equations of motion for the wind-induced vibration of stay cables, which are solved numerically by an explicit finite difference scheme. The proposed three-dimensional aeroelastic model and numerical solution technique are validated by comparing the predicted cable free vibration responses with existing data in the literature. The mechanism which triggers dry inclined cable galloping and the required conditions for its growth are explored. In addition, the impact of different initial conditions and various unsteady mean wind scenarios on this violent cable motion are investigated. Results show that the occurrence of dry inclined cable galloping is associated with an opposite-phase relation between the relative wind speed and the aerodynamic force along the direction of

  5. Weldability studies in Cr-Mo-V turbine rotor steel

    International Nuclear Information System (INIS)

    Kim, G.S.; Indacochea, J.E.

    1988-01-01

    This study was undertaken to establish the weldability of a high pressure steam turbine rotor (1.0Cr-1.0Mo-0.25V steel). Characterization of the as-received material and subsequent evaluation of a de-embrittlement procedure suggests that such heat treatment should be carried out prior to welding. But the improvement in roughness experienced by the heat affected zone (HAZ) of welds produced on both as-received and de-embrittled steel coupons suggests that a preweld de-embrittlement treatment is unnecessary. Further, a postweld heat treatment (PWHT) at the optimum temperature was found to improve the impact properties of both the HAZ and the base metal. The welds were automatically made on steel coupons with the welding parameters held constant, controlled by a microprocessor. In terms of short-term mechanical properties, the turbine rotor can be weld repaired

  6. Controller Design Automation for Aeroservoelastic Design Optimization of Wind Turbines

    NARCIS (Netherlands)

    Ashuri, T.; Van Bussel, G.J.W.; Zaayer, M.B.; Van Kuik, G.A.M.

    2010-01-01

    The purpose of this paper is to integrate the controller design of wind turbines with structure and aerodynamic analysis and use the final product in the design optimization process (DOP) of wind turbines. To do that, the controller design is automated and integrated with an aeroelastic simulation

  7. Data Comparisons and Summary of the Second Aeroelastic Prediction Workshop

    Science.gov (United States)

    Heeg, Jennifer; Wieseman, Carol D.; Chwalowski, Pawel

    2016-01-01

    This paper presents the computational results generated by participating teams of the second Aeroelastic Prediction Workshop and compare them with experimental data. Aeroelastic and rigid configurations of the Benchmark Supercritical Wing (BSCW) wind tunnel model served as the focus for the workshop. The comparison data sets include unforced ("steady") system responses, forced pitch oscillations and coupled fluid-structure responses. Integrated coefficients, frequency response functions, and flutter onset conditions are compared. The flow conditions studied were in the transonic range, including both attached and separated flow conditions. Some of the technical discussions that took place at the workshop are summarized.

  8. Parametric study of turbine NGV blade lean and vortex design

    Directory of Open Access Journals (Sweden)

    Zhang Shaowen

    2016-02-01

    Full Text Available The effects of blade lean and vortex design on the aerodynamics of a turbine entry nozzle guide vane (NGV are considered using computational fluid dynamics. The aim of the work is to address some of the uncertainties which have arisen from previous studies where conflicting results have been reported for the effect on the NGV. The configuration was initially based on the energy efficient engine turbine which also served as the validation case for the computational method. A total of 17 NGV configurations were evaluated to study the effects of lean and vortex design on row efficiency and secondary kinetic energy. The distribution of mass flow ratio is introduced as an additional factor in the assessment of blade lean effects. The results show that in the turbine entry NGV, the secondary flow strength is not a dominant factor that determines NGV losses and therefore the changes of loading distribution due to blade lean and the associated loss mechanisms should be regarded as a key factor. Radial mass flow redistribution under different NGV lean and twist is demonstrated as an addition key factor influencing row efficiency.

  9. Design study on gas turbine high temperature reactor (GTHTR300)

    International Nuclear Information System (INIS)

    Kunitomi, Kazuhiko; Katanishi, Shoji; Takada, Shoji; Takizuka, Takakazu; Nakata, Tetsuo; Yan, Xing; Takei, Masanobu; Kosugiyama, Shinichi; Shiozawa, Shusaku

    2002-01-01

    Japan Atomic Energy Research Institute (JAERI) has been conducting the design study of an original design concept of gas turbine high temperature reactor, the GTHTR300 (Gas Turbine High Temperature Reactor 300). The GTHTR300 is a greatly simplified HTGR-GT plant that leads to substantially reduced technical and cost requirements for earlier technology deployment. Also, it is expected to be an efficient and economically competitive reactor in 2010s due to newly proposed design features such as core design with two-year refueling interval, conventional steel material usage for a reactor pressure vessel, innovative plant flow scheme and horizontally installed gas turbine unit. This paper describes the original design features focusing on reactor core design, fuel design, in-core structure design and reactor pressure vessel design. In addition, a preliminary cost evaluation proved that the capital cost of the GTHTR300 is less than a target cost of 200 thousands Yen/kWe. The present study is entrusted from the Ministry of Education, Culture, Sports, Science and Technology of Japan. (author)

  10. Research in aeroelasticity EFP-2007-II

    Energy Technology Data Exchange (ETDEWEB)

    Buhl, T. (ed.)

    2009-06-15

    This report contains results from the EFP-2007-II project 'Program for Research in Applied Aeroelasticity'. The main results can be summed up into the following bullets: 1) 2D CFD was used to investigate tower shadow effects on both upwind and downwind turbines, and was used to validate the tower shadow models implemented in the aeroelastic code HAWC2. 2) Using a streamlined tower reduces the tower shadow by 50% compared to a cylindrical tower. Similar reductions can be achieved using a four legged lattice tower. 3) The application of laminar/turbulent transition in CFD computations for airfoils is demonstrated. For attached flow over thin airfoils (18%) 2D computations provide good results while a combination of Detached Eddy Simulation and laminar/ turbulent transition modeling improve the results in stalled conditions for a thick airfoil. 4) The unsteady flow in the nacelle region of a wind turbine is dominated by large flow gradients caused by unsteady shedding of vortices from the root sections of the blades. 5) The averaged nacelle wind speed compares well to the freestream wind speed, whereas the nacelle flow angle is highly sensitive to vertical positioning and tilt in the inflow. 6) The trailing edge noise model, TNO, was implemented and validated. The results showed that the noise was not predicted accurately, but the model captured the trends and can be used in airfoil design. The model was implemented in the airfoil design tool AIRFOILOPT and existing airfoils can be adjusted to maintain the aerodynamic characteristics, but with reduced noise in the order of up to 3dB in total sound power level and up to 1dB with A-weighting. 7) 2D CFD simulations are performed to verify their capability in predicting multi element airfoil configurations. The present computations show good agreement with measured performance from wind tunnel experiments. 8) The stochastic fluctuations of the aerodynamic forces on blades in deep-stall have an insignificant

  11. Modeling of wind turbines for power system studies

    Energy Technology Data Exchange (ETDEWEB)

    Petru, T.

    2001-05-01

    When wind turbines are installed into the electric grid, the power quality is affected. Today, strict installation recommendations often prevail due to a lack of knowledge on this subject. Consequently, it is important to predict the impact of wind turbines on the electric grid before the turbines are installed. The thesis describes relevant power quality issues, discusses different configurations of wind turbines with respect to power quality and draw requirements regarding wind turbine modeling. A model of a stall-regulated, fixed-speed wind turbine system is introduced and its power quality impact on the electric grid is evaluated. The model is verified with field measurements.

  12. Load consequences when sweeping blades - A case study of a 5 MW pitch controlled wind turbine

    Energy Technology Data Exchange (ETDEWEB)

    Verelst, D.R.S.; Larsen, Torben J.

    2010-08-15

    The generic 5 MW NREL wind turbine model is used in Risoe's aeroelastic simulator HAWC2 to investigate 120 different swept blade configurations (forward and backward sweep). Sensitivity for 2 different controllers is considered as well. Backward sweep results in a pitch to feather torsional moment of the blade, effectively reducing blade twist angles under increased loading. This behaviour results in decreased flap-wise fatigue and extreme loads, an increase for edge-wise fatigue loading and status quo or slight decrease in extreme loads (depending on the controller). Tower base and shaft-end bending moments are reduced as well. Forward sweep leads to an increase in angle of attack under loading. For a pitch controlled turbine this leads to an increase in fatigue and extreme loading in all cases. A controller inflicted instability is present for the more extreme forward swept cases. Due to the shape of considered sweep curves, an inherent and significant increase in torsional blade root bending moment is noted. A boomerang shaped sweep curve is proposed to counteract this problematic increased loading. Controller sensitivity shows that adding sweep affects some loadings differently. Power output is reduced for backward sweep since the blade twist is optimized as a rigid structure, ignoring the torsional deformations which for a swept blade can be significant. (author)

  13. Some experiences in aircraft aeroelastic design using Preliminary Aeroelastic Design of Structures (PAD)

    Science.gov (United States)

    Radovcich, N. A.

    1984-01-01

    The design experience associated with a benchmark aeroelastic design of an out of production transport aircraft is discussed. Current work being performed on a high aspect ratio wing design is reported. The Preliminary Aeroelastic Design of Structures (PADS) system is briefly summarized and some operational aspects of generating the design in an automated aeroelastic design environment are discussed.

  14. Comparing Fatigue Life Estimations of Composite Wind Turbine Blades using different Fatigue Analysis Tools

    DEFF Research Database (Denmark)

    Ardila, Oscar Gerardo Castro; Lennie, Matthew; Branner, Kim

    2015-01-01

    In this paper, fatigue lifetime prediction of NREL 5MW reference wind turbine is presented. The fatigue response of materials used in selected blade cross sections was obtained by applying macroscopic fatigue approaches and assuming uniaxial stress states. Power production and parked load cases...... suggested by the IEC 61400-1 standard were studied employing different load time intervals and by using two novel fatigue tools called ALBdeS and BECAS+F. The aeroelastic loads were defined thought aeroelastic simulations performed with both FAST and HAWC2 tools. The stress spectra at each layer were...... calculated employing laminated composite theory and beam cross section methods. The Palmgren-Miner linear damage rule was used to calculate the accumulation damage. The theoretical results produced by both fatigue tools proved a prominent effect of analysed design load conditions on the estimated lifetime...

  15. Computational Fluid Dynamic (CFD) Study of an Articulating Turbine Blade Cascade

    Science.gov (United States)

    2016-11-01

    ARL-TR-7871 ● NOV 2016 US Army Research Laboratory Computational Fluid Dynamic (CFD) Study of an Articulating Turbine Blade...ARL-TR-7871 ● NOV 2016 US Army Research Laboratory Computational Fluid Dynamic (CFD) Study of an Articulating Turbine Blade Cascade by Luis...COVERED (From - To) 1 June–31 August 2016 4. TITLE AND SUBTITLE Computational Fluid Dynamic (CFD) Study of an Articulating Turbine Blade Cascade 5a

  16. Advanced turbine systems study system scoping and feasibility study

    Energy Technology Data Exchange (ETDEWEB)

    1993-04-01

    United Technologies Research Center, Pratt Whitney Commercial Engine Business, And Pratt Whitney Government Engine and Space Propulsion has performed a preliminary analysis of an Advanced Turbine System (ATS) under Contract DE-AC21-92MC29247 with the Morgantown Energy Technology Center. The natural gas-fired reference system identified by the UTC team is the Humid Air Turbine (HAT) Cycle in which the gas turbine exhaust heat and heat rejected from the intercooler is used in a saturator to humidify the high pressure compressor discharge air. This results in a significant increase in flow through the turbine at no increase in compressor power. Using technology based on the PW FT4000, the industrial engine derivative of the PW4000, currently under development by PW, the system would have an output of approximately 209 MW and an efficiency of 55.3%. Through use of advanced cooling and materials technologies similar to those currently in the newest generation military aircraft engines, a growth version of this engine could attain approximately 295 MW output at an efficiency of 61.5%. There is the potential for even higher performance in the future as technology from aerospace R D programs is adapted to aero-derivative industrial engines.

  17. Power Curves in a Wind Turbine Array: A Numerical Study

    DEFF Research Database (Denmark)

    Meyer Forsting, Alexander Raul

    The impact of measuring a power curve inside a wind turbine array is investigated using computational fluid dynamics. The array consists of five aligned rotors that yaw with the free-stream wind direction. The flow-field in front of a wind turbine array changes with wind direction and hence...... the individual power output of each turbine. By incorporating the current IEC standards on power performance measurements, the bias in the power performance of turbines in an array over an isolated rotor is determined. The power change depends on the position of the turbine in the array and reaches maximally 9...

  18. Design of Large Wind Turbines using Fluid-Structure Coupling Technique

    DEFF Research Database (Denmark)

    Sessarego, Matias

    Aerodynamic and structural dynamic performance analysis of modern wind turbines are routinely carried out in the wind energy field using computational tools known as aero-elastic codes. Most aero-elastic codes use the blade element momentum (BEM) technique to model the rotor aerodynamics and a mo......Aerodynamic and structural dynamic performance analysis of modern wind turbines are routinely carried out in the wind energy field using computational tools known as aero-elastic codes. Most aero-elastic codes use the blade element momentum (BEM) technique to model the rotor aerodynamics...... and a modal, multi-body, or finite-element approach to model the turbine structural dynamics. A novel aeroelastic code has been developed called MIRAS-FLEX. MIRAS-FLEX is an improvement on standard aero-elastic codes because it uses a more advanced aerodynamic model than BEM. MIRAS-FLEX combines the three......-dimensional viscous-inviscid interactive method, MIRAS, with the dynamics model used in the aero-elastic code FLEX5. Following the development of MIRAS-FLEX, a surrogate optimization methodology using MIRAS alone has been developed for the aerodynamic design of wind-turbine rotors. Designing a rotor using...

  19. Aero-elastic stability of airfoil flow using 2-D CFD

    Energy Technology Data Exchange (ETDEWEB)

    Johansen, J. [Risoe National Lab., Roskilde (Denmark)

    1999-03-01

    A three degrees-of-freedom structural dynamics model has been coupled to a two-dimensional incompressible CFD code. The numerical investigation considers aero-elastic stability for two different airfoils; the NACA0012 and the LM 2 18 % airfoils. Stable and unstable configurations and limit cycle oscillations are predicted in accordance with literature for the first airfoil. An attempt to predict stall induced edge-wise vibrations on a wind turbine airfoil fails using this two-dimensional approach. (au)

  20. Demonstration of partial pitch 2-bladed wind turbine

    DEFF Research Database (Denmark)

    Kim, Taeseong; Zahle, Frederik; Troldborg, Niels

    This is the final report for the EUDP project performed from January 2012 to December 2015. The main objective for the project was to demonstrate the potential of the partial pitch two-bladed (PP-2B) technology. DTU Wind Energy took a responsibility for three workpackages (WPs) among 6 WPs which...... were aerodynamic evaluation of partial pitch technology (WP2), aeroelastic analysis of two-bladed turbine (WP3) and On-site testing (WP4). For the WP2, a comprehensive set of 3D CFD simulations including the gap between inner and outer part of the blade and vortex generators (VGs) of both cross...... pitch concept and detailed load analyses were performed. Also the comparison studies between numerical results and experimental results were performed. Moreover stability analyses for the PP- 2B turbine have been performed with HAWC2 and modal analysis using Hill’s method was performed to calculate...

  1. A modern course in aeroelasticity

    CERN Document Server

    Dowell, Earl H

    2015-01-01

    This book cover the basics of aeroelasticity or the dynamics of fluid-structure interaction. While the field began in response to the rapid development of aviation, it has now expanded into many branches of engineering and scientific disciplines and treat physical phenomena from aerospace engineering, bioengineering, civil engineering, and mechanical engineering in addition to drawing the attention of mathematicians and physicists.   The basic questions addressed are dynamic stability and response of fluid structural systems as revealed  by both linear and nonlinear mathematical models and correlation with experiment. The use of scaled models and full scale experiments and tests play a key role where theory is not considered sufficiently reliable.  In this new edition the more recent literature on nonlinear aeroelasticity has been brought up to date and the opportunity has been taken to correct the inevitable typographical errors that the authors and our readers have found to date. The early chapters of t...

  2. A numerical study on the flow upstream of a wind turbine on complex terran

    DEFF Research Database (Denmark)

    Meyer Forsting, Alexander Raul; Bechmann, Andreas; Troldborg, Niels

    2016-01-01

    The interaction of a wind turbine with the upstream flow-field in complex and flat terrain is studied using Reynolds-averaged Navier-Stokes (RANS) simulations with a two equation turbulence closure. The complex site modelled is Perdigao (Portugal), where a turbine is located on one of two parallel...... the wind turbine wake trajectory which in turn governs the orientation of the induction zone...

  3. Aeroelastic simulation of higher harmonic control

    Science.gov (United States)

    Robinson, Lawson H.; Friedmann, Peretz P.

    1994-01-01

    This report describes the development of an aeroelastic analysis of a helicopter rotor and its application to the simulation of helicopter vibration reduction through higher harmonic control (HHC). An improved finite-state, time-domain model of unsteady aerodynamics is developed to capture high frequency aerodynamic effects. An improved trim procedure is implemented which accounts for flap, lead-lag, and torsional deformations of the blade. The effect of unsteady aerodynamics is studied and it is found that its impact on blade aeroelastic stability and low frequency response is small, but it has a significant influence on rotor hub vibrations. Several different HHC algorithms are implemented on a hingeless rotor and their effectiveness in reducing hub vibratory shears is compared. All the controllers are found to be quite effective, but very differing HHC inputs are required depending on the aerodynamic model used. Effects of HHC on rotor stability and power requirements are found to be quite small. Simulations of roughly equivalent articulated and hingeless rotors are carried out, and it is found that hingeless rotors can require considerably larger HHC inputs to reduce vibratory shears. This implies that the practical implementation of HHC on hingeless rotors might be considerably more difficult than on articulated rotors.

  4. Aeroelastic Modeling of a Nozzle Startup Transient

    Science.gov (United States)

    Wang, Ten-See; Zhao, Xiang; Zhang, Sijun; Chen, Yen-Sen

    2014-01-01

    Lateral nozzle forces are known to cause severe structural damage to any new rocket engine in development during test. While three-dimensional, transient, turbulent, chemically reacting computational fluid dynamics methodology has been demonstrated to capture major side load physics with rigid nozzles, hot-fire tests often show nozzle structure deformation during major side load events, leading to structural damages if structural strengthening measures were not taken. The modeling picture is incomplete without the capability to address the two-way responses between the structure and fluid. The objective of this study is to develop a tightly coupled aeroelastic modeling algorithm by implementing the necessary structural dynamics component into an anchored computational fluid dynamics methodology. The computational fluid dynamics component is based on an unstructured-grid, pressure-based computational fluid dynamics formulation, while the computational structural dynamics component is developed under the framework of modal analysis. Transient aeroelastic nozzle startup analyses at sea level were performed, and the computed transient nozzle fluid-structure interaction physics presented,

  5. Operation window and part-load performance study of a syngas fired gas turbine

    International Nuclear Information System (INIS)

    He, Fen; Li, Zheng; Liu, Pei; Ma, Linwei; Pistikopoulos, Efstratios N.

    2012-01-01

    Integrated coal gasification combined cycle (IGCC) provides a great opportunity for clean utilization of coal while maintaining the advantage of high energy efficiency brought by gas turbines. A challenging problem arising from the integration of an existing gas turbine to an IGCC system is the performance change of the gas turbine due to the shift of fuel from natural gas to synthesis gas, or syngas, mainly consisting of carbon monoxide and hydrogen. Besides the change of base-load performance, which has been extensively studied, the change of part-load performance is also of great significance for the operation of a gas turbine and an IGCC plant. In this paper, a detailed mathematical model of a syngas fired gas turbine is developed to study its part-load performance. A baseline is firstly established using the part-load performance of a natural gas fired gas turbine, then the part-load performance of the gas turbine running with different compositions of syngas is investigated and compared with the baseline. Particularly, the impacts of the variable inlet guide vane, the degree of fuel dilution, and the degree of air bleed are investigated. Results indicate that insufficient cooling of turbine blades and a reduced compressor surge margin are the major factors that constrain the part-load performance of a syngas fired gas turbine. Results also show that air bleed from the compressor can greatly improve the working condition of a syngas fired gas turbine, especially for those fired with low lower heating value syngas. The regulating strategy of a syngas fired gas turbine should also be adjusted in accordance to the changes of part-load performance, and a reduced scope of constant TAT (turbine exhaust temperature) control mode is required.

  6. Propagation of low-level jet's signals across the wind turbine structures

    Science.gov (United States)

    Gutierrez, Walter; Ruiz-Columbie, Arquimedes; Tutkun, Murat; Castillo, Luciano

    2017-11-01

    Low-level jets (LLJs) are identified as relative maxima in the vertical profile of the horizontal wind speed at the top of the stable boundary layer. Such peaks constitute major power resources, since they are observed at altitudes within the heights of commercial-size wind turbines (e.g., 40m and 100 m). However, the stronger wind speed and the stronger wind shear below the peak altitude can also increase the mechanical loading on the wind turbine. Moreover, LLJs can act as a carrier of firm frequencies that can excite several of the turbine's parts. How those loads and frequencies are replicated along the turbine's structure has not been thoroughly studied. Using high-frequency data of actual atmospheric LLJ as input for the NREL aeroelastic simulator FAST, together with spectral analysis, we determine how the signal from the incoming wind is first created at the elements facing the wind and then transported across all turbine's parts. We found that the tower is the main source of perturbation breaking the symmetry of many of the turbine's responses. Results from this research can provide a better understanding of how several LLJ's features act to exacerbate or mitigate the damages on turbine's parts. NSF-CBET #1157246, NSF-CMMI #1100948, and NSF-OISE-1243482.

  7. Study of wind turbine foundations in cold climates

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2012-11-01

    This report provides an overview of the processes at work in soil in cold climates and their effect on wind turbine foundations. Havsnaes wind farm consists of 48 turbines located in Jaemtland county in central Sweden. Havsnaes has provided an appropriate research environment to investigate the engineering challenges related to the design and construction of wind turbine foundations in sub-arctic conditions and the experienced gained from this project informs this report.

  8. Experimental study to the influences of rotational speed and blade shape on water vortex turbine performance

    Science.gov (United States)

    Kueh, T. C.; Beh, S. L.; Ooi, Y. S.; Rilling, D. G.

    2017-04-01

    Water vortex turbine utilizes the natural behaviour of water to form free surface vortex for energy extraction. This allows simple construction and ease of management on the whole water vortex power plant system. To our findings, the literature study specifically on water vortex turbine is inadequate and low efficiency was reported. Influences of operating speed and blade shape on turbine performance are the two parameters investigated in this study. Euler Turbomachinery Equation and velocity triangle are used in the improvement analysis. Two turbines with flat blades and curved blades are tested and compared. Both turbines show similar rotational speed at no load condition. This suggested that the circulation force of the water vortex has more dominant effect on the turbine rotational speed, compared to the turbine’s geometry. Flat-blades turbine showed maximum efficiency of 21.63% at 3.27 rad/s whereas curved-blades turbine showed 22.24% at 3.56 rad/s. When operating load is applied, the backward-leaning curve helps the turbine blades to reduce the disturbance on the water vortex, and hence provide a better performance.

  9. Studi Eksperimen Perbandingan Pengaruh Variasi Tekanan Inlet Turbin danVariasi Pembebanan Terhadap Karakteristik Turbin Pada Organic Rankine Cycle

    Directory of Open Access Journals (Sweden)

    Dwi Dharma Risqiawan

    2013-12-01

    Full Text Available Sistem pembangkit listrik telah berinovasi pada saat ini untuk tetap memenuhi kebutuhan akan ketersediaan listrik salah satunya dengan Organic Rankine Cycle (ORC. Sistem ini terdiri dari empat komponen utama yaitu evaporator, turbin, kondensor, dan pompa.Fluida kerja dipompa ke evaporator untuk membangkitkan uap lalu digunakan menggerakkan turbin.Uap hasil ekspansi turbin dikondensasi dan dialirkan oleh pompa kembali ke evaporator.Sistem ini mampu memanfaatkan sumber energi yang memiliki temperatur dan tekanan rendah untuk membangkitkan uap fluida organik. Penelitian ini dilakukan untuk mengevaluasi kinerja turbin pada sistem ORC dengan memvariasikan tekanan masuk turbin dan pembebanan dengan menggunakan R-123 sebagai fluida kerja .Pengambilan data dilakukan dengan memvariasikan tekanan masuk turbin pada setiap variasi pembebanan generator.Pengamatan dilakukan hanya pada turbin untuk mengetahui karakteristik turbin yang digunakan saat ini.Pengambilan data dilakukan dengan R-123 sebagai fluida kerja. Dari eksperimen didapatkan temperatur masuk dan keluar turbin,kecepatan putaran turbin dalam rpm, dan enthalpy dapat diketahui. Enthalpy digunakan untuk mengitung kerja yang dihasilkan turbin, efisiensi turbin dan efisiensi sudu turbin.Pada tekanan masuk turbin 8 bar dan beban 1000 Watt data dengan nilai terbaik didapatkan.Hasil perhitungan data didapatkan kerja yang dihasilkan turbin yang terbesar adalah 5,4 KW. Hasil lain yang dapat diketahui adalah efisiensi turbin tertinggi 88%. Efisiensi sudu turbin tertinggi yang terhitung adalah 42,9%.

  10. Physical and Numerical Model Studies of Cross-flow Turbines Towards Accurate Parameterization in Array Simulations

    Science.gov (United States)

    Wosnik, M.; Bachant, P.

    2014-12-01

    Cross-flow turbines, often referred to as vertical-axis turbines, show potential for success in marine hydrokinetic (MHK) and wind energy applications, ranging from small- to utility-scale installations in tidal/ocean currents and offshore wind. As turbine designs mature, the research focus is shifting from individual devices to the optimization of turbine arrays. It would be expensive and time-consuming to conduct physical model studies of large arrays at large model scales (to achieve sufficiently high Reynolds numbers), and hence numerical techniques are generally better suited to explore the array design parameter space. However, since the computing power available today is not sufficient to conduct simulations of the flow in and around large arrays of turbines with fully resolved turbine geometries (e.g., grid resolution into the viscous sublayer on turbine blades), the turbines' interaction with the energy resource (water current or wind) needs to be parameterized, or modeled. Models used today--a common model is the actuator disk concept--are not able to predict the unique wake structure generated by cross-flow turbines. This wake structure has been shown to create "constructive" interference in some cases, improving turbine performance in array configurations, in contrast with axial-flow, or horizontal axis devices. Towards a more accurate parameterization of cross-flow turbines, an extensive experimental study was carried out using a high-resolution turbine test bed with wake measurement capability in a large cross-section tow tank. The experimental results were then "interpolated" using high-fidelity Navier--Stokes simulations, to gain insight into the turbine's near-wake. The study was designed to achieve sufficiently high Reynolds numbers for the results to be Reynolds number independent with respect to turbine performance and wake statistics, such that they can be reliably extrapolated to full scale and used for model validation. The end product of

  11. Research in aeroelasticity EFP-2002; Forskning i aeroelasticitet EFP-2002

    Energy Technology Data Exchange (ETDEWEB)

    Bak, Christian (ed.)

    2004-02-01

    This report contains results from the Energy Research Project 'Application, demonstration and further development of advanced aerodynamic and aeroelastic models' (EFP 2002), covering the time from July 1 2002 to December 31 2003. The partners in the project are Risoe National Labo-ratory (Risoe), The Technical University of Denmark (DTU), Bonus Energy A/S, LM Glasfiber A/S, NEG Micon A/S og Vestas Wind Systems A/S. In the project, Risoe and DTU have de-monstrated the application of their advanced computational methods on several different mega-Watt-size wind turbine designs. Compared to traditional methods the advanced methods have among other results shown: 1) that the aerodynamics at the blade tip for a wind turbine cannot be analysed correctly for a non-rotating blade. 2) that the drag coefficient distribution on a rotor in stand still according to Computational Fluid Dynamics should be increased from the blade root towards the blade tip. 3) that the maximum 2D lift coefficient in airfoil characteristics should be reduced at the blade tip and should be increased significantly on the inner part of the rotor. The drag coefficients should in general be increased for all sections on the blade, when the flow is separating. 4) that the choice of airfoil characteristics, aerodynamical as well as structural, are impor-tant for the loads, the noise and the design of a wind turbine. 5) that blade edgewise vibrations in stand still computed with an aeroelastic code are most critical around 40 deg. and 140 deg. angles of attack and that these vibrations depend completely on the given values of lift and drag. 6) that the energy production decreases in the case of large deflections of the blades. 7) that the blade flap eigenfrequency increases in the case of large deflections. 8) that there is an increased coupling between blade edge and blade torsional frequency in the case of large deflections. 9) that an overview of the dynamics for a wind turbine design can be

  12. Cross-flow turbines: physical and numerical model studies towards improved array simulations

    Science.gov (United States)

    Wosnik, M.; Bachant, P.

    2015-12-01

    Cross-flow, or vertical-axis turbines, show potential in marine hydrokinetic (MHK) and wind energy applications. As turbine designs mature, the research focus is shifting from individual devices towards improving turbine array layouts for maximizing overall power output, i.e., minimizing wake interference for axial-flow turbines, or taking advantage of constructive wake interaction for cross-flow turbines. Numerical simulations are generally better suited to explore the turbine array design parameter space, as physical model studies of large arrays at large model scale would be expensive. However, since the computing power available today is not sufficient to conduct simulations of the flow in and around large arrays of turbines with fully resolved turbine geometries, the turbines' interaction with the energy resource needs to be parameterized, or modeled. Most models in use today, e.g. actuator disk, are not able to predict the unique wake structure generated by cross-flow turbines. Experiments were carried out using a high-resolution turbine test bed in a large cross-section tow tank, designed to achieve sufficiently high Reynolds numbers for the results to be Reynolds number independent with respect to turbine performance and wake statistics, such that they can be reliably extrapolated to full scale and used for model validation. To improve parameterization in array simulations, an actuator line model (ALM) was developed to provide a computationally feasible method for simulating full turbine arrays inside Navier--Stokes models. The ALM predicts turbine loading with the blade element method combined with sub-models for dynamic stall and flow curvature. The open-source software is written as an extension library for the OpenFOAM CFD package, which allows the ALM body force to be applied to their standard RANS and LES solvers. Turbine forcing is also applied to volume of fluid (VOF) models, e.g., for predicting free surface effects on submerged MHK devices. An

  13. Study of transient turbine shot without bypass in a BWR

    International Nuclear Information System (INIS)

    Vallejo Q, J. A.; Martin del Campo M, C.; Fuentes M, L.; Francois L, J. L.

    2015-09-01

    The study and analysis of operational transients are important for predicting the behavior of a system to short-terms events and the impact that would cause this transition. For the nuclear industry these studies are indispensable due to economic, environmental and social impacts that could result in an accident during the operation of a nuclear reactor. In this paper the preparation, simulation and analysis of results of a turbine shot transient, which is not taken into operation the bypass is presented. The study is realized for a BWR of 2027 MWt, to an intermediate cycle life and using the computer code Simulate-3K a depressurization stage of the vessel is created which shows the response of other security systems and gives a coherent prediction to the event presented type. (Author)

  14. Aeroelasticity Benchmark Assessment: Subsonic Fixed Wing Program

    Science.gov (United States)

    Florance, Jennifer P.; Chwalowski, Pawel; Wieseman, Carol D.

    2010-01-01

    The fundamental technical challenge in computational aeroelasticity is the accurate prediction of unsteady aerodynamic phenomena and the effect on the aeroelastic response of a vehicle. Currently, a benchmarking standard for use in validating the accuracy of computational aeroelasticity codes does not exist. Many aeroelastic data sets have been obtained in wind-tunnel and flight testing throughout the world; however, none have been globally presented or accepted as an ideal data set. There are numerous reasons for this. One reason is that often, such aeroelastic data sets focus on the aeroelastic phenomena alone (flutter, for example) and do not contain associated information such as unsteady pressures and time-correlated structural dynamic deflections. Other available data sets focus solely on the unsteady pressures and do not address the aeroelastic phenomena. Other discrepancies can include omission of relevant data, such as flutter frequency and / or the acquisition of only qualitative deflection data. In addition to these content deficiencies, all of the available data sets present both experimental and computational technical challenges. Experimental issues include facility influences, nonlinearities beyond those being modeled, and data processing. From the computational perspective, technical challenges include modeling geometric complexities, coupling between the flow and the structure, grid issues, and boundary conditions. The Aeroelasticity Benchmark Assessment task seeks to examine the existing potential experimental data sets and ultimately choose the one that is viewed as the most suitable for computational benchmarking. An initial computational evaluation of that configuration will then be performed using the Langley-developed computational fluid dynamics (CFD) software FUN3D1 as part of its code validation process. In addition to the benchmarking activity, this task also includes an examination of future research directions. Researchers within the

  15. Preliminary study of Low-Cost Micro Gas Turbine

    Science.gov (United States)

    Fikri, M.; Ridzuan, M.; Salleh, Hamidon

    2016-11-01

    The electricity consumption nowadays has increased due to the increasing development of portable electronic devices. The development of low cost micro gas turbine engine, which is designed for the purposes of new electrical generation Micro turbines are a relatively new distributed generation technology being used for stationary energy generation applications. They are a type of combustion turbine that produces both heat and electricity on a relatively small scaled.. This research are focusing of developing a low-cost micro gas turbine engine based on automotive turbocharger and to evaluation the performance of the developed micro gas turbine. The test rig engine basically was constructed using a Nissan 45V3 automotive turbocharger, containing compressor and turbine assemblies on a common shaft. The operating performance of developed micro gas turbine was analyzed experimentally with the increment of 5000 RPM on the compressor speed. The speed of the compressor was limited at 70000 RPM and only 1000 degree Celsius at maximum were allowed to operate the system in order to avoid any failure on the turbocharger bearing and the other components. Performance parameters such as inlet temperature, compressor temperature, exhaust gas temperature, and fuel and air flow rates were measured. The data was collected electronically by 74972A data acquisition and evaluated manually by calculation. From the independent test shows the result of the system, The speed of the LP turbine can be reached up to 35000 RPM and produced 18.5kw of mechanical power.

  16. Wind Turbine Acoustic Investigation: Infrasound and Low-Frequency Noise--A Case Study

    Science.gov (United States)

    Ambrose, Stephen E.; Rand, Robert W.; Krogh, Carmen M. E.

    2012-01-01

    Wind turbines produce sound that is capable of disturbing local residents and is reported to cause annoyance, sleep disturbance, and other health-related impacts. An acoustical study was conducted to investigate the presence of infrasonic and low-frequency noise emissions from wind turbines located in Falmouth, Massachusetts, USA. During the…

  17. Study and program plan for improved heavy duty gas turbine engine ceramic component development

    Science.gov (United States)

    Helms, H. E.

    1977-01-01

    Fuel economy in a commercially viable gas turbine engine was demonstrated through use of ceramic materials. Study results show that increased turbine inlet and generator inlet temperatures, through the use of ceramic materials, contribute the greatest amount to achieving fuel economy goals. Improved component efficiencies show significant additional gains in fuel economy.

  18. Study on optimal design of wind turbine blade airfoil and its application

    International Nuclear Information System (INIS)

    Sun, Min Young; Kim, Dong Yong; Lim, Jae Kyoo

    2012-01-01

    This study was carried out with two goals. One was the development of a model of a wind turbine blade airfoil and the other was the application of the folding blade. In general, in large sized (MW) wind turbines, damage is prevented in small wind turbines since equipment costs and maintenance costs are high, and therefore, the blade will cause serious damage. The wind turbine proposed in this study does not require maintenance, and the blades do not break during high winds because they are folded in accordance with changes in the wind speed. But generators are not cut out, while maintaining a constant angle will continue to produce. The focus of this study, the wind turbine is continued by folding blade system in strong winds and gusts without stopping production

  19. Transient Thunderstorm Downbursts and Their Effects on Wind Turbines

    Directory of Open Access Journals (Sweden)

    Hieu H. Nguyen

    2014-10-01

    Full Text Available The International Electrotechnical Commission (IEC Standard 61400-1 for the design of wind turbines does not explicitly address site-specific conditions associated with anomalous atmospheric events or conditions. Examples of off-standard atmospheric conditions include thunderstorm downbursts, hurricanes, tornadoes, low-level jets, etc. The simulation of thunderstorm downbursts and associated loads on a utility-scale wind turbine is the focus of this study. Since the problem has not received sufficient attention, especially in terms of design, we thus focus in this paper on practical aspects. A wind field model that incorporates component non-turbulent and turbulent parts is described and employed in inflow simulations. The non-turbulent part is based on an available analytical model with some modifications, while the turbulent part is simulated as a stochastic process using standard turbulence power spectral density functions and coherence functions whose defining parameters are related to the downburst characteristics such as the storm translation velocity. Available information on recorded downbursts is used to define two storm scenarios that are studied. Rotor loads are generated using stochastic simulation of the aeroelastic response of a model of a utility-scale 5-MW turbine. An illustrative single storm simulation and the associated turbine response are used to discuss load characteristics and to highlight storm-related and environmental parameters of interest. Extensive simulations for two downbursts are then conducted while varying the storm’s location and track relative to the turbine. Results suggest that wind turbine yaw and pitch control systems clearly influence overall system response. Results also highlight the important effects of both the turbulence as well as the downburst mean wind profiles on turbine extreme loads.

  20. Environmental Effects of Hydrokinetic Turbines on Fish: Desktop and Laboratory Flume Studies

    Energy Technology Data Exchange (ETDEWEB)

    Jacobson, Paul T. [Electric Power Research Institute; Amaral, Stephen V. [Alden Research Laboratory; Castro-Santos, Theodore [U.S. Geological Survey; Giza, Dan [Alden Research Laboratory; Haro, Alexander J. [U.S. Geological Survey; Hecker, George [Alden Research Laboratory; McMahon, Brian [Alden Research Laboratory; Perkins, Norman [Alden Research Laboratory; Pioppi, Nick [Alden Research Laboratory

    2012-12-31

    This collection of three reports describes desktop and laboratory flume studies that provide information to support assessment of the potential for injury and mortality of fish that encounter hydrokinetic turbines of various designs installed in tidal and river environments. Behavioral responses to turbine exposure also are investigated to support assessment of the potential for disruptions to upstream and downstream movements of fish. The studies: (1) conducted an assessment of potential injury mechanisms using available data from studies with conventional hydro turbines; (2) developed theoretical models for predicting blade strike probabilities and mortality rates; and (3) performed flume testing with three turbine designs and several fish species and size groups in two laboratory flumes to estimate survival rates and document fish behavior. The project yielded three reports which this document comprises. The three constituent documents are addressed individually below Fish Passage Through Turbines: Application of Conventional Hydropower Data to Hydrokinetic Technologies Fish passing through the blade sweep of a hydrokinetic turbine experience a much less harsh physical environment than do fish entrained through conventional hydro turbines. The design and operation of conventional turbines results in high flow velocities, abrupt changes in flow direction, relatively high runner rotational and blade speeds, rapid and significant changes in pressure, and the need for various structures throughout the turbine passageway that can be impacted by fish. These conditions generally do not occur or are not significant factors for hydrokinetic turbines. Furthermore, compared to conventional hydro turbines, hydrokinetic turbines typically produce relatively minor changes in shear, turbulence, and pressure levels from ambient conditions in the surrounding environment. Injuries and mortality from mechanical injuries will be less as well, mainly due to low rotational speeds and

  1. Research in aeroelasticity EFP-2006

    DEFF Research Database (Denmark)

    This report contains the results from the Energy Research Project ”Program for Research in Applied Aeroelasticity, EFP-2006” covering the period from 1. April 2006 to 31. March 2007. A summary of the main results from the project is given in the following. The aerodynamics for rotors incl. spinner...... that they can be used successfully, but that downwind and short winglets are most efficient. Investigating a strategy for reduction of loads and vibrations at extreme wind speeds showed that there are considerably uncertainties in the numerical models and that the main concluding remark is that measurements...

  2. Analysis and Tests of Pultruded Blades for Wind Turbine Rotors

    Energy Technology Data Exchange (ETDEWEB)

    Cheney, M. C.(PS Enterprises, Glastonbury, Connecticut); Olsen, T.; Quandt, G.; Archidiacono, P.

    1999-07-19

    PS Enterprises, Inc. investigated a flexible, downwind, free-yaw, five-blade rotor system employing pultruded blades. A rotor was designed, manufactured and tested in the field. A preliminary design study and proof of concept test were conducted to assess the feasibility of using pultruded blades for wind turbine rotors. A 400 kW turbine was selected for the design study and a scaled 80 kW rotor was fabricated and field tested as a demonstration of the concept. The design studies continued to support the premise that pultruded blades offer the potential for significant reductions in rotor weight and cost. The field test provided experimental performance and loads data that compared well with predictions using the FLEXDYNE aeroelastic analysis. The field test also demonstrated stable yaw behavior and the absence of stall flutter over the wind conditions tested. During the final year of the contract, several studies were conducted by a number of independent consultants to address specific technical issues related to pultruded blades that could impact the commercial viability of turbines using this technology. The issues included performance, tower strikes, yaw stability, stall flutter, fatigue, and costs. While the performance of straight pultruded blades was projected to suffer a penalty of about 13% over fully twisted and tapered blades, the study showed that an aerodynamic fairing over the inner 40% could recover 85% of that loss while still keeping the blade cost well below that of conventional blades. Other results of the study showed that with proper design, rotors using pultruded blades could operate without aeroelastic problems, have acceptable fatigue life, and cost less than half that of rotors employing conventionally manufactured blades.

  3. Structural optimization study of composite wind turbine blade

    DEFF Research Database (Denmark)

    Chen, Jin; Shen, Wen Zhong; Wang, Quan

    2013-01-01

    In this paper the initial layout of a 2. MW composite wind turbine blade is designed first. The new airfoils families are selected to design a 2. MW wind turbine blade. The finite element parametric model for the blade is established. Based on the modified Blade Element Momentum theory, a new one......-way fluid-structure interaction method is introduced. A procedure combining finite element analysis and particle swarm algorithm to optimize composite structures of the wind turbine blade is developed. The procedure proposed not only allows thickness variation but also permits the spar cap location...

  4. Study of advanced radial outflow turbine for solar steam Rankine engines

    Science.gov (United States)

    Martin, C.; Kolenc, T.

    1979-01-01

    The performance characteristics of various steam Rankine engine configurations for solar electric power generation were investigated. A radial outflow steam turbine was investigated to determine: (1) a method for predicting performance from experimental data; (2) the flexibility of a single design with regard to power output and pressure ratio; and (3) the effect of varying the number of turbine stages. All turbine designs were restricted to be compatible with commercially available gearboxes and generators. A study of several operating methods and control schemes for the steam Rankine engine shows that from an efficiency and control simplicity standpoint, the best approach is to hold turbine inlet temperature constant, vary turbine inlet pressure to match load, and allow condenser temperature to float maintaining constant heat rejection load.

  5. Aeroelastic tailoring of composite aircraft wings

    Science.gov (United States)

    Mihaila-Andres, Mihai; Larco, Ciprian; Rosu, Paul-Virgil; Rotaru, Constantin

    2017-07-01

    The need of a continuously increasing size and performance of aerospace structures has settled the composite materials as the preferred materials in aircraft structures. Apart from the clear capacity to reduce the structural weight and with it the manufacture cost and the fuel consumption while preserving proper airworthiness, the prospect of tailoring a structure using the unique directional stiffness properties of composite materials allows an aerospace engineer to optimize aircraft structures to achieve particular design objectives. This paper presents a brief review of what is known as the aeroelastic tailoring of airframes with the intent of understanding the evolution of this research topic and at the same time providing useful references for further studies.

  6. Comparative Study of Barotrauma Risk during Fish Passage through Kaplan Turbines

    Energy Technology Data Exchange (ETDEWEB)

    Richmond, Marshall C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Hydrology Group; Romero-Gomez, Pedro [Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Hydrology Group; Serkowski, John A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Hydrology Group; Rakowski, Cynthia L. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Hydrology Group; Graf, Michael J. [Voith Hydro, York, PA (United States)

    2015-10-01

    Rapid pressure changes in hydroelectric turbine flows can cause barotrauma that can be hazardous to the passage of fish, in particular migratory juvenile salmonids. Although numerous laboratory tests have evaluated the effect of rapid decompression in fish species of relevance, numerical modeling studies offer the advantage of predicting, for new turbine designs, the potential risks of mortality and injury from rapid pressure change during turbine passage. However, rapid pressure change is only one of several hydraulic risks encountered by fish during turbine passage in addition to blade strike, shear, and turbulence. To better understand the role of rapid pressure changes, the present work focuses on the application of a computational fluid dynamics based method for evaluating the risk of pressure-related mortality to fish passing through an early 1960s era original hydroelectric Kaplan turbine at Wanapum Dam (Columbia River, Washington), and a modern advanced Kaplan turbine installed in 2005. The results show that the modeling approach acceptably reproduced the nadir pressure distributions compared to field data previously collected at the site using an autonomous sensor. Our findings show that the new advanced-design unit performs better, in terms of reduced barotrauma risk to fish from exposure to low pressures, than the original turbine unit. The outcomes allow for comparative analyses of turbine designs and operations prior to installation, an advantage that can potentially be integrated in the process of designing new turbine units to achieve superior environmental performance. Overall, the results show that modern turbine designs can achieve the multiple objectives of increasing power generation, lowering cavitation potential, and reducing barotrauma risks to passing fish.

  7. Comparison of computer codes for calculating dynamic loads in wind turbines

    Science.gov (United States)

    Spera, D. A.

    1978-01-01

    The development of computer codes for calculating dynamic loads in horizontal axis wind turbines was examined, and a brief overview of each code was given. The performance of individual codes was compared against two sets of test data measured on a 100 KW Mod-0 wind turbine. All codes are aeroelastic and include loads which are gravitational, inertial and aerodynamic in origin.

  8. Electrical components library for HAWC2; Wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    Cutululis, N.A.; Larsen, Torben J.; Soerensen, Poul; Hansen, Anca D. (Risoe National Lab., DTU, Wind Energy Dept., Roskilde (DK)); Iov, F. (Aalborg Univ., Institute of Energy Technology (DK))

    2007-12-15

    The work presented in this report is part of the EFP project called ''A Simulation Platform to Model, Optimize and Design Wind Turbines'' partly funded by the Danish Energy Authority under contract number 1363/04-0008. The project is carried out in cooperation between Risoe National Laboratory and Aalborg University. In this project, the focus is on the development of a simulation platform for wind turbine systems using different simulation tools. This report presents the electric component library developed for use in the aeroelastic code HAWC2. The developed library includes both steady state and dynamical models for fixed and variable speed wind turbines. A simple steady-state slip model was developed for the fixed speed wind turbine. This model is suitable for aeroelastic design of wind turbines under normal operation. A dynamic model of an induction generator for the fixed speed wind turbine was developed. The model includes the dynamics of the rotor fluxes. The model is suitable for a more detailed investigation of the mechanical-electrical interaction, both under normal and fault operation. For the variable speed wind turbine, a steadystate model, typically used in aeroelastic design, was implemented. The model can be used for normal and, to some extent, for fault operation. The reduced order dynamic model of a DFIG was implemented. The model includes only the active power controller and can be used for normal operation conditions. (au)

  9. Multifidelity Robust Aeroelastic Design, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Nielsen Engineering & Research (NEAR) proposes a new method to generate mathematical models of wind-tunnel models and flight vehicles for robust aeroelastic...

  10. Adjustable Fidelity Computational Aeroelasticity Procedure (AFCAP) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — NextGen proposes an approach to significantly enhance aeroelastic analysis capabilities over what is commonly available in linear analysis environments such as...

  11. Presentations from the Aeroelastic Workshop - latest results from AeroOpt

    Energy Technology Data Exchange (ETDEWEB)

    Hartvig Hansen, M. (ed.)

    2011-10-15

    This report contains the slides of the presentations at the Aeroelastic Workshop held at Risoe-DTU for the wind energy industry in Denmark on October 27, 2011. The scientific part of the agenda at this workshop was 1) Detailed and reduced models of dynamic mooring system (Anders M. Hansen). 2) Bend-twist coupling investigation in HAWC2 (Taeseong Kim). 3) Q3UIC - A new aerodynamic airfoil tool including rotational effects (Nestor R. Garcia). 4) Influence of up-scaling on loads, control and aerodynamic modeling (Helge Aa. Madsen). 5) Aerodynamic damping of lateral tower vibrations (Bjarne S. Kallesoee). 6) Open- and closed-loop aeroservoelastic analysis with HAWCStab2 (Morten H. Hansen). 7) Design and test of a thick, flatback, high-lift multielement airfoil (Frederik Zahle). The presented results are mainly obtained in the EUDP project ''Aeroelastic Optimization of MW Wind Turbines (AeroOpt)''. (Author)

  12. Effect of atmospheric turbulence on wind turbine wakes: An LES study

    Science.gov (United States)

    Wu, Y. T.; Porté-Agel, F.

    2012-04-01

    A comprehensive numerical study of atmospheric turbulence effect on wind-turbine wakes is presented. Large-eddy simulations of neutrally-stratified boundary layers developed over different flat surfaces (forest, farmland, grass, and snow) are performed to investigate the structure of turbine wakes in cases where the incident flows to the wind turbine have the same mean velocity at the hub height but different mean wind shears and turbulence intensity levels. The simulation results show that the different wind shears and turbulence intensity levels of the incoming flow lead to considerable influence on the spatial distribution of the mean velocity deficit, turbulence intensity, and turbulent shear stress in the wake region downstream of the turbine. In general, the recovery of the turbine-induced wake (velocity deficit) is faster and the turbulence intensity level is higher and has its maximum closer to the turbine for wakes of turbines over rougher terrain. In order to isolate the effect of turbulence intensity from that of wind shear, simulations have also been performed with synthetic inflow velocity fields that have the same mean wind shear but different turbulence intensity levels. We find that the effect of the inflow turbulence intensity on the wake recovery and turbulence levels is stronger than that of the mean shear.

  13. Numerical study on Wells turbine with penetrating blade tip treatments for wave energy conversion

    Directory of Open Access Journals (Sweden)

    Ying Cui

    2016-09-01

    Full Text Available In order to optimize the performance of a Wells turbine with fixed guide vanes, the designs of an end plate and a ring on the tip of the turbine rotor are proposed as penetrating blade tip treatments. In this study, numerical investigations are made using computational fluid dynamics (CFD-based ANSYS Fluent software, and validated by corresponding experimental data. The flow fields are analyzed and non-dimensional coefficients CA, CT and η are calculated under steady-state conditions. Numerical results show that the stalling phenomenon on a ring-type Wells turbine occurs at a flow coefficient of ϕ = 0.36, and its peak efficiency can reach 0.54, which is 16% higher than that of an unmodified turbine and 9% higher than in the case of an endplate-type turbine. In addition, quasi-steady analysis is used to calculate the mean efficiency and output work of a wave cycle under sinusoidal flow conditions. As a result, it has been found that the ring-type turbine is superior to other types of Wells turbines.

  14. Comparative study on the wake deflection behind yawed wind turbine models

    Science.gov (United States)

    Schottler, Jannik; Mühle, Franz; Bartl, Jan; Peinke, Joachim; Adaramola, Muyiwa S.; Sætran, Lars; Hölling, Michael

    2017-05-01

    In this wind tunnel campaign, detailed wake measurements behind two different model wind turbines in yawed conditions were performed. The wake deflections were quantified by estimating the rotor-averaged available power within the wake. By using two different model wind turbines, the influence of the rotor design and turbine geometry on the wake deflection caused by a yaw misalignment of 30° could be judged. It was found that the wake deflections three rotor diameters downstream were equal while at six rotor diameters downstream insignificant differences were observed. The results compare well with previous experimental and numerical studies.

  15. A Numerical Study on a Vertical-Axis Wind Turbine with Inclined Arms

    OpenAIRE

    Agostino De Marco; Domenico P. Coiro; Domenico Cucco; Fabrizio Nicolosi

    2014-01-01

    This work focuses on a particular type of vertical-axis wind turbine, in which a number of inclined arms with airfoil-shaped cross-sections are mounted to connect the principal blades to their hub. While the majority of the known studies on vertical-axis turbines is devoted to the role of principal blades, in most of the cases without taking into account other parts of the wind turbine, the objective of this work is to investigate the effect of uncommon arm geometries, such as the inclined ar...

  16. Design study of 10 kW superconducting generator for wind turbine applications

    DEFF Research Database (Denmark)

    Abrahamsen, Asger Bech; Mijatovic, Nenad; Seiler, Eugen

    2009-01-01

    = 1 Tesla to be similar to the performance of permanent magnets and to represent a layout, which can be scaled up in future off-shore wind turbines. The proposed generator is a 8 pole synchronous machine based on race-track coils of high temperature superconducting tapes and an air cored copper stator......We have performed a design study of a 10 kW superconducting slow rotating generator suitable for demonstration in a small scale wind turbine, where the drive train only consists of the turbine blades connected directly to the generator. The flux density in the superconducting rotor is chosen as B...

  17. Study on Modelling Standardization of Double-fed Wind Turbine and Its Application

    Directory of Open Access Journals (Sweden)

    Li Xiang

    2016-01-01

    Full Text Available Based on the standardized modelling of the International Modelling Team, study on double-fed induction generator (DFIG wind turbine is processed in this paper, aiming at capability of universally and reasonably reflecting key performance related to large scale system analysis. The standardized model proposed is of high degree of structural modularity, easy functional extension and universalization of control strategy and signal. Moreover, it is applicable for wind turbines produced by different manufacturers through model parameter adjustment. The complexity of the model can meet both needs of grid-connected characteristic simulation of wind turbine and large scale power system simulation.

  18. EA Annex XX. Comparison between calculations and measurements on a wind turbine in the NASA-Ames wind tunnel

    Energy Technology Data Exchange (ETDEWEB)

    Schepers, J.G. [ECN Wind Energy, Petten (Netherlands)

    2007-11-15

    This report describes a study in which calculational results from ECN's aeroelastic code PHATAS and the free wake lifting line code AWSM are compared with wind tunnel measurements which were carried out by NREL on a wind turbine, placed in the large NASA-Ames wind tunnel. Measurements have been taken at a large variety of conditions but in this report data at non-yawed conditions are considered only. The study was carried out within the framework IEA Annex XX 'Analysis of NASA-Ames windtunnel measurements'.

  19. A study on thick plate forming for hollow-partitioned steam turbine nozzle

    Science.gov (United States)

    Kwak, Bong-Seok; Kang, Byeong-Kwon; Yoon, Mahn-Jung; Jeon, Jae-Young; Kang, Beom-Soo; Ku, Tae-Wan

    2017-10-01

    In thermal and nuclear power plants, steam turbine system to generate electric power is composed of turbine rotor assemblies for high-pressure (HP) and low-pressure (LP) turbines, its main shaft, and turbine nozzle diaphragms, and so forth. Especially, the turbine nozzle diaphragm consists of many turbine nozzles with three-dimensional asymmetric shape and complicated surface curvatures at each turbine stage. In this study, main goal is tool design and fabrication, and its application to thick plate cold forming for replacing solid-type turbine nozzle manufactured by a series of metal forging process with hollow-partitioned one obtained from cold forming. The hollow-partitioned turbine nozzle (stator) has asymmetric curvature contours, so it is hard to adopt a series of draw-bead or blank holder. Thus, the thick plate as a thick blank experiences unstable and non-uniform contact on the tool surfaces in the die cavity. To easy this unstable positioning restraint in the thick plate forming, the shoulder angles of the forming punch and the lower die are selected as the geometric process parameter to control the blank position in the die cavity. The thick plate material is 409L stainless steel (SUS409L) with initial thickness of 5.00mm, and the dimensions are a length of about 980.00mm and a width of roughly 372.60mm. Uni-axial tensile tests for the initial blank material of SUS409L are performed to verify the mechanical properties including the anisotropic characteristics, and finite element simulations are carried out using ABAQUS Explicit/Implicit. As the obtained and summarized results, the suitable shoulder angle combinations of the lower die and the punch were verified as (30°, 90°) and (45°, 90°), and then the transverse blank direction (TD) of SUS409L thick plate was investigated to be well matched.

  20. High temperature gas-cooled reactor: gas turbine application study

    Energy Technology Data Exchange (ETDEWEB)

    1980-12-01

    The high-temperature capability of the High-Temperature Gas-Cooled Reactor (HTGR) is a distinguishing characteristic which has long been recognized as significant both within the US and within foreign nuclear energy programs. This high-temperature capability of the HTGR concept leads to increased efficiency in conventional applications and, in addition, makes possible a number of unique applications in both electrical generation and industrial process heat. In particular, coupling the HTGR nuclear heat source to the Brayton (gas turbine) Cycle offers significant potential benefits to operating utilities. This HTGR-GT Application Study documents the effort to evaluate the appropriateness of the HTGR-GT as an HTGR Lead Project. The scope of this effort included evaluation of the HTGR-GT technology, evaluation of potential HTGR-GT markets, assessment of the economics of commercial HTGR-GT plants, and evaluation of the program and expenditures necessary to establish HTGR-GT technology through the completion of the Lead Project.

  1. Comparison of two LES codes for wind turbine wake studies

    DEFF Research Database (Denmark)

    Chivaee, Hamid Sarlak; Pierella, F.; Mikkelsen, Robert Flemming

    2014-01-01

    For the third time a blind test comparison in Norway 2013, was conducted comparing numerical simulations for the rotor Cp and Ct and wake profiles with the experimental results. As the only large eddy simulation study among participants, results of the Technical University of Denmark (DTU) using...... their in-house CFD solver, EllipSys3D, proved to be more reliable among the other models for capturing the wake profiles and the turbulence intensities downstream the turbine. It was therefore remarked in the workshop to investigate other LES codes to compare their performance with EllipSys3D. The aim...... of this paper is to investigate on two CFD solvers, the DTU's in-house code, EllipSys3D and the open-sourse toolbox, OpenFoam, for a set of actuator line based LES computations. Two types of simulations are performed: the wake behind a signle rotor and the wake behind a cluster of three inline rotors. Results...

  2. High temperature gas-cooled reactor: gas turbine application study

    International Nuclear Information System (INIS)

    1980-12-01

    The high-temperature capability of the High-Temperature Gas-Cooled Reactor (HTGR) is a distinguishing characteristic which has long been recognized as significant both within the US and within foreign nuclear energy programs. This high-temperature capability of the HTGR concept leads to increased efficiency in conventional applications and, in addition, makes possible a number of unique applications in both electrical generation and industrial process heat. In particular, coupling the HTGR nuclear heat source to the Brayton (gas turbine) Cycle offers significant potential benefits to operating utilities. This HTGR-GT Application Study documents the effort to evaluate the appropriateness of the HTGR-GT as an HTGR Lead Project. The scope of this effort included evaluation of the HTGR-GT technology, evaluation of potential HTGR-GT markets, assessment of the economics of commercial HTGR-GT plants, and evaluation of the program and expenditures necessary to establish HTGR-GT technology through the completion of the Lead Project

  3. Experimental study on the heavy-duty gas turbine combustor

    International Nuclear Information System (INIS)

    Antonovsky, V.; Ahn, Kook Young

    2000-01-01

    The results of stand and field testing of a combustion chamber for a heavy-duty 150 MW gas turbine are discussed. The model represented one of 14 identical segments of a tubular multican combustor constructed in the scale 1:1. The model experiments were executed at a pressure smaller than in the real gas turbine. The combustion efficiency, pressure loss factor, pattern factor, liner wall temperature, flame radiation, fluctuating pressure, and NOx emission were measured at partial and full load for both model and on-site testing. The comparison of these items of information, received on similar modes in the stand and field tests, has allowed the development of a method of calculation and the improvement of gas turbine combustors

  4. Study on visual detection method for wind turbine blade failure

    Science.gov (United States)

    Chen, Jianping; Shen, Zhenteng

    2018-02-01

    Start your abstract here…At present, the non-destructive testing methods of the wind turbine blades has fiber bragg grating, sound emission and vibration detection, but there are all kinds of defects, and the engineering application is difficult. In this regard, three-point slope deviation method, which is a kind of visual inspection method, is proposed for monitoring the running status of wind turbine blade based on the image processing technology. A better blade image can be got through calibration, image splicing, pretreatment and threshold segmentation algorithm. Design of the early warning system to monitor wind turbine blade running condition, recognition rate, stability and impact factors of the method were statistically analysed. The experimental results shown showed that it has highly accurate and good monitoring effect.

  5. A study for the optimal operating conditions of the gas turbine based combined cycle cogeneration power plant

    International Nuclear Information System (INIS)

    Cho, Young Bin; Sohn, Jeong Lak; Ro, Sung Tack

    2004-01-01

    The purpose of this study is to show the existence of optimal operation conditions for minimum fuel consumption of the gas turbine based combined cycle cogeneration power plant. Optimal operational condition means the optimal distribution of the power generated by each gas turbine and the heat generated by each HRSG. Total fuel consumption is calculated by the sum of the fuels for gas turbines and supplementary boiler. Fuel consumption is calculated by numerical methods of energy equations which contain the power generated from gas and steam turbines, the heat generated by HRSG and the heat extracted from high pressure steam turbine

  6. Fatigue Analysis of Casted Hubs in Wind Turbines

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Nielsen, Søren R.K.; Sørensen, Steffen

    2002-01-01

    The hub of a wind turbine rotor is excited by time-varying forces and moments from the blades caused by extemal dynamic loads such as wind loading and aeroelastic effects. The paper describes how reliability-based fatigue analysis can be made based on SN-curves and how reliability-based inspection...

  7. Evaluation of RCAS Inflow Models for Wind Turbine Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Tangler, J.; Bir, G.

    2004-02-01

    The finite element structural modeling in the Rotorcraft Comprehensive Analysis System (RCAS) provides a state-of-the-art approach to aeroelastic analysis. This, coupled with its ability to model all turbine components, results in a methodology that can simulate complex system interactions characteristic of large wind. In addition, RCAS is uniquely capable of modeling advanced control algorithms and the resulting dynamic responses.

  8. Laboratory Studies of the Effects of Pressure and Dissolved Gas Supersaturation on Turbine-Passed Fish

    International Nuclear Information System (INIS)

    Abernethy, Cary S; Amidan, Brett G

    2001-01-01

    The objective of this study was to examine the relative importance of pressure changes as a source of turbine-passage injury and mortality. Specific tests were designed to quantify the response of fish to rapid pressure changes typical of turbine passage, with and without the complication of the fish being acclimated to gas supersaturated water. We investigated the responses of rainbow trout (Oncorhynchus mykiss), chinook salmon (O. tshawytscha), and bluegill sunfish (Lepomis macrochirus) to these two stresses, both singly and in combination

  9. NEXT GENERATION GAS TURBINE (NGGT) SYSTEMS STUDY; FINAL

    International Nuclear Information System (INIS)

    Unknown

    2001-01-01

    Building upon the 1999 AD Little Study, an expanded market analysis was performed by GE Power Systems in 2001 to quantify the potential demand for an NGGT product. This analysis concluded that improvements to the US energy situation might be best served in the near/mid term (2002-2009) by a ''Technology-Focused'' program rather than a specific ''Product-Focused'' program. Within this new program focus, GEPS performed a parametric screening study of options in the three broad candidate categories of gas turbines: aero-derivative, heavy duty, and a potential hybrid combining components of the other two categories. GEPS's goal was to determine the best candidate systems that could achieve the DOE PRDA expectations and GEPS's internal design criteria in the period specified for initial product introduction, circa 2005. Performance feasibility studies were conducted on candidate systems selected in the screening task, and critical technology areas were identified where further development would be required to meet the program goals. DOE PRDA operating parameters were found to be achievable by 2005 through evolutionary technology. As a result, the study was re-directed toward technology enhancements for interim product introductions and advanced/revolutionary technology for potential NGGT product configurations. Candidate technologies were identified, both evolutionary and revolutionary, with a potential for possible development products via growth step improvements. Benefits were analyzed from two perspectives: (1) What would be the attributes of the top candidate system assuming the relevant technologies were developed and available for an NGGT market opportunity in 2009/2010; and (2) What would be the expected level of public benefit, assuming relevant technologies were incorporated into existing new and current field products as they became available. Candidate systems incorporating these technologies were assessed as to how they could serve multiple applications

  10. Feasibility Study of Micro-Wind Turbines for Powering Wireless Sensors on a Cable-Stayed Bridge

    Directory of Open Access Journals (Sweden)

    Billie F. Spencer

    2012-09-01

    Full Text Available In this study, the feasibility of using micro-wind turbines to power wireless sensors on a cable-stayed bridge is comprehensively investigated. To this end, the wind environment around a bridge onto which a turbine is installed is examined, as is the power consumption of a wireless sensor. Feasible alternators and rotors are then carefully selected to make an effective small wind generator (known as a micro-wind turbine. Using the three specially selected micro-wind turbines, a series of experiments was conducted to find the turbine best able to generate the largest amount of power. Finally, a horizontal-axis micro-wind turbine with a six-blade rotor was combined with a wireless sensor to validate experimentally its actual power-charging capability. It is demonstrated that the micro-wind turbine can generate sufficient electricity to power a wireless sensor under moderate wind conditions.

  11. Study on Creep Damage Model of 1Cr1Mo1/4V Steel for Turbine Rotor

    International Nuclear Information System (INIS)

    Choi, Woo Sung; Song, Gee Wook; Kim, Bum Shin; Chang, Sung Ho; Fleury, Eric

    2011-01-01

    It is well known that the dominant damage mechanisms in high-temperature steam turbine facilities such as rotor and casing are creep and fatigue damages. Even though coupling of creep and fatigue should be considered while predicting the life of turbine facilities, the remaining life of large steam turbine facilities is generally determined on the basis of creep damage because the turbines must generate stable base-load power and because they are operated at a high temperature and pressure for a long time. Almost every large steam turbine in Korea has been operated for more than 20 years and is made of steel containing various amounts of principal alloying elements nickel, chromium, molybdenum, and vanadium. In this study, creep damage model of 1Cr1Mo1/4V steel for turbine rotor is proposed and that can assess the high temperature creep life of large steam turbine facilities is proposed

  12. Occupational Health and Industrial Wind Turbines: A Case Study

    Science.gov (United States)

    Rand, Robert W.; Ambrose, Stephen E.; Krogh, Carmen M. E.

    2011-01-01

    Industrial wind turbines (IWTs) are being installed at a fast pace globally. Researchers, medical practitioners, and media have reported adverse health effects resulting from living in the environs of IWTs. While there have been some anecdotal reports from technicians and other workers who work in the environs of IWTs, little is known about the…

  13. Preliminary modelling study of ice accretion on wind turbines

    DEFF Research Database (Denmark)

    Pedersen, Marie Cecilie; Yin, Chungen

    2014-01-01

    One of the main challenges associated with cold-climate wind energy is icing on wind turbines and a series of icing-induced problems such as production loss, blade fatigue and safety issues. Because of the difficulties with on-site measurements, simulations are often used to understand and predic...

  14. Study on Parameters Modeling of Wind Turbines Using SCADA Data

    Directory of Open Access Journals (Sweden)

    Yonglong YAN

    2014-08-01

    Full Text Available Taking the advantage of the current massive monitoring data from Supervisory Control and Data Acquisition (SCADA system of wind farm, it is of important significance for anomaly detection, early warning and fault diagnosis to build the data model of state parameters of wind turbines (WTs. The operational conditions and the relationships between the state parameters of wind turbines are complex. It is difficult to establish the model of state parameter accurately, and the modeling method of state parameters of wind turbines considering parameter selection is proposed. Firstly, by analyzing the characteristic of SCADA data, a reasonable range of data and monitoring parameters are chosen. Secondly, neural network algorithm is adapted, and the selection method of input parameters in the model is presented. Generator bearing temperature and cooling air temperature are regarded as target parameters, and the two models are built and input parameters of the models are selected, respectively. Finally, the parameter selection method in this paper and the method using genetic algorithm-partial least square (GA-PLS are analyzed comparatively, and the results show that the proposed methods are correct and effective. Furthermore, the modeling of two parameters illustrate that the method in this paper can applied to other state parameters of wind turbines.

  15. A Numerical Study on a Vertical-Axis Wind Turbine with Inclined Arms

    Directory of Open Access Journals (Sweden)

    Agostino De Marco

    2014-01-01

    Full Text Available This work focuses on a particular type of vertical-axis wind turbine, in which a number of inclined arms with airfoil-shaped cross-sections are mounted to connect the principal blades to their hub. While the majority of the known studies on vertical-axis turbines is devoted to the role of principal blades, in most of the cases without taking into account other parts of the wind turbine, the objective of this work is to investigate the effect of uncommon arm geometries, such as the inclined arms. The inclined arms are known to have a potentially beneficial role in the power extraction from the wind current but, due to the complexity of the phenomena, the investigation on aerodynamics of this type of turbine is often impossible through analytical models, such as blade-element momentum theory. It turns out that adequate studies can only be carried out by wind tunnel experiments or CFD simulations. This work presents a methodical CFD study on how inclined arms can be used on a selected wind turbine configuration to harvest additional power from the wind. The turbine configuration, geometry, and some fundamental definitions are introduced first. Then an in-depth CFD analysis is presented and discussed.

  16. Frequency support capability of variable speed wind turbine based on electromagnetic coupler

    DEFF Research Database (Denmark)

    You, Rui; Barahona Garzón, Braulio; Chai, Jianyun

    2015-01-01

    capability has to be enhanced. In this paper, the frequency support capability of WT-EMC is studied at three typical wind conditions and with two control strategies-droop control and inertial control to enhance its frequency support capability. The synchronous generator speed, more stable than the grid......In the variable speed wind turbine based on electromagnetic coupler (WT-EMC), a synchronous generator is directly coupled with grid. So like conventional power plants WT-EMC is able to support grid frequency inherently. But due to the reduced inertia of synchronous generator, its frequency support...... frequency which is the input signal for Type 3 and Type 4 wind turbine frequency support controller, is used for the calculation of WT-EMC supplementary torque command. The integrated simulation environment based on the aeroelastic code HAWC2 and software Matlab/Simulink is used to build a 2 MW WT-EMC model...

  17. Compensatory hypertrophy of the contralateral inferior turbinate in patients with unilateral nasal septal deviation. A computed tomography study.

    Science.gov (United States)

    Chiesa Estomba, Carlos; Rivera Schmitz, Teresa; Ossa Echeverri, Carla C; Betances Reinoso, Frank A; Osorio Velasquez, Alejandra; Santidrian Hidalgo, Carmelo

    2015-01-01

    The compensatory hypertrophy of the inferior turbinate in patients with septal deviation to one of the nostrils is considered to protect the airways from the excess of air that could enter through the nostril and its potential negative effects such as dryness, alteration of air filtration, mucociliary flow, or lung involvement. A prospective, longitudinal, non-randomized study. Patients were divided in two groups: 10 consecutive patients, with nasal septal deviation and compensatory hypertrophy of the inferior turbinate in the contralateral nasal cavity (10 non-hypertrophied turbinates as control and 10 contralateral hypertrophied turbinates as study cases), and the second group with 5 patients without any nasal pathology (10 turbinates without any obvious pathology). In both groups CT scans of the nasal region were performed. A comparison of patients with nasal septal deviation with compensatory hypertrophy of the inferior turbinate in the contralateral nasal cavity and with non-pathological inferior turbinate was carried out. When analyzing the groups of patients with septal deviation, the contralateral hypertrophied turbinate and the non-hypertrophied turbinate side, we found a significant hypertrophy in the anterior portion of the inferior turbinate, at the level of the medial mucosa (P = 0.002) and bone (P = 0.001) in the group of patients with contralateral hypertrophied turbinate. However, when we compared the contralateral hypertrophic turbinate with the turbinate of patients without septal deviation, we found a significant difference in all volumes of the medial and lateral mucosa and the bone portion (P = 0.001, P = 0.005). Surgical correction of the nasal septum and lateralization or reduction of the volume of the inferior turbinate (which may include the medial mucosa, head or part of the bone) is necessary in order to improve air passage into the nasal valve.

  18. Comparison of two LES codes for wind turbine wake studies

    Science.gov (United States)

    Sarlak, H.; Pierella, F.; Mikkelsen, R.; Sørensen, J. N.

    2014-06-01

    For the third time a blind test comparison in Norway 2013, was conducted comparing numerical simulations for the rotor Cp and Ct and wake profiles with the experimental results. As the only large eddy simulation study among participants, results of the Technical University of Denmark (DTU) using their in-house CFD solver, EllipSys3D, proved to be more reliable among the other models for capturing the wake profiles and the turbulence intensities downstream the turbine. It was therefore remarked in the workshop to investigate other LES codes to compare their performance with EllipSys3D. The aim of this paper is to investigate on two CFD solvers, the DTU's in-house code, EllipSys3D and the open-sourse toolbox, OpenFoam, for a set of actuator line based LES computations. Two types of simulations are performed: the wake behind a signle rotor and the wake behind a cluster of three inline rotors. Results are compared in terms of velocity deficit, turbulence kinetic energy and eddy viscosity. It is seen that both codes predict similar near-wake flow structures with the exception of OpenFoam's simulations without the subgrid-scale model. The differences begin to increase with increasing the distance from the upstream rotor. From the single rotor simulations, EllipSys3D is found to predict a slower wake recovery in the case of uniform laminar flow. From the 3-rotor computations, it is seen that the difference between the codes is smaller as the disturbance created by the downstream rotors causes break down of the wake structures and more homogenuous flow structures. It is finally observed that OpenFoam computations are more sensitive to the SGS models.

  19. Nonlinear aeroelastic behavior of compliant airfoils

    International Nuclear Information System (INIS)

    Thwapiah, G; Campanile, L F

    2010-01-01

    Since the beginning of aviation and up to the present time, airfoils have always been built as rigid structures. They are designed to fly under their divergence speed in order to avoid static aeroelastic instabilities and the resulting large deformations, which are not compatible with the typically low compliance of such airfoils. In recent years, research on airfoil morphing has generated interest in innovative ideas like the use of compliant systems, i.e. systems built to allow for large deformations without failure, in airfoil construction. Such systems can operate in the neighborhood of divergence and take advantage of large aeroelastic servo-effects. This, in turn, allows compact, advanced actuators to control the airfoil's deformation and loads, and hence complement or even replace conventional flaps. In order to analyze and design such compliant, active aeroelastic structures a nonlinear approach to static aeroelasticity is needed, which takes into account the effect of large deformations on aerodynamics and structure. Such an analytical approach is presented in this paper and applied to a compliant passive airfoil as the preliminary step in the realization of a piezoelectrically driven, active aeroelastic airfoil. Wind tunnel test results are also presented and compared with the analytic prediction. The good agreement and the observed behavior in the wind tunnel give confidence in the potential of this innovative idea

  20. Nonlinear aeroelastic behavior of compliant airfoils

    Science.gov (United States)

    Thwapiah, G.; Campanile, L. F.

    2010-03-01

    Since the beginning of aviation and up to the present time, airfoils have always been built as rigid structures. They are designed to fly under their divergence speed in order to avoid static aeroelastic instabilities and the resulting large deformations, which are not compatible with the typically low compliance of such airfoils. In recent years, research on airfoil morphing has generated interest in innovative ideas like the use of compliant systems, i.e. systems built to allow for large deformations without failure, in airfoil construction. Such systems can operate in the neighborhood of divergence and take advantage of large aeroelastic servo-effects. This, in turn, allows compact, advanced actuators to control the airfoil's deformation and loads, and hence complement or even replace conventional flaps. In order to analyze and design such compliant, active aeroelastic structures a nonlinear approach to static aeroelasticity is needed, which takes into account the effect of large deformations on aerodynamics and structure. Such an analytical approach is presented in this paper and applied to a compliant passive airfoil as the preliminary step in the realization of a piezoelectrically driven, active aeroelastic airfoil. Wind tunnel test results are also presented and compared with the analytic prediction. The good agreement and the observed behavior in the wind tunnel give confidence in the potential of this innovative idea.

  1. Aeroelastic Optimization Design for High-Aspect-Ratio Wings with Large Deformation

    Directory of Open Access Journals (Sweden)

    Changchuan Xie

    2017-01-01

    Full Text Available This paper presents a framework of aeroelastic optimization design for high-aspect-ratio wing with large deformation. A highly flexible wing model for wind tunnel test is optimized subjected to multiple aeroelastic constraints. Static aeroelastic analysis is carried out for the beamlike wing model, using a geometrically nonlinear beam formulation coupled with the nonplanar vortex lattice method. The flutter solutions are obtained using the P-K method based on the static equilibrium configuration. The corresponding unsteady aerodynamic forces are calculated by nonplanar doublet-lattice method. This paper obtains linear and nonlinear aeroelastic optimum results, respectively, by the ISIGHT optimization platform. In this optimization problem, parameters of beam cross section are chosen as the design variables to satisfy the displacement, flutter, and strength requirements, while minimizing wing weight. The results indicate that it is necessary to consider geometrical nonlinearity in aeroelastic optimization design. In addition, optimization strategies are explored to simplify the complex optimization process and reduce the computing time. Different criterion values are selected and studied for judging the effects of the simplified method on the computing time and the accuracy of results. In this way, the computing time is reduced by more than 30% on the premise of ensuring the accuracy.

  2. Controlled aeroelastic response and airfoil shaping using adaptive materials and integrated systems

    Science.gov (United States)

    Pinkerton, Jennifer L.; McGowan, Anna-Maria R.; Moses, Robert W.; Scott, Robert C.; Heeg, Jennifer

    1996-05-01

    This paper presents an overview of several activities of the Aeroelasticity Branch at the NASA Langley Research Center in the area of applying adaptive materials and integrated systems for controlling both aircraft aeroelastic response and airfoil shape. The experimental results of four programs are discussed: the Piezoelectric Aeroelastic Response Tailoring Investigation (PARTI); the adaptive neural control of aeroelastic response (ANCAR) program; the actively controlled response of buffet affected tails (ACROBAT) program; and the Airfoil THUNDER Testing to ascertain charcteristics (ATTACH) project. The PARTI program demonstrated active flutter control and significant reductions in aeroelastic response at dynamic pressures below flutter using piezoelectric actuators. The ANCAR program seeks to demonstrate the effectiveness of using neural networks to schedule flutter suppression control laws. The ACROBAT program studied the effectiveness of a number of candidate actuators, including a rudder and piezoelectric actuators, to alleviate vertical tail buffeting. In the ATTACH project, the feasibility of using thin-layer composite-unimorph piezoelectric driver and sensor (THUNDER) wafers to control airfoil aerodynamic characteristics was investigated. Plans for future applications are also discussed.

  3. Engine Power Turbine and Propulsion Pod Arrangement Study

    Science.gov (United States)

    Robuck, Mark; Zhang, Yiyi

    2014-01-01

    A study has been conducted for NASA Glenn Research Center under contract NNC10BA05B, Task NNC11TA80T to identify beneficial arrangements of the turboshaft engine, transmissions and related systems within the propulsion pod nacelle of NASA's Large Civil Tilt-Rotor 2nd iteration (LCTR2) vehicle. Propulsion pod layouts were used to investigate potential advantages, disadvantages, as well as constraints of various arrangements assuming front or aft shafted engines. Results from previous NASA LCTR2 propulsion system studies and tasks performed by Boeing under NASA contracts are used as the basis for this study. This configuration consists of two Fixed Geometry Variable Speed Power Turbine Engines and related drive and rotor systems (per nacelle) arranged in tilting nacelles near the wing tip. Entry-into-service (EIS) 2035 technology is assumed for both the engine and drive systems. The variable speed rotor system changes from 100 percent speed for hover to 54 percent speed for cruise by the means of a two speed gearbox concept developed under previous NASA contracts. Propulsion and drive system configurations that resulted in minimum vehicle gross weight were identified in previous work and used here. Results reported in this study illustrate that a forward shafted engine has a slight weight benefit over an aft shafted engine for the LCTR2 vehicle. Although the aft shafted engines provide a more controlled and centered CG (between hover and cruise), the length of the long rotor shaft and complicated engine exhaust arrangement outweighed the potential benefits. A Multi-Disciplinary Analysis and Optimization (MDAO) approach for transmission sizing was also explored for this study. This tool offers quick analysis of gear loads, bearing lives, efficiencies, etc., through use of commercially available RomaxDESIGNER software. The goal was to create quick methods to explore various concept models. The output results from RomaxDESIGNER have been successfully linked to Boeing

  4. Testing and Modeling of a 3-MW Wind Turbine Using Fully Coupled Simulation Codes (Poster)

    Energy Technology Data Exchange (ETDEWEB)

    LaCava, W.; Guo, Y.; Van Dam, J.; Bergua, R.; Casanovas, C.; Cugat, C.

    2012-06-01

    This poster describes the NREL/Alstom Wind testing and model verification of the Alstom 3-MW wind turbine located at NREL's National Wind Technology Center. NREL,in collaboration with ALSTOM Wind, is studying a 3-MW wind turbine installed at the National Wind Technology Center(NWTC). The project analyzes the turbine design using a state-of-the-art simulation code validated with detailed test data. This poster describes the testing and the model validation effort, and provides conclusions about the performance of the unique drive train configuration used in this wind turbine. The 3-MW machine has been operating at the NWTC since March 2011, and drive train measurements will be collected through the spring of 2012. The NWTC testing site has particularly turbulent wind patterns that allow for the measurement of large transient loads and the resulting turbine response. This poster describes the 3-MW turbine test project, the instrumentation installed, and the load cases captured. The design of a reliable wind turbine drive train increasingly relies on the use of advanced simulation to predict structural responses in a varying wind field. This poster presents a fully coupled, aero-elastic and dynamic model of the wind turbine. It also shows the methodology used to validate the model, including the use of measured tower modes, model-to-model comparisons of the power curve, and mainshaft bending predictions for various load cases. The drivetrain is designed to only transmit torque to the gearbox, eliminating non-torque moments that are known to cause gear misalignment. Preliminary results show that the drivetrain is able to divert bending loads in extreme loading cases, and that a significantly smaller bending moment is induced on the mainshaft compared to a three-point mounting design.

  5. Aeroelastic large eddy simulations using vortex methods: unfrozen turbulent and sheared inflow

    DEFF Research Database (Denmark)

    Branlard, Emmanuel Simon Pierre; Papadakis, G.; Gaunaa, Mac

    2015-01-01

    Vortex particles methods are applied to the aeroelastic simulation of a wind turbine in sheared and turbulent inflow. The possibility to perform large-eddy simulations of turbulence with the effect of the shear vorticity is demonstrated for the first time in vortex methods simulations. Most vortex...... methods formulation of shear, including segment formulations, assume a frozen shear. It is here shown that these formulations omit two source terms in the vorticity equation. The current paper also present unfrozen simulation of shear. The infinite support of the shear vorticity is accounted for using...

  6. Structure Detection of Nonlinear Aeroelastic Systems with Application to Aeroelastic Flight Test Data. Part 1

    Science.gov (United States)

    Kukreja, Sunil L.; Brenner, Martin J.

    2006-01-01

    This viewgraph presentation reviews the applicability of NARMAX structure detection to aeroelastic systems. In conclusion, the simulation results demonstrate bootstrap approach for structure computation of aircraft structural stiffness provided a high rate of true model selection: 1. T-test and stepwise regression methods had difficulty providing accurate results 2. Work contributes to understanding of the use of structure detection for modelling and identification of aerospace systems. 3. Limitation of model complexity that can be studied with these structure computation techniques 4. Result of the large number of candidate terms, for a given model order, and the data length required to guarantee convergence 5. Another approach to structure computation problem uses a least absolute shrinkage and selection operator (LASSO)

  7. Structure Detection of Nonlinear Aeroelastic Systems with Application to Aeroelastic Flight Test Data. Part 2

    Science.gov (United States)

    Kukreja, Sunil L.; Brenner, martin J.

    2006-01-01

    This viewgraph presentation reviews the 1. Motivation for the study 2. Nonlinear Model Form 3. Structure Detection 4. Least Absolute Shrinkage and Selection Operator (LASSO) 5. Objectives 6. Results 7. Assess LASSO as a Structure Detection Tool: Simulated Nonlinear Models 8. Applicability to Complex Systems: F/A-18 Active Aeroelastic Wing Flight Test Data. The authors conclude that 1. this is a novel approach for detecting the structure of highly over-parameterised nonlinear models in situations where other methods may be inadequate 2. that it is a practical significance in the analysis of aircraft dynamics during envelope expansion and could lead to more efficient control strategies and 3. this could allow greater insight into the functionality of various systems dynamics, by providing a quantitative model which is easily interpretable

  8. Sensor comparison study for load alleviating wind turbine pitch control

    DEFF Research Database (Denmark)

    Kragh, Knud Abildgaard; Hansen, Morten Hartvig; Henriksen, Lars Christian

    2014-01-01

    of angle of attack and relative velocity at a radial position of the blades, and upstream inflow measurements from a spinner mounted light detection and ranging (LiDAR) sensor that enables preview of the incoming flow field. The results show that for stationary inflow conditions, the three different......As the size of wind turbines increases, the load alleviating capabilities of the turbine controller are becoming increasingly important. Load alleviating control schemes have traditionally been based on feedback from load sensor; however, recent developments of measurement technologies have enabled...... control on the basis of preview measurements of the inflow acquired using, e.g., light detection and ranging. The potential of alleviating load variations that are caused by mean wind speed changes through feed-forward control have been demonstrated through both experiments and simulations in several...

  9. Aerodynamic study of a small horizontal-axis wind turbine

    Directory of Open Access Journals (Sweden)

    Cornelia NITA

    2012-06-01

    Full Text Available The wind energy is deemed as one of the most durable energetic variants of the future because the wind resources are immense. Furthermore, one predicts that the small wind turbine will play a vital role in the urban environment. Unfortunately, nowadays, the noise emissions from wind turbines represent one of the main obstacles to widespread the use in populated zones. Moreover, the energetic efficiency of these wind turbines has to be high even at low and medium wind velocities because, usually the cities are not windy places. The numerical results clearly show that the wakes after the trailing edge are the main noise sources. In order to decrease the power of these noise sources, we should try to decrease the intensity of wakes after the trailing edge, i.e. the aerodynamic fields from pressure and suction sides would have to be almost the same near trailing edge. Furthermore, one observes a strong link between transport (circumferential velocity and acoustic power level, i.e. if the transport velocity increases, the acoustic power level also augments.

  10. Wind Turbine Gearbox Condition Monitoring Round Robin Study - Vibration Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Sheng, S.

    2012-07-01

    The Gearbox Reliability Collaborative (GRC) at the National Wind Technology Center (NWTC) tested two identical gearboxes. One was tested on the NWTCs 2.5 MW dynamometer and the other was field tested in a turbine in a nearby wind plant. In the field, the test gearbox experienced two oil loss events that resulted in damage to its internal bearings and gears. Since the damage was not severe, the test gearbox was removed from the field and retested in the NWTCs dynamometer before it was disassembled. During the dynamometer retest, some vibration data along with testing condition information were collected. These data enabled NREL to launch a Wind Turbine Gearbox Condition Monitoring Round Robin project, as described in this report. The main objective of this project was to evaluate different vibration analysis algorithms used in wind turbine condition monitoring (CM) and find out whether the typical practices are effective. With involvement of both academic researchers and industrial partners, the project sets an example on providing cutting edge research results back to industry.

  11. Experimental/Numerical Comparison of Turbine Efficiency and Wake Structure in an Array of 3 Scale-Model Marine Hydrokinetic Turbines

    Science.gov (United States)

    Sale, Danny; Bates, John; Polagye, Brian; Aliseda, Alberto

    2015-11-01

    Numerical simulations and experiments are conducted for axial-flow Marine Hydro-Kinetic (MHK) turbines operating in a flume. This study aims to understand the influence of coherent structures in high Reynolds number wakes on energy extraction and dynamical rotor control processes. In experiments, rotor torque and rotational position measurements are collected, and the flow field characterized by simultaneous imaging with particle image velocimetry. The performance of 3 turbines are characterized under varying downstream spacing and lateral offsets. To study effects of unsteady hydrodynamics, the turbines are outfitted with open-loop and close-loop feedback controls and compared to the case of uncontrolled rotor. In numerical simulations, different tiers of turbine models are evaluated to discern tradeoffs in fidelity to physics versus cost. Analogous ``actuator methods'' are included from Large-Eddy-Simulations and Reynolds-Averaged-Navier-Stokes, where the models impose body forces upon the flow field in form of disks, lines, or surfaces. An aeroelastic model coupled to LES predicts the dynamical response of rotors to upstream wakes and ambient turbulence. These comparative studies inform how simulations can be scaled up to inform design of utility-scale MHK power plants.

  12. Renaissance of Aeroelasticity and Its Future

    Science.gov (United States)

    Friedmann, Peretz P.

    1999-01-01

    The primary objective of this paper is to demonstrate that the field of aeroelasticity continues to play a critical role in the design of modern aerospace vehicles, and several important problems are still far from being well understood. Furthermore, the emergence of new technologies, such as the use of adaptive materials (sometimes denoted as smart structures technology), providing new actuator and sensor capabilities, has invigorated aeroelasticity, and generated a host of new and challenging research topics that can have a major impact on the design of a new generation of aerospace vehicles.

  13. Failure rate modeling using fault tree analysis and Bayesian network: DEMO pulsed operation turbine study case

    International Nuclear Information System (INIS)

    Dongiovanni, Danilo Nicola; Iesmantas, Tomas

    2016-01-01

    Highlights: • RAMI (Reliability, Availability, Maintainability and Inspectability) assessment of secondary heat transfer loop for a DEMO nuclear fusion plant. • Definition of a fault tree for a nuclear steam turbine operated in pulsed mode. • Turbine failure rate models update by mean of a Bayesian network reflecting the fault tree analysis in the considered scenario. • Sensitivity analysis on system availability performance. - Abstract: Availability will play an important role in the Demonstration Power Plant (DEMO) success from an economic and safety perspective. Availability performance is commonly assessed by Reliability Availability Maintainability Inspectability (RAMI) analysis, strongly relying on the accurate definition of system components failure modes (FM) and failure rates (FR). Little component experience is available in fusion application, therefore requiring the adaptation of literature FR to fusion plant operating conditions, which may differ in several aspects. As a possible solution to this problem, a new methodology to extrapolate/estimate components failure rate under different operating conditions is presented. The DEMO Balance of Plant nuclear steam turbine component operated in pulse mode is considered as study case. The methodology moves from the definition of a fault tree taking into account failure modes possibly enhanced by pulsed operation. The fault tree is then translated into a Bayesian network. A statistical model for the turbine system failure rate in terms of subcomponents’ FR is hence obtained, allowing for sensitivity analyses on the structured mixture of literature and unknown FR data for which plausible value intervals are investigated to assess their impact on the whole turbine system FR. Finally, the impact of resulting turbine system FR on plant availability is assessed exploiting a Reliability Block Diagram (RBD) model for a typical secondary cooling system implementing a Rankine cycle. Mean inherent availability

  14. Influence of atmospheric stability on wind-turbine wakes: A large-eddy simulation study

    Science.gov (United States)

    Abkar, Mahdi; Porté-Agel, Fernando

    2014-05-01

    In this study, large-eddy simulation is combined with a turbine model to investigate the influence of atmospheric stability on wind-turbine wakes. In the simulations, subgrid-scale turbulent fluxes are parameterized using tuning-free Lagrangian scale-dependent dynamic models. These models optimize the local value of the model coefficients based on the dynamics of the resolved scales. The turbine-induced forces are parameterized with an actuator-disk model with rotation. In this technique, blade-element theory is used to calculate the lift and drag forces acting on the blades. Emphasis is placed on the structure and characteristics of wind-turbine wakes in the cases where the incident flows to the turbine have the same mean velocity at the hub height but different stability conditions. The simulation results show that atmospheric stability has a significant effect on the spatial distribution of the mean velocity deficit and turbulent fluxes in the wake region. In particular, the magnitude of the velocity deficit increases with increasing stability in the atmosphere. In addition, the locations of the maximum turbulence intensity and turbulent stresses are closer to the turbine in convective boundary layer compared with neutral and stable ones. Detailed analysis of the resolved turbulent kinetic energy (TKE) budget inside the wake reveals also that the thermal stratification of the incoming wind considerably affects the magnitude and spatial distribution of the turbulent production, transport term and dissipation rate (transfer of energy to the subgrid scales). It is also shown that the near-wake region can be extended to a farther distance downstream in stable condition compared with neutral and unstable counterparts. In order to isolate the effect of atmospheric stability, additional simulations of neutrally-stratified atmospheric boundary layers are performed with the same turbulence intensity at hub height as convective and stable ones. The results show that the

  15. Failure rate modeling using fault tree analysis and Bayesian network: DEMO pulsed operation turbine study case

    Energy Technology Data Exchange (ETDEWEB)

    Dongiovanni, Danilo Nicola, E-mail: danilo.dongiovanni@enea.it [ENEA, Nuclear Fusion and Safety Technologies Department, via Enrico Fermi 45, Frascati 00040 (Italy); Iesmantas, Tomas [LEI, Breslaujos str. 3 Kaunas (Lithuania)

    2016-11-01

    Highlights: • RAMI (Reliability, Availability, Maintainability and Inspectability) assessment of secondary heat transfer loop for a DEMO nuclear fusion plant. • Definition of a fault tree for a nuclear steam turbine operated in pulsed mode. • Turbine failure rate models update by mean of a Bayesian network reflecting the fault tree analysis in the considered scenario. • Sensitivity analysis on system availability performance. - Abstract: Availability will play an important role in the Demonstration Power Plant (DEMO) success from an economic and safety perspective. Availability performance is commonly assessed by Reliability Availability Maintainability Inspectability (RAMI) analysis, strongly relying on the accurate definition of system components failure modes (FM) and failure rates (FR). Little component experience is available in fusion application, therefore requiring the adaptation of literature FR to fusion plant operating conditions, which may differ in several aspects. As a possible solution to this problem, a new methodology to extrapolate/estimate components failure rate under different operating conditions is presented. The DEMO Balance of Plant nuclear steam turbine component operated in pulse mode is considered as study case. The methodology moves from the definition of a fault tree taking into account failure modes possibly enhanced by pulsed operation. The fault tree is then translated into a Bayesian network. A statistical model for the turbine system failure rate in terms of subcomponents’ FR is hence obtained, allowing for sensitivity analyses on the structured mixture of literature and unknown FR data for which plausible value intervals are investigated to assess their impact on the whole turbine system FR. Finally, the impact of resulting turbine system FR on plant availability is assessed exploiting a Reliability Block Diagram (RBD) model for a typical secondary cooling system implementing a Rankine cycle. Mean inherent availability

  16. Lewis Research Center studies of multiple large wind turbine generators on a utility network

    Science.gov (United States)

    Gilbert, L. J.; Triezenberg, D. M.

    1979-01-01

    A NASA-Lewis program to study the anticipated performance of a wind turbine generator farm on an electric utility network is surveyed. The paper describes the approach of the Lewis Wind Energy Project Office to developing analysis capabilities in the area of wind turbine generator-utility network computer simulations. Attention is given to areas such as, the Lewis Purdue hybrid simulation, an independent stability study, DOE multiunit plant study, and the WEST simulator. Also covered are the Lewis mod-2 simulation including analog simulation of a two wind turbine system and comparison with Boeing simulation results, and gust response of a two machine model. Finally future work to be done is noted and it is concluded that the study shows little interaction between the generators and between the generators and the bus.

  17. Interactive aircraft flight control and aeroelastic stabilization

    Science.gov (United States)

    Weisshaar, T. A.

    1985-01-01

    Aeroservoelastic optimization techniques were studied to determine a methodology for maximization of the stable flight envelope of an idealized, actively controlled, flexible airfoil. The equations of motion for the airfoil were developed in state-space form to include time-domain representations of aerodynamic forces and active control. The development of an optimization scheme to stabilize the aeroelastic system over a range of airspeeds, including the design airspeed is outlined. The solution approach was divided in two levels: (1) the airfoil structure, with a design variable represented by the shear center position; and (2) the control system. An objective was stated in mathematical form and a search was conducted with the restriction that each subsystem be constrained to be optimal in some sense. Analytical expressions are developed to compute the changes in the eigenvalues of the closed-loop, actively controlled system. A stability index is constructed to ensure that stability is present at the design speed and at other airspeeds away from the design speed.

  18. Study on Unified Chaotic System-Based Wind Turbine Blade Fault Diagnostic System

    Science.gov (United States)

    Kuo, Ying-Che; Hsieh, Chin-Tsung; Yau, Her-Terng; Li, Yu-Chung

    At present, vibration signals are processed and analyzed mostly in the frequency domain. The spectrum clearly shows the signal structure and the specific characteristic frequency band is analyzed, but the number of calculations required is huge, resulting in delays. Therefore, this study uses the characteristics of a nonlinear system to load the complete vibration signal to the unified chaotic system, applying the dynamic error to analyze the wind turbine vibration signal, and adopting extenics theory for artificial intelligent fault diagnosis of the analysis signal. Hence, a fault diagnostor has been developed for wind turbine rotating blades. This study simulates three wind turbine blade states, namely stress rupture, screw loosening and blade loss, and validates the methods. The experimental results prove that the unified chaotic system used in this paper has a significant effect on vibration signal analysis. Thus, the operating conditions of wind turbines can be quickly known from this fault diagnostic system, and the maintenance schedule can be arranged before the faults worsen, making the management and implementation of wind turbines smoother, so as to reduce many unnecessary costs.

  19. An Experimental Study of Lightning Overvoltages in Wind Turbine Generation Systems

    Science.gov (United States)

    Yamamoto, Kazuo; Ohta, Tomokatsu; Noda, Taku; Yokoyama, Shigeru; Ametani, Akihiro

    In order to obtain good wind conditions, wind turbine generation systems are built at places like hill countries and shorefronts where few tall structures are found. However, this increases the risk of lightning strikes. To promote wind power generation, lightning-protection methodologies for such wind turbine generation systems have to be established. This paper presents the results of an experimental study which investigates the lightning overvoltages in wind turbine generation systems. The experiments were carried out on actual ground soil using a reduced-size wind turbine model with its foundations. From the experiments, the following conclusions have been deduced: (i) Voltage rise due to the grounding impedance of the foundations can cause a significant overvoltage between the tower foot and an incoming cable like a power, a communication or a control line. (ii) The voltage rise of the foundations and that of the surrounding ground soil may cause an overvoltage at the outermost insulation layer of an incoming cable, which can result in a breakdown or a deterioration of the insulation (iii) Voltage and current waveforms to understand the traveling-wave phenomenon on a wind power generation system with its foundations were obtained. The data will be useful for developing an EMTP simulation model of a wind turbine generation system for lightning overvoltage studies.

  20. Bulb turbine operating at medium head: XIA JIANG case study

    Science.gov (United States)

    Loiseau, F.; Desrats, C.; Petit, P.; Liu, J.

    2012-11-01

    With lots of references for 4-blade bulb turbines, such as these of Wu Jin Xia (4 units - 36.1 MW per unit - 9.2 m rated head), Chang Zhou (15 units - 46.7 MW per unit - 9.5 m rated head) and Tong Wan (4 units - 46.2 MW per unit - 11 m rated head), ALSTOM Power Hydro is one of the major suppliers of bulb turbines operating under medium head for the Chinese market. ALSTOM Power Hydro has been awarded in November 2010 a contract by Jiang Xi Province Xia Jiang Water Control Project Headquarters to equip Xia Jiang's new hydropower plant. The power dam is located on the Gan Jiang river, at about 160 km away from Nan Chang town in South Eastern China. The supply will consist in 5 bulb units including the furniture of both the turbine and its generator, for a total capacity of 200 MW, under a rated net head of 8.6 m. The prototype turbine is a 7.8 m diameter runner, rotating at 71.4 rpm speed. For this project, ALSTOM has proposed a fully new design of 4-blade bulb runner. This paper outlines the main steps of the hydraulic development. First of all, a fine tuning of the blade geometry was performed to enhance the runner behaviour at high loads and low heads, so that to fulfill the demanding requirements of efficiencies and maximum output. The challenge was also to keep an excellent cavitation behaviour, especially at the outer blade diameter in order to avoid cavitation erosion on the prototype. The shape of the blade was optimized by using the latest tools in computational fluid dynamics. Steady state simulations of the distributor and the runner were performed, in order to simulate more accurately the pressure fields on the blade and the velocity distribution at the outlet of the runner. Moreover, draft tube computations have been performed close to the design point and at higher loads. Then, a model fully homologous with the prototype was manufactured and tested at ALSTOM's laboratory in Grenoble (France). The model test results confirmed the predicted ones: the

  1. Feasibility study of 5MW superconducting wind turbine generator

    DEFF Research Database (Denmark)

    Abrahamsen, Asger Bech; Jensen, Bogi Bech; Seiler, E.

    2011-01-01

    The feasibility of installing a direct drive superconducting generator in the 5MW reference offshore wind turbine of the National Renewable Energy Laboratory (NREL) has been examined. The engineering current densities Je obtained in a series of race track coils have been combined with magnetization...... measurements to estimate the properties of suitable field coils for a synchronous generator, which is more light weight than the conventional used combination of a gear box and a fast rotating generator. An analytical model and finite element simulations have been used to estimate the active mass of generators...

  2. Experimental study of biogas combustion using a gas turbine configuration

    Energy Technology Data Exchange (ETDEWEB)

    Lafay, Y.; Taupin, B.; Martins, G.; Cabot, G.; Renou, B.; Boukhalfa, A. [CNRS UMR 6614, Universite et INSA de ROUEN, Site universitaire du Madrillet, Saint Etienne du Rouvray (France)

    2007-08-15

    The aim of the present work is to compare stability combustion domains, flame structures and dynamics between CH{sub 4}/air flames and a biogas/air flames (issued from waste methanisation) in a lean gas turbine premixed combustion conditions. Velocity profiles are obtained by Laser Doppler Anemometry measurements. CH* chemiluminescence measurements and temporal acquisition of chamber pressure are performed in order to describe flame structure and instabilities. Changes in flame structure and dynamics when fuel composition is varying are found to strongly depend on laminar flame speed. No clear correlation between the unstable flame and the reaction zone penetration in the corner recirculation can be found. (orig.)

  3. Estimating the wake deflection downstream of a wind turbine in different atmospheric stabilities: an LES study

    Directory of Open Access Journals (Sweden)

    L. Vollmer

    2016-09-01

    Full Text Available An intentional yaw misalignment of wind turbines is currently discussed as one possibility to increase the overall energy yield of wind farms. The idea behind this control is to decrease wake losses of downstream turbines by altering the wake trajectory of the controlled upwind turbines. For an application of such an operational control, precise knowledge about the inflow wind conditions, the magnitude of wake deflection by a yawed turbine and the propagation of the wake is crucial. The dependency of the wake deflection on the ambient wind conditions as well as the uncertainty of its trajectory are not sufficiently covered in current wind farm control models. In this study we analyze multiple sources that contribute to the uncertainty of the estimation of the wake deflection downstream of yawed wind turbines in different ambient wind conditions. We find that the wake shapes and the magnitude of deflection differ in the three evaluated atmospheric boundary layers of neutral, stable and unstable thermal stability. Uncertainty in the wake deflection estimation increases for smaller temporal averaging intervals. We also consider the choice of the method to define the wake center as a source of uncertainty as it modifies the result. The variance of the wake deflection estimation increases with decreasing atmospheric stability. Control of the wake position in a highly convective environment is therefore not recommended.

  4. A performance study on a direct drive hydro turbine for wave energy converter

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Young Do [Mokpo National University, Muan (Korea, Republic of); Kim, Chang Goo; Kim, You Taek; Lee, Young Ho [Korea Maritime University, Busan (Korea, Republic of); Song, Jung Il [Changwon National University, Changwon (Korea, Republic of)

    2010-11-15

    Clean and renewable energy technologies using ocean energy give us non-polluting alternatives to fossil-fueled power plants as a countermeasure against global warming and growing demand for electrical energy. Among the ocean energy resources, wave power takes a growing interest because of its enormous amount of potential energy in the world. Therefore, various types of wave power systems to capture the energy of ocean waves have been developed. However, a suitable turbine type is not yet normalized because of relatively low efficiency of the turbine systems. The purpose of this study is to investigate the performance of a newly developed direct drive hydro turbine (DDT), which will be built in a caisson for a wave power plant. Experiment and CFD analysis are conducted to clarify the turbine performance and internal flow characteristics. The results show that the DDT obtains fairly good turbine efficiency in cases with and without wave conditions. Most of the output power is generated at the runner passage of Stage 2. Relatively larger amount of the decreased tangential velocity at Stage 2 produces more angular momentum than that at Stage 1 and thus, the larger angular momentum at the Stage 2 makes a greater contribution to the generation of total output power in comparison with that at Stage 1. Large vortex existing in the upper-left region of the runner passage forms a large recirculation region in the runner passage, and the recirculating flow consumes the output power at Region 2

  5. WindPACT Turbine Rotor Design Study: June 2000--June 2002 (Revised)

    Energy Technology Data Exchange (ETDEWEB)

    Malcolm, D. J.; Hansen, A. C.

    2006-04-01

    This report presents the results of the turbine rotor study completed by Global Energy Concepts (GEC) as part of the U.S. Department of Energy's WindPACT (Wind Partnership for Advanced Component Technologies) project. The purpose of the WindPACT project is to identify technology improvements that will enable the cost of energy from wind turbines to fall to a target of 3.0 cents/kilowatt-hour in low wind speed sites. The study focused on different rotor configurations and the effect of scale on those rotors.

  6. Small-scale biomass CHP using gasa turbines: a scoping study

    International Nuclear Information System (INIS)

    James, D.W.; Landen, R.

    1996-01-01

    Various options for small-scale (up to 250 KWe) Combined Heat and Power (CHP) plants evaluated in this scoping study. Plants using small gas turbines, and able to use biomass fuels when available are included. Three detailed case studies of small-scale biomass CHP plants are compared to match specific technical options with customer requirements. The commercial development of such biomass-fired CHP units, using gas turbines, is shown to be economically viable depending on fuel costs and the continuation of existing financial incentives. (UK)

  7. Aeroelastic Stability of Suspension Bridges using CFD

    DEFF Research Database (Denmark)

    Stærdahl, Jesper Winther; Sørensen, Niels; Nielsen, Søren R.K.

    2007-01-01

    In recent years large span suspension bridges with very thin and slender profiles have been built without proportional increasing torsional and bending stiffness. As a consequence large deformations at the mid-span can occur with risk of aeroelastic instability and structural failure. Analysis of...

  8. Calibration and Validation of the Dynamic Wake Meandering Model for Implementation in an Aeroelastic Code

    DEFF Research Database (Denmark)

    Aagaard Madsen, Helge; Larsen, Gunner Chr.; Larsen, Torben J.

    2010-01-01

    in an aeroelastic model. Calibration and validation of the different parts of the model is carried out by comparisons with actuator disk and actuator line (ACL) computations as well as with inflow measurements on a full-scale 2 MW turbine. It is shown that the load generating part of the increased turbulence......As the major part of new wind turbines are installed in clusters or wind farms, there is a strong need for reliable and accurate tools for predicting the increased loadings due to wake operation and the associated reduced power production. The dynamic wake meandering (DWM) model has been developed...... on this background, and the basic physical mechanisms in the wake—i.e., the velocity deficit, the meandering of the deficit, and the added turbulence—are modeled as simply as possible in order to make fast computations. In the present paper, the DWM model is presented in a version suitable for full integration...

  9. Evaluation of annoyance from the wind turbine noise: A pilot study

    Directory of Open Access Journals (Sweden)

    Małgorzata Pawlaczyk-Łuszczyńska

    2014-07-01

    Full Text Available Objectives: The overall aim of this study was to evaluate the perception of and annoyance due to the noise from wind turbines in populated areas of Poland. Material and Methods: The study group comprised 156 subjects. All subjects were asked to fill in a questionnaire developed to enable evaluation of their living conditions, including prevalence of annoyance due to the noise from wind turbines and the self-assessment of physical health and well-being. In addition, current mental health status of the respondents was assessed using Goldberg General Health Questionnaire GHQ-12. For areas where the respondents lived, A-weighted sound pressure levels (SPLs were calculated as the sum of the contributions from the wind power plants in the specific area. Results: It has been shown that the wind turbine noise at the calculated A-weigh­ted SPL of 30-48 dB was noticed outdoors by 60.3% of the respondents. This noise was perceived as annoying outdoors by 33.3% of the respondents, while indoors by 20.5% of them. The odds ratio of being annoyed outdoors by the wind turbine noise increased along with increasing SPLs (OR = 2.1; 95% CI: 1.22-3.62. The subjects' attitude to wind turbines in general and sensitivity to landscape littering was found to have significant impact on the perceived annoyance. About 63% of variance in outdoors annoyance assessment might be explained by the noise level, general attitude to wind turbines and sensitivity to landscape littering. Conclusions: Before firm conclusions can be drawn further studies are needed, including a larger number of respondents with different living environments (i.e., dissimilar terrain, different urbanization and road traffic intensity.

  10. Evaluation of annoyance from the wind turbine noise: a pilot study.

    Science.gov (United States)

    Pawlaczyk-Łuszczyńska, Małgorzata; Dudarewicz, Adam; Zaborowski, Kamil; Zamojska-Daniszewska, Małgorzata; Waszkowska, Małgorzata

    2014-06-01

    The overall aim of this study was to evaluate the perception of and annoyance due to the noise from wind turbines in populated areas of Poland. The study group comprised 156 subjects. All subjects were asked to fill in a questionnaire developed to enable evaluation of their living conditions, including prevalence of annoyance due to the noise from wind turbines and the self-assessment of physical health and well-being. In addition, current mental health status of the respondents was assessed using Goldberg General Health Questionnaire GHQ-12. For areas where the respondents lived, A-weighted sound pressure levels (SPLs) were calculated as the sum of the contributions from the wind power plants in the specific area. It has been shown that the wind turbine noise at the calculated A-weighted SPL of 30-48 dB was noticed outdoors by 60.3% of the respondents. This noise was perceived as annoying outdoors by 33.3% of the respondents, while indoors by 20.5% of them. The odds ratio of being annoyed outdoors by the wind turbine noise increased along with increasing SPLs (OR = 2.1; 95% CI: 1.22-3.62). The subjects' attitude to wind turbines in general and sensitivity to landscape littering was found to have significant impact on the perceived annoyance. About 63% of variance in outdoors annoyance assessment might be explained by the noise level, general attitude to wind turbines and sensitivity to landscape littering. Before firm conclusions can be drawn further studies are needed, including a larger number of respondents with different living environments (i.e., dissimilar terrain, different urbanization and road traffic intensity).

  11. Conceptual design study of closed Brayton cycle gas turbines for fusion power generation

    International Nuclear Information System (INIS)

    Kuo, S.C.

    1976-01-01

    A conceptual design study is presented of closed Brayton cycle gas turbine power conversion systems suitable for integration with advanced-concept Tokamak fusion reactors (such as UWMAK-III) for efficient power generation without requiring cooling water supply for waste heat rejection. A baseline cycle configuration was selected and parametric performance analyses were made. Based on the results of the parametric analysis and trade-off and interface considerations, the reference design conditions for the baseline cycle were selected. Conceptual designs were made of the major helium gas turbine power system components including a 585-MWe single-shaft turbomachine, (three needed), regenerator, precooler, intercooler, and the piping system connecting them. Structural configuration and significant physical dimensions for major components are illustrated, and a brief discussion on major advantages, power control and crucial technologies for the helium gas turbine power system are presented

  12. Wind tunnel study of the wind turbine interaction with a boundary-layer flow: Upwind region, turbine performance, and wake region

    Science.gov (United States)

    Bastankhah, M.; Porté-Agel, F.

    2017-06-01

    Comprehensive wind tunnel experiments were carried out to study the interaction of a turbulent boundary layer with a wind turbine operating under different tip-speed ratios and yaw angles. Force and power measurements were performed to characterize the variation of thrust force (both magnitude and direction) and generated power of the wind turbine under different operating conditions. Moreover, flow measurements, collected using high-resolution particle-image velocimetry as well as hot-wire anemometry, were employed to systematically study the flow in the upwind, near-wake, and far-wake regions. These measurements provide new insights into the effect of turbine operating conditions on flow characteristics in these regions. For the upwind region, the results show a strong lateral asymmetry under yawed conditions. For the near-wake region, the evolution of tip and root vortices was studied with the use of both instantaneous and phase-averaged vorticity fields. The results suggest that the vortex breakdown position cannot be determined based on phase-averaged statistics, particularly for tip vortices under turbulent inflow conditions. Moreover, the measurements in the near-wake region indicate a complex velocity distribution with a speed-up region in the wake center, especially for higher tip-speed ratios. In order to elucidate the meandering tendency of far wakes, particular focus was placed on studying the characteristics of large turbulent structures in the boundary layer and their interaction with wind turbines. Although these structures are elongated in the streamwise direction, their cross sections are found to have a size comparable to the rotor area, so that they can be affected by the presence of the turbine. In addition, the study of spatial coherence in turbine wakes reveals that any statistics based on streamwise velocity fluctuations cannot provide reliable information about the size of large turbulent structures in turbine wakes due to the effect of wake

  13. Aeroelastic Dynamics Simulation of Two BaffleBased Connected Shells

    Directory of Open Access Journals (Sweden)

    G. A. Shcheglov

    2015-01-01

    Full Text Available The present work is an extention study of aeroelastic vibrations of thin-walled structures with a spatial subsonic flow. An original algorithm for solving complex conjugated aeroelasticity problem, allowing to carry out direct numerical simulation of structural oscillations in the spatial flow of an incompressible medium are developed and tested. On the basis of this simulation study of the spectrum comes the driving forces acting on the flow in a spatial component elastic structure mounted on an impenetrable screen.Currently, updating the mathematical models of unsteady loads that act on the spacepurpose elastic designs such as launch vehicles, service tower installed on the launch pad is a challenge. We consider two thin-walled cantilevered rotating shells connected by a system of elastic couplings, installed next to the impenetrable baffle so that the axes of rotation are perpendicular to the baffle. Dynamics of elastic system is investigated numerically, using the vortex element method with the spatial separated flow of an incompressible medium. A feature of the algorithm is the common commercial complex MSC Patran / Nastran which is used in preparing data to calculate the shell dynamics thereby allowing to consider very complex dynamic schemes.The work performs the first calculations of the model problem concerning the forced oscillations of two coupled cylindrical shells in the flow of an incompressible medium. Comparing the load spectra for the elastic and absolutely rigid structure has shown that the frequency spectra vary slightly. Further calculations are required in which it will be necessary to increase the duration of the calculations, sampling in construction of design scheme, and given the large number of vibration modes that require increasing computing power.Experience in calculating aeroelastic dynamics of complex elastic structures taking into account the screen proved to be successful as a whole, thereby allowing to turn to

  14. Research in aeroelasticity EFP-2007

    Energy Technology Data Exchange (ETDEWEB)

    Bak, C.

    2008-07-15

    This report contains results from the EFP2007 project 'Program for Research in Applied Aeroelasticity'. The main results from this project are: 1) The rotor aerodynamics were computed using different types of models with focus on the flow around the tip. The results showed similar trend for all models. 2) Comparison of 3D CFD computations with and without inflow shear showed that the integrated rotor thrust and power were largely identical in the two situations. 3) The influence of tower shadow with and without inflow shear showed significant differences compared to BEMcomputations, which gives cause for further investigation. 4) 3D CFD computations showed that the flow in the region of the nacelle anemometer measured the flow angle in the wake with errors up to as much as 7 deg. relative to the freestream flow angle. 5) As long as the flow over a blade remains attached there is little difference between 2-D and 3-D flow. However, at separation an increased lift is observed close to the rotational axis. 6) A correlation based transition model has been implemented in the incompressible EllipSys2D/3D Navier-Stokes solver. Computations on airfoils and rotors showed good agreement and distinct improvement in the drag predictions compared to using fully turbulent computations. 7) Comparing the method of Dynamic Wake Meandering (DWM) and IEC, the IECmodel seems conservative regarding fatigue and extreme loads for the yaw, driving torque and flapwise bending, whereas the loads on tower and blade torsion are non-conservative. 8) An experimental method for measuring transition point and energy spectra in airfoil boundary layers using microphones has been developed. 9) A robust and automatic method for detecting transition based on microphone measurement on airfoil surfaces has been developed. 10) Transition points and the corresponding instabilities have clearly been observed in airfoil boundary layers. 11) Predictions of the transition points on airfoils using

  15. Turbine related fish mortality

    International Nuclear Information System (INIS)

    Eicher, G.J.

    1993-01-01

    A literature review was conducted to assess the factors affecting turbine-related fish mortality. The mechanics of fish passage through a turbine is outlined, and various turbine related stresses are described, including pressure and shear effects, hydraulic head, turbine efficiency, and tailwater level. The methodologies used in determining the effects of fish passage are evaluated. The necessity of adequate controls in each test is noted. It is concluded that mortality is the result of several factors such as hardiness of study fish, fish size, concentrations of dissolved gases, and amounts of cavitation. Comparisons between Francis and Kaplan turbines indicate little difference in percent mortality. 27 refs., 5 figs

  16. A feasibility study of a new ATREX engine system of aft-turbine configuration

    Science.gov (United States)

    Isomura, Kousuke; Omi, Junsuke; Tanatsugu, Nobuhiro; Sato, Tetsuya; Kobayashi, Hiroaki

    2002-07-01

    A feasibility of ATREX (Air-Turbo-Ram Expander cycle) engine with conventional aft-turbine configuration has been studied to be developed in about 10 years, if the development project has started under enough resources. The novel tip-turbine of the original ATREX engine is replaced by a conventional aft-turbine, and the maximum turbine inlet temperature (TTT) is reduced to 1200K, to realize the engine by only using approved metal technologies of modern jet engines. The capability of the performance has been shown by parametric studies by changing components' design parameters. The study shows that the performance of the ATREX engine is not less than that of pre-cooled turbo jet. Some technical issues on developing the new ATREX engine have been addressed. The most important issue would come from the transient total temperature change due to the rapid acceleration from sea level static (SLS) condition (288K) to Mach 6 at 30km of altitude (1680K) in 6 minutes. The deformation due to transient thermal expansion has to be controlled. Especially, the change of the tip clearance and the clearance between rotors and stators are pointed out to be important design issues. The ATREX engine, which has shorter axial length and simpler rotor, has structural advantage over turbo jet.

  17. Grainex Mar-M 247 Turbine Disk Life Study for NASA's High Temperature High Speed Turbine Seal Test Facility

    Science.gov (United States)

    Delgado, Irebert R.

    2015-01-01

    An experimental and analytical fatigue life study was performed on the Grainex Mar-M 247 disk used in NASA s Turbine Seal Test Facility. To preclude fatigue cracks from growing to critical size in the NASA disk bolt holes due to cyclic loading at severe test conditions, a retirement-for-cause methodology was adopted to detect and monitor cracks within the bolt holes using eddy-current inspection. For the NASA disk material that was tested, the fatigue strain-life to crack initiation at a total strain of 0.5 percent, a minimum to maximum strain ratio of 0, and a bolt hole temperature of 649 C was calculated to be 665 cycles using -99.95 percent prediction intervals. The fatigue crack propagation life was calculated to be 367 cycles after implementing a safety factor of 2 on life. Thus, the NASA disk bolt hole total life or retirement life was determined to be 1032 cycles at a crack depth of 0.501 mm. An initial NASA disk bolt hole inspection at 665 cycles is suggested with 50 cycle inspection intervals thereafter to monitor fatigue crack growth.

  18. Turbinate surgery

    Science.gov (United States)

    Turbinectomy; Turbinoplasty; Turbinate reduction; Nasal airway surgery; Nasal obstruction - turbinate surgery ... There are several types of turbinate surgery: Turbinectomy: All or ... This can be done in several different ways, but sometimes a ...

  19. Computational Models for Nonlinear Aeroelastic Systems, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Clear Science Corp. and Duke University propose to develop and demonstrate new and efficient computational methods of modeling nonlinear aeroelastic systems. The...

  20. Variable Fidelity Aeroelastic Toolkit - Structural Model, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed innovation is a methodology to incorporate variable fidelity structural models into steady and unsteady aeroelastic and aeroservoelastic analyses in...

  1. Comparative Study on Impacts of Power Curve Model on Capacity Factor Estimation of Pitch-Regulated Turbines

    Directory of Open Access Journals (Sweden)

    MH Albadi

    2012-12-01

    Full Text Available The amount of energy produced by a turbine depends on the characteristics of both wind speed at the site under investigation and the turbine's power performance curve. The capacity factor (CF of a wind turbine is commonly used to estimate the turbine's average energy production. This paper investigates the effect of the accuracy of the power curve model on CF estimation. The study considers three CF models. The first CF model is based on a power curve model that underestimates the turbine output throughout the ascending segment of the power curve. To compensate for the aforementioned discrepancy, the Weibull parameters, c and k, which are used to describe wind profile, are calculated based on cubic mean wind speed (CMWS. The second CF model is based on the most accurate generic power curve model available in open literature. The third CF model is based on a new model of power performance curve which mimics the behavior of a typical pitch-regulated turbine curve. As the coefficients of this power curve model are based on a general estimation of the turbine output at different wind speeds, they can be further tuned to provide a more accurate fit with turbine data from a certain manufacturer.

  2. A large-eddy simulation study of wake propagation and power production in an array of tidal-current turbines.

    Science.gov (United States)

    Churchfield, Matthew J; Li, Ye; Moriarty, Patrick J

    2013-02-28

    This paper presents our initial work in performing large-eddy simulations of tidal turbine array flows. First, a horizontally periodic precursor simulation is performed to create turbulent flow data. Then those data are used as inflow into a tidal turbine array two rows deep and infinitely wide. The turbines are modelled using rotating actuator lines, and the finite-volume method is used to solve the governing equations. In studying the wakes created by the turbines, we observed that the vertical shear of the inflow combined with wake rotation causes lateral wake asymmetry. Also, various turbine configurations are simulated, and the total power production relative to isolated turbines is examined. We found that staggering consecutive rows of turbines in the simulated configurations allows the greatest efficiency using the least downstream row spacing. Counter-rotating consecutive downstream turbines in a non-staggered array shows a small benefit. This work has identified areas for improvement. For example, using a larger precursor domain would better capture elongated turbulent structures, and including salinity and temperature equations would account for density stratification and its effect on turbulence. Additionally, the wall shear stress modelling could be improved, and more array configurations could be examined.

  3. A Stereo PIV Study on the Wake Characteristics behind Dual-Rotor Wind Turbines

    Science.gov (United States)

    Hu, Hui; Wang, Zhenyu; Tian, Wei

    2015-11-01

    We report an experimental study to investigate the aeromechanics and wake characteristics of dual-rotor wind turbines (DRWTs) with co- and counter-rotating configurations, in comparison to those of a conventional single-rotor wind turbine (SRWT). The experiments were performed in a large-scale Aerodynamic/Atmospheric Boundary Layer (AABL) wind tunnel under neutral stability conditions. In addition to measuring the power outputs and dynamic wind loads acting on the SRWT and DRWT systems, a stereoscopic PIV was used for detailed wake flow field measurements (free-run and phase-locked) to quantify the characteristics of the turbulent turbine wake flow and to reveal visualize the evolution of the unsteady vortex structures in the wakes of DRWTs, in comparison with those behind a conventional SRWT systems. The detailed flow field measurements are correlated with the dynamic wind loads and power output measurements to elucidate underlying physics for higher total power yield and better durability of the wind turbines. The funding support from the Iowa Energy Center with Grant No. 14-008-OG and National Science Foundation (NSF) with Grant Numbers of CBET-1133751 and CBET-1438099 is gratefully acknowledged.

  4. Experimental study of redesigned draft tube of an Agnew microhydro turbine

    International Nuclear Information System (INIS)

    Mirzaei, Ammar; Shojaeefard, Mohammad Hassan; Babaei, Ali; Yassi, Yousef

    2015-01-01

    Highlights: • The component of a Agnew microhydro turbine was redesigned. • Surrogate-based optimization was applied to determine the shape of the component. • The modified component was tested according to ASME PTC 18. • The pressure recovery factor was improved as much as 20.3%. • The energy loss coefficient was dropped to as 4.0%. - Abstract: In this study, a surrogate-based optimization has been carried out for the components of an Agnew microhydro turbine. A neural network was constructed as the surrogate, while the Non-dominated Sorting Genetic Algorithm (NSGA-II) was used as the optimizer. The optimal design was found by numerical simulations, and the final design was manufactured and installed at the turbine outlet. The performance of the turbine components was then measured according to ASME performance test code. Comparison was carried out between the original draft tube and its modified under different operating conditions. The test results have confirmed that the pressure recovery factor of the new component increases by 20.3% and the loss coefficient diminishes by 4.0%, with regard to the original design under the best operating conditions.

  5. Experimental and Numerical Study of the Aerodynamic Characteristics of an Archimedes Spiral Wind Turbine Blade

    Directory of Open Access Journals (Sweden)

    Kyung Chun Kim

    2014-11-01

    Full Text Available A new type of horizontal axis wind turbine adopting the Archimedes spiral blade is introduced for urban-use. Based on the angular momentum conservation law, the design formula for the blade was derived using a variety of shape factors. The aerodynamic characteristics and performance of the designed Archimedes wind turbine were examined using computational fluid dynamics (CFD simulations. The CFD simulations showed that the new type of wind turbine produced a power coefficient (Cp of approximately 0.25, which is relatively high compared to other types of urban-usage wind turbines. To validate the CFD results, experimental studies were carried out using a scaled-down model. The instantaneous velocity fields were measured using the two-dimensional particle image velocimetry (PIV method in the near field of the blade. The PIV measurements revealed the presence of dominant vortical structures downstream the hub and near the blade tip. The interaction between the wake flow at the rotor downstream and the induced velocity due to the tip vortices were strongly affected by the wind speed and resulting rotational speed of the blade. The mean velocity profiles were compared with those predicted by the steady state and unsteady state CFD simulations. The unsteady CFD simulation agreed better with those of the PIV experiments than the steady state CFD simulations.

  6. WindPACT Turbine Design Scaling Studies: Technical Area 4 -- Balance-of-Station Cost

    Energy Technology Data Exchange (ETDEWEB)

    Shafer, D. A.; Strawmyer, K. R.; Conley, R. M.; Guidinger J. H.; Wilkie, D. C.; Zellman, T. F.

    2001-07-24

    DOE's Wind Partnerships for Advanced Component Technologies (WindPACT) program explores the most advanced wind-generating technologies for improving reliability and decreasing energy costs. The first step in the WindPact program is a scaling study to bound the optimum sizes for wind turbines, to define size limits for certain technologies, and to scale new technologies. The program is divided into four projects: Composite Blades for 80-120-meter Rotors; Turbine, Rotor, and Blade Logistics; Self-Erecting Tower and Nacelle Feasibility; and Balance-of-Station Cost. This report discusses balance-of-station costs, which includes the electrical power collector system, wind turbine foundations, communications and controls, meteorological equipment, access roadways, crane pads, and the maintenance building. The report is based on a conceptual 50-megawatt (MW) wind farm site near Mission, South Dakota. Cost comparisons are provided for four sizes of wind turbines: 750 kilowatt (kW), 2.5 MW, 5.0 MW, and 10.0 MW.

  7. WindPACT Turbine Design Scaling Studies: Technical Area 4 - Balance-of-Station Cost; ANNUAL

    International Nuclear Information System (INIS)

    Shafer, D. A.; Strawmyer, K. R.; Conley, R. M.; Guidinger J. H.; Wilkie, D. C.; Zellman, T. F.

    2001-01-01

    DOE's Wind Partnerships for Advanced Component Technologies (WindPACT) program explores the most advanced wind-generating technologies for improving reliability and decreasing energy costs. The first step in the WindPact program is a scaling study to bound the optimum sizes for wind turbines, to define size limits for certain technologies, and to scale new technologies. The program is divided into four projects: Composite Blades for 80-120-meter Rotors; Turbine, Rotor, and Blade Logistics; Self-Erecting Tower and Nacelle Feasibility; and Balance-of-Station Cost. This report discusses balance-of-station costs, which includes the electrical power collector system, wind turbine foundations, communications and controls, meteorological equipment, access roadways, crane pads, and the maintenance building. The report is based on a conceptual 50-megawatt (MW) wind farm site near Mission, South Dakota. Cost comparisons are provided for four sizes of wind turbines: 750 kilowatt (kW), 2.5 MW, 5.0 MW, and 10.0 MW

  8. Study of the Acoustic Effects of Hydrokinetic Tidal Turbines in Admiralty Inlet, Puget Sound

    Energy Technology Data Exchange (ETDEWEB)

    Brian Polagye; Jim Thomson; Chris Bassett; Jason Wood; Dom Tollit; Robert Cavagnaro; Andrea Copping

    2012-03-30

    Hydrokinetic turbines will be a source of noise in the marine environment - both during operation and during installation/removal. High intensity sound can cause injury or behavioral changes in marine mammals and may also affect fish and invertebrates. These noise effects are, however, highly dependent on the individual marine animals; the intensity, frequency, and duration of the sound; and context in which the sound is received. In other words, production of sound is a necessary, but not sufficient, condition for an environmental impact. At a workshop on the environmental effects of tidal energy development, experts identified sound produced by turbines as an area of potentially significant impact, but also high uncertainty. The overall objectives of this project are to improve our understanding of the potential acoustic effects of tidal turbines by: (1) Characterizing sources of existing underwater noise; (2) Assessing the effectiveness of monitoring technologies to characterize underwater noise and marine mammal responsiveness to noise; (3) Evaluating the sound profile of an operating tidal turbine; and (4) Studying the effect of turbine sound on surrogate species in a laboratory environment. This study focuses on a specific case study for tidal energy development in Admiralty Inlet, Puget Sound, Washington (USA), but the methodologies and results are applicable to other turbine technologies and geographic locations. The project succeeded in achieving the above objectives and, in doing so, substantially contributed to the body of knowledge around the acoustic effects of tidal energy development in several ways: (1) Through collection of data from Admiralty Inlet, established the sources of sound generated by strong currents (mobilizations of sediment and gravel) and determined that low-frequency sound recorded during periods of strong currents is non-propagating pseudo-sound. This helped to advance the debate within the marine and hydrokinetics acoustic

  9. Development of an aeroelastic vibration power harvester

    Science.gov (United States)

    Bryant, Matthew; Garcia, Ephrahim

    2009-03-01

    Aeroelastic vibration of structures represents a novel energy harvesting opportunity that may offer significant advantages over traditional wind power devices in many applications. Such a system could complement existing alternative energy sources by allowing for distributed power generation and placement in urban areas. The device configuration of a simple two degree aeroelastic system suitable for piezoelectric power harvesting is presented. The mechanical, electromechanical, and aerodynamic equations of motion governing the dynamics and electrical output of the system as a function of incident wind speed are derived. The response and current output of one design for a bench top scale harvester are simulated and presented. Finally, a strategy for expanding the operating envelope of the power harvester is proposed and discussed.

  10. Aeroelastic Analysis of Modern Complex Wings

    Science.gov (United States)

    Kapania, Rakesh K.; Bhardwaj, Manoj K.; Reichenbach, Eric; Guruswamy, Guru P.

    1996-01-01

    A process is presented by which aeroelastic analysis is performed by using an advanced computational fluid dynamics (CFD) code coupled with an advanced computational structural dynamics (CSD) code. The process is demonstrated on an F/A-18 Stabilator using NASTD (an in-house McDonnell Douglas Aerospace East CFD code) coupled with NASTRAN. The process is also demonstrated on an aeroelastic research wing (ARW-2) using ENSAERO (an in-house NASA Ames Research Center CFD code) coupled with a finite element wing-box structures code. Good results have been obtained for the F/A-18 Stabilator while results for the ARW-2 supercritical wing are still being obtained.

  11. Development of Variable Camber Continuous Trailing Edge Flap for Performance Adaptive Aeroelastic Wing

    Science.gov (United States)

    Nguyen, Nhan; Kaul, Upender; Lebofsky, Sonia; Ting, Eric; Chaparro, Daniel; Urnes, James

    2015-01-01

    This paper summarizes the recent development of an adaptive aeroelastic wing shaping control technology called variable camber continuous trailing edge flap (VCCTEF). As wing flexibility increases, aeroelastic interactions with aerodynamic forces and moments become an increasingly important consideration in aircraft design and aerodynamic performance. Furthermore, aeroelastic interactions with flight dynamics can result in issues with vehicle stability and control. The initial VCCTEF concept was developed in 2010 by NASA under a NASA Innovation Fund study entitled "Elastically Shaped Future Air Vehicle Concept," which showed that highly flexible wing aerodynamic surfaces can be elastically shaped in-flight by active control of wing twist and bending deflection in order to optimize the spanwise lift distribution for drag reduction. A collaboration between NASA and Boeing Research & Technology was subsequently funded by NASA from 2012 to 2014 to further develop the VCCTEF concept. This paper summarizes some of the key research areas conducted by NASA during the collaboration with Boeing Research and Technology. These research areas include VCCTEF design concepts, aerodynamic analysis of VCCTEF camber shapes, aerodynamic optimization of lift distribution for drag minimization, wind tunnel test results for cruise and high-lift configurations, flutter analysis and suppression control of flexible wing aircraft, and multi-objective flight control for adaptive aeroelastic wing shaping control.

  12. Adaptive neural control of aeroelastic response

    Science.gov (United States)

    Lichtenwalner, Peter F.; Little, Gerald R.; Scott, Robert C.

    1996-05-01

    The Adaptive Neural Control of Aeroelastic Response (ANCAR) program is a joint research and development effort conducted by McDonnell Douglas Aerospace (MDA) and the National Aeronautics and Space Administration, Langley Research Center (NASA LaRC) under a Memorandum of Agreement (MOA). The purpose of the MOA is to cooperatively develop the smart structure technologies necessary for alleviating undesirable vibration and aeroelastic response associated with highly flexible structures. Adaptive control can reduce aeroelastic response associated with buffet and atmospheric turbulence, it can increase flutter margins, and it may be able to reduce response associated with nonlinear phenomenon like limit cycle oscillations. By reducing vibration levels and loads, aircraft structures can have lower acquisition cost, reduced maintenance, and extended lifetimes. Phase I of the ANCAR program involved development and demonstration of a neural network-based semi-adaptive flutter suppression system which used a neural network for scheduling control laws as a function of Mach number and dynamic pressure. This controller was tested along with a robust fixed-gain control law in NASA's Transonic Dynamics Tunnel (TDT) utilizing the Benchmark Active Controls Testing (BACT) wing. During Phase II, a fully adaptive on-line learning neural network control system has been developed for flutter suppression which will be tested in 1996. This paper presents the results of Phase I testing as well as the development progress of Phase II.

  13. A study on reduced chemical mechanisms of ammonia/methane combustion under gas turbine conditions

    OpenAIRE

    Xiao, Hua; Howard, Michael; Valera Medina, Agustin; Dooley, Stephen; Bowen, Philip John

    2016-01-01

    As an alternative fuel and hydrogen carrier, ammonia is believed to have good potential for future power generation. To explore the feasibility of co-firing ammonia with methane, studies involving robust numerical analyses with detailed chemistry are required to progress towards industrial implementation. Therefore, the objective of this study is to determine a reduced mechanism for simulation studies of ammonia/methane combustion in practical gas turbine combustor conditions. Firstly, five d...

  14. Hybrid vortex simulations of wind turbines using a three-dimensional viscous-inviscid panel method

    DEFF Research Database (Denmark)

    Ramos García, Néstor; Hejlesen, Mads Mølholm; Sørensen, Jens Nørkær

    2017-01-01

    of the influence of the time-integration scheme used forevolving the wake in time, aeroelastic simulations of the National Renewable Energy Laboratory 5 MW wind turbine andan analysis of the central processing unit time showing the gains of using the hybrid filament-mesh method....

  15. Beyond Classical Upscaling : Integrated Aeroservoelastic Design and Optimization of Large Offshore Wind Turbines

    NARCIS (Netherlands)

    Ashuri, T.

    2012-01-01

    Issues related to environmental concern and fossil fuel exhaustion has made wind energy the most widely accepted renewable energy resource. However, there are still several challenges to be solved such as the integrated design of wind turbines, aeroelastic response and stability prediction, grid

  16. HAWCStab2 with super element foundations: A new tool for frequency analysis of offshore wind turbines

    DEFF Research Database (Denmark)

    Henriksen, Lars Christian; Hansen, Anders Melchior; Kragh, Knud Abildgaard

    2013-01-01

    HAWCStab2 is a linear frequency domain aero-elastic tool, developed by DTU Wind Energy, suitable for frequency and stability analysis of horizontal axis 3 bladed wind turbines [1]. This tool has now been extended to also handle complex offshore foundation types, such as jacket structures...

  17. Load attenuating passively adaptive wind turbine blade

    Science.gov (United States)

    Veers, Paul S.; Lobitz, Donald W.

    2003-01-07

    A method and apparatus for improving wind turbine performance by alleviating loads and controlling the rotor. The invention employs the use of a passively adaptive blade that senses the wind velocity or rotational speed, and accordingly modifies its aerodynamic configuration. The invention exploits the load mitigation prospects of a blade that twists toward feather as it bends. The invention includes passively adaptive wind turbine rotors or blades with currently preferred power control features. The apparatus is a composite fiber horizontal axis wind-turbine blade, in which a substantial majority of fibers in the blade skin are inclined at angles of between 15 and 30 degrees to the axis of the blade, to produces passive adaptive aeroelastic tailoring (bend-twist coupling) to alleviate loading without unduly jeopardizing performance.

  18. Wind Turbine and Wind Power Plant Modelling Aspects for Power System Stability Studies

    DEFF Research Database (Denmark)

    Altin, Müfit; Hansen, Anca Daniela; Göksu, Ömer

    2014-01-01

    is not reasonable regarding the focus of the study. Therefore the power system operators should be aware of the modelling aspects of the wind power considering the related stability study and implement the required model in the appropriate power system toolbox. In this paper, the modelling aspects of wind turbines...... and wind power plants are reviewed for power system stability studies. Important remarks of the models are presented by means of simulations to emphasize the impact of these modelling details on the power system.......Large amount of wind power installations introduce modeling challenges for power system operators at both the planning and operational stages of power systems. Depending on the scope of the study, the modeling details of the wind turbine or the wind power plant are required to be different. A wind...

  19. Alternative Design Study Report: WindPACT Advanced Wind Turbine Drive Train Designs Study; November 1, 2000 -- February 28, 2002

    Energy Technology Data Exchange (ETDEWEB)

    Poore, R.; Lettenmaier, T.

    2003-08-01

    This report presents the Phase I results of the National Renewable Energy Laboratory's (NREL's) WindPACT (Wind Partnership for Advanced Component Technologies) Advanced Wind Turbine Drive Train Designs Study. Global Energy Concepts, LLC performed this work under a subcontract with NREL. The purpose of the WindPACT project is to identify technology improvements that will enable the cost of energy (COE) from wind turbines to be reduced. Other parts of the WindPACT project have examined blade and logistics scaling, balance-of-station costs, and rotor design. This study was designed to investigate innovative drive train designs.

  20. Electric Generators Fitted to Wind Turbine Systems: An Up-to-Date Comparative Study

    OpenAIRE

    Lebsir, A; Bentounsi, A; Benbouzid, Mohamed; Mangel, H

    2015-01-01

    International audience; This paper describes a comparative study allowing the selection of the most appropriate innovative structures for electrical machines for a wind turbine system. This study is based on an exhaustive review of the state of the art and on an effective comparison of the performances of the three main conventional electric generator in wind energy application system that are the Doubly-Fed Induction Generator (DFIG), the Squirrel-Cage Induction Generator (SCIG), the Permane...

  1. An Experimental Study of Lightning Overvoltages in Wind Turbine Generation Systems Using a Reduced-Size Model

    Science.gov (United States)

    Yamamoto, Kazuo; Noda, Taku; Yokoyama, Shigeru; Ametani, Akihiro

    Wind turbine generation systems are built at locations where few tall structures are found nearby so as to obtain good wind conditions, and thus, they are often struck by lightning. To promote wind power generation, lightning-protection methodologies for such wind turbine generation systems have to be established. This paper presents the result of an experimental study of lightning overvoltages in wind turbine generation systems using a reduced-size wind turbine model. Overvoltages observed at wavefronts of lightning surges are focused on in this study. In the experiments, lightning strokes to one of the blades and to the nacelle were considered, and voltages and currents at various positions of the wind turbine model were measured. The following points have been deduced from the results: (i) The voltage rise due to the tower footing resistance can cause a significant voltage difference between the tower foot and an incoming conductor led from a distant point. Also, a voltage difference between the bottom of down conductors installed inside the tower and an incoming conductor can be of significance. (ii) The lightning current flowing through the tower body induces voltages in main and control circuits which form loops, and the induced voltages can cause overvoltages and malfunctions. (iii) Traveling-wave phenomena in a wind turbine generation system for a lightning strike to the tip of a blade and to the nacelle have been made clear from the measured waveforms. This information can be used for developing an EMTP simulation model of wind turbine generation systems.

  2. Seismic analysis of wind turbines in the time domain

    Energy Technology Data Exchange (ETDEWEB)

    Witcher, D. [Garrad Hassan and Partners Ltd., Bristol (United Kingdom)

    2004-07-01

    The analysis of wind turbine loading associated with earthquakes is clearly important when designing for and assessing the feasibility of wind farms in seismically active regions. The approach taken for such analysis is generally based on codified methods which have been developed for the assessment of seismic loads acting on buildings. These methods are not able to deal properly with the aeroelastic interaction of the dynamic motion of the wind turbine structure with either the wind loading acting on the rotor blades or the response of the turbine controller. This article presents an alternative approach, which is to undertake the calculation in the time domain. In this case a full aeroelastic model of the wind turbine subject to turbulent wind loading is further excited by ground motion corresponding to the earthquake. This capability has been introduced to the GH Bladed wind turbine simulation package. The software can be used to compute the combined wind and earthquake loading of a wind turbine given a definition of the external conditions for an appropriate series of load cases. This article discusses the method and presents example results. (Author)

  3. Seismic analysis of wind turbines in the time domain

    Energy Technology Data Exchange (ETDEWEB)

    Witcher, D. [Garrad Hassan and Partners, Bristol (United Kingdom)

    2005-07-01

    The analysis of wind turbine loading associated with earthquakes is clearly important when designing for and assessing the feasibility of wind farms in seismically active regions. The approach taken for such analysis is generally based on codified methods which have been developed for the assessment of seismic loads acting on buildings. These methods are not able to deal properly with the aeroelastic interaction of the dynamic motion of the wind turbine structure with either the wind loading acting on the rotor blades or the response of the turbine controller. This article presents an alternative approach, which is to undertake the calculation in the time domain. In this case a full aeroelastic model of the wind turbine subject to turbulent wind loading is further excited by ground motion corresponding to the earthquake. This capability has been introduced to the GH Bladed wind turbine simulation package. The software can be used to compute the combined wind and earthquake loading of a wind turbine given a definition of the external conditions for an appropriate series of load cases. This article discusses the method and presents example results. (author)

  4. Demonstration of the Ability of RCAS to Model Wind Turbines

    Energy Technology Data Exchange (ETDEWEB)

    Jonkman, J.; Cotrell, J.

    2003-08-01

    In recent years, the wind industry has sponsored the development, verification, and validation of comprehensive aeroelastic simulators, which are used for wind turbine design, certification, and research. Unfortunately, as wind turbines continue to grow in size and sometimes exhibit unconventional design characteristics, the existing codes do not always support the additional analysis features required for proper design. The development history, functionality, and advanced nature of RCAS (Rotorcraft Comprehensive Analysis System) make this code a sensible option. RCAS is an aeroelastic simulator developed over a 4-year cooperative effort amongst the U.S. Army's Aeroflightdynamics Directorate, Advanced Rotorcraft Technology (ART), Inc., and the helicopter industry. As its name suggests, RCAS was created for the rotorcraft industry but developed as a general purpose code for modeling the aerodynamic and structural response of any system with rotating and nonrotating subsystems (such as wind turbines). To demonstrate that RCAS can analyze wind turbines, models of a conventional, 1.5-MW, 3-bladed, upwind, horizontal axis wind turbine (HAWT) are created in RCAS and wind turbine analysis codes FAST (Fatigue, Aerodynamics, Structures, and Turbulence) and ADAMS (Automatic Dynamic Analysis of Mechanical Systems). Using these models, a side-by-side comparison of structural response predictions is performed under several test scenarios.

  5. Parameter estimation of an aeroelastic aircraft using neural networks

    Indian Academy of Sciences (India)

    https://www.ias.ac.in/article/fulltext/sadh/025/02/0181-0191. Keywords. Parameter estimation; modelling; aeroelastic aircraft; neural networks; system identification. Abstract. Application of neural networks to the problem of aerodynamic modelling and parameter estimation for aeroelastic aircraft is addressed. A neural model ...

  6. Design and Testing of Aeroelastically Tailored Wings Under Maneuver Loading

    NARCIS (Netherlands)

    Werter, N.P.M.; Sodja, J.; De Breuker, R.

    2016-01-01

    The goal of the present paper is to provide experimental validation data for the aeroelastic analysis of composite aeroelastically tailored wings with a closed-cell cross-sectional structure. Several rectangular wings with differ- ent skin thicknesses and composite layups are designed in order to

  7. Experimental Vision Studies of Flow and Structural Effects on Wind Turbines

    DEFF Research Database (Denmark)

    Najafi, Nadia

    In the present thesis, two modern vision technologies are developed and used to study wind turbines: 1- Stereo vision to study vibrations and dynamics of the Vertical Axes Wind Turbine (VAWT) via operational modal analysis (OMA) 2- Background-oriented Schlieren (BOS) method to study the tip...... measurement sets in OMA. Therefore, the first four natural frequencies are identified and agreed fairly with classical modal analysis (EMA) and finite element simulation (FEM). The second experiment is conducted on a VAWT rotor in the wind tunnel in a more controlled and designed condition...... obtained with OMA are validated with the simulation and EMA, and then, the differences are explained with the aerodynamic effect and boundary conditions. The other frequencies obtained by OMA are interpreted via vortex shedding phenomena and guy wire effects. In the fifth chapter, the uncertainty...

  8. Contribution at the study of by pass turbine lines of thermal or nuclear power plants

    International Nuclear Information System (INIS)

    Bentolila, C.

    1988-07-01

    The objective of this thesis is to understand and to interpret the complex structure of transitories flows met by rapid expansion of dry steam in turbine bypass. The first chapter gives the general condition of the turbine bypass, the role and the operating conditions. Each part, taken in account separately, is described and permits to situate their particularities. The second chapter concerns the instationary one dimensional study of the flow in order to situate quantitatively the pressure, the temperature and the Mach number. The third chapter concerns the tests realized on mockup in order to put in clearness some large parameters such as diaphragm structure, lenghts and expansion chamber shapes. The last chapter concerns a more elaborate study on one expansion stage in terms of enter diaphragm geometry, number of holes, cylindrical or rectangular shape. This study in two dimensional flows, has for objective to specify the flow structure of supersonic jet on flat wall [fr

  9. Data driven fault detection and isolation: a wind turbine scenario

    Directory of Open Access Journals (Sweden)

    Rubén Francisco Manrique Piramanrique

    2015-04-01

    Full Text Available One of the greatest drawbacks in wind energy generation is the high maintenance cost associated to mechanical faults. This problem becomes more evident in utility scale wind turbines, where the increased size and nominal capacity comes with additional problems associated with structural vibrations and aeroelastic effects in the blades. Due to the increased operation capability, it is imperative to detect system degradation and faults in an efficient manner, maintaining system integrity, reliability and reducing operation costs. This paper presents a comprehensive comparison of four different Fault Detection and Isolation (FDI filters based on “Data Driven” (DD techniques. In order to enhance FDI performance, a multi-level strategy is used where:  the first level detects the occurrence of any given fault (detection, while  the second identifies the source of the fault (isolation. Four different DD classification techniques (namely Support Vector Machines, Artificial Neural Networks, K Nearest Neighbors and Gaussian Mixture Models were studied and compared for each of the proposed classification levels. The best strategy at each level could be selected to build the final data driven FDI system. The performance of the proposed scheme is evaluated on a benchmark model of a commercial wind turbine

  10. The 15 kW sub e (nominal) solar thermal electric power conversion concept definition study: Steam Rankine turbine system

    Science.gov (United States)

    Bland, T. J.

    1979-01-01

    A study to define the performance and cost characteristics of a solar powered, steam Rankine turbine system located at the focal point of a solar concentrator is presented. A two stage re-entry turbine with reheat between stages, which has an efficiency of 27% at a turbine inlet temperature of 732 C was used. System efficiency was defined as 60 Hertz electrical output divided by absorbed thermal input in the working fluid. Mass production costs were found to be approximately 364 dollars/KW.

  11. Study of PWR reactor efficiency as a function of turbine steam extractions

    International Nuclear Information System (INIS)

    Rocha, Janine Gandolpho da; Alvim, Antonio Carlos Marques; Martinez, Aquilino Senra

    2002-01-01

    The objective of this work is to optimize the extractions of the low-pressure turbine of a PWR nuclear reactor, in order to obtain the best thermodynamic cycle efficiency. We have analyzed typical data of a 1300 MW PWR reactor, operating at 25%, 50%, 75% and 100% capacities, respectively. The first stage of this study consists of generating a mathematical model capable of describing the reactor behavior and efficiency at any power level. The second stage of this study consists of to combine the generated mathematical model in an optimization computer program that optimize the extractions flow of the low-pressure turbine until it finds the optimal system efficiency. This work does not alter the nuclear facility project in any way. (author)

  12. Basic controller tuning for large offshore wind turbines

    Directory of Open Access Journals (Sweden)

    K. O. Merz

    2016-09-01

    Full Text Available When a wind turbine operates above the rated wind speed, the blade pitch may be governed by a basic single-input–single-output PI controller, with the shaft speed as input. The performance of the wind turbine depends upon the tuning of the gains and filters of this controller. Rules of thumb, based upon pole placement, with a rigid model of the rotor, are inadequate for tuning the controller of large, flexible, offshore wind turbines. It is shown that the appropriate controller tuning is highly dependent upon the characteristics of the aeroelastic model: no single reference controller can be defined for use with all models. As an example, the ubiquitous National Renewable Energy Laboratory (NREL 5 MW wind turbine controller is unstable when paired with a fully flexible aeroelastic model. A methodical search is conducted, in order to find models with a minimum number of degrees of freedom, which can be used to tune the controller for a fully flexible aeroelastic model; this can be accomplished with a model containing 16–20 states. Transient aerodynamic effects, representing rotor-average properties, account for five of these states. A simple method is proposed to reduce the full transient aerodynamic model, and the associated turbulent wind spectra, to the rotor average. Ocean waves are also an important source of loading; it is recommended that the shaft speed signal be filtered such that wave-driven tower side-to-side vibrations do not appear in the PI controller output. An updated tuning for the NREL 5 MW controller is developed using a Pareto front technique. This fixes the instability and gives good performance with fully flexible aeroelastic models.

  13. Wind Turbines Wake Aerodynamics

    DEFF Research Database (Denmark)

    Vermeer, L.; Sørensen, Jens Nørkær; Crespo, A.

    2003-01-01

    The aerodynamics of horizontal axis wind turbine wakes is studied. The contents is directed towards the physics of power extraction by wind turbines and reviews both the near and the far wake region. For the near wake, the survey is restricted to uniform, steady and parallel flow conditions......, thereby excluding wind shear, wind speed and rotor setting changes and yawed conditions. The emphasis is put on measurements in controlled conditions.For the far wake, the survey focusses on both single turbines and wind farm effects, and the experimental and numerical work are reviewed; the main interest...... is to study how the far wake decays downstream, in order to estimate the effect produced in downstream turbines.The article is further restricted to horizontal axis wind turbines and excludes all other types of turbines....

  14. A study of silver behavior in Gas-turbine High Temperature Gas-cooled Reactor

    International Nuclear Information System (INIS)

    Sawa, Kazuhiro; Tanaka, Toshiyuki

    1995-11-01

    A Gas-turbine High Temperature Gas-cooled Reactor (GT-HTGR) is one of the promising reactor systems of future HTGRs. In the design of GT-HTGR, behavior of fission products, especially of silver, is considered to be important from the view point of maintenance of gas-turbine. A study of silver behavior in the GT-HTGR was carried out based on current knowledge. The purposes of this study were to determine an importance of the silver problem quantitatively, countermeasures to the problem and items of future research and development which will be needed. In this study, inventory, fractional release from fuel, plateout in the primary circuit and radiation dose were evaluated, respectively. Based on this study, it is predicted that gamma-ray from plateout silver in gas-turbine system contributes about a half of total radiation dose after reactor shutdown. In future, more detail data for silver release from fuel, plateout behavior, etc. using the High Temperature Engineering Test Reactor (HTTR), for example, will be needed to carry out reasonable design. (author)

  15. Design study of a 10 MW MgB2 superconductor direct drive wind turbine generator

    DEFF Research Database (Denmark)

    Abrahamsen, Asger Bech; Magnusson, Niklas; Liu, Dong

    2014-01-01

    A design study of a 10 MW direct drive wind turbine generator based on MgB2 superconducting wires is presented and the cost of the active materials of the generator is estimated to be between 226 €/kW and 84 €/kw, which is lower than the threshold values of 300 €/kW of the INNWIND.EU project. A n...

  16. Computational Study on the Effect of Shroud Shape on the Efficiency of the Gas Turbine Stage

    Science.gov (United States)

    Afanas'ev, I. V.; Granovskii, A. V.

    2018-03-01

    The last stages of powerful power gas turbines play an important role in the development of power and efficiency of the whole unit as well as in the distribution of the flow parameters behind the last stage, which determines the efficient operation of the exhaust diffusers. Therefore, much attention is paid to improving the efficiency of the last stages of gas turbines as well as the distribution of flow parameters. Since the long blades of the last stages of multistage high-power gas turbines could fall into the resonance frequency range in the course of operation, which results in the destruction of the blades, damping wires or damping bolts are used for turning out of resonance frequencies. However, these damping elements cause additional energy losses leading to a reduction in the efficiency of the stage. To minimize these losses, dampening shrouds are used instead of wires and bolts at the periphery of the working blades. However, because of the strength problems, designers have to use, instead of the most efficient full shrouds, partial shrouds that do not provide for significantly reducing the losses in the tip clearance between the blade and the turbine housing. In this paper, a computational study is performed concerning an effect that the design of the shroud of the turbine-working blade exerted on the flow structure in the vicinity of the shroud and on the efficiency of the stage as a whole. The analysis of the flow structure has shown that a significant part of the losses under using the shrouds is associated with the formation of vortex zones in the cavities on the turbine housing before the shrouds, between the ribs of the shrouds, and in the cavities at the outlet behind the shrouds. All the investigated variants of a partial shrouding are inferior in efficiency to the stages with shrouds that completely cover the tip section of the working blade. The stage with a unshrouded working blade was most efficient at the values of the relative tip clearance

  17. Aeroelastic tailoring and structural optimisation using an advanced dynamic aeroelastic framework

    NARCIS (Netherlands)

    Werter, N.P.M.; De Breuker, R.

    2015-01-01

    Driven by a need to improve the efficiency of aircraft and reduce the fuel consumption, composite materials are applied extensively in the design of aircraft. A dynamic aeroelastic framework for the conceptual design of a generic composite wing structure is presented. The wing is discretized in

  18. Feasibility study of a hybrid wind turbine system – Integration with compressed air energy storage

    International Nuclear Information System (INIS)

    Sun, Hao; Luo, Xing; Wang, Jihong

    2015-01-01

    Highlights: • A new hybrid wind turbine system is proposed and feasibility study if conducted. • A complete mathematical model is developed and implemented in a software environment. • Multi-mode control strategy is investigated to ensure the system work smoothly and efficiently. • A prototype for implementing the proposed mechanism is built and tested as proof of the concept. • The proposed system is proved to be technically feasible with energy efficiency around 50%. - Abstract: Wind has been recognized as one of major realistic clean energy sources for power generation to meet the continuously increased energy demand and to achieve the carbon emission reduction targets. However, the utilisation of wind energy encounters an inevitable challenge resulting from the nature of wind intermittency. To address this, the paper presents the recent research work at Warwick on the feasibility study of a new hybrid system by integrating a wind turbine with compressed air energy storage. A mechanical transmission mechanism is designed and implemented for power integration within the hybrid system. A scroll expander is adopted to serve as an “air-machinery energy converter”, which can transmit additional driving power generalized from the stored compressed air to the turbine shaft for smoothing the wind power fluctuation. A mathematical model for the complete hybrid process is developed and the control strategy is investigated for corresponding cooperative operations. A prototype test rig for implementing the proposed mechanism is built for proof of the concept. From the simulated and experimental studies, the energy conversion efficiency analysis is conducted while the system experiences different operation conditions and modes. It is proved that the proposed hybrid wind turbine system is feasible technically

  19. An experimental and numerical study of the atmospheric stability impact on wind turbine wakes

    DEFF Research Database (Denmark)

    Machefaux, Ewan; Larsen, Gunner Chr.; Koblitz, Tilman

    2016-01-01

    In this paper, the impact of atmospheric stability on a wind turbine wake is studied experimentally and numerically. The experimental approach is based on full-scale (nacelle based) pulsed lidar measurements of the wake flow field of a stall-regulated 500 kW turbine at the DTU Wind Energy, Risø...... campus test site. Wake measurements are averaged within a mean wind speed bin of 1 m s1 and classified according to atmospheric stability using three different metrics: the Obukhov length, the Bulk–Richardson number and the Froude number. Three test cases are subsequently defined covering various...... atmospheric conditions. Simulations are carried out using large eddy simulation and actuator disk rotor modeling. The turbulence properties of the incoming wind are adapted to the thermal stratification using a newly developed spectral tensor model that includes buoyancy effects. Discrepancies are discussed...

  20. Comparative study of energy conversion system dedicated to a small wind turbine

    International Nuclear Information System (INIS)

    Mirecki, A.

    2005-01-01

    This study presents a comparison of architectures and strategies of energy management dedicated to VAWT turbines such as Savonius. A Maximum Power Point Tracking must be implemented in order to optimize the energetic behavior. A torque or a speed control, or an indirect control of the DC bus current is possible. In the fact that the wind turbine characteristic is unknown, an operational research based on fuzzy logic is proposed. Aiming to minimize the cost of the static conversion structure, simple structures (diode bridge inverter, associated with DC-DC chopper) are analyzed and compared with a system based on a PWM Voltage Source Inverter. A test bench has been realized in the meantime as a system simulation. Comparisons of the provided energy are made for different wind speeds allowing to evaluate the performance of each structure and of the control strategies. (author)

  1. Simulation of a flexible wind turbine response to a grid fault

    DEFF Research Database (Denmark)

    Hansen, Anca Daniela; Cutululis, Nicolaos Antonio; Sørensen, Poul Ejnar

    2007-01-01

    The purpose of this work is to illustrate the impact of a grid fault on the mechanical loads of a wind turbine. Grid faults generate transients in the generator electromagnetic torque, which are propagated in the wind turbine, stressing its mechanical components. Grid faults are normally simulated...... in power system simulation tools applying simplified mechanical models of the drive train. This paper presents simulations of the wind turbine load response to grid faults with an advanced aeroelastic computer code (HAWC2). The core of this code is an advanced model for the flexible structure of the wind...... turbines, taking the flexibility of the tower, blades and other components of the wind turbines into account. The effect of a grid fault on the wind turbine flexible structure is assessed for a typical fixed speed wind turbine, equipped with an induction generator....

  2. Wind turbines and idiopathic symptoms

    DEFF Research Database (Denmark)

    Blanes-Vidal, Victoria; Schwartz, Joel

    2016-01-01

    Whether or not wind turbines pose a risk to human health is a matter of heated debate. Personal reactions to other environmental exposures occurring in the same settings as wind turbines may be responsible of the reported symptoms. However, these have not been accounted for in previous studies. We...... investigated whether there is an association between residential proximity to wind turbines and idiopathic symptoms, after controlling for personal reactions to other environmental co-exposures. We assessed wind turbine exposures in 454 residences as the distance to the closest wind turbine (Dw) and number...... of wind turbines

  3. Unsteady boundary layer development on a wind turbine blade: an experimental study of a surrogate problem

    Science.gov (United States)

    Cadel, Daniel R.; Zhang, Di; Lowe, K. Todd; Paterson, Eric G.

    2018-04-01

    Wind turbines with thick blade profiles experience turbulent, periodic approach flow, leading to unsteady blade loading and large torque fluctuations on the turbine drive shaft. Presented here is an experimental study of a surrogate problem representing some key aspects of the wind turbine unsteady fluid mechanics. This experiment has been designed through joint consideration by experiment and computation, with the ultimate goal of numerical model development for aerodynamics in unsteady and turbulent flows. A cylinder at diameter Reynolds number of 65,000 and Strouhal number of 0.184 is placed 10.67 diameters upstream of a NACA 63215b airfoil with chord Reynolds number of 170,000 and chord-reduced frequency of k=2π fc/2/V=1.5. Extensive flow field measurements using particle image velocimetry provide a number of insights about this flow, as well as data for model validation and development. Velocity contours on the airfoil suction side in the presence of the upstream cylinder indicate a redistribution of turbulent normal stresses from transverse to streamwise, consistent with rapid distortion theory predictions. A study of the boundary layer over the suction side of the airfoil reveals very low Reynolds number turbulent mean streamwise velocity profiles. The dominance of the high amplitude large eddy passages results in a phase lag in streamwise velocity as a function of distance from the wall. The results and accompanying description provide a new test case incorporating moderate-reduced frequency inflow for computational model validation and development.

  4. Feasibility study of ultra-low NOx Gas turbine combustor using the RML combustion concept

    Energy Technology Data Exchange (ETDEWEB)

    Van, Tien Giap; Hwang, Jeong Jae; Kim, Min Kuk; Ahn, Kook Young [Environment and Energy Research Division, Korea Institute of Machinery and Materials (KIMM), Daejeon (Korea, Republic of)

    2016-12-15

    A new combustion concept, the so called RML, was investigated to validate its application as a gas turbine combustor for combustor outlet temperatures over 1973 K. The feasibility study of the RML combustor was conducted with zero dimensional combustion calculations. The emission characteristics of RQL, LEAN, EGR and RML combustors were compared. The calculation results showed that the RQL combustor has lower NOx emissions than the LEAN at high outlet temperature. NOx emissions of the RML combustor at equivalence ratio of the rich chamber of 2.0 can be reduced by 30 % compared with the EGR combustor, and lower than the RQL combustor at a combustor outlet temperature over 1973 K. However, the CO emissions of the RML combustor were higher than those of the LEAN and EGR combustors. Also, the possibility of applying the RML combustor to gas turbines was discussed considering residence time, equivalence ratio of the rich chamber and recirculation rate. Although further research to design and realize the proposed RML combustor is needed, this study verified that the RML concept can be successfully used in a gas turbine combustor.

  5. Combined, nonlinear aerodynamic and structural method for the aeroelastic design of a three-dimensional wing in supersonic flow

    Science.gov (United States)

    Pittman, J. L.; Giles, G. L.

    1986-01-01

    An iterative procedure for the static aeroelastic design of a flexible wing at supersonic speeds has been developed. The procedure combines a nonlinear, full-potential solver (NCOREL) with an equivalent plate structural analysis method. The NCOREL method yields significantly improved aerodynamic estimates compared to linear theory. The equivalent plate structural analysis method demonstrates an order of magnitude reduction in computer memory and execution time compared to finite-element methods. A highly swept wing is analyzed at high lift using this aeroelastic procedure. The results indicate that the wing deforms favorably due to aerodynamic loading and, consequently, that the inviscid drag levels do not vary at the required lift coefficient although the angle of attack varies significantly. A sensitivity analysis of the type required for optimization studies was also performed with the aeroelastic design procedure.

  6. Experimental study of separator effect and shift angle on crossflow wind turbine performance

    Science.gov (United States)

    Fahrudin, Tjahjana, Dominicus Danardono Dwi Prija; Santoso, Budi

    2018-02-01

    This paper present experimental test results of separator and shift angle influence on Crossflow vertical axis wind turbine. Modification by using a separator and shift angle is expected to improve the thrust on the blade so as to improve the efficiency. The design of the wind turbine is tested at different wind speeds. There are 2 variations of crossflow turbine design which will be analyzed using an experimental test scheme that is, 3 stage crossflow and 2 stage crossflow with the shift angle. Maximum power coefficient obtained as Cpmax = 0.13 at wind speed 4.05 m/s for 1 separator and Cpmax = 0.12 for 12° shear angle of wind speed 4.05 m/s. In this study, power characteristics of the crossflow rotor with separator and shift angle have been tested. The experimental data was collected by variation of 2 separator and shift angle 0°, 6°, 12° and wind speed 3.01 - 4.85 m/s.

  7. Do Wind Turbines Affect Weather Conditions?: A Case Study in Indiana

    Directory of Open Access Journals (Sweden)

    Meghan F. Henschen

    2011-01-01

    Full Text Available Wind turbines are becoming increasingly widespread in the United States as the world looks for cleaner sources of energy. Scientists, policymakers, and citizens have strong opinions regarding the positive and negative effects of wind energy projects, and there is a great deal of misinformation about wind energy circulating on the Web and other media sources. The purpose of this study is to gain a better understanding of how the rotation of hundreds of turbines can influence local weather conditions within a wind farm and in the surrounding areas. This experiment measures temperature, atmospheric pressure, wind speed, wind direction, relative humidity, and evaporation with five weather instruments at Meadow Lake Wind Farm located in White, Jasper, and Benton Counties, Indiana, from November 4 through November 18, 2010. The data show that as wind passes throughout the wind farm, the air warms during the overnight and early morning hours and cools during daytime hours. Observed lower humidity rates and higher evaporation rates downwind also demonstrate that the air dries out as it travels through the wind farm. Further research over multiple seasons is necessary to examine the effects of warmer nighttime temperatures and drier conditions progressively downwind of the installation. Nevertheless, wind turbines did not negatively affect local weather patterns in our small-scale research and may actually prevent frost, which could have important positive implications for farmers by potentially prolonging the growing season.

  8. Research in Aeroelasticity EFP-2007-II

    DEFF Research Database (Denmark)

    shadow models implemented in the aeroelastic code HAWC2. • Using a streamlined tower reduces the tower shadow by 50% compared to a cylindrical tower. Similar reductions can be achieved using a four legged lattice tower. • The application of laminar/turbulent transition in CFD computations for airfoils...... the aerodynamic characteristics, but with reduced noise in the order of up to 3dB in total sound power level and up to 1dB with A-weighting. • 2D CFD simulations are performed to verify their capability in predicting multi element airfoil configurations. The present computations show good agreement with measured...

  9. Triboelectret-based aeroelastic flutter energy harvesters

    Science.gov (United States)

    Perez, Matthias; Boisseau, Sebastien; Geisler, Matthias; Despesse, Ghislain; Reboud, Jean Luc

    2016-11-01

    This paper highlights some experimental results on several electrostatic membranes tested in a wind tunnel between 0 and 20m.s-1 for airflow energy harvesting. The main idea is to use the aeroelastic behavior of thin flexible films to induce simultaneously the capacitance variations and the polarization required by the triboelectric/electrostatic conversion. This technology provides thin and flexible devices and avoids the issue of electrets discharge. Our prototypes (energy harvesting chain, we have used a wireless sensor with temperature and acceleration measures coupled to a low power transmission (Bluetooth Low Energy) with reception on a smartphone.

  10. Dynamic behavior of parked wind turbine at extreme wind speed

    DEFF Research Database (Denmark)

    Totsuka, Yoshitaka; Imamura, Hiroshi; Yde, Anders

    2016-01-01

    In wind turbine design process, a series of load analysis is generally performed to determine ultimate and fatigue loads under various design load cases (DLCs) which is specified in IEC 61400. These design load scenario covers not only normal operating condition but also startup, shutdown, parked...... of standstill and idling is analyzed by time domain simulations using two different coupled aero-hydro-servo-elastic codes. Trend in modern wind turbines is development of bigger, lighter and more flexible rotors where vibration issues may cause aero-elastic instabilities which have a serious impact...

  11. Exergoeconomic assessment and parametric study of a Gas Turbine-Modular Helium Reactor combined with two Organic Rankine Cycles

    International Nuclear Information System (INIS)

    Mohammadkhani, F.; Shokati, N.; Mahmoudi, S.M.S.; Yari, M.; Rosen, M.A.

    2014-01-01

    An exergoeconomic analysis is reported for a combined system with a net electrical output of 299 MW in which waste heat from a Gas Turbine-Modular Helium Reactor (GT-MHR) is utilized by two Organic Rankine Cycles (ORCs). A parametric study is also done to reveal the effects on the exergoeconomic performance of the combined system of such significant parameters as compressor pressure ratio, turbine inlet temperature, temperatures of evaporators, pinch point temperature difference in the evaporators and degree of superheat at the ORC (Organic Rankine Cycle) turbines inlet. Finally the combined cycle performance is optimized from the viewpoint of exergoeconomics. The results show that the precooler, the intercooler and the ORC condensers exhibit the worst exergoeconomic performance. For the overall system, the exergoeconomic factor, the capital cost rate and the exergy destruction cost rate are determined to be 37.95%, 6876 $/h and 11,242 $/h, respectively. Also, it is observed that the unit cost of electricity produced by the GT-MHR turbine increases with increasing GT-MHR turbine inlet temperature but decreases as the other above mentioned parameters increase. - Highlights: • An exergoeconomic analysis is performed for the GT-MHR/ORC (Organic Rankine Cycle) combined cycle. • The effects of decision parameters on the exergoeconomic performance are studied. • The highest exergy destructions occur in the precooler, intercooler and condenser. • Superheating the working fluid at the ORC turbine inlet is not necessary. • Thermodynamic and exergoeconomic optimal conditions differ from each other

  12. Dynamics and control of hypersonic aeropropulsive/aeroelastic vehicles

    Science.gov (United States)

    Schmidt, David K.

    1992-01-01

    The guidance and control of hypersonic vehicles is examined by studying the airframe/engine/structural-dynamic interactions of a generic vehicle with scramjet propulsion. The pitch-attitude dynamics are described for the vehicle configuration that can sustain hypersonic flight at near-orbital altitudes. These aerospacecraft have strong airframe/engine/elastic coupling in attitude dynamics and engine responses with static instability with respect to pitch. An integrated airframe-engine control system is presented for the control of the system's strong aeropropulsive/aeroelastic coupling. The control methodology utilizes feedback of measured/synthesized values of angle of attack, blended pitch rate, thrust, and combustor-inlet pressure. The multiinput/multioutput engine controller requires high-bandwidth actuation of the fuel-flow control and the effective diffuser ratio. The proposed control laws do not provide optimized performance in terms of pitch response suggesting that additional control crossfeeds and filtering is needed.

  13. An FMEA-Based Risk Assessment Approach for Wind Turbine Systems: A Comparative Study of Onshore and Offshore

    Directory of Open Access Journals (Sweden)

    Mahmood Shafiee

    2014-02-01

    Full Text Available Failure mode and effects analysis (FMEA has been extensively used by wind turbine assembly manufacturers for analyzing, evaluating and prioritizing potential/known failure modes. However, several limitations are associated with its practical implementation in wind farms. First, the Risk-Priority-Number (RPN of a wind turbine system is not informative enough for wind farm managers from the perspective of criticality; second, there are variety of wind turbines with different structures and hence, it is not correct to compare the RPN values of different wind turbines with each other for prioritization purposes; and lastly, some important economical aspects such as power production losses, and the costs of logistics and transportation are not taken into account in the RPN value. In order to overcome these drawbacks, we develop a mathematical tool for risk and failure mode analysis of wind turbine systems (both onshore and offshore by integrating the aspects of traditional FMEA and some economic considerations. Then, a quantitative comparative study is carried out using the traditional and the proposed FMEA methodologies on two same type of onshore and offshore wind turbine systems. The results show that the both systems face many of the same risks, however there are some main differences worth considering.

  14. Studi Eksperimen Pengaruh Sudut Plat Pengganggu Di Depan Returning Blade Turbin Angin Tipe Savonius Terhadap Performa TurbinStudi Kasus Untuk Rasio Lebar Plat Pengganggu Terhadap Diameter Turbin (L/D = 1,4144”

    Directory of Open Access Journals (Sweden)

    Yoga Erry Priandika

    2017-01-01

    Full Text Available Energi Angin merupakan salah satu energi alternatif yang sangat menjanjikan jika dapat dimanfaatkan dengan baik. Pemanfaatan energi angin untuk diubah menjadi energi listrik dapat menggunakan turbin angin dan generator. Turbin angin tipe Savonius merupakan rotor angin dengan sumbu tegak (vertical yang dikembangkan oleh Singuard J. Savonius pada tahun 1920. Salah satu kelemahan yang dimiliki turbin Savonius yaitu efisiensi yang rendah. Torsi dan putaran yang dihasilkan oleh turbin Savonius disebabkan oleh adanya perbedaan gaya drag pada advancing blade dan returning blade. Salah satu cara untuk meningkatkan performa turbin Savonius  dapat dilakukan dengan pemberian plat pengganggu didepan returning blade. Untuk meningkatkan performa turbin Savonius dengan diameter D sebesar 60 mm dan tinggi h sebesar 80 mm, sebuah plat dengan tebal 3 mm dan lebar 84,9 mm digunakan sebagai pengganggu yang diletakkan didepan returning blade turbin. Pengganggu tersebut diletakkan dengan pada sudut 0o< ɑ < 90o. Penelitian ini dilakukan pada subsonic open circuit wind tunnel. Alat ini memiliki panjang 2980 mm, dengan test section 304 mm x 304 mm. Kecepatan free stream pada wind tunnel diatur sebesar 8,752 m/s, 10,94 m/s, 13,128 m/s, sesuai dengan Reynolds number Re = 6.0 x 104, 7.5 x 104, 9.0 x 104 (berdasarkan panjang karakteristik d = 2D-b, dimana b adalah lebar diameter overlap dari kedua sudu turbin, dan kecepatan free stream. Kecepatan aliran udara diukur menggunakan static pitot tube yang dihubungkan dengan inclined manometer. Putaran turbin Savonius diukur menggunakan tachometer. Torsi statis diukur menggunakan torsi meter digital dan daya output dihasilkan dari pengukuran tegangan dan arus listrik yang dihasilkan generator yang dihubungkan dengan poros turbin. Untuk Re = 60.000, penggunaan plat dengan lebar L/D = 1,4144 pada posisi ɑ = 40o sebagai pengganggu didepan turbin Savonius, terbukti paling efektif untuk meningkatkan performa turbin Savonius. Pada

  15. Numerical study of Wavy Blade Section for Wind Turbines

    DEFF Research Database (Denmark)

    Kobæk, C. M.; Hansen, Martin Otto Laver

    2016-01-01

    than a flipper having a smooth trailing edge and thus could be potentially beneficial when catching food. A thorough literature study of the Wavy Blade concept is made and followed by CFD computations of two wavy blade geometries and a comparison with their baseline S809 airfoil at conditions more...... that the results may very well depend on the actual airfoil geometry and perhaps also the Reynolds number, and future studies are necessary in order to illuminate this further....

  16. Transonic aeroelastic numerical simulation in aeronautical engineering

    International Nuclear Information System (INIS)

    Yang, G.

    2005-01-01

    An LU-SGS (lower-upper symmetric Gauss-Seidel) subiteration scheme is constructed for time-marching of the fluid equations. The HLLEW (Harten-Lax-van Leer-Einfeldt-Wada) scheme is used for the spatial discretization. The same subiteration formulation is applied directly to the structural equations of motion in generalized coordinates. Through subiteration between the fluid and structural equations, a fully implicit aeroelastic solver is obtained for the numerical simulation of fluid/structure interaction. To improve the ability for application to complex configurations, a multiblock grid is used for the flow field calculation and Transfinite Interpolation (TFI) is employed for the adaptive moving grid deformation. The infinite plate spline (IPS) and the principal of virtual work are utilized for the data transformation between the fluid and structure. The developed code was first validated through the comparison of experimental and computational results for the AGARD 445.6 standard aeroelastic wing. Then the flutter character of a tail wing with control surface was analyzed. Finally, flutter boundaries of a complex aircraft configuration were predicted. (author)

  17. LES investigation of infinite staggered wind-turbine arrays

    International Nuclear Information System (INIS)

    Yang, Xiaolei; Sotiropoulos, Fotis

    2014-01-01

    The layouts of turbines affect the turbine wake interactions and thus the wind farm performance. The wake interactions in infinite staggered wind-turbine arrays are investigated and compared with infinite aligned turbine arrays in this paper. From the numerical results we identify three types of wake behaviours, which are significantly different from wakes in aligned wind-turbine arrays. For the first type, each turbine wake interferes with the pair of staggered downstream turbine wakes and the aligned downstream turbine. For the second type, each turbine wake interacts with the first two downstream turbine wakes but does not show significant interference with the second aligned downstream turbine. For the third type, each turbine wake recovers immediately after passing through the gap of the first two downstream turbines and has little interaction with the second downstream turbine wakes The extracted power density and power efficiency are also studied and compared with aligned wind-turbine arrays

  18. Experimental and Numerical Vibrational Analysis of a Horizontal-Axis Micro-Wind Turbine

    Directory of Open Access Journals (Sweden)

    Francesco Castellani

    2018-02-01

    Full Text Available Micro-wind turbines are energy conversion technologies strongly affected by fatigue, as a result of their size and the variability of loads, induced by the unsteady wind conditions, and modulated by a very high rotational speed. This work is devoted to the experimental and numerical characterization of the aeroelastic behavior of a test-case horizontal-axis wind turbine (HAWT with a 2 m rotor diameter and a maximum power production of 3 kW. The experimental studies have been conducted at the wind tunnel of the University of Perugia and consisted of accelerometer measurements at the tower and the tail fin. The numerical setup was the Fatigue, Aerodynamics, Structures, and Turbulence (FAST code for aeroelastic simulations, which was fed as input with the same wind conditions employed in the wind tunnel tests. The experimental and numerical analyses were coupled with the perspective of establishing a reciprocal feedback, and this has been accomplished. On one hand, the numerical model is important for interpreting the measured spectrum of tower oscillations and, for example, inspires the detection of a mass unbalance at the blades. On the other hand, the measurements inspire the question of how to interpret the interaction between the blades and the tower. The experimental spectrum of tail fin vibrations indicates that secondary elements, in terms of weight, can also transmit to the tower, giving meaningful contributions to the vibration spectra. Therefore, an integrated numerical and experimental approach is not only valuable but is also unavoidable, to fully characterize the dynamics of small wind-energy conversion systems.

  19. DFIG turbine representation for small signal voltage control studies

    DEFF Research Database (Denmark)

    Garcia, Jorge Martinez; Kjær, Philip Carne; Teodorescu, Remus

    2010-01-01

    This paper addresses the representation of a wind power plant, based on wound rotor asynchronous generators, with a centralized voltage controller, by an equivalent transfer function, valid for small signal voltage control studies. This representation allows to investigate the influence of the ce...

  20. Effects of structure flexibility on horizontal axis wind turbine performances

    Science.gov (United States)

    Coiro, D. P.; Daniele, E.; Scherillo, F.

    2013-10-01

    This work illustrates the effects of flexibility of rotor blades and turbine tower on the performances of an horizontal axis wind turbine (HAWT) designed by our ADAG research group, by means of several example applied on a recent project for a active pitch controlled upwind 60 kW HAWT. The influence of structural flexibility for blade only, tower only and blade coupled with tower configuration is investigated using an aero-elastic computer-aided engineering (CAE) tool for horizontal axis wind turbines named FAST developed at National Renewable Energy Laboratory (NREL) of USA. For unsteady inflow conditions in front of the isolated HAWT the performances in rigid and flexible operation mode are computed and compared in order to illustrate the limitation included within a classical rigid body approach to wind turbine simulation.

  1. Flap controllers applied on the OffshoreWindChina (OWC) 5MW reference wind turbine for Chinese typhoon conditions

    DEFF Research Database (Denmark)

    Barlas, Athanasios

    The report describes the development of flap controllers applied on the OffshoreWindChina (OWC) 5MW reference wind turbine for Chinese typhoon conditions. Optimal flap controllers are designed and tuned based on linear aeroelastic models from HawcStab2. The controllers are evaluated in normal...

  2. Design Study of Fully Superconducting Wind Turbine Generators

    DEFF Research Database (Denmark)

    Song, Xiaowei (Andy); Mijatovic, Nenad; Jensen, Bogi Bech

    2015-01-01

    In this paper, two fully superconducting generators employing MgB2 armature winding, with YBCO and MgB2 field winding respectively, are presented and analyzed. The ac loss in armature winding is estimated, and a simple comparative study is carried out. The results show that both electromagnetic...... designs for fully superconducting generators are promising with respect to the power density. However, the cost of removing ac loss in armature winding is as high as $900 000. It is also noted that with the current price of YBCO tape, the generator employing MgB 2 field winding would have lower cost....

  3. Computational study of turbine blade cooling with various blowing ratios

    Directory of Open Access Journals (Sweden)

    Madhurima Dey

    2016-06-01

    Full Text Available This paper presents computational analysis of centerline film cooling effectiveness using Navier-Stokes equation solver. Film cooling effectiveness has been varied along the downstream of cooling holes. The computational model has been validated with benchmark experimental literature. Computational study compares film cooling effectiveness over various blowing ratios (M and various hole shapes. The k-ω shear stress transport model of FLUENT software has been used for the computational analysis. The hole geometry and blowing ratios have important effects on film cooling effectiveness. Computational results reveal that film cooling effectiveness increases with increase in blowing ratio whereas effectiveness decreases due to intermixing of coolant and mainstream flow and due to coolant jet lift off. The best results were obtained for fan-shaped hole with M=1.00. While for lower blowing ratio, coolant is unable to spread over a longer distance downstream of cooling holes.

  4. Modelling and control of variable speed wind turbines for power system studies

    DEFF Research Database (Denmark)

    Michalke, Gabriele; Hansen, Anca Daniela

    2010-01-01

    and implemented in the power system simulation tool DIgSILENT. Important issues like the fault ride-through and grid support capabilities of these wind turbine concepts are addressed. The paper reveals that advanced control of variable speed wind turbines can improve power system stability. Finally......, it will be shown in the paper that wind parks consisting of variable speed wind turbines can help nearby connected fixed speed wind turbines to ride-through grid faults. Copyright © 2009 John Wiley & Sons, Ltd.......Modern wind turbines are predominantly variable speed wind turbines with power electronic interface. Emphasis in this paper is therefore on the modelling and control issues of these wind turbine concepts and especially on their impact on the power system. The models and control are developed...

  5. Noise from wind turbines

    International Nuclear Information System (INIS)

    Andersen, B.; Larsen, P.

    1993-01-01

    Denmark has 3200 wind turbines with an installed maximum capacity of 418MW. The most important Danish research projects into wind turbine noise and the main results are listed. These date from 1983. Two comprehensive studies are currently in progress. The first is an analytical and empirical investigation of aerodynamic noise from wind turbine rotors and has so far dealt mainly with tip noise. The measurement method, using a hard board mounted microphone on the ground near the turbine, is described. Four different tip designs have been tested. Some examples of reference sound power level spectra for three of the designs are presented. During the past two years a computerbased data acquisition system has been used for real-time determination of sound power levels. The second study, which has just commenced, is on annoyance from wind turbine noise. It will include noise measurements, masking calculations and a social survey on the perceived nuisance. (UK)

  6. Computational Models for Nonlinear Aeroelastic Systems, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Clear Science Corp. and Duke University propose to develop and demonstrate a new and efficient computational method of modeling nonlinear aeroelastic systems. The...

  7. Unsteady Design Optimization for Aeroelasticity Applications, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Aeroelasticity plays an important role in the design and development of highly flexible flight vehicles and blended wing body configurations. The operating margins...

  8. Sensitivity Analysis and Error Control for Computational Aeroelasticity, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The objective of this proposal is the development of a next-generation computational aeroelasticity code, suitable for real-world complex geometries, and...

  9. Aeroelastic Simulation Tool for Inflatable Ballute Aerocapture, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — This project will develop a much-needed multidisciplinary analysis tool for predicting the impact of aeroelastic effects on the functionality of inflatable...

  10. Unified Nonlinear Flight Dynamics and Aeroelastic Simulator Tool, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — ZONA Technology, Inc. (ZONA) proposes a R&D effort to develop a Unified Nonlinear Flight Dynamics and Aeroelastic Simulator (UNFDAS) Tool that will combine...

  11. Aeroelastic Simulation Tool for Inflatable Ballute Aerocapture, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This project will develop a much-needed multidisciplinary analysis tool for predicting the impact of aeroelastic effects on the functionality of inflatable...

  12. The effect of wind turbine noise on sleep and quality of life: A systematic review and meta-analysis of observational studies.

    Science.gov (United States)

    Onakpoya, Igho J; O'Sullivan, Jack; Thompson, Matthew J; Heneghan, Carl J

    2015-09-01

    Noise generated by wind turbines has been reported to affect sleep and quality of life (QOL), but the relationship is unclear. Our objective was to explore the association between wind turbine noise, sleep disturbance and quality of life, using data from published observational studies. We searched Medline, Embase, Global Health and Google Scholar databases. No language restrictions were imposed. Hand searches of bibliography of retrieved full texts were also conducted. The reporting quality of included studies was assessed using the STROBE guidelines. Two reviewers independently determined the eligibility of studies, assessed the quality of included studies, and extracted the data. We included eight studies with a total of 2433 participants. All studies were cross-sectional, and the overall reporting quality was moderate. Meta-analysis of six studies (n=2364) revealed that the odds of being annoyed is significantly increased by wind turbine noise (OR: 4.08; 95% CI: 2.37 to 7.04; pwind turbine noise (OR: 2.94; 95% CI: 1.98 to 4.37; pwind turbine noise significantly interfered with QOL. Further, visual perception of wind turbine generators was associated with greater frequency of reported negative health effects. In conclusion, there is some evidence that exposure to wind turbine noise is associated with increased odds of annoyance and sleep problems. Individual attitudes could influence the type of response to noise from wind turbines. Experimental and observational studies investigating the relationship between wind turbine noise and health are warranted. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. The importance of including dynamic soil-structure interaction into wind turbine simulation codes

    DEFF Research Database (Denmark)

    Damgaard, Mads; Andersen, Lars Vabbersgaard; Ibsen, Lars Bo

    2014-01-01

    is examined. The optimal order of the models is determined and implemented into the aeroelastic code HAWC2, where the dynamic response of a 5.0 MW wind turbine is evaluated. In contrast to the fore-aft vibrations, the inclusion of soil-structure interaction is shown to be critical for the side-side vibrations......A rigorous numerical model, describing a wind turbine structure and subsoil, may contain thousands of degrees of freedom, making the approach computationally inefficient for fast time domain analysis. In order to meet the requirements of real-time calculations, the dynamic impedance...... of the wind turbine structure....

  14. PIV study of flow field in Rushton turbine stirred vessel influenced by spatial resolution

    Czech Academy of Sciences Publication Activity Database

    Kotek, M.; Jašíková, D.; Kysela, Bohuš; Šulc, R.; Kopecký, V.

    2017-01-01

    Roč. 2, č. 2017 (2017), s. 79-84 ISSN 2367-8992 R&D Projects: GA ČR GA16-20175S Grant - others:GA MŠk(CZ) LO1201 Institutional support: RVO:67985874 Keywords : mixing process * PIV measurement * spatial resolution Subject RIV: JP - Industrial Processing OBOR OECD: Fluids and plasma physics (including surface physics) http://www.iaras.org/iaras/ home /caijtam/piv-study-of-flow-field-in-rushton-turbine-stirred-vessel-influenced-by-spatial-resolution

  15. Hydraulic turbines

    International Nuclear Information System (INIS)

    Meluk O, G.

    1998-01-01

    The hydraulic turbines are defined according to the specific speed, in impulse turbines and in reaction turbines. Currently, the Pelton turbines (of impulse) and the Francis and Kaplan turbines (of reaction), they are the most important machines in the hydroelectric generation. The hydraulic turbines are capable of generating in short times, large powers, from its loads zero until the total load and reject the load instantly without producing damages in the operation. When the hydraulic resources are important, the hydraulic turbines are converted in the axle of the electric system. Its combination with thermoelectric generation systems, it allow the continuing supply of the variations in demand of energy system. The available hydraulic resource in Colombia is of 93085 MW, of which solely 9% is exploited, become 79% of all the electrical country generation, 21% remaining is provided by means of the thermoelectric generation

  16. Numerical Wake Visualization for Airfoils Undergoing Forced and Aeroelastic Motions

    OpenAIRE

    Jones, K.D.; Center, K.B.

    1996-01-01

    AIAA Paper No. 96-0055, 34th AIAA Aerospace Sciences Meeting, Reno, Nevada, Jan. 1996. A virtual wind tunnel is developed by combining a fast, time-stepping flow solver with an interactive animation interface. Inviscid, incompressible flow solutions are provided by an unsteady, potential-flow code with arbitrary airfoils undergoing forced or aeroelastic motions. Aeroelastic response is predicted by a two-degree-of-freedom spring/mass system modeling the structural dynamics of a flexible wi...

  17. Preliminary studies on the reaction of growing geese (Anser anser f. domestica) to the proximity of wind turbines.

    Science.gov (United States)

    Mikolajczak, J; Borowski, S; Marć-Pieńkowska, J; Odrowaz-Sypniewska, G; Bernacki, Z; Siódmiak, J; Szterk, P

    2013-01-01

    Wind farms produce electricity without causing air pollution and environmental degradation. Unfortunately, wind turbines are a source of infrasound, which may cause a number of physiological effects, such as an increase in cortisol and catecholamine secretion. The impact of infrasound noise, emitted by wind turbines, on the health of geese and other farm animals has not previously been evaluated. Therefore, the aim of this study was to determine the effect of noise, generated by wind turbines, on the stress parameters (cortisol) and the weight gain of geese kept in surrounding areas. The study consisted of 40 individuals of 5-week-old domestic geese Anser anser f domestica, divided into 2 equal groups. The first experimental gaggle (I) remained within 50 m from turbine and the second one (II) within 500 m. During the 12 weeks of the study, noise measurements were also taken. Weight gain and the concentration of cortisol in blood were assessed and significant differences in both cases were found. Geese from gaggle I gained less weight and had a higher concentration of cortisol in blood, compared to individuals from gaggle II. Lower activity and some disturbing changes in behavior of animals from group I were noted. Results of the study suggest a negative effect of the immediate vicinity of a wind turbine on the stress parameters of geese and their productivity.

  18. Internal Structural Design of the Common Research Model Wing Box for Aeroelastic Tailoring

    Science.gov (United States)

    Jutte, Christine V.; Stanford, Bret K.; Wieseman, Carol D.

    2015-01-01

    This work explores the use of alternative internal structural designs within a full-scale wing box structure for aeroelastic tailoring, with a focus on curvilinear spars, ribs, and stringers. The baseline wing model is a fully-populated, cantilevered wing box structure of the Common Research Model (CRM). Metrics of interest include the wing weight, the onset of dynamic flutter, and the static aeroelastic stresses. Twelve parametric studies alter the number of internal structural members along with their location, orientation, and curvature. Additional evaluation metrics are considered to identify design trends that lead to lighter-weight, aeroelastically stable wing designs. The best designs of the individual studies are compared and discussed, with a focus on weight reduction and flutter resistance. The largest weight reductions were obtained by removing the inner spar, and performance was maintained by shifting stringers forward and/or using curvilinear ribs: 5.6% weight reduction, a 13.9% improvement in flutter speed, but a 3.0% increase in stress levels. Flutter resistance was also maintained using straight-rotated ribs although the design had a 4.2% lower flutter speed than the curved ribs of similar weight and stress levels were higher. For some configurations, the differences between curved and straight ribs were smaller, which provides motivation for future optimization-based studies to fully exploit the trade-offs.

  19. Graphene in turbine blades

    Science.gov (United States)

    Das, D. K.; Swain, P. K.; Sahoo, S.

    2016-07-01

    Graphene, the two-dimensional (2D) nanomaterial, draws interest of several researchers due to its many superior properties. It has extensive applications in numerous fields. A turbine is a hydraulic machine which extracts energy from a fluid and converts it into useful work. Recently, Gudukeya and Madanhire have tried to increase the efficiency of Pelton turbine. Beucher et al. have also tried the same by reducing friction between fluid and turbine blades. In this paper, we study the advantages of using graphene as a coating on Pelton turbine blades. It is found that the efficiency of turbines increases, running and maintenance cost is reduced with more power output. By the application of graphene in pipes, cavitation will be reduced, durability of pipes will increase, operation and maintenance cost of water power plants will be less.

  20. Contribution of large scale coherence to wind turbine power: A large eddy simulation study in periodic wind farms

    Science.gov (United States)

    Chatterjee, Tanmoy; Peet, Yulia T.

    2018-03-01

    Length scales of eddies involved in the power generation of infinite wind farms are studied by analyzing the spectra of the turbulent flux of mean kinetic energy (MKE) from large eddy simulations (LES). Large-scale structures with an order of magnitude bigger than the turbine rotor diameter (D ) are shown to have substantial contribution to wind power. Varying dynamics in the intermediate scales (D -10 D ) are also observed from a parametric study involving interturbine distances and hub height of the turbines. Further insight about the eddies responsible for the power generation have been provided from the scaling analysis of two-dimensional premultiplied spectra of MKE flux. The LES code is developed in a high Reynolds number near-wall modeling framework, using an open-source spectral element code Nek5000, and the wind turbines have been modelled using a state-of-the-art actuator line model. The LES of infinite wind farms have been validated against the statistical results from the previous literature. The study is expected to improve our understanding of the complex multiscale dynamics in the domain of large wind farms and identify the length scales that contribute to the power. This information can be useful for design of wind farm layout and turbine placement that take advantage of the large-scale structures contributing to wind turbine power.

  1. Small Horizontal Axis Wind Turbine under High Speed Operation: Study of Power Evaluation

    Science.gov (United States)

    Moh. M. Saad, Magedi; Mohd, Sofian Bin; Zulkafli, Mohd Fadhli Bin; Abdullah, Aslam Bin; Rahim, Mohammad Zulafif Bin; Subari, Zulkhairi Bin; Rosly, Nurhayati Binti

    2017-10-01

    Mechanical energy is produced through the rotation of wind turbine blades by air that convert the mechanical energy into electrical energy. Wind turbines are usually designed to be use for particular applications and design characteristics may vary depending on the area of use. The variety of applications is reflected on the size of turbines and their infrastructures, however, performance enhancement of wind turbine may start by analyzing the small horizontal axis wind turbine (SHAWT) under high wind speed operation. This paper analyzes the implementations of SHAWT turbines and investigates their performance in both simulation and real life. Depending on the real structure of the rotor geometry and aerodynamic test, the power performance of the SHAWT was simulated using ANSYS-FLUENT software at different wind speed up to 33.33 m/s (120km/h) in order to numerically investigate the actual turbine operation. Dynamic mesh and user define function (UDF) was used for revolving the rotor turbine via wind. Simulation results were further validated by experimental data and hence good matching was yielded. And for reducing the energy producing cost, car alternator was formed to be used as a small horizontal wind turbine. As a result, alternator-based turbine system was found to be a low-cost solution for exploitation of wind energy.

  2. Cross-flow turbines: progress report on physical and numerical model studies at large laboratory scale

    Science.gov (United States)

    Wosnik, Martin; Bachant, Peter

    2016-11-01

    Cross-flow turbines show potential in marine hydrokinetic (MHK) applications. A research focus is on accurately predicting device performance and wake evolution to improve turbine array layouts for maximizing overall power output, i.e., minimizing wake interference, or taking advantage of constructive wake interaction. Experiments were carried with large laboratory-scale cross-flow turbines D O (1 m) using a turbine test bed in a large cross-section tow tank, designed to achieve sufficiently high Reynolds numbers for the results to be Reynolds number independent with respect to turbine performance and wake statistics, such that they can be reliably extrapolated to full scale and used for model validation. Several turbines of varying solidity were employed, including the UNH Reference Vertical Axis Turbine (RVAT) and a 1:6 scale model of the DOE-Sandia Reference Model 2 (RM2) turbine. To improve parameterization in array simulations, an actuator line model (ALM) was developed to provide a computationally feasible method for simulating full turbine arrays inside Navier-Stokes models. Results are presented for the simulation of performance and wake dynamics of cross-flow turbines and compared with experiments and body-fitted mesh, blade-resolving CFD. Supported by NSF-CBET Grant 1150797, Sandia National Laboratories.

  3. Sensitivity study of diffuser angle and brim height parameters for the design of 3 kW Diffuser Augmented Wind Turbine

    Science.gov (United States)

    Lipian, Michał; Karczewski, Maciej; Olasek, Krzysztof

    2015-08-01

    The Diffuser Augmented Wind Turbine (DAWT) is an innovative mean to increase the power harvested by wind turbine. By encompassing the rotor with a diffusershaped duct it is possible to increase the flow speed through the turbine by about 40-50%. The study presents the development of a numerical model and its validation by the experiments performed in the wind tunnel of the Institute of Turbomachinery, TUL. Then, the numerical model is used for the geometry sensitivity study to optimize the shape of a diffuser. The paper presents that the DAWT technology has the potential to even double the power outcome of wind turbine when compared to a bare rotor version.

  4. A case-control study of support/opposition to wind turbines: Perceptions of health risk, economic benefits, and community conflict

    International Nuclear Information System (INIS)

    Baxter, Jamie; Morzaria, Rakhee; Hirsch, Rachel

    2013-01-01

    Despite considerable quantitative case study research on communities living with turbines, few have studied the roles played by the perceptions of: health risk, economic benefits/fairness, and intra-community conflict. We report the findings from a case-control survey which compares residents living with/without turbines in their community to understand the relative importance of these variables as predictors of turbine support. Ontario is the context for this study as it is a place where the pace of turbine installations is both very high and extremely politicized. As expected 69% of residents in the case community would vote in favour of local turbines yet surprisingly, only 25% would do so in the control community. Though the literature suggests that aesthetic preferences best predict turbine support the key predictors in this study are: health risk perception, community benefits, general community enhancement, and a preference for turbine-generated electricity. Concern about intra-community conflict is high in both the case (83%) and control (85%) communities as is concern about the fairness of local economic benefits (56% and 62%, respectively); yet neither is significant in the models. We discuss the implications of these findings particularly in terms of the consequences of a technocratic decide-announce-defend model of renewable facility siting. - Highlights: • We compare turbine support in a community living with turbines against a matched control. • We include health risk perception, economic benefits, and community conflict as predictors. • Turbine support is highest in the turbine community and surprisingly low in the control. • Health risk perception and economic benefits consistently predict turbine support. • Economic benefits distribution and conflict are important, but not consistent predictors

  5. Effect of a Bonded Patch on Aeroelastic Behavior of Cantilevered Plates

    Directory of Open Access Journals (Sweden)

    Sirwan Farhadi

    2010-01-01

    Full Text Available In recent years, many researchers have studied vibration suppression of fluttering plates using piezoelectric actuators. Lots of these researchers have focused on optimal placement of piezoelectric patches to obtain maximum controllability. Although mass and stiffness characteristics of bonded patches can alter aeroelastic behavior of fluttering plates, few of them considered the effect of the mentioned parameters in optimization process. This paper investigates effect of a bonded patch on aeroelastic behavior of cantilevered plates in supersonic flow. For this purpose, critical dynamic pressure and limit-cycle oscillations of the system are studied. Von Karman plate theory along with first order piston theory is employed for mathematical simulation of the system. Obtained results reveal that a bonded patch with a small mass ratio can change the system critical dynamic pressure significantly, where the main part of the variations is resulted from the added mass of the bonded patch. The maximum raise of dynamic pressure is acquired when the patch is placed on the plate’s leading edge. The results show that mass and stiffness characteristics of bonded piezoelectric patches can have a great impact on aeroelastic performance of fluttering plates. Therefore, these parameters must be considered as effective factors for optimal placement of piezo-actuators.

  6. Preliminary Assessment of Optimal Longitudinal-Mode Control for Drag Reduction through Distributed Aeroelastic Shaping

    Science.gov (United States)

    Ippolito, Corey; Nguyen, Nhan; Lohn, Jason; Dolan, John

    2014-01-01

    The emergence of advanced lightweight materials is resulting in a new generation of lighter, flexible, more-efficient airframes that are enabling concepts for active aeroelastic wing-shape control to achieve greater flight efficiency and increased safety margins. These elastically shaped aircraft concepts require non-traditional methods for large-scale multi-objective flight control that simultaneously seek to gain aerodynamic efficiency in terms of drag reduction while performing traditional command-tracking tasks as part of a complete guidance and navigation solution. This paper presents results from a preliminary study of a notional multi-objective control law for an aeroelastic flexible-wing aircraft controlled through distributed continuous leading and trailing edge control surface actuators. This preliminary study develops and analyzes a multi-objective control law derived from optimal linear quadratic methods on a longitudinal vehicle dynamics model with coupled aeroelastic dynamics. The controller tracks commanded attack-angle while minimizing drag and controlling wing twist and bend. This paper presents an overview of the elastic aircraft concept, outlines the coupled vehicle model, presents the preliminary control law formulation and implementation, presents results from simulation, provides analysis, and concludes by identifying possible future areas for research

  7. Study on blade surface flow around wind turbine by using LDV measurements

    Science.gov (United States)

    Phengpom, Tinnapob; Kamada, Yasunari; Maeda, Takao; Murata, Junsuke; Nishimura, Shogo; Matsuno, Tasuku

    2015-04-01

    This paper has attempted to study a mechanism of three-dimensional flow around a horizontal axis wind turbine (HAWT) rotor blade. An experimental study of the flow phenomenon in the vicinity of the wind turbine blade is a challenging endeavor. In this research, the HAWT model with 2.4 m diameter was tested in the large wind tunnel. The flow around the rotating blade surface was measured simultaneously for three velocity components, and two probes were used for the synchronized measurement of three-dimensional flow components. The local velocity was detected for the single seeding particle measured in the point where three pairs of laser beams intersected. Blade sections of interest in this study are composed of radial positions r/R = 0.3, 0.5 and 0.7. Optimum and low tip speed ratio flow characteristics were also compared. The velocity flow vector, skin friction coefficient and bound circulation were calculated from LDV measurements, and the experimental research showed reasonably and clearly the experimental results.

  8. Studying Wake Deflection of Wind Turbines in Yaw using Drag Disk Experiments and Actuator Disk Modeling in LES

    Science.gov (United States)

    Howland, Michael; Bossuyt, Juliaan; Meyers, Johan; Meneveau, Charles

    2015-11-01

    Recently, there has been a push towards the optimization in the power output of entire large wind farms through the control of individual turbines, as opposed to operating each turbine in a maximum power point tracking manner. In this vane, the wake deflection by wind turbines in yawed conditions has generated considerable interest in recent years. In order to effectively study the wake deflection according to classical actuator disk momentum theory, a 3D printed drag disk model with a coefficient of thrust of approximately 0.75 - 0.85 and a diameter of 3 cm is used, studied under uniform inflow in a wind tunnel with test section of 1 m by 1.3 m, operating with a negligible inlet turbulence level at an inflow velocity of 10 m/s. Mean velocity profile measurements are performed using Pitot probes. Different yaw angles are considered, including 10, 20, and 30 degrees. We confirm earlier results that (e.g.) a 30 degree yaw angle deflects the center of the wake around 1/2 of a rotor diameter when it impinges on a downstream turbine. Detailed comparisons between the experiments and Large Eddy Simulations using actuator disk model for the wind turbines are carried out in order to help validate the CFD model. Work supported by NSF (grants CBET-113380 and IIA-1243482, the WINDINSPIRE project) and by ERC (ActiveWindFarms, grant no. 306471).

  9. Research in aeroelasticity EFP-2005

    DEFF Research Database (Denmark)

    2006-01-01

    for the determination of 3D angle of attack for rotating blades from either measurements or numerical computations using CFD. A model of the far wake behind windturbines was developed for stability studies of the tip vortices in the far wake. Investigating the blade root region showed that the power efficiency, CP...... design tool was developed. Compared to the Risø-B1family, the new airfoil family showed similar or improved aerodynamic and structural characteristics. Four different airfoils were analyzed to reveal the differences between 2D and 3D CFD. The major conclusions are the dependency of computational...

  10. Advanced turbine systems study system scoping and feasibility study. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1993-04-01

    United Technologies Research Center, Pratt & Whitney Commercial Engine Business, And Pratt & Whitney Government Engine and Space Propulsion has performed a preliminary analysis of an Advanced Turbine System (ATS) under Contract DE-AC21-92MC29247 with the Morgantown Energy Technology Center. The natural gas-fired reference system identified by the UTC team is the Humid Air Turbine (HAT) Cycle in which the gas turbine exhaust heat and heat rejected from the intercooler is used in a saturator to humidify the high pressure compressor discharge air. This results in a significant increase in flow through the turbine at no increase in compressor power. Using technology based on the PW FT4000, the industrial engine derivative of the PW4000, currently under development by PW, the system would have an output of approximately 209 MW and an efficiency of 55.3%. Through use of advanced cooling and materials technologies similar to those currently in the newest generation military aircraft engines, a growth version of this engine could attain approximately 295 MW output at an efficiency of 61.5%. There is the potential for even higher performance in the future as technology from aerospace R&D programs is adapted to aero-derivative industrial engines.

  11. Numerical study on a single bladed vertical axis wind turbine under dynamic stall

    Energy Technology Data Exchange (ETDEWEB)

    Bangga, Galih [Institute of Aerodynamics and Gas Dynamics, University of Stuttgart, Stuttgart (Germany); Hutomo, Go; Sasongko, Herman [Dept. of Mechanical Engineering, Institut Teknologi Sepuluh Nopember, Surabaya (Indonesia); Wiranegara, Raditya [School of Mechanical Aerospace and Civil Engineering, University of Manchester, Manchester (United Kingdom)

    2017-01-15

    The aim of this study is to investigate the flow development of a single bladed vertical axis wind turbine using Computational fluid dynamics (CFD) methods. The blade is constructed using the NACA 0012 profile and is operating under stalled conditions at tip speed ratio of 2. Two dimensional simulations are performed using a commercial CFD package, ANSYS Fluent 15.0, employing the Menter-SST turbulence model. For the preliminary study, simulations of the NACA 0012 airfoil under static conditions are carried out and compared with available measurement data and calculations using the boundary layer code XFOIL. The CFD results under the dynamic case are presented and the resulting aerodynamic forces are evaluated. The turbine is observed to generate negative power at certain azimuth angles which can be divided into three main zones. The blade vortex interaction is observed to strongly influence the flow behavior near the blade and contributes to the power production loss. However, the impact is considered small since it covers only 6.4 % of the azimuth angle range where the power is negative compared to the dynamic stall impact which covers almost 22 % of the azimuth angle range.

  12. Wind tunnel study of a vertical axis wind turbine in a turbulent boundary layer flow

    Science.gov (United States)

    Rolin, Vincent; Porté-Agel, Fernando

    2015-04-01

    Vertical axis wind turbines (VAWTs) are in a relatively infant state of development when compared to their cousins the horizontal axis wind turbines. Very few studies have been carried out to characterize the wake flow behind VAWTs, and virtually none to observe the influence of the atmospheric boundary layer. Here we present results from an experiment carried out at the EPFL-WIRE boundary-layer wind tunnel and designed to study the interaction between a turbulent boundary layer flow and a VAWT. Specifically we use stereoscopic particle image velocimetry to observe and quantify the influence of the boundary layer flow on the wake generated by a VAWT, as well as the effect the VAWT has on the boundary layer flow profile downstream. We find that the wake behind the VAWT is strongly asymmetric, due to the varying aerodynamic forces on the blades as they change their position around the rotor. We also find that the wake adds strong turbulence levels to the flow, particularly on the periphery of the wake where vortices and strong velocity gradients are present. The boundary layer is also shown to cause greater momentum to be entrained downwards rather than upwards into the wake.

  13. Torsional vibration characteristic study of the grid-connected DFIG wind turbine

    Science.gov (United States)

    Yu, Songtao; Xie, Da; Wu, Wangping; Gu, Chenghong; Li, Furong

    2017-01-01

    This paper studies the torsional vibration characteristics of the grid-connected doubly-fed induction generator (DFIG) wind turbine by small signal analysis method. Firstly a detailed small-signal stability union model of the grid-connected DFIG wind turbine is developed, including the mechanical system and electrical system. To study the dynamic characteristic of the blade, gearbox, low speed and high speed shafts, a three mass shaft model for the mechanical system is adopted. At the same time, small signal models of DFIG, the voltage source converter (VSC) and the transmission line of the electrical system are developed respectively. Then, through calculating the eigenvalues of the state matrix A and the corresponding participation factors, the modal analysis is conducted in the shaft torsional vibration issues. And the impact of the system parameters including the series compensation capacitor, the flat-wave reactor, the PI parameters, especially the speed controller of generator rotor on shaft torsional vibration are discussed. The results show that the speed controller strengthens association between the mechanical system and the electrical system, and also produces a low-frequency oscillation mode.

  14. Spar-Type Vertical-Axis Wind Turbines in Moderate Water Depth: A Feasibility Study

    Directory of Open Access Journals (Sweden)

    Ting Rui Wen

    2018-03-01

    Full Text Available The applications of floating vertical-axis wind turbines (VAWTs in deep water have been proposed and studied by several researchers recently. However, the feasibility of deploying a floating VAWT at a moderate water depth has not yet been studied. In this paper, this feasibility is thoroughly addressed by comparing the dynamic responses of spar-type VAWTs in deep water and moderate water depth. A short spar VAWT supporting a 5 MW Darrieus rotor at moderate water depth is proposed by following the deep spar concept in deep water. A fully coupled simulation tool, SIMO-RIFLEX-DMS code, is utilized to carry out time domain simulations under turbulent wind and irregular waves. Dynamic responses of the short spar and deep spar VAWTs are analyzed and compared, including the natural periods, wind turbine performance, platform motions, tower base bending moments, and tension of mooring lines. The statistical characteristics of the thrust and power production for both spars are similar. The comparison of platform motions and tower base bending moments demonstrate a good agreement for both spars, but the short spar has better performance in surge/sway motions and side–side bending moments. The 2P response dominates the bending moment spectra for both spars. A significant variation in tension of Mooring Line 1 and a larger corresponding spectrum value are found in the short spar concept. The results indicate that the application of short spar VAWTs is feasible and could become an alternative concept at moderate water depth.

  15. Wind Turbine Loads Induced by Terrain and Wakes: An Experimental Study through Vibration Analysis and Computational Fluid Dynamics

    Directory of Open Access Journals (Sweden)

    Francesco Castellani

    2017-11-01

    Full Text Available A wind turbine is a very well-known archetype of energy conversion system working at non-stationary regimes. Despite this, a deep mechanical comprehension of wind turbines operating in complicated conditions is still challenging, especially as regards the analysis of experimental data. In particular, wind turbines in complex terrain represent a very valuable testing ground because of the possible combination of wake effects among nearby turbines and flow accelerations caused by the terrain morphology. For these reasons, in this work, a cluster of four full-scale wind turbines from a very complex site is studied. The object of investigation is vibrations, at the level of the structure (tower and drive-train. Data collected by the on-board condition monitoring system are analyzed and interpreted in light of the knowledge of wind conditions and operating parameters collected by the Supervisory Control And Data Acquisition (SCADA. A free flow Computational Fluid Dynamics (CFD simulation is also performed, and it allows one to better interpret the vibration analysis. The main outcome is the interpretation of how wakes and flow turbulences appear in the vibration signals, both at the structural level and at the drive-train level. Therefore, this wind to gear approach builds a connection between flow phenomena and mechanical phenomena in the form of vibrations, representing a precious tool for assessing loads in different working conditions.

  16. Potential health impact of wind turbines

    International Nuclear Information System (INIS)

    2010-05-01

    In response to public health concerns about wind turbines, a study was conducted to review the scientific evidence on the potential health effects of wind turbines. Several research questions were examined, including scientific evidence on the potential health impacts of wind turbines; the relationship between wind turbine noise and health; the relationship between low frequency sound, infrasound and health; assessment of exposure to wind turbines; wind turbine health and safety hazards and Ontario wind turbine setbacks; community consultation prior to wind farm construction and data gaps and research needs. The study showed that although some people living near wind turbines reported symptoms such as dizziness, headaches, and sleep disturbance, the scientific evidence available to date does not demonstrate a direct causal link between wind turbine noise and adverse health effects. The sound level from wind turbines at common residential setbacks is not sufficient to cause hearing impairment or other direct health effects, although some people may find it annoying. 41 refs., 1 appendix.

  17. Potential health impact of wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2010-05-15

    In response to public health concerns about wind turbines, a study was conducted to review the scientific evidence on the potential health effects of wind turbines. Several research questions were examined, including scientific evidence on the potential health impacts of wind turbines; the relationship between wind turbine noise and health; the relationship between low frequency sound, infrasound and health; assessment of exposure to wind turbines; wind turbine health and safety hazards and Ontario wind turbine setbacks; community consultation prior to wind farm construction and data gaps and research needs. The study showed that although some people living near wind turbines reported symptoms such as dizziness, headaches, and sleep disturbance, the scientific evidence available to date does not demonstrate a direct causal link between wind turbine noise and adverse health effects. The sound level from wind turbines at common residential setbacks is not sufficient to cause hearing impairment or other direct health effects, although some people may find it annoying. 41 refs., 1 appendix.

  18. Self Evolving Neural Network Based Algorithm for Fault Prognosis in Wind Turbines : A Case Study

    OpenAIRE

    Bangalore, Pramod; Bertling Tjernberg, Lina

    2014-01-01

    Asset management of wind turbines has gained increased importance in recent years. High maintenance cost and longer downtimes of wind turbines have led to research in methods to optimize maintenance activities. Condition monitoring systems have proven to be a useful tool towards aiding maintenance management of wind turbines. Methods using Supervisory Control and Data Acquisition (SCADA) system along with artificial intelligence (AI) methods have been developed to monitor the condition of win...

  19. Preliminary study of nuclear power cogeneration system using gas turbine process

    Energy Technology Data Exchange (ETDEWEB)

    Fumizawa, Motoo; Inaba, Yoshitomo; Hishida, Makoto [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Ogawa, Masuro; Ogata, Kann; Yamada, Seiya

    1995-12-01

    The Nuclear power generation plant (NPGP) releases smaller amount of carbon dioxide than the fossil power plant for the generation of the unit electrical power. Thus, the NPGP is expected to contribute resolving the ecological problems. It is important to investigate the nuclear power cogeneration system using gas turbine process from the view point that it is better to produce electricity in high thermal efficiency from the high temperature energy. We carried out, in the current preliminary study, the survey and selection of the candidate cycles, then conducted the evaluation of cycle efficiency, the selection of R and D items to be solved for the decision of the optimum cycle. Following this, we evaluated nuclear heat application for intermediate and low temperature level released from gas turbine process and overall efficiency of cogeneration system. As a result, it was clarified that overall efficiency of the direct regenerative cycle was the highest in low temperature region below 200degC, and that of the direct regenerative inter cooling cycle was the highest in middle and high temperature region. (author).

  20. Environmental feasibility study for deployment and construction of mobile gas turbine power plants in urbanized areas

    Directory of Open Access Journals (Sweden)

    Bryukhan Fedor

    2017-01-01

    Full Text Available In the view of current electrical shortage in some regions of Russia, mobile gas turbine power plants (MGTPP have become urgent in recent years. Usually they are used as back-up power sources to cover peak loads in power networks and to ensure uninterrupted power supply to consumers. This paper deals with environmental feasibility study for deployment and construction of the MGTPP in an urban setting. Technogehic factors of the MGTPP impact on the environment have been assessed and possibility of the MGTPP deployment at various sites in different regions of Russia has been identified. The necessity of using the technology of water injection into the gas turbine units combustion chamber to suppress nitrogen oxides in some cases is mentioned. Quantitative assessments of the MGTPP technogehic impact on the environment components have been performed using standard techniques. The calculations have revealed that the MGTPP specifications ensure the levels of technogehic impacts within the standard limits. The results have ensured preparation of pre-design and design documentation related to protection of the environment against the MGTPP complex technogehic impact.

  1. Flicker Study on Variable Speed Wind Turbines with Permanent Magnet Synchronous Generator

    DEFF Research Database (Denmark)

    Hu, Weihao; Chen, Zhe; Wang, Yue

    2008-01-01

    Grid connected wind turbines are fluctuating power sources that may produce flicker during continuous operation. This paper presents a simulation model of a MW-level variable speed wind turbines with a permanent magnet synchronous generator (PMSG) and a full-scale converter developed in the simul......Grid connected wind turbines are fluctuating power sources that may produce flicker during continuous operation. This paper presents a simulation model of a MW-level variable speed wind turbines with a permanent magnet synchronous generator (PMSG) and a full-scale converter developed...

  2. Study on the glaze ice accretion of wind turbine with various chord lengths

    Science.gov (United States)

    Liang, Jian; Liu, Maolian; Wang, Ruiqi; Wang, Yuhang

    2018-02-01

    Wind turbine icing often occurs in winter, which changes the aerodynamic characteristics of the blades and reduces the work efficiency of the wind turbine. In this paper, the glaze ice model is established for horizontal-axis wind turbine in 3-D. The model contains the grid generation, two-phase simulation, heat and mass transfer. Results show that smaller wind turbine suffers from more serious icing problem, which reflects on a larger ice thickness. Both the collision efficiency and heat transfer coefficient increase under smaller size condition.

  3. Steam Turbines

    Science.gov (United States)

    1981-01-01

    Turbonetics Energy, Inc.'s steam turbines are used as power generating systems in the oil and gas, chemical, pharmaceuticals, metals and mining, and pulp and paper industries. The Turbonetics line benefited from use of NASA research data on radial inflow steam turbines and from company contact with personnel of Lewis Research Center, also use of Lewis-developed computer programs to determine performance characteristics of turbines.

  4. Influence of Characteristic-Soil-Property-Estimation Approach on the Response of Monopiles for Offshore Wind Turbines

    DEFF Research Database (Denmark)

    Andersen, Lars Vabbersgaard; Sørensen, John Dalsgaard; Kim, Sun-Bin

    2015-01-01

    , and pile–soil interaction is modelled by the Winkler approach with nonlinear p–y curves for the soil resistance. The 5MW NREL reference wind turbine is employed for load estimation, utilizing the aeroelastic code FAST. The study includes comparison of monopile capacities based on a single CPT as well......Different approaches to estimation of the characteristic undrained shear strength of soil are discussed, based on 12 cone penetration tests (CPTs) carried out within a soil volume representative of an offshore monopile foundation. The paper is focused on the statistical treatment of the data...... as multiple CPTs. Comparisons are made between results obtained from a single CPT and those from all the CPTs at the site. The influence of assuming few or many layers in the deterministic soil model is assessed, and different assumptions regarding the statistical distribution of the data are compared...

  5. Effect of Wind Turbine Noise on Workers' Sleep Disorder: A Case Study of Manjil Wind Farm in Northern Iran

    Science.gov (United States)

    Abbasi, Milad; Monnazzam, Mohammad Reza; Zakerian, Sayedabbolfazl; Yousefzadeh, Arsalan

    2015-04-01

    Noise from wind turbines is one of the most important factors affecting the health, welfare, and human sleep. This research was carried out to study the effect of wind turbine noise on workers' sleep disorder. For this, Manjil Wind Farm, because of the greater number of staff and turbines than other wind farms in Iran, was chosen as case study. A total number of 53 participants took part in this survey. They were classified into three groups of mechanics, security, and official. In this study, daytime sleepiness data of workers were gathered using Epworth Sleepiness Scales (ESS) was used to determine the level of daytime sleepiness among the workers. The 8-h equivalent sound level (LAeq,8h) was measured to determine the individuals' exposure at each occupational group. Finally, the effect of sound, age, and workers' experience on individuals' sleep disorder was analyzed through multiple regression analysis in the R software. The results showed that there was a positive and significant relationship between age, workers' experience, equivalent sound level, and the level of sleep disorder. When age is constant, sleep disorder will increase by 26% as per each 1 dB increase in equivalent sound level. In situations where equivalent sound level is constant, an increase of 17% in sleep disorder is occurred as per each year of work experience. Because of the difference in sound exposure in different occupational groups. The effect of noise in repairing group was about 6.5 times of official group and also 3.4 times of the security group. Sleep disorder effect caused by wind turbine noise in the security group is almost two times more than the official group. Unlike most studies on wind turbine noise that address the sleep disorder among inhabitants nearby wind farms, this study, for the first time in the world, examines the impact of wind turbine noise on sleep disorder of workers who are more closer to wind turbines and exposed to higher levels of noise. So despite all the

  6. Studies on water turbine runner which fish can pass through: In case of single stage axial runner

    International Nuclear Information System (INIS)

    Shimizu, Yukimari; Maeda, Takao; Nagoshi, Osamu; Ieda, Kazuma; Shinma, Hisako; Hagimoto, Michiko

    1994-01-01

    The relationship between water turbine runner design and operation and the safe passage of fish through the turbine is studied. The kinds of fish used in the tests are a dace, a sweet fish and a small salmon. A single stage axial runner is used. The velocity and pressure distributions were measured inside the turbine casing and along the casing wall. Many pictures showing fish passing through the rotating runner were taken and analyzed. The swimming speed of the fish was examined from video recordings. Fish pass through the runner more rapidly when they can determine and choose the easier path. Injury and mortality of fish are affected by the runner speed and the location of impact of the runner on the fish body

  7. A Comparative Assessment of Wind Turbine Innovation and Diffusion Policies. Historical Case Studies of Energy Technology Innovation

    DEFF Research Database (Denmark)

    Neij, Lena; Andersen, Per Dannemand

    2012-01-01

    Wind turbines have become a mainstream technology, a first choice for many when investing in new electricity generation facilities. This comparative case study addresses how governmental policy has been formulated to support the wind turbine innovation and diffusion process. Three innovation stages...... path of the 1980s. The third stage is the emerging markets of the 1990s and 2000s, including countries such as India and China. Within these different stages, common elements in government policy strategies can be identified as essential for a sustainable and successful innovation process. These can...

  8. Added-Mass Effects on a Horizontal-Axis Tidal Turbine Using FAST v8

    Energy Technology Data Exchange (ETDEWEB)

    Murray, Robynne [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Thresher, Robert W [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Jonkman, Jason [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2018-04-09

    Added mass on tidal turbine blades has the potential to alter the blade dynamic response, such as natural frequencies and vibration amplitudes, as a response to blade acceleration. Currently, most aeroelastic design tools do not consider such effects as they are complex and expensive to model, and they are not an intrinsic part of most blade-element momentum theory codes, which are commonly used in the tidal energy industry. This article outlines the addition of added-mass effects to the National Renewable Energy Laboratory's design tool FAST v8. A verification is presented for a spring-mass system with an initial displacement, and a case study is performed for the Reference Model 1 20-m-diameter tidal turbine. For the 20-m-diameter turbine, it was shown that the natural frequency of vibration is reduced by 65% when added mass is considered. Further, the thrust loads are increased by 2.5% when the blades are excited by a 5% step increase in inflow velocity when added mass is considered. This decrease can have a significant impact on the overall turbine design, as it is important to design the blades with a natural frequency so that they are not excited by the rotor speed and its harmonics, wherein aerodynamic excitation can lead to fatigue damage. However, it was shown that when turbulent inflow with an intensity of 20% was modeled, there was almost no impact on the loads and blade displacement with added-mass effects except for a small difference in the fatigue response of the blade to turbulent load fluctuations.

  9. Abnormally High Power Output of Wind Turbine in Cold Weather: A Preliminary Study

    Directory of Open Access Journals (Sweden)

    Christophe Leclerc

    2003-01-01

    Full Text Available According to popular belief, air temperature effects on wind turbine power output are produced solely by air density variations, and power is proportional to air density. However, some cases have been reported, all involving stall-controlled wind turbines, in which unexpected high power output was observed at very low temperatures.

  10. Flicker study on variable speed wind turbines with doubly fed induction generators

    DEFF Research Database (Denmark)

    Sun, Tao; Chen, Zhe; Blaabjerg, Frede

    2005-01-01

    to a conclusion that the factors mentioned above have different influences on flicker emission compared with that in the case of the fixed speed wind turbine. Flicker mitigation is realized by output reactive power control of the variable speed wind turbine with doubly fed induction generator. Simulation results...

  11. An experimental study of the stable and unstable operation of an LPP gas turbine combustor

    Science.gov (United States)

    Dhanuka, Sulabh Kumar

    A study was performed to better understand the stable operation of an LPP combustor and formulate a mechanism behind the unstable operation. A unique combustor facility was developed at the University of Michigan that incorporates the latest injector developed by GE Aircraft Engines and enables operation at elevated pressures with preheated air at flow-rates reflective of actual conditions. The large optical access has enabled the use of a multitude of state-of-the-art laser diagnostics such as PIV and PLIF, and has shed invaluable light not only into the GE injector specifically but also into gas turbine combustors in general. Results from Particle Imaging Velocimetry (PIV) have illustrated the role of velocity, instantaneous vortices, and key recirculation zones that are all critical to the combustor's operation. It was found that considerable differences exist between the iso-thermal and reacting flows, and between the instantaneous and mean flow fields. To image the flame, Planar Laser Induced Fluorescence (PLIF) of the formaldehyde radical was successfully utilized for the first time in a Jet-A flame. Parameters regarding the flame's location and structure have been obtained that assist in interpreting the velocity results. These results have also shown that some of the fuel injected from the main fuel injectors actually reacts in the diffusion flame of the pilot. The unstable operation of the combustor was studied in depth to obtain the stability limits of the combustor, behavior of the flame dynamics, and frequencies of the oscillations. Results from simultaneous pressure and high speed chemiluminescence images have shown that the low frequency dynamics can be characterized as flashback oscillations. The results have also shown that the stability of the combustor can be explained by simple and well established premixed flame stability mechanisms. This study has allowed the development of a model that describes the instability mechanism and accurately

  12. Validation of Simplified Load Equations Through Loads Measurement and Modeling of a Small Horizontal-Axis Wind Turbine Tower

    Energy Technology Data Exchange (ETDEWEB)

    Dana, Scott [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Van Dam, Jeroen J [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Damiani, Rick R [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2018-04-24

    As part of an ongoing effort to improve the modeling and prediction of small wind turbine dynamics, the National Renewable Energy Laboratory (NREL) tested a small horizontal-axis wind turbine in the field at the National Wind Technology Center. The test turbine was a 2.1-kW downwind machine mounted on an 18-m multi-section fiberglass composite tower. The tower was instrumented and monitored for approximately 6 months. The collected data were analyzed to assess the turbine and tower loads and further validate the simplified loads equations from the International Electrotechnical Commission (IEC) 61400-2 design standards. Field-measured loads were also compared to the output of an aeroelastic model of the turbine. In particular, we compared fatigue loads as measured in the field, predicted by the aeroelastic model, and calculated using the simplified design equations. Ultimate loads at the tower base were assessed using both the simplified design equations and the aeroelastic model output. The simplified design equations in IEC 61400-2 do not accurately model fatigue loads and a discussion about the simplified design equations is discussed.

  13. Study for the optimization of a transport aircraft wing for maximum fuel efficiency. Volume 1: Methodology, criteria, aeroelastic model definition and results

    Science.gov (United States)

    Radovcich, N. A.; Dreim, D.; Okeefe, D. A.; Linner, L.; Pathak, S. K.; Reaser, J. S.; Richardson, D.; Sweers, J.; Conner, F.

    1985-01-01

    Work performed in the design of a transport aircraft wing for maximum fuel efficiency is documented with emphasis on design criteria, design methodology, and three design configurations. The design database includes complete finite element model description, sizing data, geometry data, loads data, and inertial data. A design process which satisfies the economics and practical aspects of a real design is illustrated. The cooperative study relationship between the contractor and NASA during the course of the contract is also discussed.

  14. Effects of soil–structure interaction on real time dynamic response of offshore wind turbines on monopiles

    DEFF Research Database (Denmark)

    Damgaard, M.; Zania, Varvara; Andersen, L.V.

    2014-01-01

    , a computationally efficient modelling approach of including the dynamic soil–structure interaction into aeroelastic codes is presented with focus on monopile foundations. Semi-analytical frequency-domain solutions are applied to evaluate the dynamic impedance functions of the soil–pile system at a number...... normal operating mode. The aeroelastic response is evaluated for three different foundation conditions, i.e. apparent fixity length, the consistent lumped-parameter model and fixed support at the seabed. The effect of soil–structure interaction is shown to be critical for the design, estimated in terms......Offshore wind turbines are highly dynamically loaded structures, their response being dominated by the interrelation effects between the turbine and the support structure. Since the dynamic response of wind turbine structures occurs in a frequency range close to the excitation frequencies related...

  15. Experimental studies of Savonius wind turbines with variations sizes and fin numbers towards performance

    Science.gov (United States)

    Utomo, Ilham Satrio; Tjahjana, Dominicus Danardono Dwi Prija; Hadi, Syamsul

    2018-02-01

    The use of renewable energy in Indonesia is still low. Especially the use of wind energy. Wind turbine Savonius is one turbine that can work with low wind speed. However, Savonius wind turbines still have low efficiency. Therefore it is necessary to modify. Modifications by using the fin are expected to increase the positive drag force by creating a flow that can enter the overlap ratio of the gap. This research was conducted using experimental approach scheme. Parameters generated from the experiment include: power generator, power coefficient, torque coefficient. The experimental data will be collected by variation of fin area, horizontal finning, at wind speed 3 m/s - 4,85 m/s. Experimental results show that with the addition of fin can improve the performance of wind turbine Savonius 11%, and by using the diameter of 115 mm fin is able to provide maximum performance in wind turbine Savonius.

  16. Study on transient stability of wind turbine with induction generator based on variable pitch control strategy

    DEFF Research Database (Denmark)

    Zhao, B.; Li, H.; Han, L.

    2011-01-01

    In order to enhance and improve the transient stability of a grid-connected wind turbine generator system under the power grid fault, based on typical pitch control strategy of wind turbine, considering the wind turbine system oscillation caused by the drive-train shaft flexibility, Based on Matlab....../Simulink, electromagnetic transient state models of the wind tubine generator system and the pitch control models were presented, and the transient behaviors of the wind turbine genarator system using the typical and the proposed pitch control strategies were analyzed and compared when the power grid was subjected...... to a three-phase short-circuit fault. Also the results were compared with using reactive compensation device. The simulation results show that the proposed pitch control strategy can effectively improve the transient stability of wind turbine generator system....

  17. Study on transient stability of wind turbine with induction generator based on variable pitch control strategy

    DEFF Research Database (Denmark)

    Zhao, B.; Li, H.; Han, L.

    2011-01-01

    In order to enhance and improve the transient stability of a grid-connected wind turbine generator system under the power grid fault, based on typical pitch control strategy of wind turbine, considering the wind turbine system oscillation caused by the drive-train shaft flexibility, Based on Matlab...... to a three-phase short-circuit fault. Also the results were compared with using reactive compensation device. The simulation results show that the proposed pitch control strategy can effectively improve the transient stability of wind turbine generator system......./Simulink, electromagnetic transient state models of the wind tubine generator system and the pitch control models were presented, and the transient behaviors of the wind turbine genarator system using the typical and the proposed pitch control strategies were analyzed and compared when the power grid was subjected...

  18. Comparative Study of Voltage Recovery Behaviors of Grid-Connected Wind Turbines

    DEFF Research Database (Denmark)

    Sun, Tao; Chen, Zhe; Blaabjerg, Frede

    2004-01-01

    The fast development of wind power generation brings new requirements for wind turbine integration to the network. After the clearance of an external short-circuit fault, the voltage at the wind turbine terminal should be re-established with minimized power losses. This paper concentrates...... on voltage recovery of variable speed wind turbines. The models of two different kinds of variable speed wind turbines, respectively with slip control and with doubly fed induction generator (DFIG), are developed in PSCAD/EMTDC. In both wind power generation systems, control strategies are proposed to re......-establish the wind turbine terminal voltage after the clearance of an external short-circuit fault, which have been demonstrated by simulation results....

  19. A Large-Eddy Simulation Study of Vertical Axis Wind Turbine Wakes in the Atmospheric Boundary Layer

    Directory of Open Access Journals (Sweden)

    Sina Shamsoddin

    2016-05-01

    Full Text Available In a future sustainable energy vision, in which diversified conversion of renewable energies is essential, vertical axis wind turbines (VAWTs exhibit some potential as a reliable means of wind energy extraction alongside conventional horizontal axis wind turbines (HAWTs. Nevertheless, there is currently a relative shortage of scientific, academic and technical investigations of VAWTs as compared to HAWTs. Having this in mind, in this work, we aim to, for the first time, study the wake of a single VAWT placed in the atmospheric boundary layer using large-eddy simulation (LES. To do this, we use a previously-validated LES framework in which an actuator line model (ALM is incorporated. First, for a typical three- and straight-bladed 1-MW VAWT design, the variation of the power coefficient with both the chord length of the blades and the tip-speed ratio is analyzed by performing 117 simulations using LES-ALM. The optimum combination of solidity (defined as N c / R , where N is the number of blades, c is the chord length and R is the rotor radius and tip-speed ratio is found to be 0.18 and 4.5, respectively. Subsequently, the wake of a VAWT with these optimum specifications is thoroughly examined by showing different relevant mean and turbulence wake flow statistics. It is found that for this case, the maximum velocity deficit at the equator height of the turbine occurs 2.7 rotor diameters downstream of the center of the turbine, and only after that point, the wake starts to recover. Moreover, it is observed that the maximum turbulence intensity (TI at the equator height of the turbine occurs at a distance of about 3.8 rotor diameters downstream of the turbine. As we move towards the upper and lower edges of the turbine, the maximum TI (at a certain height increases, and its location moves relatively closer to the turbine. Furthermore, whereas both TI and turbulent momentum flux fields show clear vertical asymmetries (with larger magnitudes at the

  20. Design study of power conversion system for the gas turbine high temperature reactor (GTHTR300)

    International Nuclear Information System (INIS)

    Takada, Shoji; Takizuka, Takakazu; Kunitomi, Kazuhiko; Yan, Xing; Katanishi, Shoji; Kosugiyama, Shinichi; Miyoshi, Yasuyuki

    2002-01-01

    A design study of the power conversion system for the Gas Turbine High Temperature Reactor (GTHTR300) was carried out. The study aimed at reducing the total mass of main system components, which simplified system configuration by selecting the non-inter-cooled cycle, and improvement of the performance of power conversion components to enhance economics. The 3-dimensional aerodynamic design of the turbine and compressor achieved high polytropic efficiencies of 93 and 90%, respectively, while reducing the differential thrust of the turbo-compressor to 10 kN as well as keeping a high surge margin of 30% for the compressor, which made it possible to attain a high power conversion efficiency of 45.8%. A horizontal turbo-machine layout, in which the turbo-compressor and generator rotors were connected by a diaphragm-coupling, was proposed to lessen the load requirements for magnetic bearings. The turbo-machine rotor, which passed over critical speeds of bending mode, fulfilled the standard limit of vibration amplitude of 75 μm at the rated rotational speed by optimizing the stiffness of the magnetic bearings. The main focus of the heat exchanger design was size and mass minimization, while fulfilling the target temperature efficiency of 95%. The plate-fin type recuperator employed an off-set fin arrangement, having a square cross section of 1.2 mm x 1.2 mm. The pre-cooler employed helical-coil tubes with low lateral fins. The present study is entrusted from the Ministry of Education, Culture, Sports, Science and Technology of Japan. (author)

  1. Rigid MATLAB drivetrain model of a 500 kW wind turbine for predicting maximum gear tooth stresses in a planetary gearbox using multibody gear constraints

    DEFF Research Database (Denmark)

    Jørgensen, Martin Felix; Pedersen, Niels Leergaard; Sørensen, Jens Nørkær

    2014-01-01

    The aeroelastic FLEX 5 code and a semi-advanced rigid multibody model has been utilized for simulating drivetrain forces and moments in a real 500 kW wind turbine. Experimental validation is carried out with results based on known physical properties of the blades, tower, hub, gearbox, shaft and ...

  2. A study on high speed coupling design for wind turbine using a finite element analysis

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hyoung Woo; Kang, Jong Hun [Dept. of Mechatronics Engineering, Jungwon University, Geosan (Korea, Republic of); Han, Jeong Young [Pusan Educational Center for Computer Aided Machine Design, Pusan University, Busan (Korea, Republic of)

    2016-08-15

    The purpose of this study is to design a high speed coupling for 3 MW wind turbines and evaluate its structural stability. A basic analysis was performed to assess the structural stability of two materials, SPS6 steel plate and a composite material (Glass7628, Glass/Epoxy), in relation to misalignment in the axial and radial directions. The entire model was analyzed for a high speed coupling based on the SPS6 steel plate, which was found to have higher stability among the two materials, and safety factors were estimated for various levels of power delivery. To test the proposed high speed coupling design, a performance test was carried out to verify the stability of the final product.

  3. Compliance effects on dynamically pitching wind turbine airfoils

    Science.gov (United States)

    Magstadt, Andrew S.

    The effects of elastic compliance in dynamically pitching wind turbine blades have been investigated. A numerical model guided wind tunnel testing, which used unsteady surface pressure measurements and phase-locked Particle Imaging Velocimetry to gather aerodynamic information. Using a torsionally compliant member, aeroelastic effects on the unsteady aerodynamics were compared against the results from a corresponding rigidly pitching airfoil to isolate the effects of compliance. The novel experimental apparatus and data acquisition techniques developed at the University of Wyoming showed that the presence of compliance can alter flow-field structures and increase dynamic loading. The high sensitivity of this nonlinear system suggests the formation of fluid-structure instabilities in large-scale turbines and demonstrates the potential for aerodynamic control as a means to mitigate adverse loading effects and improve wind turbine efficiency.

  4. Impact of fault ride-through requirements on fixed-speed wind turbine structural loads

    DEFF Research Database (Denmark)

    Hansen, Anca Daniela; Cutululis, Nicolaos Antonio; Markou, Helen

    2011-01-01

    simulation tools, which have expertise in different specialized wind turbines design areas. Two complimentary simulation tools are considered i.e. the detailed power system simulation tool PowerFactory from DIgSILENT and the advanced aeroelastic computer code HAWC2, in order to assess of the dynamic response...... by performing a rainflow and a statistical analysis for fatigue and ultimate structural loads, respectively. Two cases are compared i.e. one where the turbine is immediately disconnected from the grid when a grid fault occurs and one where the turbine is equipped with a fault ride-through controller...... faults. This article proposes a computer approach for the quantification of the wind turbines structural loads caused by the fault ride-through grid requirements. This approach, exemplified for the case of a 2MW active stall wind turbine, relies on the combination of knowledge from complimentary...

  5. Movement and collision of Lagrangian particles in hydro-turbine intakes: a case study

    Energy Technology Data Exchange (ETDEWEB)

    Romero-Gomez, Pedro [Research Engineer, Hydrology Group, Pacific Northwest National Laboratory, Richland, WA 99354, USA; Richmond, Marshall C. [(IAHR Member), Chief Engineer, Hydrology Group, Pacific Northwest National Laboratory, Richland, WA 99354, USA

    2017-03-03

    Studies of the stress/survival of migratory fish during downstream passage through operating hydro-turbines are normally conducted to determine the fish-friendliness of units. One field approach consisting of recording extreme hydraulics with autonomous sensors is largely sensitive to the conditions of sensor release and the initial trajectories at the turbine intake. This study applies a modelling strategy based on flow simulations using computational fluid dynamics and Lagrangian particle tracking to represent the travel of live fish and autonomous sensor devices through hydro-turbine intakes. For the flow field calculation, the simulations were conducted with both a time-averaging turbulence model and an eddy-resolving technique. For the particle tracking calculation, different modelling assumptions for turbulence forcing, mass formulation, buoyancy, and release condition were tested. The modelling assumptions are evaluated with respect to data sets collected using a laboratory physical model and an autonomous sensor device deployed at Ice Harbor Dam (Snake River, State of Washington, U.S.A.) at the same discharge and release point as in the present computer simulations. We found an acceptable agreement between the simulated results and observed data and discuss relevant features of Lagrangian particle movement that are critical in turbine design and in the experimental design of field studies.

  6. Advanced Turbine Systems (ATS). Phase 1: System scoping and feasibility studies

    Science.gov (United States)

    White, D. J.

    1993-04-01

    As part of this involvement, Solar intends to design and commercialize a unique gas turbine system that promises high cycle efficiencies and low exhaust emissions. This engine of approximately 12-MW will be targeted for the dispersed power markets both urban and rural. Goals of 50% thermal efficiency and 8 parts-per-million by volume (ppmv) nitrogen oxide emissions were established. Reliability, availability, and maintainability (RAM) will continue to be the most important factors in the competitive marketplace. The other major goal adopted was one of reducing the cost of power produced by 10%. This reduction is based on the cost of power (COP) associated with today's engines that lie in the same horsepower range as that targeted in this study. An advanced cycle based on an approximation of the Ericsson Cycle was adopted after careful studies of a number of different cycles. This advanced intercooled, recuperated engine when fired at 2450 F will be capable of meeting the 50% efficiency goal if the cooling air requirements do not exceed 7% of the total air flow rate. This latter qualification will probably dictate the use of ceramic parts for both the nozzle guide vanes and the turbine blades. Cooling of these parts will probably be required and the 7% cooling flow allowance is thought to be adequate for such materials. Analyses of the cost of power and RAM goals show that the installed cost of this advanced engine can be approximately 50% above today's costs. This cost is based on $4.00 per million Btu fuel and a COP reduction of 10% while maintaining the same RAM as today's engines.

  7. Case Studies of Fatigue Life Improvement Using Low Plasticity Burnishing in Gas Turbine Engine Applications

    Science.gov (United States)

    Prevey, Paul S.; Shepard, Michael; Ravindranath, Ravi A.; Gabb, Timothy

    2003-01-01

    Surface enhancement technologies such as shot peening, laser shock peening (LSP), and low plasticity burnishing (LPB) can provide substantial fatigue life improvement. However, to be effective, the compressive residual stresses that increase fatigue strength must be retained in service. For successful integration into turbine design, the process must be affordable and compatible with the manufacturing environment. LPB provides thermally stable compression of comparable magnitude and even greater depth than other methods, and can be performed in conventional machine shop environments on CNC machine tools. LPB provides a means to extend the fatigue lives of both new and legacy aircraft engines and ground-based turbines. Improving fatigue performance by introducing deep stable layers of compressive residual stress avoids the generally cost prohibitive alternative of modifying either material or design. The X-ray diffraction based background studies of thermal and mechanical stability of surface enhancement techniques are briefly reviewed, demonstrating the importance of minimizing cold work. The LPB process, tooling, and control systems are described. An overview of current research programs conducted for engine OEMs and the military to apply LPB to a variety of engine and aging aircraft components are presented. Fatigue performance and residual stress data developed to date for several case studies are presented including: * The effect of LPB on the fatigue performance of the nickel based super alloy IN718, showing fatigue benefit of thermal stability at engine temperatures. * An order of magnitude improvement in damage tolerance of LPB processed Ti-6-4 fan blade leading edges. * Elimination of the fretting fatigue debit for Ti-6-4 with prior LPB. * Corrosion fatigue mitigation with LPB in Carpenter 450 steel. *Damage tolerance improvement in 17-4PH steel. Where appropriate, the performance of LPB is compared to conventional shot peening after exposure to engine

  8. Wind turbines and infrasound

    International Nuclear Information System (INIS)

    Howe, B.

    2006-01-01

    This paper provided the results of a study conducted to assess the impacts of wind farm-induced infrasound on nearby residences and human populations. Infrasound occurs at frequencies below those considered as detectable by human hearing. Infrasonic levels caused by wind turbines are often similar to ambient levels of 85 dBG or lower that are caused by wind in the natural environment. This study examined the levels at which infrasound poses a threat to human health or can be considered as an annoyance. The study examined levels of infrasound caused by various types of wind turbines, and evaluated acoustic phenomena and characteristics associated with wind turbines. Results of the study suggested that infrasound near modern wind turbines is typically not perceptible to humans through either auditory or non-auditory mechanisms. However, wind turbines often create an audible broadband noise whose amplitude can be modulated at low frequencies. A review of both Canadian and international studies concluded that infrasound generated by wind turbines should not significantly impact nearby residences or human populations. 17 refs., 2 tabs., 4 figs

  9. Unbalanced voltage faults: the impact on structural loads of doubly fed asynchronous generator wind turbines

    DEFF Research Database (Denmark)

    Barahona Garzón, Braulio; Cutululis, Nicolaos Antonio; Hansen, Anca Daniela

    2014-01-01

    , and control dynamics in an integrated simulation environment based on an aeroelastic code (HAWC2) and software for control design (Matlab/Simulink). In the present analysis, 1 Hz equivalent loads are used to compare fatigue loads, whereas maximum–minimum values are used to compare extreme loads. A control......This paper investigates the impact that unbalanced voltage faults have on wind turbine structural loads. In such cases, electromagnetic torque oscillations occur at two times the supply voltage frequency. The objectives of this work are to quantify wind turbine structural loads induced...... by unbalanced voltage faults relative to those during normal operation; and to evaluate the potential for reducing structural loads with the control of the generator. The method applied is integrated dynamic analysis. Namely, dynamic analysis with models that consider the most important aeroelastic, electrical...

  10. Advancing marine hydrokinetic turbine arrays towards large-scale deployments in sandy rivers: a laboratory study

    Science.gov (United States)

    Musa, Mirko; Hill, Craig; Guala, Michele

    2016-11-01

    A staggered array of twelve axial-flow marine hydrokinetic (MHK) turbine models was investigated at the St. Anthony Falls Laboratory under live-bed sediment transport conditions. In particular, the interaction between the MHK power plant and the complex migrating bedforms was monitored using a state-of-the-art high-resolution submersible laser scanning device able to provide spatio(x,y)-temporally(t) resolved channel bathymetry z(x,y,t). Results revealed both a local signature of each individual turbine and a cumulative array effect that extends farther from the site. Single turbine localized scour results from the blockage effect of the operating rotor and the consequent flow acceleration between the lower rotor tip and the erodible bed. The resultant shear stress enhancement around the device protects the turbine during extreme sediment transport conditions, ultimately preventing the blades from impacting the incoming bedforms. A turbine failure case was simulated to illustrate the consequence of such event, which can irreversibly bury and damage the turbine. Additionally, velocity and turbine performance estimates provided a preliminary description of the power plant energy output, revealing similar features already observed in experimental wind farm models. NSF Career Grant - Geophysical Flow Control, Dr. Michele Guala.

  11. Study on the abnormal data rejection and normal condition evaluation applied in wind turbine farm

    Science.gov (United States)

    Zhang, Ying; Qian, Zheng; Tian, Shuangshu

    2016-01-01

    The condition detection of wind turbine is always an important issue which attract more and more attentions because of the rapid development of wind farm. And the on-line data analysis is also difficult since a lot of measured data is collected. In this paper, the abnormal data rejection and normal condition evaluation of wind turbine is processed. At first, since there are large amounts of abnormal data in the normal operation of wind turbine, which is probably caused by fault, maintenance downtime, power-limited operation and failure of wind speed sensor, a novel method is proposed to reject abnormal data in order to make more accurate analysis for the wind turbine condition. The core principle of this method is to fit the wind power curves by using the scatter diagram. The data outside the area covered by wind power curves is the abnormal data. The calculation shows that the abnormal data is rejected effectively. After the rejection, the vibration signals of wind turbine bearing which is a critical component are analyzed and the relationship between the vibration characteristic value and the operating condition of wind turbine is discussed. It will provide powerful support for the accurate fault analysis of wind turbine.

  12. Experimental Study on the Effects of Winglets on the Wake of a Model Wind Turbine

    Science.gov (United States)

    Tobin, Nicolas; Hamed, Ali M.; Chamorro, Leonardo P.

    2015-11-01

    Wind tunnel particle image velocimetry was used to investigate the effects of winglets on the wake dynamics of a model wind turbine. The behavior of a turbine with downstream-facing winglets was compared with a turbine without winglets. The turbines were placed in a turbulent boundary layer that reached up to the hub height, allowing for investigation of behavior in both turbulent and uniform flow. The winglets did not significantly change the strength of the tip vortices in the region of uniform incoming flow. The tip vortices in the more turbulent region, however, decayed much faster, diminishing to near-zero within the first ~1.5 rotor diameters, whereas the upper tip vortices persisted potentially up to ~4 rotor diameters. The winglets also increased the power coefficient by 7.5 %, while increasing the coefficient of thrust by 10.0 %. The higher coefficient of thrust created a region of enhanced mean shear in the outer portion of the wake, leading to increased turbulence statistics in the far wake. The wingletted turbine had a similar wake deficit at 5 rotor diameters as the base turbine did at 1.5 rotor diameters, with potential implications for using wingletted turbines in wind farms.

  13. Experimental Study on Influence of Pitch Motion on the Wake of a Floating Wind Turbine Model

    Directory of Open Access Journals (Sweden)

    Stanislav Rockel

    2014-03-01

    Full Text Available Wind tunnel experiments were performed, where the development of the wake of a model wind turbine was measured using stereo Particle Image Velocimetry to observe the influence of platform pitch motion. The wakes of a classical bottom fixed turbine and a streamwise oscillating turbine are compared. Results indicate that platform pitch creates an upward shift in all components of the flow and their fluctuations. The vertical flow created by the pitch motion as well as the reduced entrainment of kinetic energy from undisturbed flows above the turbine result in potentially higher loads and less available kinetic energy for a downwind turbine. Experimental results are compared with four wake models. The wake models employed are consistent with experimental results in describing the shapes and magnitudes of the streamwise velocity component of the wake for a fixed turbine. Inconsistencies between the model predictions and experimental results arise in the floating case particularly regarding the vertical displacement of the velocity components of the flow. Furthermore, it is found that the additional degrees of freedom of a floating wind turbine add to the complexity of the wake aerodynamics and improved wake models are needed, considering vertical flows and displacements due to pitch motion.

  14. Wind turbine wake interactions at field scale: An LES study of the SWiFT facility

    International Nuclear Information System (INIS)

    Yang, Xiaolei; Boomsma, Aaron; Sotiropoulos, Fotis; Barone, Matthew

    2014-01-01

    The University of Minnesota Virtual Wind Simulator (VWiS) code is employed to simulate turbine/atmosphere interactions in the Scaled Wind Farm Technology (SWiFT) facility developed by Sandia National Laboratories in Lubbock, TX, USA. The facility presently consists of three turbines and the simulations consider the case of wind blowing from South such that two turbines are in the free stream and the third turbine in the direct wake of one upstream turbine with separation of 5 rotor diameters. Large-eddy simulation (LES) on two successively finer grids is carried out to examine the sensitivity of the computed solutions to grid refinement. It is found that the details of the break-up of the tip vortices into small-scale turbulence structures can only be resolved on the finer grid. It is also shown that the power coefficient C P of the downwind turbine predicted on the coarse grid is somewhat higher than that obtained on the fine mesh. On the other hand, the rms (root-mean-square) of the C P fluctuations are nearly the same on both grids, although more small-scale turbulence structures are resolved upwind of the downwind turbine on the finer grid

  15. Structural Health Monitoring challenges on the 10-MW offshore wind turbine model

    Science.gov (United States)

    Di Lorenzo, E.; Kosova, G.; Musella, U.; Manzato, S.; Peeters, B.; Marulo, F.; Desmet, W.

    2015-07-01

    The real-time structural damage detection on large slender structures has one of its main application on offshore Horizontal Axis Wind Turbines (HAWT). The renewable energy market is continuously pushing the wind turbine sizes and performances. This is the reason why nowadays offshore wind turbines concepts are going toward a 10 MW reference wind turbine model. The aim of the work is to perform operational analyses on the 10-MW reference wind turbine finite element model using an aeroelastic code in order to obtain long-time-low- cost simulations. The aeroelastic code allows simulating the damages in several ways: by reducing the edgewise/flapwise blades stiffness, by adding lumped masses or considering a progressive mass addiction (i.e. ice on the blades). The damage detection is then performed by means of Operational Modal Analysis (OMA) techniques. Virtual accelerometers are placed in order to simulate real measurements and to estimate the modal parameters. The feasibility of a robust damage detection on the model has been performed on the HAWT model in parked conditions. The situation is much more complicated in case of operating wind turbines because the time periodicity of the structure need to be taken into account. Several algorithms have been implemented and tested in the simulation environment. They are needed in order to carry on a damage detection simulation campaign and develop a feasible real-time damage detection method. In addition to these algorithms, harmonic removal tools are needed in order to dispose of the harmonics due to the rotation.

  16. Operation and Equivalent Loads of Wind Turbines in Large Wind Farms

    Science.gov (United States)

    Andersen, Soren Juhl; Sorensen, Jens Norkaer; Mikkelsen, Robert Flemming

    2017-11-01

    Wind farms continue to grow in size and as the technology matures, the design of wind farms move towards including dynamic effects besides merely annual power production estimates. The unsteady operation of wind turbines in large wind farms has been modelled with EllipSys3D(Michelsen, 1992, and Sørensen, 1995) for a number of different scenarios using a fully coupled large eddy simulations(LES) and aero-elastic framework. The turbines are represented in the flow fields using the actuator line method(Sørensen and Shen, 2002), where the aerodynamic forces and deflections are derived from an aero-elastic code, Flex5(Øye, 1996). The simulations constitute a database of full turbine operation in terms of both production and loads for various wind speeds, turbulence intensities, and turbine spacings. The operating conditions are examined in terms of averaged power production and thrust force, as well as 10min equivalent flapwise bending, yaw, and tilt moment loads. The analyses focus on how the performance and loads change throughout a given farm as well as comparing how various input parameters affect the operation and loads of the wind turbines during different scenarios. COMWIND(Grant 2104-09- 067216/DSF), Nordic Consortium on Optimization and Control of Wind Farms, Eurotech Greentech Wind project, Winds2Loads, and CCA LES. Ressources Granted on SNIC and JESS. The Vestas NM80 turbine has been used.

  17. Model Reduction of Nonlinear Aeroelastic Systems Experiencing Hopf Bifurcation

    KAUST Repository

    Abdelkefi, Abdessattar

    2013-06-18

    In this paper, we employ the normal form to derive a reduced - order model that reproduces nonlinear dynamical behavior of aeroelastic systems that undergo Hopf bifurcation. As an example, we consider a rigid two - dimensional airfoil that is supported by nonlinear springs in the pitch and plunge directions and subjected to nonlinear aerodynamic loads. We apply the center manifold theorem on the governing equations to derive its normal form that constitutes a simplified representation of the aeroelastic sys tem near flutter onset (manifestation of Hopf bifurcation). Then, we use the normal form to identify a self - excited oscillator governed by a time - delay ordinary differential equation that approximates the dynamical behavior while reducing the dimension of the original system. Results obtained from this oscillator show a great capability to predict properly limit cycle oscillations that take place beyond and above flutter as compared with the original aeroelastic system.

  18. Aeroelastic Tailoring of a Plate Wing with Functionally Graded Materials

    Science.gov (United States)

    Dunning, Peter D.; Stanford, Bret K.; Kim, H. Alicia; Jutte, Christine V.

    2014-01-01

    This work explores the use of functionally graded materials for the aeroelastic tailoring of a metallic cantilevered plate-like wing. Pareto trade-off curves between dynamic stability (flutter) and static aeroelastic stresses are obtained for a variety of grading strategies. A key comparison is between the effectiveness of material grading, geometric grading (i.e., plate thickness variations), and using both simultaneously. The introduction of material grading does, in some cases, improve the aeroelastic performance. This improvement, and the physical mechanism upon which it is based, depends on numerous factors: the two sets of metallic material parameters used for grading, the sweep of the plate, the aspect ratio of the plate, and whether the material is graded continuously or discretely.

  19. Aeroelastic Flutter of Subsonic Aircraft Wing Section with Control Surface

    Directory of Open Access Journals (Sweden)

    Aeroelastic Flutter of Subsonic Aircraft Wing Section with Control Surface

    2015-12-01

    Full Text Available Aeroelastic flutter in aircraft mechanisms is unavoidable, essentially in the wing and control surface. In this work a three degree-of-freedom aeroelastic wing section with trailing edge flap is modeled numerically and theoretically. FLUENT code based on the steady finite volume is used for the prediction of the steady aerodynamic characteristics (lift, drag, pitching moment, velocity, and pressure distribution as well as the Duhamel formulation is used to model the aerodynamic loads theoretically. The system response (pitch, flap pitch and plunge was determined by integration the governing equations using MATLAB with a standard Runge–Kutta algorithm in conjunction with Henon’s method. The results are compared with previous experimental data. The results show that the aerodynamic loads and wing-flap system response are increased when increasing the flow speed. On the other hand the aeroelastic response led up to limit cycle oscillation when the flow equals or more than flutter speed.

  20. Experimental study of cyclone combustion of wood powder for gas turbine applications

    Energy Technology Data Exchange (ETDEWEB)

    Fredriksson, J.; Kallner, P. [Royal Inst. of Tech., Stockholm (Sweden). Dept. of Energy Technology

    1993-12-31

    The objective of the present project is to study to what extent various elements in the ash, in particular Na and K, can be separated in the first stage of a two-stage combustor, with the first stage being a separation cyclone. Mass balances for the elements in the ash are determined from the fuel flow, the char collected from the cyclone bottom and particles in the combustor outlet gas. Experiments have been carried out at atmospheric pressure for wood powder feeding rates of 5-21 kg/h. The conditions in the cyclone have been kept fuel rich. The gas outlet temperature from this stage has been varied from 750 to 1150 deg C through control of the air/fuel ratio. Second stage combustion is achieved in a separate combustor. The results show that significant separation of Na and K is possible, and that the separation is improved when the cyclone temperature is kept low. At an outlet temperature of around 800 deg C about 60% of the input alkali is found in the char residue. At 1000 deg C, only 30% is separated. Mass balances show that about 80% of the ash elements in the fuel input are identified in char and fly ash. With 60% separation of Na and K the content of these elements in the gas would be less than 7 mg/kg gas for a turbine inlet temperature of 850 deg C. The total dust load would be 30-60 mg/kg gas. Ash sticking temperature tests on bottom char and fly ash show no ash sticking up to 1040 deg C. It is therefore concluded that the ash may pass through the turbine as solid particles and cause minimal deposits or corrosion. 15 refs

  1. Laboratory Studies of the Effects of Pressure and Dissolved Gas Supersaturation on Turbine-Passed Fish

    Energy Technology Data Exchange (ETDEWEB)

    Neitzel, Duane A.

    2009-09-14

    Migratory and resident fish in the Columbia River Basin are exposed to stresses associated with hydroelectric power production, including changes in pressure as they pass through turbines and dissolved gas supersaturation (resulting from the release of water from the spillway). To examine pressure changes as a source of turbine-passage injury and mortality, Pacific Northwest National Laboratory scientists conducted specific tests using a hyperbaric chamber. Tests were designed to simulate Kaplan turbine passage conditions and to quantify the response of fish to rapid pressure changes, with and without the complication of fish being acclimated to gas-supersaturated water.

  2. Numerical Study of Wind Turbine Wake Modeling Based on a Actuator Surface Model

    DEFF Research Database (Denmark)

    Zhou, Huai-yang; Xu, Chang; Han, Xing Xing

    2017-01-01

    on the basis of actuator line model(ALM). By using ASM, the model of turbine can be simplified and the quantity of grids and computing time can be significantly reduced. A linear distribution model and a ASM Grid identification method are presented. This paper compares the ASM with ALM by computing both near...... and far wake of a Nibe A wind turbine, which combines wake velocity, turbulent intensity and vortex structure. Results show that ASM has better prediction accuracy and verify it's feasibility on numerical simulation of wind turbine wake....

  3. Environmental impact assessment study: Becancour gas turbine plant (Gentilly-2 nuclear site)

    International Nuclear Information System (INIS)

    Anon.

    1993-01-01

    The issue of ambient air quality is examined with respect to the atmospheric emissions from the Becancour gas turbine plant, a 350 MW peaking industrial type single cycle gas turbine plant. The plant is located adjacent to the Gentilly-2 nuclear plant. Project potential impacts, Quebec standards, ambient air quality, gas turbine plant contribution, atmospheric emissions cumulative impact, impacts on population health, sulfur dioxide and nitrogen oxide emissions, polycyclic aromatic hydrocarbons emissions, acid deposition, public opinion issues, and plant building and commissioning are discussed. A four station ambient air quality sampling network was implemented to assure environmental air quality in the vicinity of the plant. 4 tabs

  4. Thermoeconomic Modeling and Parametric Study of Hybrid Solid Oxide Fuel Cell â Gas Turbine â Steam Turbine Power Plants Ranging from 1.5 MWe to 10 MWe

    OpenAIRE

    Arsalis, Alexandros

    2007-01-01

    Detailed thermodynamic, kinetic, geometric, and cost models are developed, implemented, and validated for the synthesis/design and operational analysis of hybrid solid oxide fuel cell (SOFC) â gas turbine (GT) â steam turbine (ST) systems ranging in size from 1.5 MWe to 10 MWe. The fuel cell model used in this thesis is based on a tubular Siemens-Westinghouse-type SOFC, which is integrated with a gas turbine and a heat recovery steam generator (HRSG) integrated in turn with a steam turbi...

  5. Gas turbines

    Energy Technology Data Exchange (ETDEWEB)

    Farahan, E.; Eudaly, J.P.

    1978-10-01

    This evaluation provides performance and cost data for commercially available simple- and regenerative-cycle gas turbines. Intercooled, reheat, and compound cycles are discussed from theoretical basis only, because actual units are not currently available, except on a special-order basis. Performance characteristics investigated include unit efficiency at full-load and off-design conditions, and at rated capacity. Costs are tabulated for both simple- and regenerative-cycle gas turbines. The output capacity of the gas turbines investigated ranges from 80 to 134,000 hp for simple units and from 12,000 to 50,000 hp for regenerative units.

  6. Study on the behavior of moisture droplets in low pressure steam turbines

    International Nuclear Information System (INIS)

    Kimura, Y.; Kuramoto, Y.; Yoshida, K.; Etsu, M.

    1978-01-01

    Low pressure stages of fossil turbines and almost all stages of nuclear and geothermal turbines operate on wet steam. Turbine operating on wet steam have the following two disadvantages: decrease of efficiency and erosion of blades. Decrease of efficiency results from an increase in profile loss caused by water films on the blade surface; loss of steam energy in breaking up the films and accelerating moisture droplets; undercooling and condensation shocks associated with it; velocity difference between water and steam phases and consequent decelerating action of moisture droplets in the rotating blades, etc. Impingement of moisture droplets on the rotating blades also causes quick erosion of the blades. In this paper, the behavior of moisture droplets in wet steam flow is described and the correlation between their behavior and the abovementioned two disadvantages of turbines operating on wet steam is clarified. (author)

  7. Integrated aeroelastic vibrator for fluid mixing in open microwells

    Science.gov (United States)

    Xia, H. M.; Jin, X.; Zhang, Y. Y.; Wu, J. W.; Zhang, J.; Wang, Z. P.

    2018-01-01

    Fluid mixing in micro-wells/chambers is required in a variety of biological and biochemical processes. However, mixing fluids of small volumes is usually difficult due to increased viscous effects. In this study, we propose a new method for mixing enhancement in microliter-scale open wells. A thin elastic diaphragm is used to seal the bottom of the mixing microwell, underneath which an air chamber connects an aeroelastic vibrator. Driven by an air flow, the vibrator produces self-excited vibrations and causes pressure oscillations in the air chamber. Then the elastic diaphragm is actuated to mix the fluids in the microwell. Two designs that respectively have one single well and 2  ×  2 wells were prototyped. Testing results show that for liquids with a volume ranging from 10-60 µl and viscosity ranging from 1-5 cP, complete mixing can be obtained within 5-20 s. Furthermore, the device is operable with an air micropump, and hence facilitating the miniaturization and integration of lab-on-a-chip and microbioreactor systems.

  8. Performance and Potential Study of 10kW Wind Turbine Generator for 6 Cities in Malaysia

    Directory of Open Access Journals (Sweden)

    Mustaqimah Mustaqimah

    2013-04-01

    Full Text Available ABSTRACT. This study presents an analysis of the optimization by using HOMER software and financial viability of 10 kW wind turbine generator (WTG through grid connected system for six different locations in Malaysia (Mersing, Kuching, K.Trengganu, Kudat, Melaka and Labuan. Assessment criteria comprised Total Net Present Cost (TNPC, and Cost of Energy ( COE . The HOMER ( National Renewable Energy laboratory, US was utilized as the assessment tool with modeling performed with hourly load data input from six cities in Malaysia. The results demonstrate that WTG has the potential to supply significant power for small scale load in conjunction with the grid-electricity supply. Optimization modeling demonstrated that the TNPC for grid connected configuration is Mersing for the lowest TNPC among the other cities which is TNPC recorded at $ -28,436 and initial cost is about $ 20,000. This mean wind grid system in Mersing is very benefit be built and reduction in greenhouse gas emission of 9,452 kg/yr. Optimization modeling also showed that Mersing is the only one among other city had showed a high potential of WTG which produced energy at 85,326 kWh/yr and purchase grid only at 4,082 kWh/year. Kajian Kinerja dan Potensi Generator Turbin Angin 10kW untuk 6 kota di Malaysia ABSTRAK. Penelitian ini menyajikan analisis optimasi dengan menggunakan software HOMER dan kesesuaian biaya untuk generator turbin angin (wind turbine generator=WTG 10 kW sistem grid untuk enam lokasi yang berbeda di Malaysia (Mersing, Kuching, K.Trengganu, Kudat, Melaka dan Labuan. Kriteria penilaian terdiri Total Net Present Cost (TNPC dan Cost of Energy (COE. software HOMER (National Renewable Energy laboratory, US digunakan sebagai pemodelan dengan memasukkan data beban daya per jam dari enam kota tersebut. Hasil penelitian menunjukkan bahwa generator turbin angin (WTG memiliki potensi untuk memasok daya yang signifikan untuk beban kecil dalam hubungannya dengan pasokan grid

  9. Small Wind Turbine Technology Assessment

    International Nuclear Information System (INIS)

    Avia Aranda, F.; Cruz Cruz, I.

    1999-01-01

    The result of the study carried out under the scope of the ATYCA project Test Plant of Wind Systems for Isolated Applications, about the state of art of the small wind turbine technology (wind turbines with swept area smaller than 40 m 2 ) is presented. The study analyzes the collected information on 60 models of wind turbines from 23 manufacturers in the worldwide market. Data from Chinese manufacturers, that have a large participation in the total number of small wind turbines in operation, are not included, due to the unavailability of the technical information. (Author) 15 refs

  10. IEA Annex XX. Comparison between calculations and measurements on a wind turbine in yaw in the NASA-Ames wind tunnel

    Energy Technology Data Exchange (ETDEWEB)

    Schepers, J.G. [ECN Wind Energy, Petten (Netherlands)

    2007-10-15

    This report describes a study in which calculational results from ECN's aeroelastic code PHATAS and the free wake lifting line code AWSM are compared with measurements which were performed by NREL (National Renewable Energy Laboratory) on a wind turbine, placed in the large NASA-Ames wind tunnel. Measurements have been taken at a large variety of conditions but in this report only data at yawed conditions are considered. An important advantage of the present measurements is formed by the wind tunnel environment, which provides a very constant and homogeneous yaw angle and wind speed. The study was carried out within the framework IEA Annex XX 'Analysis of NASA-Ames wind tunnel measurements'.

  11. Pelton turbines

    CERN Document Server

    Zhang, Zhengji

    2016-01-01

    This book concerns the theoretical foundations of hydromechanics of Pelton turbines from the engineering viewpoint. For reference purposes, all relevant flow processes and hydraulic aspects in a Pelton turbine have been analyzed completely and systematically. The analyses especially include the quantification of all possible losses existing in the Pelton turbine and the indication of most available potential for further enhancing the system efficiency. As a guideline the book therefore supports further developments of Pelton turbines with regard to their hydraulic designs and optimizations. It is thus suitable for the development and design engineers as well as those working in the field of turbo machinery. Many laws described in the book can also be directly used to simplify aspects of computational fluid dynamics (CFD) or to develop new computational methods. The well-executed examples help better understand the related flow mechanics.

  12. Advanced turbine systems sensors and controls needs assessment study. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, R.L.; Fry, D.N.; McEvers, J.A.

    1997-02-01

    The Instrumentation and Controls Division of the Oak Ridge National Laboratory performed an assessment of the sensors and controls needs for land-based advanced gas turbines being designed as a part of the Department of Energy`s (DOE`s) Advanced Turbine Systems (ATS) Program for both utility and industrial applications. The assessment included visits to five turbine manufacturers. During these visits, in-depth discussions were held with design and manufacturing staff to obtain their views regarding the need for new sensors and controls for their advanced turbine designs. The Unsteady Combustion Facilities at the Morgantown Energy Technology Center was visited to assess the need for new sensors for gas turbine combustion research. Finally, a workshop was conducted at the South Carolina Energy Research and Development Center which provided a forum for industry, laboratory, and university engineers to discuss and prioritize sensor and control needs. The assessment identified more than 50 different measurement, control, and monitoring needs for advanced turbines that cannot currently be met from commercial sources. While all the identified needs are important, some are absolutely critical to the success of the ATS Program.

  13. Study on the application of energy storage system in offshore wind turbine with hydraulic transmission

    International Nuclear Information System (INIS)

    Fan, Yajun; Mu, Anle; Ma, Tao

    2016-01-01

    Highlights: • Hydraulic offshore wind turbine is capable of outputting near constant power. • Open loop hydraulic transmission uses seawater as the working fluid. • Linear control strategy distributes total flow according to demand and supply. • Constant pressure hydraulic accumulator stores/releases the surplus energy. • Simulations show the dynamic performance of the hybrid system. - Abstract: A novel offshore wind turbine comprising fluid power transmission and energy storage system is proposed. In this wind turbine, the conventional mechanical transmission is replaced by an open-loop hydraulic system, in which seawater is sucked through a variable displacement pump in nacelle connected directly with the rotor and utilized to drive a Pelton turbine installed on the floating platform. Aiming to smooth and stabilize the output power, an energy storage system with the capability of flexible charging and discharging is applied. The related mathematical model is developed, which contains some sub-models that are categorized as the wind turbine rotor, hydraulic pump, transmission pipeline, proportional valve, accumulator and hydraulic turbine. A linear control strategy is adopted to distribute the flow out of the proportional valve through comparing the demand power with captured wind energy by hydraulic pump. Ultimately, two time domain simulations demonstrate the operation of the hybrid system when the hydraulic accumulator is utilized and show how this system can be used for load leveling and stabilizing the output power.

  14. Study on the Wake of a Miniature Wind Turbine Using the Reynolds Stress Model

    Directory of Open Access Journals (Sweden)

    Jianxiao Hu

    2016-09-01

    Full Text Available The Reynolds Stress Model (RSM is adopted to simulate the wind turbine wake and the simulation results are compared with the wind tunnel test data, simulation results from the standard k-ε model and a modified k-ε model. RSM shows good performance in predicting the turbine wakes velocity, turbulence intensity and the kinetic shear stress, while the k-ε based models fail to predict either wakes velocity or turbulence intensity. Simulation results show that the wake velocity will be recovered up to 90% at around 10 D downstream of the turbine (D denotes turbine rotor diameter and it stops at 91% at around 16 D downstream. The wake turbulence intensity reaches a maximum at around 5 D downstream of turbine. Further investigation shows that the horizontal profile of the wakes velocity can be approximated by a Gaussian distribution, and the turbulence intensity can be approximated by a bimodal distribution. The influence of the wakes effect is limited to within ±D in the across-wind direction. The turbine wakes show clear anisotropy, which could explain the incorrect estimation on the turbulence intensity with the extended k-ε model.

  15. Probabilistic Design of Wind Turbine Structures: Design Studies and Sensitivities to Model Parameters

    DEFF Research Database (Denmark)

    NJOMO WANDJI, Wilfried

    Several societies have envisaged renewables as sources of energy for ecological and geo-strategical considerations. Amongst others, wind energy has gained considerable interest in the past decades due to its high potential to fulfil the aspirations of the societies that opted for it. However......, harnessing offshore wind energy poses challenges such as cost of energy reduction, handling of very large structures, randomness pertaining to the metocean environment, and need for better understanding of the mechanical behavior of the structures. Three means are employed in this thesis for cost reduction...... of braces based on the application of magneto-rheological dampers. Modelling methods and effectiveness are presented together with installation steps. The third employs an aero-elastically tailored rotor to alleviate fatigue loads on the support structure. Whereas the rotor optimization process was not done...

  16. Computational study of a High Pressure Turbine Nozzle/Blade Interaction

    Science.gov (United States)

    Kopriva, James; Laskowski, Gregory; Sheikhi, Reza

    2015-11-01

    A downstream high pressure turbine blade has been designed for this study to be coupled with the upstream uncooled nozzle of Arts and Rouvroit [1992]. The computational domain is first held to a pitch-line section that includes no centrifugal forces (linear sliding-mesh). The stage geometry is intended to study the fundamental nozzle/blade interaction in a computationally cost efficient manner. Blade/Nozzle count of 2:1 is designed to maintain computational periodic boundary conditions for the coupled problem. Next the geometry is extended to a fully 3D domain with endwalls to understand the impact of secondary flow structures. A set of systematic computational studies are presented to understand the impact of turbulence on the nozzle and down-stream blade boundary layer development, resulting heat transfer, and downstream wake mixing in the absence of cooling. Doing so will provide a much better understanding of stage mixing losses and wall heat transfer which, in turn, can allow for improved engine performance. Computational studies are performed using WALE (Wale Adapted Local Eddy), IDDES (Improved Delayed Detached Eddy Simulation), SST (Shear Stress Transport) models in Fluent.

  17. STUDY ON DISCHARGE HEAT UTILIZATION OF 250 MWe PCMSR TURBINE SYSTEM FOR DESALINATION USING MODIFIED MED

    Directory of Open Access Journals (Sweden)

    Andang Widiharto

    2015-03-01

    Full Text Available PCMSR (Passive Compact Molten Salt Reactor is one type of Advanced Nuclear Reactors. The PCMSR has benefit charasteristics of very efficient fuel use, high safety charecteristic as well as high thermodinamics efficiency. This is due to its breeding capability, inherently safe characteristic and totally passive safety system. The PCMSR design consists of three module, i.e. reactor module, turbine module and fuel management module. Analysis in performed by parametric calculation of the turbine system to calculate the turbine system efficiency and the hat available for desalination. After that the mass and energi balance of desalination process are calculated to calculate the amount of distillate produced and the amount of feed sea water needed. The turbine module is designed to be operated at maximum temperature cycle of 1373 K (1200 0C and minimum temperature cycle of 333 K (60 0K. The parametric calculation shows that the optimum turbine pressure ratio is 4.3 that gives the conversion efficiency of 56 % for 4 stages turbine and 4 stages compressor and equiped with recuperator. In this optimum condition, the 250 MWe PCMSR turbine system produces 196 MWth of waste heat with the temperature of cooling fluid in the range from 327 K (54 0C to 368 K (92 0C. This waste heat can be utilized for desalination. By using MMED desalination system, this waste heat can be used to produce fresh water (distillate from sea water feed. The amount of the destillate produced is 48663 ton per day by using 15 distillation effects. The performance ratio value is 2.8727 kg/MJ by using 15 distillation effects. Keywords: PCMSR, discharged heat, MMED desalination   PCMSR (Passive Compact Molten Salt Reactor merupakan salah satu tipe dari Reaktor Nuklir Maju. PCMSR memiliki keuntungan berupa penggunaan bahan bakar yang sangat efisisien, sifat keselamatan tinggi dan sekaligus efisiensi termodinamika yang tinggi. Hal ini disebabkan oleh kemampuan pembiakan bahan bakar, sifat

  18. On Usage of Pareto curves to Select Wind Turbine Controller Tunings to the Wind Turbulence Level

    DEFF Research Database (Denmark)

    Odgaard, Peter Fogh

    2015-01-01

    Model predictive control has in recently publications shown its potential for lowering of cost of energy of modern wind turbines. Pareto curves can be used to evaluate performance of these controllers with multiple conflicting objectives of power and fatigue loads. In this paper an approach...... to update an model predictive wind turbine controller tuning as the wind turbulence increases, as increased turbulence levels results in higher loads for the same controller tuning. In this paper the Pareto curves are computed using an industrial high fidelity aero-elastic model. Simulations show...

  19. Tuned liquid column dampers for mitigation of edgewise vibrations in rotating wind turbine blades

    DEFF Research Database (Denmark)

    Zhang, Zili; Basu, Biswajit; Nielsen, Søren R.K.

    2015-01-01

    Edgewise vibrations in wind turbine blades are lightly damped, and large amplitude vibrations induced by the turbulence may significantly shorten the fatigue life of the blade. This paper investigates the performance of tuned liquid column dampers (TLCDs) for mitigating edgewise vibrations......, with the consideration of both the space limitation inside the blade and the constraint of the liquid motion. The edgewise modal load for the 2-DOF model has been calculated from a more sophisticated 13-DOF aeroelastic wind turbine model, which includes the coupling of the blade-tower-drivetrain vibration...

  20. Lumped-Parameter Models for Wind-Turbine Footings on Layered Ground

    DEFF Research Database (Denmark)

    Andersen, Lars; Liingaard, Morten

    2007-01-01

    The design of modern wind turbines is typically based on lifetime analyses using aeroelastic codes. In this regard, the impedance of the foundations must be described accurately without increasing the overall size of the computational model significantly. This may be obtained by the fitting...... of a lumped-parameter model to the results of a rigorous model or experimental results. In this paper, guidelines are given for the formulation of such lumped-parameter models and examples are given in which the models are utilised for the analysis of a wind turbine supported by a surface footing on a layered...

  1. Evaluation of damping estimates by automated Operational Modal Analysis for offshore wind turbine tower vibrations

    DEFF Research Database (Denmark)

    Bajrić, Anela; Høgsberg, Jan Becker; Rüdinger, Finn

    2018-01-01

    with a particular focus on damping estimation of wind turbine towers. In the design of offshore structures the estimates of damping are crucial for tuning of the numerical model. The errors of damping estimates are evaluated from simulated tower response of an aeroelastic model of an 8 MW offshorewind turbine...... techniques are discussed and illustrated with respect to signal noise, measurement time, vibration amplitudes and stationarity of the ambient response. The best bias-variance error trade-off of damping estimates is obtained by the COV-SSI. The proposed automated procedure is validated by real vibration...

  2. Parameter estimation of an aeroelastic aircraft using neural networks

    Indian Academy of Sciences (India)

    Application of neural networks to the problem of aerodynamic modelling and parameter estimation for aeroelastic aircraft is addressed. A neural model capable of predicting generalized force and moment coefficients using measured motion and control variables only, without any need for conventional normal elastic ...

  3. Aeroelastic simulation using CFD based reduced order models

    International Nuclear Information System (INIS)

    Zhang, W.; Ye, Z.; Li, H.; Yang, Q.

    2005-01-01

    This paper aims at providing an accurate and efficient method for aeroelastic simulation. System identification is used to get the reduced order models of unsteady aerodynamics. Unsteady Euler codes are used to compute the output signals while 3211 multistep input signals are utilized. LS(Least Squares) method is used to estimate the coefficients of the input-output difference model. The reduced order models are then used in place of the unsteady CFD code for aeroelastic simulation. The aeroelastic equations are marched by an improved 4th order Runge-Kutta method that only needs to compute the aerodynamic loads one time at every time step. The computed results agree well with that of the direct coupling CFD/CSD methods. The computational efficiency is improved 1∼2 orders while still retaining the high accuracy. A standard aeroelastic computing example (isogai wing) with S type flutter boundary is computed and analyzed. It is due to the system has more than one neutral points at the Mach range of 0.875∼0.9. (author)

  4. Quasi-Static Condensation of Aeroelastic Suspension Bridge Model

    DEFF Research Database (Denmark)

    Møller, Randi N.; Krenk, Steen; N. Svendsen, Martin

    2017-01-01

    for turbulence when considering the stability limit and further it is not possible to account for non-linear effects. These limitations suggest to do simulations of the aeroelastic response of long span bridges in the time domain. For this it is of interest to have an efficient model while still maintaining...

  5. Aeroelastic Loads Modeling for Composite Aircraft Design Support

    NARCIS (Netherlands)

    Baluch, H.A.

    2009-01-01

    With regard to the simulation of structural vibrations and consequent aeroelastic loads in aircraft components, the use of elastic axis e.a as reference of vibrations is quite common. The e.a decouples the bending and torsion degrees of freedom (D.o.F) during the dynamic analysis. The use of the e.a

  6. Contribution to finite element modelling of airfoil aeroelastic instabilities

    Czech Academy of Sciences Publication Activity Database

    Horáček, Jaromír; Sváček, P.; Růžička, M.; Feistauer, M.

    2007-01-01

    Roč. 1, č. 1 (2007), s. 43-52 ISSN 1802-680X. [Computational Mechanics 2007. Hrad Nečtiny, 05.11.2007-07.11.2007] R&D Projects: GA MPO FT-TA/026 Institutional research plan: CEZ:AV0Z20760514 Keywords : induced vibration * aeroelasticity * nonlinear vibrations Subject RIV: BI - Acoustics

  7. Analysis of operational limit of an aircraft: An aeroelastic approach

    Science.gov (United States)

    Hasan, Md. Mehedi; Hassan, M. D. Mehedi; Sarrowar, S. M. Bayazid; Faisal, Kh. Md.; Ahmed, Sheikh Reaz, Dr.

    2017-06-01

    In classical theory of elasticity, external loading acting on the body is independent of deformation of the body. But, in aeroelasticity, aerodynamic forces depend on the attitude of the body relative to the flow. Aircraft's are subjected to a range of static loads resulting from equilibrium or steady flight maneuvers such as coordinated level turn, steady pitch and bank rate, steady and level flight. Interaction of these loads with elastic forces of aircraft structure creates some aeroelastic phenomena. In this paper, we have summarized recent developments in the area of aeroelasticity. A numerical approach has been applied for finding divergence speed, a static aeroelastic phenomena, of a typical aircraft. This paper also involves graphical representations of constraints on load factor and bank angle during different steady flight maneuvers taking flexibility into account and comparing it with the value without flexibility. Effect of wing skin thickness, spar web thickness and position of flexural axis of wing on this divergence speed as well as load factor and bank angle has also been observed using MATLAB.

  8. Aeroelastic Analysis of Modern Complex Wings Using ENSAERO and NASTRAN

    Science.gov (United States)

    Bhardwaj, Manoj

    1995-01-01

    A process is presented by which static aeroelastic analysis is performed using Euler flow equations in conjunction with an advanced structural analysis tool, NASTRAN. The process deals with the interfacing of two separate codes in the fields of computational fluid dynamics (CFD) and computational structural dynamics (CSD). The process is demonstrated successfully on an F/A-18 Stabilator (horizontal tail).

  9. Final Technical Report: Supporting Wind Turbine Research and Testing - Gearbox Durability Study

    Energy Technology Data Exchange (ETDEWEB)

    Matthew Malkin

    2012-04-30

    The combination of premature failure of wind turbine gearboxes and the downtime caused by those failures leads to an increase in the cost of electricity produced by the wind. There is a need for guidance to asset managers regarding how to maximize the longevity of their gearboxes in order to help keep the cost of wind energy as low as possible. A low cost of energy supports the US Department of Energy's goal of achieving 20% of the electricity in the United States produced by wind by the year 2030. DNV KEMA has leveraged our unique position in the industry as an independent third party engineering organization to study the problem of gearbox health management and develop guidance to project operators. This report describes the study. The study was conducted in four tasks. In Task 1, data that may be related to gearbox health and are normally available to wind project operators were collected for analysis. Task 2 took a more in-depth look at a small number of gearboxes to gain insight in to relevant failure modes. Task 3 brought together the previous tasks by evaluating the available data in an effort to identify data that could provide early indications of impending gearbox failure. Last, the observations from the work were collected to develop recommendations regarding gearbox health management.

  10. Study on Power Fluctuation Characteristics of Wind Energy Converters with Fluctuating Turbine Torque

    Science.gov (United States)

    Takata, Go; Katayama, Norihide; Miyake, Masatoshi; Nanahara, Toshiya

    In recent years, installed capacity of wind power generation has significantly increased in the countries including Japan. This increase gives rise to growing concerns on power quality of a power system with large penetration of wind power because fluctuation of its output power is significantly larger than that of conventional power sources. Tower shadow effects, the fluctuation frequency of which is determined by rotating speed of a wind turbine, considerably contribute to the fluctuation. While the power fluctuation due to tower shadow effects can cause flicker and thereby deteriorate power quality, its amplitude varies with constants of induction generators and impedance of the distribution/transmission system connected to the generators. This paper examines the relationship between the amplitude of the power fluctuation and input torque of an induction generator while making machine constants or back impedance at the connection point parameters. The study derives a transfer function describing the relationship by linearizing related differential equations and verifies its validity through a simulation study with MATLAB/Simulink. Implication of the results on amplitude of 3N components of wind power output is discussed.

  11. Optimization of turbine positioning in water distribution networks. A Sicilian case study

    Science.gov (United States)

    Milici, Barbara; Messineo, Simona; Messineo, Antonio

    2017-11-01

    The potential energy of water in Water Distribution Networks (WDNs), is usually dissipated by Pressure Reduction Valves (PRVs), thanks to which water utilities manage the pressure level in selected nodes of the network. The present study explores the use of economic hydraulic machines, pumps as turbines (PATs), to produce energy in a small network with the aim to avoid dissipation in favour of renewable energy production. The proposed study is applied to a WDN located in a town close to Palermo (Sicily), where users often install private tanks, to collect water during the period of water scarcity conditions. As expected, the economic benefit of PATs installation in WDNs is affected by the presence of private tanks, whose presence deeply modifies the network from designed condition. The analysis is carried out by means of a mathematical model, which is able to simulate dynamically water distribution networks with private tanks and PATs. As expected, the advantage of PATs' installation in terms of renewable energy recovery is strictly conditioned by their placement in the WDN.

  12. Computational fluid dynamics as surgical planning tool: a pilot study on middle turbinate resection.

    Science.gov (United States)

    Zhao, Kai; Malhotra, Prashant; Rosen, David; Dalton, Pamela; Pribitkin, Edmund A

    2014-11-01

    Controversies exist regarding the resection or preservation of the middle turbinate (MT) during functional endoscopic sinus surgery. Any MT resection will perturb nasal airflow and may affect the mucociliary dynamics of the osteomeatal complex. Neither rhinometry nor computed tomography (CT) can adequately quantify nasal airflow pattern changes following surgery. This study explores the feasibility of assessing changes in nasal airflow dynamics following partial MT resection using computational fluid dynamics (CFD) techniques. We retrospectively converted the pre- and postoperative CT scans of a patient who underwent isolated partial MT concha bullosa resection into anatomically accurate three-dimensional numerical nasal models. Pre- and postsurgery nasal airflow simulations showed that the partial MT resection resulted in a shift of regional airflow towards the area of MT removal with a resultant decreased airflow velocity, decreased wall shear stress and increased local air pressure. However, the resection did not strongly affect the overall nasal airflow patterns, flow distributions in other areas of the nose, nor the odorant uptake rate to the olfactory cleft mucosa. Moreover, CFD predicted the patient's failure to perceive an improvement in his unilateral nasal obstruction following surgery. Accordingly, CFD techniques can be used to predict changes in nasal airflow dynamics following partial MT resection. However, the functional implications of this analysis await further clinical studies. Nevertheless, such techniques may potentially provide a quantitative evaluation of surgical effectiveness and may prove useful in preoperatively modeling the effects of surgical interventions. © 2014 Wiley Periodicals, Inc.

  13. Study of damage and repair of blades of a 300 kW wind turbine

    Energy Technology Data Exchange (ETDEWEB)

    Marin, J.C.; Barroso, A.; Paris, F.; Canas, J. [School of Engineering, University of Seville, Camino de los Descubrimientos s/n, 41092 Seville (Spain)

    2008-07-15

    The inspection of damages detected in some blades of 300 kW wind turbines revealed that the nature of these damages was probably due to a fatigue mechanism. The causes that had originated the failure (superficial cracks, geometric concentrator, abrupt change of thickness) have been studied, verifying, by means of the simplified evaluation procedure of fatigue life of the ''Germanischer Lloyd'' (GL) standard, that these causes can explain the failure detected in the period of time in which it happened. A suitable configuration for the repair of the damaged blades has been studied, by means of a finite element model. The proposed modifications repair the cracks and in addition contribute to relaxing the stress state in the affected zone. The introduction of a triangular reinforcement, which smoothes the re-entrant corner existing in the original design, incorporating a laminate of reinforcement, produces a significant decrease in the stress level in the damaged zone of the blades. (author)

  14. Three-dimensional modelling for assessment of far-field impact of tidal stream turbine: A case study at the Anglesey Coast, Wales, UK

    Science.gov (United States)

    Li, Xiaorong; Li, Ming; Wolf, Judith

    2017-04-01

    As a response to worldwide climate change, clean non-carbon renewable energy resources have been gaining significant attention. Among a range of renewable alternatives, tidal stream energy is considered very promising; due to its consistent predictability and availability. To investigate impacts of tidal stream devices on their surroundings, prototype experiments involving small scale laboratory studies have been implemented. Computational Flow Dynamics (CFD) modelling is also commonly applied to study turbine behaviours. However, these studies focus on impacts of the turbine in the near-field scale. As a result, in order to study and predict the far-field impacts caused by the operation of turbines, large scale 2D and 3D numerical oceanography models have been used, with routines added to reflect the impacts of turbines. In comparison to 2D models, 3D models are advantageous in providing complete prediction of vertical flow structures and hence mixing in the wake of a turbine. This research aims to deliver a thorough 3D tidal stream turbine simulation system, by considering major coastal processes, i.e. current, waves and sediment transport, based on a 3D wave-current-sediment fully coupled numerical oceanography model — the Unstructured Grid Finite Volume Community Ocean Model (FVCOM). The energy extraction of turbines is simulated by adding a body force to the momentum equations. Across the water depth, the coefficient related to the additional body force is given different values according to the turbine configuration and operation to reflect the vertical variation of the turbine's impacts on the passing flow. Three turbulence perturbation terms are added to the turbulence closure to simulate the turbine-induced turbulence generation, dissipation and interference for the turbulence length-scale. Impacts of turbine operation on surface waves are also considered by modification of wave energy flux across the device. A thorough validation study is carried out in

  15. Energy Conversion Alternatives Study (ECAS), Westinghouse phase 1. Volume 6: Closed-cycle gas turbine systems. [energy conversion efficiency in electric power plants

    Science.gov (United States)

    Amos, D. J.; Fentress, W. K.; Stahl, W. F.

    1976-01-01

    Both recuperated and bottomed closed cycle gas turbine systems in electric power plants were studied. All systems used a pressurizing gas turbine coupled with a pressurized furnace to heat the helium for the closed cycle gas turbine. Steam and organic vapors are used as Rankine bottoming fluids. Although plant efficiencies of over 40% are calculated for some plants, the resultant cost of electricity was found to be 8.75 mills/MJ (31.5 mills/kWh). These plants do not appear practical for coal or oil fired plants.

  16. Anisotropic beam model for analysis and design of passive controlled wind turbine blades

    Energy Technology Data Exchange (ETDEWEB)

    Branner, K.; Blasques, J.P.; Kim, T.; Fedorov, V.A.; Berring, P.; Bitsche, R.D.; Berggreen, C.

    2012-02-15

    The main objective of the project was, through theoretical and experimental research, to develop and validate a fully coupled, general beam element that can be used for advanced and rapid analysis of wind turbine blades. This is fully achieved in the project and the beam element has even been implemented in the aeroelastic code HAWC2. It has also been demonstrated through a parametric study in the project that a promising possibility with the tool is to reduce fatigue loads through structural couplings. More work is needed before these possibilities are fully explored and blades with structural couplings can be put into production. A cross section analysis tool BECAS (BEam Cross section Analysis Software) has been developed and validated in the project. BECAS is able to predict all geometrical and material induced couplings. This tool has obtained great interest from both industry and academia. The developed fully coupled beam element and cross section analysis tool has been validated against both numerical calculations and experimental measurements. Numerical validation has been performed against beam type calculations including Variational Asymptotical Beam Section Analysis (VABS) and detailed shell and solid finite element analyses. Experimental validation included specially designed beams with built-in couplings, a full-scale blade section originally without couplings, which subsequently was modified with extra composite layers in order to obtain measurable couplings. Both static testing and dynamic modal analysis tests have been performed. The results from the project now make it possible to use structural couplings in an intelligent manner for the design of future wind turbine blades. The developed beam element is especially developed for wind turbine blades and can be used for modeling blades with initial curvature (pre-bending), initial twist and taper. Finally, it have been studied what size of structural couplings can be obtained in current and future

  17. Byers Auto Group: A Case Study Into The Economics, Zoning, and Overall Process of Installing Small Wind Turbines at Two Automotive Dealerships in Ohio

    Energy Technology Data Exchange (ETDEWEB)

    Oteri, F.; Sinclair, K.

    2011-11-01

    This paper provides the talking points about a case study on the installation of a $600,000 small wind project, the installation process, estimated annual energy production and percentage of energy needs met by the turbines.

  18. Aeroelastic Tailoring of the NASA Common Research Model via Novel Material and Structural Configurations

    Science.gov (United States)

    Jutte, Christine V.; Stanford, Bret K.; Wieseman, Carol D.; Moore, James B.

    2014-01-01

    This work explores the use of tow steered composite laminates, functionally graded metals (FGM), thickness distributions, and curvilinear rib/spar/stringer topologies for aeroelastic tailoring. Parameterized models of the Common Research Model (CRM) wing box have been developed for passive aeroelastic tailoring trade studies. Metrics of interest include the wing weight, the onset of dynamic flutter, and the static aeroelastic stresses. Compared to a baseline structure, the lowest aggregate static wing stresses could be obtained with tow steered skins (47% improvement), and many of these designs could reduce weight as well (up to 14%). For these structures, the trade-off between flutter speed and weight is generally strong, although one case showed both a 100% flutter improvement and a 3.5% weight reduction. Material grading showed no benefit in the skins, but moderate flutter speed improvements (with no weight or stress increase) could be obtained by grading the spars (4.8%) or ribs (3.2%), where the best flutter results were obtained by grading both thickness and material. For the topology work, large weight reductions were obtained by removing an inner spar, and performance was maintained by shifting stringers forward and/or using curvilinear ribs: 5.6% weight reduction, a 13.9% improvement in flutter speed, but a 3.0% increase in stress levels. Flutter resistance was also maintained using straightrotated ribs although the design had a 4.2% lower flutter speed than the curved ribs of similar weight and stress levels were higher. These results will guide the development of a future design optimization scheme established to exploit and combine the individual attributes of these technologies.

  19. Low Wind Speed Turbine Project Conceptual Design Study: Advanced Independent Pitch Control; July 30, 2002--July 31, 2004 (Revised)

    Energy Technology Data Exchange (ETDEWEB)

    Olsen, T.; Lang, E.; Hansen, A.C.; Cheney, M. C.; Quandt, G.; VandenBosche, J.; Meyer, T.

    2004-12-01

    AES conducted a conceptual study of independent pitch control using inflow angle sensors. The control strategy combined input from turbine states (rotor speed, rotor azimuth, each blade pitch) with inflow angle measurements (each blade angle of attack at station 11 of 15) to derive blade pitch demand signals. The controller reduced loads sufficiently to allow a 10% rotor extension and reduce COE by 6.3%.

  20. Performance and Potential Study of 10kW Wind Turbine Generator for 6 Cities in Malaysia

    OpenAIRE

    Mustaqimah Mustaqimah

    2013-01-01

    ABSTRACT. This study presents an analysis of the optimization by using HOMER software and financial viability of 10 kW wind turbine generator (WTG) through grid connected system for six different locations in Malaysia (Mersing, Kuching, K.Trengganu, Kudat, Melaka and Labuan). Assessment criteria comprised Total Net Present Cost (TNPC), and Cost of Energy ( COE ). The HOMER ( National Renewable Energy laboratory, US) was utilized as the assessment tool with modeling performed with hourly load ...

  1. Generation Risk Assessment Using Fault Trees and Turbine Cycle Simulation: Case Studies

    International Nuclear Information System (INIS)

    Heo, Gyun Young; Park, Jin Kyun

    2009-01-01

    Since 2007, Korea Atomic Energy Research Institute and Kyung Hee University have collaborated on the development of the framework to quantify human errors broken out during the test and maintenance (T and M) in secondary systems of nuclear power plants (NPPs). The project entitled 'Development of Causality Analyzer for Maintenance/Test Tasks in Nuclear Power Plants' for OPR1000 on the basis of the proposed framework is still on-going, and will come to fruition by 2010. The overall concept of GRA-HRE (Generation Risk Assessment for Human Related Events) which is the designation of the framework, and the quantification methods for evaluating risk and electric loss have introduced in other references. The originality emerged while implementing GRA-HRE could be evaluated in view of (1) recognizing the relative importance of human errors comparing with other types of mechanical and/or electrical failures, (2) providing the top-down path of the propagation of human errors by designating top events in the fault tree model as trip signals, and (3) analyzing electric loss using turbine cycle simulation. Recently, we were successfully to illustrate the applicability of GRA-HRE by simulating several abnormalities. Since the detailed methodologies were released enough to follow up, this paper is going to only exemplify the case studies

  2. A concept study of a carbon spar cap design for a 80m wind turbine blade

    International Nuclear Information System (INIS)

    Rosemeier, M; Bätge, M

    2014-01-01

    The buckling resistance is a key design driver for large wind turbine blades with a significant influence on the material costs. During the structural design process the choice was made for carbon spar caps and two shear webs, which were set relatively far apart in order to stabilize the panels. This design presented a major challenge for the stability of the spar caps. The topology of these spar caps has been modified with regard to stability, comparing a continuous spar cap with split spar cap concepts and considering both lay-ups with hybrid carbon glass spar caps or sandwich concepts. Within those concepts, parametric studies were conducted varying different geometrical parameters of the spar caps and its layups. In order to determine the buckling resistance of the spar cap, an analytical model considering a 2D cross section discretized blade model was utilized to select the basic concept, after which a 3D numerical finite element model taking the whole blade into account was used to evaluate the chosen design concepts. The stability limit state analysis was conducted according to the certification scheme of GL guideline 2012. The various concepts were evaluated based on the blade's mass, tip deflection and modal properties. The results of this design process of the spar caps and the evaluation of the used analysis tools are presented within the paper

  3. Thermodynamic Performance Study of Biomass Gasification, Solid Oxide Fuel Cell and Micro Gas Turbine Hybrid Systems

    DEFF Research Database (Denmark)

    Bang-Møller, Christian; Rokni, Masoud

    2010-01-01

    University of Denmark. The SOFC converts the syngas more efficiently than the MGT, which is reflected by the energetic electrical efficiency of the gasifier and MGT system in opposition to the gasifier and SOFC configuration – η_el = 28.1% versus η_el = 36.4%. By combining the SOFC and MGT, the unconverted......A system level modelling study of three combined heat and power systems based on biomass gasification is presented. Product gas is converted in a micro gas turbine (MGT) in the first system, in a solid oxide fuel cell (SOFC) in the second system and in a combined SOFC–MGT arrangement in the third...... system. An electrochemical model of the SOFC has been developed and calibrated against published data from Topsoe Fuel Cells A/S and the Risø National Laboratory. The modelled gasifier is based on an up scaled version (~500 kW_th) of the demonstrated low tar gasifier, Viking, situated at the Technical...

  4. A concept study of a carbon spar cap design for a 80m wind turbine blade

    Science.gov (United States)

    Rosemeier, M.; Bätge, M.

    2014-06-01

    The buckling resistance is a key design driver for large wind turbine blades with a significant influence on the material costs. During the structural design process the choice was made for carbon spar caps and two shear webs, which were set relatively far apart in order to stabilize the panels. This design presented a major challenge for the stability of the spar caps. The topology of these spar caps has been modified with regard to stability, comparing a continuous spar cap with split spar cap concepts and considering both lay-ups with hybrid carbon glass spar caps or sandwich concepts. Within those concepts, parametric studies were conducted varying different geometrical parameters of the spar caps and its layups. In order to determine the buckling resistance of the spar cap, an analytical model considering a 2D cross section discretized blade model was utilized to select the basic concept, after which a 3D numerical finite element model taking the whole blade into account was used to evaluate the chosen design concepts. The stability limit state analysis was conducted according to the certification scheme of GL guideline 2012. The various concepts were evaluated based on the blade's mass, tip deflection and modal properties. The results of this design process of the spar caps and the evaluation of the used analysis tools are presented within the paper.

  5. Next Generation Wind Turbine

    Energy Technology Data Exchange (ETDEWEB)

    Cheraghi, S. Hossein [Western New England Univ., Springfield, MA (United States); Madden, Frank [FloDesign Wind Turbine Corp., Waltham, MA (United States)

    2012-09-01

    The goal of this collaborative effort between Western New England University's College of Engineering and FloDesign Wind Turbine (FDWT) Corporation to wok on a novel areodynamic concept that could potentially lead to the next generation of wind turbines. Analytical studies and early scale model tests of FDWT's Mixer/Ejector Wind Turbine (MEWT) concept, which exploits jet-age advanced fluid dynamics, indicate that the concept has the potential to significantly reduce the cost of electricity over conventional Horizontal Axis Wind Turbines while reducing land usage. This project involved the design, fabrication, and wind tunnel testing of components of MEWT to provide the research and engineering data necessary to validate the design iterations and optimize system performance. Based on these tests, a scale model prototype called Briza was designed, fabricated, installed and tested on a portable tower to investigate and improve the design system in real world conditions. The results of these scale prototype efforts were very promising and have contributed significantly to FDWT's ongoing development of a product scale wind turbine for deployment in multiple locations around the U.S. This research was mutually beneficial to Western New England University, FDWT, and the DOE by utilizing over 30 student interns and a number of faculty in all efforts. It brought real-world wind turbine experience into the classroom to further enhance the Green Engineering Program at WNEU. It also provided on-the-job training to many students, improving their future employment opportunities, while also providing valuable information to further advance FDWT's mixer-ejector wind turbine technology, creating opportunities for future project innovation and job creation.

  6. Gearbox and Drivetrain Models to Study Dynamic Effects of Modern Wind Turbines: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Girsang, I. P.; Dhupia, J. S.; Muljadi, E.; Singh, M.; Pao, L. Y.

    2013-10-01

    Wind turbine drivetrains consist of components that directly convert kinetic energy from the wind to electrical energy. Guaranteeing robust and reliable drivetrain designs is therefore important to minimize turbine downtime. Current drivetrain models often lack the ability to model both the impacts of electrical transients as well as wind turbulence and shear in one package. In this work, thecapability of the FAST wind turbine computer-aided engineering tool, developed by the National Renewable Energy Laboratory, is enhanced through integration of a dynamic model of the drivetrain. The dynamic drivetrain model is built using Simscape in the MATLAB/Simulink environment and incorporates detailed electrical generator models. This model can be used in the future to test advanced controlschemes to extend life of the gearbox.

  7. Calculating Study of the Turbine at Last Stage Flow Field in the Small Volume Flow Condition

    Directory of Open Access Journals (Sweden)

    Jiang Tieliu

    2017-11-01

    Full Text Available Based on basic equation and boundary layer theory of pneumodynamics, the thesis conducts numerical modeling and theoretical analysis on the last stage of turbine characteristics at a small volume flow by using FLUENT, gives an emphasized analysis on the position of first occurrence of backflow and its expansion direction and comes up with flow structure of the turbine flow field at last stage in the small volume flow condition. In connection with specific experiments, it puts forward the flow model of backflow occurring in the last stage field and the solution to the model. The flow field at last stage for a 100MW turbine in the small volume flow condition that is calculated by using the model is basically in conformity to the actual result.

  8. Erosion study of final stage blading of low pressure steam turbines

    Science.gov (United States)

    Dehouve, J.; Nardin, P.; Zeghmati, M.

    1999-04-01

    In order to increase our knowledge of erosion phenomena, the Steam Turbine Groupe (STG) of ALSTOM has been using an erosion test facility in the C.R.T.V. (Centre de Recherche Turbines à Vapeur). This test facility simulates erosion in low pressure steam turbine cylinders in order to compare the erosion resistance of various blade materials (12% chromium steel, titanium alloys, etc.) and their protection (superficial hardening, coatings, etc.). This test facility also allows us to understand the mechanism causing damage at a macroscopic level (impact energy of the droplets and the loss of eroded volume) and at a microscopic level (residual stress and metallurgic analysis) and therefore to determine an evolution law of material surface damage. In this paper, the behaviour of the materials (12% chromium steel and titanium alloys), which has been analysed by image production measurement methods, will be presented according to different impact velocities.

  9. Subjective and objective parameters in the evaluation of radiofrequency ablation of the inferior turbinate do not correlate: A pilot study.

    Science.gov (United States)

    Tomazic, Peter Valentin; Gerstenberger, Claus; Rant, Bettina; Nemetz, Ulrike; Brezjak-Kahlert, Christiana; Wolf, Axel; Freudenschuss, Kurt; Wolf, Gerald

    2016-08-01

    Inferior turbinate hypertrophy is a common cause of nasal obstruction. We conducted a prospective study to correlate subjective and objective parameters in assessing the effectiveness of radiofrequency ablation (RFA). Our initial study population was made up of 10 patients who presented with nasal obstruction; 1 patient was lost to follow-up, leaving us with 7 women and 2 men, aged 26 to 65 years (mean: 37.9 ± 12.8), and 16 turbinates (7 bilateral, 1 right, and 1 left). Visual analogue scale (VAS) scores, Nasal Obstruction and Symptom Evaluation (NOSE) questionnaire scores, rhinomanometry results, and CT- and MRI-based volumetry were obtained before RFA and 6 months afterward. For the subjective parameters, the mean pre- and postoperative VAS scores for the 16 turbinates were 6.6 ± 1.6 and 2.8 ± 2.0 (p < 0.001), respectively, and the mean pre- and postoperative NOSE scores in the 9 patients were 15.3 ± 3.1 and 5.8 ± 5.4 (p = 0.003). For the objective parameters, the mean pre- and postoperative rhinomanometry values at 150 Pa were 241.0 ± 141.3 and 265.4 ± 157.3 ml/sec (p = 0.403), and the mean pre- and postoperative volumetry values were 5.3 ± 2.5 and 5.0 ± 2.1 cm(3) (p = 0.551). Note that only the differences in the subjective parameters reached statistical significance. RFA of the inferior turbinates as a treatment for nasal obstruction is safe and easy. However, our study found a discrepancy between the subjective and objective outcomes parameters, as the former showed highly significant improvement and the latter showed only a slight improvement that did not reach statistical significance.

  10. Developing a type-III wind turbine model for stability studies of the Hydro-Quebec network

    Energy Technology Data Exchange (ETDEWEB)

    Langlois, Charles-Eric; Lefebvre, Daniel [Hydro-Quebec TransEnergie, Montreal, QC (Canada); Dube, Laurent [DEI Technology, Montreal, QC (Canada); Gagnon, Richard [Hydro-Quebec IREQ, Varennes, QC (Canada)

    2009-07-01

    This paper presents a type-III (with DFIG) wind turbine model developed by Hydro-Quebec for stability studies. The model was built in EMTPWorks for use in PSS/E via an EMTP-PSS/E multi-model interface, also developed by Hydro-Quebec. The type-III model includes a physical representation of the asynchronous generator with rotor flux transients and two-mass shaft dynamics. The paper describes the turbine controls and discusses the design basis of the model. The model was validated with a full-transient detailed MATLAB/SimPowerSystems model developed by Hydro-Quebec. The latter was successfully compared with measurements from some disturbances on the Hydro-Quebec network. Test comparisons with a type-III generic model from the PSS/E library are presented. (orig.)

  11. Expert group study on recommended practices for wind turbine testing and evaluation. 10. Measurement of noise immission from wind turbines at noise receptor locations

    International Nuclear Information System (INIS)

    Ljunggren, S.

    1997-01-01

    The purpose of this guide is to provide a set of techniques and methods for the measurement and description of wind turbine noise immission, that is, wind turbine noise at receptor locations. These techniques and methods have been prepared so that they can be used by: manufacturers; developers; operators; planning authorities; research and development engineers, for the purpose of verification of compliance with noise immission limits and of noise propagation models. The measurement of noise immission from wind turbines is a complex acoustic task. This guideline cannot cover all possible problems that may be encountered on, for instance: determination of wind speed; measurements in cases of low signal-to-noise ratio; allowance for reflections from buildings. Thus, it is strongly recommended that the measurements described in this guide are always carried out by experienced acousticians. (au)

  12. Assessment of wind turbine seismic risk : existing literature and simple study of tower moment demand.

    Energy Technology Data Exchange (ETDEWEB)

    Prowell, Ian (University of California, San Diego, CA); Veers, Paul S.

    2009-03-01

    Various sources of risk exist for all civil structures, one of which is seismic risk. As structures change in scale, the magnitude of seismic risk changes relative to risk from other sources. This paper presents an introduction to seismic hazard as applied to wind turbine structures. The existing design methods and research regarding seismic risk for wind turbines is then summarized. Finally a preliminary assessment is made based on current guidelines to understand how tower moment demand scales as rated power increases. Potential areas of uncertainty in the application of the current guidelines are summarized.

  13. Wind turbine

    Science.gov (United States)

    Cheney, Jr., Marvin C.

    1982-01-01

    A wind turbine of the type having an airfoil blade (15) mounted on a flexible beam (20) and a pitch governor (55) which selectively, torsionally twists the flexible beam in response to wind turbine speed thereby setting blade pitch, is provided with a limiter (85) which restricts unwanted pitch change at operating speeds due to torsional creep of the flexible beam. The limiter allows twisting of the beam by the governor under excessive wind velocity conditions to orient the blades in stall pitch positions, thereby preventing overspeed operation of the turbine. In the preferred embodiment, the pitch governor comprises a pendulum (65,70) which responds to changing rotor speed by pivotal movement, the limiter comprising a resilient member (90) which engages an end of the pendulum to restrict further movement thereof, and in turn restrict beam creep and unwanted blade pitch misadjustment.

  14. State of the art of aerolastic codes for wind turbine calculations

    Energy Technology Data Exchange (ETDEWEB)

    Maribo Pedersen, B. [ed.

    1996-09-01

    The technological development of modern wind turbines has been dependent on the parallel development of the computational skills of the designers. The combination of the calculation of the flow field around the wind turbine rotor - both far field and near field - and the calculation of the response of the wind turbine structure to the resulting, non-stationary air loads, also known as aero-elastic calculations have now reached a reasonable degree of maturity. At this expert meeting two main points may be clarified. To what level of accuracy can we now determine the behaviour of the different elements of a wind turbine, i.e. how well are we able to compute deflections, fluctuating loads and power output. Which are the main outstanding areas upon which our next research efforts should be focused. (EG)

  15. Impacts of Providing Inertial Response on Dynamic Loads of Wind Turbine Drivetrains: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Girsang, I. P.; Dhupia, J.; Singh, M.; Gevorgian, V.; Muljadi, E.; Jonkman, J.

    2014-09-01

    There has been growing demand from the power industry for wind power plants to support power system operations. One such requirement is for wind turbines to provide ancillary services in the form of inertial response. When the grid frequency drops, it is essential for wind turbine generators (WTGs) to inject kinetic energy stored in their inertia into the grid to help arrest the frequency decline. However, the impacts of inertial response on the structural loads of the wind turbine have not been given much attention. To bridge this gap, this paper utilizes a holistic model for both fixed-speed and variable-speed WTGs by integrating the aeroelastic wind turbine model in FAST, developed by the National Renewable Energy Laboratory, with the electromechanical drivetrain model in SimDriveline and SimPowerSystems.

  16. Design, Optimization and Analysis of Hydraulic Soft Yaw System for 5 MW Wind Turbine

    DEFF Research Database (Denmark)

    Stubkier, Søren; Pedersen, Henrik C.

    2011-01-01

    As wind turbines increase in size and the demands for lifetime also increases, new methods of load reduction needs to be examined. One method is to make the yaw system of the turbine soft/flexible and hence dampen the loads to the system, which is the focus of the current paper. The paper first...... presents work previous done on this subject with focus on hydraulic yaw systems. By utilizing the HAWC2 aeroelastic code and an extended model of the NREL 5MW turbine combined with a simplified linear model of the turbine, the parameters of the soft yaw system are optimized. Results show that a significant...... reduction in fatigue and extreme loads to the yaw system and rotor shaft are possible, when utilizing the soft yaw drive concept compared to the original stiff yaw system. The physical demands of the hydraulic yaw system are furthermore examined for a life time of 20 years. The duty cycles, based...

  17. Comparative study on the performance of control systems for doubly fed induction generator (DFIG) wind turbines operating with power regulation

    International Nuclear Information System (INIS)

    Fernandez, L.M.; Garcia, C.A.; Jurado, F.

    2008-01-01

    As a result of the increasing wind power penetration on power systems, the wind farms are today required to participate actively in grid operation by an appropriate generation control. This paper presents a comparative study on the performance of three control strategies for DFIG wind turbines. The study focuses on the regulation of the active and reactive power to a set point ordered by the wind farm control system. Two of them (control systems 1 and 2) are based on existing strategies, whereas the third control system (control system 3) presents a novel control strategy, which is actually a variation of the control system 2. The control strategies are evaluated through simulations of DFIG wind turbines, under normal operating conditions, integrated in a wind farm with centralized control system controlling the wind farm generation at the connection point and computing the power reference for each wind turbine according to a proportional distribution of the available power. The three control systems present similar performance when they operate with power optimization and power limitation strategies. However, the control system 3 with down power regulation presents a better response with respect to the reactive power production, achieving a higher available reactive power as compared with the other two. This is a very important aspect to maintain an appropriate voltage control at the wind farm bus

  18. Before-after field study of effects of wind turbine noise on polysomnographic sleep parameters.

    Science.gov (United States)

    Jalali, Leila; Bigelow, Philip; Nezhad-Ahmadi, Mohammad-Reza; Gohari, Mahmood; Williams, Diane; McColl, Steve

    2016-01-01

    Wind is considered one of the most advantageous alternatives to fossil energy because of its low operating cost and extensive availability. However, alleged health-related effects of exposure to wind turbine (WT) noise have attracted much public attention and various symptoms, such as sleep disturbance, have been reported by residents living close to wind developments. Prospective cohort study with synchronous measurement of noise and sleep physiologic signals was conducted to explore the possibility of sleep disturbance in people hosting new industrial WTs in Ontario, Canada, using a pre and post-exposure design. Objective and subjective sleep data were collected through polysomnography (PSG), the gold standard diagnostic test, and sleep diary. Sixteen participants were studied before and after WT installation during two consecutive nights in their own bedrooms. Both audible and infrasound noises were also concurrently measured inside the bedroom of each participant. Different noise exposure parameters were calculated (LAeq, LZeq) and analyzed in relation to whole-night sleep parameters. Results obtained from PSG show that sleep parameters were not significantly changed after exposure. However, reported sleep qualities were significantly (P = 0.008) worsened after exposure. Average noise levels during the exposure period were low to moderate and the mean of inside noise levels did not significantly change after exposure. The result of this study based on advanced sleep recording methodology together with extensive noise measurements in an ecologically valid setting cautiously suggests that there are no major changes in the sleep of participants who host new industrial WTs in their community. Further studies with a larger sample size and including comprehensive single-event analyses are warranted.

  19. Before–After Field Study of Effects of Wind Turbine Noise on Polysomnographic Sleep Parameters

    Science.gov (United States)

    Jalali, Leila; Bigelow, Philip; Nezhad-Ahmadi, Mohammad-Reza; Gohari, Mahmood; Williams, Diane; McColl, Steve

    2016-01-01

    Wind is considered one of the most advantageous alternatives to fossil energy because of its low operating cost and extensive availability. However, alleged health-related effects of exposure to wind turbine (WT) noise have attracted much public attention and various symptoms, such as sleep disturbance, have been reported by residents living close to wind developments. Prospective cohort study with synchronous measurement of noise and sleep physiologic signals was conducted to explore the possibility of sleep disturbance in people hosting new industrial WTs in Ontario, Canada, using a pre and post-exposure design. Objective and subjective sleep data were collected through polysomnography (PSG), the gold standard diagnostic test, and sleep diary. Sixteen participants were studied before and after WT installation during two consecutive nights in their own bedrooms. Both audible and infrasound noises were also concurrently measured inside the bedroom of each participant. Different noise exposure parameters were calculated (LAeq, LZeq) and analyzed in relation to whole-night sleep parameters. Results obtained from PSG show that sleep parameters were not significantly changed after exposure. However, reported sleep qualities were significantly (P=0.008) worsened after exposure. Average noise levels during the exposure period were low to moderate and the mean of inside noise levels did not significantly change after exposure. The result of this study based on advanced sleep recording methodology together with extensive noise measurements in an ecologically valid setting cautiously suggests that there are no major changes in the sleep of participants who host new industrial WTs in their community. Further studies with a larger sample size and including comprehensive single-event analyses are warranted. PMID:27569407

  20. Design guidelines for passive instability suppression - Task-11 report[Wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, M.H.; Buhl, T.

    2006-12-15

    In these guidelines for passive instability suppression, eight relevant topics within aeroelastic stability of turbines are considered for the parameter variations: 1. Effect of airfoil aerodynamics: The airfoil aerodynamics given by the profile coefficients for aerodynamic lift, drag, and moment are shown to have a direct effect on aerodynamic damping of blade vibrations. A redesign of the airfoils can improve the power performance of the rotor without loss of aerodynamic damping. 2. Effect of flap/edgewise frequency coincidence: The natural frequencies of the first flapwise and first edgewise blade bending modes become closer as the blades become more slender. This 1-1 resonance may lead to a coupling flap- and edgewise blade vibrations which increases the edgewise blade mode damping. 3. Effect of flap/edgewise whirling coupling: The aerodynamic damping of blade vibrations close to the rotor plane are generally lower than the aerodynamic damping of vibrations out of the rotor plane. A structural coupling between the flapwise and edgewise whirling modes can increase the overall aerodynamic damping by adding more out of plane blade motion to the edgewise whirling modes. 4. Effect of torsional blade stiffness: A low torsional blade stiffness may lead to flutter where the first torsional blade mode couples to a flapwise bending mode in a flutter instability through the aerodynamic forces. 5. Can whirl flutter happen on a wind turbine? Whirl flutter is an aeroelastic instability similar to blade flutter. Whirl flutter can occur on turbines with very low natural frequencies of the tilt and yaw modes (about 5 % of their original values). 6. Edgewise/torsion coupling for large flapwise deflections: The large flapwise deflection of modern slender blades lead to a geometric coupling of edgewise bending and torsion. The aeroelastic damping of the blade modes are affected by a flapwise prebend of the blade. 7. Effect of yaw error on damping from wake: The wake behind the

  1. FINITE ELEMENT MODELLING OF A TURBINE BLADE TO STUDY THE EFFECT OF MULTIPLE CRACKS USING MODAL PARAMETERS

    Directory of Open Access Journals (Sweden)

    RAVI PRAKASH BABU KOCHARLA

    2016-12-01

    Full Text Available The presence of crack in a structure tends to modify its modal parameters (natural frequencies and mode shapes. The fact can be used inversely to predict the crack parameters (crack depth and its location from measurement of the changes in the modal parameters, once a functional relationship between them has been established. The machine components like turbine blade can be treated as a cantilever beam. Vibration analysis of cantilever beam can be extended successfully to develop online crack detection methodology in turbine blade. In the present work, finite element model of a cantilever beam for flexural vibrations has been considered by including two transverse open U-notches. The modal analysis has been carried out on cantilever beam with two U-notches and observed the influence of one U-notch on the other for natural frequencies and mode shapes. It is found that a certain frequency may correspond to different crack depths and locations. Later, by using a central difference approximation, curvature mode shapes were then calculated from the displacement mode shapes. The location and depth corresponding to any peak on this curve becomes a possible notch location and depth. The identification procedure presented in this study is a useful tool for detection of multiple cracks in a turbine blade.

  2. Parametric study on off-design aerodynamic performance of a horizontal axis wind turbine blade and proposed pitch control

    International Nuclear Information System (INIS)

    Najafian Ashrafi, Z.; Ghaderi, M.; Sedaghat, A.

    2015-01-01

    Highlights: • A pitch controlled 200 kW HAWT blade is designed with BEM for off-design conditions. • Parametric study conducted on power coefficient, axial and angular induction factors. • The optimal pitch angles were determined at off-design operating conditions. - Abstract: In this paper, a 200 kW horizontal axis wind turbine (HAWT) blade is designed using an efficient iterative algorithm based on the blade element momentum theory (BEM) on aerodynamic of wind turbines. The effects of off-design variations of wind speed are investigated on the blade performance parameters according to constant rotational speed of the rotor. The performance parameters considered are power coefficient, axial and angular induction factors, lift and drag coefficients on the blade, angle of attack and angle of relative wind. At higher or lower wind speeds than the designed rated speed, the power coefficient is reduced due to considerable changes in the angle of attacks. Therefore, proper pitch control angles were calculated to extract maximum possible power at various off-design speeds. The results showed a considerable improvement in power coefficient for the pitch controlled blade as compared with the baseline design in whole operating range. The present approach can be equally employed for determining pitch angles to design pitch control system of medium and large-scale wind turbines

  3. Study on the supercritical CO2 power cycles for landfill gas firing gas turbine bottoming cycle

    International Nuclear Information System (INIS)

    Kim, Min Seok; Ahn, Yoonhan; Kim, Beomjoo; Lee, Jeong Ik

    2016-01-01

    In this paper, a comparison of nine supercritical carbon dioxide (S-CO 2 ) bottoming power cycles in conjunction with a topping cycle of landfill gas (LFG) fired 5MWe gas turbine is presented. For the comparison purpose, a sensitivity study of the cycle design parameters for nine different cycles was conducted and each cycle thermodynamic performance is evaluated. In addition, the cycle performance evaluation dependency on the compressor inlet temperature variation is performed to investigate how S-CO 2 cycles sensitive to the heat sink temperature variation. Furthermore, the development of new S-CO 2 cycle layouts is reported and the suggested cycles' performances are compared to the existing cycle layouts. It was found that a recompression cycle is not suitable for the bottoming cycle application, but a partial heating cycle has relatively higher net produced work with a simple layout and small number of components. Although a dual heated and flow split cycle has the highest net produced work, it has disadvantages of having numerous components and complex process which requires more sophisticated operational strategies. This study identified that the recuperation process is much more important than the intercooling process to the S-CO 2 cycle design for increasing the thermal efficiency and the net produced work point of view. - Highlights: • Study of nine S-CO 2 power cycle layouts for a small scale landfill gas power generation application. • Development of new S-CO 2 cycle layouts. • Sensitivity analysis of S-CO 2 cycles to evaluate and compare nine cycles' performances.

  4. In-Flight Aeroelastic Stability of the Thermal Protection System on the NASA HIAD, Part I: Linear Theory

    Science.gov (United States)

    Goldman, Benjamin D.; Dowell, Earl H.; Scott, Robert C.

    2014-01-01

    Conical shell theory and piston theory aerodynamics are used to study the aeroelastic stability of the thermal protection system (TPS) on the NASA Hypersonic Inflatable Aerodynamic Decelerator (HIAD). Structural models of the TPS consist of single or multiple orthotropic conical shell systems resting on several circumferential linear elastic supports. The shells in each model may have pinned (simply-supported) or elastically-supported edges. The Lagrangian is formulated in terms of the generalized coordinates for all displacements and the Rayleigh-Ritz method is used to derive the equations of motion. The natural modes of vibration and aeroelastic stability boundaries are found by calculating the eigenvalues and eigenvectors of a large coefficient matrix. When the in-flight configuration of the TPS is approximated as a single shell without elastic supports, asymmetric flutter in many circumferential waves is observed. When the elastic supports are included, the shell flutters symmetrically in zero circumferential waves. Structural damping is found to be important in this case. Aeroelastic models that consider the individual TPS layers as separate shells tend to flutter asymmetrically at high dynamic pressures relative to the single shell models. Several parameter studies also examine the effects of tension, orthotropicity, and elastic support stiffness.

  5. An experimental study of the effect of mooring systems on the dynamics of a SPAR buoy-type floating offshore wind turbine

    Directory of Open Access Journals (Sweden)

    Sinpyo Hong

    2015-05-01

    Full Text Available An experimental study of the effect of mooring systems on the dynamics of a SPAR buoy-type floating offshore wind turbine is presented. The effects of the Center of Gravity (COG, mooring line spring constant, and fair-lead location on the turbine’s motion in response to regular waves are investigated. Experimental results show that for a typical mooring system of a SPAR buoy-type Floating Offshore Wind Turbine (FOWT, the effect of mooring systems on the dynamics of the turbine can be considered negligible. However, the pitch decreases notably as the COG increases. The COG and spring constant of the mooring line have a negligible effect on the fairlead displacement. Numerical simulation and sensitivity analysis show that the wind turbine motion and its sensitivity to changes in the mooring system and COG are very large near resonant frequencies. The test results can be used to validate numerical simulation tools for FOWTs.

  6. System design and optimization study of axial flow turbine applied in ...

    Indian Academy of Sciences (India)

    Margheritini et al (2009) proposed a wave energy converter of the overtopping type made up of a number of reservoirs and low head hydro-turbines. The pilot plant is an on-shore full-scale module in three levels with an expected power production of 320 MWh/y in the North. Sea. However, little research was investigated for ...

  7. Design study of a 10 MW MgB2 superconductor direct drive wind turbine generator

    NARCIS (Netherlands)

    Abrahamsen, A.B.; Magnusson, N.; Liu, D.; Stehouwer, E.; Hendriks, B.; Polinder, H.

    2014-01-01

    A superconducting direct drive generator based on field windings of MgB2 superconducting tape is proposed as a solution by mounting the generator in front of the blades using a king-pin nacelle design for offshore turbines with power ratings larger than 10 MW as investigated in the INNWIND.EU

  8. Design study of a 10 MW MgB2 superconductor direct drive wind turbine generator

    DEFF Research Database (Denmark)

    Abrahamsen, Asger Bech; Magnusson, Niklas; Liu, Dong

    2014-01-01

    A superconducting direct drive generator based on field windings of MgB2 superconducting tape is proposed as a solution by mounting the generator in front of the blades using a king-pin nacelle design for offshore turbines with power ratings larger than 10 MW as investigated in the INNWIND.EU pro...

  9. Design study of coated conductor direct drive wind turbine generator for small scale demonstration

    DEFF Research Database (Denmark)

    Abrahamsen, Asger Bech; Jensen, Bogi Bech

    2012-01-01

    We have investigated the properties of a superconducting direct drive generator suitable for demonstration in a small scale 11 kW wind turbine. The engineering current density of the superconducting field windings is based on properties of coated conductors wound into coils holding of the order 6...

  10. Experimental study of the efficiency of steam injection on wet-steam turbine stator blade cascade

    Science.gov (United States)

    Khomyakov, S. V.; Alexeev, R. A.; Gavrilov, I. Y.; Gribin, V. G.; Tishchenko, A. A.; Tishchenko, V. A.; Popov, V. V.

    2017-11-01

    Currently, in order to decrease the negative effects caused by the presence of a discrete phase in the flow path of steam turbines stages operating in wet-steam area, different technical solutions are apply. These methods reduce the number of coarse droplets and wetness of working medium. The implementation of erosion reduction methods requires modifying surfaces of flow path, which can significantly affect the efficiency of the steam turbine. For example application of intrachanel moisture removing and steam injection needs changes of the stator blades surfaces. This article is a part of researches cycle about the efficiency of steam injection on the stator blade surface as the main method of coarse liquid particles diameters reduction in the last stages of high-power steam turbines. The paper presents the results of the analysis and comparison of experimental research unmodified profile to the profile of the stator blade changed by injection slot. The comparison of the profile losses considered blades is present. The analysis of the experimental results showed the feasibility and efficiency of this method of coarse liquid particles diameters reduction in the last stages of high-power steam turbines.

  11. Study of DFIG Wind Turbine Fault Ride-Through According to The Danish Grid Code

    DEFF Research Database (Denmark)

    Abulanwar, Elsayed; Chen, Zhe; Bak-Jensen, Birgitte

    2013-01-01

    This paper presents a new decentralized control strategy to enable a Doubly-fed Induction generator wind turbine, DFIG WT, to fulfill the Danish grid code requirements during different perturbations. A nonlinear controller is adopted for the grid side converter, GSC, to ensure decoupled control...

  12. Numerical study of pyrolysis oil combustion in an industrial gas turbine

    NARCIS (Netherlands)

    Sallevelt, J.L.H.P.; Pozarlik, Artur Krzysztof; Brem, Gerrit

    2016-01-01

    The growing demand for the use of biofuels for decentralized power generation initiates new research in gas turbine technology. However, development of new combustors for low calorific fuels is costly in terms of time and money. To give momentum to biofuels application for power generation robust

  13. System design and optimization study of axial flow turbine applied in ...

    Indian Academy of Sciences (India)

    The axial flow turbine applied in an overtopping wave energy convertor can continuously provide power with ... Among various forms of ocean energy, the energy from ocean waves is the most abundantly available and applicable in offshore .... robustness and advanced modeling capabilities. ANSYS is renowned for CFD ...

  14. STUDI EKSPERIMEN PENGARUH SUDUT PITCH TERHADAP PERFORMA TURBIN ANGIN DARRIEUS-H SUMBU VERTIKAL NACA 0012

    Directory of Open Access Journals (Sweden)

    Nur Aklis

    2016-12-01

    Full Text Available Ketersediaan sumber daya energi fosil serta makin meningkatnya kesadaran akan usaha untuk melestarikan lingkungan  mendorong manusia untuk mengembangkan energy alternatif . Angin adalah salah satu sumber energi terbarukan yang ramah lingkungan. Energi angin dapat dimanfaatkan untuk menggerakkan turbin yang kemudian menggerakkan generator untuk menghasilkan listrik. Salah satu jenis turbin angin sumbu vertical yang banyak mendapat perhatian adalah Darrieus tipe-H. Penelitian ini bertujuan untuk mengetahui pengaruh sudut pitch terhadap performa turbin angin sumbu vertikal. Sudu didesain berdasar dengan aerofoil NACA 0012, dengan panjang chord 0,3 m. Dimater (D sudu  0,44 m dan tinggi (H 0,6 m. Variasi sudut pitch yang digunakan adalah (350, 400, 450, 500, 550, 600. Pengambilan data  ini dilakukan dengan menggunakan wind tunnel dengan kecepatan angin 4,8 m/s. Dari hasil pengujian diperoleh bahwa turbin angin dengan sudut pitch 550 lebih efektif dalam mengekstrak energi angin, dengan efesiensi masing-masing  4,62%,.

  15. Numerical Study of Active Flow Control for a Transitional Highly-Loaded Low-Pressure Turbine

    Science.gov (United States)

    2008-02-01

    Count Using Vortex Generator Jet Separation Control,” ASME Paper GT-2002-30602, Jun. 2002. [16] Eulitz, F. and Engel , K., “Numerical Investigation of...Around a Low Pressure Turbine Blade,” Direct and Large-Eddy Simulation IV, ERCOFTAC Series Vol. 8 , edited by B. J. Guerts, R. Friedrich , and O

  16. Flight Dynamic Simulation with Nonlinear Aeroelastic Interaction using the ROM-ROM Procedure, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — ZONA Technology, Inc. proposes to develop an integrated flight dynamics simulation capability with nonlinear aeroelastic interactions by combining a flight dynamics...

  17. Flight Dynamic Simulation with Nonlinear Aeroelastic Interaction using the ROM-ROM Procedure, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — ZONA Technology, Inc. (ZONA) proposes to develop an integrated flight dynamics simulation capability with nonlinear aeroelastic interactions by combining a flight...

  18. Effect of modified aerodynamic strip theories on rotor blade aeroelastic stability

    Science.gov (United States)

    Friedmann, P.; Yuan, C.

    1976-01-01

    Various existing unsteady aerodynamic strip theories which have been developed in the past for both fixed and rotary wing aeroelastic analyses are modified in the paper so as to make them applicable to the coupled flap-lag-torsional aeroelastic problem of a rotor blade in hover. These corrections are primarily due to constant angle of attack, constant inflow and variable free stream velocity due to lead-lag motion. Next, the modified strip theories are incorporated in a coupled flap-lag-torsional aeroelastic analysis of the rotor blade in hover and the sensitivity of the aeroelastic stability boundaries to the aerodynamic assumptions is examined.

  19. Wind Turbine Acoustics

    Science.gov (United States)

    Hubbard, Harvey H.; Shepherd, Kevin P.

    2009-01-01

    Wind turbine generators, ranging in size from a few kilowatts to several megawatts, are producing electricity both singly and in wind power stations that encompass hundreds of machines. Many installations are in uninhabited areas far from established residences, and therefore there are no apparent environmental impacts in terms of noise. There is, however, the potential for situations in which the radiated noise can be heard by residents of adjacent neighborhoods, particularly those neighborhoods with low ambient noise levels. A widely publicized incident of this nature occurred with the operation of the experimental Mod-1 2-MW wind turbine, which is described in detail elsewhere. Pioneering studies which were conducted at the Mod-1 site on the causes and remedies of noise from wind turbines form the foundation of much of the technology described in this chapter.

  20. A Numerical Model for a Floating TLP Wind Turbine

    DEFF Research Database (Denmark)

    Kumari Ramachandran, Gireesh Kumar Vasanta

    A numerical model is developed for a TLP configuration of a floating offshore wind turbine. The platform dynamics and hydrodynamic forces are derived and implemented in an advanced aero-elastic code, Flex5, to compute the hydro-aero-servo-elastic loads and responses on the floater and the wind...... turbine. This is achieved through three steps. In the first step, an independent 2D code with fourteen degrees of freedom (DOFs) is developed and the responses are verified for load cases concerning steady and spatially coherent turbulent wind with regular and irregular waves. In the second step, the 2D...... irregular waves. In addition, the effect of wind-wave misalignment is investigated. Further, in the third step, the 3D platform dynamics and wave loading are implemented into Flex5, resulting in a fully coupled hydro-aero-servo-elastic code. The implementation is tested to make the model reliable and robust...

  1. Wind tunnel tests of a free yawing downwind wind turbine

    DEFF Research Database (Denmark)

    Verelst, David Robert; Larsen, Torben J.; van Wingerden, J.W.

    2012-01-01

    During February and April 2012 a series of wind tunnel tests were performed at the TU Delft Open Jet Facility (OJF) with a three bladed downwind wind turbine and a rotor radius of 0.8 meters. The setup includes an off the shelf three bladed hub, nacelle and generator on which relatively flexible ...... in free yawing conditions. Further, the effect of the tower shadow passage on the blade flapwise strain measurement is evaluated. Finally, data from the experiment is compared with preliminary simulations using DTU Wind Energy's aeroelastic simulation program HAWC2.......During February and April 2012 a series of wind tunnel tests were performed at the TU Delft Open Jet Facility (OJF) with a three bladed downwind wind turbine and a rotor radius of 0.8 meters. The setup includes an off the shelf three bladed hub, nacelle and generator on which relatively flexible...

  2. Hydraulic Soft Yaw System for Multi MW Wind Turbines

    DEFF Research Database (Denmark)

    Stubkier, Søren

    by a systematic concept generation and analysis of different concepts, where a single concept is chosen for further analysis. A preliminary analysis, based on simulations of the NREL 5 MW turbine modified to include a soft yaw system, show that the soft yaw concept chosen leads to signicant load reductions...... in the wind turbine yaw system along with minor reductions in the blades and main shaft. Optimization of the damping and stiffness of the hydraulic soft yaw system have been conducted and an optimum found for load reduction. Linear control algorithms for control of damping pressure peaks have been developed...... and tested in simulations with success. To verify the results of the new hydraulic soft yaw concept a novel friction model for including coulomb in the yaw system is developed and implemented in the FAST aeroelastic code from NREL in order to include friction phenomena. A cosimulation interface between...

  3. Nasopharyngeal turbinates in brachycephalic dogs and cats.

    Science.gov (United States)

    Ginn, Jennifer A; Kumar, M S A; McKiernan, Brendan C; Powers, Barbara E

    2008-01-01

    This retrospective study reports the presence and incidence of nasal turbinates in the nasopharynx (nasopharyngeal turbinates) in a population of brachycephalic dogs and cats exhibiting signs of upper respiratory disease. Medical records were reviewed for 53 brachycephalic dogs and 10 brachycephalic cats undergoing upper airway endoscopy. Nasopharyngeal turbinates were identified in 21% of brachycephalic animals, including 21% of dogs and 20% of cats. Pugs accounted for 32% of all dogs in the study population and 82% of dogs with nasopharyngeal turbinates. The presence of nasopharyngeal turbinates may play a role in upper airway obstruction in the brachycephalic airway syndrome.

  4. Level-Set Topology Optimization with Aeroelastic Constraints

    Science.gov (United States)

    Dunning, Peter D.; Stanford, Bret K.; Kim, H. Alicia

    2015-01-01

    Level-set topology optimization is used to design a wing considering skin buckling under static aeroelastic trim loading, as well as dynamic aeroelastic stability (flutter). The level-set function is defined over the entire 3D volume of a transport aircraft wing box. Therefore, the approach is not limited by any predefined structure and can explore novel configurations. The Sequential Linear Programming (SLP) level-set method is used to solve the constrained optimization problems. The proposed method is demonstrated using three problems with mass, linear buckling and flutter objective and/or constraints. A constraint aggregation method is used to handle multiple buckling constraints in the wing skins. A continuous flutter constraint formulation is used to handle difficulties arising from discontinuities in the design space caused by a switching of the critical flutter mode.

  5. Aeroelastic tailoring via ribs orientation of NASA Common Research Model

    Science.gov (United States)

    Chan, Y. N.; Harmin, M. Y.; Rafie, A. S. M.

    2017-12-01

    A baseline model in reference to the NASA Common Research Model is selected to illustrate the concept of aeroelastic tailoring of wing ribs structure by varying the orientation of the ribs. This enables the torsional-bending modes characteristic to be altered, which results in a possibility of improvement in the aeroelastic performance without having to compromise its overall weight. Two strategies are implanted in this work: the first strategy considers the whole ribs to be oriented in parallel while the second one is by dividing the wing into six parts where the ribs are allowed to be oriented in parallel within their part only. In many cases, there are a significant improvement with up to 5.5% of flutter increment via orientating the ribs section, hence leading to a possibility in significant structural weight reduction.

  6. Constructal Theory and Aeroelastic Design of Flexible Flying Wing Aircraft

    Directory of Open Access Journals (Sweden)

    Pezhman Mardanpour

    2017-07-01

    Full Text Available The aeroelastic behavior of high-aspect-ratio very flexible flying wing is highly affected by the geometric nonlinearities of the aircraft structure. This paper reviews the findings on how these nonlinearities influence the structural and flight dynamics, and it shows that the aeroelastic flight envelope could significantly be extended with proper choices of design parameters such as engine placement. Moreover, in order to investigate the physics behind the effects of design parameters, constructal theory of design is reviewed. The constructal theory advances the philosophy of design as science, it states that the better structural design emerges when stress flow strangulation is avoided. Furthermore, it shows that airplanes, through their evolution, have obeyed theoretical allometric rules that unite their designs.

  7. A Teaching Experience: Aeroelasticity and the Finite Element Method

    Directory of Open Access Journals (Sweden)

    Mario Lázaro

    2015-07-01

    Full Text Available The aeroelastic modelling of aircraft structures is a fundamental area for the students of Aerospace Engineering Degree. This subject has a strongly multidisciplinary character and involves other several subjects like mechanics, vibrations, aerodynamics, structural analysis. Consequently, the students find stimulating the challenge of merging their knowledge at different areas. In this paper, a teaching experience on the solution of the aeroelastic problem of a 3D-wing through six different computer tasks is presented. The main objective is to attempt a relatively complex problem using a simple version of the Finite Element Method with only four degrees of freedom. The students begin creating the shape functions of the discrete model and finish solving the flutter instability problem.

  8. Aeroelastic Stability of a Four-Bladed Semi-Articulated Soft-Inplane Tiltrotor Model

    Science.gov (United States)

    Nixon, Mark W.; Langston, Chester W.; Singleton, Jeffrey D.; Piatak, David J.; Kvaternik, Raymond G.; Corso, Lawrence M.; Brown, Ross K.

    2003-01-01

    A new four-bladed, semi-articulated, soft-inplane rotor system, designed as a candidate for future heavy-lift rotorcraft, was tested at model scale on the Wing and Rotor Aeroelastic Testing System (WRATS), a 1/5-size aeroelastic wind-tunnel model based on the V-22. The experimental investigation included a hover test with the model in helicopter mode subject to ground resonance conditions, and a forward flight test with the model in airplane mode subject to whirl-flutter conditions. An active control system designed to augment system damping was also tested as part of this investigation. Results of this study indicate that the new four-bladed, soft-inplane rotor system in hover has adequate damping characteristics and is stable throughout its rotor-speed envelope. However, in airplane mode it produces very low damping in the key wing beam-bending mode, and has a low whirl-flutter stability boundary with respect to airspeed. The active control system was successful in augmenting the damping of the fundamental system modes, and was found to be robust with respect to changes in rotor speed and airspeed. Finally, conversion-mode dynamic loads were measured on the rotor and these were found to be signi.cantly lower for the new soft-inplane hub than for the previous baseline stiff - inplane hub.

  9. Using FUN3D for Aeroelastic, Sonic Boom, and AeroPropulsoServoElastic (APSE) Analyses of a Supersonic Configuration

    Science.gov (United States)

    Silva, Walter A.; Sanetrik, Mark D.; Chwalowski, Pawel; Connolly, Joseph; Kopasakis, George

    2016-01-01

    An overview of recent applications of the FUN3D CFD code to computational aeroelastic, sonic boom, and aeropropulsoservoelasticity (APSE) analyses of a low-boom supersonic configuration is presented. The overview includes details of the computational models developed including multiple unstructured CFD grids suitable for aeroelastic and sonic boom analyses. In addition, aeroelastic Reduced-Order Models (ROMs) are generated and used to rapidly compute the aeroelastic response and utter boundaries at multiple flight conditions.

  10. Aeroelastic Airworthiness Assesment of the Adaptive Compliant Trailing Edge Flaps

    Science.gov (United States)

    Herrera, Claudia Y.; Spivey, Natalie D.; Lung, Shun-fat; Ervin, Gregory; Flick, Peter

    2015-01-01

    The Adaptive Compliant Trailing Edge (ACTE) demonstrator is a joint task under the National Aeronautics and Space Administration Environmentally Responsible Aviation Project in partnership with the Air Force Research Laboratory and FlexSys, Inc. (Ann Arbor, Michigan). The project goal is to develop advanced technologies that enable environmentally friendly aircraft, such as adaptive compliant technologies. The ACTE demonstrator flight-test program encompassed replacing the Fowler flaps on the SubsoniC Aircraft Testbed, a modified Gulfstream III (Gulfstream Aerospace, Savannah, Georgia) aircraft, with control surfaces developed by FlexSys. The control surfaces developed by FlexSys are a pair of uniquely-designed unconventional flaps to be used as lifting surfaces during flight-testing to validate their structural effectiveness. The unconventional flaps required a multidisciplinary airworthiness assessment to prove they could withstand the prescribed flight envelope. Several challenges were posed due to the large deflections experienced by the structure, requiring non-linear analysis methods. The aeroelastic assessment necessitated both conventional and extensive testing and analysis methods. A series of ground vibration tests (GVTs) were conducted to provide modal characteristics to validate and update finite element models (FEMs) used for the flutter analyses for a subset of the various flight configurations. Numerous FEMs were developed using data from FlexSys and the ground tests. The flap FEMs were then attached to the aircraft model to generate a combined FEM that could be analyzed for aeroelastic instabilities. The aeroelastic analysis results showed the combined system of aircraft and flaps were predicted to have the required flutter margin to successfully demonstrate the adaptive compliant technology. This paper documents the details of the aeroelastic airworthiness assessment described, including the ground testing and analyses, and subsequent flight

  11. Unsteady airfoil flows with application to aeroelastic stability

    Energy Technology Data Exchange (ETDEWEB)

    Johansen, Jeppe

    1999-09-01

    The present report describes numerical investigation of two-dimensional unsteady airfoil flows with application to aeroelastic stability. The report is divided in two parts. Part A describes the purely aerodynamic part, while Part B includes the aeroelastic part. In Part A a transition prediction algorithm based on a simplified version of the e{sup n} method is proposed. Laminar Boundary Layer instability data are stored in a database from which stability characteristics can be extracted by interpolation. Input to the database are laminar integral boundary layer parameters. These are computed from an integral boundary layer formulation coupled to a Navier-Stokes flow solver. Five different airfoils are considered at fixed angle of attack, and the flow is computed assuming both fully turbulent and transitional flow and compared with experimental data. Results indicate that using a transition model the drag prediction is improved considerably. Also the lift is slightly improved. At high angles of attack transition will affect leading edge separation which again will affect the overall vortex shedding. If the transition point is not properly predicted this will affect the whole hysteresis curve. The transition model developed in the present work showed more stable predictions compared to the empirical transition model. In Part B a simple three degrees-of-freedom (DOF) structural dynamics model is developed and coupled to the aerodynamics models from Part A. A 2nd order accurate time integration scheme is used to solve the equations of motion. Two airfoils are investigated. The aeroelastic models predict stable conditions well at low angle of attack. But at high angles of attack, and where unstable behaviour is expected, only the Navier-Stokes solver predict correct aeroelastic response. The semi-empirical dynamic stall model does not predict vortex shedding and moment correctly leading to an erroneous aerodynamic damping. (au) 5 tabs.; 55 ills., 52 refs.

  12. Static Aeroelastic Analysis with an Inviscid Cartesian Method

    Science.gov (United States)

    Rodriguez, David L.; Aftosmis, Michael J.; Nemec, Marian; Smith, Stephen C.

    2014-01-01

    An embedded-boundary, Cartesian-mesh flow solver is coupled with a three degree-of-freedom structural model to perform static, aeroelastic analysis of complex aircraft geometries. The approach solves a nonlinear, aerostructural system of equations using a loosely-coupled strategy. An open-source, 3-D discrete-geometry engine is utilized to deform a triangulated surface geometry according to the shape predicted by the structural model under the computed aerodynamic loads. The deformation scheme is capable of modeling large deflections and is applicable to the design of modern, very-flexible transport wings. The coupling interface is modular so that aerodynamic or structural analysis methods can be easily swapped or enhanced. After verifying the structural model with comparisons to Euler beam theory, two applications of the analysis method are presented as validation. The first is a relatively stiff, transport wing model which was a subject of a recent workshop on aeroelasticity. The second is a very flexible model recently tested in a low speed wind tunnel. Both cases show that the aeroelastic analysis method produces results in excellent agreement with experimental data.

  13. Non-linear aeroelastic prediction for aircraft applications

    Science.gov (United States)

    de C. Henshaw, M. J.; Badcock, K. J.; Vio, G. A.; Allen, C. B.; Chamberlain, J.; Kaynes, I.; Dimitriadis, G.; Cooper, J. E.; Woodgate, M. A.; Rampurawala, A. M.; Jones, D.; Fenwick, C.; Gaitonde, A. L.; Taylor, N. V.; Amor, D. S.; Eccles, T. A.; Denley, C. J.

    2007-05-01

    Current industrial practice for the prediction and analysis of flutter relies heavily on linear methods and this has led to overly conservative design and envelope restrictions for aircraft. Although the methods have served the industry well, it is clear that for a number of reasons the inclusion of non-linearity in the mathematical and computational aeroelastic prediction tools is highly desirable. The increase in available and affordable computational resources, together with major advances in algorithms, mean that non-linear aeroelastic tools are now viable within the aircraft design and qualification environment. The Partnership for Unsteady Methods in Aerodynamics (PUMA) Defence and Aerospace Research Partnership (DARP) was sponsored in 2002 to conduct research into non-linear aeroelastic prediction methods and an academic, industry, and government consortium collaborated to address the following objectives: To develop useable methodologies to model and predict non-linear aeroelastic behaviour of complete aircraft. To evaluate the methodologies on real aircraft problems. To investigate the effect of non-linearities on aeroelastic behaviour and to determine which have the greatest effect on the flutter qualification process. These aims have been very effectively met during the course of the programme and the research outputs include: New methods available to industry for use in the flutter prediction process, together with the appropriate coaching of industry engineers. Interesting results in both linear and non-linear aeroelastics, with comprehensive comparison of methods and approaches for challenging problems. Additional embryonic techniques that, with further research, will further improve aeroelastics capability. This paper describes the methods that have been developed and how they are deployable within the industrial environment. We present a thorough review of the PUMA aeroelastics programme together with a comprehensive review of the relevant research

  14. Offshore and onshore wind turbine wake meandering studied in an ABL wind tunnel

    DEFF Research Database (Denmark)

    Barlas, Emre; Buckingham, Sophia; Glabeke, Gertjan

    2015-01-01

    Scaled wind turbine models have been installed in the VKI L1-B atmospheric boundary layer wind tunnel at offshore and onshore conditions. Time-resolved measurements were carried out with three component hot wire anemometry and stereo-PIV in the middle vertical plane of the wake up to eleven turbine...... spectrum, present in the entire wake mainly for offshore inflow condition. It was found that the Strouhal number, based on the rotor diameter and the wind velocity at hub height, was in the order of 0.25. Below the meandering frequency, turbulence power spectrum decreased, whereas above it increased. Wake...... diameter downstream. The results show an earlier wake recovery for the onshore case. The effect of inflow conditions and the wind turbine’s working conditions on wake meandering was investigated. Wake meandering was detected by hot wire anemometry through a low frequency peak in the turbulent power...

  15. Wind tunnel study of helical and straight-bladed vertical-axis wind turbine wakes

    Science.gov (United States)

    Bagheri, Maryam; Araya, Daniel

    2017-11-01

    It is hypothesized that blade curvature can serve as a passive means to control fluid entrainment and wake recovery in vertical-axis wind turbine (VAWT) arrays. We test this experimentally in a wind tunnel using two different VAWT configurations, one with straight blades and another with helical blades, keeping all other experimental parameters fixed. A small-scale, commercially available VAWT (15W max power) is used as the baseline wind tunnel model in each case. The commercial VAWT blades are replaced with either straight or helical blades that are 3D-printed extrusions of the same airfoil cross-section. Results from smoke flow visualization, three-component wake velocity measurements, and turbine power data are presented. These results give insight into the potential use of VAWTs with curved blades in utility-scale wind farms.

  16. Converter controls and flicker study of PMSG-based grid connected wind turbines

    Directory of Open Access Journals (Sweden)

    Ali H. Kasem Alaboudy

    2013-03-01

    Full Text Available With the increased penetration of wind power, the influence of wind turbine generators on the grid power quality stipulates careful investigation and analysis. Direct driven permanent magnet synchronous generator (PMSG with a back-to-back converter set is one of the promising technologies in wind power generation schemes. In this paper, comprehensive models of wind turbine are used to analyze power and voltage fluctuations. The short time flicker index is used to assess the voltage fluctuation emitted. The control scheme of the grid-side converter is supported with a voltage regulation loop to reduce flicker emission. The effects of grid and site parameters on voltage fluctuation are investigated. Simulation results show that reduced flicker emissions are given when the developed voltage regulation loop is activated. Reasonable values of grid and site parameters contribute in the minimization of voltage fluctuation and flicker emission levels.

  17. A Study of Wind Turbine Comprehensive Operational Assessment Model Based on EM-PCA Algorithm

    Science.gov (United States)

    Zhou, Minqiang; Xu, Bin; Zhan, Yangyan; Ren, Danyuan; Liu, Dexing

    2018-01-01

    To assess wind turbine performance accurately and provide theoretical basis for wind farm management, a hybrid assessment model based on Entropy Method and Principle Component Analysis (EM-PCA) was established, which took most factors of operational performance into consideration and reach to a comprehensive result. To verify the model, six wind turbines were chosen as the research objects, the ranking obtained by the method proposed in the paper were 4#>6#>1#>5#>2#>3#, which are completely in conformity with the theoretical ranking, which indicates that the reliability and effectiveness of the EM-PCA method are high. The method could give guidance for processing unit state comparison among different units and launching wind farm operational assessment.

  18. Hydraulic turbines and auxiliary equipment

    Energy Technology Data Exchange (ETDEWEB)

    Luo Gaorong [Organization of the United Nations, Beijing (China). International Centre of Small Hydroelectric Power Plants

    1995-07-01

    This document presents a general overview on hydraulic turbines and auxiliary equipment, emphasizing the turbine classification, in accordance with the different types of turbines, standard turbine series in China, turbine selection based on the basic data required for the preliminary design, general hill model curves, chart of turbine series and the arrangement of application for hydraulic turbines, hydraulic turbine testing, and speed regulating device.

  19. Analytical Study of Losses at Off-design Conditions for a Fixed Geometry Turbine

    Science.gov (United States)

    Stewart, Warner L; Evans, David G

    1954-01-01

    An analytical investigation was made to determine the off-design loss characteristics of a fixed-geometry turbine of which the experimental performance was known. The method of analysis utilized an effective loss parameter and assumed that the velocity normal to the blade entrance angle was lost as a total-pressure loss. The method also assumed constant tangential component of velocity between the station just upstream and just downstream of the stator and rotor trailing edge. Good correlation between the analytically and experimentally obtained performance was found over the entire map until limiting loading was approached. The large decrease in efficiency at low-speed high pressure ratios and at high-speed low pressure ratios was found in the analysis to be almost entirely due to the rotor incidence and turbine exit whirl losses. From the results of the investigation it was concluded that for turbines designed to operate efficiently at more than one point, the design must compromise rotor incidence angle and exit whirl losses.

  20. Comparative study of the behavior of wind-turbines in a wind farm

    Energy Technology Data Exchange (ETDEWEB)

    Migoya, Emilio; Crespo, Antonio; Garcia, Javier; Manuel, Fernando; Jimenez, Angel [Universidad Politecnica de Madrid (UPM), Madrid (Spain). Departamento de Ingenieria Energetica y Fluidomecanica, Laboratorio de Mecanica de Fluidos; Moreno, Fermin [Comision Nacional de la Energia, Madrid (Spain); Costa, Alexandre [Energia Eolica, Division de Energias Renovables, CIEMAT, Madrid (Spain)

    2007-10-15

    The Sotavento wind farm is an experimental wind farm which has different types of wind turbines. It is located in an area whose topography is moderately complex, and where wake effects can be significant. One of the objectives of Sotavento wind farm is to compare the performances of the different machines; particularly regarding power production, maintenance and failures. However, because of wakes and topography, the different machines are not working under identical conditions. Two linearized codes have been used to estimate topography effects: UPMORO and WAsP. For wind directions in which topography is abrupt, the non-linear flow equations have been solved with the commercial code FLUENT, although the results are only qualitatively used. For wake effects, the UPMPARK code has been applied. As a result, the incident velocity over each wind turbine is obtained, and the power production is estimated by means of the power curve of each machine. Experimental measurements give simultaneously the wind characteristics at the measuring stations, the wind velocity, at the nacelle anemometer, and the power production of each wind turbine. These experimental results are employed to validate the numerical predictions. The main objective of this work is to deduce and validate a relationship between the wind characteristics measured in the anemometers and the wind velocity and the power output in each machine. (author)

  1. Turbine imaging technology assessment

    Energy Technology Data Exchange (ETDEWEB)

    Moursund, R. A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Carlson, T. J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2004-12-01

    The goal of this project was to identify and evaluate imaging technologies for observing juvenile fish within a Kaplan turbine, and specifically that would enable scientists to determine mechanisms of fish injury within an operating turbine unit. This report documents the opportunities and constraints for observing juvenile fish at specific locations during turbine passage. These observations were used to make modifications to dam structures and operations to improve conditions for fish passage while maintaining or improving hydropower production. The physical and hydraulic environment that fish experience as they pass through the hydroelectric plants were studied and the regions with the greatest potential for injury were defined. Biological response data were also studied to determine the probable types of injuries sustained in the turbine intake and what types of injuries are detectable with imaging technologies. The study grouped injury-causing mechanisms into two categories: fluid (pressure/cavitation, shear, turbulence) and mechanical (strike/collision, grinding/pinching, scraping). The physical constraints of the environment, together with the likely types of injuries to fish, provided the parameters needed for a rigorous imaging technology evaluation. Types of technology evaluated included both tracking and imaging systems using acoustic technologies (such as sonar and acoustic tags) and optic technologies (such as pulsed-laser videography, which is high-speed videography using a laser as the flash). Criteria for determining image data quality such as frame rate, target detectability, and resolution were used to quantify the minimum requirements of an imaging sensor.

  2. PI controller design of a wind turbine: evaluation of the pole-placement method and tuning using constrained optimization

    DEFF Research Database (Denmark)

    Mirzaei, Mahmood; Tibaldi, Carlo; Hansen, Morten Hartvig

    2016-01-01

    PI/PID controllers are the most common wind turbine controllers. Normally a first tuning is obtained using methods such as pole-placement or Ziegler-Nichols and then extensive aeroelastic simulations are used to obtain the best tuning in terms of regulation of the outputs and reduction of the loads...... to automatically tune the wind turbine controller subject to robustness constraints. The properties of the system such as the maximum sensitivity and complementary sensitivity functions (Ms and Mt), along with some of the responses of the system, are used to investigate the controller performance and formulate...

  3. Design and testing of an aeroelastically tailored wing under manoeuvre loading

    NARCIS (Netherlands)

    Werter, N.P.M.; Sodja, J.; De Breuker, R.

    2015-01-01

    The design methodology and testing of an aeroelastically tailored wing subjected to manoeuvre loads is presented in this paper. The wing is designed using an aeroelastic analysis tool that is composed of a closely coupled nonlinear beam model and a vortex lattice aerodynamic model. The globally

  4. Preliminary study of Friction disk type turbine for S-CO{sub 2} cycle application (2016 Autumn Meeting of the KNS)

    Energy Technology Data Exchange (ETDEWEB)

    Baik, Seungjoon; Heo, Jin Young; Kwon, Jinsu; Lee, Jeong Ik [KAIST, Daejeon (Korea, Republic of)

    2016-10-15

    Among the next generation reactors, a sodium-cooled fast reactor (SFR) with the supercritical carbon dioxide (S-CO{sub 2}) Brayton cycle has been suggested as the advanced energy solution. The S-CO{sub 2} power conversion system can achieve high efficiency with the SFR core thermal condition (450-550℃) and also can reduce the total cycle footprint due to high density of the working fluid. Moreover, the S-CO{sub 2} power cycle can reduce the accident consequence compared to the steam Rankine cycle due to the mild sodium-CO{sub 2} interaction. The S-CO{sub 2} power cycle has different characteristic compare to the conventional steam Rankine cycle or gas Brayton cycle. For the turbine section, the expansion ratio is much smaller than the other cycles. Thus, different type of turbine should be evaluated for the advanced S-CO{sub 2} technology and the KAIST research team considered a friction disk type turbine (Tesla turbine) concept for the S-CO{sub 2} cycle applications. In this paper, the test result and analysis of a lab-scale Tesla turbine in the KAIST S-CO{sub 2} experimental facility (S-CO{sub 2}PE) are briefly discussed. The KAIST research team investigated a friction disk type turbine, named as Tesla turbine, for the S-CO{sub 2} power cycle applications. The preliminary test of a lab-scale Tesla turbine was conducted with compressed air. The generator, nozzle angle and bearing performances are tested. With the best performing nozzle angle and bearing, the Tesla turbine was tested under various S-CO{sub 2} conditions. As a result, the S-CO{sub 2}PE facility generated electricity (0.5-5W). The isentropic efficiency was relatively low (0.8-1.3%). It seemed that, the authors need further study to understand the main mechanism and maximize the efficiency. After developing the design methodology, the design optimization will be conducted to show the applicability of the friction disk type turbine for the S-CO{sub 2} power cycle.

  5. A study of a high temperature nuclear power plant incorporating a non-integrated indirect cycle gas turbine

    International Nuclear Information System (INIS)

    Sarlos, G.; Helbling, W.; Zollinger, E.; Gregory, N.; Luchsinger, H.

    1982-04-01

    In connection with the HHT-project, the Swiss Federal Institute for Reactor Research has performed a study of a 1640-MWth HTR-plant incorporating a non-integrated indirect cycle gas turbine with two-stage intercooling, as a possibility of simplifying and reducing the cost of the HHT-demonstration plant. In this paper, the plant design is described and compared with the HHT-demonstration plant (a CCGT integrated plant with single stage intercooling). Also included is an evaluation of the various advantages and disadvantages of this design together with the presentation of some of the sensitivity results. (Auth.)

  6. Feasibility Study of Economics and Performance of Wind Turbine Generators at the Newport Indiana Chemical Depot Site

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, Joseph Owen [National Renewable Energy Lab. (NREL), Golden, CO (United States); Mosey, Gail [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2013-11-01

    The U.S. Environmental Protection Agency (EPA), in accordance with the RE-Powering America's Land initiative, selected the Newport Indiana Chemical Depot site in Newport, Indiana, for a feasibility study of renewable energy production. The National Renewable Energy Laboratory (NREL) was contacted to provide technical assistance for this project. The purpose of this report is to assess the sitefor possible wind turbine electrical generator installation and estimate the cost, performance, and site impacts of different wind energy options. In addition, the report recommends financing options that could assist in the implementation of a wind system at the site.

  7. Dynamic behaviour studies of a vertical axis wind turbine blade using Operational Modal Analysis (OMA) and Experimental Modal Analysis (EMA)

    DEFF Research Database (Denmark)

    Najafi, Nadia; Schmidt Paulsen, Uwe; Belloni, F.

    Dynamic behavior of a modified blade fitted onto a small 1 kW vertical-axis wind turbine is studied by two different approaches: Classical modal analysis (EMA) is carried out to validate the results of Operational Modal Analysis (OMA). In traditional modal analysis (EMA) one axis accelerometers...... different points. This process continues until the data set contains all the points with their degrees of freedom. Finally the frequency response function (FRF) is obtained for all points, and the natural frequencies and the mode shapes are estimated by peak picking method. Operational Modal Analysis (OMA...

  8. Experimental wind tunnel study of a smart sensing skin for condition evaluation of a wind turbine blade

    Science.gov (United States)

    Downey, Austin; Laflamme, Simon; Ubertini, Filippo

    2017-12-01

    Condition evaluation of wind turbine blades is difficult due to their large size, complex geometry and lack of economic and scalable sensing technologies capable of detecting, localizing, and quantifying faults over a blade’s global area. A solution is to deploy inexpensive large area electronics over strategic areas of the monitored component, analogous to sensing skin. The authors have previously proposed a large area electronic consisting of a soft elastomeric capacitor (SEC). The SEC is highly scalable due to its low cost and ease of fabrication, and can, therefore, be used for monitoring large-scale components. A single SEC is a strain sensor that measures the additive strain over a surface. Recently, its application in a hybrid dense sensor network (HDSN) configuration has been studied, where a network of SECs is augmented with a few off-the-shelf strain gauges to measure boundary conditions and decompose the additive strain to obtain unidirectional surface strain maps. These maps can be analyzed to detect, localize, and quantify faults. In this work, we study the performance of the proposed sensing skin at conducting condition evaluation of a wind turbine blade model in an operational environment. Damage in the form of changing boundary conditions and cuts in the monitored substrate are induced into the blade. An HDSN is deployed onto the interior surface of the substrate, and the blade excited in a wind tunnel. Results demonstrate the capability of the HDSN and associated algorithms to detect, localize, and quantify damage. These results show promise for the future deployment of fully integrated sensing skins deployed inside wind turbine blades for condition evaluation.

  9. Turbine stage model

    International Nuclear Information System (INIS)

    Kazantsev, A.A.

    2009-01-01

    A model of turbine stage for calculations of NPP turbine department dynamics in real time was developed. The simulation results were compared with manufacturer calculations for NPP low-speed and fast turbines. The comparison results have shown that the model is valid for real time simulation of all modes of turbines operation. The model allows calculating turbine stage parameters with 1% accuracy. It was shown that the developed turbine stage model meets the accuracy requirements if the data of turbine blades setting angles for all turbine stages are available [ru

  10. Analysis and modeling of unsteady aerodynamics with application to wind turbine blade vibration at standstill conditions

    DEFF Research Database (Denmark)

    Skrzypinski, Witold Robert

    Wind turbine blade vibrations at standstill conditions were investigated in the present work. These included vortex-induced and stall-induced vibrations. Thus, it was investigated whether the stand still vibrations are vortex-induced, stall-induced or a combination of both types. The work comprised...... limits. The motivation for it was that the standard aerodynamics existing in state-of-the-art aeroelastic codes is effectively quasi-steady in deep stall. If such an assumption was incorrect, these codes could predict stall-induced vibrations inaccurately. The main conclusion drawn from these analyzes...... was that even a relatively low amount of temporal lag in the aerodynamic response may significantly increase the aerodynamic damping and therefore influence the aeroelastic stability limits, relative to quasisteady aerodynamic response. Two- and three-dimensional CFD computations included non-moving, prescribed...

  11. Predicting the aeroelastic behavior of a wind-tunnel model using transonic small disturbance theory

    Science.gov (United States)

    Silva, Walter A.; Bennett, Robert M.

    1990-01-01

    The CAP-TSD (Computational Aeroelasticity Program - Transonic Small Disturbance) code, developed at the NASA-Langley Research Center, is applied to the Active Flexible Wing (AFW) wind-tunnel model for prediction of the model's transonic aeroelastic behavior. Static aeroelastic solutions using CAP-TSD are computed. Dynamic (flutter) analyses are then performed as perturbations about the static aeroelastic deformations of the AFW. The accuracy of the static aeroelastic procedure is investigated by comparing analytical results to those from AFW wind-tunnel experiments. Dynamic results are presented in the form of root loci at different Mach numbers for a heavy gas and for air test mediums. The resultant flutter boundaries for both gases, and the effects of viscous damping and angle of attack on the flutter boundary in air, are also presented.

  12. Impact of the Diurnal Cycle of the Atmospheric Boundary Layer on Wind-Turbine Wakes: A Numerical Modelling Study

    Science.gov (United States)

    Englberger, Antonia; Dörnbrack, Andreas

    2018-03-01

    The wake characteristics of a wind turbine for different regimes occurring throughout the diurnal cycle are investigated systematically by means of large-eddy simulation. Idealized diurnal cycle simulations of the atmospheric boundary layer are performed with the geophysical flow solver EULAG over both homogeneous and heterogeneous terrain. Under homogeneous conditions, the diurnal cycle significantly affects the low-level wind shear and atmospheric turbulence. A strong vertical wind shear and veering with height occur in the nocturnal stable boundary layer and in the morning boundary layer, whereas atmospheric turbulence is much larger in the convective boundary layer and in the evening boundary layer. The increased shear under heterogeneous conditions changes these wind characteristics, counteracting the formation of the night-time Ekman spiral. The convective, stable, evening, and morning regimes of the atmospheric boundary layer over a homogeneous surface as well as the convective and stable regimes over a heterogeneous surface are used to study the flow in a wind-turbine wake. Synchronized turbulent inflow data from the idealized atmospheric boundary-layer simulations with periodic horizontal boundary conditions are applied to the wind-turbine simulations with open streamwise boundary conditions. The resulting wake is strongly influenced by the stability of the atmosphere. In both cases, the flow in the wake recovers more rapidly under convective conditions during the day than under stable conditions at night. The simulated wakes produced for the night-time situation completely differ between heterogeneous and homogeneous surface conditions. The wake characteristics of the transitional periods are influenced by the flow regime prior to the transition. Furthermore, there are different wake deflections over the height of the rotor, which reflect the incoming wind direction.

  13. Development of an Offshore Direct-Drive Wind Turbine Model by Using a Flexible Multibody Simulation (Poster)

    Energy Technology Data Exchange (ETDEWEB)

    Bergua, R.; Jove, J.; Campbell, J.; Guo, Y.; Van Dam, J.

    2014-05-01

    Modern wind turbines are complex, highly-coupled systems. The dynamic interaction between various components is especially pronounced for multi-megawatt wind turbines. As a result, design process is generally split in several phases. First step consists of creating a global aero-elastic model that includes essential dynamics of structural components using the minimum-possible number of degrees of freedom (d.o.f.). The most important simplifications concern drivetrain and rotor-nacelle assembly (RNA). This approach has been shown valid for several wind turbine configurations. Nevertheless, with increasing size of wind turbines, any simplified design approach must be validated. The present work deals with the comparison and validation of the two modeling approaches for directdrive offshore wind turbines. ARNA/drivetrain model idealized as collection of lumped masses and springs is compared to a detailed Finite Element Method (FEM) based model. The comparison between models focuses on dynamic loads concerning drivetrain system. The comparison is performed in several operational conditions in order to explore the range of validity of the simplified model. Finally, the paper proposes a numerical-based workflow to assess the validity of simplified models of RNA/drivetrain in an aero-elastic global WT model.

  14. Experimental Study of a Reference Model Vertical-Axis Cross-Flow Turbine

    OpenAIRE

    Bachant, Peter; Wosnik, Martin; Gunawan, Budi; Neary, Vincent S.

    2016-01-01

    The mechanical power, total rotor drag, and near-wake velocity of a 1:6 scale model (1.075 m diameter) of the US Department of Energy?s Reference Model vertical-axis cross-flow turbine were measured experimentally in a towing tank, to provide a comprehensive open dataset for validating numerical models. Performance was measured for a range of tip speed ratios and at multiple Reynolds numbers by varying the rotor?s angular velocity and tow carriage speed, respectively. A peak power coefficient...

  15. STUDY THE EFFECT OF ERROSION ON THE BREAKAGE OF STEAM TURBINE BLADE AT BAIJI POWER STATION

    Directory of Open Access Journals (Sweden)

    Mohaned A. Daher

    2013-05-01

    Full Text Available The last stage endured on obvious erosion especially the front and the end of the blade. The erosion caused the appearance some cracks in this place. These remarks coincided with the theoretic   al results, which were acquired according to the condition of the turbine of station which showed that the droplet, which collided with the blade ends, caused high pressure on the surface of the blade and caused the occurrence of the corrosion. The danger of the erosion unavoidable due to its relationship with tae station efficiency and the only to avoid that is the use of the blade made of erosion resistance ingots.

  16. Design study on evaluation for power conversion system concepts in high temperature gas cooled reactor with gas turbine

    International Nuclear Information System (INIS)

    Minatsuki, Isao; Mizokami, Yorikata

    2007-01-01

    The design studies on High Temperature Gas Cooled Reactor with Gas Turbine (HTGR-GT) have been performed, which were mainly promoted by Japan Atomic Energy Agency (JAEA) and supported by fabricators in Japan. HTGR-GT plant feature is almost determined by selection of power conversion system concepts. Therefore, plant design philosophy is observed characteristically in selection of them. This paper describes the evaluation and analysis of the essential concepts of the HTGR-GT power conversion system through the investigations based on our experiences and engineering knowledge as a fabricator. As a result, the following concepts were evaluated that have advantages against other competitive one, such as the horizontal turbo machine rotor, the turbo machine in an individual vessel, the turbo machine with single shaft, the generator inside the power conversion vessel, and the power conversion system cycle with an intercooler. The results of the study can contribute as reference data when the concepts will be selected. Furthermore, we addressed reasonableness about the concept selection of the Gas Turbine High Temperature Reactor GTHTR300 power conversion system, which has been promoted by JAEA. As a conclusion, we recognized the GTHTR300 would be one of the most promising concepts for commercialization in near future. (author)

  17. Design, Optimization and Analysis of Hydraulic Soft Yaw System for 5 MW Wind Turbine

    DEFF Research Database (Denmark)

    Stubkier, Søren; Pedersen, Henrik C.

    2011-01-01

    presents work previous done on this subject with focus on hydraulic yaw systems. By utilizing the HAWC2 aeroelastic code and an extended model of the NREL 5MW turbine combined with a simplified linear model of the turbine, the parameters of the soft yaw system are optimized. Results show that a significant...... reduction in fatigue and extreme loads to the yaw system and rotor shaft are possible, when utilizing the soft yaw drive concept compared to the original stiff yaw system. The physical demands of the hydraulic yaw system are furthermore examined for a life time of 20 years. The duty cycles, based...... on the extrapolated loads, show that it is possible to construct a hydraulic soft yaw system, which is able to reduce the loads on the wind turbine significantly....

  18. The results of pre-design studies on the development of a new design of gas turbine compressor package of GPA-C-16 type

    Science.gov (United States)

    Smirnov, A. V.; Chobenko, V. M.; Shcherbakov, O. M.; Ushakov, S. M.; Parafiynyk, V. P.; Sereda, R. M.

    2017-08-01

    The article summarizes the results of analysis of data concerning the operation of turbocompressor packages at compressor stations for the natural gas transmission system of Ukraine. The basic requirements for gas turbine compressor packages used for modernization and reconstruction of compressor stations are considered. Using a 16 MW gas turbine package GPA-C-16S/76-1,44M1 as an example, the results of pre-design studies and some technical solutions that improve the energy efficiency of gas turbine compressor packages and their reliability, as well as its environmental performance are given. In particular, the article deals with the matching of performance characteristics of a centrifugal compressor (hereinafter compressor) and gas turbine drive to reduce fuel gas consumption; as well as application of energy efficient technologies, in particular, exhaust gas heat recovery units and gas-oil heat exchangers in turbocompressor packages oil system; as well as reducing emissions of carbon monoxide into the atmosphere using a catalytic exhaust system. Described technical solutions can be used for development of other types of gas turbine compressor packages.

  19. Energy Conversion Alternatives Study (ECAS), Westinghouse phase 1. Volume 5: Combined gas-steam turbine cycles. [energy conversion efficiency in electric power plants

    Science.gov (United States)

    Amos, D. J.; Foster-Pegg, R. W.; Lee, R. M.

    1976-01-01

    The energy conversion efficiency of gas-steam turbine cycles was investigated for selected combined cycle power plants. Results indicate that it is possible for combined cycle gas-steam turbine power plants to have efficiencies several point higher than conventional steam plants. Induction of low pressure steam into the steam turbine is shown to improve the plant efficiency. Post firing of the boiler of a high temperature combined cycle plant is found to increase net power but to worsen efficiency. A gas turbine pressure ratio of 12 to 1 was found to be close to optimum at all gas turbine inlet temperatures that were studied. The coal using combined cycle plant with an integrated low-Btu gasifier was calculated to have a plant efficiency of 43.6%, a capitalization of $497/kW, and a cost of electricity of 6.75 mills/MJ (24.3 mills/kwh). This combined cycle plant should be considered for base load power generation.

  20. Parametric studies on different gas turbine cycles for a high temperature gas-cooled reactor

    International Nuclear Information System (INIS)

    Wang Jie; Gu Yihua

    2005-01-01

    The high temperature gas-cooled reactor (HTGR) coupled with turbine cycle is considered as one of the leading candidates for future nuclear power plants. In this paper, the various types of HTGR gas turbine cycles are concluded as three typical cycles of direct cycle, closed indirect cycle and open indirect cycle. Furthermore they are theoretically converted to three Brayton cycles of helium, nitrogen and air. Those three types of Brayton cycles are thermodynamically analyzed and optimized. The results show that the variety of gas affects the cycle pressure ratio more significantly than other cycle parameters, however, the optimized cycle efficiencies of the three Brayton cycles are almost the same. In addition, the turbomachines which are required for the three optimized Brayton cycles are aerodynamically analyzed and compared and their fundamental characteristics are obtained. Helium turbocompressor has lower stage pressure ratio and more stage number than those for nitrogen and air machines, while helium and nitrogen turbocompressors have shorter blade length than that for air machine