WorldWideScience

Sample records for wind-turbine-generator rotor-blade concepts

  1. Superconducting Wind Turbine Generators

    Directory of Open Access Journals (Sweden)

    Yunying Pan

    2016-08-01

    Full Text Available Wind energy is well known as a renewable energy because its clean and less polluted characteristic, which is the foundation of development modern wind electricity. To find more efficient wind turbine is the focus of scientists around the world. Compared from conventional wind turbines, superconducting wind turbine generators have advantages at zero resistance, smaller size and lighter weight. Superconducting wind turbine will inevitably become the main trends in this area. This paper intends to introduce the basic concept and principle of superconductivity, and compare form traditional wind turbine to obtain superiority, then to summary three proposed machine concept.While superconductivity have difficulty  in modern technology and we also have proposed some challenges in achieving superconducting wind turbine finally.

  2. Demonstration of an elastically coupled twist control concept for tilt rotor blade application

    Science.gov (United States)

    Lake, R. C.; Nixon, M. W.; Wilbur, M. L.; Singleton, J. D.; Mirick, P. H.

    1994-01-01

    The purpose of this Note is to present results from an analytic/experimental study that investigated the potential for passively changing blade twist through the use of extension-twist coupling. A set of composite model rotor blades was manufactured from existing blade molds for a low-twist metal helicopter rotor blade, with a view toward establishing a preliminary proof concept for extension-twist-coupled rotor blades. Data were obtained in hover for both a ballasted and unballasted blade configuration in sea-level atmospheric conditions. Test data were compared with results obtained from a geometrically nonlinear analysis of a detailed finite element model of the rotor blade developed in MSC/NASTRAN.

  3. Comparison of Megawatt-Class Permanent Magnet Wind Turbine Generator Concepts

    DEFF Research Database (Denmark)

    Henriksen, Matthew Lee; Jensen, Bogi Bech

    2012-01-01

    the differences in cost, efficiency, and mass of each drivetrain solution, and these are in turn related to the cost of energy. Based on the initial criteria of the study, the results favor geared concepts over direct-drive. The effects of varying several parameters are then explored in order to see what changes...... in availability, cost of structural mass, and OPEX would make the direct-drive concept favorable. It is concluded that if the cost of structural mass can be controlled, and availability/ OPEX advantages of around 2% and 40% respectively can be achieved, the cost of energy comparison may begin to favor directdrive...

  4. Superconducting Wind Turbine Generators

    DEFF Research Database (Denmark)

    Mijatovic, Nenad

    A HTS machine could be a way to address some of the technical barriers offshore wind energy is about to face. Due to the superior power density of HTS machines, this technology could become a milestone on which many, including the wind industry, will rely in the future. The work presented...... in this thesis is a part of a larger endeavor, the Superwind project that focused on identifying the potentials that HTS machines could offer to the wind industry and addressing some of the challenges in the process. In order to identify these challenges, I have design and constructed a HTS machine experimental...... setup which is made to serve as precursor, leading towards an optimized HTS machine concept proposed for wind turbines. In part, the work presented in this thesis will focus on the description of the experimental setup and reasoning behind the choices made during the design. The setup comprises from...

  5. Superconducting wind turbine generators

    DEFF Research Database (Denmark)

    Mijatovic, Nenad

    cryostat design, where a concept with 20 W of heat transfer is achieved. Following the setup description, the focus turns to the electromagnetic design of the HTS machine. Particularly, an approach to increase the performance of HTS coils and the influence of the armature reaction to the HTS field winding...... magnetic characteristic with respect to the critical current. I have showed that the potential for the reduction of HTS conductor can be significant, if the coils are placed strategically, whereby the coils wound with BSCCO performed 40% better depending on the placement in the field winding. The 2G coils...... were less sensitive to the placement which made them particularly useful for high magnetic field regions in the eld winding. The second design approach proposed and tested was to use multiple current supplies which allowed each coil to operate close to its critical current. I have demonstrated...

  6. Large superconducting wind turbine generators

    DEFF Research Database (Denmark)

    Abrahamsen, Asger Bech; Magnusson, Niklas; Jensen, Bogi Bech

    2012-01-01

    and the rotation speed is lowered in order to limit the tip speed of the blades. The ability of superconducting materials to carry high current densities with very small losses might facilitate a new class of generators operating with an air gap flux density considerably higher than conventional generators...... and thereby having a smaller size and weight [1, 2]. A 5 MW superconducting wind turbine generator forms the basics for the feasibility considerations, particularly for the YBCO and MgB2 superconductors entering the commercial market. Initial results indicate that a 5 MW generator with an active weight of 34...

  7. Site-optimization of wind turbine generators

    Energy Technology Data Exchange (ETDEWEB)

    Wolff, T.J. de; Thillerup, J. [Nordtank Energy Group, Richmond, VA (United States)

    1997-12-31

    The Danish Company Nordtank is one of the pioneers within the wind turbine industry. Since 1981 Nordtank has installed worldwide more than 2500 wind turbine generators with a total name plate capacity that is exceeding 450 MW. The opening up of new and widely divergent markets has demanded an extremely flexible approach towards wind turbine construction. The Nordtank product range has expanded considerable in recent years, with the main objective to develop wind energy conversion machines that can run profitable in any given case. This paper will describe site optimization of Nordtank wind turbines. Nordtank has developed a flexible design concept for its WTGs in the 500/750 kW range, in order to offer the optimal WTG solution for any given site and wind regime. Through this flexible design, the 500/750 turbine line can adjust the rotor diameter, tower height and many other components to optimally fit the turbine to each specific project. This design philosophy will be illustrated with some case histories of recently completed projects.

  8. Microprocessor control of a wind turbine generator

    Science.gov (United States)

    Gnecco, A. J.; Whitehead, G. T.

    1978-01-01

    This paper describes a microprocessor based system used to control the unattended operation of a wind turbine generator. The turbine and its microcomputer system are fully described with special emphasis on the wide variety of tasks performed by the microprocessor for the safe and efficient operation of the turbine. The flexibility, cost and reliability of the microprocessor were major factors in its selection.

  9. Development of superconducting wind turbine generators

    DEFF Research Database (Denmark)

    Jensen, Bogi Bech; Mijatovic, Nenad; Abrahamsen, Asger Bech

    2013-01-01

    In this paper, the commercial activities in the field of superconducting machines, particularly superconducting wind turbine generators, are reviewed and presented. Superconducting generators have the potential to provide a compact and light weight drive train at high torques and slow rotational...... speeds, because high magnetic fields can be produced by coils with very little loss. Three different superconducting wind turbine generator topologies have been proposed by three different companies. One is based on low temperature superconductors; one is based on high temperature superconductors......; and one is a fully superconducting generator based on MgB2. It is concluded that there is large commercial interest in superconducting machines, with an increasing patenting activity. Such generators are, however, not without their challenges. The superconductors have to be cooled down to somewhere...

  10. Development of Superconducting Wind Turbine Generators

    DEFF Research Database (Denmark)

    Jensen, Bogi Bech; Mijatovic, Nenad; Abrahamsen, Asger Bech

    2012-01-01

    In this paper the commercial activities in the field of superconducting machines, particularly superconducting wind turbine generators, are reviewed and presented. Superconducting generators have the potential to provide a compact and light weight drive train at high torques and slow rotational...... speeds, because high magnetic fields can be produced by coils with very little loss. Three different superconducting wind turbine generator topologies have been proposed by three different companies. One is based on low temperature superconductors (LTS); one is based on high temperature superconductors...... (HTS); and one is a fully superconducting generator based on MgB2. It is concluded that there is large commercial interest in superconducting machines, with an increasing patenting activity. Such generators are however not without their challenges. The superconductors have to be cooled down...

  11. Trends in Wind Turbine Generator Systems

    DEFF Research Database (Denmark)

    Polinder, Henk; Ferreira, Jan Abraham; Jensen, Bogi Bech

    2013-01-01

    This paper reviews the trends in wind turbine generator systems. After discussing some important requirements and basic relations, it describes the currently used systems: the constant speed system with squirrel-cage induction generator, and the three variable speed systems with doubly fed...... induction generator (DFIG), with gearbox and fully rated converter, and direct drive (DD). Then, possible future generator systems are reviewed. Hydraulic transmissions are significantly lighter than gearboxes and enable continuously variable transmission, but their efficiency is lower. A brushless DFIG...

  12. Model 0A wind turbine generator FMEA

    Science.gov (United States)

    Klein, William E.; Lalli, Vincent R.

    1989-01-01

    The results of Failure Modes and Effects Analysis (FMEA) conducted for the Wind Turbine Generators are presented. The FMEA was performed for the functional modes of each system, subsystem, or component. The single-point failures were eliminated for most of the systems. The blade system was the only exception. The qualitative probability of a blade separating was estimated at level D-remote. Many changes were made to the hardware as a result of this analysis. The most significant change was the addition of the safety system. Operational experience and need to improve machine availability have resulted in subsequent changes to the various systems which are also reflected in this FMEA.

  13. Magnet Free Generators - 3rd Generation Wind Turbine Generators

    DEFF Research Database (Denmark)

    Jensen, Bogi Bech; Mijatovic, Nenad; Henriksen, Matthew Lee

    2013-01-01

    This paper presents an introduction to superconducting wind turbine generators, which are often referred to as 3rd generation wind turbine generators. Advantages and challenges of superconducting generators are presented with particular focus on possible weight and efficiency improvements. A comp...

  14. Status of the Southern California Edison Company 3 MW Wind Turbine Generator (WTG) demonstration project

    Science.gov (United States)

    Scheffler, R. L.

    1979-01-01

    To demonstrate the concept of utility scale electricity production from a high wind energy resource, a program was initiated to construct and test a 3 megawatt (3,000 kW) Schachle wind turbine generator near Palm Springs, California. The background and current status of this program are presented along with a summary of future planned program activities.

  15. Optimal Excitation Controller Design for Wind Turbine Generator

    Directory of Open Access Journals (Sweden)

    A. K. Boglou

    2011-01-01

    Full Text Available An optimal excitation controller design based on multirate-output controllers (MROCs having a multirate sampling mechanismwith different sampling period in each measured output of the system is presented. The proposed H∞ -control techniqueis applied to the discrete linear open-loop system model which represents a wind turbine generator supplying an infinite busthrough a transmission line.

  16. Discussion on mass concrete construction of wind turbine generator foundation

    Science.gov (United States)

    Shang, Liang; Wu, Chaoxiang; Yin, Xiaoyong

    2018-04-01

    Wind power is one of the main power sources currently. China has rich wind power resources, wind power plants are developed faster and faster. However, China wind power construction started late, which is lack of relevant experience technology. It is easy to produce quality problems. The key to the construction quality of wind power plant is the construction quality of mass concrete construction. Therefore, construction technology and quality control of wind turbine generator foundation mass concrete are discussed and analyzed in the paper.

  17. Multiple piece turbine rotor blade

    Science.gov (United States)

    Jones, Russell B; Fedock, John A

    2013-05-21

    A multiple piece turbine rotor blade with a shell having an airfoil shape and secured between a spar and a platform with the spar including a tip end piece. a snap ring fits around the spar and abuts against the spar tip end piece on a top side and abuts against a shell on the bottom side so that the centrifugal loads from the shell is passed through the snap ring and into the spar and not through a tip cap dovetail slot and projection structure.

  18. 5MW Direct Drive Wind Turbine Generator Design

    DEFF Research Database (Denmark)

    Zaidi, Arsalan; Senn, Lucile; Ortega, Iratxe

    2012-01-01

    A 5MW direct drive offshore wind turbine generator was studied and simulated using Vector Fields OPERA. This software allows calculation of the flux density, force, torque, and eddy currents in the machine at different rotor positions. Based on the data obtained from the model, initial assumptions...... for the suitable machine are listed and the modelling process presented. The model of the generator was improved by changing design parameters, e.g the position of the magnets or fitting additional I-Cores, and analyse the effect of it....

  19. Methods and apparatus for cooling wind turbine generators

    Science.gov (United States)

    Salamah, Samir A [Niskayuna, NY; Gadre, Aniruddha Dattatraya [Rexford, NY; Garg, Jivtesh [Schenectady, NY; Bagepalli, Bharat Sampathkumaran [Niskayuna, NY; Jansen, Patrick Lee [Alplaus, NY; Carl, Jr., Ralph James

    2008-10-28

    A wind turbine generator includes a stator having a core and a plurality of stator windings circumferentially spaced about a generator longitudinal axis. A rotor is rotatable about the generator longitudinal axis, and the rotor includes a plurality of magnetic elements coupled to the rotor and cooperating with the stator windings. The magnetic elements are configured to generate a magnetic field and the stator windings are configured to interact with the magnetic field to generate a voltage in the stator windings. A heat pipe assembly thermally engaging one of the stator and the rotor to dissipate heat generated in the stator or rotor.

  20. Structural modeling for multicell composite rotor blades

    Science.gov (United States)

    Rehfield, Lawrence W.; Atilgan, Ali R.

    1987-01-01

    Composite material systems are currently good candidates for aerospace structures, primarily for the design flexibility they offer, i.e., it is possible to tailor the material and manufacturing approach to the application. A working definition of elastic or structural tailoring is the use of structural concept, fiber orientation, ply stacking sequence, and a blend of materials to achieve specific performance goals. In the design process, choices of materials and dimensions are made which produce specific response characteristics, and which permit the selected goals to be achieved. Common choices for tailoring goals are preventing instabilities or vibration resonances or enhancing damage tolerance. An essential, enabling factor in the design of tailored composite structures is structural modeling that accurately, but simply, characterizes response. The objective of this paper is to present a new multicell beam model for composite rotor blades and to validate predictions based on the new model by comparison with a finite element simulation in three benchmark static load cases.

  1. Short circuit signatures from different wind turbine generator types

    DEFF Research Database (Denmark)

    Martinez, Jorge; Kjær, Philip C.; Rodriguez, Pedro

    2011-01-01

    Modern wind power plants are required and designed to ride through faults in the network, subjected to the fault clearance and following grid code demands. Beside voltage support during faults, the wind turbine fault current contribution is important to establish the correct settings for the relay...... of the protections. The following wind turbine generator during faults have been studied: (i) induction generator, (ii) induction generator with variable rotor resistance (iii) converter-fed rotor (often referred to as DFIG) and (iv) full scale converter. To make a clear comparison and performance analysis during...... faults, and the consequent effects on substation protections, the aforementioned configurations have been simulated using PSCAD/EMTDC, with the same power plant configuration, electrical grid and generator data. Additionally, a comparison of these wind turbine technologies with a conventional power plant...

  2. Conceptual design of the 7 megawatt Mod-5B wind turbine generator

    Science.gov (United States)

    Douglas, R. R.

    1982-01-01

    Similar to MOD-2, the MOD-5B wind turbine generator system is designed for the sole purpose of providing electrical power for distribution by a major utility network. The objectives of the MOD-2 and MOD-5B programs are essentially identical with one important exception; the cost-of-electricity (COE) target is reduced from 4 cent/Kwhr on MOD-2 to 3 cent/Kwhr on MOD-5B, based on mid 1977 dollars and large quantity production. The MOD-5B concept studies and eventual concept selection confirmed that the program COE targets could not only be achieved but substantially bettered. Starting from the established MOD-2 technology as a base, this achievement resulted from a combination of concept changes, size changes, and design refinements. The result of this effort is a wind turbine system that can compete with conventional power generation over significant geographical areas, increasing commercial market potential by an order of magnitude.

  3. Mod-5A wind turbine generator program design report. Volume 4: Drawings and specifications, book 5

    Science.gov (United States)

    1984-01-01

    The design, development and analysis of the 7.3 MW MOD-5A wind turbine generator is documented. There are four volumes. This volume contains the drawings and specifications that were developed in preparation for building the MOD-5A wind turbine generator. Detail drawings of several assemblies and subassemblies are given. This is the fifth book of volume 4.

  4. An improved fuzzy synthetic condition assessment of a wind turbine generator system

    DEFF Research Database (Denmark)

    Li, H.; Hu, Y. G.; Yang, Chao

    2013-01-01

    This paper presents an improved fuzzy synthetic model that is based on a real-time condition assessment method of a grid-connected wind turbine generator system (WTGS) to improve the operational reliability and optimize the maintenance strategy. First, a condition assessment framework is proposed...... by analyzing the monitoring data of the WTGS. An improved fuzzy synthetic condition assessment method is then proposed that utilizes the concepts of deterioration degree, dynamic limited values and variable weight calculations of the assessment indices. Finally, by using on-line monitoring data of an actual...... 850 kW WTGS, real-time condition assessments are performed that utilize the proposed fuzzy synthetic method; the model’s effectiveness is also compared to a traditional fuzzy assessment method in which constant limited values and constant weights are adopted. The results show that the condition...

  5. Aircraft rotor blade with passive tuned tab

    Science.gov (United States)

    Campbell, T. G. (Inventor)

    1985-01-01

    A structure for reducing vibratory airloading in a rotor blade with a leading edge and a trailing edge includes a cut out portion at the trailing edge. A substantially wedge shaped cross section, inertially deflectable tab, also with a leading edge and a trailing edge is pivotally mounted in the cut out portion. The trailing edge of the tab may move above and below the rotor blade. A torsion strap applies force against the tab when the trailing edge of the tab is above and below the rotor blade. A restraining member is slidably movable along the torsion strap to vary torsional biasing force supplied by the torsion bar to the tab. A plurality of movable weights positioned between plates vary a center of gravity of the tab. Skin of the tab is formed from unidirectional graphite and fiberglass layers. Sliders coupled with a pinned degree of freedom at rod eliminate bending of tab under edgewise blade deflection.

  6. Engineering handbook on the atmospheric environmental guidelines for use in wind turbine generator development

    Science.gov (United States)

    Frost, W.; Long, B. H.; Turner, R. E.

    1978-01-01

    The guidelines are given in the form of design criteria relative to wind speed, wind shear, turbulence, wind direction, ice and snow loading, and other climatological parameters which include rain, hail, thermal effects, abrasive and corrosive effects, and humidity. This report is a presentation of design criteria in an engineering format which can be directly input to wind turbine generator design computations. Guidelines are also provided for developing specialized wind turbine generators or for designing wind turbine generators which are to be used in a special region of the United States.

  7. Simple theoretical models for composite rotor blades

    Science.gov (United States)

    Valisetty, R. R.; Rehfield, L. W.

    1984-01-01

    The development of theoretical rotor blade structural models for designs based upon composite construction is discussed. Care was exercised to include a member of nonclassical effects that previous experience indicated would be potentially important to account for. A model, representative of the size of a main rotor blade, is analyzed in order to assess the importance of various influences. The findings of this model study suggest that for the slenderness and closed cell construction considered, the refinements are of little importance and a classical type theory is adequate. The potential of elastic tailoring is dramatically demonstrated, so the generality of arbitrary ply layup in the cell wall is needed to exploit this opportunity.

  8. Simulation of Small Wind Turbine Generation System Using Ring Winding Slotless PMSG by FEM

    OpenAIRE

    徳永, 翔平; 袈裟丸, 勝己; Tokunaga, Shohei; Kesamaru, Katsumi

    2011-01-01

    This paper describes a novel small wind turbine generation system with ring winding slotless PMSG. To reduce cogging torque, ring winding PM generator is used for a wind turbine generator. Using finite element analysis, the characteristics of slotless PMSGs are elucidated and the dynamic performance of the proposed system with MPPT control is represented. In this paper, the constant wind test and the quasi-natural wind test are conducted. The results of these tests indicate the proposed syste...

  9. Assessment Report on Innovative Rotor Blades (MAREWINT WP1,D1.3)

    DEFF Research Database (Denmark)

    McGugan, Malcolm; Leble, Vladimir; Pereira, Gilmar Ferreira

    The offshore wind energy industry faces many challenges in the short to medium term if it is to meet the ambitions of the global community for sustainable energy supply in the future. Not least among these challenges is the issue of rotor blades. Innovative design for “smart” rotor blades...... the innovative concept development for wind turbine blades. This covers models and experiments with damage measurement systems embedded within the composite material/structure and numerical methods investigating the effects of leading and trailing edge flaps on modifying the aerodynamic loads on the operating...... rotor....

  10. Flapping inertia for selected rotor blades

    Science.gov (United States)

    Berry, John D.; May, Matthew J.

    1991-01-01

    Aerodynamics of helicopter rotor systems cannot be investigated without consideration for the dynamics of the rotor. One of the principal properties of the rotor which affects the rotor dynamics is the inertia of the rotor blade about its root attachment. Previous aerodynamic investigation have been performed on rotor blades with a variety of planforms to determine the performance differences due to blade planform. The blades tested for this investigation have been tested on the U.S. Army 2 meter rotor test system (2MRTS) in the NASA Langley 14 by 22 foot subsonic tunnel for hover performance. This investigation was intended to provide fundamental information on the flapping inertia of five rotor blades with differing planforms. The inertia of the bare cuff and the cuff with a blade extension were also measured for comparison with the inertia of the blades. Inertia was determined using a swing testing technique, using the period of oscillation to determine the effective flapping inertia. The effect of damping in the swing test was measured and described. A comparison of the flapping inertials for rectangular and tapered planform blades of approximately the same mass showed the tapered blades to have a lower inertia, as expected.

  11. Conceptual design of a fixed-pitch wind turbine generator system rated at 400 kilowatts

    Science.gov (United States)

    Pintz, A.; Kasuba, R.; Spring, J.

    1984-01-01

    The design and cost aspects of a fixed pitch, 400 kW Wind Turbine Generator (WTG) concept are presented. Improvements in reliability and cost reductions were achieved with fixed pitch operation and by incorporating recent advances in WTG technology. The specifications for this WTG concept were as follows: (1) A fixed pitch, continuous wooden rotor was to be provided by the Gougeon Bros. Co. (2) An 8 leg hyperboloid tower that showed promise as a low cost structure was to be used. (3) Only commercially available components and parts that could be easily fabricated were to be considered. (4) Design features deemed desirable based on recent NASA research efforts were to be incorporated. Detailed costs and weight estimates were prepared for the second machine and a wind farm of 12 WTG's. The calculated cost of energy for the fixed pitch, twelve unit windfarm is 11.5 cents/kW hr not including the cost of land and access roads. The study shows feasibility of fixed pitch, intermediate power WTG operation.

  12. Wind Turbine Generator Efficiency Based on Powertrain Combination and Annual Power Generation Prediction

    Directory of Open Access Journals (Sweden)

    Dongmyung Kim

    2018-05-01

    Full Text Available Wind turbine generators are eco-friendly generators that produce electric energy using wind energy. In this study, wind turbine generator efficiency is examined using a powertrain combination and annual power generation prediction, by employing an analysis model. Performance testing was conducted in order to analyze the efficiency of a hydraulic pump and a motor, which are key components, and so as to verify the analysis model. The annual wind speed occurrence frequency for the expected installation areas was used to predict the annual power generation of the wind turbine generators. It was found that the parallel combination of the induction motors exhibited a higher efficiency when the wind speed was low and the serial combination showed higher efficiency when wind speed was high. The results of predicting the annual power generation considering the regional characteristics showed that the power generation was the highest when the hydraulic motors were designed in parallel and the induction motors were designed in series.

  13. Short Circuits of a 10 MW High Temperature Superconducting Wind Turbine Generator

    DEFF Research Database (Denmark)

    Song, Xiaowei (Andy); Liu, Dong; Polinder, Henk

    2016-01-01

    Direct drive high temperature superconducting (HTS) wind turbine generators have been proposed to tackle challenges for ever increasing wind turbine ratings. Due to smaller reactances in HTS generators, higher fault currents and larger transient torques could occur if sudden short circuits happen...... at generator terminals. In this paper, a finite element model that couples magnetic fields and the generator’s equivalent circuits is developed to simulate short circuit faults. Afterwards, the model is used to study the transient performance of a 10 MW HTS wind turbine generator under four different short...... that the short circuits pose great challenges to the generator, and careful consideration should be given to protect the generator. The results presented in this paper would be beneficial to the design, operation and protection of an HTS wind turbine generator....

  14. Short Circuits of a 10-MW High-Temperature Superconducting Wind Turbine Generator

    DEFF Research Database (Denmark)

    Song, Xiaowei (Andy); Liu, Dong; Polinder, Henk

    2017-01-01

    Direct Drive high-temperature superconducting (HTS) wind turbine generators have been proposed to tackle challenges for ever increasing wind turbine ratings. Due to smaller reactances in HTS generators, higher fault currents and larger transient torques could occur if sudden short circuits take...... place at generator terminals. In this paper, a finite element model that couples magnetic fields and the generator's equivalent circuits is developed to simulate short-circuit faults. Afterward, the model is used to study the transient performance of a 10-MW HTS wind turbine generator under four...... show that the short circuits pose great challenges to the generator, and careful consideration should be given to protect the generator. The findings presented in this paper would be beneficial to the design, operation and protection of an HTS wind turbine generator....

  15. Performance of a 3 kW wind turbine generator with variable pitch control system

    International Nuclear Information System (INIS)

    Nagai, Baku M.; Ameku, Kazumasa; Roy, Jitendro Nath

    2009-01-01

    A prototype 3 kW horizontal upwind type wind turbine generator of 4 m in diameter has been designed and examined under real wind conditions. The machine was designed based on the concept that even small wind turbines should have a variable pitch control system just as large wind turbines, especially in Japan where typhoons occur at least once a year. A characteristic of the machine is the use of a worm and gear system with a stepping motor installed in the center of the hub, and the rotational main shaft. The machine is constructed with no mechanical breaking system so as to avoid damage from strong winds. In a storm, the wind turbine is slowed down by adjusting the pitch angle and the maximum electrical load. Usually the machine is controlled at several stages depending on the rotational speed of the blades. Two control methods have been applied: the variable pitch angle, and regulation of the generator field current. The characteristics of the generator under each rotational speed and field current are first investigated in the laboratory. This paper describes the performances of the wind turbine in terms of the functions of wind turbine rotational speed, generated outputs, and its stability for wind speed changes. The expected performances of the machine have been confirmed under real wind conditions and compared with numerical simulation results. The wind turbine showed a power coefficient of 0.257 under the average wind speed of 7.3 m/s.

  16. A structural model for composite rotor blades and lifting surfaces

    Science.gov (United States)

    Rehfield, Lawrence W.; Atilgan, Ali R.

    1987-01-01

    Composite material systems are currently candidates for aerospace structures, primarily for the design flexibiity they offer i.e., it is possible to tailor the material and manufacturing approach to the application. Two notable examples are the wing of the Grumman/USAF/DARPA X-29 and rotor blades under development by the U.S.A. Aerostructures Directorate (AVSCOM), Langley Research Center. A working definition of elastic or structural tailoring is the use of structural concept, fiber orientation, ply stacking sequence, and a blend of materials to achieve specific performance goals. In the design process, choices of materials and dimensions are made which produce specific response characteristics which permit the selected goals to be achieved. Common choices for tailoring goals are preventing instabilities or vibration resonances or enhancing damage tolerance. An essential, enabling factor in the design of tailored composite structures is structural modeling that accurately, but simply, characterizes response. The objective of this paper is to improve the single-cell beam model for composite rotor blades or lifting surfaces and to demonstrate its usefullness in applications.

  17. Mod-5A wind turbine generator program design report. Volume 4: Drawings and specifications, book 4

    Science.gov (United States)

    1984-01-01

    The design, development and analysis of the 7.3 MW MOD-5A wind turbine generator are documented. There are four volumes. This volume contains the drawings and specifications that were developed in preparation for building the MOD-5A wind turbine generator. This volume contains 5 books of which this is the fourth, providing drawings 47A380128 through 47A387125. In addition to the parts listing and where-used list, the logic design of the controller software and the code listing of the controller software are provided. Also given are the aerodynamic profile coordinates.

  18. Mod-5A wind turbine generator program design report. Volume 4: Drawings and specifications, book 2

    Science.gov (United States)

    1984-01-01

    The design, development and analysis of the 7.3 MW MOD-5A wind turbine generator is documented. There are four volumes. This volume contains the drawings and specifications that were developed in preparation for building the MOD-5A wind turbine generator. This is the second book of volume four. Some of the items it contains are specs for the emergency shutdown panel, specs for the simulator software, simulator hardware specs, site operator terminal requirements, control data system requirements, software project management plan, elastomeric teeter bearing requirement specs, specs for the controls electronic cabinet, and specs for bolt pretensioning.

  19. Mod-5A Wind Turbine Generator Program Design Report. Volume 4: Drawings and Specifications, Book 1

    Science.gov (United States)

    1984-01-01

    The design, development and analysis of the 7.3 MW MOD-5A wind turbine generator is documented. Volume 4 contains the drawings and specifications that were developed in preparation for building the MOD-5A wind turbine generator. This is the first of five books of volume four. It contains structural design criteria, generator step-up transformer specs, specs for design, fabrication and testing of the system, specs for the ground control enclosure, systems specs, slip ring specs, and control system specs.

  20. Design optimization for active twist rotor blades

    Science.gov (United States)

    Mok, Ji Won

    This dissertation introduces the process of optimizing active twist rotor blades in the presence of embedded anisotropic piezo-composite actuators. Optimum design of active twist blades is a complex task, since it involves a rich design space with tightly coupled design variables. The study presents the development of an optimization framework for active helicopter rotor blade cross-sectional design. This optimization framework allows for exploring a rich and highly nonlinear design space in order to optimize the active twist rotor blades. Different analytical components are combined in the framework: cross-sectional analysis (UM/VABS), an automated mesh generator, a beam solver (DYMORE), a three-dimensional local strain recovery module, and a gradient based optimizer within MATLAB. Through the mathematical optimization problem, the static twist actuation performance of a blade is maximized while satisfying a series of blade constraints. These constraints are associated with locations of the center of gravity and elastic axis, blade mass per unit span, fundamental rotating blade frequencies, and the blade strength based on local three-dimensional strain fields under worst loading conditions. Through pre-processing, limitations of the proposed process have been studied. When limitations were detected, resolution strategies were proposed. These include mesh overlapping, element distortion, trailing edge tab modeling, electrode modeling and foam implementation of the mesh generator, and the initial point sensibility of the current optimization scheme. Examples demonstrate the effectiveness of this process. Optimization studies were performed on the NASA/Army/MIT ATR blade case. Even though that design was built and shown significant impact in vibration reduction, the proposed optimization process showed that the design could be improved significantly. The second example, based on a model scale of the AH-64D Apache blade, emphasized the capability of this framework to

  1. Monitoring and economics of a 60 kW wind turbine generator on a pig farm in Scotland

    International Nuclear Information System (INIS)

    Saluja, G.S.

    1990-01-01

    Low cost monitoring of a 60 kW wind turbine generator connected to an intensive pig farm in the Grampian area of Scotland is described. A method of calculating the economic implications of installing a small grid-connected wind turbine generator at a farm is based on monitored data, electricity bills and energy production is proposed. (author)

  2. Mod-5A wind turbine generator program design report. Volume 3: Final design and system description, book 1

    Science.gov (United States)

    1984-01-01

    The design, development and analysis of the 7.3 MW MOD-5A wind turbine generator is documented. Volume 3, book 1 describes the performance and characteristics of the MOD-5A wind turbine generator in its final configuration. Each subsystem - the rotor, drivetrain, nacelle, tower and foundation is described in detail.

  3. Incorporation of Finite Element Analysis into Annual Energy Loss Estimation for Permanent Magnet Wind Turbine Generators

    DEFF Research Database (Denmark)

    Henriksen, Matthew Lee; Jensen, Bogi Bech

    2013-01-01

    Several methods of estimating the annual energy losses for wind turbine generators are investigated in this paper. Utilizing a high amount of transient simulations with motion is first demonstrated. Usage of a space-time transformation for prediction of iron losses is also explored. The methods, ...

  4. A testing procedure for wind turbine generators based on the power grid statistical model

    DEFF Research Database (Denmark)

    Farajzadehbibalan, Saber; Ramezani, Mohammad Hossein; Nielsen, Peter

    2017-01-01

    In this study, a comprehensive test procedure is developed to test wind turbine generators with a hardware-in-loop setup. The procedure employs the statistical model of the power grid considering the restrictions of the test facility and system dynamics. Given the model in the latent space...

  5. Short Circuits of a 10 MW High Temperature Superconducting Wind Turbine Generator

    NARCIS (Netherlands)

    Song, X.; Polinder, H.; Liu, D.; Mijatovic, Nenad; Holbøll, Joachim; Jensen, Bogi Bech

    Direct drive high temperature superconducting (HTS) wind turbine generators have been proposed to tackle challenges for ever increasing wind turbine ratings. Due to smaller reactances in HTS generators, higher fault currents and larger transient torques could occur if sudden short circuits happen at

  6. Wind Turbine Generator System Safety and Function Test Report for the Entegrity EW50 Wind Turbine

    Energy Technology Data Exchange (ETDEWEB)

    Smith, J.; Huskey, A.; Jager, D.; Hur, J.

    2012-11-01

    This report summarizes the results of a safety and function test that NREL conducted on the Entegrity EW50 wind turbine. This test was conducted in accordance with the International Electrotechnical Commissions' (IEC) standard, Wind Turbine Generator System Part 2: Design requirements for small wind turbines, IEC 61400-2 Ed.2.0, 2006-03.

  7. Executive summary: Mod-1 wind turbine generator analysis and design report

    Science.gov (United States)

    1979-01-01

    Activities leading to the detail design of a wind turbine generator having a nominal rating of 1.8 megawatts are reported. Topics covered include (1) system description; (2) structural dynamics; (3) stability analysis; (4) mechanical subassemblies design; (5) power generation subsystem; and (6) control and instrumentation subsystem.

  8. MOD-1 Wind Turbine Generator Analysis and Design Report, Volume 2

    Science.gov (United States)

    1979-01-01

    The MOD-1 detail design is appended. The supporting analyses presented include a parametric system trade study, a verification of the computer codes used for rotor loads analysis, a metal blade study, and a definition of the design loads at each principal wind turbine generator interface for critical loading conditions. Shipping and assembly requirements, composite blade development, and electrical stability are also discussed.

  9. Mod-1 wind turbine generator analysis and design report, volume 1

    Science.gov (United States)

    1979-01-01

    The activities leading to the completion of detail design of the MOD-1 wind turbine generator are described. Emphasis is placed on the description of the design as it finally evolved. However, the steps through which the design progressed are also traced in order to understand the major design decisions.

  10. Composite rotor blades for large wind energy installations

    Science.gov (United States)

    Kussmann, A.; Molly, J.; Muser, D.

    1980-01-01

    The design of large wind power systems in Germany is reviewed with attention given to elaboration of the total wind energy system, aerodynamic design of the rotor blade, and wind loading effects. Particular consideration is given to the development of composite glass fiber/plastic or carbon fiber/plastic rotor blades for such installations.

  11. Composite rotor blades for large wind energy installations

    Energy Technology Data Exchange (ETDEWEB)

    Kussmann, A; Molly, J P; Muser, D

    1979-06-01

    The design of large wind power systems in Germany is reviewed with attention given to elaboration of the total wind energy system, aerodynamic design of the rotor blade, and wind loading effects. Particular consideration is given to the development of composite glass fiber/plastic or carbon fiber/plastic rotor blades for such installations.

  12. Geometrically exact nonlinear analysis of pre-twisted composite rotor blades

    Directory of Open Access Journals (Sweden)

    Li'na SHANG

    2018-02-01

    Full Text Available Modeling of pre-twisted composite rotor blades is very complicated not only because of the geometric non-linearity, but also because of the cross-sectional warping and the transverse shear deformation caused by the anisotropic material properties. In this paper, the geometrically exact nonlinear modeling of a generalized Timoshenko beam with arbitrary cross-sectional shape, generally anisotropic material behavior and large deflections has been presented based on Hodges’ method. The concept of decomposition of rotation tensor was used to express the strain in the beam. The variational asymptotic method was used to determine the arbitrary warping of the beam cross section. The generalized Timoshenko strain energy was derived from the equilibrium equations and the second-order asymptotically correct strain energy. The geometrically exact nonlinear equations of motion were established by Hamilton’s principle. The established modeling was used for the static and dynamic analysis of pre-twisted composite rotor blades, and the analytical results were validated based on experimental data. The influences of the transverse shear deformation on the pre-twisted composite rotor blade were investigated. The results indicate that the influences of the transverse shear deformation on the static deformation and the natural frequencies of the pre-twisted composite rotor blade are related to the length to chord ratio of the blade. Keywords: Geometrically exact, Nonlinear, Pre-twisted composite blade, Transverse shear deformation, Variational asymptotic, Warping

  13. 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.

  14. Analyzing the requirements for mass production of small wind turbine generators

    Science.gov (United States)

    Anuskiewicz, T.; Asmussen, J.; Frankenfield, O.

    Mass producibility of small wind turbine generators to give manufacturers design and cost data for profitable production operations is discussed. A 15 kW wind turbine generator for production in annual volumes from 1,000 to 50,000 units is discussed. Methodology to cost the systems effectively is explained. The process estimate sequence followed is outlined with emphasis on the process estimate sheets compiled for each component and subsystem. These data enabled analysts to develop cost breakdown profiles crucial in manufacturing decision-making. The appraisal also led to various design recommendations including replacement of aluminum towers with cost effective carbon steel towers. Extensive cost information is supplied in tables covering subassemblies, capital requirements, and levelized energy costs. The physical layout of the plant is depicted to guide manufacturers in taking advantage of the growing business opportunity now offered in conjunction with the national need for energy development.

  15. Output Power Control of Wind Turbine Generator by Pitch Angle Control using Minimum Variance Control

    Science.gov (United States)

    Senjyu, Tomonobu; Sakamoto, Ryosei; Urasaki, Naomitsu; Higa, Hiroki; Uezato, Katsumi; Funabashi, Toshihisa

    In recent years, there have been problems such as exhaustion of fossil fuels, e. g., coal and oil, and environmental pollution resulting from consumption. Effective utilization of renewable energies such as wind energy is expected instead of the fossil fuel. Wind energy is not constant and windmill output is proportional to the cube of wind speed, which cause the generated power of wind turbine generators (WTGs) to fluctuate. In order to reduce fluctuating components, there is a method to control pitch angle of blades of the windmill. In this paper, output power leveling of wind turbine generator by pitch angle control using an adaptive control is proposed. A self-tuning regulator is used in adaptive control. The control input is determined by the minimum variance control. It is possible to compensate control input to alleviate generating power fluctuation with using proposed controller. The simulation results with using actual detailed model for wind power system show effectiveness of the proposed controller.

  16. 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...

  17. Mod-5A wind turbine generator program design report. Volume 4: Drawings and specifications, book 3

    Science.gov (United States)

    1984-01-01

    The design, development and analysis of the 7.3 MW MOD-5A wind turbine generator is documented. This volume contains the drawings and specifications developed for the final design. This volume is divided into 5 books of which this is the third, containing drawings 47A380074 through 47A380126. A full breakdown parts listing is provided as well as a where used list.

  18. Control design and performance analysis of a 6 MW wind turbine-generator

    Science.gov (United States)

    Murdoch, A.; Winkelman, J. R.; Javid, S. H.; Barton, R. S.

    1983-01-01

    This paper discusses an approach to the modeling and performance for the preliminary design phase of a large (6.2 MW) horizontal axis wind turbine generator (WTG). Two control philosophies are presented, both of which are based on linearized models of the WT mechanical and electrical systems. The control designs are compared by showing the performance through detailed non-linear time simulation. The disturbances considered are wind gusts, and electrical faults near the WT terminals.

  19. Redesign of steam turbine rotor blades and rotor packages – Environmental analysis within systematic eco-design approach

    International Nuclear Information System (INIS)

    Baran, Jolanta

    2016-01-01

    Highlights: • Systematic approach to eco-design of steam turbine rotor blades was applied. • Eco-innovative solutions are based on structural and technological change. • At the stage of detailed design the variants were analyzed using LCA. • Main achieved benefits: energy and material savings, lower environmental impact. • Benefits related to the possible scale of the solution practical application. - Abstract: Eco-design of steam turbine blades could be one of the possibilities of decreasing the environmental impact of energy systems based on turbines. The paper investigates the eco-design approach to elaboration of the rotor blades and packages. The purpose is to present the course of eco-design of the rotor blades and the rotor packages taking account of eco-design assumptions, solutions and the concept itself. The following eco-design variants of the rotor blades and the rotor packages are considered: elements of the rotor blades made separately (baseline variant of the rotor blades); elements of the rotor blades made of one piece of material; blades in packages made separately and welded (baseline variant of the rotor packages); packages milled as integral elements. At the stage of detailed design, the Life Cycle Assessment (LCA) is performed in relation to a functional unit – the rotor blades and packages ready for installation in a steam turbine, which is the stage of the turbine. The obtained results indicate that eco-innovative solutions for the turbine blades and packages could be achieved through structural and technological changes. Applying new solutions of the rotor blades may produce the following main benefits: 3.3% lower use of materials, 29.4% decrease in energy consumption at the manufacturing stage, 7.7% decrease in the environmental impact in the life cycle. In relation to the rotor packages, the following main benefits may be achieved: 20.5% lower use of materials, 25.0% decrease in energy consumption at the production stage, 16

  20. Design Preliminaries for Direct Drive under Water Wind Turbine Generator

    DEFF Research Database (Denmark)

    Leban, Krisztina Monika; Ritchie, Ewen; Argeseanu, Alin

    2012-01-01

    This paper focuses on the preliminary design process of a 20 MW electric generator. The application calls for an offshore, vertical axis, direct drive wind turbine. Arguments for selecting the type of electric machine for the application are presented and discussed. Comparison criteria for deciding...... on a type of machine are listed. Additional constraints emerging from the direct drive, vertical axis concepts are considered. General rules and a preliminary algorithm are discussed for the machine selected to be most suitable for the imposed conditions....

  1. Helicopter Rotor Blade Monitoring using Autonomous Wireless Sensor Network

    NARCIS (Netherlands)

    Sanchez Ramirez, Andrea; Loendersloot, Richard; Tinga, Tiedo; Basu, B.

    2013-01-01

    The advancement on Wireless Sensor Networks for vibration monitoring presents important possibilities for helicopter rotor health and usage monitoring. While main rotor blades account for the main source of lift for helicopters, rotor induced vibration establishes an important source for

  2. Rotor blade online monitoring and fault diagnosis technology research

    DEFF Research Database (Denmark)

    Tesauro, Angelo; Pavese, Christian; Branner, Kim

    Rotor blade online monitoring and fault diagnosis technology is an important way to find blade failure mechanisms and thereby improve the blade design. Condition monitoring of rotor blades is necessary in order to ensure the safe operation of the wind turbine, make the maintenance more economical...... of the rotor, icing and lightning. Research is done throughout the world in order to develop and improve such measurement systems. Commercial hardware and software available for the described purpose is presented in the report....

  3. Piezoelectric actuation of helicopter rotor blades

    Science.gov (United States)

    Lieven, Nicholas A. J.

    2001-07-01

    The work presented in this paper is concerned with the application of embedded piezo-electric actuators in model helicopter rotor blades. The paper outlines techniques to define the optimal location of actuators to excite particular modes of vibration whilst the blade is rotating. Using composite blades the distribution of strain energy is defined using a Finite Element model with imposed rotor-dynamic and aerodynamics loads. The loads are specified through strip theory to determine the position of maximum bending moment and thus the optimal location of the embedded actuators. The effectiveness of the technique is demonstrated on a 1/4 scale fixed cyclic pitch rotor head. Measurement of the blade displacement is achieved by using strain gauges. In addition a redundant piezo-electric actuator is used to measure the blades' response characteristics. The addition of piezo-electric devices in this application has been shown to exhibit adverse aeroelastic effects, such as counter mass balancing and increased drag. Methods to minimise these effects are suggested. The outcome of the paper is a method for defining the location and orientation of piezo-electric devices in rotor-dynamic applications.

  4. Wind Turbine Generator System Power Performance Test Report for the ARE442 Wind Turbine

    Energy Technology Data Exchange (ETDEWEB)

    van Dam, J.; Jager, D.

    2010-02-01

    This report summarizes the results of a power performance test that NREL conducted on the ARE 442 wind turbine. This test was conducted in accordance with the International Electrotechnical Commission's (IEC) standard, Wind Turbine Generator Systems Part 12: Power Performance Measurements of Electricity Producing Wind Turbines, IEC 61400-12-1 Ed.1.0, 2005-12. However, because the ARE 442 is a small turbine as defined by IEC, NREL also followed Annex H that applies to small wind turbines. In these summary results, wind speed is normalized to sea-level air density.

  5. Characterization of a Power Electronic Grid Simulator for Wind Turbine Generator Compliance Testing

    DEFF Research Database (Denmark)

    Glasdam, Jakob Bærholm; Gevorgian, V.; Wallen, R.

    2014-01-01

    This paper presents the commissioning results and testing capabilities of a multi-megawatt power electronic grid simulator situated in National Renewable Energy Laboratory’s (NREL’s) new testing facility. The commissioning is done using a commercial type 4 multi-megawatt sized wind turbine...... generator (WTG) installed in NREL’s new 5 MW dynamometer and a kilowatt sized type 1 WTG connected to the existing 2.5 MW dynamometer at NREL. The paper demonstrates the outstanding testing capability of the grid simulator and its application in the grid code compliance evaluation of WTGs including balanced...

  6. Power train analysis for the DOE/NASA 100-kW wind turbine generator

    Science.gov (United States)

    Seidel, R. C.; Gold, H.; Wenzel, L. M.

    1978-01-01

    Progress in explaining variations of power experienced in the on-line operation of a 100 kW experimental wind turbine-generator is reported. Data are presented that show the oscillations tend to be characteristic of a wind-driven synchronous generator because of low torsional damping in the power train, resonances of its large structure, and excitation by unsteady and nonuniform wind flow. The report includes dynamic analysis of the drive-train torsion, the generator, passive driveline damping, and active pitch control as well as correlation with experimental recordings. The analysis assumes one machine on an infinite bus with constant generator-field excitation.

  7. Hierarchical parameter estimation of DFIG and drive train system in a wind turbine generator

    Institute of Scientific and Technical Information of China (English)

    Xueping PAN; Ping JU; Feng WU; Yuqing JIN

    2017-01-01

    A new hierarchical parameter estimation method for doubly fed induction generator (DFIG) and drive train system in a wind turbine generator (WTG) is proposed in this paper.Firstly,the parameters of the DFIG and the drive train are estimated locally under different types of disturbances.Secondly,a coordination estimation method is further applied to identify the parameters of the DFIG and the drive train simultaneously with the purpose of attaining the global optimal estimation results.The main benefit of the proposed scheme is the improved estimation accuracy.Estimation results confirm the applicability of the proposed estimation technique.

  8. Autonomous Voltage Security Regions to Prevent Cascading Trip Faults in Wind Turbine Generators

    DEFF Research Database (Denmark)

    Niu, Tao; Guo, Qinglai; Sun, Hongbin

    2016-01-01

    Cascading trip faults in large-scale wind power centralized integration areas bring new challenges to the secure operation of power systems. In order to deal with the complexity of voltage security regions and the computation difficulty, this paper proposes an autonomous voltage security region...... wind farm, an AVSR is determined to guarantee the normal operation of each wind turbine generator (WTG), while in the control center, each region is designed in order to guarantee secure operation both under normal conditions and after an N-1 contingency. A real system in Northern China was used...

  9. Fast Coordinated Control of DFIG Wind Turbine Generators for Low and High Voltage Ride-Through

    DEFF Research Database (Denmark)

    Wang, Yun; Wu, Qiuwei; Xu, Honghua

    2014-01-01

    This paper presents a fast coordinated control scheme of the rotor side converter (RSC), the DC chopper and the grid side converter (GSC) of doubly fed induction generator (DFIG) wind turbine generators (WTGs) which is to improve the low voltage ride through (LVRT) and high voltage ride through...... were proposed considering the characteristics of the DFIG WTGs during voltage changes. The fast coordinated control of RSC and GSC were developed based on the characteristic analysis in order to realize efficient LVRT and HVRT of the DFIG WTGs. The proposed fast coordinated control schemes were...

  10. Stiffness Characteristics of Composite Rotor Blades With Elastic Couplings

    Science.gov (United States)

    Piatak, David J.; Nixon, Mark W.; Kosmatka, John B.

    1997-01-01

    Recent studies on rotor aeroelastic response and stability have shown the beneficial effects of incorporating elastic couplings in composite rotor blades. However, none of these studies have clearly identified elastic coupling limits and the effects of elastic couplings on classical beam stiffnesses of representative rotor blades. Knowledge of these limits and effects would greatly enhance future aeroelastic studies involving composite rotor blades. The present study addresses these voids and provides a preliminary design database for investigators who may wish to study the effects of elastic couplings on representative blade designs. The results of the present study should provide a basis for estimating the potential benefits associated with incorporating elastic couplings without the need for first designing a blade cross section and then performing a cross-section analysis to obtain the required beam section properties as is customary in the usual one-dimensional beam-type approach.

  11. Short term hydroelectric power system scheduling with wind turbine generators using the multi-pass iteration particle swarm optimization approach

    International Nuclear Information System (INIS)

    Lee, T.-Y.

    2008-01-01

    This paper uses multi-pass iteration particle swarm optimization (MIPSO) to solve short term hydroelectric generation scheduling of a power system with wind turbine generators. MIPSO is a new algorithm for solving nonlinear optimal scheduling problems. A new index called iteration best (IB) is incorporated into particle swarm optimization (PSO) to improve solution quality. The concept of multi-pass dynamic programming is applied to modify PSO further and improve computation efficiency. The feasible operational regions of the hydro units and pumped storage plants over the whole scheduling time range must be determined before applying MIPSO to the problem. Wind turbine power generation then shaves the power system load curves. Next, MIPSO calculates hydroelectric generation scheduling. It begins with a coarse time stage and searching space and refines the time interval between two time stages and the search spacing pass by pass (iteration). With the cooperation of agents called particles, the near optimal solution of the scheduling problem can be effectively reached. The effects of wind speed uncertainty were also considered in this paper. The feasibility of the new algorithm is demonstrated by a numerical example, and MIPSO solution quality and computation efficiency are compared to those of other algorithms

  12. Implementation of draft IEC Generic Model of Type 1 Wind Turbine Generator in PowerFactory and Simulink

    DEFF Research Database (Denmark)

    Zhao, Haoran; Wu, Qiuwei; Sørensen, Poul Ejnar

    2013-01-01

    This paper presents the implementation work of IEC generic model of Type 1 wind turbine generator (WTG) in two commercial simulation tools: DIgSILENT PowerFactory (PF) and Matlab Simulink. The model topology, details of the composite blocks and implementation procedure in PF and Simulink environm......This paper presents the implementation work of IEC generic model of Type 1 wind turbine generator (WTG) in two commercial simulation tools: DIgSILENT PowerFactory (PF) and Matlab Simulink. The model topology, details of the composite blocks and implementation procedure in PF and Simulink...

  13. Mod-5A Wind Turbine Generator Program Design Report. Volume 2: Conceptual and Preliminary Design, Book 1

    Science.gov (United States)

    1984-01-01

    The design, development and analysis of the 7.3 MW MOD-5A wind turbine generator is documented. There are four volumes. In Volume 2, book 1 the requirements and criteria for the design are presented. The conceptual design studies, which defined a baseline configuration and determined the weights, costs and sizes of each subsystem, are described. The development and optimization of the wind turbine generator are presented through the description of the ten intermediate configurations between the conceptual and final designs. Analyses of the system's load and dynamics are presented.

  14. Aeroelastic response and stability of tiltrotors with elastically-coupled composite rotor blades. Ph.D. Thesis

    Science.gov (United States)

    Nixon, Mark W.

    1993-01-01

    elastic extension-twist coupling of the rotor blade has the capability of significantly improving tiltrotor aerodynamic performance. This concept, however, is shown to have, in general, a negative impact on stability characteristics.

  15. Analysis, design and elastic tailoring of composite rotor blades

    Science.gov (United States)

    Rehfield, Lawrence W.; Atilgan, Ali R.

    1987-01-01

    The development of structural models for composite rotor blades is summarized. The models are intended for use in design analysis for the purpose of exploring the potential of elastic tailoring. The research was performed at the Center for Rotary Wing Aircraft Technology.

  16. Efficient Beam-Type Structural Modeling of Rotor Blades

    DEFF Research Database (Denmark)

    Couturier, Philippe; Krenk, Steen

    2015-01-01

    The present paper presents two recently developed numerical formulations which enable accurate representation of the static and dynamic behaviour of wind turbine rotor blades using little modeling and computational effort. The first development consists of an intuitive method to extract fully...... by application to a composite section with bend-twist coupling and a real wind turbine blade....

  17. Protection algorithm for a wind turbine generator based on positive- and negative-sequence fault components

    DEFF Research Database (Denmark)

    Zheng, Tai-Ying; Cha, Seung-Tae; Crossley, Peter A.

    2011-01-01

    A protection relay for a wind turbine generator (WTG) based on positive- and negative-sequence fault components is proposed in the paper. The relay uses the magnitude of the positive-sequence component in the fault current to detect a fault on a parallel WTG, connected to the same power collection...... feeder, or a fault on an adjacent feeder; but for these faults, the relay remains stable and inoperative. A fault on the power collection feeder or a fault on the collection bus, both of which require an instantaneous tripping response, are distinguished from an inter-tie fault or a grid fault, which...... in the fault current is used to decide on either instantaneous or delayed operation. The operating performance of the relay is then verified using various fault scenarios modelled using EMTP-RV. The scenarios involve changes in the position and type of fault, and the faulted phases. Results confirm...

  18. Fast Coordinated Control of DFIG Wind Turbine Generators for Low and High Voltage Ride-Through

    Directory of Open Access Journals (Sweden)

    Yun Wang

    2014-06-01

    Full Text Available This paper presents a fast coordinated control scheme of the rotor side converter (RSC, the Direct Current (DC chopper and the grid side converter (GSC of doubly fed induction generator (DFIG wind turbine generators (WTGs to improve the low voltage ride through (LVRT and high voltage ride through (HVRT capability of the DFIG WTGs. The characteristics of DFIG WTGs under voltage sags and swells were studied focusing on the DFIG WTG stator flux and rotor voltages during the transient periods of grid voltage changes. The protection schemes of the rotor crowbar circuit and the DC chopper circuit were proposed considering the characteristics of the DFIG WTGs during voltage changes. The fast coordinated control of RSC and GSC were developed based on the characteristic analysis in order to realize efficient LVRT and HVRT of the DFIG WTGs. The proposed fast coordinated control schemes were verified by time domain simulations using Matlab-Simulink.

  19. Dynamics of a Flywheel Energy Storage System Supporting a Wind Turbine Generator in a Microgrid

    Science.gov (United States)

    Nair S, Gayathri; Senroy, Nilanjan

    2016-02-01

    Integration of an induction machine based flywheel energy storage system with a wind energy conversion system is implemented in this paper. The nonlinear and linearized models of the flywheel are studied, compared and a reduced order model of the same simulated to analyze the influence of the flywheel inertia and control in system response during a wind power change. A quantification of the relation between the inertia of the flywheel and the controller gain is obtained which allows the system to be considered as a reduced order model that is more controllable in nature. A microgrid setup comprising of the flywheel energy storage system, a two mass model of a DFIG based wind turbine generator and a reduced order model of a diesel generator is utilized to analyse the microgrid dynamics accurately in the event of frequency variations arising due to wind power change. The response of the microgrid with and without the flywheel is studied.

  20. Implementation of IEC Generic Model Type 1 Wind Turbine Generators using RTDS

    DEFF Research Database (Denmark)

    Cha, Seung-Tae; Wu, Qiuwei; Zhao, Haoran

    With the ever increasing penetration of the wind power generation, transmission system operators (TSOs) and distribution system operators (DSOs) are demanding an accurate dynamic wind turbine generator (WTG) models for power system stability studies. However, the confidential requirements from wind...... are useful tools to evaluate the impact of the wind power on the power system stability. Thus, a strong stimulus exists for the development of a generic dynamic model in order to further investigate the dynamic response of WTG under grid disturbances. This paper presents the implementation of the IEC generic...... turbine manufacturers prevent the academia and researchers from working on a real or/and manufacturer specific models. A generic WTG model is of great interest that does not contain the confidential information meanwhile represents the manufacturer specific models. These generic dynamic simulation models...

  1. Background and system description of the Mod 1 wind turbine generator

    Science.gov (United States)

    Ernst, E. H.

    1978-01-01

    The Mod-1 wind turbine considered is a large utility-class machine, operating in the high wind regime, which has the potential for generation of utility grade power at costs competitive with other alternative energy sources. A Mod-1 wind turbine generator (WTG) description is presented, taking into account the two variable-pitch steel blades of the rotor, the drive train, power generation/control, the Nacelle structure, and the yaw drive. The major surface elements of the WTG are the ground enclosure, the back-up battery system, the step-up transformer, elements of the data system, cabling, area lighting, and tower foundation. The final system weight (rotor, Nacelle, and tower) is expected to be about 650,000 pounds. The WTG will be capable of delivering 1800 kW to the utility grid in a wind-speed above 25 mph.

  2. The MOD-OA 200 kilowatt wind turbine generator design and analysis report

    Science.gov (United States)

    Andersen, T. S.; Bodenschatz, C. A.; Eggers, A. G.; Hughes, P. S.; Lampe, R. F.; Lipner, M. H.; Schornhorst, J. R.

    1980-01-01

    The project requirements, approach, system description, design requirements, design, analysis, system tests, installation safety considerations, failure modes and effects analysis, data acquisition, and initial performance for the MOD-OA 200 kw wind turbine generator are discussed. The components, the rotor, driven train, nacelle equipment, yaw drive mechanism and brake, tower, foundation, electrical system, and control systems are presented. The rotor includes the blades, hub and pitch change mechanism. The drive train includes the low speed shaft, speed increaser, high speed shaft, and rotor brake. The electrical system includes the generator, switchgear, transformer, and utility connection. The control systems are the blade pitch, yaw, and generator control, and the safety system. Manual, automatic, and remote control and Dynamic loads and fatigue are analyzed.

  3. Computational and experimental optimization of the exhaust air energy recovery wind turbine generator

    International Nuclear Information System (INIS)

    Tabatabaeikia, Seyedsaeed; Ghazali, Nik Nazri Bin Nik; Chong, Wen Tong; Shahizare, Behzad; Izadyar, Nima; Esmaeilzadeh, Alireza; Fazlizan, Ahmad

    2016-01-01

    Highlights: • Studying the viability of harvesting wasted energy by exhaust air recovery generator. • Optimizing the design using response surface methodology. • Validation of optimization and computation result by performing experimental tests. • Investigation of flow behaviour using computational fluid dynamic simulations. • Performing the technical and economic study of the exhaust air recovery generator. - Abstract: This paper studies the optimization of an innovative exhaust air recovery wind turbine generator through computational fluid dynamic (CFD) simulations. The optimization strategy aims to optimize the overall system energy generation and simultaneously guarantee that it does not violate the cooling tower performance in terms of decreasing airflow intake and increasing fan motor power consumption. The wind turbine rotor position, modifying diffuser plates, and introducing separator plates to the design are considered as the variable factors for the optimization. The generated power coefficient is selected as optimization objective. Unlike most of previous optimizations in field of wind turbines, in this study, response surface methodology (RSM) as a method of analytical procedures optimization has been utilised by using multivariate statistic techniques. A comprehensive study on CFD parameters including the mesh resolution, the turbulence model and transient time step values is presented. The system is simulated using SST K-ω turbulence model and then both computational and optimization results are validated by experimental data obtained in laboratory. Results show that the optimization strategy can improve the wind turbine generated power by 48.6% compared to baseline design. Meanwhile, it is able to enhance the fan intake airflow rate and decrease fan motor power consumption. The obtained optimization equations are also validated by both CFD and experimental results and a negligible deviation in range of 6–8.5% is observed.

  4. Implementation of IEC Generic Model of Type 1 Wind Turbine Generator in DIgSILENT PowerFactory

    DEFF Research Database (Denmark)

    Zhao, Haoran; Wu, Qiuwei; Margaris, Ioannis

    2013-01-01

    The implementation method for the International Electrotechnical Commission (IEC) generic models of Type 1 wind turbine generator (WTG) in DIgSILENT PowerFactory is presented. The following items are described, i.e. model structure, model blocks and how to implement these blocks in the PowerFactory...

  5. Mod-5A wind turbine generator program design report. Volume 2: Conceptual and preliminary design, book 2

    Science.gov (United States)

    1984-01-01

    The design, development and analysis of the 7.3 MW MOD-5A wind tunnel generator is documented. There are four volumes. In Volume 2, book 2 the requirements and criteria for the design are presented. The development tests, which determined or characterized many of the materials and components of the wind turbine generator, are described.

  6. Rotor blade boundary layer measurement hardware feasibility demonstration

    Science.gov (United States)

    Clark, D. R.; Lawton, T. D.

    1972-01-01

    A traverse mechanism which allows the measurement of the three dimensional boundary layers on a helicopter rotor blade has been built and tested on a full scale rotor to full scale conditions producing centrifugal accelerations in excess of 400 g and Mach numbers of 0.6 and above. Boundary layer velocity profiles have been measured over a range of rotor speeds and blade collective pitch angles. A pressure scanning switch and transducer were also tested on the full scale rotor and found to be insensitive to centrifugal effects within the normal main rotor operating range. The demonstration of the capability to measure boundary layer behavior on helicopter rotor blades represents the first step toward obtaining, in the rotating system, data of a quality comparable to that already existing for flows in the fixed system.

  7. Preform spar cap for a wind turbine rotor blade

    Science.gov (United States)

    Livingston, Jamie T [Simpsonville, SC; Driver, Howard D [Greer, SC; van Breugel, Sjef [Enschede, NL; Jenkins, Thomas B [Cantonment, FL; Bakhuis, Jan Willem [Nijverdal, NL; Billen, Andrew J [Daarlerveen, NL; Riahi, Amir [Pensacola, FL

    2011-07-12

    A spar cap for a wind turbine rotor blade. The spar cap may include multiple preform components. The multiple preform components may be planar sheets having a swept shape with a first end and a second end. The multiple preform components may be joined by mating the first end of a first preform component to the second end of a next preform component, forming the spar cap.

  8. Design of a wind turbine-generator system considering the conformability to wind velocity fluctuations

    Energy Technology Data Exchange (ETDEWEB)

    Wakui, Tetsuya; Hashizume, Takumi; Outa, Eisuke

    1999-07-01

    The conformability of the rated power output of the wind turbine-generator system and of the wind turbine type to wind velocity fluctuations are investigated with a simulation model. The authors examine three types of wind turbines: the Darrieus-Savonius hybrid, the Darrieus proper and the Propeller. These systems are mainly operated at a constant tip speed ratio, which refers to a maximum power coefficient points. As a computed result of the net extracting power, the Darrieus turbine proper has little conformability to wind velocity fluctuations because of its output characteristics. As for the other turbines, large-scale systems do not always have an advantage over small-scale systems as the effect of its dynamic characteristics. Furthermore, it is confirmed that the net extracting power of the Propeller turbine, under wind direction fluctuation, is much reduced when compared with the hybrid wind turbine. Thus, the authors conclude that the appropriate rated power output of the system exists with relation to the wind turbine type for each wind condition.

  9. Coupling of electromagnetic and structural dynamics for a wind turbine generator

    International Nuclear Information System (INIS)

    Matzke, D; Rick, S; Schelenz, R; Jacobs, G; Hameyer, K; Hollas, S

    2016-01-01

    This contribution presents a model interface of a wind turbine generator to represent the reciprocal effects between the mechanical and the electromagnetic system. Therefore, a multi-body-simulation (MBS) model in Simpack is set up and coupled with a quasi-static electromagnetic (EM) model of the generator in Matlab/Simulink via co-simulation. Due to lack of data regarding the structural properties of the generator the modal properties of the MBS model are fitted with respect to results of an experimental modal analysis (EMA) on the reference generator. The used method and the results of this approach are presented in this paper. The MB S model and the interface are set up in such a way that the EM forces can be applied to the structure and the response of the structure can be fed back to the EM model. The results of this cosimulation clearly show an influence of the feedback of the mechanical response which is mainly damping in the torsional degree of freedom and effects due to eccentricity in radial direction. The accuracy of these results will be validated via test bench measurements and presented in future work. Furthermore it is suggested that the EM model should be adjusted in future works so that transient effects are represented. (paper)

  10. A Comparative Computational Fluid Dynamics Study on an Innovative Exhaust Air Energy Recovery Wind Turbine Generator

    Directory of Open Access Journals (Sweden)

    Seyedsaeed Tabatabaeikia

    2016-05-01

    Full Text Available Recovering energy from exhaust air systems of building cooling towers is an innovative idea. A specific wind turbine generator was designed in order to achieve this goal. This device consists of two Giromill vertical axis wind turbines (VAWT combined with four guide vanes and two diffuser plates. It was clear from previous literatures that no comprehensive flow behavior study had been carried out on this innovative device. Therefore, the working principle of this design was simulated using the Analysis System (ANSYS Fluent computational fluid dynamics (CFD package and the results were compared to experimental ones. It was perceived from the results that by introducing the diffusers and then the guide vanes, the overall power output of the wind turbine was improved by approximately 5% and 34%, respectively, compared to using VAWT alone. In the case of the diffusers, the optimum angle was found to be 7°, while for guide vanes A and B, it was 70° and 60° respectively. These results were in good agreement with experimental results obtained in the previous experimental study. Overall, it can be concluded that exhaust air recovery turbines are a promising form of green technology.

  11. Energy Storage Opportunities and Capabilities in a Type 3 Wind Turbine Generator: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Muljadi, Eduard; Gevorgian, Vahan; Hoke, Andy

    2016-09-01

    Wind power plants and other renewable power plants with power electronic interfaces are capable of delivering frequency response (both governor and/or inertial response) to the grid by a control action; thus, the reduction of available online inertia as conventional power plants are retired can be compensated by designing renewable power plant controls to include frequency response. The source of energy to be delivered as inertial response is determined by the type of generation and control strategy chosen. The cost of energy storage is expected to drop over time, and global research activities on energy storage are very active, funded both by the private industry and governments. Different industry sectors (e.g., transportation, energy) are the major drivers of the recent storage research and development. This work investigates the opportunities and capabilities of deploying energy storage in renewable power plants. In particular, we focus on wind power plants with doubly-fed induction generators, or Type 3 wind turbine generator (WTGs). We find that the total output power of a system with Type 3 WTGs with energy storage can deliver a power boost during inertial response that is up to 45% higher than one without energy storage without affecting the torque limit, thus enabling an effective delivery of ancillary services to the grid.

  12. National Renewable Energy Laboratory program on lightning risk and wind turbine generator protection

    Energy Technology Data Exchange (ETDEWEB)

    Muljadi, E. [National Renewable Energy Lab., Golden, CO (United States); McNiff, B. [McNiff Light Industry, Blue Hill, ME (United States)

    1997-12-31

    In the early development of wind turbine generators (WTG) in the United States, wind farms were primarily located in California where lightning activity is the lowest in the United States. As such, lightning protection for wind turbines was not considered to be a major issue for designers or wind farm operators. However, wind turbine installations are expanding into the Midwest, Southwest and other regions of the United States where lightning activity is significantly more intense and lightning damage to wind turbines is more common. There is a growing need, therefore, to better understand lightning activity on wind farms and to improve wind turbine lightning protection systems. In support of the U.S. Department of Energy/Electric Power Research Institute (DOE/EPRI) Utility Wind Turbine Verification Program (TVP), the National Renewable Energy Laboratory (NREL) has recently begun to take steps to determine the extent of damage due to lightning and the effectiveness of various lightning protection techniques for wind power plants. Working through the TVP program, NREL will also perform outreach and education to (1) help manufacturers to provide equipment that is adequately designed to survive lightning, (2) make sure that operators are aware of effective safety procedures, and (3) help site designers and wind farm developers take the risk of lightning into account as effectively as possible.

  13. Measured effects of wind turbine generation at the Block Island Power Company

    Science.gov (United States)

    Wilreker, V. F.; Smith, R. F.; Stiller, P. H.; Scot, G. W.; Shaltens, R. K.

    1984-01-01

    Data measurements made on the NASA MOD-OA 200-kw wind-turbine generator (WTG) installed on a utility grid form the basis for an overall performance analysis. Fuel displacement/-savings, dynamic interactions, and WTG excitation (reactive-power) control effects are studied. Continuous recording of a large number of electrical and mechanical variables on FM magnetic tape permit evaluation and correlation of phenomena over a bandwidth of at least 20 Hz. Because the wind-power penetration reached peaks of 60 percent, the impact of wind fluctuation and wind-turbine/diesel-utility interaction is evaluated in a worst-case scenario. The speed-governor dynamics of the diesel units exhibited an underdamped response, and the utility operation procedures were not altered to optimize overall WTG/utility performance. Primary findings over the data collection period are: a calculated 6.7-percent reduction in fuel consumption while generating 11 percent of the total electrical energy; acceptable system voltage and frequency fluctuations with WTG connected; and applicability of WTG excitation schemes using voltage, power, or VARS as the controlled variable.

  14. Dynamic Analysis of Jacket Substructure for Offshore Wind Turbine Generators under Extreme Environmental Conditions

    Directory of Open Access Journals (Sweden)

    Wen-Jeng Lai

    2016-10-01

    Full Text Available In order to develop dynamic analysis technologies regarding the design of offshore wind turbine generators (OWTGs, a special project called Offshore Code Comparison Collaboration Continuation (OC4 was conducted by IEA (International Energy Agency in 2010. A similar project named INER-OC4 has been performed by the Institute of Nuclear Energy Research (INER to develop the OWTG technologies of Taiwan. Since the jacket substructure will be applied to Taiwan OWTGs before 2020, the INER-OC4 project has been devoted to the design and analysis of jacket support structure. In this work, the preliminary result of INER-OC4 is presented. A simplified analysis procedure for jacket support structure has been proposed. Both of the NREL (National Renewable Energy Laboratory 5 MW OWTG FAST model and OC4 jacket substructure model have been built and analyzed under severe design load cases (DLCs of IEC (International Electrotechnical commission 61400-3. Simulation results of six severe DLCs are performed in this work and the results are in agreement with the requirements of API (American Petroleum Institute and NORSOK (Norwegian Petroleum Industry standards.

  15. Simulation of Lightning Overvoltage Distribution on Stator Windings of Wind Turbine Generators

    Institute of Scientific and Technical Information of China (English)

    LIU Rong; LIU Xue-zhong; WANG Ying; LI Dan-dan

    2011-01-01

    This paper analyzes lightning surge on the stator windings of wind turbine generators. The path of lightning in the wind turbines was analyzed. An equivalent circuit model for megawatt direct-driven wind turbine system was developed, in which high-frequency distributed parameters of the blade conducts, tower, power cables and stator windings of generator were calculated based on finite element method, and the models of converter, grounding, loads, surge protection devices and power grid were established. The voltage distribution along stator windings, when struck by lightning with 10/350 ~ts wave form and different amplitude current between 50 kA and 200 kA, was simulated u- sing electro-magnetic transient analysis method. The simulated results show that the highest coil-to-core voltage peak appears on the last coil or near the neutral of stator windings, and the voltage distribution along the windings is non- uniform initially. The voltage drops of each coil fall from first to last coil, and the highest voltage drop appears on the first coil. The insulation damage may occur on the windings under lightning overvoltage. The surge arresters can re- strain the lightning surge in effect and protect the insulation. The coil-to-core voltage in the end of windings is nearly 19.5 kV under the 200 kA lightning current without surge arresters on the terminal of generator, but is only 2.7 kV with arresters.

  16. Design of a 3 kW wind turbine generator with thin airfoil blades

    Energy Technology Data Exchange (ETDEWEB)

    Ameku, Kazumasa; Nagai, Baku M.; Roy, Jitendro Nath [Faculty of Mechanical Engineering, University of the Ryukyus, 1 Senbaru, Nishihara-cho, Okinawa 903-0213 (Japan)

    2008-09-15

    Three blades of a 3 kW prototype wind turbine generator were designed with thin airfoil and a tip speed ratio of 3. The wind turbine has been controlled via two control methods: the variable pitch angle and by regulation of the field current of the generator and examined under real wind conditions. The characteristics of the thin airfoil, called ''Seven arcs thin airfoil'' named so because the airfoil is composed of seven circular arcs, are analyzed with the airfoil design and analysis program XFOIL. The thin airfoil blade is designed and calculated by blade element and momentum theory. The performance characteristics of the machine such as rotational speed, generator output as well as stability for wind speed changes are described. In the case of average wind speeds of 10 m/s and a maximum of 19 m/s, the automatically controlled wind turbine ran safely through rough wind conditions and showed an average generator output of 1105 W and a power coefficient 0.14. (author)

  17. A New Wind Turbine Generating System Model for Balanced and Unbalanced Distribution Systems Load Flow Analysis

    Directory of Open Access Journals (Sweden)

    Ahmet Koksoy

    2018-03-01

    Full Text Available Wind turbine generating systems (WTGSs, which are conventionally connected to high voltage transmission networks, have frequently been employed as distributed generation units in today’s distribution networks. In practice, the distribution networks always have unbalanced bus voltages and line currents due to uneven distribution of single or double phase loads over three phases and asymmetry of the lines, etc. Accordingly, in this study, for the load flow analysis of the distribution networks, Conventional Fixed speed Induction Generator (CFIG based WTGS, one of the most widely used WTGS types, is modelled under unbalanced voltage conditions. The Developed model has active and reactive power expressions in terms of induction machine impedance parameters, terminal voltages and input power. The validity of the Developed model is confirmed with the experimental results obtained in a test system. The results of the slip calculation based phase-domain model (SCP Model, which was previously proposed in the literature for CFIG based WTGSs under unbalanced voltages, are also given for the comparison. Finally, the Developed model and the SCP model are implemented in the load flow analysis of the IEEE 34 bus test system with the CFIG based WTGSs and unbalanced loads. Thus, it is clearly pointed out that the results of the load flow analysis implemented with both models are very close to each other, and the Developed model is computationally more efficient than the SCP model.

  18. MOD-0A 200 kW wind turbine generator design and analysis report

    Science.gov (United States)

    Anderson, T. S.; Bodenschatz, C. A.; Eggers, A. G.; Hughes, P. S.; Lampe, R. F.; Lipner, M. H.; Schornhorst, J. R.

    1980-01-01

    The design, analysis, and initial performance of the MOD-OA 200 kW wind turbine generator at Clayton, NM is documented. The MOD-OA was designed and built to obtain operation and performance data and experience in utility environments. The project requirements, approach, system description, design requirements, design, analysis, system tests, installation, safety considerations, failure modes and effects analysis, data acquisition, and initial performance for the wind turbine are discussed. The design and analysis of the rotor, drive train, nacelle equipment, yaw drive mechanism and brake, tower, foundation, electricl system, and control systems are presented. The rotor includes the blades, hub, and pitch change mechanism. The drive train includes the low speed shaft, speed increaser, high speed shaft, and rotor brake. The electrical system includes the generator, switchgear, transformer, and utility connection. The control systems are the blade pitch, yaw, and generator control, and the safety system. Manual, automatic, and remote control are discussed. Systems analyses on dynamic loads and fatigue are presented.

  19. MOD-5A wind turbine generator program design report: Volume 1: Executive Summary

    Science.gov (United States)

    1984-01-01

    The design, development and analysis of the 7.3 MW MOD-5A wind turbine generator covering work performed between July 1980 and June 1984 is discussed. The report is divided into four volumes: Volume 1 summarizes the entire MOD-5A program, Volume 2 discusses the conceptual and preliminary design phases, Volume 3 describes the final design of the MOD-5A, and Volume 4 contains the drawings and specifications developed for the final design. Volume 1, the Executive Summary, summarizes all phases of the MOD-5A program. The performance and cost of energy generated by the MOD-5A are presented. Each subsystem - the rotor, drivetrain, nacelle, tower and foundation, power generation, and control and instrumentation subsystems - is described briefly. The early phases of the MOD-5A program, during which the design was analyzed and optimized, and new technologies and materials were developed, are discussed. Manufacturing, quality assurance, and safety plans are presented. The volume concludes with an index of volumes 2 and 3.

  20. Integral Twist Actuation of Helicopter Rotor Blades for Vibration Reduction

    Science.gov (United States)

    Shin, SangJoon; Cesnik, Carlos E. S.

    2001-01-01

    Active integral twist control for vibration reduction of helicopter rotors during forward flight is investigated. The twist deformation is obtained using embedded anisotropic piezocomposite actuators. An analytical framework is developed to examine integrally-twisted blades and their aeroelastic response during different flight conditions: frequency domain analysis for hover, and time domain analysis for forward flight. Both stem from the same three-dimensional electroelastic beam formulation with geometrical-exactness, and axe coupled with a finite-state dynamic inflow aerodynamics model. A prototype Active Twist Rotor blade was designed with this framework using Active Fiber Composites as the actuator. The ATR prototype blade was successfully tested under non-rotating conditions. Hover testing was conducted to evaluate structural integrity and dynamic response. In both conditions, a very good correlation was obtained against the analysis. Finally, a four-bladed ATR system is built and tested to demonstrate its concept in forward flight. This experiment was conducted at NASA Langley Tansonic Dynamics Tunnel and represents the first-of-a-kind Mach-scaled fully-active-twist rotor system to undergo forward flight test. In parallel, the impact upon the fixed- and rotating-system loads is estimated by the analysis. While discrepancies are found in the amplitude of the loads under actuation, the predicted trend of load variation with respect to its control phase correlates well. It was also shown, both experimentally and numerically, that the ATR blade design has the potential for hub vibratory load reduction of up to 90% using individual blade control actuation. Using the numerical framework, system identification is performed to estimate the harmonic transfer functions. The linear time-periodic system can be represented by a linear time-invariant system under the three modes of blade actuation: collective, longitudinal cyclic, and lateral cyclic. A vibration

  1. Active Power and Flux Control of a Self-Excited Induction Generator for a Variable-Speed Wind Turbine Generation

    Energy Technology Data Exchange (ETDEWEB)

    Na, Woonki; Muljadi, Eduard; Leighty, Bill; Kim, Jonghoon

    2017-05-11

    A Self-Excited Induction Generation (SEIG) for a variable speed wind turbine generation(VS-WG) is normally considered to be a good candidate for implementation in stand-alone applications such as battery charging, hydrogenation, water pumping, water purification, water desalination, and etc. In this study, we have examined a study on active power and flux control strategies for a SEIG for a variable speed wind turbine generation. The control analysis for the proposed system is carried out by using PSCAD software. In the process, we can optimize the control design of the system, thereby enhancing and expediting the control design procedure for this application. With this study, this control design for a SEIG for VS-WG can become the industry standard for analysis and development in terms of SEIG.

  2. Effect of operating methods of wind turbine generator system on net power extraction under wind velocity fluctuations in fields

    Energy Technology Data Exchange (ETDEWEB)

    Wakui, Tetsuya; Yamaguchi, Kazuya; Hashizume, Takumi [Waseda Univ., Advanced Research Inst. for Science and Engineering, Tokyo (Japan); Outa, Eisuke [Waseda Univ., Mechanical Engineering Dept., Tokyo (Japan); Tanzawa, Yoshiaki [Nippon Inst. of Technology, Mechanical Engineering Dept., Saitama (Japan)

    1999-01-01

    The effect of how a wind turbine generator system is operated is discussed from the viewpoint of net power extraction with wind velocity fluctuation in relation to the scale and the dynamic behaviour of the system. On a wind turbine generator system consisting of a Darrieus-Savonius hybrid wind turbine, a load generator and a battery, we took up two operating methods: constant tip speed ratio operation for a stand-alone system (Scheme 1) and synchronous operation by connecting a grid (Scheme 2). With our simulation model, using the result of the net extracting power, we clarified that Scheme 1 is more effective than Scheme 2 for small-scale systems. Furthermore, in Scheme 1, the appropriate rated power output of the system under each wind condition can be confirmed. (Author)

  3. Mod-5A wind turbine generator program design report. Volume 3: Final design and system description, book 2

    Science.gov (United States)

    1984-01-01

    The design, development and analysis of the 7.3MW MOD-5A wind turbine generator is documented. The report is divided into four volumes: Volume 1 summarizes the entire MOD-5A program, Volume 2 discusses the conceptual and preliminary design phases, Volume 3 describes the final design of the MOD-5A, and Volume 4 contains the drawings and specifications developed for the final design. Volume 3, book 2 describes the performance and characteristics of the MOD-5A wind turbine generator in its final configuration. The subsystem for power generation, control, and instrumentation subsystems is described in detail. The manufacturing and construction plans, and the preparation of a potential site on Oahu, Hawaii, are documented. The quality assurance and safety plan, and analyses of failure modes and effects, and reliability, availability and maintainability are presented.

  4. Measurement and Modelling of Multicopter UAS Rotor Blades in Hover

    Science.gov (United States)

    Nowicki, Nathalie

    2016-01-01

    Multicopters are becoming one of the more common and popular type of unmanned aircraft systems (UAS) which have both civilian and military applications. One example being the concept of drone deliveries proposed by the distribution company Amazon [1]. The electrical propulsion is considered to have both faster and easier deliveries and also environmental benefits compared to other vehicles that still use fossil fuel. Other examples include surveillance and just simple entertainment. The reason behind their success is often said to be due to their small size, relatively low cost, simple structure and finally simple usage. With an increase in the UAS market comes challenges in terms of security, as both people and other aircrafts could be harmed if not used correctly. Therefore further studies and regulations are needed to ensure that future use of drones, especially in the civilian and public sectors, are safe and efficient. Thorough research has been done on full scale, man or cargo transporting, helicopters so that most parts of flight and performance are fairly well understood. Yet not much of it have been verified for small multicopters. Until today many studies and research projects have been done on the control systems, navigation and aerodynamics of multicopters. Many of the methods used today for building multicopters involve a process of trial an error of what will work well together, and once that is accomplished some structural analysis of the multicopter bodies might be done to verify that the product will be strong enough and have a decent aerodynamic performance. However, not much has been done on the research of the rotor blades, especially in terms of structural stress analyses and ways to ensure that the commonly used parts are indeed safe and follow safety measures. Some producers claim that their propellers indeed have been tested, but again that usually tends towards simple fluid dynamic analyses and even simpler stress analyses. There is no real

  5. 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 ...

  6. Wind Turbine Generator System Acoustic Noise Test Report for the Gaia Wind 11-kW Wind Turbine

    Energy Technology Data Exchange (ETDEWEB)

    Huskey, A.

    2011-11-01

    This report details the acoustic noise test conducted on the Gaia-Wind 11-kW wind turbine at the National Wind Technology Center. The test turbine is a two- bladed, downwind wind turbine with a rated power of 11 kW. The test turbine was tested in accordance with the International Electrotechnical Commission standard, IEC 61400-11 Ed 2.1 2006-11 Wind Turbine Generator Systems -- Part 11 Acoustic Noise Measurement Techniques.

  7. Generic Models of Wind Turbine Generators for Advanced Applications in a VSC-based Offshore HVDC Network

    DEFF Research Database (Denmark)

    Zeni, Lorenzo; Margaris, Ioannis; Hansen, Anca Daniela

    This paper focuses on generic Type 4 wind turbine generators models, their applicability in modern HVDC connections and their capability to provide advanced ancillary services therefrom. A point-to-point HVDC offshore connection is considered. Issues concerning coordinated HVDC and wind farm...... involving the HVDC converters- The performance against frequency disturbances of the two presented configurations is assessed and discussed by means of simulations....

  8. WTG Energy Systems' MP1-200 200 kilowatt wind turbine generator. [a fixed pitch rotor configuration driving a synchronous generator

    Science.gov (United States)

    Spaulding, A. P., Jr.

    1979-01-01

    The preliminary design criteria of the MP1-200 wind turbine are given along with a brief description of the wind turbine generator. Performance and operational experience and cost factors are included. Recommendations for additional research are listed.

  9. Understanding Dynamic Model Validation of a Wind Turbine Generator and a Wind Power Plant: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Muljadi, Eduard; Zhang, Ying Chen; Gevorgian, Vahan; Kosterev, Dmitry

    2016-09-01

    Regional reliability organizations require power plants to validate the dynamic models that represent them to ensure that power systems studies are performed to the best representation of the components installed. In the process of validating a wind power plant (WPP), one must be cognizant of the parameter settings of the wind turbine generators (WTGs) and the operational settings of the WPP. Validating the dynamic model of a WPP is required to be performed periodically. This is because the control parameters of the WTGs and the other supporting components within a WPP may be modified to comply with new grid codes or upgrades to the WTG controller with new capabilities developed by the turbine manufacturers or requested by the plant owners or operators. The diversity within a WPP affects the way we represent it in a model. Diversity within a WPP may be found in the way the WTGs are controlled, the wind resource, the layout of the WPP (electrical diversity), and the type of WTGs used. Each group of WTGs constitutes a significant portion of the output power of the WPP, and their unique and salient behaviors should be represented individually. The objective of this paper is to illustrate the process of dynamic model validations of WTGs and WPPs, the available data recorded that must be screened before it is used for the dynamic validations, and the assumptions made in the dynamic models of the WTG and WPP that must be understood. Without understanding the correct process, the validations may lead to the wrong representations of the WTG and WPP modeled.

  10. Preliminary Aerodynamic Investigation of Fan Rotor Blade Morphing

    Science.gov (United States)

    Tweedt, Daniel L.

    2012-01-01

    Various new technologies currently under development may enable controlled blade shape variability, or so-called blade morphing, to be practically employed in aircraft engine fans and compressors in the foreseeable future. The current study is a relatively brief, preliminary computational fluid dynamics investigation aimed at partially demonstrating and quantifying the aerodynamic potential of fan rotor blade morphing. The investigation is intended to provide information useful for near-term planning, as well as aerodynamic solution data sets that can be subsequently analyzed using advanced acoustic diagnostic tools, for the purpose of making fan noise comparisons. Two existing fan system models serve as baselines for the investigation: the Advanced Ducted Propulsor fan with a design tip speed of 806 ft/sec and a pressure ratio of 1.294, and the Source Diagnostic Test fan with a design tip speed of 1215 ft/sec and a pressure ratio of 1.470. Both are 22-in. sub-scale, low-noise research fan/nacelle models that have undergone extensive experimental testing in the 9- by 15-foot Low Speed Wind Tunnel at the NASA Glenn Research Center. The study, restricted to fan rotor blade morphing only, involves a fairly simple blade morphing technique. Specifically, spanwise-linear variations in rotor blade-section setting angle are applied to alter the blade shape; that is, the blade is linearly retwisted from hub to tip. Aerodynamic performance comparisons are made between morphed-blade and corresponding baseline configurations on the basis of equal fan system thrust, where rotor rotational speed for the morphed-blade fan is varied to change the thrust level for that configuration. The results of the investigation confirm that rotor blade morphing could be a useful technology, with the potential to enable significant improvements in fan aerodynamic performance. Even though the study is very limited in scope and confined to simple geometric perturbations of two existing fan

  11. Literature Review on Reasons and Countermeasures on Large-scale Off-grid of Wind Turbine Generator System

    Directory of Open Access Journals (Sweden)

    Zhu Jun

    2015-01-01

    Full Text Available This paper reviews the present situation of the application of wind turbines generator system(WTGS at home and abroad, describes the strategic significance and the value of sustainable development of the wind power in the country, illustrates the problems, a variety of reasons and responses on large-scale off-grid of WTGS, compares the advantages and disadvantages of various methods, gives full consideration to the actual demand for WTGS works and characteristics and points out the further research.

  12. Implementation of IEC Generic Models of Type 1 Wind Turbine Generator in DIgSILENT PowerFactory

    Institute of Scientific and Technical Information of China (English)

    Haoran ZHAO; Qiuwei WU; Ioannis MARGARIS; Poul S(O)RENSEN

    2013-01-01

    The implementation method for the International Electrotechnical Commission (IEC) generic models of Type 1 wind turbine generator (WTG) in DIgSILENT PowerFactory is presented.The following items are described,i.e.model structure,model blocks and how to implement these blocks in the PowerFactory environment.Case studies under both normal and fault conditions are done with the implemented IEC generic models of Type 1 WTG,and dynamic responses are captured and analyzed.The case study results show that the IEC generic models of Type 1 WTG can correctly represent the performances of Type 1 WTG under both normal and fault conditions.

  13. A probability evaluation method of early deterioration condition for the critical components of wind turbine generator systems

    DEFF Research Database (Denmark)

    Hu, Y.; Li, H.; Liao, X

    2016-01-01

    method of early deterioration condition for critical components based only on temperature characteristic parameters. First, the dynamic threshold of deterioration degree function was proposed by analyzing the operational data between temperature and rotor speed. Second, a probability evaluation method...... of early deterioration condition was presented. Finally, two cases showed the validity of the proposed probability evaluation method in detecting early deterioration condition and in tracking their further deterioration for the critical components.......This study determines the early deterioration condition of critical components for a wind turbine generator system (WTGS). Due to the uncertainty nature of the fluctuation and intermittence of wind, early deterioration condition evaluation poses a challenge to the traditional vibration...

  14. Determination of the angle of attack on rotor blades

    DEFF Research Database (Denmark)

    Shen, Wen Zhong; Hansen, Martin Otto Laver; Sørensen, Jens Nørkær

    2009-01-01

    Two simple methods for determining the angle of attack (AOA) on a section of a rotor blade are proposed. Both techniques consist of employing the Biot-Savart integral to determine the influence of the bound vorticity on the velocity field. In the first technique, the force distribution along...... the blade and the velocity at a monitor point in the vicinity of the blade are assumed to be known from experiments or CFD computations. The AOA is determined by subtracting the velocity induced by the bound circulation, determined from the loading, from the velocity at the monitor point. In the second...... to be located closer to the blade, and thus to determine the AOA with higher accuracy. Data from CFD computations for flows past the Tellus 95 kW wind turbine at different wind speeds are used to test both techniques. Comparisons show that the proposed methods are in good agreement with existing techniques...

  15. Nonlinear Characteristics of Helicopter Rotor Blade Airfoils: An Analytical Evaluation

    Directory of Open Access Journals (Sweden)

    Constantin Rotaru

    2013-01-01

    Full Text Available Some results are presented about the study of airloads of the helicopter rotor blades, the aerodynamic characteristics of airfoil sections, the physical features, and the techniques for modeling the unsteady effects found on airfoil operating under nominally attached flow conditions away from stall. The unsteady problem was approached on the basis of Theodorsen's theory, where the aerodynamic response (lift and pitching moment is considered as a sum of noncirculatory and circulatory parts. The noncirculatory or apparent mass accounts for the pressure forces required to accelerate the fluid in the vicinity of the airfoil. The apparent mass contributions to the forces and pitching moments, which are proportional to the instantaneous motion, are included as part of the quasi-steady result.

  16. System for manufacturing wooden rotor blades for small wind mills

    Energy Technology Data Exchange (ETDEWEB)

    Moeller, B

    1991-05-01

    Acknowledging the need (also in developing countries) for small windmill wings with various patterns and aerodynamic characteristics a simple, low-cost hand-controlled copying milling machine was built (with standard parts) to reduce production time for one wing to 1-2 hours. A sensor-roll transfers the airfoil pattern to a set of two saw blades, driven by an electric motor, which carves the airfoil out of a wooden beam. It is thus possible to cut out each cross section of the wing and manufacture a constantly reproducible rotor blade. The hard-foam airfoil models - their shapes, material and production, the laminated beam - the preparation of the wood and the lamination, and the copying milling machine itself - its design and how to build, operate and maintain it, are described in detail. (AB)

  17. Optimization model for rotor blades of horizontal axis wind turbines

    Institute of Scientific and Technical Information of China (English)

    LIU Xiong; CHEN Yan; YE Zhiquan

    2007-01-01

    This paper presents an optimization model for rotor blades of horizontal axis wind turbines. The model refers to the wind speed distribution function on the specific wind site, with an objective to satisfy the maximum annual energy output. To speed up the search process and guarantee a global optimal result, the extended compact genetic algorithm (ECGA) is used to carry out the search process.Compared with the simple genetic algorithm, ECGA runs much faster and can get more accurate results with a much smaller population size and fewer function evaluations. Using the developed optimization program, blades of a 1.3 MW stall-regulated wind turbine are designed. Compared with the existing blades, the designed blades have obviously better aerodynamic performance.

  18. Nondestructive evaluation of helicopter rotor blades using guided Lamb modes.

    Science.gov (United States)

    Chakrapani, Sunil Kishore; Barnard, Daniel; Dayal, Vinay

    2014-03-01

    This paper presents an application for turning and direct modes in a complex composite laminate structure. The propagation and interaction of turning modes and fundamental Lamb modes are investigated in the skin, spar and web sections of a helicopter rotor blade. Finite element models were used to understand the various mode conversions at geometric discontinuities such as web-spar joints. Experimental investigation was carried out with the help of air coupled ultrasonic transducers. The turning and direct modes were confirmed with the help of particle displacements and velocities. Experimental B-Scans were performed on damaged and undamaged samples for qualitative and quantitative assessment of the structure. A strong correlation between the numerical and experimental results was observed and reported. Copyright © 2013 Elsevier B.V. All rights reserved.

  19. Aeroelastic behavior of composite rotor blades with swept tips

    Science.gov (United States)

    Yuan, Kuo-An; Friedmann, Peretz P.; Venkatesan, Comandur

    1992-01-01

    This paper presents an analytical study of the aeroelastic behavior of composite rotor blades with straight and swept tips. The blade is modeled by beam type finite elements. A single finite element is used to model the swept tip. The nonlinear equations of motion for the finite element model are derived using Hamilton's principle and based on a moderate deflection theory and accounts for: arbitrary cross-sectional shape, pretwist, generally anisotropic material behavior, transverse shears and out-of-plane warping. Numerical results illustrating the effects of tip sweep, anhedral and composite ply orientation on blade aeroelastic behavior are presented. It is shown that composite ply orientation has a substantial effect on blade stability. At low thrust conditions, certain ply orientations can cause instability in the lag mode. The flap-torsion coupling associated with tip sweep can also induce aeroelastic instability in the blade. This instability can be removed by appropriate ply orientation in the composite construction.

  20. Rotor-blade wheel solves the sediment problems; Loepehjul loeser sedimentproblemer

    Energy Technology Data Exchange (ETDEWEB)

    Bakken, Marte

    2009-07-01

    Test period in Peru is over for the recently developed rotor-blade wheel from the Norwegian firm DynaVec. The result shows that the wear and tear problems caused by sediments in great extent is solved. (AG)

  1. Application of a system modification technique to dynamic tuning of a spinning rotor blade

    Science.gov (United States)

    Spain, C. V.

    1987-01-01

    An important consideration in the development of modern helicopters is the vibratory response of the main rotor blade. One way to minimize vibration levels is to ensure that natural frequencies of the spinning main rotor blade are well removed from integer multiples of the rotor speed. A technique for dynamically tuning a finite-element model of a rotor blade to accomplish that end is demonstrated. A brief overview is given of the general purpose finite element system known as Engineering Analysis Language (EAL) which was used in this work. A description of the EAL System Modification (SM) processor is then given along with an explanation of special algorithms developed to be used in conjunction with SM. Finally, this technique is demonstrated by dynamically tuning a model of an advanced composite rotor blade.

  2. An Experimental Analysis of the Effect of Icing on Wind Turbine Rotor Blades

    DEFF Research Database (Denmark)

    Raja, Muhammad Imran; Hussain, Dil muhammed Akbar; Soltani, Mohsen

    2016-01-01

    Wind Turbine is highly nonlinear plant whose dynamics changes with change in aerodynamics of the rotor blade. Power extracted from the wind turbine is a function of coefficient of power (Cp). Wind turbine installed in the cold climate areas has an icing on its rotor blade which might change its...... aerodynamics. This paper is an experimental investigation of the aerodynamic changes occur due to effect of ice accumulated on the rotor blades of wind turbine. We have tested three small scale model of the NREL's 5MW rotor blade with same profile but simulated different icing effect on them. These models...... are printed with 3D printer and tested one by one in a Wind Tunnel. Lift, drag and moment coefficients are calculated from the measured experimental data and program WT-Perf based on blade-element momentum (BEM) theory is used to predict the performance of wind turbine. Cp curves generated from the test...

  3. Turbine engine rotor blade fault diagnostics through casing pressure and vibration sensors

    International Nuclear Information System (INIS)

    Cox, J; Anusonti-Inthra, P

    2014-01-01

    In this study, an exact solution is provided for a previously indeterminate equation used for rotor blade fault diagnostics. The method estimates rotor blade natural frequency through turbine engine casing pressure and vibration sensors. The equation requires accurate measurements of low-amplitude sideband signals in the frequency domain. With this in mind, statistical evaluation was also completed with the goal of determining the effect of sampling time and frequency on sideband resolution in the frequency domain

  4. Design of helicopter rotor blades with actuators made of a piezomacrofiber composite

    Science.gov (United States)

    Glukhikh, S.; Barkanov, E.; Kovalev, A.; Masarati, P.; Morandini, M.; Riemenschneider, J.; Wierach, P.

    2008-01-01

    For reducing the vibration and noise of helicopter rotor blades, the method of their controlled twisting by using built-in deformation actuators is employed. In this paper, the influence of various design parameters of the blades, including the location of actuators made of a piezomacrofiber material, on the twist angle is evaluated. The results of a parametric analysis performed allowed us to refine the statement of an optimization problem for the rotor blades.

  5. Design, fabrication, and test of a composite material wind turbine rotor blade

    Science.gov (United States)

    Griffee, D. G., Jr.; Gustafson, R. E.; More, E. R.

    1977-01-01

    The aerodynamic design, structural design, fabrication, and structural testing is described for a 60 foot long filament wound, fiberglass/epoxy resin matrix wind turbine rotor blade for a 125 foot diameter, 100 kW wind energy conversion system. One blade was fabricated which met all aerodynamic shape requirements and was structurally capable of operating under all specified design conditions. The feasibility of filament winding large rotor blades was demonstrated.

  6. Design & Evaluation of a Protection Algorithm for a Wind Turbine Generator based on the fault-generated Symmetrical Components

    DEFF Research Database (Denmark)

    Zheng, T. Y.; Cha, Seung-Tae; Lee, B. E.

    2011-01-01

    A protection relay for a wind turbine generator (WTG) based on the fault-generated symmetrical components is proposed in the paper. At stage 1, the relay uses the magnitude of the positive-sequence component in the fault current to distinguish faults on a parallel WTG, connected to the same feeder......, or on an adjacent feeder from those on the connected feeder, on the collection bus, at an inter-tie or at a grid. For the former faults, the relay should remain stable and inoperative whilst the instantaneous or delayed tripping is required for the latter faults. At stage 2, the fault type is first evaluated using...... the relationships of the fault-generated symmetrical components. Then, the magnitude of the positive-sequence component in the fault current is used again to decide on either instantaneous or delayed operation. The operating performance of the relay is then verified using various fault scenarios modelled using...

  7. An improved efficiency of fuzzy sliding mode control of permanent magnet synchronous motor for wind turbine generator pumping system

    International Nuclear Information System (INIS)

    Benchabane, F.; Titaouine, A.; Guettaf, A.; Yahia, K.; Taibi, D.; Bennis, O.

    2012-01-01

    This paper presents an analysis by which the dynamic performances of a permanent magnet synchronous motor (PMSM) motor is controlled through a hysteresis current loop and an outer speed loop with different controllers. The dynamics of the wind turbine pumping drive system with (PI) and a fuzzy sliding mode (FSM) speed controllers are presented. In order to optimize the overall system efficiency, a maximum power point tracker is also used. Simulation is carried out by formatting the mathematical model for wind turbine generator, motor and pump load. The results for such complicated and nonlinear system, with fuzzy sliding mode speed controller show improvement in transient response of the PMSM drive over conventional PI. The effectiveness of the FSM controller is also demonstrated. (author)

  8. A Full-size High Temperature Superconducting Coil Employed in a Wind Turbine Generator Set-up

    DEFF Research Database (Denmark)

    Song, Xiaowei (Andy); Mijatovic, Nenad; Kellers, Jürgen

    2016-01-01

    A full-size stationary experimental set-up, which is a pole pair segment of a 2 MW high temperature superconducting (HTS) wind turbine generator, has been built and tested under the HTS-GEN project in Denmark. The performance of the HTS coil is crucial to the set-up, and further to the development...... is tested in LN2 first, and then tested in the set-up so that the magnetic environment in a real generator is reflected. The experimental results are reported, followed by a finite element simulation and a discussion on the deviation of the results. The tested and estimated Ic in LN2 are 148 A and 143 A...

  9. Ice accretion modeling for wind turbine rotor blades

    Energy Technology Data Exchange (ETDEWEB)

    Chocron, D.; Brahimi, T.; Paraschivoiu, I.; Bombardier, J.A. [Ecole Polytechnique de Montreal (Canada)

    1997-12-31

    The increasing application of wind energy in northern climates implies operation of wind turbines under severe atmospheric icing conditions. Such conditions are well known in the Scandinavian countries, Canada and most of Eastern European countries. An extensive study to develop a procedure for the prediction of ice accretion on wind turbines rotor blades appears to be essential for the safe and economic operation of wind turbines in these cold regions. The objective of the present paper is to develop a computer code capable of simulating the shape and amount of ice which may accumulate on horizontal axis wind turbine blades when operating in icing conditions. The resulting code is capable to predict and simulate the formation of ice in rime and glaze conditions, calculate the flow field and particle trajectories and to perform thermodynamic analysis. It also gives the possibility of studying the effect of different parameters that influence ice formation such as temperature, liquid water content, droplet diameter and accretion time. The analysis has been conducted on different typical airfoils as well as on NASA/DOE Mod-0 wind turbine. Results showed that ice accretion on wind turbines may reduce the power output by more than 20%.

  10. Active twist of model rotor blades with D-spar design

    Directory of Open Access Journals (Sweden)

    A. Kovalovs

    2007-03-01

    Full Text Available The design methodology based on the planning of experiments and response surface technique has been developed for an optimum placement of Macro Fiber Composite (MFC actuators in the helicopter rotor blades. The baseline helicopter rotor blade consists of D-spar made of UD GFRP, skin made of +45o/–45o GFRP, foam core, MFC actuators placement on the skin and balance weight. 3D finite element model of the rotor blade has been built by ANSYS, where the rotor blade skin and spar “moustaches” are modeled by the linear layered structural shell elements SHELL99, and the spar and foam - by 3D 20-node structural solid elements SOLID186. The thermal analyses of 3D finite element model have been developed to investigate an active twist of the helicopter rotor blade. Strain analogy between piezoelectric strains and thermally induced strains is used to model piezoelectric effects. The optimisation results have been obtained for design solutions, connected with the application of active materials, and checked by the finite element calculations.

  11. 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

  12. A multi-frequency fatigue testing method for wind turbine rotor blades

    DEFF Research Database (Denmark)

    Eder, Martin Alexander; Belloni, Federico; Tesauro, Angelo

    2017-01-01

    Rotor blades are among the most delicate components of modern wind turbines. Reliability is a crucial aspect, since blades shall ideally remain free of failure under ultra-high cycle loading conditions throughout their designated lifetime of 20–25 years. Full-scale blade tests are the most accurate...... means to experimentally simulate damage evolution under operating conditions, and are therefore used to demonstrate that a blade type fulfils the reliability requirements to an acceptable degree of confidence. The state-of-the-art testing method for rotor blades in industry is based on resonance...... higher modes contribute more significantly due to their higher cycle count. A numerical feasibility study based on a publicly available large utility rotor blade is used to demonstrate the ability of the proposed approach to outperform the state-of-the-art testing method without compromising fatigue test...

  13. Modeling and Design of a Full-Scale Rotor Blade with Embedded Piezocomposite Actuators

    Science.gov (United States)

    Kovalovs, A.; Barkanov, E.; Ruchevskis, S.; Wesolowski, M.

    2017-05-01

    An optimization methodology for the design of a full-scale rotor blade with an active twist in order to enhance its ability to reduce vibrations and noise is presented. It is based on a 3D finite-element model, the planning of experiments, and the response surface technique to obtain high piezoelectric actuation forces and displacements with a minimum actuator weight and energy applied. To investigate an active twist of the helicopter rotor blade, a structural static analysis using a 3D finite-element model was carried out. Optimum results were obtained at two possible applications of macrofiber composite actuators. The torsion angle found from the finite-element simulation of helicopter rotor blades was successfully validated by its experimental values, which confirmed the modeling accuracy.

  14. Benefit Evaluation of Wind Turbine Generators in Wind Farms Using Capacity-Factor Analysis and Economic-Cost Methods

    DEFF Research Database (Denmark)

    Chen, Zhe; Wang, L.; Yeh, T-H.

    2009-01-01

    Due to the recent price spike of the international oil and the concern of global warming, the development and deployment of renewable energy become one of the most important energy policies around the globe. Currently, there are different capacities and hub heights for commercial wind turbine gen...... height for WTGs that have been installed in Taiwan. Important outcomes affecting wind cost of energy in comparison with economic results using the proposed economic-analysis methods for different WFs are also presented.......Due to the recent price spike of the international oil and the concern of global warming, the development and deployment of renewable energy become one of the most important energy policies around the globe. Currently, there are different capacities and hub heights for commercial wind turbine...... generators (WTGs). To fully capture wind energy, different wind farms (WFs) should select adequate capacity of WTGs to effectively harvest wind energy and maximize their economic benefit. To establish selection criterion, this paper first derives the equations for capacity factor (CF) and pairing performance...

  15. Serially-Connected Compensator for Eliminating the Unbalanced Three-Phase Voltage Impact on Wind Turbine Generators: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Z.; Hsu, P.; Muljadi, E.; Gao, W.

    2015-04-06

    Untransposed transmission lines, unbalanced tap changer operations, and unbalanced loading in weak distribution lines can cause unbalanced-voltage conditions. The resulting unbalanced voltage at the point of interconnection affects proper gird integration and reduces the lifetime of wind turbines due to power oscillations, torque pulsations, mechanical stresses, energy losses, and uneven and overheating of the generator stator winding. This work investigates the dynamic impact of unbalanced voltage on the mechanical and electrical components of integrated Fatigue, Aerodynamics, Structures, and Turbulence (FAST) wind turbine generation systems (WTGs) of Type 1 (squirrel-cage induction generator) and Type 3 (doubly-fed induction generator). To alleviate this impact, a serially-connected compensator for a three-phase power line is proposed to balance the wind turbine-side voltage. Dynamic simulation studies are conducted in MATLAB/Simulink to compare the responses of these two types of wind turbine models under normal and unbalanced-voltage operation conditions and demonstrate the effectiveness of the proposed compensator.

  16. Kurokawa 150-kW wind turbine generator demonstration; 150 kW Kurokawa furyoku hatsudensho ni tsuite

    Energy Technology Data Exchange (ETDEWEB)

    Okamoto, M; Shinohara, M; Sugiyama, T [Kansai Electric Power Co. Inc., Osaka (Japan)

    1996-10-27

    This paper presents the 150kW wind turbine generator erected at a site near Kurokawa dam lake of Kansai Electric Power Co. in Hyogo prefecture. This generator is composed of a horizontal-axis propeller with 3 blades of 27m in diameter and 36/27rpm, and a tower of 30m high. Harmony with the environment was also considered because of the site in a natural park area. Its demonstration test started in Oct. 1996 at annual mean wind velocity of 2m/s. Soft start was realized by controlling inrush current and preventing voltage drop in system interconnection by use of a thyristor circuit. The dual operation system was adopted of a 30kW small generator at lower wind velocity and a 150kW large one at higher velocity. Two kinds of brakes are used, and rotor revolution was reduced by air brake (blade tip spoiler). Mechanical disk brake works for the stopped rotor or emergency stopping. Even if the wind turbine was stopped by exterior factor, if no anomaly of the turbine is found, it automatically re-starts after removal of the factor. The generator is controlled from a remote control station 150km apart through NTT communication line. 6 figs., 2 tabs.

  17. Control system design for the MOD-5A 7.3 mW wind turbine generator

    Science.gov (United States)

    Barton, Robert S.; Hosp, Theodore J.; Schanzenbach, George P.

    1995-01-01

    This paper provides descriptions of the requirements analysis, hardware development and software development phases of the Control System design for the MOD-5A 7.3 mW Wind Turbine Generator. The system, designed by General Electric Company, Advanced Energy Programs Department, under contract DEN 3-153 with NASA Lewis Research Center and DOE, provides real time regulation of rotor speed by control of both generator torque and rotor torque. A variable speed generator system is used to provide both airgap torque control and reactive power control. The wind rotor is designed with segmented ailerons which are positioned to control blade torque. The central component of the control system, selected early in the design process, is a programmable controller used for sequencing, alarm monitoring, communication, and real time control. Development of requirements for use of aileron controlled blades and a variable speed generator required an analytical simulation that combined drivetrain, tower and blade elastic modes with wind disturbances and control behavior. An orderly two phase plan was used for controller software development. A microcomputer based turbine simulator was used to facilitate hardware and software integration and test.

  18. Extension-twist coupling of composite circular tubes with application to tilt rotor blade design

    Science.gov (United States)

    Nixon, Mark W.

    1987-01-01

    This investigation was conducted to determine if twist deformation required for the design of full-scale extension-twist-coupled tilt-rotor blades can be achieved within material design limit loads, and to demonstrate the accuracy of a coupled-beam analysis in predicting twist deformations. Two extension-twist-coupled tilt-rotor blade designs were developed based on theoretically optimum aerodynamic twist distributions. The designs indicated a twist rate requirement of between .216 and .333 deg/in. Agreement between axial tests and analytical predictions was within 10 percent at design limit loads. Agreement between the torsion tests and predictions was within 11 percent.

  19. A new sensitivity analysis for structural optimization of composite rotor blades

    Science.gov (United States)

    Venkatesan, C.; Friedmann, P. P.; Yuan, Kuo-An

    1993-01-01

    This paper presents a detailed mathematical derivation of the sensitivity derivatives for the structural dynamic, aeroelastic stability and response characteristics of a rotor blade in hover and forward flight. The formulation is denoted by the term semianalytical approach, because certain derivatives have to be evaluated by a finite difference scheme. Using the present formulation, sensitivity derivatives for the structural dynamic and aeroelastic stability characteristics, were evaluated for both isotropic and composite rotor blades. Based on the results, useful conclusions are obtained regarding the relative merits of the semi-analytical approach, for calculating sensitivity derivatives, when compared to a pure finite difference approach.

  20. Utilization of fiber reinforced plastics in rotor blades of wind turbines. WF Information

    Energy Technology Data Exchange (ETDEWEB)

    1980-01-01

    In order to produce wind power plants of the future with high power (1-5 MW), the wind turbines are constructed with large rotor diameters (up to 145 m). The rotor blade has to be designed for a service life of at least 25 years. The fiber bonded or hybrid structure (metal + fiber composite material) is certainly attractive, especially in corrosive environment, compared to conventional metal constructions (steel or aluminum in welded, riveted, or bolted form). Light, rigid, and dynamically high-strength rotor blades can be built with fiber reinforced plastics. The present report gives a survey of the material problems arising in such plants.

  1. Boundary Layer Transition Detection on a Rotor Blade Using Rotating Mirror Thermography

    Science.gov (United States)

    Heineck, James T.; Schuelein, Erich; Raffel, Markus

    2014-01-01

    Laminar-to-turbulent transition on a rotor blade in hover has been imaged using an area-scan infrared camera. A new method for tracking a blade using a rotating mirror was employed. The mirror axis of rotation roughly corresponded to the rotor axis of rotation and the mirror rotational frequency is 1/2 that of the rotor. This permitted the use of cameras whose integration time was too long to prevent image blur due to the motion of the blade. This article will show the use of this method for a rotor blade at different collective pitch angles.

  2. A 200-kW wind turbine generator conceptual design study

    Science.gov (United States)

    1979-01-01

    A conceptual design study was conducted to define a 200 kW wind turbine power system configuration for remote applications. The goal was to attain an energy cost of 1 to 2 cents per kilowatt-hour at a 14-mph site (mean average wind velocity at an altitude of 30 ft.) The costs of the Clayton, New Mexico, Mod-OA (200-kW) were used to identify the components, subsystems, and other factors that were high in cost and thus candidates for cost reduction. Efforts devoted to developing component and subsystem concepts and ideas resulted in a machine concept that is considerably simpler, lighter in weight, and lower in cost than the present Mod-OA wind turbines. In this report are described the various innovations that contributed to the lower cost and lighter weight design as well as the method used to calculate the cost of energy.

  3. On Rotor-Blade Deterioration and Pressure Losses in a Gas-Turbine ...

    African Journals Online (AJOL)

    blade deterioration and pressure losses in a gas-turbine plant. This was achieved ... Rotor-blade deterioration result in 1.2 percent drop in pressure ratio across the compressor, with a corresponding drop in isentropic efficiency from 0.83 to 0.72.

  4. Which way is the wind blowing for GRP? Materials and processes for manufacturing rotor blades

    Energy Technology Data Exchange (ETDEWEB)

    Bittmann, E. [Werkstoff and Struktur, Herreth (Germany)

    2002-11-01

    The material technology for the production of large-area rotor blades made of glass reinforced plastics (GRP) constitutes an important milestone in development. Customised resin systems, flexible, automated processing methods and high component quality document the progress made in the wind power industry. (orig.)

  5. Composite structure of helicopter rotor blades studied by neutron- and X-ray radiography

    International Nuclear Information System (INIS)

    Balasko, M.; Veres, I.; Molnar, Gy.; Balasko, Zs.; Svab, E.

    2004-01-01

    In order to inspect the possible defects in the composite structure of helicopter rotor blades combined neutron- and X-ray radiography investigations were performed at the Budapest Research Reactor. Imperfections in the honeycomb structure, resin rich or starved areas at the core-honeycomb surfaces, inhomogeneities at the adhesive filling and water percolation at the sealing interfaces of the honeycomb sections were discovered

  6. Composite structure of helicopter rotor blades studied by neutron- and X-ray radiography

    Science.gov (United States)

    Balaskó, M.; Veres, I.; Molnár, Gy.; Balaskó, Zs.; Sváb, E.

    2004-07-01

    In order to inspect the possible defects in the composite structure of helicopter rotor blades combined neutron- and X-ray radiography investigations were performed at the Budapest Research Reactor. Imperfections in the honeycomb structure, resin rich or starved areas at the core-honeycomb surfaces, inhomogeneities at the adhesive filling and water percolation at the sealing interfaces of the honeycomb sections were discovered.

  7. Genetic fuzzy system for online structural health monitoring of composite helicopter rotor blades

    Science.gov (United States)

    Pawar, Prashant M.; Ganguli, Ranjan

    2007-07-01

    A structural health monitoring (SHM) methodology is developed for composite rotor blades. An aeroelastic analysis of composite rotor blades based on the finite element method in space and time and with implanted matrix cracking and debonding/delamination damage is used to obtain measurable system parameters such as blade response, loads and strains. A rotor blade with a two-cell airfoil section and [0/±45/90]s family of laminates is used for numerical simulations. The model based measurements are contaminated with noise to simulate real data. Genetic fuzzy systems (GFS) are developed for global online damage detection using displacement and force-based measurement deviations between damaged and undamaged conditions and for local online damage detection using strains. It is observed that the success rate of the GFS depends on number of measurements, type of measurements and training and testing noise level. The GFS work quite well with noisy data and is recommended for online SHM of composite helicopter rotor blades.

  8. Process Modeling of Composite Materials for Wind-Turbine Rotor Blades: Experiments and Numerical Modeling

    Directory of Open Access Journals (Sweden)

    Birgit Wieland

    2017-10-01

    Full Text Available The production of rotor blades for wind turbines is still a predominantly manual process. Process simulation is an adequate way of improving blade quality without a significant increase in production costs. This paper introduces a module for tolerance simulation for rotor-blade production processes. The investigation focuses on the simulation of temperature distribution for one-sided, self-heated tooling and thick laminates. Experimental data from rotor-blade production and down-scaled laboratory tests are presented. Based on influencing factors that are identified, a physical model is created and implemented as a simulation. This provides an opportunity to simulate temperature and cure-degree distribution for two-dimensional cross sections. The aim of this simulation is to support production processes. Hence, it is modelled as an in situ simulation with direct input of temperature data and real-time capability. A monolithic part of the rotor blade, the main girder, is used as an example for presenting the results.

  9. A practical approach to fracture analysis at the trailing edge of wind turbine rotor blades

    DEFF Research Database (Denmark)

    Eder, Martin Alexander; Bitsche, Robert; Nielsen, Magda

    2014-01-01

    Wind turbine rotor blades are commonly manufactured from composite materials by a moulding process. Typically, the wind turbine blade is produced in two halves, which are eventually adhesively joined along their edges. Investigations of operating wind turbine blades show that debonding...

  10. Fatigue life prediction and strength degradation of wind turbine rotor blade composites

    NARCIS (Netherlands)

    Nijssen, R.P.L.

    2006-01-01

    Wind turbine rotor blades are subjected to a large number of highly variable loads, but life predictions are typically based on constant amplitude fatigue behaviour. Therefore, it is important to determine how service life under variable amplitude fatigue can be estimated from constant amplitude

  11. Preliminary structural design of composite main rotor blades for minimum weight

    Science.gov (United States)

    Nixon, Mark W.

    1987-01-01

    A methodology is developed to perform minimum weight structural design for composite or metallic main rotor blades subject to aerodynamic performance, material strength, autorotation, and frequency constraints. The constraints and load cases are developed such that the final preliminary rotor design will satisfy U.S. Army military specifications, as well as take advantage of the versatility of composite materials. A minimum weight design is first developed subject to satisfying the aerodynamic performance, strength, and autorotation constraints for all static load cases. The minimum weight design is then dynamically tuned to avoid resonant frequencies occurring at the design rotor speed. With this methodology, three rotor blade designs were developed based on the geometry of the UH-60A Black Hawk titanium-spar rotor blade. The first design is of a single titanium-spar cross section, which is compared with the UH-60A Black Hawk rotor blade. The second and third designs use single and multiple graphite/epoxy-spar cross sections. These are compared with the titanium-spar design to demonstrate weight savings from use of this design methodology in conjunction with advanced composite materials.

  12. Process Modeling of Composite Materials for Wind-Turbine Rotor Blades: Experiments and Numerical Modeling.

    Science.gov (United States)

    Wieland, Birgit; Ropte, Sven

    2017-10-05

    The production of rotor blades for wind turbines is still a predominantly manual process. Process simulation is an adequate way of improving blade quality without a significant increase in production costs. This paper introduces a module for tolerance simulation for rotor-blade production processes. The investigation focuses on the simulation of temperature distribution for one-sided, self-heated tooling and thick laminates. Experimental data from rotor-blade production and down-scaled laboratory tests are presented. Based on influencing factors that are identified, a physical model is created and implemented as a simulation. This provides an opportunity to simulate temperature and cure-degree distribution for two-dimensional cross sections. The aim of this simulation is to support production processes. Hence, it is modelled as an in situ simulation with direct input of temperature data and real-time capability. A monolithic part of the rotor blade, the main girder, is used as an example for presenting the results.

  13. Superconducting wind turbine generators

    DEFF Research Database (Denmark)

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

    2010-01-01

    , the main challenge of the superconducting direct drive technology is to prove that the reliability is superior to the alternative drive trains based on gearboxes or permanent magnets. A strategy of successive testing of superconducting direct drive trains in real wind turbines of 10 kW, 100 kW, 1 MW and 10......We have examined the potential of 10 MW superconducting direct drive generators to enter the European offshore wind power market and estimated that the production of about 1200 superconducting turbines until 2030 would correspond to 10% of the EU offshore market. The expected properties of future...... offshore turbines of 8 and 10 MW have been determined from an up-scaling of an existing 5 MW turbine and the necessary properties of the superconducting drive train are discussed. We have found that the absence of the gear box is the main benefit and the reduced weight and size is secondary. However...

  14. Superconducting wind turbine generators

    International Nuclear Information System (INIS)

    Abrahamsen, A B; Seiler, E; Zirngibl, T; Andersen, N H; Mijatovic, N; Traeholt, C; Pedersen, N F; Oestergaard, J; Noergaard, P B

    2010-01-01

    We have examined the potential of 10 MW superconducting direct drive generators to enter the European offshore wind power market and estimated that the production of about 1200 superconducting turbines until 2030 would correspond to 10% of the EU offshore market. The expected properties of future offshore turbines of 8 and 10 MW have been determined from an up-scaling of an existing 5 MW turbine and the necessary properties of the superconducting drive train are discussed. We have found that the absence of the gear box is the main benefit and the reduced weight and size is secondary. However, the main challenge of the superconducting direct drive technology is to prove that the reliability is superior to the alternative drive trains based on gearboxes or permanent magnets. A strategy of successive testing of superconducting direct drive trains in real wind turbines of 10 kW, 100 kW, 1 MW and 10 MW is suggested to secure the accumulation of reliability experience. Finally, the quantities of high temperature superconducting tape needed for a 10 kW and an extreme high field 10 MW generator are found to be 7.5 km and 1500 km, respectively. A more realistic estimate is 200-300 km of tape per 10 MW generator and it is concluded that the present production capacity of coated conductors must be increased by a factor of 36 by 2020, resulting in a ten times lower price of the tape in order to reach a realistic price level for the superconducting drive train.

  15. Simulation of unsteady flows through stator and rotor blades of a gas turbine using the Chimera method

    Science.gov (United States)

    Nakamura, S.; Scott, J. N.

    1993-01-01

    A two-dimensional model to solve compressible Navier-Stokes equations for the flow through stator and rotor blades of a turbine is developed. The flow domains for the stator and rotor blades are coupled by the Chimera method that makes grid generation easy and enhances accuracy because the area of the grid that have high turning of grid lines or high skewness can be eliminated from the computational domain after the grids are generated. The results of flow computations show various important features of unsteady flows including the acoustic waves interacting with boundary layers, Karman vortex shedding from the trailing edge of the stator blades, pulsating incoming flow to a rotor blade from passing stator blades, and flow separation from both suction and pressure sides of the rotor blades.

  16. On the impact of multi-axial stress states on trailing edge bondlines in wind turbine rotor blades

    OpenAIRE

    Castelos, Pablo Noever; Balzani, Claudio

    2016-01-01

    For a reliable design of wind turbine systems all of their components have to be designed to withstand the loads appearing in the turbine's lifetime. When performed in an integral manner this is called systems engineering, and is exceptionally important for components that have an impact on the entire wind turbine system, such as the rotor blade. Bondlines are crucial subcomponents of rotor blades, but they are not much recognized in the wind energy research community. However, a bondline fai...

  17. Aerodynamic analysis of potential use of flow control devices on helicopter rotor blades

    International Nuclear Information System (INIS)

    Tejero, F; Doerffer, P; Szulc, O

    2014-01-01

    The interest in the application of flow control devices has been rising in the last years. Recently, several passive streamwise vortex generators have been analysed in a configuration of a curved wall nozzle within the framework of the UFAST project (Unsteady Effects of Shock Wave Induced Separation, 2005 – 2009). Experimental and numerical results proved that the technology is effective in delaying flow separation. The numerical investigation has been extended to helicopter rotor blades in hover and forward flight applying the FLOWer solver (RANS approach) implementing the chimera overlapping grids technique and high performance computing. CFD results for hover conditions confirm that the proposed passive control method reduces the flow separation increasing the thrust over power consumption. The paper presents the numerical validation for both states of flight and the possible implementation of RVGs on helicopter rotor blades.

  18. Performance of a Low Speed Axial Compressor Rotor Blade Row under Different Inlet Distortions

    Directory of Open Access Journals (Sweden)

    R. Taghavi Zenouz

    2017-05-01

    Full Text Available Responses of an axial compressor isolated rotor blade row to various inlet distortions have been investigated utilizing computational fluid dynamic technique. Distortions have been imposed by five screens of different geometries, but with the same blockage ratio. These screens were embedded upstream of the rotor blade row. Flow fields are simulated in detail for compressor design point and near stall conditions. Performance curves for distorted cases are extracted and compared to the undisturbed case. Flow simulations and consequent performance characteristics show that the worst cases belong to non-symmetric blockages, i.e., those of partial circumferential configurations. These cases produce the largest wakes which can disturb the flow, considerably. Superior performances correspond to the inner and outer continuous circumferential distortion screens. Since, they produce no significant disturbances to the main flow in comparison to the non-symmetric screens.

  19. Active Control of Parametric Vibrations in Coupled Rotor-Blade Systems

    DEFF Research Database (Denmark)

    Christensen, Rene Hardam; Santos, Ilmar

    2003-01-01

    of modes. The designed control scheme is applied to a coupled rotor-blade system and dynamic responses are numerically evaluated. Such responses show that the vibrations are efficiently reduced. Frequency response diagrams demonstrate that both basis and parametric vibration modes are significantly...... the model becomes periodic-variant. In order to reduce basis as well as parametric vibrations by means of active control in such systems a time-variant control strategy has to be adopted. This paper presents a methodology for designing an active controller to reduce vibrations in a coupled rotor......-blade system. The main aim is to control blade as well as hub vibrations in such a system by means of active control with focus on reducing the parametric vibration. A periodic state feedback controller is designed by transforming the system into a linear time-invariant form. Using this a controller...

  20. A simulation study of active feedback supression of dynamic response in helicopter rotor blades

    Science.gov (United States)

    Kana, D. D.; Bessey, R. L.; Dodge, F. T.

    1975-01-01

    A parameter study is presented for active feedback control applied to a helicopter rotor blade during forward flight. The study was performed on an electromechanical apparatus which included a mechanical model rotor blade and electronic analog simulation of interaction between blade deflections and aerodynamic loading. Blade response parameters were obtained for simulated vortex impinging at the blade tip at one pulse per revolution, and for a pulse which traveled from the blade tip toward its root. Results show that the response in a 1 - 10-per-rev frequency band is diminished by the feedback action, but at the same time responses at frequencies above 10-per-rev become increasingly more prominent with increased feedback amplitude, and can even lead to instability at certain levels. It appears that the latter behavior results from limitations of the laboratory simulation apparatus, rather than genuine potential behavior for a prototype helicopter.

  1. Influence of cross section variations on the structural behaviour of composite rotor blades

    Science.gov (United States)

    Rapp, Helmut; Woerndle, Rudolf

    1991-09-01

    A highly sophisticated structural analysis is required for helicopter rotor blades with nonhomogeneous cross sections made from nonisotropic material. Combinations of suitable analytical techniques with FEM-based techniques permit a cost effective and sufficiently accurate analysis of these complicated structures. It is determined that in general the 1D engineering theory of bending combined with 2D theories for determining the cross section properties is sufficient to describe the structural blade behavior.

  2. Stress analysis of advanced attack helicopter composite main rotor blade root end lug

    Science.gov (United States)

    Baker, D. J.

    1982-01-01

    Stress analysis of the Advanced Attack Helicopter (AAH) composite main rotor blade root end lug is described. The stress concentration factor determined from a finite element analysis is compared to an empirical value used in the lug design. The analysis and test data indicate that the stress concentration is primarily a function of configuration and independent of the range of material properties typical of Kevlar-49/epoxy and glass epoxy.

  3. A new experimental method for determining local airloads on rotor blades in forward flight

    Science.gov (United States)

    Berton, E.; Maresca, C.; Favier, D.

    This paper presents a new approach for determining local airloads on helicopter rotor blade sections in forward flight. The method is based on the momentum equation in which all the terms are expressed by means of the velocity field measured by a laser Doppler velocimeter. The relative magnitude of the different terms involved in the momentum and Bernoulli equations is estimated and the results are encouraging.

  4. An innovative medium speed wind turbine rotor blade design for low wind regime (electrical power generation)

    International Nuclear Information System (INIS)

    Abas Abd Wahab; Chong Wen Tong

    2001-01-01

    This paper describes the preliminary study of a small-scale wind turbine rotor blade (a low wind speed region turbine). A new wind turbine rotor blade (AE2 blade) for stand alone system has been conceptualized, designed, constructed and tested. The system is a reduced size prototype (half-scaled) to develop an efficient (adapted to Malaysian wind conditions)and cost effective wind energy conversion system (WECS) with local design and production technique. The blades were constructed from aluminium sheet with metal blending technique. The layout and design of rotor blade, its innovative features and test results are presented. Results from indoor test showed that the advantages of AE2 blade in low speed, with the potential of further improvements. The best rotor efficiency, C P attained with simple AE2 blades rotor (number of blade = 3) was 37.3% (Betz efficiency = 63%) at tip speed ratio (TSR) = 3.6. From the fabrication works and indoor testing, the AE2 blade rotor has demonstrated its structural integrity (ease of assembly and transportation), simplicity, acceptable performance and low noise level. (Author)

  5. Non-Destructive Measurement Methods (Neutron-, X-ray Radiography, Vibration Diagnostics and Ultrasound) in the Inspection of Helicopter Rotor Blades

    National Research Council Canada - National Science Library

    Balasko, M; Endroczi, G; Tarnai, Gy; Veres, I; Molnar, Gy; Svab, E

    2005-01-01

    The experiments regarding structural failures in helicopter rotor blade's composite structures causing water penetrations and bypasses were performed at the Dynamic Radiography Station (DRS) of the Budapest...

  6. Dermal uptake and excretion of 4,4'-methylenedianiline during rotor blade production in helicopter industry--an intervention study.

    Science.gov (United States)

    Weiss, Tobias; Schuster, Hubert; Müller, Johannes; Schaller, Karl-Heinz; Drexler, Hans; Angerer, Jürgen; Käfferlein, Heiko U

    2011-10-01

    Workers using composite materials by fibre reinforced laminate technology are exposed to 4,4'-methylenedianiline (MDA), a liver toxicant and suspected human carcinogen, during the production of rotor blades in helicopter industry. The aim of the study presented here was to assess the internal dose of MDA and the suitability of various personal protection measures at the workplace. Ambient monitoring and biological monitoring was carried out by analysing MDA in air and urine samples in seven workers of a highly specialized workplace (rotor blade production). Three different concepts of personal protection measures were applied to study the route of uptake and to evaluate strategies in decreasing workplace exposure. In addition, elimination kinetics of MDA was studied in three workers who were exposed to MDA on three consecutive working days. Ambient monitoring consistently provided air levels at or below the limit of quantification of 0.1 μg m(-3). Nevertheless, MDA was detected in 89% of all post-shift urine samples and median concentration was 4.2 μg l(-1). MDA in urine were >20 times higher than expected on data from ambient monitoring alone. A significant decrease in exposure could be achieved when workers have worn MDA-protective overalls in combination with MDA-protective gloves and a splash protection shield (from 9.8 μg l(-1) down to 3.7 μg l(-1)). The results show that MDA is taken up primarily via the skin at the workplaces under study. The excretion of MDA in urine was observed to be delayed after dermal exposure. Exposure assessment of MDA should be carried out by biological monitoring rather than ambient monitoring. For this purpose, urine samples midweek or at the end of the week should be used based on the observed delay in the excretion of MDA after dermal absorption. Uptake of MDA via the skin could not be completely avoided even if state-of-the-art personal protection measures were applied.

  7. Advanced grid-stiffened composite shells for applications in heavy-lift helicopter rotor blade spars

    Science.gov (United States)

    Narayanan Nampy, Sreenivas

    Modern rotor blades are constructed using composite materials to exploit their superior structural performance compared to metals. Helicopter rotor blade spars are conventionally designed as monocoque structures. Blades of the proposed Heavy Lift Helicopter are envisioned to be as heavy as 800 lbs when designed using the monocoque spar design. A new and innovative design is proposed to replace the conventional spar designs with light weight grid-stiffened composite shell. Composite stiffened shells have been known to provide excellent strength to weight ratio and damage tolerance with an excellent potential to reduce weight. Conventional stringer--rib stiffened construction is not suitable for rotor blade spars since they are limited in generating high torsion stiffness that is required for aeroelastic stability of the rotor. As a result, off-axis (helical) stiffeners must be provided. This is a new design space where innovative modeling techniques are needed. The structural behavior of grid-stiffened structures under axial, bending, and torsion loads, typically experienced by rotor blades need to be accurately predicted. The overall objective of the present research is to develop and integrate the necessary design analysis tools to conduct a feasibility study in employing grid-stiffened shells for heavy-lift rotor blade spars. Upon evaluating the limitations in state-of-the-art analytical models in predicting the axial, bending, and torsion stiffness coefficients of grid and grid-stiffened structures, a new analytical model was developed. The new analytical model based on the smeared stiffness approach was developed employing the stiffness matrices of the constituent members of the grid structure such as an arch, helical, or straight beam representing circumferential, helical, and longitudinal stiffeners. This analysis has the capability to model various stiffening configurations such as angle-grid, ortho-grid, and general-grid. Analyses were performed using an

  8. Multidisciplinary Optimization of Tilt Rotor Blades Using Comprehensive Composite Modeling Technique

    Science.gov (United States)

    Chattopadhyay, Aditi; McCarthy, Thomas R.; Rajadas, John N.

    1997-01-01

    An optimization procedure is developed for addressing the design of composite tilt rotor blades. A comprehensive technique, based on a higher-order laminate theory, is developed for the analysis of the thick composite load-carrying sections, modeled as box beams, in the blade. The theory, which is based on a refined displacement field, is a three-dimensional model which approximates the elasticity solution so that the beam cross-sectional properties are not reduced to one-dimensional beam parameters. Both inplane and out-of-plane warping are included automatically in the formulation. The model can accurately capture the transverse shear stresses through the thickness of each wall while satisfying stress free boundary conditions on the inner and outer surfaces of the beam. The aerodynamic loads on the blade are calculated using the classical blade element momentum theory. Analytical expressions for the lift and drag are obtained based on the blade planform with corrections for the high lift capability of rotor blades. The aerodynamic analysis is coupled with the structural model to formulate the complete coupled equations of motion for aeroelastic analyses. Finally, a multidisciplinary optimization procedure is developed to improve the aerodynamic, structural and aeroelastic performance of the tilt rotor aircraft. The objective functions include the figure of merit in hover and the high speed cruise propulsive efficiency. Structural, aerodynamic and aeroelastic stability criteria are imposed as constraints on the problem. The Kreisselmeier-Steinhauser function is used to formulate the multiobjective function problem. The search direction is determined by the Broyden-Fletcher-Goldfarb-Shanno algorithm. The optimum results are compared with the baseline values and show significant improvements in the overall performance of the tilt rotor blade.

  9. Real-time estimation of helicopter rotor blade kinematics through measurement of rotation induced acceleration

    Science.gov (United States)

    Allred, C. Jeff; Churchill, David; Buckner, Gregory D.

    2017-07-01

    This paper presents a novel approach to monitoring rotor blade flap, lead-lag and pitch using an embedded gyroscope and symmetrically mounted MEMS accelerometers. The central hypothesis is that differential accelerometer measurements are proportional only to blade motion; fuselage acceleration and blade bending are inherently compensated for. The inverse kinematic relationships (from blade position to acceleration and angular rate) are derived and simulated to validate this hypothesis. An algorithm to solve the forward kinematic relationships (from sensor measurement to blade position) is developed using these simulation results. This algorithm is experimentally validated using a prototype device. The experimental results justify continued development of this kinematic estimation approach.

  10. Anisotropic piezoelectric twist actuation of helicopter rotor blades: Aeroelastic analysis and design optimization

    Science.gov (United States)

    Wilkie, William Keats

    1997-12-01

    An aeroelastic model suitable for control law and preliminary structural design of composite helicopter rotor blades incorporating embedded anisotropic piezoelectric actuator laminae is developed. The aeroelasticity model consists of a linear, nonuniform beam representation of the blade structure, including linear piezoelectric actuation terms, coupled with a nonlinear, finite-state unsteady aerodynamics model. A Galerkin procedure and numerical integration in the time domain are used to obtain a soluti An aeroelastic model suitable for control law and preliminary structural design of composite helicopter rotor blades incorporating embedded anisotropic piezoelectric actuator laminae is developed. The aeroelasticity model consists of a linear, nonuniform beam representation of the blade structure, including linear piezoelectric actuation terms, coupled with a nonlinear, finite-state unsteady aerodynamics model. A Galerkin procedure and numerical integration in the time domain are used to obtain amited additional piezoelectric material mass, it is shown that blade twist actuation approaches which exploit in-plane piezoelectric free-stain anisotropies are capable of producing amplitudes of oscillatory blade twisting sufficient for rotor vibration reduction applications. The second study examines the effectiveness of using embedded piezoelectric actuator laminae to alleviate vibratory loads due to retreating blade stall. A 10 to 15 percent improvement in dynamic stall limited forward flight speed, and a 5 percent improvement in stall limited rotor thrust were numerically demonstrated for the active twist rotor blade relative to a conventional blade design. The active twist blades are also demonstrated to be more susceptible than the conventional blades to dynamic stall induced vibratory loads when not operating with twist actuation. This is the result of designing the active twist blades with low torsional stiffness in order to maximize piezoelectric twist authority

  11. Effect of incidence angle on the wake turbulence of a turbine rotor blade

    International Nuclear Information System (INIS)

    Chang, Sung Il; Lee, Sang Woo

    2005-01-01

    This paper describes effects of incidence angle on the wake turbulent flow of a high-turning turbine rotor blade. For three incidence angles of -5, 0 and 5 degrees, energy spectra as well as profiles of mean velocity magnitude and turbulence intensity at mid-span are reported in the wake. Vortex shedding frequencies are obtained from the energy spectra. The result shows that as the incidence angle changes from -5 to 5 degrees, the suction-side wake tends to be widened and the deviation angle is increased. Strouhal numbers based on the shedding frequencies have a nearly constant value, regardless of the tested incidence angles

  12. The effect of forward skewed rotor blades on aerodynamic and aeroacoustic performance of axial-flow fan

    Science.gov (United States)

    Wei, Jun; Zhong, Fangyuan

    Based on comparative experiment, this paper deals with using tangentially skewed rotor blades in axial-flow fan. It is seen from the comparison of the overall performance of the fan with skewed bladed rotor and radial bladed rotor that the skewed blades operate more efficiently than the radial blades, especially at low volume flows. Meanwhile, decrease in pressure rise and flow rate of axial-flow fan with skewed rotor blades is found. The rotor-stator interaction noise and broadband noise of axial-flow fan are reduced with skewed rotor blades. Forward skewed blades tend to reduce the accumulation of the blade boundary layer in the tip region resulting from the effect of centrifugal forces. The turning of streamlines from the outer radius region into inner radius region in blade passages due to the radial component of blade forces of skewed blades is the main reason for the decrease in pressure rise and flow rate.

  13. Optimal Design and Acoustic Assessment of Low-Vibration Rotor Blades

    Directory of Open Access Journals (Sweden)

    G. Bernardini

    2016-01-01

    Full Text Available An optimal procedure for the design of rotor blade that generates low vibratory hub loads in nonaxial flow conditions is presented and applied to a helicopter rotor in forward flight, a condition where vibrations and noise become severe. Blade shape and structural properties are the design parameters to be identified within a binary genetic optimization algorithm under aeroelastic stability constraint. The process exploits an aeroelastic solver that is based on a nonlinear, beam-like model, suited for the analysis of arbitrary curved-elastic-axis blades, with the introduction of a surrogate wake inflow model for the analysis of sectional aerodynamic loads. Numerical results are presented to demonstrate the capability of the proposed approach to identify low vibratory hub loads rotor blades as well as to assess the robustness of solution at off-design operating conditions. Further, the aeroacoustic assessment of the rotor configurations determined is carried out in order to examine the impact of low-vibration blade design on the emitted noise field.

  14. Flap-lag-torsional dynamics of helicopter rotor blades in forward flight

    Science.gov (United States)

    Crespodasilva, M. R. M.

    1986-01-01

    A perturbation/numerical methodology to analyze the flap-lead/lag motion of a centrally hinged spring restrained rotor blade that is valid for both hover and for forward flight was developed. The derivation of the nonlinear differential equations of motion and the analysis of the stability of the steady state response of the blade were conducted entirely in a Symbolics 3670 Machine using MACSYMA to perform all the lengthy symbolic manipulations. It also includes generation of the fortran codes and plots of the results. The Floquet theory was also applied to the differential equations of motion in order to compare results with those obtained from the perturbation analysis. The results obtained from the perturbation methodology and from Floquet theory were found to be very close to each other, which demonstrates the usefullness of the perturbation methodology. Another problem under study consisted in the analysis of the influence of higher order terms in the response and stability of a flexible rotor blade in forward flight using Computerized Symbolic Manipulation and a perturbation technique to bypass the Floquet theory. The derivation of the partial differential equations of motion is presented.

  15. Aeroelasticity and structural optimization of composite helicopter rotor blades with swept tips

    Science.gov (United States)

    Yuan, K. A.; Friedmann, P. P.

    1995-01-01

    This report describes the development of an aeroelastic analysis capability for composite helicopter rotor blades with straight and swept tips, and its application to the simulation of helicopter vibration reduction through structural optimization. A new aeroelastic model is developed in this study which is suitable for composite rotor blades with swept tips in hover and in forward flight. The hingeless blade is modeled by beam type finite elements. A single finite element is used to model the swept tip. Arbitrary cross-sectional shape, generally anisotropic material behavior, transverse shears and out-of-plane warping are included in the blade model. The nonlinear equations of motion, derived using Hamilton's principle, are based on a moderate deflection theory. Composite blade cross-sectbnal properties are calculated by a separate linear, two-dimensional cross section analysis. The aerodynamic loads are obtained from quasi-steady, incompressible aerodynamics, based on an implicit formulation. The trim and steady state blade aeroelastic response are solved in a fully coupled manner. In forward flight, where the blade equations of motion are periodic, the coupled trim-aeroelastic response solution is obtained from the harmonic balance method. Subsequently, the periodic system is linearized about the steady state response, and its stability is determined from Floquet theory.

  16. Aeroelastic Analysis of Helicopter Rotor Blades Incorporating Anisotropic Piezoelectric Twist Actuation

    Science.gov (United States)

    Wilkie, W. Keats; Belvin, W. Keith; Park, K. C.

    1996-01-01

    A simple aeroelastic analysis of a helicopter rotor blade incorporating embedded piezoelectric fiber composite, interdigitated electrode blade twist actuators is described. The analysis consists of a linear torsion and flapwise bending model coupled with a nonlinear ONERA based unsteady aerodynamics model. A modified Galerkin procedure is performed upon the rotor blade partial differential equations of motion to develop a system of ordinary differential equations suitable for dynamics simulation using numerical integration. The twist actuation responses for three conceptual fullscale blade designs with realistic constraints on blade mass are numerically evaluated using the analysis. Numerical results indicate that useful amplitudes of nonresonant elastic twist, on the order of one to two degrees, are achievable under one-g hovering flight conditions for interdigitated electrode poling configurations. Twist actuation for the interdigitated electrode blades is also compared with the twist actuation of a conventionally poled piezoelectric fiber composite blade. Elastic twist produced using the interdigitated electrode actuators was found to be four to five times larger than that obtained with the conventionally poled actuators.

  17. An aeroelastic analysis of helicopter rotor blades incorporating piezoelectric fiber composite twist actuation

    Science.gov (United States)

    Wilkie, W. Keats; Park, K. C.

    1996-01-01

    A simple aeroelastic analysis of a helicopter rotor blade incorporating embedded piezoelectric fiber composite, interdigitated electrode blade twist actuators is described. The analysis consist of a linear torsion and flapwise bending model coupled with a nonlinear ONERA based unsteady aerodynamics model. A modified Galerkin procedure is performed upon the rotor blade partial differential equations of motion to develop a system of ordinary differential equations suitable for numerical integration. The twist actuation responses for three conceptual full-scale blade designs with realistic constraints on blade mass are numerically evaluated using the analysis. Numerical results indicate that useful amplitudes of nonresonant elastic twist, on the order of one to two degrees, are achievable under one-g hovering flight conditions for interdigitated electrode poling configurations. Twist actuation for the interdigitated electrode blades is also compared with the twist actuation of a conventionally poled piezoelectric fiber composite blade. Elastic twist produced using the interdigitated electrode actuators was found to be four to five times larger than that obtained with the conventionally poled actuators.

  18. Classification of defects in honeycomb composite structure of helicopter rotor blades

    International Nuclear Information System (INIS)

    Balasko, M.; Svab, E.; Molnar, Gy.; Veres, I.

    2005-01-01

    The use of non-destructive testing methods to qualify the state of rotor blades with respect to their expected flight hours, with the aim to extend their lifetime without any risk of breakdown, is an important financial demand. In order to detect the possible defects in the composite structure of Mi-8 and Mi-24 type helicopter rotor blades used by the Hungarian Army, we have performed combined neutron- and X-ray radiography measurements at the Budapest Research Reactor. Several types of defects were detected, analysed and typified. Among the most frequent and important defects observed were cavities, holes and or cracks in the sealing elements on the interface of the honeycomb structure and the section boarders. Inhomogeneities of the resin materials (resin-rich or starved areas) at the core-honeycomb surfaces proved to be an other important point. Defects were detected at the adhesive filling, and water percolation was visualized at the sealing interfaces of the honeycomb sections. Corrosion effects, and metal inclusions have also been detected

  19. Classification of defects in honeycomb composite structure of helicopter rotor blades

    Science.gov (United States)

    Balaskó, M.; Sváb, E.; Molnár, Gy.; Veres, I.

    2005-04-01

    The use of non-destructive testing methods to qualify the state of rotor blades with respect to their expected flight hours, with the aim to extend their lifetime without any risk of breakdown, is an important financial demand. In order to detect the possible defects in the composite structure of Mi-8 and Mi-24 type helicopter rotor blades used by the Hungarian Army, we have performed combined neutron- and X-ray radiography measurements at the Budapest Research Reactor. Several types of defects were detected, analysed and typified. Among the most frequent and important defects observed were cavities, holes and/or cracks in the sealing elements on the interface of the honeycomb structure and the section boarders. Inhomogeneities of the resin materials (resin-rich or starved areas) at the core-honeycomb surfaces proved to be an other important point. Defects were detected at the adhesive filling, and water percolation was visualized at the sealing interfaces of the honeycomb sections. Corrosion effects, and metal inclusions have also been detected.

  20. Aeroelastic modeling of composite rotor blades with straight and swept tips

    Science.gov (United States)

    Yuan, Kuo-An; Friedmann, Peretz P.; Venkatesan, Comandur

    1992-01-01

    This paper presents an analytical study of the aeroelastic behavior of composite rotor blades with straight and swept tips. The blade is modeled by beam type finite elements. A single finite element is used to model the swept tip. The nonlinear equations of motion for the FEM are derived using Hamilton's principle and based on a moderate deflection theory and accounts for: arbitrary cross-sectional shape, pretwist, generally anisotropic material behavior, transverse shears and out-of-plane warping. Numerical results illustrating the effects of tip sweep, anhedral and composite ply orientation on blade aeroelastic behavior are presented. It is shown that composite ply orientation has a substantial effect on blade stability. At low thrust conditions, certain ply orientations can cause instability in the lag mode. The flap-torsion coupling associated with tip sweep can also induce aeroelastic instability in the blade. This instability can be removed by appropriate ply orientation in the composite construction. These results illustrate the inherent potential for aeroelastic tailoring present in composite rotor blades with swept tips, which still remains to be exploited in the design process.

  1. A multi-frequency fatigue testing method for wind turbine rotor blades

    Science.gov (United States)

    Eder, M. A.; Belloni, F.; Tesauro, A.; Hanis, T.

    2017-02-01

    Rotor blades are among the most delicate components of modern wind turbines. Reliability is a crucial aspect, since blades shall ideally remain free of failure under ultra-high cycle loading conditions throughout their designated lifetime of 20-25 years. Full-scale blade tests are the most accurate means to experimentally simulate damage evolution under operating conditions, and are therefore used to demonstrate that a blade type fulfils the reliability requirements to an acceptable degree of confidence. The state-of-the-art testing method for rotor blades in industry is based on resonance excitation where typically a rotating mass excites the blade close to its first natural frequency. During operation the blade response due to external forcing is governed by a weighted combination of its eigenmodes. Current test methodologies which only utilise the lowest eigenfrequency induce a fictitious damage where additional tuning masses are required to recover the desired damage distribution. Even with the commonly adopted amplitude upscaling technique fatigue tests remain a time-consuming and costly endeavour. The application of tuning masses increases the complexity of the problem by lowering the natural frequency of the blade and therefore increasing the testing time. The novel method presented in this paper aims at shortening the duration of the state-of-the-art fatigue testing method by simultaneously exciting the blade with a combination of two or more eigenfrequencies. Taking advantage of the different shapes of the excited eigenmodes, the actual spatial damage distribution can be more realistically simulated in the tests by tuning the excitation force amplitudes rather than adding tuning masses. This implies that in portions of the blade the lowest mode is governing the damage whereas in others higher modes contribute more significantly due to their higher cycle count. A numerical feasibility study based on a publicly available large utility rotor blade is used to

  2. Design and optimization for strength and integrity of tidal turbine rotor blades

    International Nuclear Information System (INIS)

    Liu, Pengfei; Veitch, Brian

    2012-01-01

    Tidal turbine rotor blade fractures and failures have resulted in substantial damage and hence cost of repair and recovery. The present work presents a rotor blade design and optimization method to address the blade structural strength design problem. The generic procedure is applicable to both turbine rotors and propellers. The optimization method seeks an optimum blade thickness distribution across the span with a prescribed constant safety factor for all the blade sections. This optimization procedure serves two purposes: while maintaining the required structural strength and integrity for an ultimate inflow speed, it aims to reduce the material to a minimum and to maintain power generation efficiency or improve the hydrodynamic efficiency. The value of the chosen minimum safety factor depends on the actual working conditions of the turbine in which the sectional peak loading and frequency are used: the harsher the environment, the larger the required safety factor. An engineering software tool with both hydrodynamic and structural capabilities was required to predict the instantaneous loading acting on all the blade sections, as well as the strength of a local blade section with a given blade geometry and chosen material. A time-domain, 3D unsteady panel method was then implemented based on a marine propeller software tool and used to perform the optimization. A 3-blade 20-m tidal turbine that was prototyped in parallel with the current work for the Bay of Fundy was used as an example for optimization. The optimum thickness distribution for a required safety factor at the ultimate possible inflow speed resulted in 37.6% saving in blade material. The blade thickness and distribution as a function of a maximum inflow speed of 6 m/s is also presented. The blade material used in the example was taken as nickel–aluminium–bronze (NAB) but the procedure was developed to be applicable to propeller or turbine blades of basically any material. -- Highlights: ► A

  3. On the impact of multi-axial stress states on trailing edge bondlines in wind turbine rotor blades

    Science.gov (United States)

    Noever Castelos, Pablo; Balzani, Claudio

    2016-09-01

    For a reliable design of wind turbine systems all of their components have to be designed to withstand the loads appearing in the turbine's lifetime. When performed in an integral manner this is called systems engineering, and is exceptionally important for components that have an impact on the entire wind turbine system, such as the rotor blade. Bondlines are crucial subcomponents of rotor blades, but they are not much recognized in the wind energy research community. However, a bondline failure can lead to the loss of a rotor blade, and potentially of the entire turbine, and is extraordinarily relevant to be treated with strong emphasis when designing a wind turbine. Modern wind turbine rotor blades with lengths of 80 m and more offer a degree of flexibility that has never been seen in wind energy technology before. Large deflections result in high strains in the adhesive connections, especially at the trailing edge. The latest edition of the DNV GL guideline from end of 2015 demands a three-dimensional stress analysis of bondlines, whereas before an isolated shear stress proof was sufficient. In order to quantify the lack of safety from older certification guidelines this paper studies the influence of multi-axial stress states on the ultimate and fatigue load resistance of trailing edge adhesive bonds. For this purpose, detailed finite element simulations of the IWES IWT-7.5-164 reference wind turbine blades are performed. Different yield criteria are evaluated for the prediction of failure and lifetime. The results show that the multi-axial stress state is governed by span-wise normal stresses. Those are evidently not captured in isolated shear stress proofs, yielding non-conservative estimates of lifetime and ultimate load resistance. This finding highlights the importance to include a three-dimensional stress state in the failure analysis of adhesive bonds in modern wind turbine rotor blades, and the necessity to perform a three-dimensional characterization

  4. Design Of Rotor Blade For Vertical Axis Wind Turbine Using Double Aerofoil

    DEFF Research Database (Denmark)

    Chougule, Prasad; Ratkovich, Nicolas Rios; Kirkegaard, Poul Henning

    Nowadays, small vertical axis wind turbines are receiving more attention compared to horizontal wind turbines due to their suitability in urban use because they generate less noise, have bird free turbines and lower cost. There is few vertical axis wind turbines design with good power curve....... However, the efficiency of power extraction has not been improved. Therefore, an attempt has been made to utilize high lift technology in practice for vertical axis wind turbines in order to improve power efficiency. High lift is obtained by double aerofoil elements mainly used in aeroplane wing design....... In this current work two aerofoils are used to design a rotor blade for a vertical axis wind turbine to improve the power efficiency on the rotor. Double aerofoil blade design consists of a main aerofoil and a slat aerofoil. The parameters related to position and orientation of the slat aerofoil with respect...

  5. Development of a piezoelectric actuator for trailing-edge flap control of rotor blades

    Science.gov (United States)

    Straub, Friedrich K.; Ngo, Hieu T.; Anand, V.; Domzalski, David B.

    1999-06-01

    Piezoelectric actuator technology has now reached a level where macro-positioning applications in the context of smart structures can be considered. One application with high payoffs is vibration reduction, noise reduction, and performance improvements in helicopters. Integration of piezoelectric actuators in the rotor blade is attractive, since it attacks the problem at the source. The present paper covers the development of a piezoelectric actuator for trailing edge flap control on a 34-foot diameter helicopter main rotor. The design of an actuator using bi-axial stack columns, and its bench, shake, and spin testing are described. A series of enhancements lead to an improved version that, together with use of latest stack technology, meets the requirements. Next steps in this DARPA sponsored program are development of the actuator and full scale rotor system for wind tunnel testing in the NASA Ames 40 X 80 foot wind tunnel and flight testing on the MD Explorer.

  6. A new aeroelastic model for composite rotor blades with straight and swept tips

    Science.gov (United States)

    Yuan, Kuo-An; Friedmann, Peretz P.; Venkatesan, Comandur

    1992-01-01

    An analytical model for predicting the aeroelastic behavior of composite rotor blades with straight and swept tips is presented. The blade is modeled by beam type finite elements along the elastic axis. A single finite element is used to model the swept tip. The nonlinear equations of motion for the finite element model are derived using Hamilton's principle and based on a moderate deflection theory and accounts for: arbitrary cross-sectional shape, pretwist, generally anisotropic material behavior, transverse shears and out-of-plane warping. Numerical results illustrating the effects of tip sweep, anhedral and composite ply orientation on blade aeroelastic behavior are presented. Tip sweep can induce aeroelastic instability by flap-twist coupling. Tip anhedral causes lag-torsion and flap-axial couplings, however, its effects on blade stability is less pronounced than the effect due to sweep. Composite ply orientation has a substantial effect on blade stability.

  7. Design of a fibrous composite preform for wind turbine rotor blades

    DEFF Research Database (Denmark)

    Hansen, Jens Zangenberg; Brøndsted, Povl; Kofoed, M.

    2014-01-01

    The present work addresses the different factors and challenges one must cope with in the design process of a composite preform used for the load-carrying main laminate of a wind turbine rotor blade. The design process is split up into different key elements, each of which are presented...... and discussed separately. The key elements are all interconnected, which complicate the design process and involves an iterative procedure. The aim is to provide an overview of the process that governs the design of composite preforms for wind turbine blades. The survey can be used as an information source...... on composite preform manufacturing. Basic knowledge on wind turbine blade technology and composites is assumed. © 2013 Elsevier Ltd. All rights reserved....

  8. Mach number scaling of helicopter rotor blade/vortex interaction noise

    Science.gov (United States)

    Leighton, Kenneth P.; Harris, Wesley L.

    1985-01-01

    A parametric study of model helicopter rotor blade slap due to blade vortex interaction (BVI) was conducted in a 5 by 7.5-foot anechoic wind tunnel using model helicopter rotors with two, three, and four blades. The results were compared with a previously developed Mach number scaling theory. Three- and four-bladed rotor configurations were found to show very good agreement with the Mach number to the sixth power law for all conditions tested. A reduction of conditions for which BVI blade slap is detected was observed for three-bladed rotors when compared to the two-bladed baseline. The advance ratio boundaries of the four-bladed rotor exhibited an angular dependence not present for the two-bladed configuration. The upper limits for the advance ratio boundaries of the four-bladed rotors increased with increasing rotational speed.

  9. Novel controller design demonstration for vibration alleviation of helicopter rotor blades

    Science.gov (United States)

    Ulker, Fatma Demet; Nitzsche, Fred

    2012-04-01

    This paper presents an advanced controller design methodology for vibration alleviation of helicopter rotor sys- tems. Particularly, vibration alleviation in a forward ight regime where the rotor blades experience periodically varying aerodynamic loading was investigated. Controller synthesis was carried out under the time-periodic H2 and H∞ framework and the synthesis problem was solved based on both periodic Riccati and Linear Matrix Inequality (LMI) formulations. The closed-loop stability was analyzed using Floquet-Lyapunov theory, and the controller's performance was validated by closed-loop high-delity aeroelastic simulations. To validate the con- troller's performance an actively controlled trailing edge ap strategy was implemented. Computational cost was compared for both formulations.

  10. Fabrication of a Scaled MgB2 Racetrack Demonstrator Pole for a 10-MW Direct-Drive Wind Turbine Generator

    DEFF Research Database (Denmark)

    Magnusson, Niklas; Eliassen, Jan Christian; Abrahamsen, Asger Bech

    2018-01-01

    Field windings made of MgB2 wires or tapes are considered for their potential to reduce volume, weight, and cost of large offshore wind turbine generators. To gain experience of how to use this relatively new material in full-scale generators, tests of different winding methodologies and techniques...... are needed. In this paper, we describe in detail the steps used to wind a racetrack coil with a length of 1 m and a width of 0.5 m out of 4.5 km of MgB2 superconducting tape. The width corresponds to a full-scale pole of a 10-MW generator, whereas the length of the straight section is shorter than...... the corresponding full-scale pole. The coil was built up of ten double pancake coils. Each double pancake coil was wet wound using a semiautomatic winding process, where Stycast 2850 was applied directly to the MgB2 tape without any other dedicated electrical insulation. The strengths and weaknesses of the winding...

  11. Effects of Armature Winding Segmentation with Multiple Converters on the Short Circuit Torque of 10-MW Superconducting Wind Turbine Generators

    DEFF Research Database (Denmark)

    Liu, Dong; Polinder, Henk; Abrahamsen, Asger Bech

    2017-01-01

    Superconducting synchronous generators (SCSGs) are drawing more attention in large direct-drive wind turbine applications. Despite low weight and compactness, the short circuit torque of an SCSG may be too high for wind turbine constructions due to a large magnetic air gap of an SCSG. This paper...... aims at assessing the effects of armature winding segmentation on reducing the short circuit torque of 10-MW SCSGs. A concept of armature winding segmentation with multiple power electronic converters is presented. Four SCSG designs using different topologies are examined. Results show that armature...... winding segmentation effectively reduce the short circuit torque in all the four SCSG designs when one segment is shorted at the terminal....

  12. A Study of Active Rotor-Blade Vibration Control using Electro-Magnetic Actuation - Part II: Experiment

    DEFF Research Database (Denmark)

    Christensen, Rene Hardam; Santos, Ilmar

    2004-01-01

    . The remaining two sets of actuators are applied to act directly onto the hub, working as an active radial bearing controlling the rotor lateral movement. The rig is equipped with sensors measuring blade and rotor vibrations. Actuators and sensors are connected to a digital signal processor running the control......This is the second paper in a two-part study on active rotor-blade vibration control. This part presents an experimental contribution into the work of active controller design for rotor-blade systems. The primary aim is to give an experimental validation and show the applicability...... algorithm. Measurement signals and actuator control signals from the sensors and actuators fixed in the rotating disc are transmitted to the control unit through a slip-ring device. Various measured responses of both the controlled and the non-controlled system with identical blades and with deliberately...

  13. Condition monitoring of rotor blades of modern wind power systems; Ueberwachung mit Hertz. Condition Monitoring von Rotorblaettern moderner Windenergieanlagen

    Energy Technology Data Exchange (ETDEWEB)

    Fecht, Nikolaus

    2010-06-15

    With seven wind turbines, the Austrian wind farm ''Sternwald'' is the biggest wind farm in Upper Austria. It is the only wind farm in a forest, and all turbines are therefore equipped with automatic fire fighting equipment. The mountain range on which the wind farm is located is about 1000 m high, with strong wind and much ice and snow in the winter season. For this reason, the owner decided to instal a condition monitoring system with ice detectors. The piezoelectric sensors are mounted directly on the rotor blades as measurements on the nacelle will always be incorrect. Installation on the rotor blades, on the other hand, makes high demands on the fastenings and sensors as the velocity of the blade tips may be up to 250 km per hour. (orig.)

  14. Design of rotor blade for vertical axis wind turbine using double aerofoil

    Energy Technology Data Exchange (ETDEWEB)

    Chougule, P.D.; Ratkovich, N.; Kirkegaard, P.H.; Nielsen, Soeren R.K. [Aalborg Univ.. Dept. of Civil Engineering, Aalborg (Denmark)

    2012-07-01

    Nowadays, small vertical axis wind turbines are receiving more attention compared to horizontal wind turbines due to their suitability in urban use,because they generate less noise, have bird free turbines and lower cost. There are few vertical axis wind turbines design with good power curve. However, the efficiency of power extraction has not been improved. Therefore, an attempt has been made to utilize high lift technology in practice for vertical axis wind turbines in order to improve power efficiency. High lift is obtained by double aerofoil elements mainly used in aeroplane wing design. In this current work, two aerofoils are used to design a rotor blade for a vertical axis wind turbine to improve the power efficiency on the rotor. Double aerofoil blade design consists of a main aerofoil and a slat aerofoil. The parameters related to position and orientation of the slat aerofoil with respect to the main aerofoil defines the high lift. Orientation of slat aerofoil is a parameter of investigation in this paper. Computational fluid dynamics (CFD) have been used to obtain the aerodynamic characteristics of double aerofoil. The CFD simulations were carried out using Star CCM+ v7.04 (CD-adapco, UK) software. Aerofoils used in this work are selected from standard aerofoil shapes. (Author)

  15. Multidisciplinary Aerodynamic Design of a Rotor Blade for an Optimum Rotor Speed Helicopter

    Directory of Open Access Journals (Sweden)

    Jiayi Xie

    2017-06-01

    Full Text Available The aerodynamic design of rotor blades is challenging, and is crucial for the development of helicopter technology. Previous aerodynamic optimizations that focused only on limited design points find it difficult to balance flight performance across the entire flight envelope. This study develops a global optimum envelope (GOE method for determining blade parameters—blade twist, taper ratio, tip sweep—for optimum rotor speed helicopters (ORS-helicopters, balancing performance improvements in hover and various freestream velocities. The GOE method implements aerodynamic blade design by a bi-level optimization, composed of a global optimization step and a secondary optimization step. Power loss as a measure of rotor performance is chosen as the objective function, referred to as direct power loss (DPL in this study. A rotorcraft comprehensive code for trim simulation with a prescribed wake method is developed. With the application of the GOE method, a DPL reduction of as high as 16.7% can be achieved in hover, and 24% at high freestream velocity.

  16. Optimization of Root Section for Ultra-long Steam Turbine Rotor Blade

    Science.gov (United States)

    Hála, Jindřich; Luxa, Martin; Šimurda, David; Bobčík, Marek; Novák, Ondřej; Rudas, Bartoloměj; Synáč, Jaroslav

    2018-04-01

    This study presents the comparison of aerodynamic performances of two successive designs of the root profiles for the ultra-long rotor blade equipped with a straight fir-tree dovetail. Since aerodynamic and strength requirements laid upon the root section design are contradictory, it is necessary to aerodynamically optimize the design within the limits given by the foremost strength requirements. The most limiting criterion of the static strength is the size of the blade cross-section, which is determined by the number of blades in a rotor and also by the shape and size of a blade dovetail. The aerodynamic design requires mainly the zero incidence angle at the inlet of a profile and in the ideal case ensures that the load does not exceed a limit load condition. Moreover, the typical root profile cascades are transonic with supersonic exit Mach number, therefore, the shape of a suction side and a trailing edge has to respect transonic expansion of a working gas. In this paper, the two variants of root section profile cascades are compared and the aerodynamic qualities of both variants are verified using CFD simulation and two mutually independent experimental methods of measurements (optical and pneumatic).

  17. Helicopter Rotor Blade Computation in Unsteady Flows Using Moving Overset Grids

    Science.gov (United States)

    Ahmad, Jasim; Duque, Earl P. N.

    1996-01-01

    An overset grid thin-layer Navier-Stokes code has been extended to include dynamic motion of helicopter rotor blades through relative grid motion. The unsteady flowfield and airloads on an AH-IG rotor in forward flight were computed to verify the methodology and to demonstrate the method's potential usefulness towards comprehensive helicopter codes. In addition, the method uses the blade's first harmonics measured in the flight test to prescribe the blade motion. The solution was impulsively started and became periodic in less than three rotor revolutions. Detailed unsteady numerical flow visualization techniques were applied to the entire unsteady data set of five rotor revolutions and exhibited flowfield features such as blade vortex interaction and wake roll-up. The unsteady blade loads and surface pressures compare well against those from flight measurements. Details of the method, a discussion of the resulting predicted flowfield, and requirements for future work are presented. Overall, given the proper blade dynamics, this method can compute the unsteady flowfield of a general helicopter rotor in forward flight.

  18. Air and ground resonance of helicopters with elastically tailored composite rotor blades

    Science.gov (United States)

    Smith, Edward C.; Chopra, Inderjit

    1993-01-01

    The aeromechanical stability, including air resonance in hover, air resonance in forward flight, and ground resonance, of a helicopter with elastically tailored composite rotor blades is investigated. Five soft-inplane hingeless rotor configurations, featuring elastic pitch-lag, pitch-flap and extension-torsion couplings, are analyzed. Elastic couplings introduced through tailored composite blade spars can have a powerful effect on both air and ground resonance behavior. Elastic pitch-flap couplings (positive and negative) strongly affect body, rotor and dynamic inflow modes. Air resonance stability is diminished by elastic pitch-flap couplings in hover and forwrad flight. Negative pitch-lag elastic coupling has a stabilizing effect on the regressive lag mode in hover and forward flight. The negative pitch-lag coupling has a detrimental effect on ground resonance stability. Extension-torsion elastic coupling (blade pitch decreases due to tension) decreases regressive lag mode stability in both airborne and ground contact conditions. Increasing thrust levels has a beneficial influence on ground resonance stability for rotors with pitch-flap and extension-torsion coupling and is only marginally effective in improving stability of rotors with pitch-lag coupling.

  19. Performance characterization of active fiber-composite actuators for helicopter rotor blade applications

    Science.gov (United States)

    Wickramasinghe, Viresh K.; Hagood, Nesbitt W.

    2002-07-01

    The primary objective of this work was to characterize the performance of the Active Fiber Composite (AFC) actuator material system for the Boeing Active Material Rotor (AMR) blade application. The AFCs were a new structural actuator system consisting of piezoceramic fibers embedded in an epoxy matrix and sandwiched between interdigitated electrodes to orient the driving electric field in the fiber direction to use the primary piezoelectric effect. These actuators were integrated directly into the blade spar laminate as active plies within the composite structure to perform structural actuation for vibration control in helicopters. Therefore, it was necessary to conduct extensive electromechanical material characterization to evaluate AFCs both as actuators and as structural components of the rotor blade. The characterization tests designed to extract important electromechanical properties under simulated blade operating conditions included stress-strain tests, free strain tests and actuation under tensile load tests. This paper presents the test results as well as the comprehensive testing process developed to evaluate the relevant AFC material properties. The results from this comprehensive performance characterization of the AFC material system supported the design and operation of the Boeing AMR blade scheduled for hover and forward flight wind tunnel tests.

  20. Aeromechanical stability of helicopters with composite rotor blades in forward flight

    Science.gov (United States)

    Smith, Edward C.; Chopra, Inderjit

    1992-01-01

    The aeromechanical stability, including air resonance in hover, air resonance in forward flight, and ground resonance, of a helicopter with elastically tailored composite rotor blades is investigated. Five soft-inplane hingeless rotor configurations, featuring elastic pitch-lag, pitch-flap and extension-torsion couplings, are analyzed. Elastic couplings introduced through tailored composite blade spars can have a powerful effect on both air and ground resonance behavior. Elastic pitch-flap couplings (positive and negative) strongly affect body, rotor and dynamic inflow modes. Air resonance stability is diminished by elastic pitch-flap couplings in hover and forward flight. Negative pitch-lag elastic coupling has a stabilizing effect on the regressive lag mode in hover and forward flight. The negative pitch-lag coupling has a detrimental effect on ground resonance stability. Extension-torsion elastic coupling (blade pitch decreases due to tension) decreases regressive lag mode stability in both airborne and ground contact conditions. Increasing thrust levels has a beneficial influence on ground resonance stability for rotors with pitch-flap and extension-torsion coupling and is only marginally effective in improving stability of rotors with pitch-lag coupling.

  1. Optimization of rotor blades for combined structural, dynamic, and aerodynamic properties

    Science.gov (United States)

    He, Cheng-Jian; Peters, David A.

    1990-01-01

    Optimal helicopter blade design with computer-based mathematical programming has received more and more attention in recent years. Most of the research has focused on optimum dynamic characteristics of rotor blades to reduce vehicle vibration. There is also work on optimization of aerodynamic performance and on composite structural design. This research has greatly increased our understanding of helicopter optimum design in each of these aspects. Helicopter design is an inherently multidisciplinary process involving strong interactions among various disciplines which can appropriately include aerodynamics; dynamics, both flight dynamics and structural dynamics; aeroelasticity: vibrations and stability; and even acoustics. Therefore, the helicopter design process must satisfy manifold requirements related to the aforementioned diverse disciplines. In our present work, we attempt to combine several of these important effects in a unified manner. First, we design a blade with optimum aerodynamic performance by proper layout of blade planform and spanwise twist. Second, the blade is designed to have natural frequencies that are placed away from integer multiples of the rotor speed for a good dynamic characteristics. Third, the structure is made as light as possible with sufficient rotational inertia to allow for autorotational landing, with safe stress margins and flight fatigue life at each cross-section, and with aeroelastical stability and low vibrations. Finally, a unified optimization refines the solution.

  2. Helicopter rotor blade frequency evolution with damage growth and signal processing

    Science.gov (United States)

    Roy, Niranjan; Ganguli, Ranjan

    2005-05-01

    Structural damage in materials evolves over time due to growth of fatigue cracks in homogenous materials and a complicated process of matrix cracking, delamination, fiber breakage and fiber matrix debonding in composite materials. In this study, a finite element model of the helicopter rotor blade is used to analyze the effect of damage growth on the modal frequencies in a qualitative manner. Phenomenological models of material degradation for homogenous and composite materials are used. Results show that damage can be detected by monitoring changes in lower as well as higher mode flap (out-of-plane bending), lag (in-plane bending) and torsion rotating frequencies, especially for composite materials where the onset of the last stage of damage of fiber breakage is most critical. Curve fits are also proposed for mathematical modeling of the relationship between rotating frequencies and cycles. Finally, since operational data are noisy and also contaminated with outliers, denoising algorithms based on recursive median filters and radial basis function neural networks and wavelets are studied and compared with a moving average filter using simulated data for improved health-monitoring application. A novel recursive median filter is designed using integer programming through genetic algorithm and is found to have comparable performance to neural networks with much less complexity and is better than wavelet denoising for outlier removal. This filter is proposed as a tool for denoising time series of damage indicators.

  3. A preliminary investigation of finite-element modeling for composite rotor blades

    Science.gov (United States)

    Lake, Renee C.; Nixon, Mark W.

    1988-01-01

    The results from an initial phase of an in-house study aimed at improving the dynamic and aerodynamic characteristics of composite rotor blades through the use of elastic couplings are presented. Large degree of freedom shell finite element models of an extension twist coupled composite tube were developed and analyzed using MSC/NASTRAN. An analysis employing a simplified beam finite element representation of the specimen with the equivalent engineering stiffness was additionally performed. Results from the shell finite element normal modes and frequency analysis were compared to those obtained experimentally, showing an agreement within 13 percent. There was appreciable degradation in the frequency prediction for the torsional mode, which is elastically coupled. This was due to the absence of off-diagonal coupling terms in the formulation of the equivalent engineering stiffness. Parametric studies of frequency variation due to small changes in ply orientation angle and ply thickness were also performed. Results showed linear frequency variations less than 2 percent per 1 degree variation in the ply orientation angle, and 1 percent per 0.0001 inch variation in the ply thickness.

  4. Flow performance of highly loaded axial fan with bowed rotor blades

    International Nuclear Information System (INIS)

    Chen, L; Liu, X J; Yang, A L; Dai, R

    2013-01-01

    In this paper, a partial bowed rotor blade was proposed for a newly designed high loaded axial fan. The blade was positively bowed 30 degrees from hub to 30 percent spanwise position. Flows of radial blade and bowed blade fans were numerically compared for various operation conditions. Results show that the fan's performance is improved. At the designed condition with flow coefficient of 0.52, the efficiency of the bowed blade fan is increased 1.44% and the static pressure rise is increased 11%. Comparing the flow structures, it can be found that the separated flow in the bowed fan is reduced and confined within 20 percent span, which is less than the 35 percent in the radial fan. It means that the bowed blade generates negative blade force and counteracts partial centrifugal force. It is alleviates the radial movements of boundary layers in fan's hub region. Flow losses due to 3D mixing are reduced in the rotor. Inlet flow to downstream stator is also improved

  5. Flow performance of highly loaded axial fan with bowed rotor blades

    Science.gov (United States)

    Chen, L.; Liu, X. J.; Yang, A. L.; Dai, R.

    2013-12-01

    In this paper, a partial bowed rotor blade was proposed for a newly designed high loaded axial fan. The blade was positively bowed 30 degrees from hub to 30 percent spanwise position. Flows of radial blade and bowed blade fans were numerically compared for various operation conditions. Results show that the fan's performance is improved. At the designed condition with flow coefficient of 0.52, the efficiency of the bowed blade fan is increased 1.44% and the static pressure rise is increased 11%. Comparing the flow structures, it can be found that the separated flow in the bowed fan is reduced and confined within 20 percent span, which is less than the 35 percent in the radial fan. It means that the bowed blade generates negative blade force and counteracts partial centrifugal force. It is alleviates the radial movements of boundary layers in fan's hub region. Flow losses due to 3D mixing are reduced in the rotor. Inlet flow to downstream stator is also improved.

  6. Evaluation of wind potential for an optimum choice of wind turbine generator on the sites of Lomé, Accra, and Cotonou located in the gulf of Guinea

    Directory of Open Access Journals (Sweden)

    Akim Adekunlé SALAMI

    2016-11-01

    Full Text Available This work presents the characterization and assessment of wind energy potential in annual and monthly levels of the sites of Lomé, Accra and Cotonou located in the Gulf of Guinea, and the optimal characteristics of wind turbines to be installed on these sites. Studies of characterization and the wind potential of these sites from the wind speed data collected over a period of thirteen years at a height of 10 meters above the ground, show an annual average speed of 3.52 m/s for Lomé, 3.99 m/s for Cotonou and 4.16 m/s for Accra. These studies also showed that a monthly average speed exceeding 4 m/s was observed on the sites of Cotonou and Accra during the months of February, March, April, July, August and September and during the months of July, August and September on the site of Lomé. After a series of simulation conducted using the software named PotEol that we have developed in Scilab, we have retained that the wind turbines rated speeds of ~8 to 9 m/s at the sites of Lomé and Cotonou and ~ 9 to 10 m/s on the site of Accra would be the most appropriate speeds for optimal exploitation of electric energy from wind farms at a height of 50 m above the ground. Article History: Received May 26th 2016; Received in revised form August 24th 2016; Accepted August 30th 2016; Available online How to Cite This Article: Salami, A.A., Ajavon, A.S.A , Kodjo, M.K. and Bédja, K. (2016 Evaluation of Wind Potential for an Optimum Choice of Wind Turbine Generator on the Sites of Lomé, Accra, and Cotonou Located in the Gulf of Guinea. Int. Journal of Renewable Energy Development, 5(3, 211-223. http://dx.doi.org/10.14710/ijred.5.3.211-223

  7. Unified continuum damage model for matrix cracking in composite rotor blades

    Energy Technology Data Exchange (ETDEWEB)

    Pollayi, Hemaraju; Harursampath, Dineshkumar [Nonlinear Multifunctional Composites - Analysis and Design Lab (NMCAD Lab) Department of Aerospace Engineering Indian Institute of Science Bangalore - 560012, Karnataka (India)

    2015-03-10

    This paper deals with modeling of the first damage mode, matrix micro-cracking, in helicopter rotor/wind turbine blades and how this effects the overall cross-sectional stiffness. The helicopter/wind turbine rotor system operates in a highly dynamic and unsteady environment leading to severe vibratory loads present in the system. Repeated exposure to this loading condition can induce damage in the composite rotor blades. These rotor/turbine blades are generally made of fiber-reinforced laminated composites and exhibit various competing modes of damage such as matrix micro-cracking, delamination, and fiber breakage. There is a need to study the behavior of the composite rotor system under various key damage modes in composite materials for developing Structural Health Monitoring (SHM) system. Each blade is modeled as a beam based on geometrically non-linear 3-D elasticity theory. Each blade thus splits into 2-D analyzes of cross-sections and non-linear 1-D analyzes along the beam reference curves. Two different tools are used here for complete 3-D analysis: VABS for 2-D cross-sectional analysis and GEBT for 1-D beam analysis. The physically-based failure models for matrix in compression and tension loading are used in the present work. Matrix cracking is detected using two failure criterion: Matrix Failure in Compression and Matrix Failure in Tension which are based on the recovered field. A strain variable is set which drives the damage variable for matrix cracking and this damage variable is used to estimate the reduced cross-sectional stiffness. The matrix micro-cracking is performed in two different approaches: (i) Element-wise, and (ii) Node-wise. The procedure presented in this paper is implemented in VABS as matrix micro-cracking modeling module. Three examples are presented to investigate the matrix failure model which illustrate the effect of matrix cracking on cross-sectional stiffness by varying the applied cyclic load.

  8. NDT detection and quantification of induced defects on composite helicopter rotor blade and UAV wing sections

    Science.gov (United States)

    Findeis, Dirk; Gryzagoridis, Jasson; Musonda, Vincent

    2008-09-01

    Digital Shearography and Infrared Thermography (IRT) techniques were employed to test non-destructively samples from aircraft structures of composite material nature. Background information on the techniques is presented and it is noted that much of the inspection work reviewed in the literature has focused on qualitative evaluation of the defects rather than quantitative. There is however, need to quantify the defects if the threshold rejection criterion of whether the component inspected is fit for service has to be established. In this paper an attempt to quantify induced defects on a helicopter main rotor blade and Unmanned Aerospace Vehicle (UAV) composite material is presented. The fringe patterns exhibited by Digital Shearography were used to quantify the defects by relating the number of fringes created to the depth of the defect or flaw. Qualitative evaluation of defects with IRT was achieved through a hot spot temperature indication above the flaw on the surface of the material. The results of the work indicate that the Shearographic technique proved to be more sensitive than the IRT technique. It should be mentioned that there is "no set standard procedure" tailored for testing of composites. Each composite material tested is more likely to respond differently to defect detection and this depends generally on the component geometry and a suitable selection of the loading system to suit a particular test. The experimental procedure that is reported in this paper can be used as a basis for designing a testing or calibration procedure for defects detection on any particular composite material component or structure.

  9. Unified continuum damage model for matrix cracking in composite rotor blades

    International Nuclear Information System (INIS)

    Pollayi, Hemaraju; Harursampath, Dineshkumar

    2015-01-01

    This paper deals with modeling of the first damage mode, matrix micro-cracking, in helicopter rotor/wind turbine blades and how this effects the overall cross-sectional stiffness. The helicopter/wind turbine rotor system operates in a highly dynamic and unsteady environment leading to severe vibratory loads present in the system. Repeated exposure to this loading condition can induce damage in the composite rotor blades. These rotor/turbine blades are generally made of fiber-reinforced laminated composites and exhibit various competing modes of damage such as matrix micro-cracking, delamination, and fiber breakage. There is a need to study the behavior of the composite rotor system under various key damage modes in composite materials for developing Structural Health Monitoring (SHM) system. Each blade is modeled as a beam based on geometrically non-linear 3-D elasticity theory. Each blade thus splits into 2-D analyzes of cross-sections and non-linear 1-D analyzes along the beam reference curves. Two different tools are used here for complete 3-D analysis: VABS for 2-D cross-sectional analysis and GEBT for 1-D beam analysis. The physically-based failure models for matrix in compression and tension loading are used in the present work. Matrix cracking is detected using two failure criterion: Matrix Failure in Compression and Matrix Failure in Tension which are based on the recovered field. A strain variable is set which drives the damage variable for matrix cracking and this damage variable is used to estimate the reduced cross-sectional stiffness. The matrix micro-cracking is performed in two different approaches: (i) Element-wise, and (ii) Node-wise. The procedure presented in this paper is implemented in VABS as matrix micro-cracking modeling module. Three examples are presented to investigate the matrix failure model which illustrate the effect of matrix cracking on cross-sectional stiffness by varying the applied cyclic load

  10. Extension-torsion coupling behavior of advanced composite tilt-rotor blades

    Science.gov (United States)

    Kosmatka, J. B.

    1989-01-01

    An analytic model was developed to study the extension-bend-twist coupling behavior of an advanced composite helicopter or tilt-rotor blade. The outer surface of the blade is defined by rotating an arbitrary cross section about an initial twist axis. The cross section can be nonhomogeneous and composed of generally anisotropic materials. The model is developed based upon a three dimensional elasticity approach that is recast as a coupled two-dimensional boundary value problem defined in a curvilinear coordinate system. Displacement solutions are written in terms of known functions that represent extension, bending, and twisting and unknown functions for local cross section deformations. The unknown local deformation functions are determined by applying the principle of minimum potential energy to the discretized two-dimensional cross section. This is an application of the Ritz method, where the trial function family is the displacement field associated with a finite element (8-node isoparametric quadrilaterals) representation of the section. A computer program was written where the cross section is discretized into 8-node quadrilateral subregions. Initially the program was verified using previously published results (both three-dimensional elasticity and technical beam theory) for pretwisted isotropic bars with an elliptical cross section. In addition, solid and thin-wall multi-cell NACA-0012 airfoil sections were analyzed to illustrate the pronounced effects that pretwist, initial twist axis location, and spar location has on coupled behavior. Currently, a series of advanced composite airfoils are being modeled in order to assess how the use of laminated composite materials interacts with pretwist to alter the coupling behavior of the blade. These studies will investigate the use of different ply angle orientations and the use of symmetric versus unsymmetric laminates.

  11. System Impact Study of the Eastern Grid of Sumba Island, Indonesia: Steady-State and Dynamic System Modeling for the Integration of One and Two 850-kW Wind Turbine Generators

    Energy Technology Data Exchange (ETDEWEB)

    Oswal, R. [Innovation Wind Energy, Inc., Jacksonville, FL (United States); Jain, P. [Innovation Wind Energy, Inc., Jacksonville, FL (United States); Muljadi, Eduard [National Renewable Energy Lab. (NREL), Golden, CO (United States); Hirsch, Brian [National Renewable Energy Lab. (NREL), Golden, CO (United States); Castermans, B. [Winrock International Inc., Little Rock, AR (United States); Chandra, J. [Winrock International Inc., Little Rock, AR (United States); Raharjo, S. [Winrock International Inc., Little Rock, AR (United States); Hardison, R. [Winrock International Inc., Little Rock, AR (United States)

    2016-01-01

    The goal of this project was to study the impact of integrating one and two 850-kW wind turbine generators into the eastern power system network of Sumba Island, Indonesia. A model was created for the 20-kV distribution network as it existed in the first quarter of 2015 with a peak load of 5.682 MW. Detailed data were collected for each element of the network. Load flow, short-circuit, and transient analyses were performed using DIgSILENT PowerFactory 15.2.1.

  12. Inspection of helicopter rotor blades with the help of guided waves and "turning modes": Experimental and finite element analysis

    Science.gov (United States)

    Barnard, Daniel; Chakrapani, Sunil Kishore; Dayal, Vinay

    2013-01-01

    Modern helicopter rotor blades constructed of composite materials offer significant inspection challenges, particularly at inner structures, where geometry and differing material properties and anisotropy make placement of the probing energy difficult. This paper presents an application of Lamb waves to these structures, where mode conversion occurs at internal geometric discontinuities. These additional modes were found to successfully propagate to the targeted regions inside the rotor and back out, allowing evaluation of the structure. A finite element model was developed to simulate wave propagation and mode conversion in the structure and aid in identifying the signals received in the laboratory experiment. A good correlation between numerical and experimental results was observed.

  13. able utilizando redes neuronales artificiales; UTILIZATION OF ARTIFICIAL NEURAL NETWORK IN THE SIMULATION AND CONTROL OF WIND TURBINE GENERATORS WITH VARIABLE SPEED AND VARIABLE PITCH.

    Directory of Open Access Journals (Sweden)

    Osley López González

    2011-02-01

    , considered as a whole, must be able of respond with anadequate precision and speed in response to the randomness and variability of the wind.The relationship between the wind speed, the blade pitch and the generator speed in order to produce themaximum power and also be able to limit the output power for large wind speeds is a very complicated oneand it is very difficult to find its mathematical function.In this paper, the authors, utilizing the MATLABSIMULINK toolboxes, propose representing this functional relation by means of an Artificial Neural Network(ANN. The parameters and characteristics of an existing wind turbine generator are utilized and it isdemonstrated that it is possible to use an ANN in the simulation and control of a variable speed, variablepitch wind turbine that capture the maximum power from the wind.

  14. 3D Warping Actuation Driven Dynamic Camber Control Concept for Helicopter Rotor Blades, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — In a rotorcraft, optimized camber change not only reduces vibratory hub loads and noise but also increases available thrust and improved flight control augmentation....

  15. Optimizing parameters of GTU cycle and design values of air-gas channel in a gas turbine with cooled nozzle and rotor blades

    Science.gov (United States)

    Kler, A. M.; Zakharov, Yu. B.

    2012-09-01

    The authors have formulated the problem of joint optimization of pressure and temperature of combustion products before gas turbine, profiles of nozzle and rotor blades of gas turbine, and cooling air flow rates through nozzle and rotor blades. The article offers an original approach to optimization of profiles of gas turbine blades where the optimized profiles are presented as linear combinations of preliminarily formed basic profiles. The given examples relate to optimization of the gas turbine unit on the criterion of power efficiency at preliminary heat removal from air flows supplied for the air-gas channel cooling and without such removal.

  16. A New Higher-Order Composite Theory for Analysis and Design of High Speed Tilt-Rotor Blades

    Science.gov (United States)

    McCarthy, Thomas Robert

    1996-01-01

    A higher-order theory is developed to model composite box beams with arbitrary wall thicknesses. The theory, based on a refined displacement field, represents a three-dimensional model which approximates the elasticity solution. Therefore, the cross-sectional properties are not reduced to one-dimensional beam parameters. Both inplane and out-of-plane warping are automatically included in the formulation. The model accurately captures the transverse shear stresses through the thickness of each wall while satisfying all stress-free boundary conditions. Several numerical results are presented to validate the present theory. The developed theory is then used to model the load carrying member of a tilt-rotor blade which has thick-walled sections. The composite structural analysis is coupled with an aerodynamic analysis to compute the aeroelastic stability of the blade. Finally, a multidisciplinary optimization procedure is developed to improve the aerodynamic, structural and aeroelastic performance of the tilt-rotor aircraft. The Kreisselmeier-Steinhauser function is used to formulate the multiobjective function problem and a hybrid approximate analysis is used to reduce the computational effort. The optimum results are compared with the baseline values and show significant improvements in the overall performance of the tilt-rotor blade.

  17. Effects of Mie tip-vane on pressure distribution of rotor blade and power augmentation of horizontal axis wind turbine; Yokutan shoyoku Mie ben ni yoru suiheijiku fusha yokumenjo no atsuryoku bunpu no kaizen to seino kojo tono kankei

    Energy Technology Data Exchange (ETDEWEB)

    Shimizu, Y.; Maeda, T.; Kamada, Y. [Mie Univ., Mie (Japan); Seto, H. [Mitsubishi Motors Corp., Tokyo (Japan)

    2000-04-01

    By recent developments of exclusive rotor blade, the efficiency of wind turbine is improved substantially. By measuring pressure on rotor blades of horizontal axis wind turbines rotating in wind tunnels, this report clarified relation between improvement of pressure distribution on main rotor blades by Mie vane and upgrade of wind turbine performance. The results under mentioned have been got by measuring pressure distribution on rotor blades, visualization by tuft, and measuring resistance of Mie vane. (1) The difference of pressure between suction surface and pressure surface on the end of rotor blade increase, and output power of wind turbine improves. (2) Vortex of blade end is inhibited by Mie vane. (3) The reason of reduction on wind turbine performance with Mie vane in aria of high rotating speed ratio is the increase of Mie vane flow resistance.(NEDO)

  18. A Critical Evaluation of Structural Analysis Tools used for the Design of Large Composite Wind Turbine Rotor Blades under Ultimate and Cycle Loading

    DEFF Research Database (Denmark)

    Lekou, D.J.; Bacharoudis, K. C.; Farinas, A. B.

    2015-01-01

    Rotor blades for 10-20MW wind turbines may exceed 120m. To meet the demanding requirements of the blade design, structural analysis tools have been developed individually and combined with commercial available ones by blade designers. Due to the various available codes, understanding and estimating...

  19. Influencia del movimiento tridimensional sobre los engranajes planetarios tipo 2KH-A en aerogeneradores. // Influence of tridimensional movement in planetary gears type 2KH-A used in gearboxes for wind turbine generator systems.

    Directory of Open Access Journals (Sweden)

    J. Wellesley-Bourke Funcasta

    2007-09-01

    Full Text Available En el trabajo se desarrolla el basamento matemático para establecer el análisis del efecto nocivo que se produce sobre losrodamientos de los mecanismos planetarios empleados en los aerogeneradores, dado esto por las condiciones variables delviento en cuanto a su velocidad y dirección.Palabras claves: Efecto giroscópico, engranajes planetarios, cargas dinámicas, energía eólica.______________________________________________________________________________AbstractIn this paper is presented the mathematical base useful to establish the analysis that deals with the noxious effect producedon the planetary mechanisms in the gearboxes for wind turbine generator systems, given by the variable conditions of thevelocity and direction of the wind.Key words: Gyroscopic effect, planetary gears, dynamic loads, wind turbine, wind energy.

  20. Parameter analysis and optimal design for low-speed permanent magnet wind turbine generators%低速永磁风力发电机的参数分析及优化设计

    Institute of Scientific and Technical Information of China (English)

    何庆领; 王群京

    2011-01-01

    文章讨论了低速永磁同步风力发电机的设计特点,为了有效地减少阻力矩,采用分数槽绕组,为减少漏磁通,采用瓦片型和放射状的永磁体安装结构,并重点对结构参数与运行性能之间的内在关系进行了参数分析,为风力发电机本体的优化设计打下基础.在一定安装尺寸的限制下,以电机效率作为优化目标,采用基于混沌理论的最优化算法获取风力发电机的最大输出效率.%This paper discusses the design characteristics of low-speed permanent magnet synchronous wind turbine generator, including the use of fractional slot windings to effectively reduce the resistance moment, the use of tiles and reflective-like structure to reduce leakage flux,and the installation of permanent magnet The intrinsic relationship between structural parameters and operational performance is also analyzed for the optimal design of wind turbine foundation. Aiming at optimizing the motor efficiency, the optimization algorithm based on chaos theory can be used to obtain the maximum output efficiency of wind turbine generator under a certain restriction of installation size.

  1. Anti-freeze coatings for the rotor blades of wind turbines; Anti-freeze Beschichtungen fuer Rotorblaetter von Windenergieanlagen

    Energy Technology Data Exchange (ETDEWEB)

    Siegmann, K.; Kaufmann, A.; Hirayama, M.

    2006-07-01

    This final report for the Swiss Federal Office of Energy (SFOE) takes a look at projects involving the development of suggestions for coatings for the rotor blades of wind turbines. The coatings are to reduce the formation of hoarfrost on the leading edges of the blades. Various coatings are described and the mechanisms involved in the formation of the frost and in keeping the blades as free as possible from frost are discussed. Global know-how on the subject is discussed, as is know-how available in Europe and Switzerland. Manufacturers, planning offices and installation operators are listed, as are research institutes who are dealing with this problem. In the summary, the authors stress the importance of choosing the coating most suitable for the actual climatic conditions at the wind turbine's location. A suggestion is made for further work in this area.

  2. Comparison of composite rotor blade models: A coupled-beam analysis and an MSC/NASTRAN finite-element model

    Science.gov (United States)

    Hodges, Robert V.; Nixon, Mark W.; Rehfield, Lawrence W.

    1987-01-01

    A methodology was developed for the structural analysis of composite rotor blades. This coupled-beam analysis is relatively simple to use compared with alternative analysis techniques. The beam analysis was developed for thin-wall single-cell rotor structures and includes the effects of elastic coupling. This paper demonstrates the effectiveness of the new composite-beam analysis method through comparison of its results with those of an established baseline analysis technique. The baseline analysis is an MSC/NASTRAN finite-element model built up from anisotropic shell elements. Deformations are compared for three linear static load cases of centrifugal force at design rotor speed, applied torque, and lift for an ideal rotor in hover. A D-spar designed to twist under axial loading is the subject of the analysis. Results indicate the coupled-beam analysis is well within engineering accuracy.

  3. Development of a structural optimization capability for the aeroelastic tailoring of composite rotor blades with straight and swept tips

    Science.gov (United States)

    Friedmann, P. P.; Venkatesan, C.; Yuan, K.

    1992-01-01

    This paper describes the development of a new structural optimization capability aimed at the aeroelastic tailoring of composite rotor blades with straight and swept tips. The primary objective is to reduce vibration levels in forward flight without diminishing the aeroelastic stability margins of the blade. In the course of this research activity a number of complicated tasks have been addressed: (1) development of a new, aeroelastic stability and response analysis; (2) formulation of a new comprehensive sensitive analysis, which facilitates the generation of the appropriate approximations for the objective and the constraints; (3) physical understanding of the new model and, in particular, determination of its potential for aeroelastic tailoring, and (4) combination of the newly developed analysis capability, the sensitivity derivatives and the optimizer into a comprehensive optimization capability. The first three tasks have been completed and the fourth task is in progress.

  4. Assessment of Lightning Transients on a De-Iced Rotor Blade with Predictive Tools and Coaxial Return Measurements

    Science.gov (United States)

    Guillet, S.; Gosmain, A.; Ducoux, W.; Ponçon, M.; Fontaine, G.; Desseix, P.; Perraud, P.

    2012-05-01

    The increasing use of composite materials in aircrafts primary structures has led to different problematics in the field of safety of flight in lightning conditions. The consequences of this technological mutation, which occurs in a parallel context of extension of electrified critical functions, are addressed by aircraft manufacturers through the enhancement of their available assessment means of lightning transient. On the one hand, simulation tools, provided an accurate description of aircraft design, are today valuable assessment tools, in both predictive and operative terms. On the other hand, in-house test means allow confirmation and consolidation of design office hardening solutions. The combined use of predictive simulation tools and in- house test means offers an efficient and reliable support for all aircraft developments in their various life-time stages. The present paper provides PREFACE research project results that illustrate the above introduced strategy on the de-icing system of the NH90 composite main rotor blade.

  5. Vibration crack corrosion behavior and failure mechanisms of highly alloyed duplex steels in steam turbine rotor blades

    International Nuclear Information System (INIS)

    Wunderlich, R.

    1991-01-01

    The aim was to test the new duplex steel X3CrMnNiMoN 25 6 4 (A905) for its suitability as a steam turbine rotor blade material. Due to the increased proportion of manganese and nitrogen, compared to A903, in this duplex steel in the solution annealed state, an elastic limit of about 600 N/mm 2 acceptable for steam turbine rotor blades was reached. A micro-duplex structure (recrystallized secondary structure) consisting of 50% each of ferrite and Austenite proved to be the optimum structure composition. To measure the SwRK behaviour, Woehler curves were produced in media containing corrosive NaCl. The mean stress was 250 N/mm 2 , partly 350 N/mm 2 . The maximum duration of the test was given as 3 x 10 7 load cycles at a frequency of 50 Hz. The experimental time was partly extended to 5 x 10 7 load cycles. In order to guarantee as realistic a test as possible, the Sw RK tests took place in aqueous NaCl solution saturated with air. To correspond to envorinmental conditions in actual operation, the electrolyte temperature was varied between 80deg and 150deg C, the Na Cl concentration of the solution was varied between very dilute (0.01 M) and nearly saturated (22%) and the pH value was varied between pH 8 and pH 3. Accompanying passive oxide layer investigations should give information on the thickness and morphology of the layers formed. (orig./MM) [de

  6. Calibration of partial safety factors for wind turbine rotor blades against fatigue failure; Kalibrering af partielle sikkerhedsfaktorer for udmattelse af vindmoellerotorer

    Energy Technology Data Exchange (ETDEWEB)

    Christensen, C.J.; Ronold, K.O.; Thoegersen, M.L.

    2000-08-01

    The report describes a calibration of partial safety factors for wind turbine rotor blades subjected to fatigue loading in flapwise and edgewise bending. While earlier models - developed by the authors - dealt with such calibrations for site-specific individual turbines only, the calibration model applied herein covers an integrated analysis with different turbines on different sites and with different blade materials. The result is an optimized set of partial safety factors, i.e. a set of safety factors that lead to minimum deviation from the target reliability of the achieved reliabilities over the selected scope of turbines, sites and materials. The turbines included in the study cover rated powers of 450-600 kW. The result from the calibration are discussed in relation to the partial safety factors that are given in the Danish codes for design of glass fibre reinforced rotor blades (DS472 and DS456). (au)

  7. Investigation of Blade-row Flow Distributions in Axial-flow-compressor Stage Consisting of Guide Vanes and Rotor-blade Row

    Science.gov (United States)

    Mahoney, John J; Dugan, Paul D; Budinger, Raymond E; Goelzer, H Fred

    1950-01-01

    A 30-inch tip-diameter axial-flow compressor stage was investigated with and without rotor to determine individual blade-row performance, interblade-row effects, and outer-wall boundary-layer conditions. Velocity gradients at guide-vane outlet without rotor approximated design assumptions, when the measured variation of leaving angle was considered. With rotor in operation, Mach number and rotor-blade effects changed flow distribution leaving guide vanes and invalidated design assumption of radial equilibrium. Rotor-blade performance correlated interpolated two-dimensional results within 2 degrees, although tip stall was indicated in experimental and not two-dimensional results. Boundary-displacement thickness was less than 1.0 and 1.5 percent of passage height after guide vanes and after rotor, respectively, but increased rapidly after rotor when tip stall occurred.

  8. Intelligent production of rotor blades using IT-aided automation approaches; Intelligente Fertigung von Rotorblaettern durch IT-gestuetzte Automationsansaetze

    Energy Technology Data Exchange (ETDEWEB)

    Ohlendorf, J.H.; Thoben, K.D. [Bremen Univ. (Germany). BIK Institut fuer integrierte Produktentwicklung; Hans, C.; Ghrairi, Z. [Bremer Institut fuer Produktion und Logistik GmbH, Bremen (Germany)

    2010-08-15

    In this paper, the necessity of a control system for resin infusion and curing was elaborated with the example of rotor blade manufacturing. Also, an innovative multi-component learning control system that is based on the results of the iReMo-project was introduced. It reveals so-far hidden processes within the moulding tools via a sophisticated sensor-network, meets all imposed requirements and will therewith considerably change and improve the moulding process of reinforced polymer composite materials. In an environment that has little contact with the automation technology today, these innovations already bear a great potential to increase efficiency and quality and reduce costs and lead times. Further benefits will result from the interconnection with other automation solutions for fibre-reinforced composites products, i.e., the automatic placement of fabrics in the mould and will be subject to future research activities. An emphasis will be put on the continuous data management to assure quality and traceability. A consequent gathering and filing of all product data in terms of a Product Lifecyle Management (PLM) would be also possible for fibre-reinforced composites. (orig.)

  9. Effect of operating methods of wind turbine-generator system on net power extraction under wind speed fluctuations in fields; Hendo fukyoka deno doryoku chushutsu kara mita furyoku hatsuden system no unten seigyoho ni kansuru kosatsu

    Energy Technology Data Exchange (ETDEWEB)

    Wakui, T. [Japan Society for the Promotion of Science, Tokyo (Japan); Hashizume, T.; Ota, E. [Waseda University, Tokyo (Japan). School of Science and Engineering

    2000-01-25

    The effect of operating methods of wind turbine-generator system on net power extraction under wind speed fluctuations is discussed in relation to the dynamic behavior of the system. The system is composed of a Darrieus-Savonius hybrid wind turbine and a load generator. In this paper, two types of operating method are examined; constant tip speed ratio operation for stand-alone power systems (Scheme 1) and synchronous operation for utility power systems (Scheme 2). The computed results of the net extracting power using our dynamic simulation model show that the dominant factor of power extraction in Scheme 1 is the dynamic characteristics of rotational components and that it is important to select the appropriate rated wind speed in Scheme 2. Thus, it is concluded that a conformable operating method and rated power output of the system exist for each wind condition. In particular, small-scale systems, which are smaller than approximately 10 kW-system range, are desirable to be operated under a constant tip speed ratio as stand-alone power systems. (author)

  10. Power Quality Improvement Of Grid Integrated Type I Wind Turbine Generation System Operating as DSTATCOM by d-q Control Method

    Directory of Open Access Journals (Sweden)

    S V S Phani Kumar.Ch

    2016-06-01

    Full Text Available In recent years with the excessive consumption of electrical energy, the incongruity between generation and demand, the irrational structure of World’s energy as well as the environmental pollution have become progressively more evident. It has become crucial for ecological development to reduce the consumption of conventional energy and to enhance the development and utilization of renewable energy. Wind energy and Solar are unlimited supply of renewable energy and it has no pollution. But this concept suffer from the power quality issues from grid and generator side, this paper presents a control strategy for achieving maximum benefits from these grid-interfacing inverter when installed in 3-phase 4-wire distribution systems. The inverter can be controlled to perform as a multi-function device by incorporating active power filter functionality. The inverter can thus be utilized as: 1 power converter to inject power generated from RES to the grid and 2 shunt APF (Active Power Filter to compensate current unbalance, load current harmonics, load reactive power demand and load neutral current. All of these functions may be accomplished either individually or simultaneously. With such a control, the combination of grid-interfacing inverter and the 3-phase 4-wire linear/non-linear unbalanced load at point of common coupling appears as balanced linear load to the grid. The Paper propose design of 500kW Type I Wind Generation System 250kW each with Four Leg Inverter Controlled by d-q technique operated as DSTATCOM connected to 415V 4 wire Grid and also the results are compared with conventional Unit Vector Control. The proposed d-q method reduces the %THD of system to 1.97% from 24.12% where Unit Vector Control is of 3.94% which was on higher side , this is simulated in MATLAB/SIMULINK.

  11. Multi-life-stage monitoring system based on fibre bragg grating sensors for more reliable wind turbine rotor blades: Experimental and numerical analysis of deformation and failure in composite materials

    DEFF Research Database (Denmark)

    Pereira, Gilmar Ferreira

    , design and optimisation of offshore wind turbines. The MareWint main scientific objective is to optimise the design of offshore wind turbines, maximise reliability, and minimise maintenance costs. Integrated within the innovative rotor blades work-package, this PhD project is focused on damage analysis...... are used to improve the design process, and the implemented sensor are used to control the manufacturing and operation stage of a wind turbine rotor blade. The FBG sensors measurement principle is analysed from a multi-life-stage (design, material testing, manufacturing, and operation) perspective......, and supported/validated by numerical models, software tools, signal post-processing, and experimental validation. The damage in the wind turbine rotor blade is analysed from a material perspective (fibre reinforced polymers) and used as a design property, meaning that damage is accepted in an operational wind...

  12. Software integration for automated stability analysis and design optimization of a bearingless rotor blade

    Science.gov (United States)

    Gunduz, Mustafa Emre

    Many government agencies and corporations around the world have found the unique capabilities of rotorcraft indispensable. Incorporating such capabilities into rotorcraft design poses extra challenges because it is a complicated multidisciplinary process. The concept of applying several disciplines to the design and optimization processes may not be new, but it does not currently seem to be widely accepted in industry. The reason for this might be the lack of well-known tools for realizing a complete multidisciplinary design and analysis of a product. This study aims to propose a method that enables engineers in some design disciplines to perform a fairly detailed analysis and optimization of a design using commercially available software as well as codes developed at Georgia Tech. The ultimate goal is when the system is set up properly, the CAD model of the design, including all subsystems, will be automatically updated as soon as a new part or assembly is added to the design; or it will be updated when an analysis and/or an optimization is performed and the geometry needs to be modified. Designers and engineers will be involved in only checking the latest design for errors or adding/removing features. Such a design process will take dramatically less time to complete; therefore, it should reduce development time and costs. The optimization method is demonstrated on an existing helicopter rotor originally designed in the 1960's. The rotor is already an effective design with novel features. However, application of the optimization principles together with high-speed computing resulted in an even better design. The objective function to be minimized is related to the vibrations of the rotor system under gusty wind conditions. The design parameters are all continuous variables. Optimization is performed in a number of steps. First, the most crucial design variables of the objective function are identified. With these variables, Latin Hypercube Sampling method is used

  13. Aerodynamical noise from wind turbine generators

    International Nuclear Information System (INIS)

    Jakobsen, J.; Andersen, B.

    1993-06-01

    Two extensive measurement series of noise from wind turbines have been made during different modifications of their rotors. One series focused on the influence from the tip shape on the noise, while the other series dealt with the influence from the trailing edge. The experimental layout for the two investigations was identical. The total A-weighted noise from the wind turbine was measured in 1/3 octave bands from 50 Hz to 10 kHz in 1-minute periods simultaneously with wind speed measurements. The microphone was mounted on a hard board on the ground about 40 m directly downwind of the wind turbine, and the wind speed meter was placed at the same distance upwind of the wind turbine 10 m above ground. Regression analysis was made between noise and wind speed in each 1/3 octave band to determine the spectrum at 8 m/s. During the measurements care was taken to avoid influence from background noise, and the influence from machinery noise was minimized and corrected for. Thus the results display the aerodynamic rotor noise from the wind turbines. By use of this measurement technique, the uncertainty has been reduced to 1.5 - 2 dB per 1/3 octave band in the relevant frequency range and to about 1 dB on the total A-weighted levels. (au) (10 refs.)

  14. Wind turbines - generating noise or electricity?

    International Nuclear Information System (INIS)

    Russell, Eric

    1999-01-01

    Wind turbine technology has made great strides in the past few years. Annual energy output is up by two orders of magnitude and nacelle weight and noise has been halved. Computational fluid dynamics has paid a part in advancing knowledge of air flow and turbulence around wind generators. Current research is focused on how to increase turbine size and improve efficiency. A problem is that while larger wind turbines will produce cheaper electricity, the noise problem will mean that the number of acceptable sites will decrease. The biggest wind generators will need about 800 m clearance from the nearest house. (UK)

  15. Design evolution of large wind turbine generators

    Science.gov (United States)

    Spera, D. A.

    1979-01-01

    During the past five years, the goals of economy and reliability have led to a significant evolution in the basic design--both external and internal--of large wind turbine systems. To show the scope and nature of recent changes in wind turbine designs, development of three types are described: (1) system configuration developments; (2) computer code developments; and (3) blade technology developments.

  16. Wind turbine rotor blade monitoring using digital image correlation: a comparison to aeroelastic simulations of a multi-megawatt wind turbine

    International Nuclear Information System (INIS)

    Winstroth, J; Ernst, B; Seume, J R; Schoen, L

    2014-01-01

    Optical full-field measurement methods such as Digital Image Correlation (DIC) provide a new opportunity for measuring deformations and vibrations with high spatial and temporal resolution. However, application to full-scale wind turbines is not trivial. Elaborate preparation of the experiment is vital and sophisticated post processing of the DIC results essential. In the present study, a rotor blade of a 3.2 MW wind turbine is equipped with a random black-and-white dot pattern at four different radial positions. Two cameras are located in front of the wind turbine and the response of the rotor blade is monitored using DIC for different turbine operations. In addition, a Light Detection and Ranging (LiDAR) system is used in order to measure the wind conditions. Wind fields are created based on the LiDAR measurements and used to perform aeroelastic simulations of the wind turbine by means of advanced multibody codes. The results from the optical DIC system appear plausible when checked against common and expected results. In addition, the comparison of relative out-ofplane blade deflections shows good agreement between DIC results and aeroelastic simulations

  17. Wind turbine rotor blade monitoring using digital image correlation: a comparison to aeroelastic simulations of a multi-megawatt wind turbine

    Science.gov (United States)

    Winstroth, J.; Schoen, L.; Ernst, B.; Seume, J. R.

    2014-06-01

    Optical full-field measurement methods such as Digital Image Correlation (DIC) provide a new opportunity for measuring deformations and vibrations with high spatial and temporal resolution. However, application to full-scale wind turbines is not trivial. Elaborate preparation of the experiment is vital and sophisticated post processing of the DIC results essential. In the present study, a rotor blade of a 3.2 MW wind turbine is equipped with a random black-and-white dot pattern at four different radial positions. Two cameras are located in front of the wind turbine and the response of the rotor blade is monitored using DIC for different turbine operations. In addition, a Light Detection and Ranging (LiDAR) system is used in order to measure the wind conditions. Wind fields are created based on the LiDAR measurements and used to perform aeroelastic simulations of the wind turbine by means of advanced multibody codes. The results from the optical DIC system appear plausible when checked against common and expected results. In addition, the comparison of relative out-ofplane blade deflections shows good agreement between DIC results and aeroelastic simulations.

  18. Experimental study of complex flow and turbulence structure around a turbomachine rotor blade operating behind a row of Inlet Guide Vanes (IGVS)

    Science.gov (United States)

    Soranna, Francesco

    The flow and turbulence around a rotor blade operating downstream of a row of Inlet Guide Vanes (IGV) are investigated experimentally in a refractive index matched turbomachinery facility that provides unobstructed view of the entire flow field. High resolution 2D and Stereoscopic PIV measurements are performed both at midspan and in the tip region of the rotor blade, focusing on effects of wake-blade, wake-boundary-layer and wake-wake interactions. We first examine the modification to the shape of an IGV-wake as well as to the spatial distribution of turbulence within it as the wake propagates along the rotor blade. Due to the spatially non-uniform velocity distribution, the IGV wake deforms through the rotor passage, expanding near the leading edge and shrinking near the trailing edge. The turbulence within this wake becomes spatially non-uniform and highly anisotropic as a result of interaction with the non-uniform strain rate field within the rotor passage. Several mechanisms, which are associated with rapid straining and highly non-uniform production rate (P), including negative production on the suction side of the blade, contribute to the observed trends. During IGV-wake impingement, the suction side boundary layer near the trailing edge becomes significantly thinner, with lower momentum thickness and more stable profile compared to other phases at the same location. Analysis of available terms in the integral momentum equation indicates that the phase-averaged unsteady term is the main contributor to the decrease in momentum thickness within the impinging wake. Thinning of the boundary/shear layer extends into the rotor near wake, making it narrower and increasing the phase averaged shear velocity gradients and associated production term just downstream of the trailing edge. Consequently, the turbulent kinetic energy (TKE) increases causing as much as 75% phase-dependent variations in peak TKE magnitude. Further away from the blade, the rotor wake is bent

  19. Calibration of partial safety factors for wind turbine rotor blades against fatigue; Kalibrering af partielle sikkerhedsfaktorer for udmattelse af vindmoellerotorer. Bilagsrapport

    Energy Technology Data Exchange (ETDEWEB)

    Christensen, C.J.; Ronold, K.O.; Thoegersen, M.L.

    2000-08-01

    The report describes a calibration of partial safety factors for wind turbine rotor blades subjected to fatigue loading in flapwise and edgewise bending. While earlier models - developed by the authors - dealt with such calibrations for site-specific individual turbines only, the calibration model applied herein covers an integrated analysis with different turbines on different sites and with different blade materials. The result is an optimized set of partial safety factors, i.e. a set of safety factors that lead to minimum deviation from the target reliability of the achieved reliabilities over the selected scope of turbines, sites and materials. The turbines included in the study cover rated powers of 450-600 kW. (au)

  20. Merenje vibracija i relevantnih parametara leta transportnog helikoptera Mi-8 sa revitalizovanim lopaticama nosećeg rotora / Vibration and flight data measurement on the transport helicopter Mi-8 with replaced main rotor blades

    Directory of Open Access Journals (Sweden)

    Veljko Rakonjac

    2004-11-01

    Full Text Available Rad se odnosi na merenje parametara leta transportnog helikoptera ruske proizvodnje Mi-8 sa ugrađenim originalnim, kao i revitalizovanim - delimično kompozitnim lopaticama nosećeg rotora. Cilj merenja bio je dobijanje relevantnih podataka za ocenu kvaliteta revitalizovanih lopatica usled zamene lopatica nosećeg rotora. Prikazani su oprema, postupak i analiza rezultata merenja parametara leta i vibracija, uz poseban osvrt na probleme izazvane uticajem vibracija na mernu opremu. / This paper presents helicopter flight data acquisition made on the Russian helicopter Mi-8 with its original main rotor blades as well as with regenerated, partially composite ones. The purpose of the measurement was collecting data for flight quality of the main rotor composite blades changing the actual main rotor blades. This paper also presents equipment procedures and analysis of flight data and vitration measurements with special attention to problems caused by vibration influence on equipment.

  1. Theoretical and experimental analysis of cyclic stresses in gas turbine rotor blades, taking thermal fatigue into account (low cycle fatigue). Theoretische und experimentelle Analyse der zyklischen Beanspruchung von Gasturbinenlaufschaufeln unter besonderer Beruecksichtigung der thermischen Ermuedung (low cycle fatigue)

    Energy Technology Data Exchange (ETDEWEB)

    Hoelscher, R.

    1982-08-01

    The author is concerned with determining the life of highly stressed hot components of gas turbines. The main point of the experimental and theoretical investigations is the analysis of the cyclic stresses of an uncooled turbine rotor blade of an aircraft gas turbine ATAR 101. Apart from simulating cyclic load changes of turbine blades on a model test rig, models of service life predictions are prepared and tested. (HAG).

  2. Comparación del comportamiento en la red eléctrica del aerogenerador asincrónico de jaula de ardilla y el doblemente alimentado; Comparison of the Behavior in the Electric Network of the Squirrel Cage Wind Turbine Generator and the Doubly Fed Wind Turbin

    Directory of Open Access Journals (Sweden)

    Mariely Francisco Fernández

    2011-02-01

    Full Text Available En este artículo, se lleva a cabo un análisis comparativo entre estos dos tipos de aerogeneradores. Labase para la comparación es el comportamiento del generador en el sistema sujeto a diferentes tiposperturbaciones tales como: valles de tensión, cortocircuitos, rachas de viento y cambios de carga.Para lasimulación se utiliza el SimPowerSystem del MATLAB. Sus últimas versiones tienen entre sus herramientasmodelos de turbinas y generadores eólicos que facilitan mucho el trabajo.En el caso de los GeneradoresAsincrónicos con Rotor Jaula de ardilla se analizaron tanto el caso de Condensadores Variables enParalelo como la utilización de Compensadores Estáticos de Reactivo. Ésta última permite la regulación dela tensión en el punto de conexión del Aerogenerador. Finalmente, queda demostrada y bien argumentadaen el trabajo la superioridad del generador doblemente alimentado. In this paper, a comparative analysis of these two types of wind turbine generators is made. The base forthe comparison is the behaviour of the generator and the system submitted to different disturbances suchas voltage dips, short-circuits, winds gusts and load changes. The MATLAB SimPowerSystem toolbox isused for doing these analyses. Its last version has a Wind Turbine Generator tool that facilitates the work.In the case of the Cage Induction Generator, a changing paralleled capacitor bank and a static varcompensator are supposed and analyzed. It is demonstrated that the last one is capable of supportnetwork voltage. Finally, the superiority of the Doubly Fed Induction Generator is clearly demonstrated andwell argument. 

  3. Performance Data from a Wind-Tunnel Test of Two Main-rotor Blade Designs for a Utility-Class Helicopter

    Science.gov (United States)

    Singleton, Jeffrey D.; Yeager, William T., Jr.; Wilbur, Matthew L.

    1990-01-01

    An investigation was conducted in the NASA Langley Transonic Dynamics Tunnel to evaluate an advanced main rotor designed for use on a utility class helicopter, specifically the U.S. Army UH-60A Blackhawk. This rotor design incorporated advanced twist, airfoil cross sections, and geometric planform. For evaluation purposes, the current UH-60A main rotor was also tested and is referred to as the baseline blade set. A total of four blade sets were tested. One set of both the baseline and the advanced rotors were dynamically scaled to represent a full scale helicopter rotor blade design. The remaining advanced and baseline blade sets were not dynamically scaled so as to isolate the effects of structural elasticity. The investigation was conducted in hover and at rotor advance ratios ranging from 0.15 to 0.4 at a range of nominal test medium densities from 0.00238 to 0.009 slugs/cu ft. This range of densities, coupled with varying rotor lift and propulsive force, allowed for the simulation of several vehicle gross weight and density altitude combinations. Performance data are presented for all blade sets without analysis; however, cross referencing of data with flight condition may be useful to the analyst for validating aeroelastic theories and design methodologies as well as for evaluating advanced design parameters.

  4. Improved High Temperature Superconductor Materials for Wind Turbine Generators

    DEFF Research Database (Denmark)

    Mozhaev, Peter; Khoryushin, Alexey; Mozhaeva, Julia

    2011-01-01

    Effects of yttria addition on the structural and electrical properties of the YBCO thin films are studied. The films were deposited on (LaAlO3).3-(Sr2AlTaO8).7 substrates by pulsed laser ablation from targets with different elemental composition. The contents of elements in the film depend mainly...

  5. Series pid pitch controller of large wind turbines generator

    Directory of Open Access Journals (Sweden)

    Micić Aleksandar D.

    2015-01-01

    Full Text Available For this stable process with oscillatory dynamics, characterized with small damping ratio and dominant transport delay, design of the series PID pitch controller is based on the model obtained from the open-loop process step response, filtered with the second-order Butterworth filter Fbw. Performance of the series PID pitch controller, with the filter Fbw, is analyzed by simulations of the set-point and input/output disturbance responses, including simulations with a colored noise added to the control variable. Excellent performance/robustness tradeoff is obtained, compared to the recently proposed PI pitch controllers and to the modified internal model pitch controller, developed here, which has a natural mechanism to compensate effect of dominant transport delay. [Projekat Ministarstva nauke Republike Srbije, br. III 47016

  6. 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....

  7. Low Cost Small Wind Turbine Generators for Developing Countries

    NARCIS (Netherlands)

    Ani, S.O.

    2013-01-01

    Wind energy accounts for an increasing percentage of the energy supplied to the electricity network. Electricity generation from wind is now cheaper than other renewables and almost cost competitive with other conventional sources of electricity generation. However, this impressive growth is largely

  8. Improved High Temperature Superconductor Materials for Wind Turbine Generators

    OpenAIRE

    Mozhaev, Peter; Khoryushin, Alexey; Mozhaeva, Julia; Andersen, Niels Hessel; Grivel, Jean-Claude; Hansen, Jørn Bindslev; Jacobsen, Claus Schelde

    2011-01-01

    Effects of yttria addition on the structural and electrical properties of the YBCO thin films are studied. The films were deposited on (LaAlO3).3-(Sr2AlTaO8).7 substrates by pulsed laser ablation from targets with different elemental composition. The contents of elements in the film depend mainly on the yttrium content in the target. An increase of yttrium content leads to formation of a porous film with significant improvement of current-carrying capabilities (critical current density reache...

  9. Improved high temperature superconductor materials for wind turbine generators

    Energy Technology Data Exchange (ETDEWEB)

    Mozhaev, P.B.; Khoryushin, A.V.; Mozhaeva, J.E.; Bindslev Hansen, J.; Jacobsen, Claus S. (Technical Univ. of Denmark (DTU). Physics Dept., Kgs. Lyngby (Denmark)); Andersen, Niels H.; Grivel, J.-C. (Technical Univ. of Denmark (DTU). Risoe National Lab. for Sustainable Energy, Roskilde (Denmark))

    2011-05-15

    Effects of yttria addition on the structural and electrical properties of the YBCO thin films are studied. The films were deposited on (LaAlO{sub 3}){sub .3}-(Sr{sub 2}AlTaO{sub 8}){sub .7} substrates by pulsed laser ablation from targets with different elemental composition. The contents of elements in the film depend mainly on the yttrium content in the target. An increase of yttrium content leads to formation of a porous film with significant improvement of current-carrying capabilities (critical current density reaches 35 kA/cm2 at 77 K, 5 T, and exceeds 2 MA/cm2 at 50 K, 5 T). The Y-enriched YBCO film remains c-oriented up to 600 nm thickness with no suppression of the critical current density in the film. Yttria decoration of the substrate surface prior to deposition resulted in formation of YBCO films with low strain and high crystal perfection. In contrast to the Y-enriched YBCO films, the films on yttria layers are dense. At temperatures of 77 K and above the YBCO films on yttria-decorated substrates exhibit critical current densities comparable to or better than that of the Y-enriched films. (Author)

  10. Removable bearing arrangement for a wind turbine generator

    Science.gov (United States)

    Bagepalli, Bharat Sampathkumaran; Jansen, Patrick Lee; Gadre, Aniruddha Dattatraya

    2010-06-15

    A wind generator having removable change-out bearings includes a rotor and a stator, locking bolts configured to lock the rotor and stator, a removable bearing sub-assembly having at least one shrunk-on bearing installed, and removable mounting bolts configured to engage the bearing sub-assembly and to allow the removable bearing sub-assembly to be removed when the removable mounting bolts are removed.

  11. Wind turbine/generator set and method of making same

    Science.gov (United States)

    Bevington, Christopher M.; Bywaters, Garrett L.; Coleman, Clint C.; Costin, Daniel P.; Danforth, William L.; Lynch, Jonathan A.; Rolland, Robert H.

    2013-06-04

    A wind turbine comprising an electrical generator that includes a rotor assembly. A wind rotor that includes a wind rotor hub is directly coupled to the rotor assembly via a simplified connection. The wind rotor and generator rotor assembly are rotatably mounted on a central spindle via a bearing assembly. The wind rotor hub includes an opening having a diameter larger than the outside diameter of the central spindle adjacent the bearing assembly so as to allow access to the bearing assembly from a cavity inside the wind rotor hub. The spindle is attached to a turret supported by a tower. Each of the spindle, turret and tower has an interior cavity that permits personnel to traverse therethrough to the cavity of the wind rotor hub. The wind turbine further includes a frictional braking system for slowing, stopping or keeping stopped the rotation of the wind rotor and rotor assembly.

  12. Design Tool for Direct Drive Wind Turbine Generators

    DEFF Research Database (Denmark)

    Leban, Krisztina Monika

    . A comparison of the selected machine types in view of up-scaling to 20 [MW] was performed. As an example fitness criterion, the use of active materials for the generators was considered. Based on this, suggestions for 20 [MW] generators were made. The results are discussed and future work, directions......The current work offers a comparison of the proposed machine geometries for 6 [MW] direct drive wind generator candidates with the prospective of up scaling to 20MW. The suggestions are based on a design tool especially built for this investigation. The in-built flexibility of the design tool gives...

  13. 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...

  14. Crack Propagation in Compressor Rotor Blade

    Science.gov (United States)

    2012-08-01

    Aerospace: Research and Development 86 Blenheim Crescent Ruislip, Middlesex HA4 7HB United Kingdom October 20, 2010 Distribution... Middlesex HA4 7HB United Kingdom April 20, 2011 Distribution A: Approved for public release; distribution is unlimited...September 2010, (Grant FA8655-10-1-3062), European Office of Aerospace: Research and Development, 86 Blenheim Crescent, Ruislip, Middlesex HA4 7HB

  15. Flowfield Characteristics on a Retreating Rotor Blade

    Science.gov (United States)

    2015-12-03

    Rotating Disk, IMECE2013 ASME 2013 International Mechanical Engineering Congress & Exposition. 21-NOV-13, . : , Michael Mayo, Nicholas Motahari...Number: Discipline Brandon Liberi 0.00 Jackson Merkl 0.00 Vaibhav Kumar 0.00 Nicholas Motahari 0.00 Ryan McMullen 0.00 0.00 5 NAME Total Number...horizontal and vertical pixel position of the far ends of the rotor hub and performing an inverse tan operation. Davis 7.2 software by LaVision was used to

  16. Aeroelastic characteristics of composite bearingless rotor blades

    Science.gov (United States)

    Bielawa, R. L.

    1976-01-01

    Owing to the inherent unique structural features of composite bearingless rotors, various assumptions upon which conventional rotor aeroelastic analyses are formulated, are violated. Three such features identified are highly nonlinear and time-varying structural twist, structural redundancy in bending and torsion, and for certain configurations a strongly coupled low frequency bending-torsion mode. An examination of these aeroelastic considerations and appropriate formulations required for accurate analyses of such rotor systems is presented. Also presented are test results from a dynamically scaled model rotor and complementary analytic results obtained with the appropriately reformulated aeroelastic analysis.

  17. Variable speed wind turbine generator system with current controlled voltage source inverter

    International Nuclear Information System (INIS)

    Muyeen, S.M.; Al-Durra, Ahmed; Tamura, J.

    2011-01-01

    highlights: → Current controlled voltage source inverter scheme for wind power application. → Low voltage ride through of wind farm. → Variable speed wind turbine driven permanent magnet synchronous generator-operation and control. -- Abstract: The present popular trend of wind power generation is to use variable speed wind turbine (VSWT) driving a doubly fed induction generator (DFIG), wound field synchronous generator (WFSG) or permanent magnet synchronous generator (PMSG). Among them, stability analyses of DFIG type of VSWT have already been reported in many literatures. However, transient stability and low voltage ride through (LVRT) characteristics analyses for synchronous generator type of VSWT is not sufficient enough. This paper focuses on detailed LVRT characteristic analysis of variable speed wind turbine driving a PMSG (VSWT-PMSG) with current controlled voltage source inverter (CC-VSI). Modeling and suitable control strategies for overall system are developed to augment the low voltage ride through capability of variable speed wind generator, considering recent wind farm grid code. Both symmetrical and unsymmetrical faults are analyzed as network disturbances in this paper. The permanent fault due to unsuccessful reclosing of circuit breakers is taken into consideration, which is a salient feature of this study. Moreover, the dynamic characteristic is analyzed using real wind speed data measured in Hokkaido Island, Japan. The proposed control scheme is simulated by using the standard power system simulation package PSCAD/EMTDC and results are verified by comparing that of voltage controlled voltage source inverter scheme available in power system literature.

  18. Variable speed wind turbine generator system with current controlled voltage source inverter

    Energy Technology Data Exchange (ETDEWEB)

    Muyeen, S.M., E-mail: muyeen0809@yahoo.co [Dept. of Electrical Engineering, Petroleum Institute, P.O. Box 2533, Abu Dhabi (United Arab Emirates); Al-Durra, Ahmed [Dept. of Electrical Engineering, The Petroleum Institute, P.O. Box 2533, Abu Dhabi (United Arab Emirates); Tamura, J. [Dept. of EEE, Kitami Institute of Technology, 165 Koen-cho, Kitami 090-8507 (Japan)

    2011-07-15

    highlights: {yields} Current controlled voltage source inverter scheme for wind power application. {yields} Low voltage ride through of wind farm. {yields} Variable speed wind turbine driven permanent magnet synchronous generator-operation and control. -- Abstract: The present popular trend of wind power generation is to use variable speed wind turbine (VSWT) driving a doubly fed induction generator (DFIG), wound field synchronous generator (WFSG) or permanent magnet synchronous generator (PMSG). Among them, stability analyses of DFIG type of VSWT have already been reported in many literatures. However, transient stability and low voltage ride through (LVRT) characteristics analyses for synchronous generator type of VSWT is not sufficient enough. This paper focuses on detailed LVRT characteristic analysis of variable speed wind turbine driving a PMSG (VSWT-PMSG) with current controlled voltage source inverter (CC-VSI). Modeling and suitable control strategies for overall system are developed to augment the low voltage ride through capability of variable speed wind generator, considering recent wind farm grid code. Both symmetrical and unsymmetrical faults are analyzed as network disturbances in this paper. The permanent fault due to unsuccessful reclosing of circuit breakers is taken into consideration, which is a salient feature of this study. Moreover, the dynamic characteristic is analyzed using real wind speed data measured in Hokkaido Island, Japan. The proposed control scheme is simulated by using the standard power system simulation package PSCAD/EMTDC and results are verified by comparing that of voltage controlled voltage source inverter scheme available in power system literature.

  19. Influence of Rare Earth Element Supply on Future Offshore Wind Turbine Generators

    DEFF Research Database (Denmark)

    Jensen, Bogi Bech; Abrahamsen, Asger Bech; Henriksen, Matthew Lee

    2011-01-01

    electrical machines. Such machines are utilized in applications such as electric cars, and wind turbines. This paper will examine the rare earth supply issue, in order to comment on its relevance to the wind turbine industry. The wind turbine topologies which are currently being used are compared...

  20. 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 68...

  1. Mastering Electro-Mechanical Dynamics of Large Off-Shore Direct-Drive Wind Turbine Generators

    OpenAIRE

    Kirschneck, M.

    2016-01-01

    The ever growing population of human beings on earth introduces the challenge of providing affordable, sustainable energy for everyone. Emerging markets, such as China, India or Brazil, quench their thirst for cheap energy by fossil fuels and nuclear power. At the same time researchers from all over the globe warn the public of the advent of a new, civilisation threatening disaster: climate change. Over the last two centuries mankind has gotten used to cheap but polluting energy provided by b...

  2. Real-time monitoring of wind turbine generator shaft alignment using laser measurement.

    OpenAIRE

    Mankowski, O.; Wang, Q.

    2013-01-01

    Shaft Misalignment is one of the most common sources of trouble of wind turbine drive train when rigid couplings connect the shafts. Ideal alignment of the shaft is difficult to be obtained and the couplings attached to the shaft may present angular or parallel misalignment defined also as lateral and axially misalignment. Despite misalignment is often observed in the practice, there are relatively few studies on wind turbine shaft misalignment in the literature and their results are sometime...

  3. Wind Turbine Generator System Acoustic Noise Test Report for the ARE 442 Wind Turbine

    Energy Technology Data Exchange (ETDEWEB)

    Huskey, A.; van Dam, J.

    2010-11-01

    This test was conducted on the ARE 442 as part of the U.S. Department of Energy's (DOE's) Independent Testing project. This project was established to help reduce the barriers of wind energy expansion by providing independent testing results for small turbines. In total, five turbines are being tested at the National Wind Technology Center (NWTC) as a part of this project. Acoustic noise testing is one of up to five tests that may be performed on the turbines, including duration, safety and function, power performance, and power quality tests. The acoustic noise test was conducted to the IEC 61400-11 Edition 2.1.

  4. Design and Experimental Analysis of an Exhaust Air Energy Recovery Wind Turbine Generator

    Directory of Open Access Journals (Sweden)

    Ahmad Fazlizan

    2015-06-01

    Full Text Available A vertical axis wind turbine (VAWT was positioned at the discharge outlet of a cooling tower electricity generator. To avoid a negative impact on the performance of the cooling tower and to optimize the turbine performance, the determination of the VAWT position in the discharge wind stream was conducted by experiment. The preferable VAWT position is where the higher wind velocity matches the positive torque area of the turbine rotation. With the proper matching among the VAWT configurations (blade number, airfoil type, operating tip-speed-ratio, etc. and exhaust air profile, the turbine system was not only able to recover the wasted kinetic energy, it also reduced the fan motor power consumption by 4.5% and increased the cooling tower intake air flow-rate by 11%. The VAWT had a free running rotational speed of 479 rpm, power coefficient of 10.6%, and tip-speed-ratio of 1.88. The double multiple stream tube theory was used to explain the VAWT behavior in the non-uniform wind stream. For the actual size of a cooling tower with a 2.4 m outlet diameter and powered by a 7.5 kW fan motor, it was estimated that a system with two VAWTs (side-by-side can generate 1 kW of power which is equivalent to 13% of energy recovery.

  5. Power electronic solutions for interfacing offshore wind turbine generators to medium voltage DC collection grids

    Science.gov (United States)

    Daniel, Michael T.

    Here in the early 21st century humanity is continuing to seek improved quality of life for citizens throughout the world. This global advancement is providing more people than ever with access to state-of-the-art services in areas such as transportation, entertainment, computing, communication, and so on. Providing these services to an ever-growing population while considering the constraints levied by continuing climate change will require new frontiers of clean energy to be developed. At the time of this writing, offshore wind has been proven as both a politically and economically agreeable source of clean, sustainable energy by northern European nations with many wind farms deployed in the North, Baltic, and Irish Seas. Modern offshore wind farms are equipped with an electrical system within the farm itself to aggregate the energy from all turbines in the farm before it is transmitted to shore. This collection grid is traditionally a 3-phase medium voltage alternating current (MVAC) system. Due to reactive power and other practical constraints, it is preferable to use a medium voltage direct current (MVDC) collection grid when siting farms >150 km from shore. To date, no offshore wind farm features an MVDC collection grid. However, MVDC collection grids are expected to be deployed with future offshore wind farms as they are sited further out to sea. In this work it is assumed that many future offshore wind farms may utilize an MVDC collection grid to aggregate electrical energy generated by individual wind turbines. As such, this work presents both per-phase and per-pole power electronic converter systems suitable for interfacing individual wind turbines to such an MVDC collection grid. Both interfaces are shown to provide high input power factor at the wind turbine while providing DC output current to the MVDC grid. Common mode voltage stress and circulating currents are investigated, and mitigation strategies are provided for both interfaces. A power sharing scheme for connecting multiple wind turbines in series to allow for a higher MVDC grid voltage is also proposed and analyzed. The overall results show that the proposed per-pole approach yields key advantages in areas of common mode voltage stress, circulating current, and DC link capacitance, making it the more appropriate choice of the two proposed interfaces for this application.

  6. Development of the 7.3 MW MOD-5A wind-turbine generator system

    Science.gov (United States)

    Barton, R. S.; Lucas, W. C.

    1983-12-01

    The General Electric Company Advanced Energy Programs Department is designing, under DOE/NASA sponsorship through Contract DEN 3-153, the MOD-5A wind-turbine system, which must generate electricity for less than 3.75 cents/kWh (1980 dollars). During the conceptual and preliminary design phases, the basic features were established as a result of tradeoff and optimization studies driven by minimizing the system cost of energy. During the past year, the program has been in the final design phase, and a reassessment to minimize risk has received strong emphasis in the design process. The program has progressed to the point that an agreement of sale has been reached for the first unit.

  7. Simulation for Wind Turbine Generators -- With FAST and MATLAB-Simulink Modules

    Energy Technology Data Exchange (ETDEWEB)

    Singh, M.; Muljadi, E.; Jonkman, J.; Gevorgian, V.; Girsang, I.; Dhupia, J.

    2014-04-01

    This report presents the work done to develop generator and gearbox models in the Matrix Laboratory (MATLAB) environment and couple them to the National Renewable Energy Laboratory's Fatigue, Aerodynamics, Structures, and Turbulence (FAST) program. The goal of this project was to interface the superior aerodynamic and mechanical models of FAST to the excellent electrical generator models found in various Simulink libraries and applications. The scope was limited to Type 1, Type 2, and Type 3 generators and fairly basic gear-train models. Future work will include models of Type 4 generators and more-advanced gear-train models with increased degrees of freedom. As described in this study, implementation of the developed drivetrain model enables the software tool to be used in many ways. Several case studies are presented as examples of the many types of studies that can be performed using this tool.

  8. The application of hydraulics in the 2,000 kW wind turbine generator

    Science.gov (United States)

    Onufreiczuk, S.

    1978-01-01

    A 2000 kW turbine generator using hydraulic power in two of its control systems is being built under the management of NASA Lewis Research Center. The hydraulic systems providing the control torques and forces for the yaw and blade pitch control systems are discussed. The yaw-drive-system hydraulic supply provides the power for positioning the nacelle so that the rotary axis is kept in line with the direction of the prevailing wind, as well as pressure to the yaw and high speed shaft brakes. The pitch-change-mechanism hydraulic system provides the actuation to the pitch change mechanism and permits feathering of the blades during an emergency situation. It operates in conjunction with the overall windmill computer system, with the feather control permitting slewing control flow to pass from the servo valve to the actuators without restriction.

  9. Performance and load data from Mod-0A and Mod-1 wind turbine generators

    Science.gov (United States)

    Spera, D. A.; Janetzke, D. C.

    1982-01-01

    Experimental data, together with supporting analysis, are presented on the power conversion performance and blade loading of large, horizontal-axis wind turbines tested at electric utility sites in the U.S. Four turbine rotor configurations, from 28 to 61 meters in diameter, and data from five test sites are included. Performance data are presented in the form of graphs of power and system efficiency versus free-stream wind speed. Deviations from theoretical performance are analyzed statistically. Power conversion efficiency averaged 0.34 for all tests combined, compared with 0.31 predicted. Round blade tips appeared to improve performance significantly. Cyclic blade loads were normalized to develop load factors which can be used in the design of rotors with rigid hubs.

  10. A Pole Pair Segment of a 2-MW High-Temperature Superconducting Wind Turbine Generator

    DEFF Research Database (Denmark)

    Song, Xiaowei (Andy); Mijatovic, Nenad; Kellers, Jürgen

    2017-01-01

    A 2-MW high-temperature superconducting (HTS) generator with 24 pole pairs has been designed for the wind turbine application. In order to identify potential challenges and obtain practical knowledge prior to production, a full-size stationary experimental setup, which is one pole pair segment...... and the setup in terms of the flux density, the operating condition of the HTS winding, and the force-generation capability. Finite element (FE) software MagNet is used to carry out numerical simulations. The findings show that the HTS winding in the setup is a good surrogate for these that would be used...

  11. A Pole Pair Segment of a 2 MW High Temperature Superconducting Wind Turbine Generator

    DEFF Research Database (Denmark)

    Song, Xiaowei (Andy); Mijatovic, Nenad; Kellers, Jürgen

    2016-01-01

    A 2 MW high temperature superconducting (HTS) generator with 24 pole pairs has been designed for the wind turbine application. In order to identify potential challenges and obtain practical knowledge prior to production, a fullsize stationary experimental set-up, which is one pole pair segment...... generator and the set-up in terms of the flux density, the operating condition of the HTS winding, and the force-generation capability. Finite element (FE) software MagNet is used to carry out numerical simulations. The findings show that the HTS winding in the set-up is a good surrogate...

  12. Fault Diagnosis System of Wind Turbine Generator Based on Petri Net

    Science.gov (United States)

    Zhang, Han

    Petri net is an important tool for discrete event dynamic systems modeling and analysis. And it has great ability to handle concurrent phenomena and non-deterministic phenomena. Currently Petri nets used in wind turbine fault diagnosis have not participated in the actual system. This article will combine the existing fuzzy Petri net algorithms; build wind turbine control system simulation based on Siemens S7-1200 PLC, while making matlab gui interface for migration of the system to different platforms.

  13. Opportunities for ice storage to provide ancillary services to power grids incorporating wind turbine generation

    Science.gov (United States)

    Finley, Christopher

    Power generation using wind turbines increases the electrical system balancing, regulation and ramp rate requirements due to the minute to minute variability in wind speed and the difficulty in accurately forecasting wind speeds. The addition of thermal energy storage, such as ice storage, to a building's space cooling equipment increases the operational flexibility of the equipment by allowing the owner to choose when the chiller is run. The ability of the building owner to increase the power demand from the chiller (e.g. make ice) or to decrease the power demand (e.g. melt ice) to provide electrical system ancillary services was evaluated.

  14. Mastering Electro-Mechanical Dynamics of Large Off-Shore Direct-Drive Wind Turbine Generators

    NARCIS (Netherlands)

    Kirschneck, M.

    2016-01-01

    The ever growing population of human beings on earth introduces the challenge of providing affordable, sustainable energy for everyone. Emerging markets, such as China, India or Brazil, quench their thirst for cheap energy by fossil fuels and nuclear power. At the same time researchers from all over

  15. Special Tests for the Power Electronic Converters of Wind Turbine Generators

    DEFF Research Database (Denmark)

    Helle, Lars; Senturk, Osman Selcuk; Teodorescu, Remus

    2011-01-01

    -level medium-voltage source converter topologies, of the 3L-ANPC-VSC and 3L-HB-VSC type, are considered in the paper. Both converters employ press-pack IGBT-diode pairs and interface a 6 MW wind turbine to a medium voltage grid. The power loss and thermal model data applicable for both grid and generator......Power electronic converters for wind turbines are characterized by high specific power density and high reliability. Special tests for such converters are performed in order to determine the power loss and thermal models, which are dependent of the load profile and converter structure. Two multi......-side VSCs is used to estimate the switch junction temperatures through the simulation of wind turbine grid interface operation. A discussion of the power density and reliability of the grid-side VSCs with respect to press-pack switches, gate driver, and cooling plate is included. A test set-up for a single...

  16. Wind turbine generators having wind assisted cooling systems and cooling methods

    Science.gov (United States)

    Bagepalli, Bharat [Niskayuna, NY; Barnes, Gary R [Delanson, NY; Gadre, Aniruddha D [Rexford, NY; Jansen, Patrick L [Scotia, NY; Bouchard, Jr., Charles G.; Jarczynski, Emil D [Scotia, NY; Garg, Jivtesh [Cambridge, MA

    2008-09-23

    A wind generator includes: a nacelle; a hub carried by the nacelle and including at least a pair of wind turbine blades; and an electricity producing generator including a stator and a rotor carried by the nacelle. The rotor is connected to the hub and rotatable in response to wind acting on the blades to rotate the rotor relative to the stator to generate electricity. A cooling system is carried by the nacelle and includes at least one ambient air inlet port opening through a surface of the nacelle downstream of the hub and blades, and a duct for flowing air from the inlet port in a generally upstream direction toward the hub and in cooling relation to the stator.

  17. The influence of colour on the aesthetics of wind turbine generators

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-11-01

    This paper summarises the results of studies examining the role that colour plays in reducing the visual impact of wind turbines and the development of a method for selecting the colour and pattern focusing on UK rural wind farms. Published material is reviewed, and visual factors relevant to visibility, factors influencing the choice of colour for buildings and other installations in the landscape, issues arising from the choice of colour, theories of camouflage, the testing of different colours, strategies for applying colour to wind turbines, the effectiveness of the different colours, and the effect of the different colour schemes on the visual impact of wind turbine arrays are addressed. Recommendations concerning colour selection are presented. A compact disc is provided with the paper. (UK)

  18. Modular simulation of a hybrid power system with diesel, photovoltaic inverter and wind turbine generation

    Directory of Open Access Journals (Sweden)

    Klimis Ch. Karasavvas

    2008-05-01

    Full Text Available The dynamic behavior and stability of an isolated electric power system, fed by a conventional energy plant and a re-newable energy system, is presented in this paper. Matlab/Simulink is the used software for simulating the whole system.

  19. Direct Reuse of Rare Earth Permanent Magnets - Wind Turbine Generator Case Study

    DEFF Research Database (Denmark)

    Högberg, Stig; Pedersen, Thomas Stigsberg; Bendixen, Flemming Buus

    2016-01-01

    output torque, torque ripple, and cogging torque are achievable with this segmentation technique. The influence of the thickness of the adhesive layer was analyzed, and a pole-shaping technique was applied to improve the torque characteristics. The simulation models were verified experimentally...

  20. Wind Turbine Generator Modeling and Simulation Where Rotational Speed is the Controlled Variable

    DEFF Research Database (Denmark)

    Mihet-Popa, Lucian; Blaabjerg, Frede; Boldea, Ion

    2004-01-01

    the interaction between a wind turbine and the power system. The model is intended to simulate the behaviour of the wind turbine using induction generators both during normal operation. Sample simulation results for two induction generators (2/0.5 MW) validate the fundamental issues.......To optimise the power produced in a wind turbine, the speed of the turbine should vary with the wind speed. A simple control method is proposed that will allow an induction machine to run a turbine at its maximum power coefficient. Various types of power control strategies have been suggested...... for application in variable speed wind turbines. The usual strategy is to control the power or the torque acting on the wind turbine shafts. This paper presents an alternative control strategy, where the rotational speed is the controlled variable. The paper describes a model, which is being developed to simulate...

  1. Design and fabrication of composite blades for the Mod-1 wind turbine generator

    Science.gov (United States)

    Batesole, W. R.; Gunsallus, C. T.

    1981-01-01

    The design, tooling, fabrication, quality control, and testing phases carried out to date, as well as testing still planned are described. Differences from the 150 foot blade which were introduced for cost and manufacturing improvement purposes are discussed as well as the lightning protection system installed in the blades. Actual costs and manhours expended for Blade No. 2 are provided as a base, along with a projection of costs for the blade in production.

  2. Control design for a wind turbine-generator using output feedback

    Science.gov (United States)

    Javid, S. H.; Murdoch, A.; Winkelman, J. R.

    1981-01-01

    The modeling and approach to control design for a large horizontal axis wind turbine (WT) generator are presented. The control design is based on a suboptimal output regulator which allows coordinated control of WT blade pitch angle and field voltage for the purposes of regulating electrical power and terminal voltage. Results of detailed non-linear simulation tests of this controller are shown.

  3. Wind turbine generator application places unique demands on tower design and materials

    Science.gov (United States)

    Kita, J. P.

    1978-01-01

    The most relevant contractual tower design requirements and goal for the Mod-1 tower are related to steel truss tower construction, cost-effective state-of-the-art design, a design life of 30 years, and maximum wind conditions of 120 mph at 30 feet elevation. The Mod-1 tower design approach was an iterative process. Static design loads were calculated and member sizes and overall geometry chosen with the use of finite element computer techniques. Initial tower dynamic characteristics were then combined with the dynamic properties of the other wind turbine components, and a series of complex dynamic computer programs were run to establish a dynamic load set and then a second tower design.

  4. Conceptual design of the 6 MW Mod-5A wind turbine generator

    Science.gov (United States)

    Barton, R. S.; Lucas, W. C.

    1982-01-01

    The General Electric Company, Advanced Energy Programs Department, is designing under DOE/NASA sponsorship the MOD-5A wind turbine system which must generate electricity for 3.75 cent/KWH (1980) or less. During the Conceptual Design Phase, completed in March, 1981, the MOD-5A WTG system size and features were established as a result of tradeoff and optimization studies driven by minimizing the system cost of energy (COE). This led to a 400' rotor diameter size. The MOD-5A system which resulted is defined in this paper along with the operational and environmental factors that drive various portions of the design. Development of weight and cost estimating relationships (WCER's) and their use in optimizing the MOD-5A are discussed. The results of major tradeoff studies are also presented. Subsystem COE contributions for the 100th unit are shown along with the method of computation. Detailed descriptions of the major subsystems are given, in order that the results of the various trade and optimization studies can be more readily visualized.

  5. GeneratorSE: A Sizing Tool for Variable-Speed Wind Turbine Generators

    Energy Technology Data Exchange (ETDEWEB)

    Sethuraman, Latha [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Dykes, Katherine L [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-09-22

    This report documents a set of analytical models employed by the optimization algorithms within the GeneratorSE framework. The initial values and boundary conditions employed for the generation of the various designs and initial estimates for basic design dimensions, masses, and efficiency for the four different models of generators are presented and compared with empirical data collected from previous studies and some existing commercial turbines. These models include designs applicable for variable-speed, high-torque application featuring direct-drive synchronous generators and low-torque application featuring induction generators. In all of the four models presented, the main focus of optimization is electromagnetic design with the exception of permanent-magnet and wire-wound synchronous generators, wherein the structural design is also optimized. Thermal design is accommodated in GeneratorSE as a secondary attribute by limiting the winding current densities to acceptable limits. A preliminary validation of electromagnetic design was carried out by comparing the optimized magnetic loading against those predicted by numerical simulation in FEMM4.2, a finite-element software for analyzing electromagnetic and thermal physics problems for electrical machines. For direct-drive synchronous generators, the analytical models for the structural design are validated by static structural analysis in ANSYS.

  6. Prediction of rotor blade-vortex interaction using Volterra integrals

    Energy Technology Data Exchange (ETDEWEB)

    Wong, A.; Nitzsche, F. [Carleton Univ., Dept. of Mechanical and Aerospace Engineering, Ottawa, Ontario (Canada)]. E-mail: Fred_Nitzsche@carleton.ca; Khalid, M. [National Research Council Canada, Inst. for Aerospace Research, Ottawa, Ontario (Canada)

    2004-07-01

    The theory of Volterra integral equations for nonlinear system is applied to the prediction of the nonlinear aerodynamic response of an NACA 0012 airfoil experiencing blade-vortex interaction. The phenomenon is first modeled in two-dimensions using an Euler/Navier-Stoke code, and the resulting unsteady aerodynamic flow field sequences are appropriately combined to form a training dataset. The Volterra kernels are identified in the time-domain characteristics of the selected data, which is in turn used to predict the nonlinear aerodynamic response of the airfoil. The Volterra kernel based data is then compared against a standard airfoil response. The predicted lift time histories of the airfoil are shown to be in good agreement with the aerodynamic data. (author)

  7. Development Program for Field-Repairable/Expendable Main Rotor Blades

    Science.gov (United States)

    1976-09-01

    curve, based on the data obtained from this testing. In this curve, the runout points are plotted with arrows and the fatigue curve is drawn through...paper, or abrasive wheel , blend out scratch, nick, pitting, etc. CAUTION The final polish of smooth blending will be in a spanwise direction. Remove

  8. Radial Flow Effects On A Retreating Rotor Blade

    Science.gov (United States)

    2014-05-01

    birds , marine life and even insect wings. In some cases such as helicopters, wind turbines and compres- sors, dynamic stall becomes the primary...on dynamic stall and reverse flow as applied to a helicopter rotor in forward flight and a wind turbine operating at a yaw angle. While great...occurring on a retreating blade with a focus on dynamic stall and reverse flow as applied to a helicopter rotor in forward flight and a wind turbine

  9. Metal Rubber Sensor Appliqus for Rotor Blade Air, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Thin film Metal RubberTM sensor appliqués have the potential to reduce the time, complexity and cost of measuring air flow-induced skin friction during the...

  10. Sweep-twist adaptive rotor blade : final project report.

    Energy Technology Data Exchange (ETDEWEB)

    Ashwill, Thomas D.

    2010-02-01

    Knight & Carver was contracted by Sandia National Laboratories to develop a Sweep Twist Adaptive Rotor (STAR) blade that reduced operating loads, thereby allowing a larger, more productive rotor. The blade design used outer blade sweep to create twist coupling without angled fiber. Knight & Carver successfully designed, fabricated, tested and evaluated STAR prototype blades. Through laboratory and field tests, Knight & Carver showed the STAR blade met the engineering design criteria and economic goals for the program. A STAR prototype was successfully tested in Tehachapi during 2008 and a large data set was collected to support engineering and commercial development of the technology. This report documents the methodology used to develop the STAR blade design and reviews the approach used for laboratory and field testing. The effort demonstrated that STAR technology can provide significantly greater energy capture without higher operating loads on the turbine.

  11. Fabrication and testing of prestressed composite rotor blade spar specimens

    Science.gov (United States)

    Gleich, D.

    1974-01-01

    Prestressed composite spar specimens were fabricated and evaluated by crack propagation and ballistic penetration tests. The crack propagation tests on flawed specimens showed that the prestressed composite spar construction significantly suppresses crack growth. Damage from three high velocity 30 caliber projectile hits was confined to three small holes in the ballistic test specimen. No fragmentation or crack propagation was observed indicating good ballistic damage resistance. Rotor attachment approaches and improved structural performance configurations were identified. Design theory was verified by tests. The prestressed composite spar configuration consisted of a compressively prestressed high strength ARDEFORM 301 stainless steel liner overwrapped with pretensioned S-994 fiberglass.

  12. Rotor blade full-scale fatigue testing technology and research

    DEFF Research Database (Denmark)

    Nielsen, Per Hørlyk; Berring, Peter; Pavese, Christian

    was started in the beginning of the 1980´s and has been further developed since then. Structures in composite materials are generally difficult and time consuming to test for fatigue resistance. Therefore, several methods for testing of blades have been developed and exist today. These methods...

  13. Methods for testing of geometrical down-scaled rotor blades

    DEFF Research Database (Denmark)

    Branner, Kim; Berring, Peter

    further developed since then. Structures in composite materials are generally difficult and time consuming to test for fatigue resistance. Therefore, several methods for testing of blades have been developed and exist today. Those methods are presented in [1]. Current experimental test performed on full...

  14. Prediction of rotor blade-vortex interaction using Volterra integrals

    International Nuclear Information System (INIS)

    Wong, A.; Nitzsche, F.; Khalid, M.

    2004-01-01

    The theory of Volterra integral equations for nonlinear system is applied to the prediction of the nonlinear aerodynamic response of an NACA 0012 airfoil experiencing blade-vortex interaction. The phenomenon is first modeled in two-dimensions using an Euler/Navier-Stoke code, and the resulting unsteady aerodynamic flow field sequences are appropriately combined to form a training dataset. The Volterra kernels are identified in the time-domain characteristics of the selected data, which is in turn used to predict the nonlinear aerodynamic response of the airfoil. The Volterra kernel based data is then compared against a standard airfoil response. The predicted lift time histories of the airfoil are shown to be in good agreement with the aerodynamic data. (author)

  15. IEC-TC88WG8 testing of rotor blades

    Energy Technology Data Exchange (ETDEWEB)

    Delft, D R.V. van [Delft Univ. of Technology, STEVIN Lab., Delft (Netherlands)

    1996-09-01

    In 1994 the TC88 of IEC installed a working group (WG8) to draft a guideline on blade testing. This paper gives a description of the task of the working group. Furthermore it gives a report of the progress of the work and summarizes the possible contents of the working group document on blade testing. (au)

  16. Intelligent approach to maximum power point tracking control strategy for variable-speed wind turbine generation system

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Whei-Min; Hong, Chih-Ming [Department of Electrical Engineering, National Sun Yat-Sen University, Kaohsiung 80424 (China)

    2010-06-15

    To achieve maximum power point tracking (MPPT) for wind power generation systems, the rotational speed of wind turbines should be adjusted in real time according to wind speed. In this paper, a Wilcoxon radial basis function network (WRBFN) with hill-climb searching (HCS) MPPT strategy is proposed for a permanent magnet synchronous generator (PMSG) with a variable-speed wind turbine. A high-performance online training WRBFN using a back-propagation learning algorithm with modified particle swarm optimization (MPSO) regulating controller is designed for a PMSG. The MPSO is adopted in this study to adapt to the learning rates in the back-propagation process of the WRBFN to improve the learning capability. The MPPT strategy locates the system operation points along the maximum power curves based on the dc-link voltage of the inverter, thus avoiding the generator speed detection. (author)

  17. 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.

  18. Comparison of MgB2 and Coated Conductor Based 5 MW Superconducting Wind Turbine Generator

    DEFF Research Database (Denmark)

    Abrahamsen, Asger Bech; Jensen, Bogi Bech

    2012-01-01

    conductors, but the operation temperature in range of T = 15-20 K and the engineering current density Je is smaller. We have found that a 16 pole synchronous generator with active diameter D = 4.2 m and length L = 1.5 m based on a MgB2 wire with Je = 70 A/mm2 in approximately 4 Tesla field would result...... in a wire usage in the order of 330 km. This has the potential to decrease the price of the superconductor wires in the generator by a factor of 10 compared to the coated conductors, but the cryogenics will be a challenge and is discussed. Finally we will use turbine load simulations to discuss the torque...... events that such a 5 MW generator would experience if installed in the NREL turbine....

  19. Ripple Field AC Losses in 10-MW Wind Turbine Generators With a MgB2 Superconducting Field Winding

    DEFF Research Database (Denmark)

    Liu, Dong; Polinder, Henk; Magnusson, Niklas

    2016-01-01

    Superconducting (SC) synchronous generators are proposed as a promising candidate for 10-20-MW direct-drive wind turbines because they can have low weights and small sizes. A common way of designing an SC machine is to use SC wires with high current-carrying capability in the dc field winding...... and the ac armature winding is made with copper conductors. In such generators, the dc field winding is exposed to ac magnetic field ripples due to space harmonics from the armature. In generator design phases, the ac loss caused by these ripple fields needs to be evaluated to avoid local overheating...... and an excessive cooling budget. To determine the applicability of different design solutions in terms of ac losses, this paper estimates the ac loss level of 10-MW wind generator designs employing a MgB2 SC field winding. The effects on ac losses are compared between nonmagnetic and ferromagnetic teeth...

  20. Wind Turbine Generator System Safety and Function Test Report for the Southwest Windpower H40 Wind Turbine

    Energy Technology Data Exchange (ETDEWEB)

    van Dam, J.; Link, H.; Meadors, M.; Bianchi, J.

    2002-06-01

    The objective of this test was to evaluate the safety and function characteristics of the Whisper H40 wind turbine. The general requirements of wind turbine safety and function tests are defined in the IEC standard WT01. The testing was conducted in accordance with the National Wind Technology Center (NWTC) Quality Assurance System, including the NWTC Certification Team Certification Quality Manual and the NWTC Certification Team General Quality Manual for the Testing of Wind Turbines, as well as subordinate documents. This safety and function test was performed as part of the U.S. Department of Energy's Field Verification Program for small wind turbines.

  1. Effect of wind turbine generator model and siting on wind power changes out of large WECS arrays

    Science.gov (United States)

    Schleuter, R. A.; Park, G. L.; Lotfalian, M.; Dorsey, J.; Shayanfar, H.

    1981-01-01

    Methods of reducing the WECS generation change through selection of the wind turbine model for each site, selection of an appropriate siting configuration, and wind array controls are discussed. An analysis of wind generation change from an echelon and a farm for passage of a thunderstorm is presented. Reduction of the wind generation change over ten minutes is shown to reduce the increase in spinning reserve, unloadable generation and load following requirements on unit commitment when significant WECS generation is present and the farm penetration constraint is satisfied. Controls on the blade pitch angle of all wind turbines in an array or a battery control are shown to reduce both the wind generation change out of an array and the effective farm penetration in anticipation of a storm so that the farm penetration constraint may be satisfied.

  2. Modelling and analysis of transient state during improved coupling procedure with the grid for DFIG based wind turbine generator

    Science.gov (United States)

    Kammoun, Soulaymen; Sallem, Souhir; Ben Ali Kammoun, Mohamed

    2017-11-01

    The aim of this study is to enhance DFIG based Wind Energy Conversion Systems (WECS) dynamics during grid coupling. In this paper, a system modelling and a starting/coupling procedure for this generator to the grid are proposed. The proposed non-linear system is a variable structure system (VSS) and has two different states, before and after coupling. So, two different state models are given to the system to analyse transient stability during the coupling. The given model represents well the transient state of the machine, through which, a behaviour assessment of the generator before, during and after connection is given based on simulation results. For this, a 300 kW DFIG based wind generation system model was simulated on the Matlab/SIMULINK environment. We judge the proposed procedure to be practical, smooth and stability improved.

  3. Strategies for Refining IEC 61400-2: Wind Turbine Generator Systems - Part 2: Safety of Small Wind Turbines: Preprint

    International Nuclear Information System (INIS)

    van Dam, J. J. D.; Forsyth, T. L.; Hansen, A. C.

    2001-01-01

    This paper provides a status of the changes currently being made by IEC Maintenance Team 02 (MT02) to the existing IEC 61400-2 ''Safety of small wind turbines.'' In relation to the work done by IEC MT02, work has been done by NREL and Windward Engineering under the DOE/NREL Small Wind Turbine (SWT) Project. Aeroelastic models were built and measurements taken on a Whisper H40 turbine and an AOC 15/50. Results from this study were used to verify the simple design equations. This verification will be used to evaluate how changes made in the design load estimation section of the standard work out for a broad range of turbine configurations. The work presented here builds on work performed by Van Hulle (1996)

  4. Wind turbine/generator set having a stator cooling system located between stator frame and active coils

    Science.gov (United States)

    Bevington, Christopher M.; Bywaters, Garrett L.; Coleman, Clint C.; Costin, Daniel P.; Danforth, William L.; Lynch, Jonathan A.; Rolland, Robert H.

    2012-11-13

    A wind turbine comprising an electrical generator that includes a rotor assembly. A wind rotor that includes a wind rotor hub is directly coupled to the rotor assembly via a simplified connection. The wind rotor and generator rotor assembly are rotatably mounted on a central spindle via a bearing assembly. The wind rotor hub includes an opening having a diameter larger than the outside diameter of the central spindle adjacent the bearing assembly so as to allow access to the bearing assembly from a cavity inside the wind rotor hub. The spindle is attached to a turret supported by a tower. Each of the spindle, turret and tower has an interior cavity that permits personnel to traverse therethrough to the cavity of the wind rotor hub. The wind turbine further includes a frictional braking system for slowing, stopping or keeping stopped the rotation of the wind rotor and rotor assembly.

  5. 100-kW hingeless metal wind turbine blade design, analysis and fabrication

    Science.gov (United States)

    Donham, R. E.; Schmidt, J.; Linscott, B. S.

    1975-01-01

    The design, fabrication and analysis of aluminum wind turbine rotor blades is discussed. The blades are designed to meet criteria established for a 100-kilowatt wind turbine generator operating between 8 and 60-mile-per-hour speeds at 40 revolutions per minute. The design wind speed is 18 miles per hour. Two rotor blades are used on a new facility which includes a hingeless hub and its shaft, gearbox, generator and tower. Experience shows that, for stopped rotors, safe wind speeds are strongly dependent on blade torsional and bending rigidities which the basic D spar structural blade design provides. The 0.25-inch-thick nose skin is brake/bump formed to provide the basic 'D' spar structure for the tapered, twisted blades. Adequate margins for flutter and divergence are predicted from the use of existing, correlated stopped rotor and helicopter rotor analysis programs.

  6. Methodology for Detecting Malfunctions and Evaluating the Maintenance Effectiveness in Wind Turbine Generator Bearings Using Generic versus Specific Models from SCADA Data

    Directory of Open Access Journals (Sweden)

    Miguel A. Rodríguez-López

    2018-03-01

    Full Text Available This article offers reasons to defend the use of generic behavior models as opposed to specific models in applications to determine component degradation. The term generic models refers to models based on operating data from various units, whereas specific models are calculated using operating data taken from a single unit. Moreover, generic models, used in combination with a status indicator, show excellent capacity for detecting anomalies in the equipment and for evaluating the effectiveness of the maintenance actions, resulting in lower development and maintenance costs for the operating firm. Artificial neural networks and moving means were used to calculate the degradation indicators, based on the remainders in the model. The models were developed from operating data from fourteen wind turbines monitored over several years, and applied to the detection of faults in the bearings on the non-drive end of the generator. The use of generic models may not be recommendable for detecting faults in all cases, and the suitability will depend greatly on the context of the methodology developed to detect each type of fault, according to the element causing the fault and the fault mode, since each methodology requires a greater or lesser degree of precision in the model.

  7. A two-level voltage source inverter with differentially sinusoidal pulse width modulation used in the interconnection system of a wind turbine generator

    Directory of Open Access Journals (Sweden)

    Alexandros C. Charalampidis

    2014-10-01

    Full Text Available This study analyses an interconnection system based on differentially sinusoidal pulse width modulation, used for the interconnection to the grid of a variable speed wind turbine. The modulation technique used provides specific advantages in comparison with the commonly used sinusoidal pulse width modulation (SPWM technique, such as lower DC bus voltage requirements, smaller switching losses for the same switching frequency as well as less higher harmonic content in the voltage waveforms produced. The respective control system is also described in detail. Thus this study provides a guide enabling the design of any interconnection system based on this modulation technique.

  8. Wireless Sensor Network for Helicopter Rotor Blade Vibration Monitoring: Requirements Definition and Technological Aspects

    NARCIS (Netherlands)

    Sanchez Ramirez, Andrea; Das, Kallol; Loendersloot, Richard; Tinga, Tiedo; Havinga, Paul J.M.; Basu, Biswajit

    The main rotor accounts for the largest vibration source for a helicopter fuselage and its components. However, accurate blade monitoring has been limited due to the practical restrictions on instrumenting rotating blades. The use of Wireless Sensor Networks (WSNs) for real time vibration monitoring

  9. Numerical study of aero-excitation of steam-turbine rotor blade self-oscillations

    Science.gov (United States)

    Galaev, S. A.; Makhnov, V. Yu.; Ris, V. V.; Smirnov, E. M.

    2018-05-01

    Blade aero-excitation increment is evaluated by numerical solution of the full 3D unsteady Reynolds-averaged Navier-Stokes equations governing wet steam flow in a powerful steam-turbine last stage. The equilibrium wet steam model was adopted. Blade surfaces oscillations are defined by eigen-modes of a row of blades bounded by a shroud. Grid dependency study was performed with a reduced model being a set of blades multiple an eigen-mode nodal diameter. All other computations were carried out for the entire blade row. Two cases are considered, with an original-blade row and with a row of modified (reinforced) blades. Influence of eigen-mode nodal diameter and blade reinforcing on aero-excitation increment is analyzed. It has been established, in particular, that maximum value of the aero-excitation increment for the reinforced-blade row is two times less as compared with the original-blade row. Generally, results of the study point definitely to less probability of occurrence of blade self-oscillations in case of the reinforced blade-row.

  10. KNOW-BLADE task-3.3 report: Rotor blade computations with 3D vortex generators

    DEFF Research Database (Denmark)

    Johansen, J.; Sørensen, Niels N.; Reck, M.

    2005-01-01

    The present report describes the work done in work package WP3.3: Aerodynamic Accessories in 3D in the EC project KNOW-BLADE. Vortex generators (VGs) are modelled in 3D Navier-Stokes solvers and applied on the flow around an airfoil and a wind turbineblade. Three test cases have been investigated...

  11. A Review of Sparsity-Based Methods for Analysing Radar Returns from Helicopter Rotor Blades

    Science.gov (United States)

    2016-09-01

    performance study of these algorithms in the particular problem of analysing backscatter signals from rotating blades. The report is organised as follows...provide further insight into the behaviour of the techniques. Here, the algorithms for MP, OMP, CGP, gOMP and ROMP terminate when 10 atoms are

  12. Modal Vibration Control in Periodic Time-Varying Structures with Focus on Rotor Blade Systems

    DEFF Research Database (Denmark)

    Christensen, Rene Hardam; Santos, Ilmar

    2004-01-01

    of active modal controllers. The main aim is to reduce vibrations in periodic time-varying structures. Special emphasis is given to vibration control of coupled bladed rotor systems. A state feedback modal control law is developed based on modal analysis in periodic time-varying structures. The first step...... in the procedure is a transformation of the model into a time-invariant modal form by applying the modal matrices, which are also periodic time-variant. Due to coupled rotor and blade motions complex vibration modes occur in the modal transformed state space model. This implies that the modal transformed model...

  13. Preliminary Airworthiness Evaluation AH-1S Helicopter with OGEE Tip Shape Rotor Blades

    Science.gov (United States)

    1980-05-01

    ENGINEER PROJECT PILOT HENRY ARNAIZ PROJECT ENGINEER DTIC MAY 1980 ELECTEV SEP 2 I8 Approved for public release; distribution unlimited. A UNITED STATES...compressibility effects between flights. 7. Airspeed and altitude were obtained from a boom-mounted pitot -static probe. Corrections for position error

  14. Methodology for testing subcomponents; background and motivation for subcomponent testing of wind turbine rotor blades

    DEFF Research Database (Denmark)

    Antoniou, Alexandros; Branner, Kim; Lekou, D.J.

    2016-01-01

    This report aims to provide an overview of the design methodology followed by wind turbine blade structural designers, along with the testing procedure on full scale blades which are followed by testing laboratories for blade manufacturers as required by the relevant standards and certification...... bodies’ recommendations for design and manufacturing verification. The objective of the report is not to criticize the design methodology or testing procedure and the standards thereof followed in the wind energy community, but to identify those items offered by state of the art structural design tools...... investigations performed are based on the INNWIND.EU reference 10MW horizontal axis wind turbine [1]. The structural properties and material and layout definition used within IRPWIND are defined in the INNWIND.EU report [2]. The layout of the report includes a review of the structural analysis models used...

  15. An Examination of a Pumping Rotor Blade Design for Brownout Mitigation

    Science.gov (United States)

    2015-05-18

    vision, resulting in the loss of necessary visual cues. The ab- sence of these cues greatly increases the risk of accidents. The brownout cloud can also...the intake slots are not placed at the tip and dynamic pressure is not the means of accelerating that air. One such design placed the intake slots near

  16. Report on the Audit of Performnce and Reliability of Cobra Helicopter Rotor Blades

    Science.gov (United States)

    1991-05-21

    We are providing this final report for your information and use. The audit was made from January to March 1991. The audit objective was to evaluate...internal controls. The audit was made in response to concerns raised by personnel at the Sharpe Army Depot about the K747 blade’s performance, maintenance, and reliability.

  17. Design Of Polymer Matrix Composite Materials Used For Helicopter Rotor Blades By Finite Element Method

    OpenAIRE

    Karaaslan, Nevzat Hakan

    2007-01-01

    Gelişmiş helikopter rotor paları genellikle kompozit malzemelerden üretilmektedirler ve yapılarında çeşitli hasarlara neden olabilecek yüksek derecede dinamik ve kararsız aerodinamik çevresel yüklerde çalışmaktadırlar. Bu yükleme şartlarına tekrarlı olarak maruz kalınması kompozit rotor pala yüzey kaplamalarında delaminasyon, çatlak vb. hasarlara neden olabilir. Bu tezin amacı, farklı kompozit rotor pala malzemelerinin, sonlu elemanlar yöntemi ile modellenmesi ve döner kanat yüzey kaplamaları...

  18. Numerical simulation of actuation behavior of active fiber composites in helicopter rotor blade application

    Science.gov (United States)

    Paik, Seung Hoon; Kim, Ji Yeon; Shin, Sang Joon; Kim, Seung Jo

    2004-07-01

    Smart structures incorporating active materials have been designed and analyzed to improve aerospace vehicle performance and its vibration/noise characteristics. Helicopter integral blade actuation is one example of those efforts using embedded anisotropic piezoelectric actuators. To design and analyze such integrally-actuated blades, beam approach based on homogenization methodology has been traditionally used. Using this approach, the global behavior of the structures is predicted in an averaged sense. However, this approach has intrinsic limitations in describing the local behaviors in the level of the constituents. For example, the failure analysis of the individual active fibers requires the knowledge of the local behaviors. Microscopic approach for the analysis of integrally-actuated structures is established in this paper. Piezoelectric fibers and matrices are modeled individually and finite element method using three-dimensional solid elements is adopted. Due to huge size of the resulting finite element meshes, high performance computing technology is required in its solution process. The present methodology is quoted as Direct Numerical Simulation (DNS) of the smart structure. As an initial validation effort, present analytical results are correlated with the experiments from a small-scaled integrally-actuated blade, Active Twist Rotor (ATR). Through DNS, local stress distribution around the interface of fiber and matrix can be analyzed.

  19. Design, fabrication, and testing of an ultrasonic de-icing system for helicopter rotor blades

    Science.gov (United States)

    Palacios, Jose Luis

    A low-power, non-thermal ultrasonic de-icing system is introduced as a possible substitute for current electro-thermal systems. The system generates delaminating ultrasonic transverse shear stresses at the interface of accreted ice. A PZT-4 disk driven at 28.5 KHz (radial resonance of the disk) instantaneously de-bonds 2 mm thick freezer ice layers. The ice layers are accreted to a 0.7 mm thick, 30.4 cm x 30.4 cm steel plate at an environment temperature of -20°C. A power input of 50 Watts is applied to the actuator (50 V, 19.6 KV/m), which translates to a de-icing power of 0.07 W/cm2. A finite element model of the actuator bonded to the isotropic plate is used to guide the design of the system, and predicts the transverse shear stresses at the ice interface. Wind tunnel icing tests were conducted to demonstrate the potential use of the proposed system under impact icing conditions. Both glaze ice and rime ice were generated on steel and composite plates by changing the cloud conditions of the wind tunnel. Continuous ultrasonic vibration prevented impact ice formation around the actuator location at an input power not exceeding 0.18 W/cm 2 (1.2 W/in2). As ice thickness reached a critical thickness of approximately 1.2 mm, shedding occurred on those locations where ultrasonic transverse shear stresses exceeded the shear adhesion strength of the ice. Finite element transverse shear stress predictions correlate with observed experimental impact ice de-bonding behavior. To increase the traveling distance of propagating ultrasonic waves, ultrasonic shear horizontal wave modes are studied. Wave modes providing large modal interface transverse shear stress concentration coefficients (ISCC) between the host structure (0.7 mm thick steel plate) and accreted ice (2.5 mm thick ice layer) are identified and investigated for a potential increase in the wave propagation distance. Ultrasonic actuators able to trigger these optimum wave modes are designed and fabricated. Despite exciting wave modes with high ISCC values, instantaneous ice de-bonding is not observed at input powers under 100 Watts. The two triggered ultrasonic wave modes of the structure occur at high excitation frequencies, 202 KHz and 500 KHz respectively. At these frequencies, the ultrasonic actuators do not provide large enough transverse shear stresses to exceed the shear adhesion strength of the ice layer. Neither the actuator exciting the SH1 mode (202 KHz), nor the actuator triggering the SH2 mode (500 KHz) instantaneously de-bonds ice layers with an input power under 100 Watts.

  20. Feasibility study of applying an advanced composite structure technique to the fabrication of helicopter rotor blades

    Science.gov (United States)

    Gleich, D.

    1972-01-01

    The fabrication of helicopter rotary wings from composite materials is discussed. Two composite spar specimens consisting of compressively prestressed stainless steel liner over-wrapped with pretensioned fiberglass were constructed. High liner strength and toughness together with the prescribed prestresses and final sizing of the part are achieved by means of cryogenic stretch forming of the fiber wrapped composite spar at minus 320 F, followed by release of the forming pressure and warm up to room temperature. The prestresses are chosen to provide residual compression in the metal liner under operating loads.

  1. Some practical issues in the computational design of airfoils for the helicopter main rotor blades

    Directory of Open Access Journals (Sweden)

    Kostić Ivan

    2004-01-01

    Full Text Available Very important requirement for the helicopter rotor airfoils is zero, or nearly zero moment coefficient about the aerodynamic center. Unlike the old technologies used for metal blades, modern production involving application of plastic composites has imposed the necessity of adding a flat tab extension to the blade trailing edge, thus changing the original airfoil shape. Using computer program TRANPRO, the author has developed and verified an algorithm for numerical analysis in this design stage, applied it on asymmetrical reflex camber airfoils, determined the influence of angular tab positioning on the moment coefficient value and redesigned some existing airfoils to include properly positioned tabs that satisfy very low moment coefficient requirement. .

  2. Fatigue life prediction of rotor blade composites: Validation of constant amplitude formulations with variable amplitude experiments

    International Nuclear Information System (INIS)

    Westphal, T; Nijssen, R P L

    2014-01-01

    The effect of Constant Life Diagram (CLD) formulation on the fatigue life prediction under variable amplitude (VA) loading was investigated based on variable amplitude tests using three different load spectra representative for wind turbine loading. Next to the Wisper and WisperX spectra, the recently developed NewWisper2 spectrum was used. Based on these variable amplitude fatigue results the prediction accuracy of 4 CLD formulations is investigated. In the study a piecewise linear CLD based on the S-N curves for 9 load ratios compares favourably in terms of prediction accuracy and conservativeness. For the specific laminate used in this study Boerstra's Multislope model provides a good alternative at reduced test effort

  3. Structural modelling of composite beams with application to wind turbine rotor blades

    DEFF Research Database (Denmark)

    Couturier, Philippe

    The ever changing structure and growing size of wind turbine blades put focus on the accuracy and flexibility of design tools. The present thesis is organized in four parts - all concerning the development of efficient computational methods for the structural modelling of composite beams which...... will support future growth in the rotor size.The first part presents a two-node beam element formulation, based on complementary elastic energy, valid for fully coupled beams with variable cross-section properties.The element stiffness matrix is derived by use of the six equilibrium states of the element...

  4. Advanced topics on rotor blade full-scale structural fatigue testing and requirements

    DEFF Research Database (Denmark)

    Berring, Peter; Fedorov, Vladimir; Belloni, Federico

    further developed since then. Structures in composite materials are generally difficult and time consuming to test for fatigue resistance. Therefore, several methods for testing of blades have been developed and exist today. Those methods are presented in [1]. This report deals with more advanced topics...

  5. Multi-Scale Modelling of Fatigue of Wind Turbine Rotor Blade Composites

    NARCIS (Netherlands)

    Qian, C.

    2013-01-01

    In this research, extensive fatigue tests were performed on single glass fibres and composite coupons. Comparison of the test results shows that there is a significant difference between the fibre and composite fatigue behaviour. In order to clarify this difference, a multi-scale micro-mechanical

  6. Enhancing the damping of wind turbine rotor blades, the DAMPBLADE project

    DEFF Research Database (Denmark)

    Chaviaropoulos, P.K.; Politis, E.S.; Lekou, D.J.

    2006-01-01

    A research programme enabling the development of damped wind turbine blades, having the acronym DAMPBLADE, has been supported by the EC under its 5th Framework Programme. In DAMPBLADE the following unique composite damping mechanisms were exploited aiming to increase the structural damping......: tailoring of laminate damping anisotropy, damping layers and damped polymer matrices. Additional objectives of the project were the development of the missing critical analytical technologies enabling the explicit modelling of composite structural damping and a novel ‘composite blade design capacity......’ enabling the direct prediction of aeroelastic stability and fatigue life; the development and characterization of damped composite materials; and the evaluation of new technology via the design and fabrication of damped prototype blades and their full-scale laboratory testing. After 4 years of work a 19 m...

  7. The use of cross-section warping functions in composite rotor blade analysis

    Science.gov (United States)

    Kosmatka, J. B.

    1992-01-01

    During the contracted period, our research was concentrated into three areas. The first was the development of an accurate and a computationally efficient method for predicting the cross-section warping functions in an arbitrary cross-section composed of isotropic and/or anisotropic materials. The second area of research was the development of a general higher-order one-dimensional theory for anisotropic beams. The third area of research was the development of an analytical model for assessing the extension-bend-twist coupling behavior of nonhomogeneous anisotropic beams with initial twist. In the remaining six chapters of this report, the three different research areas and associated sub-research areas are covered independently including separate introductions, theoretical developments, numerical results, and references.

  8. Fatigue life prediction of rotor blade composites: Validation of constant amplitude formulations with variable amplitude experiments

    Science.gov (United States)

    Westphal, T.; Nijssen, R. P. L.

    2014-12-01

    The effect of Constant Life Diagram (CLD) formulation on the fatigue life prediction under variable amplitude (VA) loading was investigated based on variable amplitude tests using three different load spectra representative for wind turbine loading. Next to the Wisper and WisperX spectra, the recently developed NewWisper2 spectrum was used. Based on these variable amplitude fatigue results the prediction accuracy of 4 CLD formulations is investigated. In the study a piecewise linear CLD based on the S-N curves for 9 load ratios compares favourably in terms of prediction accuracy and conservativeness. For the specific laminate used in this study Boerstra's Multislope model provides a good alternative at reduced test effort.

  9. Helicopter model rotor-blade vortex interaction impulsive noise: Scalability and parametric variations

    Science.gov (United States)

    Splettstoesser, W. R.; Schultz, K. J.; Boxwell, D. A.; Schmitz, F. H.

    1984-01-01

    Acoustic data taken in the anechoic Deutsch-Niederlaendischer Windkanal (DNW) have documented the blade vortex interaction (BVI) impulsive noise radiated from a 1/7-scale model main rotor of the AH-1 series helicopter. Averaged model scale data were compared with averaged full scale, inflight acoustic data under similar nondimensional test conditions. At low advance ratios (mu = 0.164 to 0.194), the data scale remarkable well in level and waveform shape, and also duplicate the directivity pattern of BVI impulsive noise. At moderate advance ratios (mu = 0.224 to 0.270), the scaling deteriorates, suggesting that the model scale rotor is not adequately simulating the full scale BVI noise; presently, no proved explanation of this discrepancy exists. Carefully performed parametric variations over a complete matrix of testing conditions have shown that all of the four governing nondimensional parameters - tip Mach number at hover, advance ratio, local inflow ratio, and thrust coefficient - are highly sensitive to BVI noise radiation.

  10. Optimization of Root Section for Ultra-long Steam Turbine Rotor Blade

    Czech Academy of Sciences Publication Activity Database

    Hála, Jindřich; Luxa, Martin; Šimurda, David; Bobčík, M.; Novák, O.; Rudas, B.; Synáč, J.

    2018-01-01

    Roč. 27, č. 2 (2018), s. 95-102 ISSN 1003-2169 R&D Projects: GA TA ČR(CZ) TA03020277; GA TA ČR TH02020057 Institutional support: RVO:61388998 Keywords : steam turbine * blade cascade * root section Subject RIV: BK - Fluid Dynamics OBOR OECD: Fluids and plasma physics (including surface physics) Impact factor: 0.678, year: 2016

  11. Equations of motion for a rotor blade, including gravity, pitch action and rotor speed variations

    DEFF Research Database (Denmark)

    Kallesøe, Bjarne Skovmose

    2007-01-01

    This paper extends Hodges-Dowell's partial differential equations of blade motion, by including the effects from gravity, pitch action and varying rotor speed. New equations describing the pitch action and rotor speeds are also derived. The physical interpretation of the individual terms...... in the equations is discussed. The partial differential equations of motion are approximated by ordinary differential equations of motion using an assumed mode method. The ordinary differential equations are used to simulate a sudden pitch change of a rotating blade. This work is a part of a project on pitch blade...

  12. Wind turbine blade shear web disbond detection using rotor blade operational sensing and data analysis.

    Science.gov (United States)

    Myrent, Noah; Adams, Douglas E; Griffith, D Todd

    2015-02-28

    A wind turbine blade's structural dynamic response is simulated and analysed with the goal of characterizing the presence and severity of a shear web disbond. Computer models of a 5 MW offshore utility-scale wind turbine were created to develop effective algorithms for detecting such damage. Through data analysis and with the use of blade measurements, a shear web disbond was quantified according to its length. An aerodynamic sensitivity study was conducted to ensure robustness of the detection algorithms. In all analyses, the blade's flap-wise acceleration and root-pitching moment were the clearest indicators of the presence and severity of a shear web disbond. A combination of blade and non-blade measurements was formulated into a final algorithm for the detection and quantification of the disbond. The probability of detection was 100% for the optimized wind speed ranges in laminar, 30% horizontal shear and 60% horizontal shear conditions. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  13. Multi-piece wind turbine rotor blades and wind turbines incorporating same

    Science.gov (United States)

    Moroz,; Mieczyslaw, Emilian [San Diego, CA

    2008-06-03

    A multisection blade for a wind turbine includes a hub extender having a pitch bearing at one end, a skirt or fairing having a hole therethrough and configured to mount over the hub extender, and an outboard section configured to couple to the pitch bearing.

  14. AERODYNAMIC CHARACTERISTICS CALCULATION ON SINGLE ROTOR BLADE USING FLOEFD, ANSYS FLUENT AND RC-VTOL

    Directory of Open Access Journals (Sweden)

    2016-01-01

    Full Text Available The results of computational simulation of helicopter rotor's single blade flow, for which experimental (model test data are published, are represented in this article. The calculations were made in the universal software package of CFD modeling FloEFD, which was based on the solution of averaged equations' system of Navier-Stocks, as well as in the program software RC-VTOL using the vortex method. The obtained results are compared with experimental data and modeling results in the program software ANSYS Fluent (license of TsAGI Nr. 501024. The work shows satisfactory, and in some cases good calculation data reconciliation getting with different techniques including experimental.

  15. CFD aerodynamic analysis of non-conventional airfoil sections for very large rotor blades

    International Nuclear Information System (INIS)

    Papadakis, G; Voutsinas, S; Sieros, G; Chaviaropoulos, T

    2014-01-01

    The aerodynamic performance of flat-back and elliptically shaped airfoils is analyzed on the basis of CFD simulations. Incompressible and low-Mach preconditioned compressible unsteady simulations have been carried out using the k-w SST and the Spalart Allmaras turbulence models. Time averaged lift and drag coefficients are compared to wind tunnel data for the FB 3500-1750 flat back airfoil while amplitudes and frequencies are also recorded. Prior to separation averaged lift is well predicted while drag is overestimated keeping however the trend in the tests. The CFD models considered, predict separation with a 5° delay which is reflected on the load results. Similar results are provided for a modified NACA0035 with a rounded (elliptically shaped) trailing edge. Finally as regards the dynamic characteristics in the load signals, there is fair agreement in terms of Str number but significant differences in terms of lift and drag amplitudes

  16. A comprehensive investigation of trailing edge damage in a wind turbine rotor blade

    DEFF Research Database (Denmark)

    Haselbach, Philipp Ulrich; Eder, Martin Alexander; Belloni, Federico

    2016-01-01

    to damage. Empiricism tells that adhesive joints in blades often do not fulfil their expected lifetime, leading to considerable expenses because of repair or blade replacement. Owing to the complicated structural behaviour—in conjunction with the complex loading situation—literature about the root causes...

  17. Concept - or no concept

    DEFF Research Database (Denmark)

    Thorsteinsson, Uffe

    1999-01-01

    Discussion about concept in industrial companies. A method for mapping of managerial concept in specific area is shown......Discussion about concept in industrial companies. A method for mapping of managerial concept in specific area is shown...

  18. Single-crystal-material-based induced-shear actuation for vibration reduction of helicopters with composite rotor system

    International Nuclear Information System (INIS)

    Pawar, Prashant M; Jung, Sung Nam

    2008-01-01

    In this study, an assessment is made for the helicopter vibration reduction of composite rotor blades using an active twist control concept. Special focus is given to the feasibility of implementing the benefits of the shear actuation mechanism along with elastic couplings of composite blades for achieving maximum vibration reduction. The governing equations of motion for composite rotor blades with surface bonded piezoceramic actuators are obtained using Hamilton's principle. The equations are then solved for dynamic response using finite element discretization in the spatial and time domains. A time domain unsteady aerodynamic theory with free wake model is used to obtain the airloads. A newly developed single-crystal piezoceramic material is introduced as an actuator material to exploit its superior shear actuation authority. Seven rotor blades with different elastic couplings representing stiffness properties similar to stiff-in-plane rotor blades are used to investigate the hub vibration characteristics. The rotor blades are modeled as a box beam with actuator layers bonded on the outer surface of the top and bottom of the box section. Numerical results show that a notable vibration reduction can be achieved for all the combinations of composite rotor blades. This investigation also brings out the effect of different elastic couplings on various vibration-reduction-related parameters which could be useful for the optimal design of composite helicopter blades

  19. Single-crystal-material-based induced-shear actuation for vibration reduction of helicopters with composite rotor system

    Science.gov (United States)

    Pawar, Prashant M.; Jung, Sung Nam

    2008-12-01

    In this study, an assessment is made for the helicopter vibration reduction of composite rotor blades using an active twist control concept. Special focus is given to the feasibility of implementing the benefits of the shear actuation mechanism along with elastic couplings of composite blades for achieving maximum vibration reduction. The governing equations of motion for composite rotor blades with surface bonded piezoceramic actuators are obtained using Hamilton's principle. The equations are then solved for dynamic response using finite element discretization in the spatial and time domains. A time domain unsteady aerodynamic theory with free wake model is used to obtain the airloads. A newly developed single-crystal piezoceramic material is introduced as an actuator material to exploit its superior shear actuation authority. Seven rotor blades with different elastic couplings representing stiffness properties similar to stiff-in-plane rotor blades are used to investigate the hub vibration characteristics. The rotor blades are modeled as a box beam with actuator layers bonded on the outer surface of the top and bottom of the box section. Numerical results show that a notable vibration reduction can be achieved for all the combinations of composite rotor blades. This investigation also brings out the effect of different elastic couplings on various vibration-reduction-related parameters which could be useful for the optimal design of composite helicopter blades.

  20. Determination of 2D equivalent angles of attack for a non-rotating wind turbine rotor blade

    Energy Technology Data Exchange (ETDEWEB)

    Maassen, W.H.

    1993-11-01

    For the investigation into models to compute the title subject use has been made of the Lanchester-Prandtl lifting line model. The inflow conditions are given by a uniform inflow velocity and the geometrical angles of attack at every spanwise position. A model using pressure measurements at the instrumented sections and a model using 2-dimensional C{sub L}-{alpha} data at certain spanwise positions were investigated. In section two the experimental setups of the experiments at ECN (Netherlands Energy Research Foundation) and FFA (the Aeronautical Research Institute of Sweden) are presented. In section three the theoretical background and the different methods to compute the 2D equivalent angles of attack are outlined. In section four the results of the computations of the downwash and the 2D equivalent angles of attack for the considered FFA wind tunnel experiment is presented. Finally, in section five the most important conclusions are summarized and a recommendation for the computation of the 2D equivalent angles of attack for the non-rotating blade experiments at ECN is formulated. 59 figs., 2 tabs., 3 appendices, 30 refs.

  1. A Study of Active Rotor-Blade Vibration Control using Electro-Magnetic Actuation - Part I: Theory

    DEFF Research Database (Denmark)

    Christensen, Rene Hardam; Santos, Ilmar

    2004-01-01

    actuators fixed directly in the blades. However, due to the impracticability and problems by fixing actuators in the rotating blades, it is for practical application of great interest to study whether the vibrations can be controlled using shaft-based actuators, i.e. electro-magnetic bearings...

  2. An FEM-based AI approach to model parameter identification for low vibration modes of wind turbine composite rotor blades

    Science.gov (United States)

    Navadeh, N.; Goroshko, I. O.; Zhuk, Y. A.; Fallah, A. S.

    2017-11-01

    An approach to construction of a beam-type simplified model of a horizontal axis wind turbine composite blade based on the finite element method is proposed. The model allows effective and accurate description of low vibration bending modes taking into account the effects of coupling between flapwise and lead-lag modes of vibration transpiring due to the non-uniform distribution of twist angle in the blade geometry along its length. The identification of model parameters is carried out on the basis of modal data obtained by more detailed finite element simulations and subsequent adoption of the 'DIRECT' optimisation algorithm. Stable identification results were obtained using absolute deviations in frequencies and in modal displacements in the objective function and additional a priori information (boundedness and monotony) on the solution properties.

  3. A methodology to guide the selection of composite materials in a wind turbine rotor blade design process

    Science.gov (United States)

    Bortolotti, P.; Adolphs, G.; Bottasso, C. L.

    2016-09-01

    This work is concerned with the development of an optimization methodology for the composite materials used in wind turbine blades. Goal of the approach is to guide designers in the selection of the different materials of the blade, while providing indications to composite manufacturers on optimal trade-offs between mechanical properties and material costs. The method works by using a parametric material model, and including its free parameters amongst the design variables of a multi-disciplinary wind turbine optimization procedure. The proposed method is tested on the structural redesign of a conceptual 10 MW wind turbine blade, its spar caps and shell skin laminates being subjected to optimization. The procedure identifies a blade optimum for a new spar cap laminate characterized by a higher longitudinal Young's modulus and higher cost than the initial one, which however in turn induce both cost and mass savings in the blade. In terms of shell skin, the adoption of a laminate with intermediate properties between a bi-axial one and a tri-axial one also leads to slight structural improvements.

  4. A study on rotational augmentation using CFD analysis of flow in the inboard region of the MEXICO rotor blades

    DEFF Research Database (Denmark)

    Guntur, Srinivas; Sørensen, Niels N.

    2015-01-01

    This work presents an analysis of data from existing as well as new full-rotor computational fluid dynamics computations on the MEXICO rotor, with focus on the flow around the inboard parts of the blades. The boundary layer separation characteristics on the airfoil sections in the inboard parts...

  5. Structural Optimization of Wind Turbine Rotor Blades by Multi-Level Sectional/Multibody/3DFEM Analysis

    DEFF Research Database (Denmark)

    Bottasso, C. L.; Campagnolo, F.; Croce, A.

    fully-populated cross sectional stiffness matrices. Next, a “fine”-level 3D FEM model is used for the refinement of the coarse-level solution. Improved results obtained at the level of the 3D model are utilized at the following coarse-level iteration through a heuristic modification of the design...... constraints. In addition, a buckling analysis is performed at the fine description level, which in turn affects the non-structural blade mass. The updated constraint bounds and mass make their effects felt at the next coarse-level constrained design optimization, thereby closing the loop between the coarse...

  6. Structural optimization of wind turbine rotor blades by multilevel sectional/multibody/3D-FEM analysis

    DEFF Research Database (Denmark)

    Bottasso, C. L.; Campagnolo, F.; Croce, A.

    2014-01-01

    model fully-populated cross sectional stiffness matrices. Next, a "fine"-level 3D FEM model is used for the refinement of the coarse-level solution. Improved results obtained at the level of the 3D model are utilized at the following coarse-level iteration through a heuristic modification of the design...... constraints. In addition, a buckling analysis is performed at the fine description level, which in turn affects the nonstructural blade mass. The updated constraint bounds and mass make their effects felt at the next coarse-level constrained design optimization, thereby closing the loop between the coarse...

  7. Wind turbine rotor blade with in-plane sweep and devices using the same, and methods for making the same

    Science.gov (United States)

    Wetzel, Kyle Kristopher

    2014-06-24

    A wind turbine includes a rotor having a hub and at least one blade having a torsionally rigid root, an inboard section, and an outboard section. The inboard section has a forward sweep relative to an elastic axis of the blade and the outboard section has an aft sweep.

  8. Advanced Offshore Wind Turbine/Foundation Concept for the Great Lakes

    Energy Technology Data Exchange (ETDEWEB)

    Afjeh, Abdollah A. [Univ. of Toledo, OH (United States); Windpower, Nautica [Nautica Windpower, Olmsted Falls, OH (United States); Marrone, Joseph [OCC COWI, Vancouver (Canada); Wagner, Thomas [Nautica Windpower, Olmsted Falls, OH (United States)

    2013-08-29

    was developed and implemented in FAST to extend its capability for ice load modeling.Both upwind and downwind 2-bladed rotor wind turbine designs were developed and studied. The new rotor blade uses a new twist angle distribution design and a new pitch control algorithm compared with the baseline model. The coning and tilt angles were selected for both the upwind and downwind configurations to maximize the annual energy production. The risk of blade-tower impact is greater for the downwind design, particularly under a power grid fault; however, this risk was effectively reduced by adjusting the tilt angle for the downwind configuration.

  9. Concepts of formal concept analysis

    Science.gov (United States)

    Žáček, Martin; Homola, Dan; Miarka, Rostislav

    2017-07-01

    The aim of this article is apply of Formal Concept Analysis on concept of world. Formal concept analysis (FCA) as a methodology of data analysis, information management and knowledge representation has potential to be applied to a verity of linguistic problems. FCA is mathematical theory for concepts and concept hierarchies that reflects an understanding of concept. Formal concept analysis explicitly formalizes extension and intension of a concept, their mutual relationships. A distinguishing feature of FCA is an inherent integration of three components of conceptual processing of data and knowledge, namely, the discovery and reasoning with concepts in data, discovery and reasoning with dependencies in data, and visualization of data, concepts, and dependencies with folding/unfolding capabilities.

  10. Conference on Helicopter Structures Technology, Moffett Field, Calif., November 16-18, 1977, Proceedings

    Science.gov (United States)

    1978-01-01

    Work on advanced concepts for helicopter designs is reported. Emphasis is on use of advanced composites, damage-tolerant design, and load calculations. Topics covered include structural design flight maneuver loads using PDP-10 flight dynamics model, use of 3-D finite element analysis in design of helicopter mechanical components, damage-tolerant design of the YUH-61A main rotor system, survivability of helicopters to rotor blade ballistic damage, development of a multitubular spar composite main rotor blade, and a bearingless main rotor structural design approach using advanced composites.

  11. Concept of turbines for ultrasupercritical, supercritical, and subcritical steam conditions

    Science.gov (United States)

    Mikhailov, V. E.; Khomenok, L. A.; Pichugin, I. I.; Kovalev, I. A.; Bozhko, V. V.; Vladimirskii, O. A.; Zaitsev, I. V.; Kachuriner, Yu. Ya.; Nosovitskii, I. A.; Orlik, V. G.

    2017-11-01

    The article describes the design features of condensing turbines for ultrasupercritical initial steam conditions (USSC) and large-capacity cogeneration turbines for super- and subcritical steam conditions having increased steam extractions for district heating purposes. For improving the efficiency and reliability indicators of USSC turbines, it is proposed to use forced cooling of the head high-temperature thermally stressed parts of the high- and intermediate-pressure rotors, reaction-type blades of the high-pressure cylinder (HPC) and at least the first stages of the intermediate-pressure cylinder (IPC), the double-wall HPC casing with narrow flanges of its horizontal joints, a rigid HPC rotor, an extended system of regenerative steam extractions without using extractions from the HPC flow path, and the low-pressure cylinder's inner casing moving in accordance with the IPC thermal expansions. For cogeneration turbines, it is proposed to shift the upper district heating extraction (or its significant part) to the feedwater pump turbine, which will make it possible to improve the turbine plant efficiency and arrange both district heating extractions in the IPC. In addition, in the case of using a disengaging coupling or precision conical bolts in the coupling, this solution will make it possible to disconnect the LPC in shifting the turbine to operate in the cogeneration mode. The article points out the need to intensify turbine development efforts with the use of modern methods for improving their efficiency and reliability involving, in particular, the use of relatively short 3D blades, last stages fitted with longer rotor blades, evaporation techniques for removing moisture in the last-stage diaphragm, and LPC rotor blades with radial grooves on their leading edges.

  12. COMET concept

    International Nuclear Information System (INIS)

    Alsmeyer, H.; Tromm, W.

    1995-01-01

    Studies of the COMET core catcher concept developed for a future PWR have been continued. The concept is based on the spreading of a core melt on a sacrificial layer and its erosion, until a subsequent addition of water from below causes a fragmentation of the melt. A porous solidification of the melt would then admit a complete flooding within a short period. (orig.)

  13. Concept Mapping

    Science.gov (United States)

    Technology & Learning, 2005

    2005-01-01

    Concept maps are graphical ways of working with ideas and presenting information. They reveal patterns and relationships and help students to clarify their thinking, and to process, organize and prioritize. Displaying information visually--in concept maps, word webs, or diagrams--stimulates creativity. Being able to think logically teaches…

  14. Management concepts.

    Science.gov (United States)

    Bittner, Rhonda

    2006-01-01

    Management concepts evolve through time. Health care managers can learn new concepts by evaluating classical management strategies, as well as modern-day strategies. Focusing on quality improvement and team building can help managers align the goals of their departments with the goals of the organization, consequently improving patient care.

  15. Dynamic modeling of fluid power transmissions for wind turbines

    NARCIS (Netherlands)

    Diepeveen, N.F.B.; Jarquin Laguna, A.

    2011-01-01

    Fluid power transmission for wind turbines is quietly gaining more ground/interest. The principle of the various concepts presented so far is to convert aerodynamic torque of the rotor blades into a pressurized fluid flow by means of a positive displacement pump. At the other end of the fluid power

  16. Lateral Concepts

    DEFF Research Database (Denmark)

    Gad, Christopher; Bruun Jensen, casper

    2016-01-01

    This essay discusses the complex relation between the knowledges and practices of the researcher and his/her informants in terms of lateral concepts. The starting point is that it is not the prerogative of the (STS) scholar to conceptualize the world; all our “informants” do it too. This creates...... the possibility of enriching our own conceptual repertoires by letting them be inflected by the concepts of those we study. In a broad sense, the lateral means that there is a many-to-many relation between domains of knowledge and practice. However, each specific case of the lateral is necessarily immanent...... to a particular empirical setting and form of inquiry. In this sense lateral concepts are radically empirical since it locates concepts within the field. To clarify the meaning and stakes of lateral concepts, we first make a contrast between lateral anthropology and Latour’s notion of infra-reflexivity. We end...

  17. Concept theory

    DEFF Research Database (Denmark)

    Hjørland, Birger

    2009-01-01

      Concept theory is an extremely broad, interdisciplinary and complex field of research related to many deep fields with very long historical traditions without much consensus. However, information science and knowledge organization cannot avoid relating to theories of concepts. Knowledge...... organizing systems (e.g. classification systems, thesauri and ontologies) should be understood as systems basically organizing concepts and their semantic relations. The same is the case with information retrieval systems. Different theories of concepts have different implications for how to construe......, evaluate and use such systems. Based on "a post-Kuhnian view" of paradigms this paper put forward arguments that the best understanding and classification of theories of concepts is to view and classify them in accordance with epistemological theories (empiricism, rationalism, historicism and pragmatism...

  18. Navy-New Hampshire Wind Energy Program.

    Science.gov (United States)

    1979-11-01

    wind use for both the MOD-2 and Darrieus wind turbine -generators when located on these peaks. lIT...Horizontal Axis WECS 10 2-4 Darrieus Vertical Axis Wind Turbine 12 2-5 Alcoa Design for 500 kW Vertical Axis WECS 13 3-1 Fraction of Wind Observations... Turbines In 1925, G.J.M. Darrieus patented the concept of a vertical axis wind turbine . Today, the Darrieus design has evolved to a fixed-pitch

  19. Travelling Concepts

    DEFF Research Database (Denmark)

    Simonsen, Karen-Margrethe

    2013-01-01

    Review of "Travelling Concepts, Metaphors, and Narratives: Literary and Cultural Studies in an Age of Interdisciplinary Research" ed. by Sibylle Baumgarten, Beatrice Michaelis and Ansagar Nünning, Trier; Wissenschaftlicher Verlag Trier, 2012......Review of "Travelling Concepts, Metaphors, and Narratives: Literary and Cultural Studies in an Age of Interdisciplinary Research" ed. by Sibylle Baumgarten, Beatrice Michaelis and Ansagar Nünning, Trier; Wissenschaftlicher Verlag Trier, 2012...

  20. A study of supply-chain capabilities in the Canadian wind power industry

    International Nuclear Information System (INIS)

    Wittholz, H.; Pan, D.

    2004-11-01

    In recent years, Canadian wind energy has developed to a total installed capacity of 439 MW. It is possible that by 2012, the cumulative installed wind power capacity may reach 5,600 MW, representing an investment of $8.4 billion. This analysis of the supply-chain structure in the life cycle of a wind farm identified many potential areas where Canadian companies can offer services. Opportunities for both manufacturers and service providers were presented. It was emphasized that although wind energy is a growth industry, Canada has not participated in the development and commercialization of large wind turbine technology. The technical barriers facing Canadian suppliers regarding wind turbine generator (WTG) assembly and component manufacturing were presented. Currently, Canada imports all large WTGs and components. In order to maximize benefits to the Canadian economy, it was recommended that Canadian companies acquire European technology through licences, joint ventures or foreign investment. Technology transfer funding, training and technical assistance funding, tax incentives for capital equipment and support to universities and colleges were also recommended. It was suggested that Canadian companies should focus on manufacturing rotor blades, towers, base frames, nacelle covers and spinners, flexible drive shafts, disk brakes, vibration mounts, inverters, control cabinets, and generators. tabs., figs

  1. LDV measurement of boundary layer on rotating blade surface in wind tunnel

    Science.gov (United States)

    Maeda, Takao; Kamada, Yasunari; Murata, Junsuke; Suzuki, Daiki; Kaga, Norimitsu; Kagisaki, Yosuke

    2014-12-01

    Wind turbines generate electricity due to extracting energy from the wind. The rotor aerodynamics strongly depends on the flow around blade. The surface flow on the rotating blade affects the sectional performance. The wind turbine surface flow has span-wise component due to span-wise change of airfoil section, chord length, twisted angle of blade and centrifugal force on the flow. These span-wise flow changes the boundary layer on the rotating blade and the sectional performance. Hence, the thorough understanding of blade surface flow is important to improve the rotor performance. For the purpose of clarification of the flow behaviour around the rotor blade, the velocity in the boundary layer on rotating blade surface of an experimental HAWT was measured in a wind tunnel. The velocity measurement on the blade surface was carried out by a laser Doppler velocimeter (LDV). As the results of the measurement, characteristics of surface flow are clarified. In optimum tip speed operation, the surface flow on leading edge and r/R=0.3 have large span-wise velocity which reaches 20% of sectional inflow velocity. The surface flow inboard have three dimensional flow patterns. On the other hand, the flow outboard is almost two dimensional in cross sectional plane.

  2. Basic concepts

    International Nuclear Information System (INIS)

    Dorner, B.

    1999-01-01

    The basic concepts of neutron scattering as a tool for studying the structure and the dynamics of condensed matter. Theoretical aspects are outlined, the two different cases of coherent and incoherent scattering are presented. The issue of resolution, coherence volume and the role of monochromators are also discussed. (K.A.)

  3. Simple Concepts

    Czech Academy of Sciences Publication Activity Database

    Materna, Pavel

    2013-01-01

    Roč. 28, č. 3 (2013), s. 295-319 ISSN 0353-5150 R&D Projects: GA ČR(CZ) GAP401/10/0792 Institutional support: RVO:67985955 Keywords : concept * constructions * set-theoretical paradigm Subject RIV: AA - Philosophy ; Religion

  4. Astrophysical Concepts

    CERN Document Server

    Harwit, Martin

    2006-01-01

    This classic text, aimed at senior undergraduates and beginning graduate students in physics and astronomy, presents a wide range of astrophysical concepts in sufficient depth to give the reader a quantitative understanding of the subject. Emphasizing physical concepts, the book outlines cosmic events but does not portray them in detail: it provides a series of astrophysical sketches. For this fourth edition, nearly every part of the text has been reconsidered and rewritten, new sections have been added to cover recent developments, and others have been extensively revised and brought up to date. The book begins with an outline of the scope of modern astrophysics and enumerates some of the outstanding problems faced in the field today. The basic physics needed to tackle these questions are developed in the next few chapters using specific astronomical processes as examples. The second half of the book enlarges on these topics and shows how we can obtain quantitative insight into the structure and evolution of...

  5. Introductory concepts

    International Nuclear Information System (INIS)

    Barnes, W.E.

    1983-01-01

    Physical theories are commonly classified as being either ''classical'' or ''modern''. The reasons for this distinction are both historical and substantive. Limited in the sophistication of their measuring instruments, early scientists proposed theories appropriate for the description of the simplest and most accessible physical phenomena, e.g., the trajectories of the planets. Because of the class of phenomena observed, certain beliefs came to underlie all classical theories with regard to the nature of time, space, matter, etc. For example, the idea was undisputed that an object has at all times both a definite position and velocity. Not until the interior of the atom and the nature of electromagnetic radiation were explored was it discovered that the concepts of classical physics are inadequate to deal with many phenomena. A reassessment of fundamental postulates led to the formulation of modern physics which, it is believed, successfully treats the behavior of all physical systems. To gain an understanding of the rudiments of modern physics, one proceeds as the early scientists did by first mastering the classical concepts that emerge from their intuitive picture of the world. Modifications of these concepts are subsequently introduced which allow a more accurate treatment of physical phenomena, particularly atomic and nuclear systems

  6. Stochastic modeling of lift and drag dynamics to obtain aerodynamic forces with local dynamics on rotor blade under unsteady wind inflow

    International Nuclear Information System (INIS)

    Luhur, M.R.

    2014-01-01

    This contribution provides the development of a stochastic lift and drag model for an airfoil FX 79-W-151A under unsteady wind inflow based on wind tunnel measurements. Here we present the integration of the stochastic model into a well-known standard BEM (Blade Element Momentum) model to obtain the corresponding aerodynamic forces on a rotating blade element. The stochastic model is integrated as an alternative to static tabulated data used by classical BEM. The results show that in comparison to classical BEM, the BEM with stochastic approach additionally reflects the local force dynamics and therefore provides more information on aerodynamic forces that can be used by wind turbine simulation codes. (author)

  7. Stochastic Modeling of Lift and Drag Dynamics to Obtain Aerodynamic Forces with Local Dynamics on Rotor Blade under Unsteady Wind Inflow

    Directory of Open Access Journals (Sweden)

    Muhammad Ramzan Luhur

    2014-01-01

    Full Text Available This contribution provides the development of a stochastic lift and drag model for an airfoil FX 79-W-151A under unsteady wind inflow based on wind tunnel measurements. Here we present the integration of the stochastic model into a well-known standard BEM (Blade Element Momentum model to obtain the corresponding aerodynamic forces on a rotating blade element. The stochastic model is integrated as an alternative to static tabulated data used by classical BEM. The results show that in comparison to classical BEM, the BEM with stochastic approach additionally reflects the local force dynamics and therefore provides more information on aerodynamic forces that can be used by wind turbine simulation codes

  8. Achieving more efficient operation of the nozzle vane and rotor blade rows of gas turbines through using nonaxisymmetric end wall surfaces of interblade channels

    Science.gov (United States)

    Inozemtsev, A. A.; Samokhvalov, N. Yu.; Tikhonov, A. S.

    2012-09-01

    Results from a numerical study of three versions of the end-wall generatrix of the interblade channel used in the second-stage nozzle vanes of a prospective engine's turbine are presented. Recommendations for designing nonaxisymmetric end-wall surfaces are suggested based on the obtained data.

  9. Mathematical concepts

    CERN Document Server

    Jost, Jürgen

    2015-01-01

    The main intention of this book is to describe and develop the conceptual, structural and abstract thinking of mathematics. Specific mathematical structures are used to illustrate the conceptual approach; providing a deeper insight into mutual relationships and abstract common features. These ideas are carefully motivated, explained and illustrated by examples so that many of the more technical proofs can be omitted. The book can therefore be used: ·         simply as an overview of the panorama of mathematical structures and the relations between them, to be supplemented by more detailed texts whenever you want to acquire a working knowledge of some structure ·         by itself as a first introduction to abstract mathematics ·         together with existing textbooks, to put their results into a more general perspective ·         to gain a new and hopefully deeper perspective after having studied such textbooks Mathematical Concepts has a broader scope and is less detaile...

  10. Integrated technology rotor/flight research rotor concept definition study

    Science.gov (United States)

    Carlson, R. G.; Beno, E. A.; Ulisnik, H. D.

    1983-01-01

    As part of the Integrated Technology Rotor/Flight Research Rotor (ITR/FRR) Program a number of advanced rotor system designs were conceived and investigated. From these, several were chosen that best meet the started ITR goals with emphasis on stability, reduced weight and hub drag, simplicity, low head moment stiffness, and adequate strength and fatigue life. It was concluded that obtaining low hub moment stiffness was difficult when only the blade flexibility of bearingless rotor blades is considered, unacceptably low fatigue life being the primary problem. Achieving a moderate hub moment stiffness somewhat higher than state of the art articulated rotors in production today is possible within the fatigue life constraint. Alternatively, low stiffness is possible when additional rotor elements, besides the blades themselves, provide part of the rotor flexibility. Two primary designs evolved as best meeting the general ITR requirements that presently exist. An I shaped flexbeam with an external torque tube can satisfy the general goals but would have either higher stiffness or reduced fatigue life. The elastic gimbal rotor can achieve a better combination of low stiffness and high fatigue life but would be a somewhat heavier design and possibly exhibit a higher risk of aeromechanical instability.

  11. Smart helicopter rotors optimization and piezoelectric vibration control

    CERN Document Server

    Ganguli, Ranjan; Viswamurthy, Sathyamangalam Ramanarayanan

    2016-01-01

    Exploiting the properties of piezoelectric materials to minimize vibration in rotor-blade actuators, this book demonstrates the potential of smart helicopter rotors to achieve the smoothness of ride associated with jet-engined, fixed-wing aircraft. Vibration control is effected using the concepts of trailing-edge flaps and active-twist. The authors’ optimization-based approach shows the advantage of multiple trailing-edge flaps and algorithms for full-authority control of dual trailing-edge-flap actuators are presented. Hysteresis nonlinearity in piezoelectric stack actuators is highlighted and compensated by use of another algorithm. The idea of response surfaces provides for optimal placement of trailing-edge flaps. The concept of active twist involves the employment of piezoelectrically induced shear actuation in rotating beams. Shear is then demonstrated for a thin-walled aerofoil-section rotor blade under feedback-control vibration minimization. Active twist is shown to be significant in reducing vibra...

  12. Conceptions of Parents, Conceptions of Self, and Conceptions of God.

    Science.gov (United States)

    Buri, John R.; Mueller, Rebecca A.

    Different theorists have suggested that an individual's view of God may be related to one's view of one's father, one's mother, or one's self. A study was conducted to examine the relationship of college students' conceptions of the wrathfulness-kindliness of God to their conceptions of their father's and mother's permissiveness, authoritarianism,…

  13. Performance improvement of small-scale rotors by passive blade twist control

    OpenAIRE

    Lv, Peng; Prothin, Sebastien; Mohd Zawawi, Fazila; Bénard, Emmanuel; Morlier, Joseph; Moschetta, Jean-Marc

    2015-01-01

    A passive twist control is proposed as an adaptive way to maximize the overall efficiency of the small-scale rotor blade for multifunctional aircrafts. Incorporated into a database of airfoil characteristics, Blade Element Momentum Theory is implemented to obtain the blade optimum twist rates for hover and forward flight. In order to realize the required torsion of blade between hover and forward flight, glass/epoxy laminate blade is proposed based on Centrifugal Force Induced Twist concept. ...

  14. Species concept and speciation

    Directory of Open Access Journals (Sweden)

    Amal Y. Aldhebiani

    2018-03-01

    Full Text Available Defining and recognizing a species has been a controversial issue for a long time. To determine the variation and the limitation between species, many concepts have been proposed. When a taxonomist study a particular taxa, he/she must adopted a species concept and provide a species limitation to define this taxa. In this paper some of species concepts are discussed starting from the typological species concepts to the phylogenetic concept. Positive and negative aspects of these concepts are represented in addition to their application. Keywords: Species concept, Species limitation, Species, Taxonomy, Classification

  15. The economics of a variable speed wind-diesel

    International Nuclear Information System (INIS)

    Moll, W.

    1992-01-01

    A remote community power supply system generating over 1,000 kWH/d will have at least one diesel generator running all the time. If one or more wind turbine generators are added to such a system, the diesel generator will produce less power when wind speeds are adequate, but its fuel efficiency will gradually decrease as load decreases. In the variable speed wind/diesel concept, the diesel rpm is reduced with decreasing load and a high fuel efficiency is maintained over virtually the full power range. The outputs of the diesel and wind turbine generators are fed into an inverter which synthesizes a desired voltage wave-shape with controlled magnitude and frequency. The variable speed wind/diesel concept may make vertical axis wind turbines suitable for remote community power supply because the inverter effectively isolates the power ripple of the wind turbine. A possible wind/diesel system configuration using the variable speed concept is illustrated. The economics of a 50-kW variable speed diesel and a 80-kW variable speed wind turbine generator was analyzed. Going from a constant speed diesel generator to a variable speed generator operating at 55% capacity factor, a 6% fuel saving was achieved. Adding one 80-kW wind turbine increased fuel savings to 32% at 5 m/s wind speed, but the unit energy cost rose 8.5%. At 7 m/s wind speed, fuel savings were 59% and energy savings were 7.8%. Economics are better for a peaking variable speed 50-kW wind/diesel system added to an existing diesel system to extend the installed capacity. At 7 m/s wind speed the fuel savings translate into ca $40,000 over 10 y and purchase of a $150,000 diesel generator is postponed. 7 figs., 1 tab

  16. The Extended Enterprise concept

    DEFF Research Database (Denmark)

    Larsen, Lars Bjørn; Vesterager, Johan; Gobbi, Chiara

    1999-01-01

    This paper provides an overview of the work that has been done regarding the Extended Enterprise concept in the Common Concept team of Globeman 21 including references to results deliverables concerning the development of the Extended Enterprise concept. The first section presents the basic concept...... picture from Globeman21, which illustrates the Globeman21 way of realising the Extended Enterprise concept. The second section presents the Globeman21 EE concept in a life cycle perspective, which to a large extent is based on the thoughts and ideas behind GERAM (ISO/DIS 15704)....

  17. Quantitative Concept Analysis

    NARCIS (Netherlands)

    Pavlovic, Dusko; Domenach, Florent; Ignatov, Dmitry I.; Poelmans, Jonas

    2012-01-01

    Formal Concept Analysis (FCA) begins from a context, given as a binary relation between some objects and some attributes, and derives a lattice of concepts, where each concept is given as a set of objects and a set of attributes, such that the first set consists of all objects that satisfy all

  18. The concept of cluster

    DEFF Research Database (Denmark)

    Laursen, Lea Louise Holst; Møller, Jørgen

    2013-01-01

    villages in order to secure their future. This paper will address the concept of cluster-villages as a possible approach to strengthen the conditions of contemporary Danish villages. Cluster-villages is a concept that gather a number of villages in a network-structure where the villages both work together...... to forskellige positioner ser vi en ny mulighed for landsbyudvikling, som vi kalder Clustervillages. In order to investigate the potentials and possibilities of the cluster-village concept the paper will seek to unfold the concept strategically; looking into the benefits of such concept. Further, the paper seeks...

  19. KALIMER design concept report

    Energy Technology Data Exchange (ETDEWEB)

    Park, Chang Kyu; Kim, Young Cheol; Kim, Young In; Kim, Young Gyun; Kim, Eui Kwang; Song, Hoon; Chung, Hyun Tai; Hwang, Woan; Nam, Cheol; Sub, Sim Yoon; Kim, Yeon Sik; Whan, Wim Myung; Min, Byung Tae; Yoo, Bong; Lee, Jae Han; Lee, Hyeong Yeon; Kim, Jong Bum; Koo, Gyeong Hoi; Ham, Chang Shik; Kwon, Kee Choon; Kim, Jung Taek; Park, Jae Chang; Lee, Jung Woon; Lee, Yong Hee; Kim, Chang Hwoi; Sim, Bong Shick; Hahn, Do Hee; Choi, Jong Hyeun; Kwon, Sang Woon

    1997-07-01

    KAERI is working for the development of KALIMER and work is being done for methodology development, experimental facility set up and design concept development. The development target of KALIMER has been set as to make KALIMER safer, more economic, more resistant to nuclear proliferation, and yield less impact on the environment. To achieve the target, study has been made for setting up the design concept of KALIMER including the assessment of various possible design alternatives. This report is the results of the study for the KALIMER concept study and describes the design concept of KALIMER. The developed design concept study and describes the design concept of KALIMER. The developed design concept is to be used as the starting point of the next development phase of conceptual design and the concept will be refined and modified in the conceptual design phase. The scope of the work has been set as the NSSS and essential BOP systems. For systems, NSSS and functionally related major BOP are covered. Sizing and specifying conceptual structure are covered for major equipment. Equipment and piping are arranged for the parts where the arrangement is critical in fulfilling the foresaid intention of setting up the KALIMER design concept. This report consists of 10 chapters. Chapter 2 is for the top level design requirements of KALIMER and it serves as the basis of KALIMER design concept development. Chapter 3 summarizes the KALIMER concept and describes the general design features. The remaining chapters are for specific systems. (author). 29 tabs., 37 figs.

  20. KALIMER design concept report

    International Nuclear Information System (INIS)

    Park, Chang Kyu; Kim, Young Cheol; Kim, Young In; Kim, Young Gyun; Kim, Eui Kwang; Song, Hoon; Chung, Hyun Tai; Hwang, Woan; Nam, Cheol; Sim Yoon Sub; Kim, Yeon Sik; Wim Myung Whan; Min, Byung Tae; Yoo, Bong; Lee, Jae Han; Lee, Hyeong Yeon; Kim, Jong Bum; Koo, Gyeong Hoi; Ham, Chang Shik; Kwon, Kee Choon; Kim, Jung Taek; Park, Jae Chang; Lee, Jung Woon; Lee, Yong Hee; Kim, Chang Hwoi; Sim, Bong Shick; Hahn, Do Hee; Choi, Jong Hyeun; Kwon, Sang Woon.

    1997-07-01

    KAERI is working for the development of KALIMER and work is being done for methodology development, experimental facility set up and design concept development. The development target of KALIMER has been set as to make KALIMER safer, more economic, more resistant to nuclear proliferation, and yield less impact on the environment. To achieve the target, study has been made for setting up the design concept of KALIMER including the assessment of various possible design alternatives. This report is the results of the study for the KALIMER concept study and describes the design concept of KALIMER. The developed design concept study and describes the design concept of KALIMER. The developed design concept is to be used as the starting point of the next development phase of conceptual design and the concept will be refined and modified in the conceptual design phase. The scope of the work has been set as the NSSS and essential BOP systems. For systems, NSSS and functionally related major BOP are covered. Sizing and specifying conceptual structure are covered for major equipment. Equipment and piping are arranged for the parts where the arrangement is critical in fulfilling the foresaid intention of setting up the KALIMER design concept. This report consists of 10 chapters. Chapter 2 is for the top level design requirements of KALIMER and it serves as the basis of KALIMER design concept development. Chapter 3 summarizes the KALIMER concept and describes the general design features. The remaining chapters are for specific systems. (author). 29 tabs., 37 figs

  1. PERFORMANCE - AN EVOLVING CONCEPT

    OpenAIRE

    Assist. Mirela-Oana Pintea Ph.D Student; Lect. Monica-Violeta Achim

    2010-01-01

    The concept of performance is a problematic concept and will remain so as long as the definition of company performance varies depending on the interests of users of information. On this consideration, no consensus was reached regarding the definition, methodology and performance models used. Defining this concept is realized in accordance with its objectives of users of information, while the methodology and models used are influenced by legal regulations and management policies. The approac...

  2. The Marketing Concept

    OpenAIRE

    G. Nazan Gunay

    2001-01-01

    Since the term "Market Orientation" is recognised as the critical factor in business success there has been an overwhelming increase in research issues linking market orientation with company performance. The term market orientation has been employed by scholars to indicate the implementation of the marketing concept. In order to understand market orientation, one believes that there is a need to recall what the marketing concept is. Therefore, this study reviews the "marketing concept" as a ...

  3. Empowerment: a Concept Analysis

    OpenAIRE

    Febriana, Dara

    2011-01-01

    This paper conceptually analyzed the concept of empowerment using the strategies of Walker & Avant (2005) the objective is to clarify the meaning of the concept and to clearly identify empowerment characteristic that will provide consistent definition for practice and future research. Empowerment is defined and examined using relevant resources of literatures and selected empirical referents that described empowerment as a complex and multidimensional concept. Within nursing context empowerme...

  4. New reactor concepts

    International Nuclear Information System (INIS)

    Meskens, G.; Govaerts, P.; Baugnet, J.-M.; Delbrassine, A.

    1998-11-01

    The document gives a summary of new nuclear reactor concepts from a technological point of view. Belgium supports the development of the European Pressurized-Water Reactor, which is an evolutionary concept based on the European experience in Pressurized-Water Reactors. A reorientation of the Belgian choice for this evolutionary concept may be required in case that a decision is taken to burn plutonium, when the need for flexible nuclear power plants arises or when new reactor concepts can demonstrate proved benefits in terms of safety and cost

  5. Evolving Ethical Concepts

    Science.gov (United States)

    Potter, Van Rensselaer

    1977-01-01

    Discusses the role of the scientist in changing ethical concepts from simple interpersonal and theological imperatives towards "survival imperatives that must form the core of environmental bioethics." (CS)

  6. Kierkegaard's concepts: Hypocrisy

    DEFF Research Database (Denmark)

    Fauth Hansen, Thomas Martin

    2014-01-01

    Kierkegaard’s Concepts is a comprehensive, multi-volume survey of the key concepts and categories that inform Kierkegaard’s writings. Each article is a substantial, original piece of scholarship, which discusses the etymology and lexical meaning of the relevant Danish term, traces the development...... of the concept over the course of the authorship, and explains how it functions in the wider context of Kierkegaard’s thought. Concepts have been selected on the basis of their importance for Kierkegaard’s contributions to philosophy, theology, the social sciences, literature and aesthetics, thereby making...... this volume an ideal reference work for students and scholars in a wide range of disciplines....

  7. Fundamental concepts of geometry

    CERN Document Server

    Meserve, Bruce E

    1983-01-01

    Demonstrates relationships between different types of geometry. Provides excellent overview of the foundations and historical evolution of geometrical concepts. Exercises (no solutions). Includes 98 illustrations.

  8. Identification of Flap Motion Parameters for Vibration Reduction in Helicopter Rotors with Multiple Active Trailing Edge Flaps

    Directory of Open Access Journals (Sweden)

    Uğbreve;ur Dalli

    2011-01-01

    Full Text Available An active control method utilizing the multiple trailing edge flap configuration for rotorcraft vibration suppression and blade loads control is presented. A comprehensive model for rotor blade with active trailing edge flaps is used to calculate the vibration characteristics, natural frequencies and mode shapes of any complex composite helicopter rotor blade. A computer program is developed to calculate the system response, rotor blade root forces and moments under aerodynamic forcing conditions. Rotor blade system response is calculated using the proposed solution method and the developed program depending on any structural and aerodynamic properties of rotor blades, structural properties of trailing edge flaps and properties of trailing edge flap actuator inputs. Rotor blade loads are determined first on a nominal rotor blade without multiple active trailing edge flaps and then the effects of the active flap motions on the existing rotor blade loads are investigated. Multiple active trailing edge flaps are controlled by using open loop controllers to identify the effects of the actuator signal output properties such as frequency, amplitude and phase on the system response. Effects of using multiple trailing edge flaps on controlling rotor blade vibrations are investigated and some design criteria are determined for the design of trailing edge flap controller that will provide actuator signal outputs to minimize the rotor blade root loads. It is calculated that using the developed active trailing edge rotor blade model, helicopter rotor blade vibrations can be reduced up to 36% of the nominal rotor blade vibrations.

  9. Integral Fast Reactor concept

    International Nuclear Information System (INIS)

    Till, C.E.; Chang, Y.I.

    1986-01-01

    The Integral Fast Reactor (IFR) is an innovative LMR concept, being developed at Argonne National Laboratory, that fully exploits the inherent properties of liquid metal cooling and metallic fuel to achieve breakthroughs in economics and inherent safety. This paper describes key features and potential advantages of the IFR concept, technology development status, fuel cycle economics potential, and future development path

  10. Integral Fast Reactor concept

    Energy Technology Data Exchange (ETDEWEB)

    Till, C.E.; Chang, Y.I.

    1986-01-01

    The Integral Fast Reactor (IFR) is an innovative LMR concept, being developed at Argonne National Laboratory, that fully exploits the inherent properties of liquid metal cooling and metallic fuel to achieve breakthroughs in economics and inherent safety. This paper describes key features and potential advantages of the IFR concept, technology development status, fuel cycle economics potential, and future development path.

  11. Concepts of scale

    NARCIS (Netherlands)

    Padt, F.J.G.; Arts, B.J.M.

    2014-01-01

    This chapter provides some clarity to the scale debate. It bridges a variety of approaches, definitions and jargons used in various disciplines in order to provide common ground for a concept of scale as a basis for scale-sensitive governance of the environment. The chapter introduces the concept of

  12. Children's Conceptions of Jesus

    Science.gov (United States)

    Aylward, Karen; Freathy, Rob

    2008-01-01

    This paper presents findings from a recent study investigating young children's (aged 10-11) conceptions of Jesus in England. The overall picture revealed by the study is that whilst there was a general assent amongst pupils in our sample towards an ethical and humanistic conception of the historical Jesus, there was less of a consensus about…

  13. Concepts of particle physics

    International Nuclear Information System (INIS)

    Gottfried, K.; Weisskopf, V.F.

    1984-01-01

    This volume elucidates basic and well-established concepts of particle physics for the autodidact who is curious about recent developments in fundamental physics. Elementary quantum mechanics is a background must. Contents, abridged: The evolution of the particle concept before the advent of quantum mechanics. Nonrelativistic quantum mechanics and atomic physics. Relativistic quantum theory. Nuclear phenomena. Subnuclear phenomena. Index

  14. Modeling concept drift

    DEFF Research Database (Denmark)

    Borchani, Hanen; Martinez, Ana Maria; Masegosa, Andrés R.

    2015-01-01

    An often used approach for detecting and adapting to concept drift when doing classification is to treat the data as i.i.d. and use changes in classification accuracy as an indication of concept drift. In this paper, we take a different perspective and propose a framework, based on probabilistic ...... data set from a Spanish bank....

  15. Integral fast reactor concept

    International Nuclear Information System (INIS)

    Chang, Y.I.; Marchaterre, J.F.; Sevy, R.H.

    1984-01-01

    Key features of the IFR consist of a pool-type plant arrangement, a metal fuel-based core design, and an integral fuel cycle with colocated fuel cycle facility. Both the basic concept and the technology base have been demonstrated through actual integral cycle operation in EBR-II. This paper discusses the inherent safety characteristics of the IFR concept

  16. Badminton--Teaching Concepts.

    Science.gov (United States)

    Gibbs, Marilyn J.

    1988-01-01

    Teaching four basic badminton concepts along with the usual basic skill shots allows players to develop game strategy awareness as well as mechanical skills. These four basic concepts are: (1) ready position, (2) flight trajectory, (3) early shuttle contact, and (4) camouflage. (IAH)

  17. Students’ conceptions analysis on several electricity concepts

    Science.gov (United States)

    Saputro, D. E.; Sarwanto, S.; Sukarmin, S.; Ratnasari, D.

    2018-05-01

    This research is aimed to analyse students’ conceptions on several electricity concept. This is a descriptive research with the subjects of new students of Sebelas Maret University. The numbers of the subject were 279 students that consisted of several departments such as science education, physics education, chemistry education, biology education and mathematics education in the academic year of 2017/2018. The instrument used in this research was the multiple-choice test with arguments. Based on the result of the research and analysis, it can be concluded that most of the students still find misconceptions and do not understand electricity concept on sub-topics such as electric current characteristic in the series and parallel arrangement, the value of capacitor capacitance, the influence of the capacitor charge and discharge towards the loads, and the amount of capacitor series arrangement. For the future research, it is suggested to improve students’ conceptual understanding with appropriate learning method and assessment instrument because electricity is one of physics material that closely related with students’ daily life.

  18. Clinical reasoning: concept analysis.

    Science.gov (United States)

    Simmons, Barbara

    2010-05-01

    This paper is a report of a concept analysis of clinical reasoning in nursing. Clinical reasoning is an ambiguous term that is often used synonymously with decision-making and clinical judgment. Clinical reasoning has not been clearly defined in the literature. Healthcare settings are increasingly filled with uncertainty, risk and complexity due to increased patient acuity, multiple comorbidities, and enhanced use of technology, all of which require clinical reasoning. Data sources. Literature for this concept analysis was retrieved from several databases, including CINAHL, PubMed, PsycINFO, ERIC and OvidMEDLINE, for the years 1980 to 2008. Rodgers's evolutionary method of concept analysis was used because of its applicability to concepts that are still evolving. Multiple terms have been used synonymously to describe the thinking skills that nurses use. Research in the past 20 years has elucidated differences among these terms and identified the cognitive processes that precede judgment and decision-making. Our concept analysis defines one of these terms, 'clinical reasoning,' as a complex process that uses cognition, metacognition, and discipline-specific knowledge to gather and analyse patient information, evaluate its significance, and weigh alternative actions. This concept analysis provides a middle-range descriptive theory of clinical reasoning in nursing that helps clarify meaning and gives direction for future research. Appropriate instruments to operationalize the concept need to be developed. Research is needed to identify additional variables that have an impact on clinical reasoning and what are the consequences of clinical reasoning in specific situations.

  19. Fundamental concepts of mathematics

    CERN Document Server

    Goodstein, R L

    Fundamental Concepts of Mathematics, 2nd Edition provides an account of some basic concepts in modern mathematics. The book is primarily intended for mathematics teachers and lay people who wants to improve their skills in mathematics. Among the concepts and problems presented in the book include the determination of which integral polynomials have integral solutions; sentence logic and informal set theory; and why four colors is enough to color a map. Unlike in the first edition, the second edition provides detailed solutions to exercises contained in the text. Mathematics teachers and people

  20. Advanced concepts for acceleration

    International Nuclear Information System (INIS)

    Keefe, D.

    1986-07-01

    Selected examples of advanced accelerator concepts are reviewed. Such plasma accelerators as plasma beat wave accelerator, plasma wake field accelerator, and plasma grating accelerator are discussed particularly as examples of concepts for accelerating relativistic electrons or positrons. Also covered are the pulsed electron-beam, pulsed laser accelerator, inverse Cherenkov accelerator, inverse free-electron laser, switched radial-line accelerators, and two-beam accelerator. Advanced concepts for ion acceleration discussed include the electron ring accelerator, excitation of waves on intense electron beams, and two-wave combinations

  1. German emergency management concept

    International Nuclear Information System (INIS)

    Burkart, K.

    1993-01-01

    The advantages and disadvantages of the margin and start-up value concepts (according to ICRP 40 and EU-ordinances) are explained, and it is demonstrated that the two concepts are combinable. The combined concept has the advantage of immediately providing, if required, intervention levels for the various measures to be taken, and of obliging those persons concerned with emergency protection to study and quantify, already at the planning stage, the influence of a range of accident conditions on the decision on measures. In this context, the use of computerized decision support systems which are currently being developed is indispensable. (orig./DG) [de

  2. Advanced fusion concepts program

    International Nuclear Information System (INIS)

    Dove, W.F.

    1978-01-01

    While the prospects for the eventual development of a tokamak-based fusion reactor appear promising at the present time, the Department of Energy maintains a vigorous program in alternate magnetic fusion concepts. Several of the concepts presently supported include the toroidal reversed field pinch, Tormac, Elmo Bumpy Torus, and various linear options. Recent technical accomplishments and program evaluations indicate that the possibility now exists for undertaking the next development stage, a proof-of-principle experiment, for a few of the most promising alternate concepts

  3. Radiation promotive concept

    International Nuclear Information System (INIS)

    Shebaita, M.K.

    1975-01-01

    The concept of radiation promotion was proposed in this study. The proposal of this concept was dependent upon stimulation in growth weight of survived chicks when fertile eggs were exposed to 60 Co gamma radiation. It was found that female chick (Promotive Sex) responded to this proposal concept rather than the male. Moreover, the dose level of 640 rads was found to be the Promotive Dose. It is important before applying ionizing radiation as a growth promotive to take into consideration whether you want increasing egg or meat production, as meat promotion in layers breed is bound to decrease egg production. (orig.) [de

  4. The technological conception

    International Nuclear Information System (INIS)

    Parrochia, D.

    1998-01-01

    The 'technological conception' examines how a project can be concretized or how it is possible to 'conceive', i.e. to produce operative ideas that can be directly use. The first part of this book, called 'concepts and methods', analyzes the logics of conceiving and its philosophy in the construction of its objects and in the management of its programs or projects. The second part is devoted to some exemplary technologies: roads, tunnels, bridges, dams, nuclear power plants, aerospace constructions, and analyzes different concrete logics of technological conception. Finally, the author shows how todays conception faces the risks and complexity increase of systems and considers the possibility of an entirely automated manufacturing shop in the future. (J.S.)

  5. Stormwater Management Concept Information

    Data.gov (United States)

    Montgomery County of Maryland — A stormwater management concept is a statement or drawing, or both, describing the manner in which stormwater runoff from a proposed development will be controlled...

  6. Common tester platform concept.

    Energy Technology Data Exchange (ETDEWEB)

    Hurst, Michael James

    2008-05-01

    This report summarizes the results of a case study on the doctrine of a common tester platform, a concept of a standardized platform that can be applicable across the broad spectrum of testing requirements throughout the various stages of a weapons program, as well as across the various weapons programs. The common tester concept strives to define an affordable, next-generation design that will meet testing requirements with the flexibility to grow and expand; supporting the initial development stages of a weapons program through to the final production and surveillance stages. This report discusses a concept investing key leveraging technologies and operational concepts combined with prototype tester-development experiences and practical lessons learned gleaned from past weapons programs.

  7. Concepts of radiation protection

    International Nuclear Information System (INIS)

    2013-01-01

    This seventh chapter presents the concepts and principles of safety and radiation protection, emergency situations; NORM and TENORM; radiation protection care; radiation protection plan; activities of the radiation protection service; practical rules of radiation protection and the radiation symbol

  8. Concept medium programme

    DEFF Research Database (Denmark)

    Bjerrum, Peter

    2005-01-01

    The present essay is an attempt to determine the architectural project of the 21st century in relation to a modern conception of space as the medium of architecture, and of sociality as its program......The present essay is an attempt to determine the architectural project of the 21st century in relation to a modern conception of space as the medium of architecture, and of sociality as its program...

  9. Concept medium program

    DEFF Research Database (Denmark)

    Bjerrum, Peter

    2003-01-01

    The present essays is an attempt to dertermine the architecural project of the 21st century in realation to a modern conception of space as the medium of architecture, and of society as its program. This attempt adopts the internal point of view of an architect in describing a modern architectural...... project within the framework: concept - program, these notions being concieved as spatial representations primarily and immediately "given" to architecture....

  10. Innovative confinement concepts workshop

    International Nuclear Information System (INIS)

    Kirkpatrick, R.C.

    1998-01-01

    The Innovative Confinement Concepts Workshop occurred in California during the week preceding the Second Symposium on Current Trends in International Fusion Research. An informal report was made to the Second Symposium. A summary of the Workshop concluded that some very promising ideas were presented, that innovative concept development is a central element of the restructured US DOE. Fusion Energy Sciences program, and that the Workshop should promote real scientific progress in fusion

  11. Alternative fusion concepts

    International Nuclear Information System (INIS)

    Rostagni, G.

    1981-01-01

    The paper reports the discussions and statements made by the participants on the actual state and future of five different approaches on the fusion concept; they are the following: bumpy torus, reversed-field pinch, open-ended configurations, compact toroids and stellarators. Tables show for each concept parameters that represent the achieved results; data expected for future devices and extrapolations on reactor requirements are included

  12. Data governance implementation concept

    OpenAIRE

    Ullrichová, Jana

    2016-01-01

    This master´s thesis discusses concept of implementation for data governance. The theoretical part of this thesis is about data governance. It explains why data are important for company, describes definitoons of data governance, its history, its components, its principles and processes and fitting in company. Theoretical part is amended with examples of data governance failures and banking specifics. The main goal of this thesis is to create a concept for implementing data governance and its...

  13. Concepts of classical optics

    CERN Document Server

    Strong, John

    1958-01-01

    An intermediate course in optics, this volume explores both experimental and theoretical concepts, offering practical knowledge of geometrical optics that will enhance students' comprehension of any relevant applied science. Its exposition of the concepts of classical optics is presented with a minimum of mathematical detail but presumes some knowledge of calculus, vectors, and complex numbers.Subjects include light as wave motion; superposition of wave motions; electromagnetic waves; interaction of light and matter; velocities and scattering of light; polarized light and dielectric boundarie

  14. Concept of contracting authority

    OpenAIRE

    Kasiliauskaitė, Vitalija

    2016-01-01

    Concept of Contracting Authority Law on Public Procurement the procurement concept implies the conclusion that public procurement be declared only such purchases are carried out by the contracting authority. The contracting authorities can be a subject of state and municipal management institutes, whose assignment authority is determined by a functional approach. Also, contracting authorities may be public and legal entities, but that the public interest and operates non-commercial activities...

  15. Assessment of fuel concepts

    International Nuclear Information System (INIS)

    Bailey, W.J.; Barner, J.O.

    1978-01-01

    The relative merits of various LWR UO 2 fuel concepts with the potential for improved power-ramping capability were qualitatively assessed. In the evaluation, it was determined that of the various concepts being considered, those that presently possess an adequately developed experience base include annular pellets, cladding coated with graphite on the inner surface, and packed-particle fuel. Therefore, these were selected for initial evaluation as part of the Fuel Performance Improvement Program. For this program, graphite-coated cladding is being used in conjunction with annular pellet fuel as one of the concepts with the anticipation of gaining the advantage of the combined improvements. The report discusses the following: the criteria used to evaluate the candidate fuel concepts; a comparison of the concepts selected for irradiation with the criteria, including a general description of their experience bases; and a general discussion of other candidate concepts, including identifying those which may be considered for out-of-reactor evaluation as part of this program, those for which the results of other programs will be monitored, and those which have been deleted from further consideration at this time

  16. Signal Separation of Helicopter Radar Returns Using Wavelet-Based Sparse Signal Optimisation

    Science.gov (United States)

    2016-10-01

    helicopter from the composite radar returns. The received signal consists of returns from the rotating main and tail rotor blades, the helicopter body...is used to separate the main and tail rotor blade components of a helicopter from the composite radar returns. The received signal consists of returns...Two algorithms are presented in the report to separately extract main rotor blade returns and tail rotor blade returns from the composite signal

  17. Teamwork: a concept analysis.

    Science.gov (United States)

    Xyrichis, Andreas; Ream, Emma

    2008-01-01

    This paper is a report of an analysis of the concept of teamwork. Teamwork is seen as an important facilitator in delivering quality healthcare services internationally. However, research studies of teamwork in health care are criticized for lacking a basic conceptual understanding of what this concept represents. A universal definition for healthcare settings and professionals is missing from published literature. Walker and Avant's approach was used to guide this concept analysis. Literature searches used bibliographic databases (Medline, CINAHL, Web of Science, Proquest CSA), internet search engines (GoogleScholar), and hand searches. Literature published between 1976 and 2006 was reviewed but only material in English was included. Based on the analysis undertaken, teamwork is proposed as a dynamic process involving two or more healthcare professionals with complementary backgrounds and skills, sharing common health goals and exercising concerted physical and mental effort in assessing, planning, or evaluating patient care. This is accomplished through interdependent collaboration, open communication and shared decision-making, and generates value-added patient, organizational and staff outcomes. Praising the value of teamwork without a common understanding of what this concept represents endangers both research into this way of working and its effective utilization in practice. The proposed definition helps reconcile discrepancies between how this concept is understood by nurses and doctors, as well as allied health professionals. A common understanding can facilitate communication in educational, research and clinical settings and is imperative for improving clarity and validity of future research.

  18. Concept Analysis: Music Therapy.

    Science.gov (United States)

    Murrock, Carolyn J; Bekhet, Abir K

    2016-01-01

    Down through the ages, music has been universally valued for its therapeutic properties based on the psychological and physiological responses in humans. However, the underlying mechanisms of the psychological and physiological responses to music have been poorly identified and defined. Without clarification, a concept can be misused, thereby diminishing its importance for application to nursing research and practice. The purpose of this article was for the clarification of the concept of music therapy based on Walker and Avant's concept analysis strategy. A review of recent nursing and health-related literature covering the years 2007-2014 was performed on the concepts of music, music therapy, preferred music, and individualized music. As a result of the search, the attributes, antecedents, and consequences of music therapy were identified, defined, and used to develop a conceptual model of music therapy. The conceptual model of music therapy provides direction for developing music interventions for nursing research and practice to be tested in various settings to improve various patient outcomes. Based on Walker and Avant's concept analysis strategy, model and contrary cases are included. Implications for future nursing research and practice to use the psychological and physiological responses to music therapy are discussed.

  19. Development of numerical concepts

    Directory of Open Access Journals (Sweden)

    Sabine Peucker

    2013-06-01

    Full Text Available The development of numerical concepts is described from infancy to preschool age. Infants a few days old exhibit an early sensitivity for numerosities. In the course of development, nonverbal mental models allow for the exact representation of small quantities as well as changes in these quantities. Subitising, as the accurate recognition of small numerosities (without counting, plays an important role. It can be assumed that numerical concepts and procedures start with insights about small numerosities. Protoquantitative schemata comprise fundamental knowledge about quantities. One-to-one-correspondence connects elements and numbers, and, for this reason, both quantitative and numerical knowledge. If children understand that they can determine the numerosity of a collection of elements by enumerating the elements, they have acquired the concept of cardinality. Protoquantitative knowledge becomes quantitative if it can be applied to numerosities and sequential numbers. The concepts of cardinality and part-part-whole are key to numerical development. Developmentally appropriate learning and teaching should focus on cardinality and part-part-whole concepts.

  20. Faith: a concept analysis.

    Science.gov (United States)

    Dyess, Susan Macleod

    2011-12-01

    This paper reports a concept analysis of faith. There are numerous scholars who consider spirituality and religiosity as they relate to health and nursing. Faith is often implied as linked to these concepts but deserves distinct exploration. In addition, as nursing practice conducted within communities of faith continues to emerge, concept clarification of faith is warranted. Qualitative analysis deliberately considered the concept of faith within the lens of Margaret Newman's health as expanding consciousness. Data sources used included a secondary analysis of stories collected within a study conducted in 2008, two specific reconstructed stories, the identification of attributes noted within these various stories and selected philosophical literature from 1950 to 2009.  A definition was identified from the analysis; faith is an evolving pattern of believing, that grounds and guides authentic living and gives meaning in the present moment of inter-relating. Four key attributes of faith were also identified as focusing on beliefs, foundational meaning for life, living authentically in accordance with beliefs, and interrelating with self, others and/or Divine. Although a seemingly universal concept, faith was defined individually. Faith appeared to be broader than spiritual practices and religious ritual and became the very foundation that enabled human beings to make sense of their world and circumstances. More work is needed to understand how faith community nursing can expand the traditional understanding of denominationally defined faith community practices and how nurses can support faith for individuals with whom they encounter within all nursing practice. © 2011 Blackwell Publishing Ltd.

  1. Reusable platform concepts

    International Nuclear Information System (INIS)

    Gudmestad, O.T.; Sparby, B.K.; Stead, B.L.

    1993-01-01

    There is an increasing need to reduce costs of offshore production facilities in order to make development of offshore fields profitable. For small fields with short production time there is in particular a need to investigate ways to reduce costs. The idea of platform reuse is for such fields particularly attractive. This paper will review reusable platform concepts and will discuss their range of application. Particular emphasis will be placed on technical limitations. Traditional concepts as jackups and floating production facilities will be discussed by major attention will be given to newly developed ideas for reuse of steel jackets and concrete structures. It will be shown how the operator for several fields can obtain considerable savings by applying such reusable platform concepts

  2. Outsourcing. The Concept

    Directory of Open Access Journals (Sweden)

    Victor-Adrian TROACĂ

    2012-06-01

    Full Text Available In the last two decades, an economic phenomenon took place, phenomenon characterized by the transfer of manufacturing activity from the developed countries to those in developing process. This practice can be considered as the response found by the large companies to the problem of production costs that were in a continuous rising, concomitant with the rising of living standards and remuneration.This paper aims to analyze the concept of outsourcing in terms of its evolution, but also in terms of incentives, ups and downs associated with the concept. On the other hand, this paper seeks to capture the fundamentals of this concept veracity and whether it could be implemented in the public service.

  3. Communication, concepts and grounding.

    Science.gov (United States)

    van der Velde, Frank

    2015-02-01

    This article discusses the relation between communication and conceptual grounding. In the brain, neurons, circuits and brain areas are involved in the representation of a concept, grounding it in perception and action. In terms of grounding we can distinguish between communication within the brain and communication between humans or between humans and machines. In the first form of communication, a concept is activated by sensory input. Due to grounding, the information provided by this communication is not just determined by the sensory input but also by the outgoing connection structure of the conceptual representation, which is based on previous experiences and actions. The second form of communication, that between humans or between humans and machines, is influenced by the first form. In particular, a more successful interpersonal communication might require forms of situated cognition and interaction in which the entire representations of grounded concepts are involved. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Designing concepts and strategies

    DEFF Research Database (Denmark)

    Kiib, Hans

    2012-01-01

    , that new developments often employ very modest research on the subject and often very little has been done in order to challenge traditional concepts and to invent new sustainable concepts for redevelopment. In order to avoid mistakes in urban redevelopment we need to learn from research and evaluation...... of the best planning practice. But what might be just as important is to learn from concept development practice, which can give us a comprehensive understanding of our complex cities and make us develop a way of experiencing the unique qualities of the architectural typologies at the site. Finally...... and strategies are briefly described in the article, and the adaption by city planners and developers has been critical reviewed....

  5. The hue of concepts.

    Science.gov (United States)

    Albertazzi, Liliana; Canal, Luisa; Malfatti, Michela; Micciolo, Rocco

    2013-01-01

    The study shows a systematic naturally biased association between percepts and concepts. Specifically, it shows that a series of terms pertaining to an abstract semantic field (related to the frame of ethics in social behaviour) has a nonrandom, highly significant, association with colours (hues). This is the first time that consistent associations between abstract terms and colours have been reported in the general population. The main hypothesis, ie that there appear to be 'hues of concepts', was borne out by the results: the abstract terms considered were coloured with blue/green (ie cool) colours as well as their synonyms, while their antonyms were coloured with red/yellow (ie warm) colours. The association provides information about the nature of abstract concepts and their relationship with perception. It also sheds light on the interrelations among words in semantic domains that, to date, have been studied from only a computational viewpoint.

  6. Concepts in catalysis

    International Nuclear Information System (INIS)

    Boudart, M.

    1992-01-01

    This paper reports on concept in catalysis which are very important in heterogeneous catalysis, even today, when in spite of surface science, the complexity of events at a real catalytic surface is still evading the understanding necessary for design. In this paper the authors will attempt to give an update on evolving concepts in heterogeneous catalysis. The topics include: counting active centers on metal surfaces; the notion of turnover frequency for a catalytic cycle; the concept of structure (in) sensitive reactions; the ensemble (geometric) vs. The ligand (electronic) effect following Sachtler's school; the idea of a rate determining step and of a most abundant reactive intermediate; the effect of surface non-uniformity on catalytic kinetics; what makes catalytic cycles turnover

  7. Systemizing the Pedagogic Concepts

    Directory of Open Access Journals (Sweden)

    G. N. Serikov

    2013-01-01

    Full Text Available The paper emphasizes the necessity of systemizing the pedagogic concepts to complement the pluralism principle dominating in pedagogy over the recent years. The author recommends the person oriented systematic synergetic methodology combining various research data into a holistic scientific approach. The paper regards education as the core pedagogic concept - including training, upbringing, self-education, their respective subcomponents, and generated personal resource. The elements of personal resource combine the acquired knowledge, skills and values, developed subjective attitudes and individual health data. The key pedagogic terms describing the educational process are represented by a three-level system; the first level involves the educational form concepts, the second – generated personal resource, the third – summarized notion system combining the previous levels and reflecting their binary relations. The given construct systemizes the pedagogic conceptual apparatus and clarifies the theoretical notion of personal education. 

  8. Introduction: Bridging Concepts.

    Science.gov (United States)

    Davids, Karel

    2015-12-01

    How can those in the history of science, history of technology, and economics communicate more with each other than they are accustomed? How can they become more globally oriented? While these three disciplines today have more convergent interests than in the past, there is still a large potential for further exchange and involvement to explore and exploit. The contributors to this Focus section discuss a number of concepts that may serve as tools to bring these three disciplines more closely together and ease their evolution in a less Eurocentric direction. These concepts include trading zones, interaction and formalization, production, and machines and self-organization.

  9. CONCEPT-5 user's manual

    International Nuclear Information System (INIS)

    Hudson, C.R. II.

    1979-01-01

    The CONCEPT computer code package was developed to provide conceptual capital cost estimates for nuclear-fueled and fossil-fired power plants. Cost estimates can be made as a function of plant type, size, location, and date of initial operation. The output includes a detailed breakdown of the estimate into direct and indirect costs similar to the accounting system described in document NUS--531. Cost models are currently provided in CONCEPT 5 for single- and multiunit pressurized-water reactors, boiling-water reactors, and cost-fired plants with and without flue gas desulfurization equipment

  10. Concepts of quantum optics

    CERN Document Server

    Knight, P L

    1983-01-01

    Concepts of Quantum Optics is a coherent and sequential coverage of some real insight into quantum physics. This book is divided into six chapters, and begins with an overview of the principles and concepts of radiation and quanta, with an emphasis on the significance of the Maxwell's electromagnetic theory of light. The next chapter describes first the properties of the radiation field in a bounded cavity, showing how each cavity field mode has the characteristics of a simple harmonic oscillator and how each can be quantized using known results for the quantum harmonic oscillator. This chapte

  11. Loneliness: a concept analysis.

    Science.gov (United States)

    Bekhet, Abir K; Zauszniewski, Jaclene A; Nakhla, Wagdy E

    2008-01-01

    Loneliness is a universal human experience recognized since the dawn of time, yet it is unique for every individual. Loneliness can lead to both depression and low self-esteem. This article explicates the concept of loneliness through the examination of its conceptual definition and uses, defining attributes, related concepts, and empirical referents. Literature review using hand search and database were used as sources of information. Because loneliness is commonly encountered in nursing situations, the information provided will serve as a framework for assessment, planning, intervention, and evaluation of clients.

  12. Stress: a concept analysis.

    Science.gov (United States)

    Goodnite, Patricia M

    2014-01-01

    To analyze the concept of stress and provide an operational definition of stress. Literature review revealed that stress is a commonly used, but often ambiguous, term. Findings supported a definition of stress entailing an individual's perception of a stimulus as overwhelming, which in turn elicits a measurable response resulting in a transformed state. This analysis adopts a dynamic definition of stress that may serve to encourage communication, promote reflection, and enhance concept understanding. This definition may provide direction for future work, as well as enhance efforts to serve patients affected by stress. © 2013 Wiley Periodicals, Inc.

  13. Tokamak concept innovations

    International Nuclear Information System (INIS)

    1986-04-01

    This document contains the results of the IAEA Specialists' Meeting on Tokamak Concept Innovations held 13-17 January 1986 in Vienna. Although it is the most advanced fusion reactor concept the tokamak is not without its problems. Most of these problems should be solved within the ongoing R and D studies for the next generation of tokamaks. Emphasis for this meeting was placed on innovations that would lead to substantial improvements in a tokamak reactor, even if they involved a radical departure from present thinking

  14. Wind farm radar study

    International Nuclear Information System (INIS)

    Davies, N.G.

    1995-01-01

    This report examines the possible degradations of radar performance that may be caused by the presence of a wind turbine generator within the radar coverage area. A brief literature survey reviews the previously published work, which is mainly concerned with degradation of broadcast TV reception. Estimates are made of wind turbine generator scattering cross-sections, and of the time and Doppler characteristics of the echo signals from representative wind turbine generator. The general characteristics of radar detection and tracking methods are described, and the behaviour of such systems in the presence of strong returns from a wind turbine generator (or an array of them) is discussed. (author)

  15. Innatism, Concept Formation, Concept Mastery and Formal Education

    Science.gov (United States)

    Winch, Christopher

    2015-01-01

    This article will consider the claim that the possession of concepts is innate rather than learned. Innatism about concept learning is explained through consideration of the work of Fodor and Chomsky. First, an account of concept formation is developed. Second the argument against the claim that concepts are learned through the construction of a…

  16. THE EFFECT OF CONCEPT MAPPING ON CONCEPT LEARNING IN SCIENCE

    OpenAIRE

    岡, 直樹; 今永, 久美子

    2012-01-01

    An experiment was conducted to investigate the effects of concept map completion tasks on concept learning in the primary schoolchildren. The participants were to insert some of the suitable concepts (concept group) or link labeles (link label group) or both of them (concept/link label group) into the blanks to make up the map wholly. It was revealed that the results of the concept group and the concept/link label group were better than the link label group. These results were discussed in te...

  17. New detector concepts

    International Nuclear Information System (INIS)

    Kemmer, J.; Lutz, G.

    1986-07-01

    On the basis of the semiconductor drift chamber many new detectors are proposed, which enable the determination of energy, energy loss, position and penetration depth of radiation. A novel integrated transistor-detector configuration allows non destructive repeated readout and amplification of the signal. The concept may be used for the construction of one or two-dimensional PIXEL arrays. (orig.)

  18. Liquid fuel concept benefits

    International Nuclear Information System (INIS)

    Hron, M.

    1996-01-01

    There are principle drawbacks of any kind of solid nuclear fuel listed and analyzed in the first part of the paper. One of the primary results of the analyses performed shows that the solid fuel concept, which was to certain degree advantageous in the first periods of a nuclear reactor development and operation, has guided this branch of a utilization of atomic nucleus energy to a death end. On the background of this, the liquid fuel concept and its benefits are introduced and briefly described in the first part of the paper, too. As one of the first realistic attempts to utilize the advantages of liquid fuels, the reactor/blanket system with molten fluoride salts in the role of fuel and coolant simultaneously, as incorporated in the accelerator-driven transmutation technology (ADTT) being proposed and currently having been under development in the Los Alamos National Laboratory, will be studied both theoretically and experimentally. There is a preliminary design concept of an experimental assembly LA-O briefly introduced in the paper which is under preparation in the Czech Republic for such a project. Finally, there will be another very promising concept of a small low power ADTT system introduced which is characterized by a high level of safety and economical efficiency. In the conclusion, the overall survey of principal benefits which may be expected by introducing liquid nuclear fuel in nuclear power and research reactor systems is given and critically analyzed. 7 refs, 4 figs

  19. CONCEPT OF MOBILE LEARNING

    Directory of Open Access Journals (Sweden)

    Г О Дуйсеева

    2016-12-01

    Full Text Available This article deals with the definition and the description of mobile learning. Ten years’ experience of the latest mobile technologies use and devices in educational process abroad is analyzed. Prospects and the possibilities of application of these technologies are considered. The basic concepts and development of mobile learning which proposed by scientists for the last years have been given.

  20. [Self esteem : concept analysis.

    Science.gov (United States)

    Doré, Christina

    2017-06-01

    Self-esteem is an inner attitude at the base of the construction of personality and psychic balance in addition to be responsible of adaptive processes over the course of life. The concept of self-esteem is commonly used in several disciplines however, it seems that the consensus on its conceptualization and its operationalization is not yet reached. In this context, the concept analysis allows to address a phenomenon and to understand its use and its evolution from a unique disciplinary perspective. The aim of this article is therefore to analyze the concept of self esteem from a nursing perspective to identify : definitions of the term and related terms, attributes, model and limit cases proposed here within the community of mental health nurses, antecedents and consequents as well as the empirical references using the Walker and Avant method. The attributes identified allowing a deeper understanding of the concept are : the self-value, the self-acceptance, the self-efficacy, attitude towards oneself and finally, self-respect.

  1. Communication, concepts and grounding

    NARCIS (Netherlands)

    van der Velde, Frank; van der Velde, F.

    2015-01-01

    This article discusses the relation between communication and conceptual grounding. In the brain, neurons, circuits and brain areas are involved in the representation of a concept, grounding it in perception and action. In terms of grounding we can distinguish between communication within the brain

  2. Thirdness and psychoanalytic concepts.

    Science.gov (United States)

    Green, André

    2004-01-01

    Many psychoanalytic concepts lend themselves to the notion of thirdness. Starting from a basis of Freudian thought, the author discusses some of the elaborative contributions of Winnicott, Lacan, and Bion, as well as the ideas of Saussure and Peirce, noting how all these incorporate an appreciation of the value and relevance of thirdness in both the theory and practice of psychoanalysis.

  3. Elaborating on Threshold Concepts

    Science.gov (United States)

    Rountree, Janet; Robins, Anthony; Rountree, Nathan

    2013-01-01

    We propose an expanded definition of Threshold Concepts (TCs) that requires the successful acquisition and internalisation not only of knowledge, but also its practical elaboration in the domains of applied strategies and mental models. This richer definition allows us to clarify the relationship between TCs and Fundamental Ideas, and to account…

  4. Two Conceptions of Virtue

    Science.gov (United States)

    Hill, Thomas E., Jr.

    2013-01-01

    The general questions are: what is virtue and how can it be cultivated? The specific focus is on the conceptions of virtue in the works of Immanuel Kant and John Rawls. Kant regarded virtue as a good will that is also strong enough to resist contrary passions, impulses, and inclinations. Childhood training can prepare children for virtue, but…

  5. Some Core Contested Concepts

    Science.gov (United States)

    Chomsky, Noam

    2015-01-01

    Core concepts of language are highly contested. In some cases this is legitimate: real empirical and conceptual issues arise. In other cases, it seems that controversies are based on misunderstanding. A number of crucial cases are reviewed, and an approach to language is outlined that appears to have strong conceptual and empirical motivation, and…

  6. Sound Search Engine Concept

    DEFF Research Database (Denmark)

    2006-01-01

    Sound search is provided by the major search engines, however, indexing is text based, not sound based. We will establish a dedicated sound search services with based on sound feature indexing. The current demo shows the concept of the sound search engine. The first engine will be realased June...

  7. The LDC detector concept

    Indian Academy of Sciences (India)

    Abstract. In preparation of the experimental program at the international linear collider (ILC), the large detector concept (LDC) is being developed. The main points of the LDC are a large volume gaseous tracking system, combined with high precision vertex detector and an extremely granular calorimeter. The main design ...

  8. Innovative transparent armour concepts

    NARCIS (Netherlands)

    Carton, E.P.; Broos, J.P.F.

    2011-01-01

    Ever since WWII transparent armour consists of a multi-layer of glass panels bonded by thin polymer bond-films using an autoclave process. TNO has worked on the development of innovative transparent armour concepts that are lighter and a have better multi-hit capacity. Two new transparent armour

  9. Mengembangkan Self Concept Siswa Melalui Model Pembelajaran Concept Attainment

    OpenAIRE

    Sumartini, Tina Sri

    2015-01-01

    Dalam pembelajaran matematika, siswa masih kurang memiliki self concept yang positif. Salah satu model pembelajaran yang dapat diterapkan untuk mengembangkan self concept siswa adalah model concept attainment. Tujuan penelitian ini adalah untuk mengetahui perkembangan self concept siswa setelah mendapatkan model pembelajaran concept attainment. Penelitian ini berbentuk one shot case study. Populasi dalam penelitian ini adalah siswa di salah satu SMK di Kabupaten Garut. Pengambilan sampel d...

  10. Two Concepts of Rationality

    Directory of Open Access Journals (Sweden)

    Danny Frederick

    2010-02-01

    Full Text Available The dominant tradition in Western philosophy sees rationality as dictating. Thus rationality may require that we believe the best explanation and simple conceptual truths and that we infer in accordance with evident rules of inference. I argue that, given what we know about the growth of knowledge, this authoritarian concept of rationality leads to absurdities and should be abandoned. I then outline a libertarian concept of rationality, derived from Popper, which eschews the dictates and which sees a rational agent as one who questions, criticises, conjectures and experiments. I argue that, while the libertarian approach escapes the absurdities of the authoritarian, it requires two significant developments and an important clarification to be made fully consistent with itself.

  11. Concepts in Thermal Physics

    CERN Document Server

    Blundell, Stephen J

    2006-01-01

    This modern introduction to thermal physics contains a step-by-step presentation of the key concepts. The text is copiously illustrated and each chapter contains several worked examples. - ;An understanding of thermal physics is crucial to much of modern physics, chemistry and engineering. This book provides a modern introduction to the main principles that are foundational to thermal physics, thermodynamics, and statistical mechanics. The key concepts are carefully presented in a clear way, and new ideas are illustrated with copious worked examples as well as a description of the historical background to their discovery. Applications are presented to subjects as. diverse as stellar astrophysics, information and communication theory, condensed matter physics, and climate change. Each chapter concludes with detailed exercises. -

  12. Hybrid system concepts

    International Nuclear Information System (INIS)

    Landeyro, P.A.

    1995-01-01

    Hybrid systems studied for fissile material production, were reconsidered for minor actinide and long-lived fission product destruction as alternative to the traditional final disposal of nuclear waste. Now there are attempts to extend the use of the concepts developed for minor actinide incineration to plutonium burning. The most promising hybrid system concept considers fuel and target both as liquids. From the results obtained, the possibility to adopt composite targets seems the most promising solution, but still there remains the problem of Pu production, not acceptable in a burning system. This kind of targets can be mainly used for fissile material production, while for accelerator driven burners it is most convenient to use a liquid lead target. The most suitable solvent is heavy water for minor actinide annihilation in the blanket of a hybrid system. Due to the criticality conditions and the necessity of electric energy production, the blanket using plutonium dissolved in molten salts is the most convenient one. (author)

  13. Three concepts of history

    Directory of Open Access Journals (Sweden)

    Antonio Campillo

    2016-05-01

    Full Text Available The aim of this article is twofold. On the one hand, I will outline the diverse usages that the concept of history has taken on throughout Western history. These different usages may be grouped together in three semantic fields (history as a way of knowing, as a way of being and as a way of doing, which correspond to three ways of understanding the Philosophy of History: as Epistemology of History, as Ontology of historicity and as ethical-political Critique of the present. On the other hand, I will show that these three concepts of history (and, accordingly, the three ways of understanding the Philosophy of History refer mutually to each other and, thus, are inseparable from each other.

  14. Concepts of intrinsic safety

    International Nuclear Information System (INIS)

    Anon.

    1985-01-01

    A newly introduced Japanese reactor concept, ISER (Intrinsically Safe and Economical Reactor), is intended to be a reference intrinsically safe light water reactor. ISER is designed similarly to PIUS but with greater economy in mind such that any utility in any country can choose it for its power system. Social assimilation and acceptability in the Asia Pacific Region including the United States are the keys to the ISER with the hope of dramatic reductions of social costs due to safeguards, reliability, financiability, and infrastructure building, particularly in the third world, as well as reactor safety itself. In this respect and others, the ISER proposal is different from other vendor-proposed reactor concepts and is unique

  15. TQM: the essential concepts.

    Science.gov (United States)

    Chambers, D W

    1998-01-01

    This is an introduction to the major concepts in total quality management, a loose collection of management approaches that focus on continuous improvement of processes, guided by routine data collection and adjustment of the processes. Customer focus and involvement of all members of an organization are also characteristics commonly found in TQM. The seventy-five-year history of the movement is sketched from its beginning in statistical work on quality assurance through the many improvements and redefinitions added by American and Japanese thinkers. Essential concepts covered include: control cycles, focus on the process rather than the defects, the GEAR model, importance of the customer, upstream quality, just-in-time, kaizen, and service quality.

  16. Dual coolant blanket concept

    International Nuclear Information System (INIS)

    Malang, S.; Schleisiek, K.

    1994-11-01

    A self-cooled liquid metal breeder blanket with helium-cooled first wall ('Dual Coolant Blanket Concept') for a fusion DEMO reactor is described. This is one of the four blanket concepts under development in the frame of the European fusion technology program with the aim to select in 1995 the two most promising ones for further development. Described are the design of the blankets including the ancillary loop system and the results of the theoretical and experimental work in the fields of neutronics, magnetohydrodynamics, thermohydraulics, mechanical stresses, compatibility and purification of lead-lithium, tritium control, safety, reliability, and electrically insulating coatings. The remaining open questions and the required R and D programme are identified. (orig.) [de

  17. Conception of Brownian coil

    OpenAIRE

    Zhang, Jiayuan

    2018-01-01

    This article proposes a conception of Brownian coil. Brownian coil is a tiny coil with the same size of pollen. Once immersed into designed magnetic field and liquid, the coil will be moved and deformed macroscopically, due to the microscopic thermodynamic molecular collisions. Such deformation and movement will change the magnetic flux through the coil, by which an ElectroMotive Force (EMF) is produced. In this work, Brownian heat exchanger and Brownian generator are further designed to tran...

  18. Some core contested concepts.

    Science.gov (United States)

    Chomsky, Noam

    2015-02-01

    Core concepts of language are highly contested. In some cases this is legitimate: real empirical and conceptual issues arise. In other cases, it seems that controversies are based on misunderstanding. A number of crucial cases are reviewed, and an approach to language is outlined that appears to have strong conceptual and empirical motivation, and to lead to conclusions about a number of significant issues that differ from some conventional beliefs.

  19. The Seismographic Design Concept

    DEFF Research Database (Denmark)

    Salamon, Karen Lisa; Engholm, Ida

    2015-01-01

    This article gives an overview of the theoretical development of the design concept through two centuries in Europe and North America. Drawing on the academic disciplines of design history and anthropology, the authors present seminal moments in the theorization of “design”. Historically formativ...... argues for a more historically reflective glance on theory’s influence on the moulding of practice from ideology also in the context of design, and presents itself as a step in this self reflective direction....

  20. CONCEPT ANALYSIS: AGGRESSION

    OpenAIRE

    Liu, Jianghong

    2004-01-01

    The concept of aggression is important to nursing because further knowledge of aggression can help generate a better theoretical model to drive more effective intervention and prevention approaches. This paper outlines a conceptual analysis of aggression. First, the different forms of aggression are reviewed, including the clinical classification and the stimulus-based classification. Then the manifestations and measurement of aggression are described. Finally, the causes and consequences of ...

  1. Basic concepts in oceanography

    International Nuclear Information System (INIS)

    Small, L.F.

    1997-01-01

    Basic concepts in oceanography include major wind patterns that drive ocean currents, and the effects that the earth's rotation, positions of land masses, and temperature and salinity have on oceanic circulation and hence global distribution of radioactivity. Special attention is given to coastal and near-coastal processes such as upwelling, tidal effects, and small-scale processes, as radionuclide distributions are currently most associated with coastal regions. (author)

  2. Fundamental concepts on energy

    International Nuclear Information System (INIS)

    Rodriguez, M.H.

    1998-01-01

    The fundamental concepts on energy and the different forms in which it is manifested are presented. Since it is possible to transform energy in a way to other, the laws that govern these transformations are discussed. The energy transformation processes are an essential compound in the capacity humanizes to survive and be developed. The energy use brings important economic aspects, technical and political. Because this, any decision to administer energy system will be key for our future life

  3. Resilience - A Concept

    Science.gov (United States)

    2016-04-05

    the assessment of the health of a network or system. The hypothesis is: resiliency is meaningful in the context of holistic assessments of... health , holistic , Resiliency Tier, Resiliency Tier Matrix, State of Resiliency 295Defense ARJ, July 2015, Vol. 22 No. 3 : 294–324 296 Defense ARJ, July...upon who is speaking. Taking this one step further, consider resiliency as a concept that provides a holistic view of a system or capability, just

  4. Molten salt reactor concept

    International Nuclear Information System (INIS)

    Sood, D.D.

    1980-01-01

    Molten salt reactor is an advanced breeder concept which is suited for the utilization of thorium for nuclear power production. This reactor is based on the use of solutions of uranium or plutonium fluorides in LiF-BeF 2 -ThF 4 as fuel. Unlike the conventional reactors, no external coolant is used in the reactor core and the fuel salt itself is circulated through heat exchangers to transfer the fission produced heat to a secondary salt (NaF-NaBF 4 ) for steam generation. A part of the fuel stream is continuously processed to isolate 233 Pa, so that it can decay to fissile 233 U without getting converted to 234 Pa, and for the removal of neutron absorbing fission products. This on-line processing scheme makes this reactor concept to achieve a breeding ratio of 1.07 which is the highest for any thermal breeder reactor. Experimental studies at the Bhabha Atomic Research Centre, Bombay, have established the use of plutonium as fuel for this reactor. This molten salt reactor concept is described and the work conducted at the Bhabha Atomic Research Centre is summarised. (auth.)

  5. Four concepts of Africa

    Directory of Open Access Journals (Sweden)

    Willem Fourie

    2015-05-01

    Full Text Available What makes the words ‘Africa’ and ‘African’ possible and useful? In this article it is argued that at least four internally coherent concepts of Africa exist, and that none of these concepts are ethically neutral. The article is presented as a contribution to attempts at using the term ‘Africa’ in self-critical, reflexive and constructive ways. It could therefore be of interest to all researchers, particularly those in the humanities and theology, who locate their research within the context of ‘Africa’. It is argued that Africa can be conceived of as a place, a commodity, a condition and an ideal. By drawing on mostly primary sources it is shown that the term ‘Africa’ only relatively recently came to refer to a continent, that Africa as a place and Africa as a condition in need of betterment formed the foundation for its commodification, and that Africa only very recently became a self-description of the people who live on the continent of Africa. Each of these concepts of Africa is shown to be based on a particular logic with both strengths and weaknesses.

  6. SCWR Concept in Korea

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2014-08-15

    One of the major difficulties in the design of an SCWR is the additional neutron moderation in order to compensate the low coolant density in the later stage of coolant heat-up. The water rod concept was introduced as a simple method to provide additional moderation, however it may result in an inevitable complexity in the design of the reactor upper part. A solid moderator concept was introduced in the Korean SCWR to avoid this difficulty. A conceptual design of a 1400 MWe SCWR core with a cruciform type of U/ZrH{sub 2} solid moderator has been studied. The design features include a solid moderator design, an axial zoning of the burnable poison and fuel rod, a flow rate control by adjusting the orifice design, and a control rod design for an excess reactivity control. The maximum power peaking is 2.48 and the maximum coolant temperature is 577°C. Reactivity coefficients such as the moderator temperature coefficient and fuel temperature coefficient are negative for the whole burn-up period. At a cold zero power condition, the minimum shutdown margin is 1.16%Δρ at the beginning of a cycle, which satisfies the required shutdown margin limit. The concept described here should not be considered as a complete one, but a preliminary idea. It is solely based on information frozen at the time, and is subject to further improvement.

  7. Space Mission Concept Development Using Concept Maturity Levels

    Science.gov (United States)

    Wessen, Randii R.; Borden, Chester; Ziemer, John; Kwok, Johnny

    2013-01-01

    Over the past five years, pre-project formulation experts at the Jet Propulsion Laboratory (JPL) has developed and implemented a method for measuring and communicating the maturity of space mission concepts. Mission concept development teams use this method, and associated tools, prior to concepts entering their Formulation Phases (Phase A/B). The organizing structure is Concept Maturity Level (CML), which is a classification system for characterizing the various levels of a concept's maturity. The key strength of CMLs is the ability to evolve mission concepts guided by an incremental set of assessment needs. The CML definitions have been expanded into a matrix form to identify the breadth and depth of analysis needed for a concept to reach a specific level of maturity. This matrix enables improved assessment and communication by addressing the fundamental dimensions (e.g., science objectives, mission design, technical risk, project organization, cost, export compliance, etc.) associated with mission concept evolution. JPL's collaborative engineering, dedicated concept development, and proposal teams all use these and other CML-appropriate design tools to advance their mission concept designs. This paper focuses on mission concept's early Pre-Phase A represented by CMLs 1- 4. The scope was limited due to the fact that CMLs 5 and 6 are already well defined based on the requirements documented in specific Announcement of Opportunities (AO) and Concept Study Report (CSR) guidelines, respectively, for competitive missions; and by NASA's Procedural Requirements NPR 7120.5E document for Projects in their Formulation Phase.

  8. Self-Concept Is a Concept Worth Considering

    Science.gov (United States)

    Shields, Nora

    2009-01-01

    There is a growing recognition of the importance of self-concept in the pediatric rehabilitation research literature. There also is confusion and inconsistency in the definitions of and the terminology used to describe self-concept. What is agreed is that self-concept is multidimensional, comprising a child's perception of their personal…

  9. Concept caring in nursing

    Directory of Open Access Journals (Sweden)

    Lenka Drahošová

    2016-05-01

    Full Text Available Aim: The aim of this literature review was to search for qualitative studies focusing on the concept of caring in nursing, to analyse them and to synthesize knowledge that concerns the definition of the concept of caring in nursing from the point of view of nurses and patients. Design: Review. Methods: Qualitative studies were searched for systematically in the electronic databases Academic Search Complete (EBSCO, CINAHL, Medline, Science Direct, and the Wiley Library Online, according to set criteria and defined key words for the period 1970-2015. Seven selected articles were analysed after selection of documents with the aid of a sorting chart. Results: Nurses understand caring in nursing as a relationship with patients which is characterised on the nurses' part by an individual and empathetic approach, attentiveness, experience and sensitivity. Through caring, active communication takes place, providing information which reduces anxiety and leads to the breaking down of barriers. This relationship helps protect patients' autonomy, dignity and comfort. It requires experience on the part of nurses, and it is influenced by the environment. The nurses' personal qualities (what professional knowledge, attitudes and skills they have and their availability, reliability, and emotional and physical support are important to patients. Conclusion: The concept of caring is a content specific interpersonal process which is characterized by the professional knowledge, skills, personal maturity, and interpersonal sensitivity of nurses, which result in the protection, emotional support, and the meeting of bio-psycho-social needs of patients. The results of the overview study could contribute to an explanation and understanding of the nature of caring as a fundamental feature of the discipline of nursing.

  10. SCWR Concepts in Japan

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2014-08-15

    Two SCWR concepts are being developed in Japan, one corresponding to the thermal spectrum reactor and the other to the fast spectrum reactor. Yamada et al. described the thermal-spectrum reactor concept referred to as the Japan SCWR (or JSCWR). This concept was developed under the financial support of the Ministry of Economy, Trade and Industry (METI). The basic philosophy of the JSCWR development is to utilize proven light water reactor and supercritical fossil-fired power plant technologies as much as possible to minimize the R&D cost, time and risks. Therefore, the JSCWR is designed as a thermal neutron spectrum reactor using light water as moderator and reactor coolant. The JSCWR plant consists of a pressure-vessel type, once-through reactor and a direct Rankine cycle system. Reactor coolant fed through inlet nozzles is heated up in the core and flows through outlet nozzles with no recirculation in the vessel. Other options to the JSCWR core design are being investigated at the University of Tokyo. The electric output of the JSCWR is assumed to range from 600 MWe to 1700 MWe class to fulfill user’s requirements as much as possible. In this section, the reference value is selected to 1725 MWe, which corresponds to a reactor thermal output of 4039 MWth. Nakatsuka et al. described the core design for the fast-spectrum reactor, which is based on a similar plant system compared to that of the thermal-spectrum reactor. The fast-spectrum reactor, however, would produce higher power rating than the thermal-spectrum one of the same reactor pressure-vessel size. Since the fast-spectrum reactor does not require the moderator, its unit capital cost would be lower than the thermal-spectrum reactor.

  11. Concepts of modern mathematics

    CERN Document Server

    Stewart, Ian

    1995-01-01

    Some years ago, ""new math"" took the country's classrooms by storm. Based on the abstract, general style of mathematical exposition favored by research mathematicians, its goal was to teach students not just to manipulate numbers and formulas, but to grasp the underlying mathematical concepts. The result, at least at first, was a great deal of confusion among teachers, students, and parents. Since then, the negative aspects of ""new math"" have been eliminated and its positive elements assimilated into classroom instruction.In this charming volume, a noted English mathematician uses humor an

  12. Concepts of combinatorial optimization

    CERN Document Server

    Paschos, Vangelis Th

    2014-01-01

    Combinatorial optimization is a multidisciplinary scientific area, lying in the interface of three major scientific domains: mathematics, theoretical computer science and management.  The three volumes of the Combinatorial Optimization series aim to cover a wide range  of topics in this area. These topics also deal with fundamental notions and approaches as with several classical applications of combinatorial optimization.Concepts of Combinatorial Optimization, is divided into three parts:- On the complexity of combinatorial optimization problems, presenting basics about worst-case and randomi

  13. The concept of probability

    International Nuclear Information System (INIS)

    Bitsakis, E.I.; Nicolaides, C.A.

    1989-01-01

    The concept of probability is now, and always has been, central to the debate on the interpretation of quantum mechanics. Furthermore, probability permeates all of science, as well as our every day life. The papers included in this volume, written by leading proponents of the ideas expressed, embrace a broad spectrum of thought and results: mathematical, physical epistemological, and experimental, both specific and general. The contributions are arranged in parts under the following headings: Following Schroedinger's thoughts; Probability and quantum mechanics; Aspects of the arguments on nonlocality; Bell's theorem and EPR correlations; Real or Gedanken experiments and their interpretation; Questions about irreversibility and stochasticity; and Epistemology, interpretation and culture. (author). refs.; figs.; tabs

  14. Simulation - Concepts and Applications

    Science.gov (United States)

    Silva, Pedro Sá; Trigo, António; Varajão, João; Pinto, Tiago

    Simulation in last decades has been widely used to analyze the impact of different scenarios in several areas like, for instance, health, military, business, and many others. When well used, it is an excellent tool to analyze alternative actions and to anticipate their impact, in order to rationalize the spending of resources. This paper introduces and resumes some of the main concepts of simulation, identifying and describing: systems; models; entities and attributes; resources; contexts of use; and, in particularly, the discrete-event simulation.

  15. On the Probabilty Concept

    Directory of Open Access Journals (Sweden)

    Bruno De Finetti

    2016-09-01

    Full Text Available As it has been already done for the Corrado Gini's works, STATISTICA has accepted the invitation of some researchers who asked to republish the English translation of some fundamental De Finetti's papers. These works were translated into English and published in the volume: Bruno De Finetti, Induction and Probability, Biblioteca di Statistica, eds. P. Monari, D. Cocchi, Clueb, Bologna, 1993. On the Probability Concept is one of the first fundamental philosophical papers in which we can find the essential basis of De Finetti's subjective approach to the Theory of probability.

  16. CONCEPT computer code

    International Nuclear Information System (INIS)

    Delene, J.

    1984-01-01

    CONCEPT is a computer code that will provide conceptual capital investment cost estimates for nuclear and coal-fired power plants. The code can develop an estimate for construction at any point in time. Any unit size within the range of about 400 to 1300 MW electric may be selected. Any of 23 reference site locations across the United States and Canada may be selected. PWR, BWR, and coal-fired plants burning high-sulfur and low-sulfur coal can be estimated. Multiple-unit plants can be estimated. Costs due to escalation/inflation and interest during construction are calculated

  17. Pediatric obesity: Current concepts.

    Science.gov (United States)

    Greydanus, Donald E; Agana, Marisha; Kamboj, Manmohan K; Shebrain, Saad; Soares, Neelkamal; Eke, Ransome; Patel, Dilip R

    2018-04-01

    This discussion reflects on concepts of obesity in children and adolescents in the early 21st century. It includes reflections on its history, definition, epidemiology, diagnostic perspectives, psychosocial considerations, musculoskeletal complications, endocrine complications and principles of management. In addition to emphasis on diet and exercise, research and clinical applications in the second decade of the 21 st century emphasize the increasing use of pharmacotherapy and bariatric surgery for adolescent and adult populations with critical problems of overweight and obesity. We conclude with a discussion of future directions in pediatric obesity management. Copyright © 2018 Mosby, Inc. All rights reserved.

  18. Advanced divertor concepts

    International Nuclear Information System (INIS)

    Ohyabu, N.; Komori, A.; Sagara, A.; Suzuki, H.; Morisaki, T.; Masuzaki, S.; Watanabe, T.; Noda, N.; Motojima, O.

    1996-01-01

    LHD divertor development program has generated various innovative divertor concepts and technologies which will help to improve the plasma performance in both helical and tokamak devices. They are two divertor operational scenarios (confinement improvement by generating high temperature divertor plasma and simultaneous achievement of radiative cooling and H-mode-like confinement improvement). Local island divertor geometry has also been proposed. This new divertor has been successfully tested in the CHS device and is planned to be installed in the LHD device. In addition, technological development of new efficient hydrogen pumping schemes (carbon sheet pump and membrane pump) are being pursued for enhancement of the divertor control capability. 17 refs., 8 figs

  19. Concepts of electrodynamics

    CERN Document Server

    Kumar, Vinay

    2016-01-01

    The present book entitled Concepts of Electrodynamics meets the demand of students of all engineering, graduate, honours and postgraduate courses in a single volume. This book covers all the topics on electrodynamics as per the new syllabus prescribed by UGC and AICTE and we do hope that this book will revive interest in the study of various topics on electrodynamics which will carries the reader to a high level of understanding. The text is enriched with a large number of solved examples apart from appropriate illustrations and examples in each chapter.

  20. Indian concepts on sexuality.

    Science.gov (United States)

    Chakraborty, Kaustav; Thakurata, Rajarshi Guha

    2013-01-01

    India is a vast country depicting wide social, cultural and sexual variations. Indian concept of sexuality has evolved over time and has been immensely influenced by various rulers and religions. Indian sexuality is manifested in our attire, behavior, recreation, literature, sculptures, scriptures, religion and sports. It has influenced the way we perceive our health, disease and device remedies for the same. In modern era, with rapid globalization the unique Indian sexuality is getting diffused. The time has come to rediscover ourselves in terms of sexuality to attain individual freedom and to reinvest our energy to social issues related to sexuality.

  1. Actuator concepts and mechatronics

    Science.gov (United States)

    Gilbert, Michael G.; Horner, Garnett C.

    1998-06-01

    Mechatronic design implies the consideration of integrated mechanical, electrical, and local control characteristics in electromechanical device design. In this paper, mechatronic development of actuation device concepts for active aircraft aerodynamic flow control are presented and discussed. The devices are intended to be embedded in aircraft aerodynamic surfaces to provide zero-net-momentum jets or additional flow-vorticity to control boundary layers and flow- separation. Two synthetic jet device prototypes and one vorticity-on-demand prototype currently in development are described in the paper. The aspects of actuation materials, design approaches to generating jets and vorticity, and the integration of miniaturized electronics are stressed.

  2. Anaxagoras concept of Nous

    OpenAIRE

    Gorgijev, Slađana

    2015-01-01

    When Ambrose, Anaxagoras have a theory of origin of the world, on whose head is immortal and eternal law Nous. Nous or cosmic mind, according to Anaxagoras is not the creator of the world but someone who plan governing the world, someone who runs the original seed and shapes. According to Anaxagoras original particles would be an amorphous material that was not Nous who has put in motion and thus introduced in order. The concept of Nous some philosophers understood as a mechanical principle a...

  3. Advanced microwave processing concepts

    Energy Technology Data Exchange (ETDEWEB)

    Lauf, R.J.; McMillan, A.D.; Paulauskas, F.L. [Oak Ridge National Laboratory, TN (United States)

    1995-05-01

    The purpose of this work is to explore the feasibility of several advanced microwave processing concepts to develop new energy-efficient materials and processes. The project includes two tasks: (1) commercialization of the variable-frequency microwave furnace; and (2) microwave curing of polymer composites. The variable frequency microwave furnace, whose initial conception and design was funded by the AIC Materials Program, will allow us, for the first time, to conduct microwave processing studies over a wide frequency range. This novel design uses a high-power traveling wave tube (TWT) originally developed for electronic warfare. By using this microwave source, one can not only select individual microwave frequencies for particular experiments, but also achieve uniform power densities over a large area by the superposition of many different frequencies. Microwave curing of thermoset resins will be studied because it hold the potential of in-situ curing of continuous-fiber composites for strong, lightweight components. Microwave heating can shorten curing times, provided issues of scaleup, uniformity, and thermal management can be adequately addressed.

  4. Concepts in surface physics

    CERN Document Server

    Desjonquères, M -C

    1993-01-01

    This textbook is intended as an introduction to surface science for graduate students. It began as a course of lectures that we gave at the University of Paris (Orsay). Its main objectives are twofold: to provide the reader with a compre­ hensive presentation of the basic principles and concepts of surface physics and to show the usefulness of these concepts in the real world by referring to experiments. It starts at a rather elementary level since it only requires a knowledge of solid state physics, quantum mechanics, thermodynamics and statistical physics which does not exceed the background usually taught to students early in their university courses. However, since it finally reaches an advanced level, we have tried to render it as self-contained as possible so that it remains accessible even to an unexperienced reader. Furthermore, the emphasis has been put on a pedagogical level rather than on a technical level. In this spirit, whenever possible, models which are simplified, but which contain the featu...

  5. ATR performance modeling concepts

    Science.gov (United States)

    Ross, Timothy D.; Baker, Hyatt B.; Nolan, Adam R.; McGinnis, Ryan E.; Paulson, Christopher R.

    2016-05-01

    Performance models are needed for automatic target recognition (ATR) development and use. ATRs consume sensor data and produce decisions about the scene observed. ATR performance models (APMs) on the other hand consume operating conditions (OCs) and produce probabilities about what the ATR will produce. APMs are needed for many modeling roles of many kinds of ATRs (each with different sensing modality and exploitation functionality combinations); moreover, there are different approaches to constructing the APMs. Therefore, although many APMs have been developed, there is rarely one that fits a particular need. Clarified APM concepts may allow us to recognize new uses of existing APMs and identify new APM technologies and components that better support coverage of the needed APMs. The concepts begin with thinking of ATRs as mapping OCs of the real scene (including the sensor data) to reports. An APM is then a mapping from explicit quantized OCs (represented with less resolution than the real OCs) and latent OC distributions to report distributions. The roles of APMs can be distinguished by the explicit OCs they consume. APMs used in simulations consume the true state that the ATR is attempting to report. APMs used online with the exploitation consume the sensor signal and derivatives, such as match scores. APMs used in sensor management consume neither of those, but estimate performance from other OCs. This paper will summarize the major building blocks for APMs, including knowledge sources, OC models, look-up tables, analytical and learned mappings, and tools for signal synthesis and exploitation.

  6. Borehole disposal design concept

    International Nuclear Information System (INIS)

    RANDRIAMAROLAHY, J.N.

    2007-01-01

    In Madagascar, the sealed radioactive sources are used in several socioeconomic sectors such as medicine, industry, research and agriculture. At the end of their useful lives, these radioactive sources become radioactive waste and can be still dangerous because they can cause harmful effects to the public and the environment. This work entitled 'Borehole disposal design concept' consists in putting in place a site of sure storage of the radioactive waste, in particular, sealed radioactive sources. Several technical aspects must be respected to carry out such a site like the geological, geomorphologic, hydrogeologic, geochemical, meteorological and demographic conditions. This type of storage is favorable for the developing countries because it is technologically simple and economic. The cost of construction depends on the volume of waste to store and the depth of the Borehole. The Borehole disposal concept provides a good level of safety to avoid the human intrusion. The future protection of the generations against the propagation of the radiations ionizing is then assured. [fr

  7. PRSEUS Structural Concept Development

    Science.gov (United States)

    Velicki, Alex; Jegley, Dawn

    2014-01-01

    A lighter, more robust airframe is one of the key technological advancements necessary for the successful launch of any large next-generation transport aircraft. Such a premise dictates that considerable improvements beyond current state-of-the-art aluminum structures is needed, and that improvements of this magnitude will require an extensive use of composite materials that are not only lightweight, but also economical to produce. To address this challenge, researchers at NASA and The Boeing Company are developing a novel structural concept called the Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) under the Environmentally Responsible Aviation (ERA) Project. It is an integrally stiffened panel concept that is stitched together and designed to maintain residual load-carrying capabilities under a variety of damage scenarios. In addition to improved structural performance, an important facet of this unique arrangement of stitched carbon fibers is its innovative manufacturing method that has the potential to lower fabrication costs by eliminating fasteners and autoclave cures. The rationale and development status for this new approach forms the basis of the work described in this paper. The test specimens described herein were fabricated, or are currently being fabricated, by The Boeing Company, while the structural analyses and testing tasks are being performed by NASA and Boeing personnel.

  8. The Concept of

    Directory of Open Access Journals (Sweden)

    ANCA VELICU

    2010-01-01

    Full Text Available The active publics issue and the question of the construction of publics are relatively recent in communication studies. After an initial period, when mass communication was seen as aiming at a holistic public, massified and passive and, thus, supposedly influenced via "targeted" messages, now the views on what "publics" mean is becoming diversified and nuanced under the influence of literary theories, cultural studies and what was later called "reception studies". Thus, from the "mass public" we got to the concept of "publics". However, in some recent studies, the mere existence of these publics is being questioned.In this paper, we detail the history of theories on the "public" - from the perspective of the public-as-spectator which later became public-as-audience and public-as-actor - and we set ourselves to show how, from theories on the re-active publics, we arrived, through the transformation of television and the emergence of the new IT&C, to the concept of publics as pro-active as a result of media efforts to build this activism.

  9. Concept of 'bad death'

    Directory of Open Access Journals (Sweden)

    Marija Vučković

    2016-02-01

    Full Text Available Following previous research on the linguistic concept of а 'bad death' which lexical expression is the word family of the verb ginuti, I focus my attention in this paper on the relationship between language conceptualization of а 'bad death' and the representation of а 'bad death' in traditional and contemporary culture. Diachronically based language corpus makes possible to trace the changes of referential frame and use of verb ginuti and its derivatives. In the traditional culture а 'bad death' is marked in action code by irregular way of burial and beliefs in demons stemming from the 'impure dead'. In the paper I explore the degree of synonymy of the symbols of all three codes: verbal code, action code and code of beliefs. In the contemporary culture the lack of individual control and choice is considered to be the key element of the concept of a 'bad death'. This change of conceptual content manifests itself in the use of its lexical expressions.

  10. Sellafield repository design concept

    International Nuclear Information System (INIS)

    1998-01-01

    Between 1989 and 1997, UK Nirex Ltd carried out a programme of investigations to evaluate the potential of a site adjacent to the BNFL Sellafield works to host a deep repository for the United Kingdom's intermediate-level and certain low-level radioactive waste. The programme of investigations was wound down following the decision in March 1997 to uphold the rejection of the Company's planning application for the Rock Characterisation Facility (RCF), an underground laboratory which would have allowed further investigations to confirm whether or not the site would be suitable. Since that time, the Company's efforts in relation to the Sellafield site have been directed towards documenting and publishing the work carried out. The design concept for a repository at Sellafield was developed in parallel with the site investigations through an iterative process as knowledge of the site and understanding of the repository system performance increased. This report documents the Sellafield repository design concept as it had been developed, from initial design considerations in 1991 up to the point when the RCF planning application was rejected. It shows, from the context of a project at that particular site, how much information and experience has been gained that will be applicable to the development of a deep waste repository at other potential sites

  11. The EXTRAP concept

    International Nuclear Information System (INIS)

    Lehnert, D.

    1976-11-01

    A review is given of a recently suggested axially symmetric, quasi-steady, closed, high-beta confinement system. A toroidal pinch of non-circular cross section is supposed to be immersed in the strong, inhomogenous poloidal vacuum field from a set of ring-shaped conductors, all carrying currents in the opposite direction of the plasma current. Preliminary experiments are reported. This 'EXTRAP' concept is expected to have some important advantages, as compared to magnetic bottles based on a main toroidal field component. Concerning plasma equilibrium, there are closed local and average guiding center orbits, beta values of order unity should become available, there is no magnetic surface splitting limit, cyclotron radiation should be kept at an acceptably low level, and bootstrap operation may become possible. Concerning plasma stability, the system should not become sensitive to magnetic island formation and asymmetries, and the short magnetic connection lengths as well as the strong vacuum field gradients should favour stabilization of flute-type, kink, and other magnetohydrodynamic modes. Concerning reactor technology, high power densities are expected to be reached, superconducting coils should not become necessary, the coil stresses are moderate, and repair and replacement are facilitated by the coil geometry. Before a final judgement can be made on this concept, however, extensive experiments and further theoretical analysis are ndeeded. (Auth.)

  12. Copies, Concepts and Time

    Directory of Open Access Journals (Sweden)

    Anne Eriksen

    2017-09-01

    Full Text Available Copies are defined by their relation to an original. The understanding and evaluation of this relationship has been changing over time. A main argument of this article is that originals and copies are phenomena with no "natural" or essential meaning outside of their specific historical settings. The idea to be explored is how changing historicity regimes have transformed notions of originals and copies over time and how these differences also are reflected in the intrinsically temporal relation between the two concepts. The discussion will be framed by two theory sets. The first is Alexander Nagel and Christopher Woods investigation of two kinds of temporality that vied for dominance in works of art in the late Middle Ages and the Renaissance. The second is Walter Benjamins discussion of artwork in the "age of mechanical reproduction", i.e. the twentieth century. The second half of the article seeks to add to the historical complexity described by both theory sets by introducing a concept of tradition and discussing the early modern ideals of exemplarity, emulation and copiousness.

  13. Concepts of magnetospheric convection

    International Nuclear Information System (INIS)

    Vasyliunas, V.M.

    1975-01-01

    Magnetospheric physics, which grew out of attempts to understand the space environment of the Earth, is becoming increasingly applicable to other systems in the Universe. Among the planets, in addition to the Earth, Jupiter, Mercury, Mars and (in a somewhat different way) Venus are now known to have magnetospheres. The magnetospheres of pulsars have been regarded as an essential part of the pulsar phenomenon. Other astrophysical systems, such as supernova remnant shells or magnetic stars and binary star systems, may be describable as magnetospheres. The major concepts of magnetospheric physics thus need to be formulated in a general way not restricted to the geophysical context in which they may have originated. Magnetospheric convection has been one of the most important and fruitful concepts in the study of the Earth's magnetosphere. This paper describes the basic theoretical notions of convection in a manner applicable to magnetospheres generally and discusses the relative importance of convective corotational motions, with particular reference to the comparison of the Earth and Jupiter. (Auth.)

  14. Separations innovative concepts: Project summary

    Energy Technology Data Exchange (ETDEWEB)

    Lee, V.E. (ed.)

    1988-05-01

    This project summary includes the results of 10 innovations that were funded under the US Department's Innovative Concept Programs. The concepts address innovations that can substantially reduce the energy used in industrial separations. Each paper describes the proposed concept, and discusses the concept's potential energy savings, market applications, technical feasibility, prior work and state of the art, and future development needs.

  15. Online Exhibits & Concept Maps

    Science.gov (United States)

    Douma, M.

    2009-12-01

    Presenting the complexity of geosciences to the public via the Internet poses a number of challenges. For example, utilizing various - and sometimes redundant - Web 2.0 tools can quickly devour limited time. Do you tweet? Do you write press releases? Do you create an exhibit or concept map? The presentation will provide participants with a context for utilizing Web 2.0 tools by briefly highlighting methods of online scientific communication across several dimensions. It will address issues of: * breadth and depth (e.g. from narrow topics to well-rounded views), * presentation methods (e.g. from text to multimedia, from momentary to enduring), * sources and audiences (e.g. for experts or for the public, content developed by producers to that developed by users), * content display (e.g. from linear to non-linear, from instructive to entertaining), * barriers to entry (e.g. from an incumbent advantage to neophyte accessible, from amateur to professional), * cost and reach (e.g. from cheap to expensive), and * impact (e.g. the amount learned, from anonymity to brand awareness). Against this backdrop, the presentation will provide an overview of two methods of online information dissemination, exhibits and concept maps, using the WebExhibits online museum (www.webexhibits.org) and SpicyNodes information visualization tool (www.spicynodes.org) as examples, with tips on how geoscientists can use either to communicate their science. Richly interactive online exhibits can serve to engage a large audience, appeal to visitors with multiple learning styles, prompt exploration and discovery, and present a topic’s breadth and depth. WebExhibits, which was among the first online museums, delivers interactive information, virtual experiments, and hands-on activities to the public. While large, multidisciplinary exhibits on topics like “Color Vision and Art” or “Calendars Through the Ages” require teams of scholars, user interface experts, professional writers and editors

  16. Can We Feel Physics Concepts?

    Science.gov (United States)

    Su, Yucheng

    2010-01-01

    There are many ways to improve students' understanding of physics concepts. This article focused on drawing students' attention with picture-embedded questions. Pictures give students a direct impression or feeling about the corresponding concepts, which really makes a difference. However, the effects are limited. Some physics concepts are…

  17. The Concept of Philosophical Education

    Science.gov (United States)

    Boyum, Steinar

    2010-01-01

    Strangely, the concept of philosophical education is not much in use, at least not as a "philosophical" concept. In this essay, Steinar Boyum attempts to outline such a philosophical concept of philosophical education. Boyum uses Plato's Allegory of the Cave, Rene Descartes's life of doubt, and Immanuel Kant's criticism of metaphysics as paradigms…

  18. Disentangling The Thick Concept Argument

    DEFF Research Database (Denmark)

    Blomberg, Olle

    2007-01-01

    Critics argue that non-cognitivism cannot adequately account for the existence and nature of some thick moral concepts. They use the existence of thick concepts as a lever in an argument against non-cognitivism, here called the Thick Concept Argument (TCA). While TCA is frequently invoked...

  19. Concepts of Chinese Folk Happiness

    Science.gov (United States)

    Ip, Po Keung

    2011-01-01

    Discourses on Chinese folk happiness are often based on anecdotal narratives or qualitative analysis. Two traditional concepts of happiness popular in Chinese culture are introduced. The paper constructs a concept of Chinese folk happiness on basis of the findings of a scientific survey on the Taiwanese people regarding their concepts of…

  20. COMPETING CONCEPTIONS OF GLOBALIZATION

    Directory of Open Access Journals (Sweden)

    Leslie Sklair

    2015-08-01

    Full Text Available Globalization is a relatively new idea in the social sciences, although people who work in and write about the mass media, transnational corporations and international business have been using it for some time. The purpose of this paper is to critically review the ways in which sociologists and other social scientists use ideas of globalization and to evaluate the fruitfulness of these competing conceptions. The central feature of the idea of globalization is that many contemporary problems cannot be adequately studied at the level of nation-states, that is, in terms of each country and its inter-national relations. Instead, they need to be conceptualized in terms of global processes. Some have even gone so far as to predict that global forces, by which they usually mean transnational corporations and other global economic institutions, global culture or globalizing belief systems/ideologies of various types, or a combination of all of these, are becoming so powerful that the continuing existence of the nation-state is in serious doubt. This is not a necessary consequence of most theories of globalization. The argument of this paper is that much of the globalization literature is confused because not all those who use the term distinguish it clearly enough from internation-alization, and some writers appear to use the two terms interchangeably. I argue that a clear distinction must be drawn between the inter-national and the global. The hyphen in inter-national is to distinguish (inadequate conceptions of the global' founded on the existing even if changing system of nation-states, from (genuine conceptions of the global based on the emergence of global processes and a global system of social relations not founded on national characteristics or nation-states. This global system theory is the framework for my own research. Globalization studies can be categorized on the basis of four research clusters:1. The world-systems approach; 2. The global