WorldWideScience

Sample records for unit blade section

  1. New airfoil sections for straight bladed turbine

    Science.gov (United States)

    Boumaza, B.

    1987-07-01

    A theoretical investigation of aerodynamic performance for vertical axis Darrieus wind turbine with new airfoils sections is carried out. The blade section aerodynamics characteristics are determined from turbomachines cascade model. The model is also adapted to the vertical Darrieus turbine for the performance prediction of the machine. In order to choose appropriate value of zero-lift-drag coefficient in calculation, an analytical expression is introduced as function of chord-radius ratio and Reynolds numbers. New airfoils sections are proposed and analyzed for straight-bladed turbine.

  2. New airfoil sections for straight bladed turbine

    International Nuclear Information System (INIS)

    Boumaza, B.

    1987-07-01

    A theoretical investigation of aerodynamic performance for vertical axis Darrieus wind turbine with new airfoils sections is carried out. The blade section aerodynamics characteristics are determined from turbomachines cascade model. The model is also adapted to the vertical Darrieus turbine for the performance prediction of the machine. In order to choose appropriate value of zero-lift-drag coefficient in calculation, an analytical expression is introduced as function of chord-radius ratio and Reynolds numbers. New airfoils sections are proposed and analyzed for straight-bladed turbine

  3. Noise from Propellers with Symmetrical Sections at Zero Blade Angle

    Science.gov (United States)

    Deming, A F

    1937-01-01

    A theory has been deduced for the "rotation noise" from a propeller with blades of symmetrical section about the chord line and set at zero blade angle. Owing to the limitation of the theory, the equations give without appreciable error only the sound pressure for cases where the wave lengths are large compared with the blade lengths. With the aid of experimental data obtained from a two-blade arrangement, an empirical relation was introduced that permitted calculation of higher harmonics. The generality of the final relation given is indicated by the fundamental and second harmonic of a four-blade arrangement.

  4. Unsteady potential flow past a propeller blade section

    Science.gov (United States)

    Takallu, M. A.

    1990-01-01

    An analytical study was conducted to predict the effect of an oscillating stream on the time dependent sectional pressure and lift coefficients of a model propeller blade. The assumption is that as the blade sections encounter a wake, the actual angles of attack vary in a sinusoidal manner through the wake, thus each blade is exposed to an unsteady stream oscillating about a mean value at a certain reduced frequency. On the other hand, an isolated propeller at some angle of attack can experience periodic changes in the value of the flow angle causing unsteady loads on the blades. Such a flow condition requires the inclusion of new expressions in the formulation of the unsteady potential flow around the blade sections. These expressions account for time variation of angle of attack and total shed vortices in the wake of each airfoil section. It was found that the final expressions for the unsteady pressure distribution on each blade section are periodic and that the unsteady circulation and lift coefficients exhibit a hysteresis loop.

  5. blades

    Directory of Open Access Journals (Sweden)

    Shashishekara S. Talya

    1999-01-01

    Full Text Available Design optimization of a gas turbine blade geometry for effective film cooling toreduce the blade temperature has been done using a multiobjective optimization formulation. Three optimization formulations have been used. In the first, the average blade temperature is chosen as the objective function to be minimized. An upper bound constraint has been imposed on the maximum blade temperature. In the second, the maximum blade temperature is chosen as the objective function to be minimized with an upper bound constraint on the average blade temperature. In the third formulation, the blade average and maximum temperatures are chosen as objective functions. Shape optimization is performed using geometric parameters associated with film cooling and blade external shape. A quasi-three-dimensional Navier–Stokes solver for turbomachinery flows is used to solve for the flow field external to the blade with appropriate modifications to incorporate the effect of film cooling. The heat transfer analysis for temperature distribution within the blade is performed by solving the heat diffusion equation using the finite element method. The multiobjective Kreisselmeier–Steinhauser function approach has been used in conjunction with an approximate analysis technique for optimization. The results obtained using both formulations are compared with reference geometry. All three formulations yield significant reductions in blade temperature with the multiobjective formulation yielding largest reduction in blade temperature.

  6. Structural fatigue test results for large wind turbine blade sections

    Science.gov (United States)

    Faddoul, J. R.; Sullivan, T. L.

    1982-01-01

    In order to provide quantitative information on the operating life capabilities of wind turbine rotor blade concepts for root-end load transfer, a series of cantilever beam fatigue tests was conducted. Fatigue tests were conducted on a laminated wood blade with bonded steel studs, a low cost steel spar (utility pole) with a welded flange, a utility pole with additional root-end thickness provided by a swaged collar, fiberglass spars with both bonded and nonbonded fittings, and, finally, an aluminum blade with a bolted steel fitting (Lockheed Mod-0 blade). Photographs, data, and conclusions for each of these tests are presented. In addition, the aluminum blade test results are compared to field failure information; these results provide evidence that the cantilever beam type of fatigue test is a satisfactory method for obtaining qualitative data on blade life expectancy and for identifying structurally underdesigned areas (hot spots).

  7. New morphing blade section designs and structural solutions for smart blades

    DEFF Research Database (Denmark)

    Karakalas, Anargyros A.; Machairas, Theodore; Solomou, Alexandros

    2015-01-01

    Within INNWIND.EU new concepts are investigated having the ultimate goal to reduce the cost per kilowatt-hour of the produced energy. With increasing size of wind turbines, new approaches to load control are required to reduce the stresses in blades. Experimental and numerical studies in the fields...... of helicopter and wind turbine blade research have shown the potential of shape morphing in reducing blade loads. Morphing technologies, along with other control concepts, are investigated under Task 2.3 of WP “Lightweight Rotor”, against aerodynamic compliance and requirements of the complete wind turbine...... the efforts performed within Task 2.2 “Lightweight structural design” of INNWIND.Eu work-package WP2 “Lightweight Rotor” regarding the structural solutions necessary to accommodate the requirements of smart blades developed within work-package WP2 Task 2.3 “Active and passive loads control and alleviation...

  8. Numerical study of Wavy Blade Section for Wind Turbines

    DEFF Research Database (Denmark)

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

    2016-01-01

    than a flipper having a smooth trailing edge and thus could be potentially beneficial when catching food. A thorough literature study of the Wavy Blade concept is made and followed by CFD computations of two wavy blade geometries and a comparison with their baseline S809 airfoil at conditions more...

  9. Effect of the flow characteristics and inter blade channel shape on the losses in peripheral sections of gas turbine blades

    International Nuclear Information System (INIS)

    Granovskij, A.V.; Kostezh, M.K.

    1999-01-01

    The results of calculational study , based on the solution of the Navier-Stokes equations, on the floe structure and the level of profile losses in the peripheral cross sections of turbine blades by the Re = 2.0 x 10 5 - 1.2 x 10 6 numbers and the turbulence inlet intensity 0.02 - 0.12 are presented

  10. New Design of Blade Untwisting Device of Cyclone Unit

    Directory of Open Access Journals (Sweden)

    D. I. Misiulia

    2010-01-01

    Full Text Available The paper presents a new design of a blade untwisting device where blades are considered as a main element of the device. A profile of the blades corresponds to a circular arch. An inlet angle of  the blades is determined by stream aerodynamics in an exhaust pipe, and an exit angle is determined by rectilinear gas motion. Optimum geometrical parameters of the untwisting device have been determined and its application allows to reduce a pressure drop in the ЦН-15 cyclones by 28–30 % while screw-blade untwisting device recovers only 19–20 % of energy.

  11. Blade Section Lift Coefficients for Propellers at Extreme Off-Design Conditions

    National Research Council Canada - National Science Library

    Shen, Young

    1997-01-01

    The Propeller Force Module (PFM) code developed by Analytical Methods Inc. (AMI) for calculating propeller side forces during maneuvering simulation studies requires inputs of propeller blade sectional lift, drag, and moment data...

  12. 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.

  13. Section curve reconstruction and mean-camber curve extraction of a point-sampled blade surface.

    Directory of Open Access Journals (Sweden)

    Wen-long Li

    Full Text Available The blade is one of the most critical parts of an aviation engine, and a small change in the blade geometry may significantly affect the dynamics performance of the aviation engine. Rapid advancements in 3D scanning techniques have enabled the inspection of the blade shape using a dense and accurate point cloud. This paper proposes a new method to achieving two common tasks in blade inspection: section curve reconstruction and mean-camber curve extraction with the representation of a point cloud. The mathematical morphology is expanded and applied to restrain the effect of the measuring defects and generate an ordered sequence of 2D measured points in the section plane. Then, the energy and distance are minimized to iteratively smoothen the measured points, approximate the section curve and extract the mean-camber curve. In addition, a turbine blade is machined and scanned to observe the curvature variation, energy variation and approximation error, which demonstrates the availability of the proposed method. The proposed method is simple to implement and can be applied in aviation casting-blade finish inspection, large forging-blade allowance inspection and visual-guided robot grinding localization.

  14. Cooling of Gas Turbines. 6; Computed Temperature Distribution Through Cross Section of Water-Cooled Turbine Blade

    Science.gov (United States)

    Livingood, John N. B.; Sams, Eldon W.

    1947-01-01

    A theoretical analysis of the cross-sectional temperature distribution of a water-cooled turbine blade was made using the relaxation method to solve the differential equation derived from the analysis. The analysis was applied to specific turbine blade and the studies icluded investigations of the accuracy of simple methods to determine the temperature distribution along the mean line of the rear part of the blade, of the possible effect of varying the perimetric distribution of the hot gas-to -metal heat transfer coefficient, and of the effect of changing the thermal conductivity of the blade metal for a constant cross sectional area blade with two quarter inch diameter coolant passages.

  15. Roughness Sensitivity Comparisons of Wind Turbine Blade Sections

    Energy Technology Data Exchange (ETDEWEB)

    Wilcox, Benjamin J. [Texas A & M Univ., College Station, TX (United States). Dept. of Aerospace Engineering; White, Edward B. [Texas A & M Univ., College Station, TX (United States). Dept. of Aerospace Engineering; Maniaci, David Charles [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Wind Energy Technologies Dept.

    2017-10-01

    One explanation for wind turbine power degradation is insect roughness. Historical studies on insect-induced power degradation have used simulation methods which are either un- representative of actual insect roughness or too costly or time-consuming to be applied to wide-scale testing. Furthermore, the role of airfoil geometry in determining the relations between insect impingement locations and roughness sensitivity has not been studied. To link the effects of airfoil geometry, insect impingement locations, and roughness sensitivity, a simulation code was written to determine representative insect collection patterns for different airfoil shapes. Insect collection pattern data was then used to simulate roughness on an NREL S814 airfoil that was tested in a wind tunnel at Reynolds numbers between 1.6 x 106 and 4.0 x 106. Results are compared to previous tests of a NACA 633 -418 airfoil. Increasing roughness height and density results in decreased maximum lift, lift curve slope, and lift-to-drag ratio. Increasing roughness height, density, or Reynolds number results in earlier bypass transition, with critical roughness Reynolds numbers lying within the historical range. Increased roughness sensitivity on the 25% thick NREL S814 is observed compared to the 18% thick NACA 63 3 -418. Blade-element-momentum analysis was used to calculate annual energy production losses of 4.9% and 6.8% for a NACA 633 -418 turbine and an NREL S814 turbine, respectively, operating with 200 μm roughness. These compare well to historical field measurements.

  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. 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

  18. Four-Point Bending Strength Testing of Pultruded Fiberglass Composite Wind Turbine Blade Sections

    International Nuclear Information System (INIS)

    Musial, W.; Bourne, B; Hughes, S; Zuteck, M. D.

    2001-01-01

    The ultimate strength of the PS Enterprises pultruded blade section was experimentally determined under four-point bending at the National Renewable Energy Laboratory. Thirteen 8-foot long full-scale blade segments were individually tested to determine their maximum moment carrying capability. Three airfoil-bending configurations were tested: high- and low-pressure skin buckling, and low pressure skin buckling with foam interior reinforcement. Maximum strain was recorded for each sample on the compressive and tensile surfaces of each test blade. Test data are compared to the results of three analytical buckling prediction methods. Based on deviations from the linear strain versus load curve, data indicate a post-buckling region. High-pressure side buckling occurred sooner than low-pressure side buckling. The buckling analyses were conservative for both configurations, but high-pressure side buckling in particular was substantially under-predicted. Both high- and low-pressure buckling configurations had very similar failure loads. These results suggests that a redundant load path may be providing strength to the section in the post-buckling region, making the onset of panel buckling a poor predictor of ultimate strength for the PS Enterprises pultrusion

  19. Complementary Aerodynamic Performance Datasets for Variable Speed Power Turbine Blade Section from Two Independent Transonic Turbine Cascades

    Science.gov (United States)

    Flegel, Ashlie B.; Welch, Gerard E.; Giel, Paul W.; Ames, Forrest E.; Long, Jonathon A.

    2015-01-01

    Two independent experimental studies were conducted in linear cascades on a scaled, two-dimensional mid-span section of a representative Variable Speed Power Turbine (VSPT) blade. The purpose of these studies was to assess the aerodynamic performance of the VSPT blade over large Reynolds number and incidence angle ranges. The influence of inlet turbulence intensity was also investigated. The tests were carried out in the NASA Glenn Research Center Transonic Turbine Blade Cascade Facility and at the University of North Dakota (UND) High Speed Compressible Flow Wind Tunnel Facility. A large database was developed by acquiring total pressure and exit angle surveys and blade loading data for ten incidence angles ranging from +15.8deg to -51.0deg. Data were acquired over six flow conditions with exit isentropic Reynolds number ranging from 0.05×106 to 2.12×106 and at exit Mach numbers of 0.72 (design) and 0.35. Flow conditions were examined within the respective facility constraints. The survey data were integrated to determine average exit total-pressure and flow angle. UND also acquired blade surface heat transfer data at two flow conditions across the entire incidence angle range aimed at quantifying transitional flow behavior on the blade. Comparisons of the aerodynamic datasets were made for three "match point" conditions. The blade loading data at the match point conditions show good agreement between the facilities. This report shows comparisons of other data and highlights the unique contributions of the two facilities. The datasets are being used to advance understanding of the aerodynamic challenges associated with maintaining efficient power turbine operation over a wide shaft-speed range.

  20. Noise from propellers with symmetrical sections at zero blade angle, II

    Science.gov (United States)

    Deming, A F

    1938-01-01

    In a previous paper (Technical Note No. 605), a theory was developed that required an empirical relation to calculate sound pressures for the higher harmonics. Further investigation indicated that the modified theory agrees with experiment and that the empirical relation was due to an interference phenomenon peculiar to the test arrangement used. Comparison is made between the test results for a two-blade arrangement and the theory. The comparison is made for sound pressures in the plane of the revolving blades for varying values of tip velocity. Comparison is also made at constant tip velocity for all values of azimuth angle B. A further check is made between the theory and the experimental results for the fundamental of a four-blade arrangement with blades of the same dimensions as those used in the two-blade arrangement.

  1. Assessment of the performance of various airfoil sections on power generation from a wind turbine using the blade element momentum theory

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xiaomin; Agarwal, Ramesh [Department of Mechanical Engineering and Materials Science, Washington University in St. Louis, Jolley Hall, Campus Box 1185, One Brookings Drive, St. Louis, Missouri, 63130 (United States)

    2013-07-01

    It is well established that the power generated by a Horizontal-Axis Wind Turbine (HAWT) is a function of the number of blades, the tip speed ratio (blade tip speed/wind free stream velocity) and the lift to drag ratio (CL /CD) of the airfoil sections of the blade. The airfoil sections used in HAWT are generally thick airfoils such as the S, DU, FX, Flat-back and NACA 6-series of airfoils. These airfoils vary in (CL /CD) for a given blade and ratio and therefore the power generated by HAWT for different blade airfoil sections will vary. The goal of this paper is to evaluate the effect of different airfoil sections on HAWT performance using the Blade Element Momentum (BEM) theory. In this study, we employ DU 91-W2-250, FX 66-S196-V1, NACA 64421, and Flat-back series of airfoils (FB-3500-0050, FB-3500-0875, and FB-3500-1750) and compare their performance with S809 airfoil used in NREL Phase II and III wind turbines; the lift and drag coefficient data for these airfoils sections are available. The output power of the turbine is calculated using these airfoil section blades for a given blade and ratio and is compared with the original NREL Phase II and Phase III turbines using S809 airfoil section. It is shown that by a suitable choice of airfoil section of HAWT blade, the power generated by the turbine can be significantly increased. Parametric studies are also conducted by varying the turbine diameter.

  2. Spatial reliability analysis of a wind turbine blade cross section subjected to multi-axial extreme loading

    DEFF Research Database (Denmark)

    Dimitrov, Nikolay Krasimirov; Bitsche, Robert; Blasques, José Pedro Albergaria Amaral

    2017-01-01

    This paper presents a methodology for structural reliability analysis of wind turbine blades. The study introduces several novel elements by taking into account loading direction using a multiaxial probabilistic load model, considering random material strength, spatial correlation between material...... properties, progressive material failure, and system reliability effects. An example analysis of reliability against material failure is demonstrated for a blade cross section. Based on the study we discuss the implications of using a system reliability approach, the effect of spatial correlation length......, type of material degradation algorithm, and reliability methods on the system failure probability, as well as the main factors that have an influence on the reliability. (C) 2017 Elsevier Ltd. All rights reserved....

  3. 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...

  4. 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...

  5. 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

  6. 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.

  7. 24 CFR 882.123 - Conversion of Section 23 Units to Section 8 and Section 23 monitoring.

    Science.gov (United States)

    2010-04-01

    ... 24 Housing and Urban Development 4 2010-04-01 2010-04-01 false Conversion of Section 23 Units to... Applicability, Scope and Basic Policies § 882.123 Conversion of Section 23 Units to Section 8 and Section 23 monitoring. (a)-(d) [Reserved] (e) Section 23 policies for units planned for conversion on or before...

  8. Advanced LP turbine blade design

    International Nuclear Information System (INIS)

    Jansen, M.; Pfeiffer, R.; Termuehlen, H.

    1990-01-01

    In the 1960's and early 1970's, the development of steam turbines for the utility industry was mainly influenced by the demand for increasing unit sizes. Nuclear plants in particular, required the design of LP turbines with large annulus areas for substantial mass and volumetric steam flows. Since then the development of more efficient LP turbines became an ongoing challenge. Extensive R and D work was performed in order to build efficient and reliable LP turbines often exposed to severe corrosion, erosion and dynamic excitation conditions. This task led to the introduction of an advanced disk-type rotor design for 1800 rpm LP turbines and the application of a more efficient, reaction-type blading for all steam turbine sections including the first stages of LP turbines. The most recent developments have resulted in an advanced design of large LP turbine blading, typically used in the last three stages of each LP turbine flow section. Development of such blading required detailed knowledge of the three dimensional, largely transonic, flow conditions of saturated steam. Also the precise assessment of blade stressing from dynamic conditions, such as speed and torsional resonance, as well as stochastic and aerodynamic excitation is of extreme importance

  9. 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.

  10. Effects of geometric non-linearity on energy release rates in a realistic wind turbine blade cross section

    DEFF Research Database (Denmark)

    Eder, Martin Alexander; Bitsche, Robert; Belloni, Federico

    2015-01-01

    Most wind turbine rotor blades comprise several adhesively connected sub-components typically made from glass fibre reinforced polymer composite materials. It is a well-known fact that wind turbine blades are prone to fail in their adhesive joints. However, owing to the complexity...... of their structural behaviour, little is known about the root causes of adhesive joint failure. This paper investigates the effects of geometrical non-linearity on energy release rates (ERRs) of transversely oriented cracks present in the adhesive joints of a wind turbine rotor blade. Utilising a computationally...

  11. Blade dynamic stress analysis of rotating bladed disks

    Directory of Open Access Journals (Sweden)

    Kellner J.

    2007-10-01

    Full Text Available The paper deals with mathematical modelling of steady forced bladed disk vibrations and with dynamic stress calculation of the blades. The blades are considered as 1D kontinuum elastic coupled with three-dimensional elastic disk centrally clamped into rotor rotating with constant angular speed. The steady forced vibrations are generated by the aerodynamic forces acting along the blade length. By using modal synthesis method the mathematical model of the rotating bladed disk is condensed to calculate steady vibrations. Dynamic stress analysis of the blades is based on calculation of the time dependent reduced stress in blade cross-sections by using Hubert-Misses-Hencky stress hypothesis. The presented method is applied to real turbomachinery rotor with blades connected on the top with shroud.

  12. Investigation of Dynamic Aerodynamics and Control of Wind Turbine Sections Under Relevant Inflow/Blade Attitude Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Naughton, Jonathan W. [University of Wyoming

    2014-08-05

    The growth of wind turbines has led to highly variable loading on the blades. Coupled with the relative reduced stiffness of longer blades, the need to control loading on the blades has become important. One method of controlling loads and maximizing energy extraction is local control of the flow on the wind turbine blades. The goal of the present work was to better understand the sources of the unsteady loading and then to control them. This is accomplished through an experimental effort to characterize the unsteadiness and the effect of a Gurney flap on the flow, as well as an analytical effort to develop control approaches. It was planned to combine these two efforts to demonstrate control of a wind tunnel test model, but that final piece still remains to be accomplished.

  13. Super titanium blades for advanced steam turbines

    International Nuclear Information System (INIS)

    Coulon, P.A.

    1990-01-01

    In 1986, the Alsthom Steam Turbines Department launched the manufacture of large titanium alloy blades: airfoil length of 1360 mm and overall length of 1520 mm. These blades are designed for the last-stage low pressure blading of advanced steam turbines operating at full speed (3000 rpm) and rating between 300 and 800 MW. Using titanium alloys for steam turbine exhaust stages as substitutes for chrome steels, due to their high strength/density ratio and their almost complete resistance to corrosion, makes it possible to increase the length of blades significantly and correspondingly that steam passage section (by up to 50%) with a still conservative stresses level in the rotor. Alsthom relies on 8 years of experience in the field of titanium, since as early as 1979 large titanium blades (airfoil length of 1240 mm, overall length of 1430 mm) were erected for experimental purposes on the last stage of a 900 MW unit of the Dampierre-sur-Loire power plant and now totals 45,000 operating hours without problems. The paper summarizes the main properties (chemical, mechanical and structural) recorded on very large blades and is based in particular on numerous fatigue corrosion test results to justify the use of the Ti 6 Al 4 V alloy in a specific context of micrographic structure

  14. Numerical investigation on aerodynamic performance of a novel vertical axis wind turbine with adaptive blades

    International Nuclear Information System (INIS)

    Wang, Ying; Sun, Xiaojing; Dong, Xiaohua; Zhu, Bing; Huang, Diangui; Zheng, Zhongquan

    2016-01-01

    Highlights: • A novel vertical axis wind turbine with deformed blades is designed. • The universal tendency of power characteristics for simulated turbine is found. • The whole flow field of different turbines from the aspect of vortex is analyzed. • The tracking analysis of vortex at different positions for a blade is conducted. • The aerodynamic performance of turbine with three deformed blades is analyzed. - Abstract: In this paper, a novel Darrieus vertical axis wind turbine was designed whose blade can be deformed automatically into a desired geometry and thus achieve a better aerodynamic performance. A series of numerical simulations were conducted by utilizing the United Computational Fluid Dynamics code. Firstly, analysis and comparison of the performance of undeformed and deformed blades for the rotors having different blades were conducted. Then, the power characteristics of each simulated turbine were summarized and a universal tendency was found. Secondly, investigation on the effect of blade number and solidity on the power performance of Darrieus vertical axis wind turbine with deformable and undeformable blades was carried out. The results indicated that compared to conventional turbines with same solidity, the maximum percentage increase in power coefficient that the low solidity turbine with three deformable blades can achieve is about 14.56%. When solidity is high and also turbine operates at low tip speed ratio of less than the optimum value, the maximum power coefficient increase for the turbines with two and four deformable blades are 7.51% and 8.07%, respectively. However, beyond the optimal tip speed ratio, the power improvement of the turbine using the deformable blades seems not significant and even slightly worse than the conventional turbines. The last section studied the transient behavior of vortex and turbulent flow structures around the deformable rotor blade to explore the physical mechanism of improving aerodynamic

  15. Production of short straight sections hits 100 units

    CERN Multimedia

    2005-01-01

    The 100th short straight section for the Large Hadron Collider was assembled at CERN at the beginning of April. These units combine superconducting quadrupoles and other multipole corrector magnets, housed in their cryostats, which are used to guide, focus and fine-tune the beam in the LHC. Building 904, where the 474 short straight sections are being assembled, is often called "Lego Land" by the workers, with a touch of humor and pride because of the wide variety of these sets of magnets and cryostats .

  16. Korean experience with steam turbine blade inspection

    International Nuclear Information System (INIS)

    Jung, Hyun Kyu; Park, D.Y.; Park, Hyung Jin; Chung, Min Hwa

    1990-01-01

    Several turbine blade accidents in Korea have emphasized the importance of their adequate periodic inspection. As a typical example, a broken blade was found in the Low Pressure (LP) turbine at the 950 MWe KORI unit 3 during the 1986 overhaul after one year commercial operation. Since then the Manufacturer and the Utility company (KEPCO) have been concerned about the need of blade root inspection. The ultrasonic testing was applied to detect cracks in the blade roots without removing the blades from rotor. Due to the complex geometry of the roots, the test results could not be evaluated easily. We feel that the currently applied UT technique seems to be less reliable and more effective method of inspection must be developed in the near future. This paper describes the following items: The causes and analysis of blade damage The inspection techniques and results The remedial action to be taken (Repair and Replacement) The future plan

  17. 49 CFR 236.707 - Blade, semaphore.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Blade, semaphore. 236.707 Section 236.707 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Blade, semaphore. The extended part of a semaphore arm which shows the position of the arm. ...

  18. 3 CFR - Designation of Officers of the United States Section, International Boundary and Water Commission...

    Science.gov (United States)

    2010-01-01

    ... 3 The President 1 2010-01-01 2010-01-01 false Designation of Officers of the United States Section, International Boundary and Water Commission, United States and Mexico To Act as the Commissioner of the United... States and Mexico To Act as the Commissioner of the United States Section Memorandum for the Commissioner...

  19. Design of Wind Turbine Blades

    DEFF Research Database (Denmark)

    McGugan, Malcolm

    2016-01-01

    In this section the research program framework for European PhD network MARE-WINT is presented, particularly the technology development work focussing on reliability/maintenance and the models describing multi-body fluid structure interaction for the Rotor Blade structure. In order to give...

  20. Turbomachine blade reinforcement

    Science.gov (United States)

    Garcia Crespo, Andres Jose

    2016-09-06

    Embodiments of the present disclosure include a system having a turbomachine blade segment including a blade and a mounting segment coupled to the blade, wherein the mounting segment has a plurality of reinforcement pins laterally extending at least partially through a neck of the mounting segment.

  1. Turbomachine blade assembly

    Science.gov (United States)

    Garcia Crespo, Andres Jose

    2016-11-01

    Embodiments of the present disclosure include a system comprising a turbomachine blade assembly having a blade portion, a shank portion, and a mounting portion, wherein the blade portion, the shank portion, and the mounting portion comprise a first plurality of plies extending from a tip of the airfoil to a base of the dovetail.

  2. Wind Turbine Blade

    DEFF Research Database (Denmark)

    2010-01-01

    The invention relates to a blade for a wind turbine, particularly to a blade that may be produced by an advanced manufacturing process for producing a blade with high quality structural components. Particularly, the structural components, which are preferably manufactured from fibre reinforced...

  3. Measurements of blade aerodynamics on a rotor in the field

    Energy Technology Data Exchange (ETDEWEB)

    Graham, J.M.R. [Imperical College, Dept. of Aeronautics, London (United Kingdom)

    1997-12-31

    This contribution describes the field test measurements undertaken on an instrumented rotor at the Rutherford Appleton Laboratory, Oxfordshire, UK, during the period 1994 - 97. The programme was directed at improving the prediction of the steady and unsteady rotor blade loading, particularly the loads arising from the stalling of the blade. The measured data consisted of blade surface pressure distributions sampled at 50Hz at 6 sections along the span of one blade of the 17m diameter, 3 bladed, fixed pitch, upwind H.A.W.T., together with measurements of the incident velocity. (au)

  4. Vibration and flutter of mistuned bladed-disk assemblies

    Science.gov (United States)

    Kaza, K. R. V.; Kielb, R. E.

    1984-01-01

    An analytical model for investigating vibration and flutter of mistuned bladed disk assemblies is presented. This model accounts for elastic, inertial and aerodynamic coupling between bending and torsional motions of each individual blade, elastic and inertial couplings between the blades and the disk, and aerodynamic coupling among the blades. The disk was modeled as a circular plate with constant thickness and each blade was represented by a twisted, slender, straight, nonuniform, elastic beam with a symmetric cross section. The elastic axis, inertia axis, and the tension axis were taken to be noncoincident and the structural warping of the section was explicitly considered. The blade aerodynamic loading in the subsonic and supersonic flow regimes was obtained from two-dimensional unsteady, cascade theories. All the possible standing wave modes of the disk and traveling wave modes of the blades were included. The equations of motion were derived by using the energy method in conjunction with the assumed mode shapes for the disk and the blades. Continuities of displacement and slope at the blade-disk junction were maintained. The equations were solved to investigate the effects of blade-disk coupling and blade frequency mistuning on vibration and flutter. Results showed that the flexibility of practical disks such as those used for current generation turbofans did not have a significant influence on either the tuned or mistuned flutter characteristics. However, the disk flexibility may have a strong influence on some of the system frequencies and on forced response.

  5. Blade-element/momentum theory

    DEFF Research Database (Denmark)

    Sørensen, Jens Nørkær

    2016-01-01

    Although there exists a large variety of methods for predicting performance and loadings of wind turbines, the only approach used today by wind turbine manufacturers is based on the blade-element/momentum (BEM) theory by Glauert (Aerodynamic theory. Springer, Berlin, pp. 169-360, 1935). A basic...... assumption in the BEM theory is that the flow takes place in independent stream tubes and that the loading is determined from two-dimensional sectional airfoil characteristics....

  6. Development of 52 inches last stage blade for steam turbines

    International Nuclear Information System (INIS)

    Suzuki, Atsuhide; Hisa, Shoichi; Nagao, Shinichiro; Ogata, Hisao

    1986-01-01

    The last stage blades of steam turbines are the important component controlling the power output and performance of plants. In order to realize a unit of large capacity and high efficiency, the proper exhaust area and the last stage blades having good performance are indispensable. Toshiba Corp. has completed the development of the 52 inch last stage blades for 1500 and 1800 rpm steam turbines. The 52 inch last stage blades are the longest in the world, which have the annular exhaust area nearly 1.5 times as much as that of 41 inch blades used for 1100 MW, 1500 rpm turbines in nuclear power stations. By adopting these 52 inch blades, the large capacity nuclear power plants up to 1800 MW can be economically constructed, the rate of heat consumption of 1350 MW plants is improved by 3 ∼ 4 % as compared with 41 inch blades, and in the plants up to 1100 MW, LP turbines can be reduced from three sets to two. The features of 52 inch blades, the flow pattern and blade form design, the structural strength analysis and the erosion withstanding property, and the verification by the rotation test of the actual blades, the performance test using a test turbine, the vibration analysis of the actually loaded blades and the analysis of wet steam behavior are reported. (Kako, I.)

  7. Wind turbine blade waste in 2050.

    Science.gov (United States)

    Liu, Pu; Barlow, Claire Y

    2017-04-01

    Wind energy has developed rapidly over the last two decades to become one of the most promising and economically viable sources of renewable energy. Although wind energy is claimed to provide clean renewable energy without any emissions during operation, but it is only one side of the coin. The blades, one of the most important components in the wind turbines, made with composite, are currently regarded as unrecyclable. With the first wave of early commercial wind turbine installations now approaching their end of life, the problem of blade disposal is just beginning to emerge as a significant factor for the future. This paper is aimed at discovering the magnitude of the wind turbine blade waste problem, looking not only at disposal but at all stages of a blade's lifecycle. The first stage of the research, the subject of this paper, is to accurately estimate present and future wind turbine blade waste inventory using the most recent and most accurate data available. The result will provide a solid reference point to help the industry and policy makers to understand the size of potential environmental problem and to help to manage it better. This study starts by estimating the annual blade material usage with wind energy installed capacity and average blade weight. The effect of other waste contributing factors in the full lifecycle of wind turbine blades is then included, using industrial data from the manufacturing, testing and in-service stages. The research indicates that there will be 43 million tonnes of blade waste worldwide by 2050 with China possessing 40% of the waste, Europe 25%, the United States 16% and the rest of the world 19%. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

  8. Wireless Inductive Power Device Suppresses Blade Vibrations

    Science.gov (United States)

    Morrison, Carlos R.; Provenza, Andrew J.; Choi, Benjamin B.; Bakhle, Milind A.; Min, James B.; Stefko, George L.; Duffy, Kirsten P.; Fougers, Alan J.

    2011-01-01

    Vibration in turbomachinery can cause blade failures and leads to the use of heavier, thicker blades that result in lower aerodynamic efficiency and increased noise. Metal and/or composite fatigue in the blades of jet engines has resulted in blade destruction and loss of lives. Techniques for suppressing low-frequency blade vibration, such as gtuned circuit resistive dissipation of vibratory energy, h or simply "passive damping," can require electronics incorporating coils of unwieldy dimensions and adding unwanted weight to the rotor. Other approaches, using vibration-dampening devices or damping material, could add undesirable weight to the blades or hub, making them less efficient. A wireless inductive power device (WIPD) was designed, fabricated, and developed for use in the NASA Glenn's "Dynamic Spin Rig" (DSR) facility. The DSR is used to simulate the functionality of turbomachinery. The relatively small and lightweight device [10 lb (approx.=4.5 kg)] replaces the existing venerable and bulky slip-ring. The goal is the eventual integration of this technology into actual turbomachinery such as jet engines or electric power generators, wherein the device will facilitate the suppression of potentially destructive vibrations in fan blades. This technology obviates slip rings, which require cooling and can prove unreliable or be problematic over time. The WIPD consists of two parts: a remote element, which is positioned on the rotor and provides up to 100 W of electrical power to thin, lightweight piezoelectric patches strategically placed on/in fan blades; and a stationary base unit that wirelessly communicates with the remote unit. The base unit supplies inductive power, and also acts as an input and output corridor for wireless measurement, and active control command to the remote unit. Efficient engine operation necessitates minimal disturbance to the gas flow across the turbine blades in any effort to moderate blade vibration. This innovation makes it

  9. Methodology for wind turbine blade geometry optimization

    Energy Technology Data Exchange (ETDEWEB)

    Perfiliev, D.

    2013-11-01

    Nowadays, the upwind three bladed horizontal axis wind turbine is the leading player on the market. It has been found to be the best industrial compromise in the range of different turbine constructions. The current wind industry innovation is conducted in the development of individual turbine components. The blade constitutes 20-25% of the overall turbine budget. Its optimal operation in particular local economic and wind conditions is worth investigating. The blade geometry, namely the chord, twist and airfoil type distributions along the span, responds to the output measures of the blade performance. Therefore, the optimal wind blade geometry can improve the overall turbine performance. The objectives of the dissertation are focused on the development of a methodology and specific tool for the investigation of possible existing wind blade geometry adjustments. The novelty of the methodology presented in the thesis is the multiobjective perspective on wind blade geometry optimization, particularly taking simultaneously into account the local wind conditions and the issue of aerodynamic noise emissions. The presented optimization objective approach has not been investigated previously for the implementation in wind blade design. The possibilities to use different theories for the analysis and search procedures are investigated and sufficient arguments derived for the usage of proposed theories. The tool is used for the test optimization of a particular wind turbine blade. The sensitivity analysis shows the dependence of the outputs on the provided inputs, as well as its relative and absolute divergences and instabilities. The pros and cons of the proposed technique are seen from the practical implementation, which is documented in the results, analysis and conclusion sections. (orig.)

  10. 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.

  11. A novel folding blade of wind turbine rotor for effective power control

    International Nuclear Information System (INIS)

    Xie, Wei; Zeng, Pan; Lei, Liping

    2015-01-01

    Highlights: • A novel folding blade for wind turbine power control is proposed. • Wind tunnel experiments were conducted to analyze folding blade validity. • Folding blade is valid to control wind turbine power output. • Compared to pitch control, thrust was reduced by fold control in power regulation. • Optimum fold angles were found for wind turbine start up and aerodynamic brake. - Abstract: A concept of novel folding blade of horizontal axis wind turbine is proposed in current study. The folding blade comprises a stall regulated root blade section and a folding tip blade section with the fold axis inclined relative to blade span. By folding blade, lift force generated on the tip blade section changes and the moment arm also shortens, which leads to variations of power output. The blade folding actuation mechanism with servo motor and worm-gear reducer was designed. Wind turbine rotor control scheme and servo system with double feedback loops for blade fold angle control were proposed. In this study, a small folding blade model was tested in a wind tunnel to analyze its performance. The blade model performance was estimated in terms of rotation torque coefficient and thrust coefficient. Wind tunnel experiments were also conducted for pitch control using the same blade model in order to make a direct comparison. The power control, start up and aerodynamic brake performance of the folding blade were analyzed. According to the wind tunnel experiment results, fold angle magnitude significantly affected blade aerodynamic performance and the thrust characteristic together with the rotation torque characteristic of folding blade were revealed. The experiment results demonstrated that the folding blade was valid to control power output and had advantages in reducing thrust with maximum reduction of 51.1% compared to pitch control. Optimum fold angles of 55° and 90° were also found for start up and aerodynamic brake, respectively

  12. Research on the nonintrusive measurement of the turbine blade vibration

    Science.gov (United States)

    Zhang, Shi hai; Li, Lu-ping; Rao, Hong-de

    2008-11-01

    It's one of the important ways to monitor the change of dynamic characteristic of turbine blades for ensuring safety operation of turbine unit. Traditional measurement systems for monitoring blade vibration generally use strain gauges attached to the surface of turbine blades, each strain gauge gives out an analogue signal related to blade deformation, it's maximal defect is only a few blades could be monitored which are attached by strain gauge. But the noncontact vibration measurement will be discussed would solve this problem. This paper deals with noncontact vibration measurement on the rotor blades of turbine through experiments. In this paper, the noncontact vibration measurement - Tip Timing Measurement will be presented, and will be improved. The statistics and DFT will be used in the improved measurement. The main advantage of the improved measurement is that only two sensors over the top of blades and one synchronous sensor of the rotor are used to get the exact vibration characteristics of the each blade in a row. In our experiment, we adopt NI Company's DAQ equipment: SCXI1001 and PCI 6221, three optical sensors, base on the graphics program soft LabVIEW to develop the turbine blade monitor system. At the different rotational speed of the rotor (1000r/m and 1200r/m) we do several experiments on the bench of the Turbine characteristic. Its results indicated that the vibration of turbine blade could be real-time monitored and accurately measured by the improved Tip Timing Measurement.

  13. Unit root tests for cross-sectionally dependent panels : The influence of observed factors

    NARCIS (Netherlands)

    Becheri, I.G.; Drost, F.C.; van den Akker, R.

    This paper considers a heterogeneous panel unit root model with cross-sectional dependence generated by a factor structure—the factor common to all units being an observed covariate. The model is shown to be Locally Asymptotically Mixed Normal (LAMN), with the random part of the limiting Fisher

  14. Family of airfoil shapes for rotating blades. [for increased power efficiency and blade stability

    Science.gov (United States)

    Noonan, K. W. (Inventor)

    1983-01-01

    An airfoil which has particular application to the blade or blades of rotor aircraft such as helicopters and aircraft propellers is described. The airfoil thickness distribution and camber are shaped to maintain a near zero pitching moment coefficient over a wide range of lift coefficients and provide a zero pitching moment coefficient at section Mach numbers near 0.80 and to increase the drag divergence Mach number resulting in superior aircraft performance.

  15. Flow characteristics in nuclear steam turbine blade passage

    International Nuclear Information System (INIS)

    Ahn, H.J.; Yoon, W.H.; Kwon, S.B.

    1995-01-01

    The rapid expansion of condensable gas such as moist air or steam gives rise to nonequilibrium condensation. As a result of irreversibility of condensation process in the nuclear steam turbine blade passage, the entropy of the flow increases, and the efficiency of the turbine decreases. In the present study, in order to investigate the flow characteristics of moist air in two-dimensional turbine blade passage which is made from the configuration of the last stage tip section of the actual nuclear steam turbine moving blade, the static pressures along both pressure and suction sides of blade are measured by static pressure taps and the distribution of Mach number on both sides of the blade are obtained by using the measured static pressure. Also, the flow field is visualized by a Schlieren system. From the experimental results, the effects of the stagnation temperature and specific humidity on the flow properties in the two dimensional steam turbine blade passage are clearly identified

  16. Methodology for Structural Integrity Analysis of Gas Turbine Blades

    Directory of Open Access Journals (Sweden)

    Tiago de Oliveira Vale

    2012-03-01

    Full Text Available One of the major sources of stress arising in turbomachinery blades are the centrifugal loads acting at any section of the airfoil. Accounting for this phenomenon stress evaluation of the blade attachment region in the disc has to be performed in order to avoid blade failure. Turbomachinery blades are generally twisted, and the cross section area varies from the root of the blade to the tip. The blade root shape at the attachment region is of great concern. Stress concentrations are predictable at this contact region. In this paper, a finite element model has been created for the purpose of assessing stress at the joint region connecting the blade to the disc slot. Particular attention was paid to the geometric modeling of the "fir-tree" fixing, which is now used in the majority of gas turbine engines. This study has been performed using the commercial software ANSYS 13.0. The disc and blade assembly are forced to move with a certain rotational velocity. Contact connections are predicted on the common faces of the blade and on the disc at the root. Solutions can be obtained to allow the evaluation of stresses. Results can be compared with the mechanical properties of the adopted material.

  17. 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.

  18. 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....

  19. Blade attachment assembly

    Science.gov (United States)

    Garcia-Crespo, Andres Jose; Delvaux, John McConnell; Miller, Diane Patricia

    2016-05-03

    An assembly and method for affixing a turbomachine rotor blade to a rotor wheel are disclosed. In an embodiment, an adaptor member is provided disposed between the blade and the rotor wheel, the adaptor member including an adaptor attachment slot that is complementary to the blade attachment member, and an adaptor attachment member that is complementary to the rotor wheel attachment slot. A coverplate is provided, having a coverplate attachment member that is complementary to the rotor wheel attachment slot, and a hook for engaging the adaptor member. When assembled, the coverplate member matingly engages with the adaptor member, and retains the blade in the adaptor member, and the assembly in the rotor wheel.

  20. Managed care market share and cesarean section rates in the United States: is there a link?

    Science.gov (United States)

    Hueston, W J; Sutton, A

    2000-11-01

    After peaking during the early 1980s, cesarean section rates in the United States have been falling for the last decade. At the same time, managed care enrollment has increased dramatically. This study examines whether managed care penetration in local markets is associated with lower cesarean section rates in those geographic area. A cross-sectional comparison of cesarean section rates and health maintenance organization (HMO) market penetration in 61 selected metropolitan areas in the United States was conducted. National birth certificate data for 1996 were used to calculate crude and race-adjusted cesarean section rates for residents in each area. No relationship between overall cesarean section rates in the metropolitan areas and managed care penetration was observed. Subanalyses of racial groups demonstrated the existence of a weak association between managed care penetration and cesarean section rates for white women (21.2% for the highest quartile of HMO penetration, compared with 19.1% for the lowest quartile; P = .03), but not for African-Americans or other minorities. Managed care penetration in a market may have an association with cesarean section rates for white women, but the strength of this relationship is small. Even if managed care delivery systems reduce cesarean section rates in their own populations, this change is likely to have only a small impact on overall cesarean rates. HMO penetration is unlikely to influence national cesarean section rates, nor does it appear to explain state variations in these rates.

  1. Associations among unit leadership and unit climates for implementation in acute care: a cross-sectional study.

    Science.gov (United States)

    Shuman, Clayton J; Liu, Xuefeng; Aebersold, Michelle L; Tschannen, Dana; Banaszak-Holl, Jane; Titler, Marita G

    2018-04-25

    Nurse managers have a pivotal role in fostering unit climates supportive of implementing evidence-based practices (EBPs) in care delivery. EBP leadership behaviors and competencies of nurse managers and their impact on practice climates are widely overlooked in implementation science. The purpose of this study was to examine the contributions of nurse manager EBP leadership behaviors and nurse manager EBP competencies in explaining unit climates for EBP implementation in adult medical-surgical units. A multi-site, multi-unit cross-sectional research design was used to recruit the sample of 24 nurse managers and 553 randomly selected staff nurses from 24 adult medical-surgical units from 7 acute care hospitals in the Northeast and Midwestern USA. Staff nurse perceptions of nurse manager EBP leadership behaviors and unit climates for EBP implementation were measured using the Implementation Leadership Scale and Implementation Climate Scale, respectively. EBP competencies of nurse managers were measured using the Nurse Manager EBP Competency Scale. Participants were emailed a link to an electronic questionnaire and asked to respond within 1 month. The contributions of nurse manager EBP leadership behaviors and competencies in explaining unit climates for EBP implementation were estimated using mixed-effects models controlling for nurse education and years of experience on current unit and accounting for the variability across hospitals and units. Significance level was set at α < .05. Two hundred sixty-four staff nurses and 22 nurse managers were included in the final sample, representing 22 units in 7 hospitals. Nurse manager EBP leadership behaviors (p < .001) and EBP competency (p = .008) explained 52.4% of marginal variance in unit climate for EBP implementation. Leadership behaviors uniquely explained 45.2% variance. The variance accounted for by the random intercepts for hospitals and units (p < .001) and years of nursing experience in current unit

  2. Construction of low-cost, Mod-OA wood composite wind turbine blades

    Science.gov (United States)

    Lark, R. F.

    1983-01-01

    Two sixty-foot, low-cost, wood composite blades for service on 200 kW Mod-OA wind turbines were constructed. The blades were constructed of epoxy resin-bonded Douglas fir veneers for the leading edge sections, and paper honeycombcored, birch plywood faced panels for the afterbody sections. The blades were joined to the wind turbine hub by epoxy resin-bonded steel load take-off studs embedded into the root end of the blades. The blades were installed on the 200 kW Mod-OA wind turbine facility at Kahuku, Hawaii, The blades completed nearly 8,000 hours of operation over an 18 month period at an average power of 150 kW prior to replacement with another set of wood composite blades. The blades were replaced because of a corrosion failure of the steel shank on one stud. Inspections showed that the wood composite structure remained in excellent condition.

  3. Evaluation of feasibility of prestressed concrete for use in wind turbine blades

    Science.gov (United States)

    Leiblein, S.; Londahl, D. S.; Furlong, D. B.; Dreier, M. E.

    1979-01-01

    A preliminary evaluation of the feasibility of the use of prestressed concrete as a material for low cost blades for wind turbines was conducted. A baseline blade design was achieved for an experimental wind turbine that met aerodynamic and structural requirements. Significant cost reductions were indicated for volume production. Casting of a model blade section showed no fabrication problems. Coupled dynamic analysis revealed that adverse rotor tower interactions can be significant with heavy rotor blades.

  4. Structural health monitoring of wind turbine blades

    Science.gov (United States)

    Rumsey, Mark A.; Paquette, Joshua A.

    2008-03-01

    As electric utility wind turbines increase in size, and correspondingly, increase in initial capital investment cost, there is an increasing need to monitor the health of the structure. Acquiring an early indication of structural or mechanical problems allows operators to better plan for maintenance, possibly operate the machine in a de-rated condition rather than taking the unit off-line, or in the case of an emergency, shut the machine down to avoid further damage. This paper describes several promising structural health monitoring (SHM) techniques that were recently exercised during a fatigue test of a 9 meter glass-epoxy and carbon-epoxy wind turbine blade. The SHM systems were implemented by teams from NASA Kennedy Space Center, Purdue University and Virginia Tech. A commercial off-the-shelf acoustic emission (AE) NDT system gathered blade AE data throughout the test. At a fatigue load cycle rate around 1.2 Hertz, and after more than 4,000,000 fatigue cycles, the blade was diagnostically and visibly failing at the out-board blade spar-cap termination point at 4.5 meters. For safety reasons, the test was stopped just before the blade completely failed. This paper provides an overview of the SHM and NDT system setups and some current test results.

  5. Design of a 21 m blade with Risø-A1 airfoils for active stall controlled wind turbines

    DEFF Research Database (Denmark)

    Fuglsang, Peter; Sangill, O.; Hansen, P.

    2002-01-01

    This is the final report, from the project, "Design of a Rotor/Airfoil Family for Active Stall-regulated Wind Turbines by Use of Multi-point Optimization". It describes the full scale testing of a 21 m wind turbine blade specially designed for active stallregulation. Design objectives were...... increased ratio of produced energy to turbine loads and more stable power control characteristics. Both were taken directly into account during the design of the blade using numerical optimization. The blade used theRisø-A1 airfoil family, which was specially designed for operation on wind turbine blades....... The new blade was designed to replace the LM 21.0P blade. A measurement campaign was carried out simultaneously on two identical adjacent wind turbines where onehad the new blades and the other had LM 21.0P blades. Power and loads including blade section moments for the new blades were measured to assess...

  6. Ceramic blade attachment system

    Science.gov (United States)

    Frey, G.A.; Jimenez, O.D.

    1996-12-03

    A turbine blade having a preestablished rate of thermal expansion is attached to a turbine flange having a preestablished rate of thermal expansion being greater than the preestablished rate of thermal expansion of the turbine blade. The turbine flange includes a first upstanding flange and a second upstanding flange having a groove formed between them. The turbine flange further includes a recess. Each of the first and second upstanding flanges have a plurality of bores therein. A turbine blade has a first member and a second member positioned in one of the groove and the recess. Each of the first member and the second member have a plurality of bores therein. A pin is positioned in respective ones of the plurality of bores in the first and second upstanding members and the first and second members and attach the blade to the turbine flange. The pin has a preestablished rate of thermal expansion being substantially equal to the rate of thermal expansion of the blade. 4 figs.

  7. Discussion paper on managing composite blade waste

    DEFF Research Database (Denmark)

    Skelton, Kristen

    A sustainable process for dealing with wind turbines at the end of their service life is needed in order to maximize the environmental benefits of wind power from a life cycle approach. Most components of a wind turbine such as foundation, tower, components of the gear box and generator are alrea...... as practical examples and experiences from research and industry projects. Important sources have been obtained from researchers, the original equipment manufacturers (OEMs), operators and maintainers (O&Ms), waste handlers and those that use the recyclates from blade waste....... recyclable and treated accordingly. Nevertheless, wind turbine blades represent a challenge due to the materials used and their complex composition. The objective of this research note is to provide an overview of the different methods used for sectioning and recycling wind turbine blades as well...

  8. Experimental Investigation of Inter-Blade Vortices in a Model Francis Turbine

    Science.gov (United States)

    LIU, Demin; LIU, Xiaobing; ZHAO, Yongzhi

    2017-07-01

    The inter-blade vortex in a Francis turbine becomes one of the main hydraulic factors that are likely to cause blade erosion at deep part load operating conditions. However, the causes and the mechanism of inter-blade vortex are still under investigation according to present researches. Thus the causes of inter-blade vortex and the effect of different hydraulic parameters on the inter-blade vortex are investigated experimentally. The whole life cycle of the inter-blade vortex is observed by a high speed camera. The test results illustrate the whole life cycle of the inter-blade vortex from generation to separation and even to fading. It is observed that the inter-blade vortex becomes stronger with the decreasing of flow and head, which leads to pressure fluctuation. Meanwhile, the pressure fluctuations in the vane-less area and the draft tube section become stronger when inter-blade vortices exist in the blade channel. The turbine will be damaged if operating in the inter-blade vortex zone, so its operating range must be far away from that zone. This paper reveals the main cause of the inter-blade vortex which is the larger incidence angle between the inflow angle and the blade angle on the leading edge of the runner at deep part load operating conditions.

  9. Compressor blade setting angle accuracy study, volume 1

    Science.gov (United States)

    Holman, F. F.; Kidwell, J. R.

    1976-01-01

    The aerodynamic test of a small, single stage, highly loaded, axial flow transonic compressor is covered. The stage was modified by fabricating a 24 blade rotor with mis-set blades in a repeating pattern - two degrees closed from nominal, two degrees open from nominal and nominal. The unit was instrumented to determine overall performance and average blade element data. High-response, dynamic pressure probes were installed to record pressure patterns at selected points in the flowpath. Testing was conducted at speeds from 70 to 94% of design equivalent speed with a conventional casing and also with circumferential grooves over the rotor tip. Testing indicated severe performance penalties were incurred as a result of the mis-set blading. Lower flow, pressure ratio, and efficiency were observed for the stage with or without casing treatment. Periodic pressure variations were detected at every location where high response pressure sensors were located and were directly related to blading geometry.

  10. Changes in patient safety culture after restructuring of intensive care units: Two cross-sectional studies.

    Science.gov (United States)

    Vifladt, Anne; Simonsen, Bjoerg O; Lydersen, Stian; Farup, Per G

    2016-02-01

    Compare changes in registered nurses' perception of the patient safety culture in restructured and not restructured intensive care units during a four-year period. Two cross-sectional surveys were performed, in 2008/2009 (time 1) and 2012/2013 (time 2). During a period of 0-3 years after time 1, three of six hospitals merged their general and medical intensive care units (restructured). The other hospitals maintained their structure of the intensive care units (not restructured). Intensive care units in hospitals at one Norwegian hospital trust. The safety culture was measured with Hospital Survey on Patient Safety Culture. At times 1 and 2, 217/302 (72%) and 145/289 (50%) registered nurses participated. Restructuring was negatively associated with change in the safety culture, in particular, the dimensions of the safety culture within the unit level. The dimensions most vulnerable for restructuring were manager expectations and actions promoting safety, teamwork within hospital units and staffing. In this study, the restructuring of intensive care units was associated with a negative impact on the safety culture. When restructuring, the management should be particularly aware of changes in the safety culture dimensions manager expectations and actions promoting safety, teamwork within hospital units and staffing. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  11. Mitigation of FOD and Corrosion Fatigue Damage in 17-4 PH Stainless Steel Compressor Blades With Surface Treatment

    National Research Council Canada - National Science Library

    Prevey, Paul S; Jayaraman, N; Ravindranath, Ravi

    2004-01-01

    ... the geometrical conditions of thick section and blade leading edges of compressor blades. The FOD tolerance and corrosion fatigue performance of 17-4PH prepared by low plasticity burnishing (LPB), shot peening (SP...

  12. A blade deflection monitoring system

    DEFF Research Database (Denmark)

    2017-01-01

    A wind turbine blade comprising a system for monitoring the deflection of a wind turbine blade is described. The system comprises a wireless range-measurement system, having at least one wireless communication device located towards the root end of the blade and at least one wireless communication...

  13. Reduction of wind powered generator cost by use of a one bladed rotor

    Energy Technology Data Exchange (ETDEWEB)

    Pruyn, R R; Wiesner, W; Ljungstroem, O [ed.

    1976-01-01

    Cost analysis supported by preliminary design studies of one and two bladed wind powered generator units shows that a 30% reduction in acquisition cost can be achieved with a one bladed design. Designs studied were sized for an output power of 1000 kilowatts. The one bladed design has the potential for reducing acquisition cost to $680 per available kilowatt if the unit is located in a region with mean surface winds of 15 mph. Vibratory loads of the one bladed design are significant and will require considerable design attention. The one per rev Coriolis torque caused by blade flapping is the most significant problem. The major source of blade flapping will be the velocity gradient of the ground boundary layer. A torsional vibration isolating coupling may be required in the generator drive to reduce the loads due to this vibratory torque. An inclined flapping hinge also is desirable to cause pitch-flap coupling that will suppress blade flap motions.

  14. 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.

  15. Database about blade faults

    DEFF Research Database (Denmark)

    Branner, Kim; Ghadirian, Amin

    This report deals with the importance of measuring the reliability of the rotor blades and describing how they can fail. The Challenge is that very little non-confidential data is available and that the quality and detail in the data is limited....

  16. BWR control blade replacement strategies

    Energy Technology Data Exchange (ETDEWEB)

    Kennard, M W [Stoller Nuclear Fuel, NAC International, Pleasantville, NY (United States); Harbottle, J E [Stoller Nuclear Fuel, NAC International, Thornbury, Bristol (United Kingdom)

    2000-02-01

    The reactivity control elements in a BWR, the control blades, perform three significant functions: provide shutdown margin during normal and accident operating conditions; provide overall core reactivity control; and provide axial power shaping control. As such, the blades are exposed to the core's neutron flux, resulting in irradiation of blade structural and absorber materials. Since the absorber depletes with time (if B{sub 4}C is used, it also swells) and the structural components undergo various degradation mechanisms (e.g., embrittlement, corrosion), the blades have limits on their operational lifetimes. Consequently, BWR utilities have implemented strategies that aim to maximize blade lifetimes while balancing operational costs, such as extending a refuelling outage to shuffle high exposure blades. This paper examines the blade replacement strategies used by BWR utilities operating in US, Europe and Asia by assembling information related to: the utility's specific blade replacement strategy; the impact the newer blade designs and changes in core operating mode were having on those strategies; the mechanical and nuclear limits that determined those strategies; the methods employed to ensure that lifetime limits were not exceeded during operation; and blade designs used (current and replacement blades). (author)

  17. BWR control blade replacement strategies

    International Nuclear Information System (INIS)

    Kennard, M.W.; Harbottle, J.E.

    2000-01-01

    The reactivity control elements in a BWR, the control blades, perform three significant functions: provide shutdown margin during normal and accident operating conditions; provide overall core reactivity control; and provide axial power shaping control. As such, the blades are exposed to the core's neutron flux, resulting in irradiation of blade structural and absorber materials. Since the absorber depletes with time (if B 4 C is used, it also swells) and the structural components undergo various degradation mechanisms (e.g., embrittlement, corrosion), the blades have limits on their operational lifetimes. Consequently, BWR utilities have implemented strategies that aim to maximize blade lifetimes while balancing operational costs, such as extending a refuelling outage to shuffle high exposure blades. This paper examines the blade replacement strategies used by BWR utilities operating in US, Europe and Asia by assembling information related to: the utility's specific blade replacement strategy; the impact the newer blade designs and changes in core operating mode were having on those strategies; the mechanical and nuclear limits that determined those strategies; the methods employed to ensure that lifetime limits were not exceeded during operation; and blade designs used (current and replacement blades). (author)

  18. About the problems and perspectives of making precision compressor blades

    Directory of Open Access Journals (Sweden)

    V. E. Galiev

    2014-01-01

    Full Text Available The problems of manufacturing blades with high precision profile geometry are considered in the article. The variant of the technology under development rules out the use of mechanical processing methods for blades airfoil. The article consists of an introduction and six small sections.The introduction sets out the requirements for modern aircraft engines, makes a list of problems arisen in the process of their manufacturing, and marks the relevance of the work.The first section analyzes the existing technology of precision blades. There is an illustration reflecting the stages of the process. Their advantages and disadvantages are marked.The second section provides an illustration, which shows the system-based blades used in the manufacturing process and a model of the work piece using the technology being developed. An analysis of each basing scheme is presented.In the third section we list the existing control methods of geometrical parameters of blades airfoil and present the measurement error data of devices. The special attention is paid to the impossibility to control the accuracy of geometrical parameters of precision blades.The fourth section presents the advantages of the electrochemical machining method with a consistent vibration of tool-electrode and with feeding the pulses of technology current over the traditional method. The article presents data accuracy and surface roughness of the blades airfoil reached owing to precision electrochemical machining. It illustrates machines that implement the given method of processing and components manufactured on them.The fifth section describes the steps of the developed process with justification for the use of the proposed operations.Based on the analysis, the author argues that the application of the proposed process to manufacture the precision compressor blades ensures producing the items that meet the requirements of the drawing.

  19. Study of Track Irregularity Time Series Calibration and Variation Pattern at Unit Section

    Directory of Open Access Journals (Sweden)

    Chaolong Jia

    2014-01-01

    Full Text Available Focusing on problems existing in track irregularity time series data quality, this paper first presents abnormal data identification, data offset correction algorithm, local outlier data identification, and noise cancellation algorithms. And then proposes track irregularity time series decomposition and reconstruction through the wavelet decomposition and reconstruction approach. Finally, the patterns and features of track irregularity standard deviation data sequence in unit sections are studied, and the changing trend of track irregularity time series is discovered and described.

  20. Testing for Unit Roots in Small Panels with Short-run and Long-run Cross-sectional Dependencies

    OpenAIRE

    Yoosoon Chang; Wonho Song

    2009-01-01

    An IV approach, using as instruments non-linear transformations of the lagged levels, is explored to test for unit roots in panels with general dependency and heterogeneity across cross-sectional units. We allow not only for the cross-sectional dependencies of innovations, but also for the presence of co-integration across cross-sectional levels. Unbalanced panels and panels with differing individual short-run dynamics and cross-sectionally related dynamics are also permitted. We also more ca...

  1. 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

  2. Design and evaluation of low-cost laminated wood composite blades for intermediate size wind turbines: Blade design, fabrication concept, and cost analysis

    Science.gov (United States)

    Lieblein, S.; Gaugeon, M.; Thomas, G.; Zueck, M.

    1982-01-01

    As part of a program to reduce wind turbine costs, an evaluation was conducted of a laminated wood composite blade for the Mod-OA 200 kW wind turbine. The effort included the design and fabrication concept for the blade, together with cost and load analyses. The blade structure is composed of laminated Douglas fir veneers for the primary spar and nose sections, and honeycomb cored plywood panels for the trailing edges sections. The attachment of the wood blade to the rotor hub was through load takeoff studs bonded into the blade root. Tests were conducted on specimens of the key structural components to verify the feasibility of the concept. It is concluded that the proposed wood composite blade design and fabrication concept is suitable for Mod-OA size turbines (125-ft diameter rotor) at a cost that is very competitive with other methods of manufacture.

  3. Graphene in turbine blades

    Science.gov (United States)

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

    2016-07-01

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

  4. Subsonic Swept Fan Blade

    Science.gov (United States)

    Gallagher, Edward J. (Inventor); Rogers, Thomas H. (Inventor)

    2017-01-01

    A gas turbine engine includes a spool, a turbine coupled to drive the spool, a propulsor coupled to be driven at a at a design speed by the turbine through the spool, and a gear assembly coupled between the propulsor and the spool. Rotation of the turbine drives the propulsor at a different speed than the spool. The propulsor includes a hub and a row of propulsor blades that extend from the hub. Each of the propulsor blades includes an airfoil body. The leading edge of the airfoil body has a swept profile such that, at the design speed, a component of a relative velocity vector of a working gas that is normal to the leading edge is subsonic along the entire radial span.

  5. Laser-based gluing of diamond-tipped saw blades

    Science.gov (United States)

    Hennigs, Christian; Lahdo, Rabi; Springer, André; Kaierle, Stefan; Hustedt, Michael; Brand, Helmut; Wloka, Richard; Zobel, Frank; Dültgen, Peter

    2016-03-01

    To process natural stone such as marble or granite, saw blades equipped with wear-resistant diamond grinding segments are used, typically joined to the blade by brazing. In case of damage or wear, they must be exchanged. Due to the large energy input during thermal loosening and subsequent brazing, the repair causes extended heat-affected zones with serious microstructure changes, resulting in shape distortions and disadvantageous stress distributions. Consequently, axial run-out deviations and cutting losses increase. In this work, a new near-infrared laser-based process chain is presented to overcome the deficits of conventional brazing-based repair of diamond-tipped steel saw blades. Thus, additional tensioning and straightening steps can be avoided. The process chain starts with thermal debonding of the worn grinding segments, using a continuous-wave laser to heat the segments gently and to exceed the adhesive's decomposition temperature. Afterwards, short-pulsed laser radiation removes remaining adhesive from the blade in order to achieve clean joining surfaces. The third step is roughening and activation of the joining surfaces, again using short-pulsed laser radiation. Finally, the grinding segments are glued onto the blade with a defined adhesive layer, using continuous-wave laser radiation. Here, the adhesive is heated to its curing temperature by irradiating the respective grinding segment, ensuring minimal thermal influence on the blade. For demonstration, a prototype unit was constructed to perform the different steps of the process chain on-site at the saw-blade user's facilities. This unit was used to re-equip a saw blade with a complete set of grinding segments. This saw blade was used successfully to cut different materials, amongst others granite.

  6. Performance of Savonius Blade Waterwheel with Variation of Blade Number

    Science.gov (United States)

    Sule, L.; Rompas, P. T. D.

    2018-02-01

    The utilization of water energy source is mainly used as a provider of electrical energy through hydroelectric power. The potential utilization of water flow energy is relatively small. The objective of this study is to know the best blade of Savonius waterwheel with various variables such as water discharge, blade number, and loading. The data used the efficiency of waterwheel, variation of blade number, variable water discharge, and loading in the shaft. The test results have shown that the performances of a top-water mill with the semicircular curve where the variation in the number of blades are 4, 6, and 8 at discharge and loading of 0.01587 m3/s and 1000 grams respectively were 9.945%, 13.929%, and 17.056% respectively. The blades number of 8 obtained the greatest performance. The more number of blades the greater the efficiency of the waterwheel Savonius.

  7. Investigation of Structural Behavior due to Bend-Twist Couplings in Wind Turbine Blades

    DEFF Research Database (Denmark)

    Fedorov, Vladimir; Dimitrov, Nikolay Krasimirov; Berggreen, Christian

    2010-01-01

    for predicting the torsional response of the wind turbine blades with built-in bend-twist couplings. Additionally, a number of improved full-scale tests using an advanced bi-axial servo-hydraulic load control have been performed on a wind turbine blade section provided by Vestas Wind Systems A/S. In the present......One of the problematic issues concerning the design of future large composite wind turbine blades is the prediction of bend-twist couplings and torsion behaviour. The current work is a continuation of a previous work [1,2], and it examines different finite element modelling approaches...... of the blade cross section as the defining surface, off-setting the location of the shell elements according to the specified thickness. The experimental full-scale tests were carried out on an 8 m section of a 23 m wind turbine blade with specially implemented bend-twist coupling. The blade was tested under...

  8. Standard Specification for Steel Blades Used with the Photovoltaic Module Surface Cut Test

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2009-01-01

    1.1 This specification specifies the recommended physical characteristics of the steel blades required for the surface cut test described in ANSI/UL 1703 (Section 24) and IEC 61730-2 (Paragraph 10.3). 1.2 ANSI/UL 1703 and IEC 61730-2 are standards for photovoltaic module safety testing. 1.3 This standard provides additional fabrication details for the surface cut test blades that are not provided in ANSI/UL 1703 or IEC 61730-2. Surface cut test blades that have out-of-tolerance corner radii or burrs are known to cause erroneous test results, either passes or failures. 1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.5 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  9. Techniques for blade tip clearance measurements with capacitive probes

    Science.gov (United States)

    Steiner, Alexander

    2000-07-01

    This article presents a proven but advantageous concept for blade tip clearance evaluation in turbomachinery. The system is based on heavy duty probes and a high frequency (HF) and amplifying electronic unit followed by a signal processing unit. Measurements are taken under high temperature and other severe conditions such as ionization. Every single blade can be observed. The signals are digitally filtered and linearized in real time. The electronic set-up is highly integrated. Miniaturized versions of the electronic units exist. The small and robust units can be used in turbo engines in flight. With several probes at different angles in one radial plane further information is available. Shaft eccentricity or blade oscillations can be calculated.

  10. Improved simulation design factors for unconventional crude vacuum units : cracked gas make and stripping section performance

    Energy Technology Data Exchange (ETDEWEB)

    Remesat, D. [Koch-Glitsch Canada LP, Calgary, AB (Canada)

    2008-10-15

    Operating data for unconventional heavy oil vacuum crude units were reviewed in order to optimize the design of vacuum columns. Operational data from heavy crude vacuum units operating with stripping and velocity were used to investigate the application of a proven vacuum distillation tower simulation topology designed for use with heavy oil and bitumen upgrader feeds. Design factors included a characterization of the crude oils or bitumens processed in the facility; the selection of thermodynamic models; and the non-equilibrium simulation topology. Amounts of generated cracked gas were calculated, and entrainment and stripping section performance was evaluated. Heater designs for ensuring the even distribution of heat flux were discussed. Data sets from vacuum units processing crude oils demonstrated that the amount of offgas flow increased as the transfer line temperature increased. The resulting instability caused increased coke generation and light hydrocarbon formation. Results also indicated that overhead vacuum ejector design and size as well as heat transfer capabilities of quench and pumparound zones must be considered when designing vacuum column units. Steam stripping lowered hydrocarbon partial pressure to allow materials to boil at lower temperatures. It was concluded that setting appropriate entrainment values will ensure the accuracy of sensitivity analyses for transfer line designs, inlet feed devices, and wash bed configurations. 9 refs., figs.

  11. Ceramic blade with tip seal

    Science.gov (United States)

    Glezer, B.; Bhardwaj, N.K.; Jones, R.B.

    1997-08-05

    The present gas turbine engine includes a disc assembly defining a disc having a plurality of blades attached thereto. The disc has a preestablished rate of thermal expansion and the plurality of blades have a preestablished rate of thermal expansion being less than the preestablished rate of thermal expansion of the disc. A shroud assembly is attached to the gas turbine engine and is spaced from the plurality of blades a preestablished distance forming an interface there between. Positioned in the interface is a seal having a preestablished rate of thermal expansion being generally equal to the rate of thermal expansion of the plurality of blades. 4 figs.

  12. The blade element momentum (BEM) method

    DEFF Research Database (Denmark)

    Branlard, Emmanuel Simon Pierre

    2017-01-01

    The current chapter presents the blade element momentum (BEM) method. The BEM method for a steady uniform inflow is presented in a first section. Some of the ad-hoc corrections that are usually added to the algorithm are discussed in a second section. An exception is made to the tip-loss correction...... which is introduced early in the algorithm formulation for practical reasons. The ad-hoc corrections presented are: the tip-loss correction, the high-thrust correction (momentum breakdown) and the correction for wake rotation. The formulation of an unsteady BEM code is given in a third section...

  13. Measurement of Unsteady Aerodynamics Load on the Blade of Field Horizontal Axis Wind Turbine

    Science.gov (United States)

    Kamada, Yasunari; Maeda, Takao; Naito, Keita; Ouchi, Yuu; Kozawa, Masayoshi

    This paper describes an experimental field study of the rotor aerodynamics of wind turbines. The test wind turbine is a horizontal axis wind turbine, or: HAWT with a diameter of 10m. The pressure distributions on the rotating blade are measured with multi point pressure transducers. Sectional aerodynamic forces are analyzed from pressure distribution. Blade root moments are measured simultaneously by a pair of strain gauges. The inflow wind is measured by a three component sonic anemometer, the local inflow of the blade section are measured by a pair of 7 hole Pitot tubes. The relation between the aerodynamic moments on the blade root from pressure distribution and the mechanical moment from strain gauges is discussed. The aerodynamic moments are estimated from the sectional aerodynamic forces and show oscillation caused by local wind speed and direction change. The mechanical moment shows similar oscillation to the aerodynamic excepting the short period oscillation of the blade first mode frequency. The fluctuation of the sectional aerodynamic force triggers resonant blade oscillations. Where stall is present along the blade section, the blade's first mode frequency is dominant. Without stall, the rotating frequency is dominant in the blade root moment.

  14. Prediction of H.A.W.T. blade stall and performance

    Energy Technology Data Exchange (ETDEWEB)

    Giannakidis, G.; Graham, J.M.R. [Imperial College, Dept. of Aeronautics, London (United Kingdom)

    1996-09-01

    A model is being developed for the prediction of Horizontal Axis Wind Turbine blade stall and performance coupled with a simple aeroelastic analysis model. For the aerodynamic calculation a two dimensional unsteady Navier-Stokes solver on a sectional basis on the blade is coupled with a three dimensional vortex lattice wake. Pressure coefficient distributions are calculated from the two dimensional viscous flow in each blade section. The aerodynamic computations are coupled with a vibrating beam model in order to incorporate flapwise deformations of the blade. (au) 17 refs.

  15. Development of a Novel Erosion Resistant Coating System for Use on Rotorcraft Blades

    Science.gov (United States)

    2012-05-01

    Technologies Research Center (UTRC) and Sikorsky utilizes a two part metal/ cermet coating system on the leading edge of the blades to provide unmatched...ARL, United Technologies Research Center (UTRC) and Sikorsky utilizes a two part metal/ cermet coating system on the leading edge of the blades to...Rotor Blade Tip Fairing A study by Ely et.al. evaluated dozens of coating technologies and down-selected a two-part metal/ceramic coating system on

  16. Biodiversity of Aspergillus section Flavi in the United States: a review.

    Science.gov (United States)

    Horn, Bruce W

    2007-10-01

    Fungi belonging to Aspergillus section Flavi are of great economic importance in the United States due to their ability to produce toxic and carcinogenic aflatoxins in agricultural commodities. Development of control strategies against A. flavus and A. parasiticus, the major aflatoxin-producing species, is dependent upon a basic understanding of their diversity in agricultural ecosystems. This review summarizes our current knowledge of species and population diversity in the United States in relation to morphology, mycotoxin production and genetic characters. The high genetic diversity in populations of aflatoxigenic fungi is a reflection of their versatile habits in nature, which include saprotrophic colonization of plant debris in soil and parasitism of seeds and grain. Genetic variation within populations may originate from a cryptic sexual state. The advent of intensive monoculture agriculture not only increases population size but also may introduce positive selective pressure for aflatoxin production due to its link with pathogenicity in crops. Important goals in population research are to determine how section Flavi diversity in agricultural ecosystems is changing and to measure the direction of this evolution.

  17. 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.

  18. Direct Numerical Simulations of a Full Stationary Wind-Turbine Blade

    Science.gov (United States)

    Qamar, Adnan; Zhang, Wei; Gao, Wei; Samtaney, Ravi

    2014-11-01

    Direct numerical simulation of flow past a full stationary wind-turbine blade is carried out at Reynolds number, Re = 10,000 placed at 0 and 5 (degree) angle of attack. The study is targeted to create a DNS database for verification of solvers and turbulent models that are utilized in wind-turbine modeling applications. The full blade comprises of a circular cylinder base that is attached to a spanwise varying airfoil cross-section profile (without twist). An overlapping composite grid technique is utilized to perform these DNS computations, which permits block structure in the mapped computational space. Different flow shedding regimes are observed along the blade length. Von-Karman shedding is observed in the cylinder shaft region of the turbine blade. Along the airfoil cross-section of the blade, near body shear layer breakdown is observed. A long tip vortex originates from the blade tip region, which exits the computational plane without being perturbed. Laminar to turbulent flow transition is observed along the blade length. The turbulent fluctuations amplitude decreases along the blade length and the flow remains laminar regime in the vicinity of the blade tip. The Strouhal number is found to decrease monotonously along the blade length. Average lift and drag coefficients are also reported for the cases investigated. Supported by funding under a KAUST OCRF-CRG grant.

  19. 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...

  20. Integrated circuit cooled turbine blade

    Science.gov (United States)

    Lee, Ching-Pang; Jiang, Nan; Um, Jae Y.; Holloman, Harry; Koester, Steven

    2017-08-29

    A turbine rotor blade includes at least two integrated cooling circuits that are formed within the blade that include a leading edge circuit having a first cavity and a second cavity and a trailing edge circuit that includes at least a third cavity located aft of the second cavity. The trailing edge circuit flows aft with at least two substantially 180-degree turns at the tip end and the root end of the blade providing at least a penultimate cavity and a last cavity. The last cavity is located along a trailing edge of the blade. A tip axial cooling channel connects to the first cavity of the leading edge circuit and the penultimate cavity of the trailing edge circuit. At least one crossover hole connects the penultimate cavity to the last cavity substantially near the tip end of the blade.

  1. Wind Turbine Blade Design System - Aerodynamic and Structural Analysis

    Science.gov (United States)

    Dey, Soumitr

    2011-12-01

    The ever increasing need for energy and the depletion of non-renewable energy resources has led to more advancement in the "Green Energy" field, including wind energy. An improvement in performance of a Wind Turbine will enhance its economic viability, which can be achieved by better aerodynamic designs. In the present study, a design system that has been under development for gas turbine turbomachinery has been modified for designing wind turbine blades. This is a very different approach for wind turbine blade design, but will allow it to benefit from the features inherent in the geometry flexibility and broad design space of the presented system. It starts with key overall design parameters and a low-fidelity model that is used to create the initial geometry parameters. The low-fidelity system includes the axisymmetric solver with loss models, T-Axi (Turbomachinery-AXIsymmetric), MISES blade-to-blade solver and 2D wing analysis code XFLR5. The geometry parameters are used to define sections along the span of the blade and connected to the CAD model of the wind turbine blade through CAPRI (Computational Analysis PRogramming Interface), a CAD neutral API that facilitates the use of parametric geometry definition with CAD. Either the sections or the CAD geometry is then available for CFD and Finite Element Analysis. The GE 1.5sle MW wind turbine and NERL NASA Phase VI wind turbine have been used as test cases. Details of the design system application are described, and the resulting wind turbine geometry and conditions are compared to the published results of the GE and NREL wind turbines. A 2D wing analysis code XFLR5, is used for to compare results from 2D analysis to blade-to-blade analysis and the 3D CFD analysis. This kind of comparison concludes that, from hub to 25% of the span blade to blade effects or the cascade effect has to be considered, from 25% to 75%, the blade acts as a 2d wing and from 75% to the tip 3D and tip effects have to be taken into account

  2. STATISTICAL ANALYSIS OF DAMAGEABILITY OF THE BYPASS ENGINES COMPRESSOR BLADES

    Directory of Open Access Journals (Sweden)

    Boris A. Chichkov

    2018-01-01

    Full Text Available Aircraft gas turbine engines during the operation are exposed to damage of flowing parts. The elements of the engine design, appreciably determining operational characteristics are rotor blades. Character of typical damages for various types of engines depends on appointment and a geographical place of the aircraft operation on which one or another engine is installed. For example, the greatest problem for turboshaft engines operated in the dusty air conditions is erosive wear of a rotor blade airfoil. Among principal causes of flowing parts damages of bypass engine compressors are foreign object damages. Independently there are the damages caused by fatigue of a rotor blade material at dangerous blade mode. Pieces of the ice formed in the input unit, birds and the like can also be a source of danger. The foreign objects getting into the engine from runway are nuts, bolts, pieces of tire protectors, lock-wire, elements from earlier flying off aircraft, etc. The entry of foreign objects into the engine depends on both an operation mode (during the operation on the ground, on takeoff, on landing roll using the reverse and so on, and the aircraft engine position.Thus the foreign objects entered into the flowing path of bypass engine damage blade cascade of low and high pressure. Foreign objects entered into the flowing part of the engine with rotor blades result in dents on edges and blade shroud, deformations of edges, breakage, camber of peripheral parts and are distributed "nonlinear" on path length (steps. The article presents the results of the statistical analysis of three types engine compressors damageability over the period of more than three years. Damages are divided according to types of engines in whole and to their separate steps, depths and lengths, blades damage location. The results of the analysis make it possible to develop recommendations to carry out the optical-visual control procedures.

  3. The Influence of Eroded Blades on Wind Turbine Performance Using Numerical Simulations

    Directory of Open Access Journals (Sweden)

    Matthias Schramm

    2017-09-01

    Full Text Available During their operation, wind turbine blades are eroded due to rain and hail, or they are contaminated with insects. Since the relative inflow velocity is higher at the outer than at the inner part of the blades, erosion occurs mostly at the outer blade region. In order to prevent strong erosion, it is possible to install a leading edge protection, which can be applied to the blades after the initial installation, but changes the shape of the initial airfoil sections. It is unclear how this modification influences the aerodynamic performance of the turbine. Hence, it is investigated in this work. The NREL 5 MW turbine is simulated with clean and eroded blades, which are compared to coated blades equipped with leading edge protection. Aerodynamic polars are generated by means of Computational Fluid Dynamics, and load calculations are conducted using the blade element momentum theory. The analysis in this work shows that, compared to clean rotor blades, the worse aerodynamic behaviour of strongly eroded blades can lead to power losses of 9 % . In contrast, coated blades only have a small impact on the turbine power of less than 1 % .

  4. 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.

  5. Failure analysis of turbine blades

    International Nuclear Information System (INIS)

    Iorio, A.F.; Crespi, J.C.

    1989-01-01

    Two 20 MW gas turbines suffered damage in blades belonging to the 2nd. stage of the turbine after 24,000 hours of duty. From research it arises that the fuel used is not quite adequate to guarantee the blade's operating life due to the excess of SO 3 , C and Na existing in combustion gases which cause pitting to the former. Later, the corrosion phenomenon is presented under tension produced by working stress enhanced by pitting where Pb is its main agent. A change of fuel is recommended thus considering the blades will reach the operational life they were designed for. (Author) [es

  6. Mapping the world: cartographic and geographic visualization by the United Nations Geospatial Information Section (formerly Cartographic Section)

    Science.gov (United States)

    Kagawa, Ayako; Le Sourd, Guillaume

    2018-05-01

    United Nations Secretariat activities, mapping began in 1946, and by 1951, the need for maps increased and an office with a team of cartographers was established. Since then, with the development of technologies including internet, remote sensing, unmanned aerial systems, relationship database management and information systems, geospatial information provides an ever-increasing variation of support to the work of the Organization for planning of operations, decision-making and monitoring of crises. However, the need for maps has remained intact. This presentation aims to highlight some of the cartographic representation styles over the decades by reviewing the evolution of selected maps by the office, and noting the changing cognitive and semiotic aspects of cartographic and geographic visualization required by the United Nations. Through presentation and analysis of these maps, the changing dynamics of the Organization in information management can be reflected, with a reminder of the continuing and expanding deconstructionist role of a cartographer, now geospatial information management experts.

  7. Design Procedure of 4-Bladed Propeller

    African Journals Online (AJOL)

    PROF. O. E. OSUAGWU

    2013-09-01

    Sep 1, 2013 ... West African Journal of Industrial and Academic Research Vol.8 No.1 September 2013 ..... Number of blades. 5. Taylor's wake friction (w). The speed of ship (Vs), the number of propeller revolution (n), the blade number (Z) and the blade area ratio.... .... moment of inertia of a blade, the approximate.

  8. Wind tunnel study of helical and straight-bladed vertical-axis wind turbine wakes

    Science.gov (United States)

    Bagheri, Maryam; Araya, Daniel

    2017-11-01

    It is hypothesized that blade curvature can serve as a passive means to control fluid entrainment and wake recovery in vertical-axis wind turbine (VAWT) arrays. We test this experimentally in a wind tunnel using two different VAWT configurations, one with straight blades and another with helical blades, keeping all other experimental parameters fixed. A small-scale, commercially available VAWT (15W max power) is used as the baseline wind tunnel model in each case. The commercial VAWT blades are replaced with either straight or helical blades that are 3D-printed extrusions of the same airfoil cross-section. Results from smoke flow visualization, three-component wake velocity measurements, and turbine power data are presented. These results give insight into the potential use of VAWTs with curved blades in utility-scale wind farms.

  9. Bladed disc crack diagnostics using blade passage signals

    Science.gov (United States)

    Hanachi, Houman; Liu, Jie; Banerjee, Avisekh; Koul, Ashok; Liang, Ming; Alavi, Elham

    2012-12-01

    One of the major potential faults in a turbo fan engine is the crack initiation and propagation in bladed discs under cyclic loads that could result in the breakdown of the engines if not detected at an early stage. Reliable fault detection techniques are therefore in demand to reduce maintenance cost and prevent catastrophic failures. Although a number of approaches have been reported in the literature, it remains very challenging to develop a reliable technique to accurately estimate the health condition of a rotating bladed disc. Correspondingly, this paper presents a novel technique for bladed disc crack detection through two sequential signal processing stages: (1) signal preprocessing that aims to eliminate the noises in the blade passage signals; (2) signal postprocessing that intends to identify the crack location. In the first stage, physics-based modeling and interpretation are established to help characterize the noises. The crack initiation can be determined based on the calculated health monitoring index derived from the sinusoidal effects. In the second stage, the crack is located through advanced detrended fluctuation analysis of the preprocessed data. The proposed technique is validated using a set of spin rig test data (i.e. tip clearance and time of arrival) that was acquired during a test conducted on a bladed military engine fan disc. The test results have demonstrated that the developed technique is an effective approach for identifying and locating the incipient crack that occurs at the root of a bladed disc.

  10. The Effect of Mounting Vortex Generators on the DTU 10MW Reference Wind Turbine Blade

    DEFF Research Database (Denmark)

    Skrzypinski, Witold Robert; Gaunaa, Mac; Bak, Christian

    2014-01-01

    The aim of the current work is to analyze possible advantages of mounting Vortex Generators (VG's) on a wind turbine blade. Specifically, the project aims at investigating at which radial sections of the DTU 10 MW Reference Wind Turbine blade it is most beneficial to mount the VG's in order...

  11. The effect of delaminations on local buckling in wind turbine blades

    DEFF Research Database (Denmark)

    Haselbach, Philipp Ulrich; Bitsche, Robert; Branner, Kim

    2015-01-01

    In this article the effect of delaminations on the load carrying capacity of a large wind turbine blade is studied numerically. For this purpose an 8.65 m long blade section with different initial delaminations in the main spar was subjected to a flapwise dominated bending moment. The model...

  12. New blades shape up for dozers

    Energy Technology Data Exchange (ETDEWEB)

    Chironis, N.P.

    1985-05-01

    This article discusses the design of blades used on dozers for the reclamation work following surface mining. Two blades are described which have led to a 50% reduction in reclamation costs and a 20% reduction in fuel requirements over conventional equipment. These results are from work carried out at the Kayenta mine in Arizona, USA. Design considerations in the development of the blades are described. Descriptions of both the centre flow blades and the universal blades are given.

  13. Characteristics of unit-level patient safety culture in hospitals in Japan: a cross-sectional study.

    Science.gov (United States)

    Fujita, Shigeru; Seto, Kanako; Kitazawa, Takefumi; Matsumoto, Kunichika; Hasegawa, Tomonori

    2014-10-22

    Patient safety culture (PSC) has an important role in determining safety and quality in healthcare. Currently, little is known about the status of unit-level PSC in hospitals in Japan. To develop appropriate strategies, characteristics of unit-level PSC should be investigated. Work units may be classified according to the characteristics of PSC, and common problems and appropriate strategies may be identified for each work unit category. This study aimed to clarify the characteristics of unit-level PSC in hospitals in Japan. In 2012, a cross-sectional study was conducted at 18 hospitals in Japan. The Hospital Survey on Patient Safety Culture questionnaire, developed by the United States Agency for Healthcare Research and Quality, was distributed to all healthcare workers (n =12,076). Percent positive scores for 12 PSC sub-dimensions were calculated for each unit, and cluster analysis was used to categorise the units according to the percent positive scores. A generalised linear mixed model (GLMM) was used to analyse the results of the cluster analysis, and odds ratios (ORs) for categorisation as high-PSC units were calculated for each unit type. A total of 9,124 respondents (75.6%) completed the questionnaire, and valid data from 8,700 respondents (72.0%) were analysed. There were 440 units in the 18 hospitals. According to the percent positive scores for the 12 sub-dimensions, the 440 units were classified into 2 clusters: high-PSC units (n =184) and low-PSC units (n =256). Percent positive scores for all PSC sub-dimensions for high-PSC units were significantly higher than those for low-PSC units. The GLMM revealed that the combined unit type of 'Obstetrics and gynaecology ward, perinatal ward or neonatal intensive care unit' was significantly more likely to be categorised as high-PSC units (OR =9.7), and 'Long-term care ward' (OR =0.2), 'Rehabilitation unit' (OR =0.2) and 'Administration unit' (OR =0.3) were significantly less likely to be categorised as high

  14. Application of Circulation Controlled Blades for Vertical Axis Wind Turbines

    Directory of Open Access Journals (Sweden)

    Velissarios Kourkoulis

    2013-07-01

    Full Text Available The blades of a vertical axis wind turbine (VAWT rotor see an inconsistent angle of attack through its rotation. Consequently, VAWT blades generally use symmetrical aerofoils with a lower lift-to-drag ratio than cambered aerofoils tailored to maximise horizontal axis wind turbine rotor performance. This paper considers the feasibility of circulation controlled (CC VAWT blades, using a tangential air jet to provide lift and therefore power augmentation. However CC blade sections require a higher trailing-edge thickness than conventional sections giving rise to additional base drag. The choice of design parameters is a compromise between lift augmentation, additional base drag as well as the power required to pump the air jet. Although CC technology has been investigated for many years, particularly for aerospace applications, few researchers have considered VAWT applications. This paper considers the feasibility of the technology, using Computational Fluid Dynamics to evaluate a baseline CC aerofoil with different trailing-edge ellipse shapes. Lift and drag increments due to CC are considered within a momentum based turbine model to determine net power production. The study found that for modest momentum coefficients significant net power augmentation can be achieved with a relatively simple aerofoil geometry if blowing is controlled through the blades rotation.

  15. Cross-sectional multicenter study of patients with urea cycle disorders in the United States.

    Science.gov (United States)

    Tuchman, Mendel; Lee, Brendan; Lichter-Konecki, Uta; Summar, Marshall L; Yudkoff, Marc; Cederbaum, Stephen D; Kerr, Douglas S; Diaz, George A; Seashore, Margaretta R; Lee, Hye-Seung; McCarter, Robert J; Krischer, Jeffrey P; Batshaw, Mark L

    2008-08-01

    Inherited urea cycle disorders comprise eight disorders (UCD), each caused by a deficiency of one of the proteins that is essential for ureagenesis. We report on a cross-sectional investigation to determine clinical and laboratory characteristics of patients with UCD in the United States. The data used for the analysis was collected at the time of enrollment of individuals with inherited UCD into a longitudinal observation study. The study has been conducted by the Urea Cycle Disorders Consortium within the Rare Diseases Clinical Research Network (RDCRN) funded by the National Institutes of Health. One-hundred eighty-three patients were enrolled into the study. Ornithine transcarbamylase (OTC) deficiency was the most frequent disorder (55%), followed by argininosuccinic aciduria (16%) and citrullinemia (14%). Seventy-nine percent of the participants were white (16% Latinos), and 6% were African American. Intellectual and developmental disabilities were reported in 39% with learning disabilities (35%) and half had abnormal neurological examination. Sixty-three percent were on a protein restricted diet, 37% were on Na-phenylbutyrate and 5% were on Na-benzoate. Forty-five percent of OTC deficient patients were on L-citrulline, while most patients with citrullinemia (58%) and argininosuccinic aciduria (79%) were on L-arginine. Plasma levels of branched-chain amino acids were reduced in patients treated with ammonia scavenger drugs. Plasma glutamine levels were higher in proximal UCD and in neonatal type disease. The RDCRN allows comprehensive analyses of rare inherited UCD, their frequencies and current medical practices.

  16. 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

  17. Metallurgical failure analysis for a blade failed in a gas-turbine engine of a power plant

    International Nuclear Information System (INIS)

    Huda, Zainul

    2009-01-01

    The failed gas-turbine blades (first stage blades) (type Siemens V94.2 KWU) were acquired from TNB Research Sdn. Bhd: a subsidiary of Malaysian power-generation industry (TNB, Malaysia). The blades were sectioned for metallographic investigations. The microstructural characterization involved use of both optical as well as electron microscopes including application of EPMA technique. The Microstructures were compared for three spots selection i.e. leading edge of the blade (transverse and longitudinal), trailing edge of the blade (transverse and longitudinal), and centre (near the platform of the blade) (transverse and longitudinal). The material properties and behavior at high temperature were interpreted on the basis of the observed microstructures and the phases present in the alloy. The interpretations were related to the operating conditions of the turbine blade; and main cause of failure was found to be creep damage. Recommendations have been made for improved material performance.

  18. Termovision and electricity capacitance measurements as a evaluation of a helicopter rotor’s blades delamination

    Directory of Open Access Journals (Sweden)

    Gębura Andrzej

    2015-12-01

    Full Text Available The article presents essential elements reached during investigations of heat section of rotor blades which have been done in AFIT. The investigations were related to a valuation of helicopter’s rotor blades delamination. They used a method of thermal field measurement as well as a electricity capacitance between an airframe and a heat element of the installation. A suggestion of such measurements appeared during the disassembly of rotor blade heat sections when some local unglue of heat element’s tape from the structure of blade’s heating pack has seen. Spots nearby separation of adhesive are a potential area of a local temperature increase, both the electric heating element and the mechanical structure of the blade. This is especially dangerous for composite structures. Overheated composite structures characterized by reduced flexibility and becomes prone to cracking. Therefore, the possibility of non-invasive monitoring adhesive spots, without removing the blades would be particularly useful.

  19. Evaluation of blood reservation and use for caesarean sections in a tertiary maternity unit in south western Nigeria

    Directory of Open Access Journals (Sweden)

    Oshodi Yussuf A

    2010-09-01

    Full Text Available Abstract Background Haemorrhage from obstetric causes is the most common cause of maternal mortality in the developing world. Prevention of mortality from haemorrhage will necessarily involve prompt blood transfusions among other life saving measures. There are however limited stocks of fresh or stored blood in many health care facilities in Sub Saharan Africa. Caesarean section has been identified as a common indication for blood transfusion in obstetrics practice and its performance is often delayed by non availability of blood in our centre. An evaluation of blood reservation and use at caesarean sections in a tertiary maternity unit in Lagos, south western Nigeria should therefore assist in formulating the most rational blood transfusion policies. Methods Case records of 327 patients who had elective and emergency caesarian sections at the Lagos State University Teaching Hospital between 1st October and 31st December 2007 were reviewed. Data pertaining to age, parity, booking status, type and indication for Caesarean section, pre- and post-operative packed cell volume, blood loss at surgery, units of blood reserved in the blood bank, unit(s of blood transfused and duration of hospital stay was extracted and the data analysed. Results There were 1056 deliveries out of which 327 (31% were by Caesarean section. During the study period, a total of 654 units of blood were reserved in the blood bank and subsequently made available in theatre. Out of this number, only 89 (13.6% were transfused to 41 patients. Amongst those transfused, twenty-six (54% were booked and 31 (75.6% had primary caesarian section. About 81% of those transfused had emergency caesarean section. The most common indication for surgery among those transfused were placenta praevia (9 patients with 21 units of blood and cephalo-pelvic disproportion (8 patients with 13 units. Conclusion Even though a large number of units of blood was reserved and made available in the theatre at

  20. Grading technologies for the manufacture of innovative cutting blades

    Science.gov (United States)

    Rostek, Tim; Homberg, Werner

    2018-05-01

    Cutting blades for harvesting applications are used in a variety of agricultural machines. These parts are in contact with highly abrasive lawn clippings and often wear out within hours which results in high expensive re-sharpening maintenance. This paper relates to manufacturing techniques enhancing the durability of cutting blades based on a structural analysis of the prevailing wear mechanisms containing chipping and abrasive wear. Each mechanism results in specific demands on the cutting edge's mechanical characteristics. The design of evaluation methods respectively is one issue of the paper. This is basis for approaches to improve the cutting edge performance on purpose. On option to improve abrasive wear resistance and, thus, service life is the application of locally graded steel materials as semi-finished products for self-sharpening cutting blades. These materials comprise a layered structure consisting of a hard, wear resistant layer and a relatively softer layer which is lesser wear resistant. As the cutting blade is subjected to wear conditions, the less wear resistant layer wears faster than the relatively more wear resistant harder layer revealing a durable cross section of the cutting edge and, thus, cutting performance. Anyways, chipping is another key issue on the cutting edge's lifetime. Here, the cutting edges cross section by means of geometry and grind respectively as well as its mechanical properties matter. FEM analysis reveal innovative options to optimize the cross section of the blade as well as thermomechanical strengthening add further strength to reduce chipping. This paper contains a comprehensive strategy to improve cutting blades with use of innovative manufacturing technologies which apply application-specific graded mechanical characteristics and, thus, significantly improved performance characteristics.

  1. Tiltrotor research aircraft composite blade repairs: Lessons learned

    Science.gov (United States)

    Espinosa, Paul S.; Groepler, David R.

    1991-01-01

    The XV-15, N703NA Tiltrotor Research Aircraft located at the NASA Ames Research Center, Moffett Field, California, currently uses a set of composite rotor blades of complex shape known as the advanced technology blades (ATBs). The main structural element of the blades is a D-spar constructed of unidirectional, angled fiberglass/graphite, with the aft fairing portion of the blades constructed of a fiberglass cross-ply skin bonded to a Nomex honeycomb core. The blade tip is a removable laminate shell that fits over the outboard section of the spar structure, which contains a cavity to retain balance weights. Two types of tip shells are used for research. One is highly twisted (more than a conventional helicopter blade) and has a hollow core constructed of a thin Nomex-honeycomb-and-fiberglass-skin sandwich; the other is untwisted with a solid Nomex honeycomb core and a fiberglass cross-ply skin. During initial flight testing of the blades, a number of problems in the composite structure were encountered. These problems included debonding between the fiberglass skin and the honeycomb core, failure of the honeycomb core, failures in fiberglass splices, cracks in fiberglass blocks, misalignment of mated composite parts, and failures of retention of metal fasteners. Substantial time was spent in identifying and repairing these problems. Discussed here are the types of problems encountered, the inspection procedures used to identify each problem, the repairs performed on the damaged or flawed areas, the level of criticality of the problems, and the monitoring of repaired areas. It is hoped that this discussion will help designers, analysts, and experimenters in the future as the use of composites becomes more prevalent.

  2. Tiltrotor Research Aircraft composite blade repairs - Lessons learned

    Science.gov (United States)

    Espinosa, Paul S.; Groepler, David R.

    1992-01-01

    The XV-15, N703NA Tiltrotor Research Aircraft located at the NASA Ames Research Center, Moffett Field, California, currently uses a set of composite rotor blades of complex shape known as the advanced technology blades (ATBs). The main structural element of the blades is a D-spar constructed of unidirectional, angled fiberglass/graphite, with the aft fairing portion of the blades constructed of a fiberglass cross-ply skin bonded to a Nomex honeycomb core. The blade tip is a removable laminate shell that fits over the outboard section of the spar structure, which contains a cavity to retain balance weights. Two types of tip shells are used for research. One is highly twisted (more than a conventional helicopter blade) and has a hollow core constructed of a thin Nomex-honeycomb-and-fiberglass-skin sandwich; the other is untwisted with a solid Nomex honeycomb core and a fiberglass cross-ply skin. During initial flight testing of the blades, a number of problems in the composite structure were encountered. These problems included debonding between the fiberglass skin and the honeycomb core, failure of the honeycomb core, failures in fiberglass splices, cracks in fiberglass blocks, misalignment of mated composite parts, and failures of retention of metal fasteners. Substantial time was spent in identifying and repairing these problems. Discussed here are the types of problems encountered, the inspection procedures used to identify each problem, the repairs performed on the damaged or flawed areas, the level of criticality of the problems, and the monitoring of repaired areas. It is hoped that this discussion will help designers, analysts, and experimenters in the future as the use of composites becomes more prevalent.

  3. Straight-bladed Darrieus wind turbines - A protagonist's view

    Science.gov (United States)

    Migliore, P. G.

    The technology development and market penetration of Darrieus and propeller-type wind turbines is addressed. Important characteristics of competing configurations are compared, and it is claimed that aerodynamic efficiency is not a distinguishing feature. Advantages of the Darrieus machine include omni-directionality and self-limitation, but propeller types require less rotor length per unit swept area. It is argued that the straight-bladed Darrieus is much simpler than the curved-bladed and should be capable of comparable aerodynamic efficiency. Some of the problems of structural design, as well as blade induced drag losses and support-arm counter torque, diminish rapidly as machine size is increased. Taper ratio has similar beneficial effects.

  4. A morphing trailing edge flap system for wind turbine blades

    DEFF Research Database (Denmark)

    Aagaard Madsen, Helge; Barlas, Athanasios; Løgstrup Andersen, Tom

    2015-01-01

    system has been further developed in corporation with the industrial partners Hydratech Industries (DK) and Rehau (DE). A new trailing edge flap design with spanwise voids (channels) and with a chord of 15cm suitable for a 1m chord blade section was developed. It was then manufactured by extrusion...

  5. Aerodynamic Analysis of Morphing Blades

    Science.gov (United States)

    Harris, Caleb; Macphee, David; Carlisle, Madeline

    2016-11-01

    Interest in morphing blades has grown with applications for wind turbines and other aerodynamic blades. This passive control method has advantages over active control methods such as lower manufacturing and upkeep costs. This study has investigated the lift and drag forces on individual blades with experimental and computational analysis. The goal has been to show that these blades delay stall and provide larger lift-to-drag ratios at various angles of attack. Rigid and flexible airfoils were cast from polyurethane and silicone respectively, then lift and drag forces were collected from a load cell during 2-D testing in a wind tunnel. Experimental data was used to validate computational models in OpenFOAM. A finite volume fluid-structure-interaction solver was used to model the flexible blade in fluid flow. Preliminary results indicate delay in stall and larger lift-to-drag ratios by maintaining more optimal angles of attack when flexing. Funding from NSF REU site Grant EEC 1358991 is greatly appreciated.

  6. Evaluation of the Effect of Spar Cap Fiber Angle of Bending-Torsion Coupled Blades on the Aero-Structural Performance of Wind Turbines

    DEFF Research Database (Denmark)

    Sener, Ozgun; Farsadi, Touraj; Gozc, M. Ozan

    2018-01-01

    with the fatigue load mitigation in the whole wind turbine system, tower clearances, peak stresses in the blades, and power generation of wind turbines. For this purpose, a full E-glass/epoxy reference blade has been designed, following the inverse design methodology for a 5-MW wind turbine. An E-glass/epoxy blade...... with IBTC, and besides the fiber orientation angle, sectional properties of hybrid blades must be adjusted accordingly using proper number of carbon/epoxy layers in the sections of the blade with IBTC, in order to simultaneously reduce generator power losses and the FEL....

  7. Methods of Enhancing the Operating Characteristics of Gas-Turbine Blades

    Science.gov (United States)

    Ospennikova, O. G.; Visik, E. M.; Gerasimov, V. V.; Kolyadov, E. V.

    2017-12-01

    This paper considers the main tendencies of development and ways of introduction of new technological solutions and alloys in the production of industrial gas-turbine unit (GTU) blades and presents a review of modern corrosion-resistant alloys, casting units for high-gradient directional solidification, and the techniques providing the preparation of a single-crystal structure in the blades of stationary turbine plants.

  8. The heat transfer analysis of the first stage blade

    International Nuclear Information System (INIS)

    Hong, Yong Ju; Choi, Bum Seog; Park, Byung Gyu; Yoon, Eui Soo

    2001-01-01

    To get higher efficiency of gas turbine, the designer should have more higher Turbine Inlet Temperature(TIT). Today, modern gas turbine having sophisticated cooling scheme has TIT above 1,700 .deg. C. In the Korea, many gas turbine having TIT above 1,300 .deg. C was imported and being operated, but the gas with high TIT above 1,300 .deg. C in the turbine will give damage to liner of combustor, and blade of turbine and etc. So frequently maintenance for parts enduring high temperature was performed. In this study, the heat transfer analysis of cooling air in the internal cooling channel (network analysis) and temperature analysis of the blade (Finite Element Analysis) in the first stage rotor was conducted for development of the optimal cooling passage design procedure. The results of network analysis and FEM analysis of blade show that the high temperature spot are occurred at the leading edge, trailing edge near tip, and platform. So to get more reliable performance of gas turbine, the more efficient cooling method should be applied at the leading edge and tip section and the thermal barrier coating on the blade surface has important role in cooling blade

  9. Noise aspects at aerodynamic blade optimisation projects

    International Nuclear Information System (INIS)

    Schepers, J.G.

    1997-06-01

    The Netherlands Energy Research Foundation (ECN) has often been involved in industrial projects, in which blade geometries are created automatic by means of numerical optimisation. Usually, these projects aim at the determination of the aerodynamic optimal wind turbine blade, i.e. the goal is to design a blade which is optimal with regard to energy yield. In other cases, blades have been designed which are optimal with regard to cost of generated energy. However, it is obvious that the wind turbine blade designs which result from these optimisations, are not necessarily optimal with regard to noise emission. In this paper an example is shown of an aerodynamic blade optimisation, using the ECN-program PVOPT. PVOPT calculates the optimal wind turbine blade geometry such that the maximum energy yield is obtained. Using the aerodynamic optimal blade design as a basis, the possibilities of noise reduction are investigated. 11 figs., 8 refs

  10. Accuracy of an efficient framework for structural analysis of wind turbine blades

    DEFF Research Database (Denmark)

    Blasques, José Pedro Albergaria Amaral; Bitsche, Robert D.; Fedorov, Vladimir

    2016-01-01

    -section analysis tool is able to capture the effects stemming from material anisotropy and inhomogeneity for sections of arbitrary geometry. The proposed framework is very efficient and therefore ideally suited for integration within wind turbine aeroelastic design and analysis tools. A number of benchmark......This paper presents a novel framework for the structural design and analysis of wind turbine blades and establishes its accuracy. The framework is based on a beam model composed of two parts—a 2D finite element-based cross-section analysis tool and a 3D beam finite element model. The cross...... examples are presented comparing the results from the proposed beam model to 3D shell and solid finite element models. The examples considered include a square prismatic beam, an entire wind turbine rotor blade and a detailed wind turbine blade cross section. Phenomena at both the blade length scale...

  11. Indiana Studies: Hoosier History, Government, and People. Unit III: From Sectional Division to Political Unity.

    Science.gov (United States)

    Barger, Harry D.; And Others

    Unit 3 of a six-unit series on Indiana state history designed to be taught in Indiana secondary schools tells the story of Indiana from 1829 to 1908. Chapter 1 discusses national issues in an Indiana context. The effects of social movements such as Abolition, the underground railroad, and the Fugitive Slave Law on Indiana politics are examined.…

  12. The Magnitude and Time Course of Muscle Cross-section Decrease in Intensive Care Unit Patients

    NARCIS (Netherlands)

    Haaf, D. Ten; Hemmen, B.; Meent, H. van de; Bovend'Eerdt, T.J.H.

    2017-01-01

    OBJECTIVE: Bedriddenness and immobilization of patients at an intensive care unit may result in muscle atrophy and devaluation in quality of life. The exact effect of immobilization on intensive care unit patients is not known. The aim of this study was to investigate the magnitude and time course

  13. Active Blade Pitch Control for Straight Bladed Darrieus Vertical Axis Wind Turbine of New Design

    DEFF Research Database (Denmark)

    Chougule, Prasad; Nielsen, Søren R.K.; Basu, Biswajit

    2013-01-01

    in a previous publication. Further, it is well know that the variation of the blade pitch angle during the rotation improves the power efficiency. A blade pitch variation is implemented by active blade pitch control, which operates as per wind speed and position of the blade with respect to the rotor. A double...

  14. Wind Turbine Blade with Angled Girders

    DEFF Research Database (Denmark)

    2011-01-01

    The present invention relates to a reinforced blade for a wind turbine, particularly to a blade having a new arrangement of two or more girders in the blade, wherein each of the girders is connected to the upper part and the lower part of the shell and forms an angle with another girder thereby...

  15. Structural damage identification in wind turbine blades using piezoelectric active sensing with ultrasonic validation

    Energy Technology Data Exchange (ETDEWEB)

    Claytor, Thomas N [Los Alamos National Laboratory; Ammerman, Curtt N [Los Alamos National Laboratory; Park, Gyu Hae [Los Alamos National Laboratory; Farinholt, Kevin M [Los Alamos National Laboratory; Farrar, Charles R [Los Alamos National Laboratory; Atterbury, Marie K [Los Alamos National Laboratory

    2010-01-01

    This paper gives a brief overview of a new project at LANL in structural damage identification for wind turbines. This project makes use of modeling capabilities and sensing technology to understand realistic blade loading on large turbine blades, with the goal of developing the technology needed to automatically detect early damage. Several structural health monitoring (SHM) techniques using piezoelectric active materials are being investigated for the development of wireless, low power sensors that interrogate sections of the wind turbine blade using Lamb wave propagation data, frequency response functions (FRFs), and time-series analysis methods. The modeling and sensor research will be compared with extensive experimental testing, including wind tunnel experiments, load and fatigue tests, and ultrasonic scans - on small- to mid-scale turbine blades. Furthermore, this study will investigate the effect of local damage on the global response of the blade by monitoring low-frequency response changes.

  16. 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.

  17. Development of advanced blade pitching kinematics for cycloturbines and cyclorotors

    Science.gov (United States)

    Adams, Zachary Howard

    to achieve optimum performance. A novel inverse method was developed implementing a new semi-empirical curvilinear flow blade aerodynamic coefficient model to predict optimum cycloturbine blade pitch waveforms from the ideal fluid deceleration. These improved blade pitch waveforms were evaluated on a 1.37m diameter by 1.37m span cycloturbine to definitively characterize their improvement over existing blade pitch motions and demonstrate the practicality of a variable blade pitch system. The Fluxline Optimal pitching kinematics outperformed sinusoidal and fixed pitching kinematics. The turbine achieved a mean gross aerodynamic power coefficient of 0.44 (95% confidence interval: [0.388,0.490]) and 0.52 (95% confidence interval: [0.426,0.614]) at tip speed ratios (TSRs) of 1.5 and 2.25 respectively which exceeds all other low TSR vertical axis wind turbines. Two-dimensional incompressible Reynolds-averaged Navier-Stokes computational fluid dynamic simulations were used to characterize higher order effects of the blade interaction with the fluid. These simulations suggest Fluxline Optimal pitch kinematics achieve high power coefficients by evenly extracting energy from the flow without blade stall or detached turbine wakes. Fluxline Theory was adapted to inform the design of high efficiency cyclorotors by incorporating the concept of rotor angle of attack as well as a power and drag loss model for blade support structure. A blade element version of this theory predicts rotor performance. For hovering, a simplified variation of the theory instructs that cyclorotors will achieve the greatest power loading at low disk loadings with high solidity blades pitched to maximum lift coefficient. Increasing lift coefficients in the upstream portion of the rotor disproportionately increases performance compared to magnifying lift in the downstream portion. This suggests airfoil sections that counter curvilinear flow effects could improve hovering efficiency. Additionally, the

  18. The effect of a heated skate blade on the ice surface

    Energy Technology Data Exchange (ETDEWEB)

    Hache, A. [Moncton Univ., NB (Canada). Dept. of Physics and Astronomy

    2007-05-15

    A new hockey skate using a heated blade, called the Therma Blade, cuts ice friction by half, thereby improving skating performance but has created questions about melting and damage of the ice surface. This paper discussed the effect of the heated skate blade on the ice surface. The paper discussed the thermal power produced by the Therma Blade skate, the ice melting capacity of the therma blade, and the ice temperature profile around the heated blade. It also examined the power dissipation by friction comparing the cold versus the heated blade. Units and definitions as well as conversion factors were also presented in appendix format. Constants and technical specifications were listed in an appendix. It was concluded that the maximum melting capacity of the therma blade is 0.7 grams of ice per skate per minute. This is the upper limit as set by the laws of physics, and this requires the skate to be completely static over ice at 0 degrees Celsius and all the power drawn by the battery to reach the ice friction force. 5 refs., 1 tab., 2 figs.

  19. Composite blade damaging under impact

    NARCIS (Netherlands)

    Menouillard, T.; Réthoré, J.; Bung, H.; Suffis, A.

    2006-01-01

    Composites materials are now being used in primary aircraft structures, and other domains because of numerous advantages. A part of a continuous in-flight operating costs, gas turbine engine manufacturers are always looking for ways to decrease engine weight. This is the case of compressor blades

  20. Piercing the water surface with a blade: Singularities of the contact line

    Energy Technology Data Exchange (ETDEWEB)

    Alimov, Mars M. [Kazan Federal University, Kazan 420008 (Russian Federation); Kornev, Konstantin G. [Department of Materials Science & Engineering, Clemson University, Clemson, South Carolina 29634 (United States)

    2016-01-15

    An external meniscus on a narrow blade with a slit-like cross section is studied using the hodograph formulation of the Laplace nonlinear equation of capillarity. On narrow blades, the menisci are mostly shaped by the wetting and capillary forces; gravity plays a secondary role. To describe a meniscus in this asymptotic case, the model of Alimov and Kornev [“Meniscus on a shaped fibre: Singularities and hodograph formulation,” Proc. R. Soc. A 470, 20140113 (2014)] has been employed. It is shown that at the sharp edges of the blade, the contact line makes a jump. In the wetting case, the contact line sitting at each side of the blade is lifted above the points where the meniscus first meets the blade edges. In the non-wetting case, the contact line is lowered below these points. The contours of the constant height emanating from the blade edges generate unusual singularities with infinite curvatures at some points at the blade edges. The meniscus forms a unique surface made of two mirror-symmetric sheets fused together. Each sheet is supported by the contact line sitting at each side of the blade.

  1. Piercing the water surface with a blade: Singularities of the contact line

    International Nuclear Information System (INIS)

    Alimov, Mars M.; Kornev, Konstantin G.

    2016-01-01

    An external meniscus on a narrow blade with a slit-like cross section is studied using the hodograph formulation of the Laplace nonlinear equation of capillarity. On narrow blades, the menisci are mostly shaped by the wetting and capillary forces; gravity plays a secondary role. To describe a meniscus in this asymptotic case, the model of Alimov and Kornev [“Meniscus on a shaped fibre: Singularities and hodograph formulation,” Proc. R. Soc. A 470, 20140113 (2014)] has been employed. It is shown that at the sharp edges of the blade, the contact line makes a jump. In the wetting case, the contact line sitting at each side of the blade is lifted above the points where the meniscus first meets the blade edges. In the non-wetting case, the contact line is lowered below these points. The contours of the constant height emanating from the blade edges generate unusual singularities with infinite curvatures at some points at the blade edges. The meniscus forms a unique surface made of two mirror-symmetric sheets fused together. Each sheet is supported by the contact line sitting at each side of the blade

  2. Composite ceramic blade for a gas turbine

    Energy Technology Data Exchange (ETDEWEB)

    Rossmann, A; Hoffmueller, W; Krueger, W

    1980-06-26

    The gas turbine blade consists of a supporting metal core which has at its lower end a modelled root and a profile blade made of ceramics enclosing it at some distance. The invention deals with a reliable connection between these two parts of the rotor blade: from the top end of the blade core a head protrudes supporting the thin-walled profile blade from below with a projection each pointing into the interior. The design of the projections and supporting surfaces is described and illustrated by drawings.

  3. WindPACT Turbine Design Scaling Studies Technical Area 1-Composite Blades for 80- to 120-Meter Rotor

    Energy Technology Data Exchange (ETDEWEB)

    Griffin, D.A.

    2001-04-30

    The United States Department of Energy (DOE) through the National Renewable Energy Laboratory (NREL) implemented the Wind Partnership for Advanced Component Technologies (WindPACT) program. As part of the WindPACT program, Global Energy Concepts, LLC (GEC), was awarded contract number YAM-0-30203-01 to examine Technical Area 1-Blade Scaling, Technical Area 2-Turbine Rotor and Blade Logistics, and Technical Area 3-Self-Erecting Towers. This report documents the results of GEC's Technical Area 1-Blade Scaling. The primary objectives of the Blade-Scaling Study are to assess the scaling of current materials and manufacturing technologies for blades of 40 to 60 meters in length, and to develop scaling curves of estimated cost and mass for rotor blades in that size range.

  4. Anisotropic beam model for analysis and design of passive controlled wind turbine blades

    DEFF Research Database (Denmark)

    Branner, Kim; Blasques, José Pedro Albergaria Amaral; Kim, Taeseong

    . The developed fully coupled beam element and cross section analysis tool has been validated against both numerical calculations and experimental measurements. Numerical validation has been performed against beam type calculations including Variational Asymptotical Beam Section Analysis (VABS) and detailed shell...... and solid finite element analyses. Experimental validation included specially designed beams with built-in couplings, a full-scale blade section originally without couplings, which subsequently was modified with extra composite layers in order to obtain measurable couplings. Both static testing and dynamic...... modal analysis tests have been performed. The results from the project now make it possible to use structural couplings in an intelligent manner for the design of future wind turbine blades. The developed beam element is especially developed for wind turbine blades and can be used for modeling blades...

  5. Numerical simulation on vacuum solution heat treatment and gas quenching process of a low rhenium-containing Ni-based single crystal turbine blade

    Directory of Open Access Journals (Sweden)

    Zhe-xin Xu

    2016-11-01

    Full Text Available Numerical heat-transfer and turbulent flow model for an industrial high-pressure gas quenching vacuum furnace was established to simulate the heating, holding and gas fan quenching of a low rhenium-bearing Ni-based single crystal turbine blade. The mesh of simplified furnace model was built using finite volume method and the boundary conditions were set up according to the practical process. Simulation results show that the turbine blade geometry and the mutual shielding among blades have significant influence on the uniformity of the temperature distribution. The temperature distribution at sharp corner, thin wall and corner part is higher than that at thick wall part of blade during heating, and the isotherms show a toroidal line to the center of thick wall. The temperature of sheltered units is lower than that of the remaining part of blade. When there is no shelteration among multiple blades, the temperature distribution for all blades is almost identical. The fluid velocity field, temperature field and cooling curves of the single and multiple turbine blades during gas fan quenching were also simulated. Modeling results indicate that the loading tray, free outlet and the location of turbine blades have important influences on the flow field. The high-speed gas flows out from the nozzle is divided by loading tray, and the free outlet enhanced the two vortex flow at the end of the furnace door. The closer the blade is to the exhaust outlet and the nozzle, the greater the flow velocity is and the more adequate the flow is. The blade geometry has an effect on the cooling for single blade and multiple blades during gas fan quenching, and the effects in double layers differs from that in single layer. For single blade, the cooing rate at thin-walled part is lower than that at thick-walled part, the cooling rate at sharp corner is greater than that at tenon and blade platform, and the temperature at regions close to the internal position is

  6. Patient Safety Culture in Intensive Care Units from the Perspective of Nurses: A Cross-Sectional Study.

    Science.gov (United States)

    Farzi, Sedigheh; Moladoost, Azam; Bahrami, Masoud; Farzi, Saba; Etminani, Reza

    2017-01-01

    One of the goals of nursing is providing safe care, prevention of injury, and health promotion of patients. Patient safety in intensive care units is threatened for various reasons. This study aimed to survey patient safety culture from the perspective of nurses in intensive care units. This cross-sectional study was conducted in 2016. Sampling was done using the convenience method. The sample consisted of 367 nurses working in intensive care units of teaching hospitals affiliated to Isfahan University of Medical Sciences. Data collection was performed using a two-part questionnaire that included demographic and hospital survey on Patient Safety Culture (HSOPSC) questionnaire. Data analysis was done using descriptive statistics (mean and standard deviation). Among the 12 dimensions of safety culture, the nurses assigned the highest score to "team work within units" (97.3%) and "Organizational learning-continuous improvement" (84%). They assigned the least score to "handoffs and transitions"(21.1%), "non-punitive response to errors" (24.7%), "Staffing" (35.6%), "Communication openness" (47.5%), and "Teamwork across units" (49.4%). The patient safety culture dimensions have low levels that require adequate attention and essential measures of health care centers including facilitating teamwork, providing adequate staff, and developing a checklist of handoffs and transitions. Furthermore, to increase reporting error and to promote a patient safety culture in intensive care units, some strategies should be adopted including a system-based approach to deal with the error.

  7. Bed Utilisation in an Irish Regional Paediatric Unit A Cross-Sectional Study Using the Paediatric Appropriateness Evaluation Protocol (PAEP)

    LENUS (Irish Health Repository)

    Ó hAiseadha, Coilín

    2016-05-01

    Increasing demand for limited healthcare resources raises questions about appropriate use of inpatient beds. In the first paediatric bed utilisation study at a regional university centre in Ireland, we conducted a cross-sectional study to audit the utilisation of inpatient beds at the Regional Paediatric Unit (RPU) in University Hospital Limerick (UHL), Limerick, Ireland and also examined hospital activity data, to make recommendations for optimal use of inpatient resources.

  8. Effects of Blade Boundary Layer Transition and Daytime Atmospheric Turbulence on Wind Turbine Performance Analyzed with Blade-Resolved Simulation and Field Data

    Science.gov (United States)

    Nandi, Tarak Nath

    Relevant to utility scale wind turbine functioning and reliability, the present work focuses on enhancing our understanding of wind turbine responses from interactions between energy-dominant daytime atmospheric turbulence eddies and rotating blades of a GE 1.5 MW wind turbine using a unique data set from a GE field experiment and computer simulations at two levels of fidelity. Previous studies have shown that the stability state of the lower troposphere has a major impact on the coherent structure of the turbulence eddies, with corresponding differences in wind turbine loading response. In this study, time-resolved aerodynamic data measured locally at the leading edge and trailing edge of three outer blade sections on a GE 1.5 MW wind turbine blade and high-frequency SCADA generator power data from a daytime field campaign are combined with computer simulations that mimic the GE wind turbine within a numerically generated atmospheric boundary layer (ABL) flow field which is a close approximation of the atmospheric turbulence experienced by the wind turbine in the field campaign. By combining the experimental and numerical data sets, this study describes the time-response characteristics of the local loadings on the blade sections in response to nonsteady nonuniform energetic atmospheric turbulence eddies within a daytime ABL which have spatial scale commensurate with that of the turbine blade length. This study is the first of its kind where actuator line and blade boundary layer resolved CFD studies of a wind turbine field campaign are performed with the motivation to validate the numerical predictions with the experimental data set, and emphasis is given on understanding the influence of the laminar to turbulent transition process on the blade loadings. The experimental and actuator line method data sets identify three important response time scales quantified at the blade location: advective passage of energy-dominant eddies (≈25 - 50 s), blade rotation (1P

  9. Organisational and environmental characteristics of residential aged care units providing highly person-centred care: a cross sectional study.

    Science.gov (United States)

    Sjögren, Karin; Lindkvist, Marie; Sandman, Per-Olof; Zingmark, Karin; Edvardsson, David

    2017-01-01

    Few studies have empirically investigated factors that define residential aged care units that are perceived as being highly person-centred. The purpose of this study was to explore factors characterising residential aged care units perceived as being highly person-centred, with a focus on organisational and environmental variables, as well as residents' and staff' characteristics. A cross-sectional design was used. Residents ( n  = 1460) and staff ( n  = 1213) data from 151 residential care units were collected, as well as data relating to characteristics of the organisation and environment, and data measuring degree of person-centred care. Participating staff provided self-reported data and conducted proxy ratings on residents . Descriptive and comparative statistics, independent samples t-test, Chi 2 test, Eta Squared and Phi coefficient were used to analyse data. Highly person-centred residential aged care units were characterized by having a shared philosophy of care, a satisfactory leadership, interdisciplinary collaboration and social support from colleagues and leaders, a dementia-friendly physical environment, staff having time to spend with residents, and a smaller unit size. Residential aged care units with higher levels of person-centred care had a higher proportion of staff with continuing education in dementia care, and a higher proportion of staff receiving regular supervision, compared to units with lower levels of person-centred care. It is important to target organisational and environmental factors, such as a shared philosophy of care, staff use of time, the physical environment, interdisciplinary support, and support from leaders and colleagues, to improve person-centred care in residential care units. Managers and leaders seeking to facilitate person-centred care in daily practice need to consider their own role in supporting, encouraging, and supervising staff.

  10. 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.

  11. Intubation of prehospital patients with curved laryngoscope blade is more successful than with straight blade.

    Science.gov (United States)

    Alter, Scott M; Haim, Eithan D; Sullivan, Alex H; Clayton, Lisa M

    2018-02-17

    Direct laryngoscopy can be performed using curved or straight blades, and providers usually choose the blade they are most comfortable with. However, curved blades are anecdotally thought of as easier to use than straight blades. We seek to compare intubation success rates of paramedics using curved versus straight blades. Design: retrospective chart review. hospital-based suburban ALS service with 20,000 annual calls. prehospital patients with any direct laryngoscopy intubation attempt over almost 9years. First attempt and overall success rates were calculated for attempts with curved and straight blades. Differences between the groups were calculated. 2299 patients were intubated by direct laryngoscopy. 1865 had attempts with a curved blade, 367 had attempts with a straight blade, and 67 had attempts with both. Baseline characteristics were similar between groups. First attempt success was 86% with a curved blade and 73% with a straight blade: a difference of 13% (95% CI: 9-17). Overall success was 96% with a curved blade and 81% with a straight blade: a difference of 15% (95% CI: 12-18). There was an average of 1.11 intubation attempts per patient with a curved blade and 1.13 attempts per patient with a straight blade (2% difference, 95% CI: -3-7). Our study found a significant difference in intubation success rates between laryngoscope blade types. Curved blades had higher first attempt and overall success rates when compared to straight blades. Paramedics should consider selecting a curved blade as their tool of choice to potentially improve intubation success. Copyright © 2018 Elsevier Inc. All rights reserved.

  12. Cutting blade dentitions in squaliform sharks form by modification of inherited alternate tooth ordering patterns

    OpenAIRE

    Underwood, Charlie J.; Johanson, Z.; Smith, M.M.

    2016-01-01

    The squaliform sharks represent one of the most speciose shark clades. Many adult squaliforms have blade-like teeth, either on both jaws or restricted to the lower jaw, forming a continuous, serrated blade along the jaw margin. These teeth are replaced as a single unit and successor teeth lack the alternate arrangement present in other elasmobranchs. Micro-CT scans of embryos of squaliforms and a related outgroup (Pristiophoridae) revealed that the squaliform dentition pattern represents a hi...

  13. Aerodynamical calculation of turbomachinery bladings

    International Nuclear Information System (INIS)

    Fruehauf, H.H.

    1978-01-01

    Various flow models are presented in comparison to one another, these flow models being obtained from the basic equations of turbomachinery aerodynamics by means of a series of simplifying assumptions on the spatial distribution of the flow quantities. The simplifying assumptions are analysed precisely. With their knowledge it is possible to construct more accurate simplified flow models, which are necessary for the efficient aerodynamical development of highperformance turbomachinery bladings by means of numerical methods. (orig.) 891 HP [de

  14. Demonstration of partial pitch 2-bladed wind turbine

    DEFF Research Database (Denmark)

    Kim, Taeseong; Zahle, Frederik; Troldborg, Niels

    -sections on the blade as well as fully resolved rotor simulations, and finally simulations coupling HAWC2 with EllipSys3D, investigating the behaviors of the rotor at standstill, has been performed. For the WP3, the state-of-the art aeroelastic analysis tool, HAWC2, has been updated in order to consider the partial......This is the final report for the EUDP project performed from January 2012 to December 2015. The main objective for the project was to demonstrate the potential of the partial pitch two-bladed (PP-2B) technology. DTU Wind Energy took a responsibility for three workpackages (WPs) among 6 WPs which...... were aerodynamic evaluation of partial pitch technology (WP2), aeroelastic analysis of two-bladed turbine (WP3) and On-site testing (WP4). For the WP2, a comprehensive set of 3D CFD simulations including the gap between inner and outer part of the blade and vortex generators (VGs) of both cross...

  15. Multilayer polymer light-emitting diodes by blade coating method

    Science.gov (United States)

    Tseng, Shin-Rong; Meng, Hsin-Fei; Lee, Kuan-Chen; Horng, Sheng-Fu

    2008-10-01

    Multilayer polymer light-emitting diodes fabricated by blade coating are presented. Multilayer of polymers can be easily deposited by blade coating on a hot plate. The multilayer structure is confirmed by the total thickness and the cross section view in the scanning electron microscope. The film thickness variation is only 3.3% in 10cm scale and the film roughness is about 0.3nm in the micron scale. The efficiency of single layer poly(para-phenylene vinylene) copolymer Super Yellow and poly(9,9-dioctylfluorene) (PFO, deep blue) devices are 9 and 1.7cd/A, respectively, by blade coating. The efficiency of the PFO device is raised to 2.9cd/A with a 2-(4-tert-butylphenyl)-5-(4-biphenylyl)-1,3,4-oxadiazole (PBD) hole-blocking layer and to 2.3cd/A with a poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4'-(N-(4-sec-butylphenyl))diphenylamine)] elec-tron-blocking layer added by blade coating.

  16. Damage Identification of Wind Turbine Blades Using Piezoelectric Transducers

    Directory of Open Access Journals (Sweden)

    Seong-Won Choi

    2014-01-01

    Full Text Available This paper presents the experimental results of active-sensing structural health monitoring (SHM techniques, which utilize piezoelectric transducers as sensors and actuators, for determining the structural integrity of wind turbine blades. Specifically, Lamb wave propagations and frequency response functions at high frequency ranges are used to estimate the condition of wind turbine blades. For experiments, a 1 m section of a CX-100 blade is used. The goal of this study is to assess and compare the performance of each method in identifying incipient damage with a consideration given to field deployability. Overall, these methods yielded a sufficient damage detection capability to warrant further investigation. This paper also summarizes the SHM results of a full-scale fatigue test of a 9 m CX-100 blade using piezoelectric active sensors. This paper outlines considerations needed to design such SHM systems, experimental procedures and results, and additional issues that can be used as guidelines for future investigations.

  17. Surgical Procedures of the Elbow: A Nationwide Cross-Sectional Observational Study in the United States

    Directory of Open Access Journals (Sweden)

    Ahmet Kinaci

    2015-01-01

    Full Text Available Background:  Elbow surgery is shared by several subspecialties. We were curious about the most common elbow surgeries and their corresponding diagnoses in the United States.   Methods:  We used the National Hospital Discharge Survey (NHDS and the National Survey of Ambulatory Surgery (NSAS data gathered in 2006-databases that together provide an estimate of all inpatient and ambulatory surgical care in the US.  Results:  An estimated 150,000 elbow surgeries were performed in the US in 2006, 75% in an outpatient setting. The most frequent diagnosis treated operative was enthesopathy (e.g. lateral epicondylitis and it was treated with several different procedures. More than three quarters of all elbow surgeries treated enthesopathy, cubital tunnel syndrome, or fracture (radial head in particular. Arthroscopy and arthroplasty accounted for less than 10% of all elbow surgeries.  Conclusions:  Elbow surgery in the United States primarily addresses enthesopathies such as tennis elbow, cubital tunnel syndrome, and trauma. It is notable that some of the most common elbow surgeries (those that address enthesopathy and radial head fracture are some of the most variably utilized and debated.

  18. The use of wood for wind turbine blade construction

    Science.gov (United States)

    Gougeon, M.; Zuteck, M.

    1979-01-01

    The interrelationships between moisture and wood, conditions for dry rot spore activity, the protection of wood fibers from moisture, wood resin composites, wood laminating, quality control, and the mechanical properties of wood are discussed. The laminated veneer and the bonded sawn stock fabrication techniques, used in the construction of a turbine blade with a monocoque 'D' section forming the leading edge and a built up trailing edge section, are described. A 20 foot root end sample complete with 24 bonded-in studs was successfully subjected to large onetime loads in both the flatwise and edgewise directions, and to fatigue tests. Results indicate that wood is both a viable and advantageous material for use in wind turbine blades. The basic material is reasonably priced, domestically available, ecologically sound, and easily fabricated with low energy consumption.

  19. Towing Tank and Flume Testing of Passively Adaptive Composite Tidal Turbine Blades: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Murray, Robynne [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Ordonez-Sanchez, Stephanie [University of Strathclyde; Porter, Kate E. [University of Strathclyde; Johnstone, Cameron M. [University of Strathclyde; Doman, Darrel A. [Dalhousie University; Pegg, Michael J. [Dalhousie University

    2017-09-28

    Composite tidal turbine blades with bend-twist (BT) coupled layups allow the blade to self-adapt to local site conditions by passively twisting. Passive feathering has the potential to increase annual energy production and shed thrust loads and power under extreme tidal flows. Decreased hydrodynamic thrust and power during extreme conditions meann that the turbine support structure, generator, and other components can be sized more appropriately, resulting in a higher utilization factor and increased cost effectiveness. This paper presents new experimental data for a small-scale turbine with BT composite blades. The research team tested the turbine in the Kelvin Hydrodynamics Laboratory towing tank at the University of Strathclyde in Glasgow, United Kingdom, and in the recirculating current flume at the l Institut Francais de Recherche pour l Exploitation de la Mer Centre in Boulogne-sur-Mer, France. Tests were also performed on rigid aluminum blades with identical geometry, which yielded baseline test sets for comparison. The results from both facilities agreed closely, supporting the hypothesis that increased blade flexibility can induce load reductions. Under the most extreme conditions tested the turbine with BT blades had up to 11 percent lower peak thrust loads and a 15 percent reduction in peak power compared to the turbine with rigid blades. The load reductions varied as a function of turbine rotational velocity and ambient flow velocity.

  20. Effect of Wavy Trailing Edge on 100meter Flatback Wind Turbine Blade

    International Nuclear Information System (INIS)

    Yang, SJ; Baeder, J D

    2016-01-01

    The flatback trailing edge design for modern 100meter wind turbine blade has been developed and proposed to make wind turbine blade to be slender and lighter. On the other hand, it will increase aerodynamic drag; consequently the increased drag diminishes turbine power generation. Thus, an aerodynamic drag reducing technique should be accompanied with the flatback trailing edge in order to prevent loss of turbine power generation. In this work, a drag mitigation design, span-wise wavy trailing edge blade, has been applied to a modern 100meter blade. The span-wise trailing edge acts as a vortex generator, and breaks up the strong span-wise coherent trailing edge vortex structure at the flatback airfoil trailing edge which is a major source of large drag. Three-dimensional unsteady Computational Fluid Dynamics (CFD) simulations have been performed for real scale wind turbine blade geometries. Delayed Detached Eddy Simulation (DDES) with the modified laminar-turbulent transition model has been applied to obtain accurate flow field predictions. Graphical Processor Unit (GPU)-accelerated computation has been conducted to reduce computational costs of the real scale wind turbine blade simulations. To verify the structural reliability of the wavy modification of the blade a simple Eigen buckling analysis has been performed in the current study. (paper)

  1. CFD computations of wind turbine blade loads during standstill operation KNOW-BLADE, Task 3.1 report

    Energy Technology Data Exchange (ETDEWEB)

    Soerensen, N.N.; Johansen, J.; Conway, S.

    2004-06-01

    Two rotors blades are computed during standstill conditions, using two different Navier-Stokes solvers EDGE and EllipSys3D. Both steady and transient linear {kappa} - {omega} RANS turbulence models are applied, along with steady non-linear RANS and transient DES simulations. The STORK 5.0 WPX blade is computed a three different tip pitch angles, 0, 26 and 50 degrees tip pitch angle, while the NREL Phase-VI blade is computed at 90 degrees tip pitch angle. Generally the CFD codes reproduce the measured trends quite well and the two involved CFD codes give very similar results. The discrepancies observed can be explained by the difference in the applied turbulence models and the fact that the results from one of the solvers are presented as instantaneous values instead of averaged values. The comparison of steady and transient RANS results show that the gain of using time true computations are very limited for this case, with respect to mean quantities. The same can be said for the RANS/DES comparison performed for the NREL rotor, even though the DES computation shows improved agreement at the tip and root sections. Finally, it is shown that the DES methodology provides a much more physical representation of the heavily stalled part of the flow over blades at high angles of attack. (au)

  2. The angles of the fact rotor tipvanes on the rods and on the blades

    NARCIS (Netherlands)

    Bruining, A.

    1988-01-01

    This report contains the data of the angles of the tipvanes of the FACT rotor. These tipvanes were used on the FACT rotor blades and rods. Two sets uf tipvanes were measured: a set having a Liebeck air-foil section and a set with a NACA airfoil section. The tipvanes with the Liebeck airfoil section

  3. Peripheral mowing blade. Final report ending 08/24/00

    Energy Technology Data Exchange (ETDEWEB)

    Darden, John A.

    2000-08-24

    The first prototype built for the peripheral mower blade was the nineteen foot batwing mower. It features twelve-inch blades, three-sixteenth thick. The configuration of the mower is three individual rotor gangs housed in separate housing all mounted to a centrally located housing. Each outer gang is driven by power being diverted through the center rotor. The power is supplied to each wing through means of a disconnect mechanism which allows the outer gangs to stop in the event that particular housing is raised by hydraulic power. This unit has given us unlimited information in the drive and power applications needed to drive the peripheral blade gangs. The nineteen foot unit has not changed much from the beginning, but information received from its performance has been applied to the building of a preproduction unit that is now in progress. Another prototype unit we have work with is the seven foot mounted mower. This unit consisted of a standard ASAE category I three-point hitch. The hitch was made by using an "A" frame which formed the attaching points for the mower and two back straps that gives support to the hitch assembly. The deck allowed for one-inch blade clearance at the top and featured a slanted deck extension at both the front and rear. The extension were formed by means of two breaks that run parallel to the blade gang and angled down at one hundred thirty degrees at the front and one hundred fifteen degrees at the rear. A roller is mounted across the back of the deck. This roller offers support to the deck while on the ground and is adjustable for height of cut control. This unit was made with a small roller, and too lighter hitch. After only a few hours of test proved that both items would have to be beefed up. The rear roller was increased to a four-inch diameter. The hitch was changed to a two-sided solid metal hitch three-eighths of an inch thick on the next machines.

  4. 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

  5. Computational investigation of flow control by means of tubercles on Darrieus wind turbine blades

    Science.gov (United States)

    Sevinç, K.; Özdamar, G.; Şentürk, U.; Özdamar, A.

    2015-09-01

    This work presents the current status of the computational study of the boundary layer control of a vertical axis wind turbine blade by modifying the blade geometry for use in wind energy conversion. The control method is a passive method which comprises the implementation of the tubercle geometry of a humpback whale flipper onto the leading edge of the blades. The baseline design is an H-type, three-bladed Darrieus turbine with a NACA 0015 cross-section. Finite-volume based software ANSYS Fluent was used in the simulations. Using the optimum control parameters for a NACA 634-021 profile given by Johari et al. (2006), turbine blades were modified. Three dimensional, unsteady, turbulent simulations for the blade were conducted to look for a possible improvement on the performance. The flow structure on the blades was investigated and flow phenomena such as separation and stall were examined to understand their impact on the overall performance. For a tip speed ratio of 2.12, good agreement was obtained in the validation of the baseline model with a relative error in time- averaged power coefficient of 1.05%. Modified turbine simulations with a less expensive but less accurate turbulence model yielded a decrease in power coefficient. Results are shown comparatively.

  6. Hot spot detection system for vanes or blades of a combustion turbine

    Science.gov (United States)

    Twerdochlib, M.

    1999-02-02

    This invention includes a detection system that can determine if a turbine component, such as a turbine vane or blade, has exceeded a critical temperature, such as a melting point, along any point along the entire surface of the vane or blade. This system can be employed in a conventional combustion turbine having a compressor, a combustor and a turbine section. Included within this system is a chemical coating disposed along the entire interior surface of a vane or blade and a closed loop cooling system that circulates a coolant through the interior of the vane or blade. If the temperature of the vane or blade exceeds a critical temperature, the chemical coating will be expelled from the vane or blade into the coolant. Since while traversing the closed loop cooling system the coolant passes through a detector, the presence of the chemical coating in the coolant will be sensed by the system. If the chemical coating is detected, this indicates that the vane or blade has exceeded a critical temperature. 5 figs.

  7. Axial Fan Blade Vibration Assessment under Inlet Cross-Flow Conditions Using Laser Scanning Vibrometry

    Directory of Open Access Journals (Sweden)

    Till Heinemann

    2017-08-01

    Full Text Available In thermal power plants equipped with air-cooled condensers (ACCs, axial cooling fans operate under the influence of ambient flow fields. Under inlet cross-flow conditions, the resultant asymmetric flow field is known to introduce additional harmonic forces to the fan blades. This effect has previously only been studied numerically or by using blade-mounted strain gauges. For this study, laser scanning vibrometry (LSV was used to assess fan blade vibration under inlet cross-flow conditions in an adapted fan test rig inside a wind tunnel test section. Two co-rotating laser beams scanned a low-pressure axial fan, resulting in spectral, phase-resolved surface vibration patterns of the fan blades. Two distinct operating points with flow coefficients of 0.17 and 0.28 were examined, with and without inlet cross-flow influence. While almost identical fan vibration patterns were found for both reference operating points, the overall blade vibration increased by 100% at the low fan flow rate as a result of cross-flow, and by 20% at the high fan flow rate. While numerically predicted natural frequency modes could be confirmed from experimental data as minor peaks in the vibration amplitude spectrum, they were not excited significantly by cross-flow. Instead, primarily higher rotation-rate harmonics were amplified; that is, a synchronous blade-tip flapping was strongly excited at the blade-pass frequency.

  8. 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.

  9. Structural Testing of the Blade Reliability Collaborative Effect of Defect Wind Turbine Blades

    Energy Technology Data Exchange (ETDEWEB)

    Desmond, M. [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Hughes, S. [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Paquette, J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-06-08

    Two 8.3-meter (m) wind turbine blades intentionally constructed with manufacturing flaws were tested to failure at the National Wind Technology Center (NWTC) at the National Renewable Energy Laboratory (NREL) south of Boulder, Colorado. Two blades were tested; one blade was manufactured with a fiberglass spar cap and the second blade was manufactured with a carbon fiber spar cap. Test loading primarily consisted of flap fatigue loading of the blades, with one quasi-static ultimate load case applied to the carbon fiber spar cap blade. Results of the test program were intended to provide the full-scale test data needed for validation of model and coupon test results of the effect of defects in wind turbine blade composite materials. Testing was part of the Blade Reliability Collaborative (BRC) led by Sandia National Laboratories (SNL). The BRC seeks to develop a deeper understanding of the causes of unexpected blade failures (Paquette 2012), and to develop methods to enable blades to survive to their expected operational lifetime. Recent work in the BRC includes examining and characterizing flaws and defects known to exist in wind turbine blades from manufacturing processes (Riddle et al. 2011). Recent results from reliability databases show that wind turbine rotor blades continue to be a leading contributor to turbine downtime (Paquette 2012).

  10. Mobile Phone Use in Psychiatry Residents in the United States: Multisite Cross-Sectional Survey Study.

    Science.gov (United States)

    Gipson, Shih; Torous, John; Boland, Robert; Conrad, Erich

    2017-11-01

    Mobile technology ownership in the general US population and medical professionals is increasing, leading to increased use in clinical settings. However, data on use of mobile technology by psychiatry residents remain unclear. In this study, our aim was to provide data on how psychiatric residents use mobile phones in their clinical education as well as barriers relating to technology use. An anonymous, multisite survey was given to psychiatry residents in 2 regions in the United States, including New Orleans and Boston, to understand their technology use. All participants owned mobile phones, and 79% (54/68) used them to access patient information. The majority do not use mobile phones to implement pharmacotherapy (62%, 42/68) or psychotherapy plans (90%, 61/68). The top 3 barriers to using mobile technology in clinical care were privacy concerns (56%, 38/68), lack of clinical guidance (40%, 27/68), and lack of evidence (29%, 20/68). We conclude that developing a technology curriculum and engaging in research could address these barriers to using mobile phones in clinical practice. ©Shih Gipson, John Torous, Robert Boland, Erich Conrad. Originally published in JMIR Mhealth and Uhealth (http://mhealth.jmir.org), 01.11.2017.

  11. Evaluation of multisectional and two-section particulate matter photochemical grid models in the Western United States.

    Science.gov (United States)

    Morris, Ralph; Koo, Bonyoung; Yarwood, Greg

    2005-11-01

    Version 4.10s of the comprehensive air-quality model with extensions (CAMx) photochemical grid model has been developed, which includes two options for representing particulate matter (PM) size distribution: (1) a two-section representation that consists of fine (PM2.5) and coarse (PM2.5-10) modes that has no interactions between the sections and assumes all of the secondary PM is fine; and (2) a multisectional representation that divides the PM size distribution into N sections (e.g., N = 10) and simulates the mass transfer between sections because of coagulation, accumulation, evaporation, and other processes. The model was applied to Southern California using the two-section and multisection representation of PM size distribution, and we found that allowing secondary PM to grow into the coarse mode had a substantial effect on PM concentration estimates. CAMx was then applied to the Western United States for the 1996 annual period with a 36-km grid resolution using both the two-section and multisection PM representation. The Community Multiscale Air Quality (CMAQ) and Regional Modeling for Aerosol and Deposition (REMSAD) models were also applied to the 1996 annual period. Similar model performance was exhibited by the four models across the Interagency Monitoring of Protected Visual Environments (IMPROVE) and Clean Air Status and Trends Network monitoring networks. All four of the models exhibited fairly low annual bias for secondary PM sulfate and nitrate but with a winter overestimation and summer underestimation bias. The CAMx multisectional model estimated that coarse mode secondary sulfate and nitrate typically contribute nitrate when averaged across the more rural IMPROVE monitoring network.

  12. Fan Efficiency Improvement via Changing Guide Blade Shape Under Various Operating Conditions

    Directory of Open Access Journals (Sweden)

    G. I. Zamolodchikov

    2017-01-01

    Full Text Available The aim of this study is to examine the influence of sweep and tangential blade lean the guide vanes (GV on the pressure losses in the blade row, and development of an approach to creating the GV with a rationally-shaped blades to ensure increased efficiency in the partial operating conditions.A numerical simulation method was used for research. As an object to be studied, was used an axial fan comprising an impeller and a GV, which were profiled to have constant circulation of velocity in radius. Verification of numerical simulation was based on the experimental data of fan. It comprised a GV with a straight blade and a circular-arc blade, with an impeller remained stationary in both cases. Among the turbulence models under consideration, preference is given to k-ω, as under operating conditions close to design ones, its result falls within the confidence span of the experimental characteristics, and at much higher and lower discharge coefficients a discrepancy is 4% at most.  In addition to the characteristics, the fields of pressure losses in GV have been analyzed. Numerical modeling allowed us to have a well-reproduced structure of losses in the stationary blade row.Analysis of pressure loss fields has shown that in the original GV near the hub, on the blade back, under design conditions a flow breakdown takes off. In view of the research, was designed a new GV with a modified blade geometry. The GV blade axis near the hub was bent in the circumferential direction by 0.1 length of the blade. In the near-hub cross-sections the blade chord was increased by 10%.The results of numerical simulation have shown that, with the flow less than the designed one, a change of just the GV blade tip sections leads to reduced break-down zone near the hub by about 40% under both operating conditions without raising profile losses and to improved fan efficiency, which reduces fan drive power consumption under typical operating conditions in the propulsion

  13. Prospective cross-sectional study of tuberculosis screening in United Arab Emirates.

    Science.gov (United States)

    Almarzooqi, Farida; Alkhemeiri, Aysha; Aljaberi, Ahmed; Hashmey, Rayhan; Zoubeidi, Taoufik; Souid, Abdul-Kader

    2018-05-01

    Intense migrations from tuberculosis endemic areas to Gulf countries create special risks for people in the region. The purpose of this study was to provide data that could justify implementing universal, regular TB screening in UAE. This prospective, cross-sectional study used interferon-γ release assay (IGRA) to screen for TB among Emirati citizens between August-2016 and May-2017; expatriates were not included in this study. Participants were recruited from Emiratis attending Tawam Hospital Polyclinics for problems unrelated to TB risk assessment. IGRA was requested for all enrolled participants. A risk-assessment questionnaire was completed by all participants. In addition, a retrospective review of IGRA results (January-2011 to April-2016) was conducted to compare prevalence of positive IGRA in the 'prospective sample' with that in 'patients screened in the past'. Four hundred fifty-five participants (69% females) were enrolled in this study. Participants' age (mean±SD) was 42±16y. The majority of participants had traveled to or had helpers from TB-endemic areas. Two hundred forty (53%) participants had IGRA test. Forty-five (18.8%) participants had positive IGRA, similar to the retrospective results of 12.4% to 23.5%. The prevalence of positive-IGRA in this study is high. Copyright © 2018 The Author(s). Published by Elsevier Ltd.. All rights reserved.

  14. Work with visual display units and musculoskeletal disorders: A cross-sectional study

    Directory of Open Access Journals (Sweden)

    Matteo Riccò

    2016-12-01

    Full Text Available Background: Epidemiological studies have shown that employees working with visual display units (VDU are more likely to complain about musculoskeletal disorders (MSDs. The aim of this study has been to evaluate associations among MSDs and individuals and work-related factors. Material and Methods: A total of 1032 VDU workers were assessed about their personal (i.e., age, working history, smoking history, physical activity and work-related factors (i.e., predominant job tasks performed, work posture. Work environment was evaluated regarding fulfillment of the standard ISO 9241-5:1998. The investigation required a direct observation of participants (in order to accurately assess the prevalence of MSDs and workstations. Adjusted odds ratios (ORa were calculated by means of the logistic regression model. Results: Prevalence of MSDs was relatively high (53%. In general, MSDs were significantly associated with female sex (OR = 2.832, 95% confidence interval (CI: 2.178–3.683, age ≥ 50 years old (OR = 2.231, 95% CI: 1.236–4.026, longer exposure to VDU, both as working history (10–14 years: OR = 1.934, 95% CI: 1.301–2.875; ≥ 15 years: OR = 2.223, 95% CI: 1.510–3.271 and working time (30–39 h/week: OR = 1.537, 95% CI: 1.087–2.273. Inappropriate workstation design was confirmed by the multivariate analysis as a risk factor for MSDs (ORa = 2.375, 95% CI: 1.124–5.018. Conclusions: Musculoskeletal disorders were significantly associated with individual factors as well as characteristics of work environment. An appropriate design of workstations may significantly reduce their prevalence amongst VDU workers. Med Pr 2016;67(6:707–719

  15. Genetic particle swarm parallel algorithm analysis of optimization arrangement on mistuned blades

    Science.gov (United States)

    Zhao, Tianyu; Yuan, Huiqun; Yang, Wenjun; Sun, Huagang

    2017-12-01

    This article introduces a method of mistuned parameter identification which consists of static frequency testing of blades, dichotomy and finite element analysis. A lumped parameter model of an engine bladed-disc system is then set up. A bladed arrangement optimization method, namely the genetic particle swarm optimization algorithm, is presented. It consists of a discrete particle swarm optimization and a genetic algorithm. From this, the local and global search ability is introduced. CUDA-based co-evolution particle swarm optimization, using a graphics processing unit, is presented and its performance is analysed. The results show that using optimization results can reduce the amplitude and localization of the forced vibration response of a bladed-disc system, while optimization based on the CUDA framework can improve the computing speed. This method could provide support for engineering applications in terms of effectiveness and efficiency.

  16. Adaptor assembly for coupling turbine blades to rotor disks

    Science.gov (United States)

    Garcia-Crespo, Andres Jose; Delvaux, John McConnell

    2014-09-23

    An adaptor assembly for coupling a blade root of a turbine blade to a root slot of a rotor disk is described. The adaptor assembly includes a turbine blade having a blade root and an adaptor body having an adaptor root. The adaptor body defines a slot having an open end configured to receive the blade root of the turbine blade such that the adaptor root of the adaptor body and the blade root of the turbine blade are adjacent to one another when the blade root of the turbine blade is positioned within the slot. Both the adaptor root of the adaptor body and the blade root of the turbine blade are configured to be received within the root slot of the rotor disk.

  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. A cross-sectional study of emergency department boarding practices in the United States.

    Science.gov (United States)

    Pitts, Stephen R; Vaughns, Frances L; Gautreau, Marc A; Cogdell, Matthew W; Meisel, Zachary

    2014-05-01

    The median emergency department (ED) boarding time for admitted patients has been a nationally reportable core measure that now also affects ED accreditation and reimbursement. However, no direct national probability samples of ED boarding data have been available to guide this policy until now. The authors studied new National Hospital Ambulatory Medical Care Survey (NHAMCS) survey items to establish baseline values, to generate hypotheses for future research, and to help improve survey quality in the future. This was a cross-sectional, multistage, stratified annual analysis of EDs and ED visits from the National Hospital Ambulatory Medical Care Survey public use files from 2007 to 2010, a total of 139,502 visit records. These data represent the only national measure of ED boarding. The main outcome of interest was boarding duration for individual patient visits. Data analyses accounted for complex sampling design. The national median boarding time was 79 minutes, with an interquartile range of 36 to 145 minutes. The prevalence of boarding for more than 2 hours among admitted patients was 32% (95% confidence interval [CI] = 30% to 35%). Average ED volume, occupancy, acuity, and hospital admission rates increased abruptly from the second to the third quartile of median boarding duration. The half of hospitals with the longest median boarding times accounted for 73% of ED visits and 79% of ED hospitalizations nationally. Thirty-nine percent of EDs (95% CI = 32% to 46%) reported never holding patients for more than 2 hours, but visit-level analysis at these EDs found that 21% of admissions did in fact stay in the ED over 2 hours. Only 19% of EDs (95% CI = 16% to 22%) used a strategy of moving admitted patients to alternative sites in the hospital during crowded times. In this national survey, ED boarding of admitted patients disproportionately affects hospitals with higher ED volumes, which also see sicker patients who wait longer to be seen, but not hospitals with

  19. Anisotropic beam model for analysis and design of passive controlled wind turbine blades

    Energy Technology Data Exchange (ETDEWEB)

    Branner, K; Blasques, J P; Kim, T; Fedorov, V A; Berring, P; Bitsche, R D; Berggreen, C

    2012-02-15

    The main objective of the project was, through theoretical and experimental research, to develop and validate a fully coupled, general beam element that can be used for advanced and rapid analysis of wind turbine blades. This is fully achieved in the project and the beam element has even been implemented in the aeroelastic code HAWC2. It has also been demonstrated through a parametric study in the project that a promising possibility with the tool is to reduce fatigue loads through structural couplings. More work is needed before these possibilities are fully explored and blades with structural couplings can be put into production. A cross section analysis tool BECAS (BEam Cross section Analysis Software) has been developed and validated in the project. BECAS is able to predict all geometrical and material induced couplings. This tool has obtained great interest from both industry and academia. The developed fully coupled beam element and cross section analysis tool has been validated against both numerical calculations and experimental measurements. Numerical validation has been performed against beam type calculations including Variational Asymptotical Beam Section Analysis (VABS) and detailed shell and solid finite element analyses. Experimental validation included specially designed beams with built-in couplings, a full-scale blade section originally without couplings, which subsequently was modified with extra composite layers in order to obtain measurable couplings. Both static testing and dynamic modal analysis tests have been performed. The results from the project now make it possible to use structural couplings in an intelligent manner for the design of future wind turbine blades. The developed beam element is especially developed for wind turbine blades and can be used for modeling blades with initial curvature (pre-bending), initial twist and taper. Finally, it have been studied what size of structural couplings can be obtained in current and future

  20. Nurse managers' decision-making in daily unit operation in peri-operative settings: a cross-sectional descriptive study.

    Science.gov (United States)

    Siirala, Eriikka; Peltonen, Laura-Maria; Lundgrén-Laine, Heljä; Salanterä, Sanna; Junttila, Kristiina

    2016-09-01

    To describe the tactical and the operational decisions made by nurse managers when managing the daily unit operation in peri-operative settings. Management is challenging as situations change rapidly and decisions are constantly made. Understanding decision-making in this complex environment helps to develop decision support systems to support nurse managers' operative and tactical decision-making. Descriptive cross-sectional design. Data were collected from 20 nurse managers with the think-aloud method during the busiest working hours and analysed using thematic content analysis. Nurse managers made over 700 decisions; either ad hoc (n = 289), near future (n = 268) or long-term (n = 187) by nature. Decisions were often made simultaneously with many interruptions. Ad hoc decisions covered staff allocation, ensuring adequate staff, rescheduling surgical procedures, confirmation tangible resources and following-up the daily unit operation. Decisions in the near future were: planning of surgical procedures and tangible resources, and planning staff allocation. Long-term decisions were: human recourses, nursing development, supplies and equipment, and finances in the unit. Decision-making was vulnerable to interruptions, which sometimes complicated the managing tasks. The results can be used when planning decision support systems and when defining the nurse managers' tasks in peri-operative settings. © 2016 John Wiley & Sons Ltd.

  1. Numerical simulations of unsteady flows past two-bladed rotors in forward-flight conditions

    International Nuclear Information System (INIS)

    Xu, H.; Mamou, M.; Khalid, M.

    2004-01-01

    The current paper presents time-accurate numerical simulations of compressible flows past two-bladed rotor configurations using a Chimera moving grid approach. The simulations are performed for a variety of flow conditions and various blade aspect ratios. The rotor blades are rectangular, untapered and untwisted planforms. Their cross-sections are built using the NACA 0012 airfoil profile. The aerodynamic performance of the rotor is investigated using the Euler equations. The CFD-FASTRAN code was used for the computations. The pressure distributions are benchmarked against the experimental data from Caradonna and Tung and a number of previous Euler calculations by Agarwal and Deese and Chen et al. The comparisons indicate that the current simulations for the forward flight conditions can reproduce the pressure distributions on the blade surfaces and the prediction of shockwave locations with reasonably good accuracy. (author)

  2. Numerical simulations of unsteady flows past two-bladed rotors in forward-flight conditions

    Energy Technology Data Exchange (ETDEWEB)

    Xu, H.; Mamou, M.; Khalid, M. [National Research Council, Inst. for Aerospace Research, Ottawa, Ontario (Canada)]. E-mail: Hongyi.Xu@nrc.ca

    2004-07-01

    The current paper presents time-accurate numerical simulations of compressible flows past two-bladed rotor configurations using a Chimera moving grid approach. The simulations are performed for a variety of flow conditions and various blade aspect ratios. The rotor blades are rectangular, untapered and untwisted planforms. Their cross-sections are built using the NACA 0012 airfoil profile. The aerodynamic performance of the rotor is investigated using the Euler equations. The CFD-FASTRAN code was used for the computations. The pressure distributions are benchmarked against the experimental data from Caradonna and Tung and a number of previous Euler calculations by Agarwal and Deese and Chen et al. The comparisons indicate that the current simulations for the forward flight conditions can reproduce the pressure distributions on the blade surfaces and the prediction of shockwave locations with reasonably good accuracy. (author)

  3. Evaluation of fatigue damage for wind turbine blades using acoustic emission

    Energy Technology Data Exchange (ETDEWEB)

    Jee, Hyun Sup; Ju, No Hoe [Korea Institute of Materials Science, Changwon (Korea, Republic of); So, Cheal Ho [Dongshin University, Naju (Korea, Republic of); Lee, Jong Kyu [Dept. of Physics, Pukyung National University, Busan (Korea, Republic of)

    2015-06-15

    In this study, the flap fatigue test of a 48 m long wind turbine blade was performed for 1 million cycles to evaluate the characteristics of acoustic emission signals generated from fatigue damage of the wind blades. As the number of hits and total energy continued to increase during the first 0.6 million cycles, blade damage was constant. The rise-time result showed that the major aspects of damage were initiation and propagation of matrix cracks. In addition, the signal analysis of each channel showed that the most seriously damaged sections were the joint between the skin and spar, 20 m from the connection, and the spot of actual damage was observable by visual inspection. It turned out that the event source location was related to the change in each channel{sup s} total energy. It is expected that these findings will be useful for the optimal design of wind turbine blades.

  4. Structural and mechanism design of an active trailing-edge flap blade

    DEFF Research Database (Denmark)

    Lee, Jae Hwan; Natarajan, Balakumaran; Eun, Won Jong

    2013-01-01

    , as the blade is able to withstand increased centrifugal force. The cross-section of the active blade is designed first. A stress/strain recovery analysis is then conducted to verify its structural integrity. A one-dimensional beam analysis is also carried out to assist with the construction of the fan diagram...... of the rotor through modification of unsteady aerodynamic loads. Piezoelectric actuators installed inside the blade manipulate the motion of the trailing edge flap. The proposed blade rotates at higher speed and additional structures are included to support the actuators and the flap. This improves the design....... To select the actuator and design the flap actuation region, the flap hinge moment is estimated via a CFD analysis. To obtain the desired flap deflection of ±4°, three actuators are required. The design of the flap actuation region is validated using a test bed with a skin hinge. However, because the skin...

  5. Evaluation of urethane for feasibility of use in wind turbine blade design

    Science.gov (United States)

    Lieblein, S.; Ross, R. S.; Fertis, D. G.

    1979-01-01

    A preliminary evaluation was conducted of the use of cast urethane as a possible material for low-cost blades for wind turbines. Specimen test data are presented for ultimate tensile strength, elastic modulus, flexural strain, creep, and fatigue properties of a number of urethane formulations. Data are also included for a large-scale urethane blade section composed of cast symmetrical half-profiles tested as a cantilever beam. Based on these results, an analysis was conducted of a full-scale blade design of cast urethane that meets the design specifications of the rotor blades for the NASA/DOE experimental 100-kW MOD-0 wind turbine. Because of the low value of elastic modulus for urethane (around 457 000 psi), the design loads would have to be carried by metal reinforcement. Considerations for further evaluation are noted.

  6. Design and manufacture of radar absorbing wind turbine blades - final report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-02-15

    This report describes the results of a collaborative project between QinetiQ Ltd and NOI (Scotland) Ltd to design and manufacture radar absorbent wind turbine blades. The main objectives were to: use predictive modelling to understand the contribution made by the blade to radar cross section (RCS) of the complete turbine; confirm that the turbine RCS could feasibility be reduced to appropriate levels through the use of radar absorbent material (RAM); and to demonstrate that introduction of stealth technology within current composite sections would allow RAM variants of the blade materials to be manufactured with minimal impact on the structure. The RCS of a turbine was predicted at frequencies at which representative air traffic control (ATC), weather and marine navigation radar systems operate. The material compositions that exist on the blades produced by NOI were studied and methods by which RAM could be introduced to each region were identified. RCS predictions for a blade having RAM over its surface were then repeated. The study showed that it was possible to modify all material regions of the NOI blades to create RAM with little or no degradation in structural properties, thus reducing detection by non-Doppler radar and ATC radars. A full practical demonstration of a stealthy turbine is recommended to allow the benefits of RCS reduction through the use of RAM to be quantified by all stakeholders.

  7. Development of Self-Powered Wireless Structural Health Monitoring (SHM) for Wind Turbine Blades

    Science.gov (United States)

    Lim, Dong-Won

    Wind turbine blade failure can lead to unexpected power interruptions. Monitoring wind turbine blades is important to ensure seamless electricity delivery from power generation to consumers. Structural health monitoring (SHM) enables early recognition of structural problems so that the safety and reliability of operation can be enhanced. This dissertation focuses on the development of a wireless SHM system for wind turbine blades. The sensor is comprised of a piezoelectric energy harvester (EH) and a telemetry unit. The sensor node is mounted on the blade surface. As the blade rotates, the blade flexes, and the energy harvester captures the strain energy on the blade surface. Once sufficient electricity is captured, a pulse is sent from the sensing node to a gateway. Then, a central monitoring algorithm processes a series of pulses received from all three blades. This wireless SHM, which uses commercially available components, can be retrofitted to existing turbines. The harvested energy for sensing can be estimated in terms of two factors: the available strain energy and conversion efficiency. The available strain energy was evaluated using the FAST (Fatigue, Aerodynamics, Structures, and Turbulence) simulator. The conversion efficiency was studied analytically and experimentally. An experimental set-up was designed to mimic the expected strain frequency and amplitude for rotor blades. From a series of experiments, the efficiency of a piezoelectric EH at a typical rotor speed (0.2 Hz) was approximately 0.5%. The power requirement for sending one measurement (280 muJ) can be achieved in 10 minutes. Designing a detection algorithm is challenging due to this low sampling rate. A new sensing approach-the timing of pulses from the transmitter-was introduced. This pulse timing, which is tied to the charging time, is indicative of the structural health. The SHM system exploits the inherent triple redundancy of the three blades. The timing data of the three blades are

  8. Flutter of Darrieus wind turbine blades

    Science.gov (United States)

    Ham, N. D.

    1978-01-01

    The testing of Darrieus wind turbines has indicated that under certain conditions, serious vibrations of the blades can occur, involving flatwise bending, torsion, and chordwise bending. A theoretical method of predicting the aeroelastic stability of the coupled bending and torsional motion of such blades with a view to determining the cause of these vibrations, and a means of suppressing them was developed.

  9. Estimation of gas turbine blades cooling efficiency

    NARCIS (Netherlands)

    Moskalenko, A.B.; Kozhevnikov, A.

    2016-01-01

    This paper outlines the results of the evaluation of the most thermally stressed gas turbine elements, first stage power turbine blades, cooling efficiency. The calculations were implemented using a numerical simulation based on the Finite Element Method. The volume average temperature of the blade

  10. Numerical analysis of turbine blade tip treatments

    Science.gov (United States)

    Gopalaswamy, Nath S.; Whitaker, Kevin W.

    1992-01-01

    Three-dimensional solutions of the Navier-Stokes equations for a turbine blade with a turning angle of 180 degrees have been computed, including blade tip treatments involving cavities. The geometry approximates a preliminary design for the GGOT (Generic Gas Oxidizer Turbine). The data presented here will be compared with experimental data to be obtained from a linear cascade using original GGOT blades. Results have been computed for a blade with 1 percent clearance, based on chord, and three different cavity sizes. All tests were conducted at a Reynolds number of 4 x 10 exp 7. The grid contains 39,440 points with 10 spanwise planes in the tip clearance region of 5.008E-04 m. Streamline plots and velocity vectors together with velocity divergence plots reveal the general flow behavior in the clearance region. Blade tip temperature calculations suggest placement of a cavity close to the upstream side of the blade tip for reduction of overall blade tip temperature. The solutions do not account for the relative motion between the endwall and the turbine blade. The solutions obtained are generally consistent with previous work done in this area,

  11. Massachusetts Large Blade Test Facility Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Rahul Yarala; Rob Priore

    2011-09-02

    Project Objective: The Massachusetts Clean Energy Center (CEC) will design, construct, and ultimately have responsibility for the operation of the Large Wind Turbine Blade Test Facility, which is an advanced blade testing facility capable of testing wind turbine blades up to at least 90 meters in length on three test stands. Background: Wind turbine blade testing is required to meet international design standards, and is a critical factor in maintaining high levels of reliability and mitigating the technical and financial risk of deploying massproduced wind turbine models. Testing is also needed to identify specific blade design issues that may contribute to reduced wind turbine reliability and performance. Testing is also required to optimize aerodynamics, structural performance, encourage new technologies and materials development making wind even more competitive. The objective of this project is to accelerate the design and construction of a large wind blade testing facility capable of testing blades with minimum queue times at a reasonable cost. This testing facility will encourage and provide the opportunity for the U.S wind industry to conduct more rigorous testing of blades to improve wind turbine reliability.

  12. Composite hub/metal blade compressor rotor

    Science.gov (United States)

    Yao, S.

    1978-01-01

    A low cost compressor rotor was designed and fabricated for a small jet engine. The rotor hub and blade keepers were compression molded with graphite epoxy. Each pair of metallic blades was held in the hub by a keeper. All keepers were locked in the hub with circumferential windings. Feasibility of fabrication was demonstrated in this program.

  13. Metallurgy of gas turbine blades with integral shroud and its influence on blades performance

    International Nuclear Information System (INIS)

    Mazur, Z.; Marino, C.; Kubiak, J.

    1999-01-01

    The influence of the microstructure of the gas turbine blades with integral shroud on the blades performance is presented. The analysis of the solidification process of the gas turbine blades during conventionally casting process (equiaxed grains) with all elements which has influence on the mode of its solidification and variation of the microstructure is carried out. Also, the evaluation of the failure of the gas turbine blade is present. A detailed analysis of the blade tip shroud microstructure (presence of the equiaxed and columnar grains) and its influence on the failure initiation and propagation is carried out. Finally, conclusions and some necessary improvements of the blades casting process to prevent blades failures are presented. (Author) 2 refs

  14. Flow separation on wind turbines blades

    Science.gov (United States)

    Corten, G. P.

    2001-01-01

    In the year 2000, 15GW of wind power was installed throughout the world, producing 100PJ of energy annually. This contributes to the total electricity demand by only 0.2%. Both the installed power and the generated energy are increasing by 30% per year world-wide. If the airflow over wind turbine blades could be controlled fully, the generation efficiency and thus the energy production would increase by 9%. Power Control To avoid damage to wind turbines, they are cut out above 10 Beaufort (25 m/s) on the wind speed scale. A turbine could be designed in such a way that it converts as much power as possible in all wind speeds, but then it would have to be to heavy. The high costs of such a design would not be compensated by the extra production in high winds, since such winds are rare. Therefore turbines usually reach maximum power at a much lower wind speed: the rated wind speed, which occurs at about 6 Beaufort (12.5 m/s). Above this rated speed, the power intake is kept constant by a control mechanism. Two different mechanisms are commonly used. Active pitch control, where the blades pitch to vane if the turbine maximum is exceeded or, passive stall control, where the power control is an implicit property of the rotor. Stall Control The flow over airfoils is called "attached" when it flows over the surface from the leading edge to the trailing edge. However, when the angle of attack of the flow exceeds a certain critical angle, the flow does not reach the trailing edge, but leaves the surface at the separation line. Beyond this line the flow direction is reversed, i.e. it flows from the trailing edge backward to the separation line. A blade section extracts much less energy from the flow when it separates. This property is used for stall control. Stall controlled rotors always operate at a constant rotation speed. The angle of attack of the flow incident to the blades is determined by the blade speed and the wind speed. Since the latter is variable, it determines

  15. MEASUREMENT OF ENDOTRACHEAL TUBE CUFF PRESSURE IN MECHANICALLYVENTILATED PATIENTS ON ARRIVAL TO INTENSIVE CARE UNIT - A CROSS-SECTIONAL STUDY

    Directory of Open Access Journals (Sweden)

    Arun Kumar Ajjappa

    2017-04-01

    Full Text Available BACKGROUND The monitoring of Endotracheal Tube (ETT cuff pressure in intubated patients on arrival to intensive care unit is very essential. The cuff pressure must be within an optimal range of 20-30cm H2O ensuring ventilation with no complications related to cuff overinflation and underinflation. This can be measured with a cuff pressure manometer. The aim of the study is to measure the endotracheal tube cuff pressure in patients on arrival to intensive care unit and to identify prevalence of endotracheal cuff underinflation and overinflation. MATERIALS AND METHODS A cross-sectional study was done on mechanically-ventilated patients who were intubated in casualty (emergency department on arrival to intensive care unit in S.S. Institute of Medical Sciences and Research Centre, Davangere. About 50 critically-ill patients intubated with a high volume, low pressure endotracheal tube were included in the study. An analogue manometer was used to measure the endotracheal tube cuff pressure. It was compared with the recommended level. The settings of mechanical ventilation, endotracheal tube size and peak airway pressure were recorded. RESULTS It was found that the mean cuff pressure was 64.10 cm of H2O with a standard deviation of 32.049. Of the measured cuff pressures, only 2% had pressures within an optimal range (20-30cm of H2O. 88% had cuff pressures more than 30cm of H2O. The mean peak airway pressure found to be 20.50cm of H2O with a Standard Deviation (SD of 5.064. CONCLUSION This study is done to emphasise the importance of cuff pressure measurement in all mechanically-ventilated patients as cuff pressure is found to be high in most of the patients admitted to intensive care unit. Complications of overinflation and underinflation can only be prevented if the acceptable cuff pressures are achieved.

  16. Patient safety culture in intensive care units from the perspective of nurses: A cross-sectional study

    Directory of Open Access Journals (Sweden)

    Sedigheh Farzi

    2017-01-01

    Full Text Available Background: One of the goals of nursing is providing safe care, prevention of injury, and health promotion of patients. Patient safety in intensive care units is threatened for various reasons. This study aimed to survey patient safety culture from the perspective of nurses in intensive care units. Materials and Methods: This cross-sectional study was conducted in 2016. Sampling was done using the convenience method. The sample consisted of 367 nurses working in intensive care units of teaching hospitals affiliated to Isfahan University of Medical Sciences. Data collection was performed using a two-part questionnaire that included demographic and hospital survey on Patient Safety Culture (HSOPSC questionnaire. Data analysis was done using descriptive statistics (mean and standard deviation. Results: Among the 12 dimensions of safety culture, the nurses assigned the highest score to “team work within units” (97.3% and “Organizational learning-continuous improvement” (84%. They assigned the least score to “handoffs and transitions”(21.1%, “non-punitive response to errors” (24.7%, “Staffing” (35.6%, “Communication openness” (47.5%, and “Teamwork across units” (49.4%. Conclusions: The patient safety culture dimensions have low levels that require adequate attention and essential measures of health care centers including facilitating teamwork, providing adequate staff, and developing a checklist of handoffs and transitions. Furthermore, to increase reporting error and to promote a patient safety culture in intensive care units, some strategies should be adopted including a system-based approach to deal with the error.

  17. 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)

  18. Modal properties and stability of bend–twist coupled wind turbine blades

    Directory of Open Access Journals (Sweden)

    A. R. Stäblein

    2017-06-01

    Full Text Available Coupling between bending and twist has a significant influence on the aeroelastic response of wind turbine blades. The coupling can arise from the blade geometry (e.g. sweep, prebending, or deflection under load or from the anisotropic properties of the blade material. Bend–twist coupling can be utilized to reduce the fatigue loads of wind turbine blades. In this study the effects of material-based coupling on the aeroelastic modal properties and stability limits of the DTU 10 MW Reference Wind Turbine are investigated. The modal properties are determined by means of eigenvalue analysis around a steady-state equilibrium using the aero-servo-elastic tool HAWCStab2 which has been extended by a beam element that allows for fully coupled cross-sectional properties. Bend–twist coupling is introduced in the cross-sectional stiffness matrix by means of coupling coefficients that introduce twist for flapwise (flap–twist coupling or edgewise (edge–twist coupling bending. Edge–twist coupling can increase or decrease the damping of the edgewise mode relative to the reference blade, depending on the operational condition of the turbine. Edge–twist to feather coupling for edgewise deflection towards the leading edge reduces the inflow speed at which the blade becomes unstable. Flap–twist to feather coupling for flapwise deflections towards the suction side increase the frequency and reduce damping of the flapwise mode. Flap–twist to stall reduces frequency and increases damping. The reduction of blade root flapwise and tower bottom fore–aft moments due to variations in mean wind speed of a flap–twist to feather blade are confirmed by frequency response functions.

  19. Lightning transient analysis in wind turbine blades

    DEFF Research Database (Denmark)

    Candela Garolera, Anna; Holbøll, Joachim; Madsen, Søren Find

    2013-01-01

    The transient behavior of lightning surges in the lightning protection system of wind turbine blades has been investigated in this paper. The study is based on PSCAD models consisting of electric equivalent circuits with lumped and distributed parameters involving different lightning current...... waveforms. The aim of the PSCAD simulations is to study the voltages induced by the lightning current in the blade that may cause internal arcing. With this purpose, the phenomenon of current reflections in the lightning down conductor of the blade and the electromagnetic coupling between the down conductor...... and other internal conductive elements of the blade is studied. Finally, several methods to prevent internal arcing are discussed in order to improve the lightning protection of the blade....

  20. The SNL100-01 blade :

    Energy Technology Data Exchange (ETDEWEB)

    Griffith, Daniel

    2013-02-01

    A series of design studies to investigate the effect of carbon on blade weight and performance for large blades was performed using the Sandia 100-meter All-glass Baseline Blade design as a starting point. This document provides a description of the final carbon blade design, which is termed as SNL100-01. This report includes a summary of the design modifications applied to the baseline all-glass 100-meter design and a description of the NuMAD model files that are made publicly available. This document is intended primarily to be a companion document to the distribution of the NuMAD blade model files for SNL100-01.

  1. Advanced Blade Manufacturing Project - Final Report

    Energy Technology Data Exchange (ETDEWEB)

    POORE, ROBERT Z.

    1999-08-01

    The original scope of the project was to research improvements to the processes and materials used in the manufacture of wood-epoxy blades, conduct tests to qualify any new material or processes for use in blade design and subsequently build and test six blades using the improved processes and materials. In particular, ABM was interested in reducing blade cost and improving quality. In addition, ABM needed to find a replacement material for the mature Douglas fir used in the manufacturing process. The use of mature Douglas fir is commercially unacceptable because of its limited supply and environmental concerns associated with the use of mature timber. Unfortunately, the bankruptcy of FloWind in June 1997 and a dramatic reduction in AWT sales made it impossible for ABM to complete the full scope of work. However, sufficient research and testing were completed to identify several promising changes in the blade manufacturing process and develop a preliminary design incorporating these changes.

  2. Applied modal analysis of wind turbine blades

    DEFF Research Database (Denmark)

    Pedersen, H.B.; Kristensen, O.J.D.

    2003-01-01

    In this project modal analysis has been used to determine the natural frequencies, damping and the mode shapes for wind turbine blades. Different methods to measure the position and adjust the direction of the measuring points are discussed. Differentequipment for mounting the accelerometers...... is investigated by repeated measurement on the same wind turbine blade. Furthermore the flexibility of the test set-up is investigated, by use ofaccelerometers mounted on the flexible adapter plate during the measurement campaign. One experimental campaign investigated the results obtained from a loaded...... and unloaded wind turbine blade. During this campaign the modal analysis are performed on ablade mounted in a horizontal and a vertical position respectively. Finally the results obtained from modal analysis carried out on a wind turbine blade are compared with results obtained from the Stig Øyes blade_EV1...

  3. Knowledge-based system for detailed blade design of turbines

    Science.gov (United States)

    Goel, Sanjay; Lamson, Scott

    1994-03-01

    A design optimization methodology that couples optimization techniques to CFD analysis for design of airfoils is presented. This technique optimizes 2D airfoil sections of a blade by minimizing the deviation of the actual Mach number distribution on the blade surface from a smooth fit of the distribution. The airfoil is not reverse engineered by specification of a precise distribution of the desired Mach number plot, only general desired characteristics of the distribution are specified for the design. Since the Mach number distribution is very complex, and cannot be conveniently represented by a single polynomial, it is partitioned into segments, each of which is characterized by a different order polynomial. The sum of the deviation of all the segments is minimized during optimization. To make intelligent changes to the airfoil geometry, it needs to be associated with features observed in the Mach number distribution. Associating the geometry parameters with independent features of the distribution is a fairly complex task. Also, for different optimization techniques to work efficiently the airfoil geometry needs to be parameterized into independent parameters, with enough degrees of freedom for adequate geometry manipulation. A high-pressure, low reaction steam turbine blade section was optimized using this methodology. The Mach number distribution was partitioned into pressure and suction surfaces and the suction surface distribution was further subdivided into leading edge, mid section and trailing edge sections. Two different airfoil representation schemes were used for defining the design variables of the optimization problem. The optimization was performed by using a combination of heuristic search and numerical optimization. The optimization results for the two schemes are discussed in the paper. The results are also compared to a manual design improvement study conducted independently by an experienced airfoil designer. The turbine blade optimization

  4. Crack of a first stage blade in a steam turbine

    Directory of Open Access Journals (Sweden)

    M. Nurbanasari

    2014-10-01

    Full Text Available The failure of the first stage blade in a steam turbine of 55 MW was investigated. The blade was made of 17-4 PH stainless steel and has been used for 12 years before failure. The current work aims to find out the main cause of the first stage blade failure. The methods for investigation were metallurgical analysis, chemical composition test, and hardness measurement. The result showed that there was no evidence the blade failure was due to material. The damage found on the blade namely crack on the blade root. Two locations of the crack observed at the blade root, which was at the tang and the fillet, with different failure modes. In general, the damage of the blade was started by the corrosion occurred on the blade root. The crack at the blade root tang was due to corrosion fatigue and the crack occurred at the blade root fillet owing to stress corrosion cracking.

  5. A sectional-splinting technique for impressing multiple implant units by eliminating the use of an open tray

    Directory of Open Access Journals (Sweden)

    Suryakant C. Deogade

    2014-01-01

    Full Text Available Since the inception of root form implant dentistry by P-I Branemark in the early 1980′s, so many technical advances have been put forward by several authors. However, the open tray impression technique is still performed for impressing multiple implant fixtures as it was first described in the original Branemark procedure manual. The most critical aspect for a successful implant-supported restoration is the passive and an accurate fit of superstructures to avoid preload and loading stresses. Splinting impression technique in multiple implants has gained popularity. Auto-polymerizing acrylic resin is among the most routinely practiced splinting material for multiple implant units. However, unfortunately, it exhibits shrinkage, which makes an impression quite inaccurate. This case report presents the solution to minimize the shrinkage of resin by utilizing sectional-splinting technique as advocated in the previous implant literature.

  6. Defining the Field of Existence of Shrouded Blades in High-Speed Gas Turbines

    Science.gov (United States)

    Belousov, Anatoliy I.; Nazdrachev, Sergeiy V.

    2018-01-01

    This work provides a method for determining the region of existence of banded blades of gas turbines for aircraft engines based on the analytical evaluation of tensile stresses in specific characteristic sections of the blade. This region is determined by the set of values of the parameter, which forms the law of distribution of the cross-sectional area of the cross-sections along the height of the airfoil. When seven independent parameters (gas-dynamic, structural and strength) are changed, the choice of the best option is proposed at the early design stage. As an example, the influence of the dimension of a turbine on the domain of the existence of banded blades is shown.

  7. Influence of pitch, twist, and taper on a blade`s performance loss due to roughness

    Energy Technology Data Exchange (ETDEWEB)

    Tangler, J.L. [National Renewable Energy Laboratory, Golden, Colorado (United States)

    1997-08-01

    The purpose of this study was to determine the influence of blade geometric parameters such as pitch, twist, and taper on a blade`s sensitivity to leading edge roughness. The approach began with an evaluation of available test data of performance degradation due to roughness effects for several rotors. In addition to airfoil geometry, this evaluation suggested that a rotor`s sensitivity to roughness was also influenced by the blade geometric parameters. Parametric studies were conducted using the PROP computer code with wind-tunnel airfoil characteristics for smooth and rough surface conditions to quantify the performance loss due to roughness for tapered and twisted blades relative to a constant-chord, non-twisted blade at several blade pitch angles. The results indicate that a constant-chord, non-twisted blade pitched toward stall will have the greatest losses due to roughness. The use of twist, taper, and positive blade pitch angles all help reduce the angle-of-attack distribution along the blade for a given wind speed and the associated performance degradation due to roughness. (au)

  8. Influence of pitch, twist, and taper on a blade`s performance loss due to roughness

    Energy Technology Data Exchange (ETDEWEB)

    Tangler, J.L. [National Renewable Energy Lab., Golden, CO (United States)

    1996-12-31

    The purpose of this study was to determine the influence of blade geometric parameters such as pitch, twist, and taper on a blade`s sensitivity to leading edge roughness. The approach began with an evaluation of available test data of performance degradation due to roughness effects for several rotors. In addition to airfoil geometry, this evaluation suggested that a rotor`s sensitivity to roughness was also influenced by the blade geometric parameters. Parametric studies were conducted using the PROP computer code with wind-tunnel airfoil characteristics for smooth and rough surface conditions to quantify the performance loss due to roughness for tapered and twisted blades relative to a constant-chord, non-twisted blade at several blade pitch angles. The results indicate that a constant-chord, non-twisted blade pitched toward stall will have the greatest losses due to roughness. The use of twist, taper, and positive blade pitch angles all help reduce the angle-of-attack distribution along the blade for a given wind speed and the associated performance degradation due to roughness. 8 refs., 6 figs.

  9. Combining Unsteady Blade Pressure Measurements and a Free-Wake Vortex Model to Investigate the Cycle-to-Cycle Variations in Wind Turbine Aerodynamic Blade Loads in Yaw

    Directory of Open Access Journals (Sweden)

    Moutaz Elgammi

    2016-06-01

    Full Text Available Prediction of the unsteady aerodynamic flow phenomenon on wind turbines is challenging and still subject to considerable uncertainty. Under yawed rotor conditions, the wind turbine blades are subjected to unsteady flow conditions as a result of the blade advancing and retreating effect and the development of a skewed vortical wake created downstream of the rotor plane. Blade surface pressure measurements conducted on the NREL Phase VI rotor in yawed conditions have shown that dynamic stall causes the wind turbine blades to experience significant cycle-to-cycle variations in aerodynamic loading. These effects were observed even though the rotor was subjected to a fixed speed and a uniform and steady wind flow. This phenomenon is not normally predicted by existing dynamic stall models integrated in wind turbine design codes. This paper couples blade pressure measurements from the NREL Phase VI rotor to a free-wake vortex model to derive the angle of attack time series at the different blade sections over multiple rotor rotations and three different yaw angles. Through the adopted approach it was possible to investigate how the rotor self-induced aerodynamic load fluctuations influence the unsteady variations in the blade angles of attack and induced velocities. The hysteresis loops for the normal and tangential load coefficients plotted against the angle of attack were plotted over multiple rotor revolutions. Although cycle-to-cycle variations in the angles of attack at the different blade radial locations and azimuth positions are found to be relatively small, the corresponding variations in the normal and tangential load coefficients may be significant. Following a statistical analysis, it was concluded that the load coefficients follow a normal distribution at the majority of blade azimuth angles and radial locations. The results of this study provide further insight on how existing engineering models for dynamic stall may be improved through

  10. Ultimate strength of a large wind turbine blade

    Energy Technology Data Exchange (ETDEWEB)

    Moelholt Jensen, Find

    2008-05-15

    The present PhD project contains a study of the structural static strength of wind turbine blades loaded in flap-wise direction. A combination of experimental and numerical work has been used to address the most critical failure mechanisms and to get an understanding of the complex structural behaviour of wind turbine blades. Four failure mechanisms observed during the fullscale tests and the corresponding FE-analysis are presented. Elastic mechanisms associated with failure, such as buckling, localized bending and the Brazier effect, are studied. Six different types of structural reinforcements helping to prevent undesired structural elastic mechanisms are presented. The functionality of two of the suggested structural reinforcements was demonstrated in full-scale tests and the rest trough FE-studies. The blade design under investigation consisted of an aerodynamic airfoil and a load carrying box girder. In total, five full-scale tests have been performed involving one complete blade and two shortened box girders. The second box girder was submitted to three independent tests covering different structural reinforcement alternatives. The advantages and disadvantages of testing a shortened load carrying box girder vs. an entire blade are discussed. Changes in the boundary conditions, loads and additional reinforcements, which were introduced in the box girder tests in order to avoid undesired structural elastic mechanisms, are presented. New and advanced measuring equipment was used in the fullscale tests to detect the critical failure mechanisms and to get an understanding of the complex structural behaviour. Traditionally, displacement sensors and strain gauges in blade tests are arranged based on an assumption of a Bernoulli-Euler beam structural response. In the present study it is shown that when following this procedure important information about distortions of the cross sections is lost. In the tests presented here, one of the aims was to measure distortion

  11. The occurrence of adverse events potentially attributable to nursing care in medical units: cross sectional record review.

    Science.gov (United States)

    D'Amour, Danielle; Dubois, Carl-Ardy; Tchouaket, Eric; Clarke, Sean; Blais, Régis

    2014-06-01

    Ensuring the safety of hospitalized patients remains a major challenge for healthcare systems, and nursing services are at the center of hospital care. Yet our knowledge about safety of nursing care is quite limited. In fact, most earlier studies examined one, or at most two, indicators, thus presenting an incomplete picture of safety at an institutional or broader level. Furthermore, methodologies have differed from one study to another, making benchmarking difficult. The aim of this study was to describe the frequencies of six adverse events widely considered in the literature to be nursing-sensitive outcomes and to estimate the degree to which these events could be attributed to nursing care. Cross-sectional review of charts of 2699 patients hospitalized on 22 medical units in 11 hospitals in Quebec, Canada. The events included: pressure sores, falls, medication administration errors, pneumonias, urinary infections, and inappropriate use of restraints. Experienced nurse reviewers abstracted patients' charts based on a grid developed for the study. Patient-level risk for at least one of these six adverse events was 15.3%, ranging from 9% to 28% across units. Of the 412 patients who experienced an event, 30% experienced two or more, for a total of 568 events. The risk of experiencing an adverse event with consequences was 6.2%, with a unit-level range from 3.2% to 13.5%. Abstractors concluded that 76.8% of the events were attributable to nursing care. While the measurement approach adopted here has limitations stemming from reliance on review of documentation, it provided a practical means of assessing several nursing-sensitive adverse events simultaneously. Given that patient safety issues are so complex, tracking their prevalence and impact is important, as is finding means of evaluating progress in reducing them. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

  12. Laser cladding of turbine blades

    International Nuclear Information System (INIS)

    Shepeleva, L.; Medres, B.; Kaplan, W.D.; Bamberger, M.

    2000-01-01

    A comparative study of two different techniques for the application of wear-resistant coatings for contact surfaces of shroud shelves of gas turbine engine blades (GTE) has been conducted. Wear-resistant coatings were applied on In713 by laser cladding with direct injection of the cladding powder into the melt pool. Laser cladding was conducted with a TRUMPF-2500, CW-CO 2 laser. The laser cladding was compared with commercially available plasma cladding with wire. Both plasma and laser cladded zones were characterized by optical and scanning electron microscopy. It was found that the laser cladded zone has a higher microhardness value (650-820 HV) compared with that of the plasma treated material (420-440 HV). This is a result of the significant reduction in grain size in the case of laser cladding. Unlike the plasma cladded zones, the laser treated material is free of micropores and microcracks. (orig.)

  13. The SNL100-02 blade :

    Energy Technology Data Exchange (ETDEWEB)

    Griffith, Daniel

    2013-11-01

    A series of design studies are performed to investigate the effects of advanced core materials and a new core material strategy on blade weight and performance for large blades using the Sandia 100-meter blade designs as a starting point. The initial core material design studies were based on the SNL100-01 100- meter carbon spar design. Advanced core material with improved performance to weight was investigated with the goal to reduce core material content in the design and reduce blade weight. A secondary element of the core study was to evaluate the suitability of core materials from natural, regrowable sources such as balsa and recyclable foam materials. The new core strategy for the SNL100-02 design resulted in a design mass of 59 tons, which is a 20% reduction from the most recent SNL100-01 carbon spar design and over 48% reduction from the initial SNL100-00 all-glass baseline blade. This document provides a description of the final SNL100-02 design, includes a description of the major design modifications, and summarizes the pertinent blade design information. This document is also intended to be a companion document to the distribution of the NuMAD blade model files for SNL100-02 that are made publicly available.

  14. Optimization of Heat Transfer on Thermal Barrier Coated Gas Turbine Blade

    Science.gov (United States)

    Aabid, Abdul; Khan, S. A.

    2018-05-01

    In the field of Aerospace Propulsion technology, material required to resist the maximum temperature. In this paper, using thermal barrier coatings (TBCs) method in gas turbine blade is used to protect hot section component from high-temperature effect to extend the service life and reduce the maintenance costs. The TBCs which include three layers of coating corresponding initial coat is super alloy-INCONEL 718 with 1 mm thickness, bond coat is Nano-structured ceramic-metallic composite-NiCoCrAIY with 0.15 mm thickness and top coat is ceramic composite-La2Ce2O7 with 0.09 mm thickness on the nickel alloy turbine blade which in turn increases the strength, efficiency and life span of the blades. Modeling a gas turbine blade using CATIA software and determining the amount of heat transfer on thermal barrier coated blade using ANSYS software has been performed. Thermal stresses and effects of different TBCs blade base alloys are considered using CATIA and ANSYS.

  15. Shape optimization of turbine blades with the integration of aerodynamics and heat transfer

    Directory of Open Access Journals (Sweden)

    Rajadas J. N.

    1998-01-01

    Full Text Available A multidisciplinary optimization procedure, with the integration of aerodynamic and heat transfer criteria, has been developed for the design of gas turbine blades. Two different optimization formulations have been used. In the first formulation, the maximum temperature in the blade section is chosen as the objective function to be minimized. An upper bound constraint is imposed on the blade average temperature and a lower bound constraint is imposed on the blade tangential force coefficient. In the second formulation, the blade average and maximum temperatures are chosen as objective functions. In both formulations, bounds are imposed on the velocity gradients at several points along the surface of the airfoil to eliminate leading edge velocity spikes which deteriorate aerodynamic performance. Shape optimization is performed using the blade external and coolant path geometric parameters as design variables. Aerodynamic analysis is performed using a panel code. Heat transfer analysis is performed using the finite element method. A gradient based procedure in conjunction with an approximate analysis technique is used for optimization. The results obtained using both optimization techniques are compared with a reference geometry. Both techniques yield significant improvements with the multiobjective formulation resulting in slightly superior design.

  16. Study of design and technology factors influencing gas turbine blade cooling

    Science.gov (United States)

    Shevchenko, I. V.; Garanin, I. V.; Rogalev, A. N.; Kindra, V. O.; Khudyakova, V. P.

    2017-11-01

    The knowledge of aerodynamic and thermal parameters of turbulators used in order to design an efficient blade cooling system. However, all experimental tests of the hydraulic and thermal characteristics of the turbulators were conducted on the rectangular shape channels with a strongly defined air flow direction. The actual blades have geometry of the channels that essentially differs from the rectangular shape. Specifically, the air flow in the back cavity of a blade with one and half-pass cooling channel changes its direction throughout the feather height. In most cases the ribs and pins are made with a tilt to the channel walls, which is determined by the moving element design of a mould for the ceramic rod element fabrication. All of the factors described above may result in the blade thermohydraulic model being developed failing to fully simulate the air flow and the heat exchange processes in some sections of the cooling path. Hence, the design temperature field will differ from the temperature field of an actual blade. This article studied the numerical data of design and technology factors influencing heat transfer in the cooling channels. The results obtained showed their substantial impact on the blade cooling efficiency.

  17. 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.

  18. Dependence of the mean time to failure of a hydraulic balancing machine unit on different factors for sectional pumps of the Alrosa JSC

    Science.gov (United States)

    Ovchinnikov, N. P.; Portnyagina, V. V.; Sobakina, M. P.

    2017-12-01

    This paper presents factors that have a greater impact on the mean time to failure of a hydraulic balancing machine unit working in underground kimberlite mines of the Alrosa JSC, the hydraulic balancing machine unit being the least reliable structural elements in terms of error-free operation. In addition, a multifactor linear dependence of mean time to failure of a hydraulic balancing machine unit is shown regarding it being parts of stage sectional pumps in the underground kimberlite mines of the Alrosa JSC. In prospect, this diagram can allow us to predict the durability of the least reliable structural element of a sectional pump.

  19. Structural Analysis of Basalt Fiber Reinforced Plastic Wind Turbine Blade

    Directory of Open Access Journals (Sweden)

    Mengal Ali Nawaz

    2014-07-01

    Full Text Available In this study, Basalt fiber reinforced plastic (BFRP wind turbine blade was analyzed and compared with Glass fiber reinforced plastic blade (GFRP. Finite element analysis (FEA of blade was carried out using ANSYS. Data for FEA was obtained by using rule of mixture. The shell element in ANSYS was used to simulate the wind turbine blade and to conduct its strength analysis. The structural analysis and comparison of blade deformations proved that BFRP wind turbine blade has better strength compared to GFRP wind turbine blade.

  20. Pin and roller attachment system for ceramic blades

    Science.gov (United States)

    Shaffer, J.E.

    1995-07-25

    In a turbine, a plurality of blades are attached to a turbine wheel by way of a plurality of joints which form a rolling contact between the blades and the turbine wheel. Each joint includes a pin and a pair of rollers to provide rolling contact between the pin and an adjacent pair of blades. Because of this rolling contact, high stress scuffing between the blades and the turbine wheel reduced, thereby inhibiting catastrophic failure of the blade joints. 3 figs.

  1. Multidisciplinary design optimization of film-cooled gas turbine blades

    OpenAIRE

    Shashishekara S. Talya; J. N. Rajadas; A. Chattopadhyay

    1999-01-01

    Design optimization of a gas turbine blade geometry for effective film cooling toreduce the blade temperature has been done using a multiobjective optimization formulation. Three optimization formulations have been used. In the first, the average blade temperature is chosen as the objective function to be minimized. An upper bound constraint has been imposed on the maximum blade temperature. In the second, the maximum blade temperature is chosen as the objective function to be minimized with ...

  2. Development of Standard Approach for Sickle Blade Manufacturing

    OpenAIRE

    Noordin, M. N. A; Hudzari, R. M; Azuan, H. N; Zainon, M. S; Mohamed, S. B; Wafi, S. A

    2016-01-01

    The sickle blade used in the motorised palm cutter known as “CANTAS” provides fast, easy and safe pruning and harvesting for those hard to reach applications. Jariz Technologies Company is experiencing problem in the consistency of sickle blade which was supplied by various blade manufacturers. Identifying the proper blade material with a certain hardness value would produce a consistent as well as long lasting sickle blade. A Standard Operating Procedure (SOP) in the manufacturing of the sic...

  3. Frailty in community-dwelling older people in Abu Dhabi, United Arab Emirates: a cross-sectional study

    Directory of Open Access Journals (Sweden)

    Saleha Jaber Al-Kuwaiti

    2015-11-01

    Full Text Available BackgroundFrailty describes the ageing-associated loss of physiological and psychological reserves leading to an increased risk of adverse health outcomes. Many developed countries view frailty as a major priority for their health and social care systems. Less is known about frailty in less-developed countries. The purpose of this study was to determine the prevalence of frailty in a sample of community dwelling older people in the United Arab Emirates.MethodsThis was a cross sectional study of community dwelling Emirati adults aged 55 years and older (n=160 in Abu Dhabi, United Arab Emirates. Data was collected at interview by questionnaire and physical measurements. Frailty was defined according to the criteria of the Fried Frailty Index. The prevalence of frailty and its association with selected independent variables was assessed.ResultsThe overall prevalence of frailty (95% CI was 47% (39-55. Higher levels of frailty were seen in older age groups, women, those who were non-married, those with recent hospital admission, those with co-morbid conditions, those on more than five medications and those with lower forced expiratory volume and mini-mental state examination score. After adjustment in a multiple logistic regression model only age and gender were found to be independently associated with frailty.ConclusionA high prevalence of frailty was found amongst older Emiratis. Given that frailty is associated with adverse health outcomes and can be a means of identifying opportunities for intervention in clinical practice and health policy, further attention and consideration within professional and public health policy circles is needed.

  4. Fatigue strength ofcomposite wind turbine blade structures

    DEFF Research Database (Denmark)

    Ardila, Oscar Gerardo Castro

    Wind turbines are normally designed to withstand 20-30 years of life. During this period, the blades, which are the main rotating structures of a wind turbine, are subjected to high fluctuating load conditions as a result of a combination of gravity, inertia, and aeroelastic forces. For this reason......, fatigue is one of the foremost concerns during the design of these structures. However, current standard fatigue methods used for designing wind turbine blades seem not to be completely appropriate for these structures because they are still based on methods developed for metals and not for composite...... materials from which the blades are made. In this sense, the aim of this work is to develop more accurate and reliable fatigue-life prediction models for composite wind turbine blades. In this project, two types of fatigue models are implemented: fatigue-life models and damage mechanics models. In the first...

  5. Blade Vibration Measurement System for Unducted Fans

    Science.gov (United States)

    Marscher, William

    2014-01-01

    With propulsion research programs focused on new levels of efficiency and noise reduction, two avenues for advanced gas turbine technology are emerging: the geared turbofan and ultrahigh bypass ratio fan engines. Both of these candidates are being pursued as collaborative research projects between NASA and the engine manufacturers. The high bypass concept from GE Aviation is an unducted fan that features a bypass ratio of over 30 along with the accompanying benefits in fuel efficiency. This project improved the test and measurement capabilities of the unducted fan blade dynamic response. In the course of this project, Mechanical Solutions, Inc. (MSI) collaborated with GE Aviation to (1) define the requirements for fan blade measurements; (2) leverage MSI's radar-based system for compressor and turbine blade monitoring; and (3) develop, validate, and deliver a noncontacting blade vibration measurement system for unducted fans.

  6. Doctor Blade-Coated Polymer Solar Cells

    KAUST Repository

    Cho, Nam Chul

    2016-10-25

    In this work, we report polymer solar cells based on blade-coated P3HT:PC71BM and PBDTTT-EFT:PC71BM bulk heterojunction photoactive layers. Enhanced power conversion efficiency of 2.75 (conventional structure) and 3.03% (inverted structure) with improved reproducibility was obtained from blade-coated P3HT:PC71BM solar cells, compared to spin-coated ones. Furthermore, by demonstrating 3.10% efficiency flexible solar cells using blade-coated PBDTTT-EFT:PC71BM films on the plastic substrates, we suggest the potential applicability of blade coating technique to the high throughput roll-to-roll fabrication systems.

  7. The 52-inch last-stage blades for steam turbines

    International Nuclear Information System (INIS)

    Suzuki, Atsuhide; Hisa, Shoichi; Nagao, Shin-ichiro; Ogata, Hisao

    1986-01-01

    The last-stage blades (LSB) of steam turbines are one of the most important components determining the plant's maximum capacity and efficiency. The development of LSBs necessitates high-technology including advanced methods of analyses and verifications as well as ample accumulation of technical data. The 52-inch LSB recently developed by Toshiba has raised nuclear power plant's capacity up to 1,300 ∼ 1,800 MW, has effected compact design of turbine units, and has improved thermal efficiency, keeping high reliability. (author)

  8. Blade design and performance analysis on the horizontal axis tidal current turbine for low water level channel

    International Nuclear Information System (INIS)

    Chen, C C; Choi, Y D; Yoon, H Y

    2013-01-01

    Most tidal current turbine design are focused on middle and large scale for deep sea, less attention was paid in low water level channel, such as the region around the islands, coastal seas and rivers. This study aims to develop a horizontal axis tidal current turbine rotor blade which is applicable to low water level island region in southwest of Korea. The blade design is made by using BEMT(blade element momentum theory). The section airfoil profile of NACA63-415 is used, which shows good performance of lift coefficient and drag coefficient. Power coefficient, pressure and velocity distributions are investigated according to TSR by CFD analysis

  9. 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.

  10. High efficiency turbine blade coatings

    Energy Technology Data Exchange (ETDEWEB)

    Youchison, Dennis L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Gallis, Michail A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2014-06-01

    The development of advanced thermal barrier coatings (TBCs) of yttria stabilized zirconia (YSZ) that exhibit lower thermal conductivity through better control of electron beam - physical vapor deposition (EB-PVD) processing is of prime interest to both the aerospace and power industries. This report summarizes the work performed under a two-year Lab-Directed Research and Development (LDRD) project (38664) to produce lower thermal conductivity, graded-layer thermal barrier coatings for turbine blades in an effort to increase the efficiency of high temperature gas turbines. This project was sponsored by the Nuclear Fuel Cycle Investment Area. Therefore, particular importance was given to the processing of the large blades required for industrial gas turbines proposed for use in the Brayton cycle of nuclear plants powered by high temperature gas-cooled reactors (HTGRs). During this modest (~1 full-time equivalent (FTE)) project, the processing technology was developed to create graded TBCs by coupling ion beam-assisted deposition (IBAD) with substrate pivoting in the alumina-YSZ system. The Electron Beam - 1200 kW (EB-1200) PVD system was used to deposit a variety of TBC coatings with micron layered microstructures and reduced thermal conductivity below 1.5 W/m.K. The use of IBAD produced fully stoichiometric coatings at a reduced substrate temperature of 600°C and a reduced oxygen background pressure of 0.1 Pa. IBAD was also used to successfully demonstrate the transitioning of amorphous PVD-deposited alumina to the -phase alumina required as an oxygen diffusion barrier and for good adhesion to the substrate Ni2Al3 bondcoat. This process replaces the time consuming thermally grown oxide formation required before the YSZ deposition. In addition to the process technology, Direct Simulation Monte Carlo plume modeling and spectroscopic characterization of the PVD plumes were performed. The project consisted of five tasks. These included the

  11. Experimental and Computational Investigation of Triple-rotating Blades in a Mower Deck

    Science.gov (United States)

    Chon, Woochong; Amano, Ryoichi S.

    Experimental and computational studies were performed on the 1.27m wide three-spindle lawn mower deck with side discharge arrangement. Laser Doppler Velocimetry was used to measure the air velocity at 12 different sections under the mower deck. The high-speed video camera test provided valuable visual evidence of airflow and grass discharge patterns. The strain gages were attached at several predetermined locations of the mower blades to measure the strain. In computational fluid dynamics work, computer based analytical studies were performed. During this phase of work, two different trials were attempted. First, two-dimensional blade shapes at several arbitrary radial sections were selected for flow computations around the blade model. Finally, a three-dimensional full deck model was developed and compared with the experimental results.

  12. Eddy current inspection of stationary blade rings

    International Nuclear Information System (INIS)

    Krzywosz, K.J.; Hastings, S.N.

    1994-01-01

    Stationary turbine blade rings in a US power plant have experienced chloride-induced cracking. Failure analysis determined two types of cracking mechanisms: corrosion fatigue cracking confined to the leading edge of the outer shroud; and stress corrosion cracking present all over the blade surface. Fluorescent dye penetrant is typically used to detect and size cracks. However, it requires cleaning the blade rings by sandblasting to obtain reliable inspection results. Sand blasting in turn requires sealing the lower half of the turbine housing to prevent sand from contaminating the rest of the power plant components. Furthermore, both the penetrant examination and the removal of the sand are time consuming and costly. An alternative NDE technique is desirable which requires no pre-cleaning of the blade and a quick go/no-go inspection with the capability of estimating the crack length. This paper presents an innovative eddy current technique which meets the desired objectives by incorporating the use of specially designed contoured scanners equipped with an array of pancake coils. A set of eddy current pancake coils housed in three different scanners is used to manually scan and inspect the convex side of the stationary blade rings. The pancake coils are operated in a transmit/receive mode using two separate eddy current instruments. This paper presents the inspection concept, including scanner and probe designs, and test results from the various stages of multiple blade rings

  13. Applied modal analysis of wind turbine blades

    Energy Technology Data Exchange (ETDEWEB)

    Broen Pedersen, H.; Dahl Kristensen, O.J.

    2003-02-01

    In this project modal analysis has been used to determine the natural frequencies, damping and the mode shapes for wind turbine blades. Different methods to measure the position and adjust the direction of the measuring points are discussed. Different equipment for mounting the accelerometers are investigated and the most suitable are chosen. Different excitation techniques are tried during experimental campaigns. After a discussion the pendulum hammer were chosen, and a new improved hammer was manufactured. Some measurement errors are investigated. The ability to repeat the measured results is investigated by repeated measurement on the same wind turbine blade. Furthermore the flexibility of the test set-up is investigated, by use of accelerometers mounted on the flexible adapter plate during the measurement campaign. One experimental campaign investigated the results obtained from a loaded and unloaded wind turbine blade. During this campaign the modal analysis are performed on a blade mounted in a horizontal and a vertical position respectively. Finally the results obtained from modal analysis carried out on a wind turbine blade are compared with results obtained from the Stig Oeyes blade{sub E}V1 program. (au)

  14. Cross-Sectional Multi-Center Study of Patients with Urea Cycle Disorders in the United States

    Science.gov (United States)

    Tuchman, Mendel; Lee, Brendan; Lichter-Konecki, Uta; Summar, Marshall L.; Yudkoff, Marc; Cederbaum, Stephen D.; Kerr, Douglas S.; Diaz, George A.; Seashore, Margaretta R.; Lee, Hye-Seung; McCarter, Robert J.; Krischer, Jeffrey P.; Batshaw, Mark L.

    2008-01-01

    Inherited urea cycle disorders comprise eight disorders (UCD), each caused by a deficiency of one of the protein that is essential for ureagenesis. We report on a cross sectional investigation to determine clinical and laboratory characteristics of patients with UCD in the United States. The data used for the analysis was collected at the time of enrollment of individuals with inherited UCD into a longitudinal observation study. The study has been conducted by the Urea Cycle Disorders Consortium (UCDC) within the Rare Diseases Clinical Research Network (RDCRN) funded by the National Institutes of Health. One hundred eighty three patients were enrolled into the study. Ornithine transcarbamylase (OTC) deficiency was the most frequent disorder (55%), followed by argininosuccinic aciduria (17%) and citrullinemia (11%). 79% of the participants were white (16% Latinos), and 6% were African American. Intellectual and developmental disabilities were reported in 39% with learning disabilities (35%) and half had abnormal neurological examination. 63% were on a protein restricted diet, 37% were on Na-phenylbutyrate and 5% were on Na-benzoate. 45% of OTC deficient patients were on L-citrulline, while most patients with citrullinemia (58%) and argininosuccinic (79%) were on L-arginine. Plasma levels of branched-chain amino acids were reduced in patients treated with ammonia scavenger drugs. Plasma glutamine levels were higher in proximal UCD disorders and in the neonatal type disease. The RDCRN allows comprehensive analyses of rare inherited UCD, their frequencies and current medical practices. PMID:18562231

  15. MODIFICATION OF RECIPES USED IN THE BLEACHING SECTION OF THE FINISHING PLANT OF THE TEXTILE UNIT "DESEMBARCO DEL GRANMA”

    Directory of Open Access Journals (Sweden)

    Isabel Cabrera Estada

    2017-07-01

    Full Text Available The Textile Basic Unit (BU “Desembarco del Granma” of Villa Clara is one of the most important textile industries in Cuba, it is responsible for the provision of a wide variety of fabrics, threads and surgical gauze to various sectors of the country. In the finishing plant of the BU "Desembarco del Granma" a production that meets the parameters set is achieved, but this requires the use of large volumes of costly chemicals and with negative impacts on the environment. To solve this problem an investigation was carried out to evaluate the modification of some of the recipes used in the bleaching section of the finishing plant of the BU "Desembarco del Granma". The results obtained were processed with the Statgraphics software. When the caustic soda is decreased from 60g/L to 40g/L, and it is analyzed the capillarity of warp, it was confirmed that there is no significant difference between the average of the two samples, for a 95,0 % of confidence level; but there were differences between the variances; when analyzing the fabric capillarity it was found that there is no significant difference between the average and the variance of the two samples for a 95,0 % of confidence level. With such modification it is saved 241,4 $/day, by concept of decrease of soda used. The hydrogen peroxide cannot be reduced because it affects the white degree of the fabric.

  16. Coping behavior and risk and resilience stress factors in French regional emergency medicine unit workers: a cross-sectional survey.

    Science.gov (United States)

    Lala, A I; Sturzu, L M; Picard, J P; Druot, F; Grama, F; Bobirnac, G

    2016-01-01

    The Emergency Department (ED) has the highest workload in a hospital, offering care to patients in their most acute state of illness, as well as comforting their families and tending to stressful situations of the physical and psychological areal. Method. A cross-sectional survey of 366 Emergency Unit staff members including medical doctors, medical residents, medical nurses and ward aids, was undergone. Study participants came from four periphery hospitals in the Moselle Department of Eastern France with similar workforce and daily patient loads statistics. The instruments used were the Perceived Stress Scale PSS-10 and the Brief COPE questionnaire. Conclusions. Perceived work overload and overall stress is strongly related to work hours and tend to have a stronger influence on doctors than on the nursing staff. Substance use is a common coping method for medical interns, consistent with prior research. The regular assessment of the ED staff perception of stress and stress related factors is essential to support organizational decisions in order to promote a better work environment and better patient care.

  17. Breast cancer screening awareness, knowledge, and practice among arab women in the United Arab Emirates: a cross-sectional survey.

    Directory of Open Access Journals (Sweden)

    Yusra E Elobaid

    Full Text Available BACKGROUND: Breast cancer screening can reduce morbidity and mortality and improve the survival rate for this malignancy. Low participation in screening programs has been attributable to many factors including lack of knowledge. The aim of this study was to assess breast cancer screening knowledge, attitudes and practices among women of screening age (≥40 years old in the city of Al Ain, United Arab Emirates (UAE. METHODS: A cross-sectional survey was conducted in 2013 using the Breast Cancer Awareness Measure (CAM. Four out of twelve cultural and religious community centers in Al Ain city were randomly selected. Two hundred and forty seven women were interviewed. Chi Square test and regression analysis were used to analyze the data. RESULTS: Despite the increase in the uptake of screening modalities in our study group, a lack of knowledge about breast cancer screening is still evident. Almost half (44.8% of women who never had a Clinical Breast Exam (CBE and 44.1% of women who never had a mammography expressed a lack of knowledge about the existence of these screening techniques. Nearly one third of the participants interpreted the presence of a breast lump incorrectly and, moreover, expressed fewer worries about the nature of the lump than would normally be expected. CONCLUSIONS: The National screening program needs to be improved and directed towards more efficient and targeted utilization of resources. Healthcare professionals play a major role in alerting women to the importance of periodic screening.

  18. Systemic risk score evaluation in ischemic stroke patients (SCALA): a prospective cross sectional study in 85 German stroke units.

    Science.gov (United States)

    Weimar, Christian; Goertler, Michael; Röther, Joachim; Ringelstein, E Bernd; Darius, Harald; Nabavi, Darius Günther; Kim, In-Ha; Theobald, Karlheinz; Diener, Han-Christoph

    2007-11-01

    Stratification of patients with transient ischemic attack (TIA) or ischemic stroke (IS) by risk of recurrent stroke can contribute to optimized secondary prevention. We therefore aimed to assess cardiovascular risk factor profiles of consecutive patients hospitalized with TIA/IS to stratify the risk of recurrent stroke according to the Essen Stroke Risk Score (ESRS) and of future cardiovascular events according to the ankle brachial index (ABI) as a marker of generalized atherosclerosis In this cross-sectional observational study, 85 neurological stroke units throughout Germany documented cardiovascular risk factor profiles of 10 consecutive TIA/IS patients on standardized questionnaires. Screening for PAD was done with Doppler ultrasonography to calculate the ABI. A total of 852 patients (57% men) with a mean age of 67+/-12.4 years were included of whom 82.9 % had IS. The median National Institutes of Health stroke sum score was 4 (TIA: 1). Arterial hypertension was reported in 71%, diabetes mellitus in 26%, clinical PAD in 10%, and an ABI or = 3 was observed in 58%, which in two previous retrospective analyses corresponded to a recurrent stroke risk of > or = 4%/year. The correlation between the ESRS and the ABI was low (r = 0.21). A high proportion of patients had asymptomatic atherosclerotic disease and a considerable risk of recurrent stroke according to the ABI and ESRS category. The prognostic accuracy as well as the potential benefit of various risk stratification scores in secondary stroke prevention require validation in a larger prospective study.

  19. Diamond blade grinding as a means for removing surface contamination from concrete

    International Nuclear Information System (INIS)

    Lynch, T.W.

    1980-01-01

    The use of a highway grinding unit for the decontamination of a 5,000 square foot surface is described. The type of equipment presently in use is described. Performance characteristics, waste collection and water usage are commented on. Variables in blade design are discussed. Feasibility of the grinding technique for water soluble contaminants and vertical surfaces is referred to

  20. GUIDE BLADE FOR AN OVERFLOW STRUCTURE TO BE PLACED ON A VESSEL

    DEFF Research Database (Denmark)

    2017-01-01

    contact surface (4), the primary contact surface having an edge (2) configured for abutting an overflow structure (100) and at least one free edge, wherein the guide blade is configured for being attachable to a unit to be arrange on or in an inlet (109) of an overflow structure or directly...

  1. Analysis of Pressure Fluctuations in a Prototype Pump-Turbine with Different Numbers of Runner Blades in Turbine Mode

    Directory of Open Access Journals (Sweden)

    Deyou Li

    2018-06-01

    Full Text Available In pump-turbines, high pressure fluctuation is one of the crucial instabilities, which is harmful to the stable and effective operation of the entire unit. Extensive studies have been carried out to investigate pressure fluctuations (amplitude and frequency at specific locations. However, limited research was conducted on the distribution of pressure fluctuations in turbine mode in a pump-turbine, as well as the influence of the number of runner blades on pressure fluctuations. Hence, in this study, three dimensional numerical simulations were performed to predict the distribution of pressure fluctuations with different numbers of runner blades in a prototype pump-turbine in turbine mode using the shear stress transport (SST k-ω turbulence model. Three operating points with the same hydraulic head and different mass flow rates were simulated. The distribution of pressure fluctuation components of blade passing frequency and its harmonics in the direction along the whole flow path, as well as along the circumferential direction, was presented. The mass flow rate and number of runner blades have great influence on the distribution of pressure fluctuations, especially at blade passing frequency along circumferential direction. The mass flow rate mainly affects the position of peak pressure fluctuations, while the number of runner blades mainly changes the number of peak pressure fluctuations. Additionally, the number of runner blades influences the dominant frequencies of pressure fluctuations especially in the spiral casing and draft tube.

  2. Integrity assessment of stationary blade ring for nuclear power plant

    International Nuclear Information System (INIS)

    Park, Jung Yong; Chung, Yong Keun; Park, Jong Jin; Kang, Yong Ho

    2004-01-01

    The inner side between HP stationary blades in no.1 turbine of nuclear power plant A is damaged by the FAC(Flow Assisted Corrosion) which is exposed to moisture. For many years the inner side is repaired by welding the damaged part, however, the FAC continues to deteriorate the original material of the welded blade ring. In this study, we have two stages to verify the integrity of stationary blade ring in nuclear power plant A. In the stage I, replication of blade ring is performed to survey the microstructure of blade ring. In the stage II, the stress analysis of blade ring is performed to verify the structural safety of blade ring. Throughout the two stages analysis of blade ring, the stationary blade ring had remained undamaged

  3. A New Method for Horizontal Axis Wind Turbine (HAWT Blade Optimization

    Directory of Open Access Journals (Sweden)

    Mohammadreza Mohammadi

    2016-02-01

    Full Text Available Iran has a great potential for wind energy. This paper introduces optimization of 7 wind turbine blades for small and medium scales in a determined wind condition of Zabol site, Iran, where the average wind speed is considered 7 m /s. Considered wind turbines are 3 bladed and radius of 7 case study turbine blades are 4.5 m, 6.5 m, 8 m, 9 m, 10 m, 15.5 m and 20 m. As the first step, an initial design is performed using one airfoil (NACA 63-215 across the blade. In the next step, every blade is divided into three sections, while the 20 % of first part of the blade is considered as root, the 5% of last the part is considered as tip and the rest of the blade as mid part. Providing necessary input data, suitable airfoils for wind turbines including 43 airfoils are extracted and their experimental data are entered in optimization process. Three variables in this optimization problem would be airfoil type, attack angle and chord, where the objective function is maximum output torque. A MATLAB code was written for design and optimization of the blade, which was validated with a previous experimental work. In addition, a comparison was made to show the effect of optimization with two variables (airfoil type and attack angle versus optimization with three variables (airfoil type, attack angle and chord on output torque increase. Results of this research shows a dramatic increase in comparison to initial designed blade with one airfoil where two variable optimization causes 7.7% to 22.27 % enhancement and three variable optimization causes 17.91% up to 24.48% rise in output torque .Article History: Received Oct 15, 2015; Received in revised form January 2, 2016; Accepted January 14, 2016; Available online How to Cite This Article: Mohammadi, M., Mohammadi, A. and Farahat, S. (2016 A New Method for Horizontal Axis Wind Turbine (HAWT Blade Optimization. Int. Journal of Renewable Energy Development, 5(1,1-8. http://dx.doi.org/10.14710/ijred.5.1.1-8

  4. Model predictive control of trailing edge flaps on a wind turbine blade

    Energy Technology Data Exchange (ETDEWEB)

    Castaignet, D.B.

    2011-11-15

    Trailing edge flaps on wind turbine blades have been investigated for several years. Aero-servoelastic simulations carried out with different simulation tools, trailing edge flaps configurations and controller designs proved that trailing edge flaps are a suitable solution for reducing some of the wind turbine fatigue and extreme loads. This potential was confirmed with wind tunnel tests made on blade sections with trailing edge flaps and on a scaled two-bladed wind turbine in a wind tunnel. The work presented in this thesis includes a full-scale test run on a Vestas V27 wind turbine equipped with three trailing edge flaps on one blade, located on DTU's Risoe Campus in Roskilde, Denmark. This thesis is divided into three parts: the controller design, results from simulations, and results from the experiments. The trailing edge flaps controller designed for this project is based on a frequency-weighted model predictive control, tuned in order to target only the flapwise blade root loads at the frequencies contributing the most to blade root fatigue damage (the 1P, 2P and 3P frequencies), and to avoid unnecessary wear and tear of the actuators at high frequencies. A disturbance model consisting in periodic disturbances at the rotor speed harmonic frequencies and a quasi-steady input disturbance is aggregated to an analytical model of a spinning blade with trailing edge flaps. Simulations on a multi-megawatt wind turbine show the potential of the trailing edge flaps to reduce the flapwise blade root fatigue loads by 23%, but also the main shaft and the tower fatigue loads by up to 32%. Extreme loads during normal production also benefit from the trailing edge flaps. At last, the same controller was run on the Vestas V27 wind turbine located at the Risoe Campus of the Technical University of Denmark, in Roskilde, Denmark. One blade of the turbine was equipped with three independent trailing edge flaps. In spite of the failure of several sensors and actuators, the

  5. NedWind 25 Blade Testing at NREL for the European Standards Measurement and Testing Program

    Energy Technology Data Exchange (ETDEWEB)

    Larwood, S.; Musial, W.; Freebury, G.; Beattie, A.G.

    2001-04-19

    In the mid-90s the European community initiated the Standards, Measurements, and Testing (SMT) program to harmonize testing and measurement procedures in several industries. Within the program, a project was carried out called the European Wind Turbine Testing Procedure Development. The second part of that project, called Blade Test Methods and Techniques, included the United States and was devised to help blade-testing laboratories harmonize their testing methods. This report provides the results of those tests conducted by the National Renewable Energy Laboratory.

  6. Distribution of defects in wind turbine blades and reliability assessment of blades containing defects

    DEFF Research Database (Denmark)

    Stensgaard Toft, Henrik; Branner, Kim; Berring, Peter

    2009-01-01

    on the assumption that one error in the production process tends to trigger several defects. For both models additional information about number, type and size of the defects is included as stochastic variables. The probability of failure for a wind turbine blade will not only depend on variations in the material......In the present paper two stochastic models for the distribution of defects in wind turbine blades are proposed. The first model assumes that the individual defects are completely randomly distributed in the blade. The second model assumes that the defects occur in clusters of different size based...... properties and the load but also on potential defects in the blades. As a numerical example the probability of failure is calculated for the main spar both with and without defects in terms of delaminations. The delaminations increase the probability of failure compared to a perfect blade, but by applying...

  7. Low Speed Technology for Small Turbine Development Reaction Injection Molded 7.5 Meter Wind Turbine Blade

    Energy Technology Data Exchange (ETDEWEB)

    David M. Wright; DOE Project Officer - Keith Bennett

    2007-07-31

    An optimized small turbine blade (7.5m radius) was designed and a partial section molded with the RIM (reaction-injection molded polymer) process for mass production. The intended market is for generic three-bladed wind turbines, 100 kilowatts or less, for grid-assist end users with rural and semi-rural sites, such as the farm/ranch market, having low to moderate IEC Class 3-4 wind regimes. This blade will have substantial performance improvements over, and be cheaper than, present-day 7.5m blades. This is made possible by the injection-molding process, which yields high repeatability, accurate geometry and weights, and low cost in production quantities. No wind turbine blade in the 7.5m or greater size has used this process. The blade design chosen uses a RIM skin bonded to a braided infused carbon fiber/epoxy spar. This approach is attractive to present users of wind turbine blades in the 5-10m sizes. These include rebladeing California wind farms, refurbishing used turbines for the Midwest farm market, and other manufacturers introducing new turbines in this size range.

  8. Design and initial testing of a one-bladed 30-meter-diameter rotor on the NASA/DOE mod-O wind turbine

    Science.gov (United States)

    Corrigan, R. D.; Ensworth, C. B. F.

    1986-01-01

    The concept of a one-bladed horizontal-axis wind turbine has been of interest to wind turbine designers for many years. Many designs and economic analyses of one-bladed wind turbines have been undertaken by both United States and European wind energy groups. The analyses indicate significant economic advantages but at the same time, significant dynamic response concerns. In an effort to develop a broad data base on wind turbine design and operations, the NASA Wind Energy Project Office has tested a one-bladed rotor at the NASA/DOE Mod-O Wind Turbine Facility. This is the only known test on an intermediate-sized one-bladed rotor in the United States. The 15.2-meter-radius rotor consists of a tip-controlled blade and a counterweight assembly. A rigorous test series was conducted in the Fall of 1985 to collect data on rotor performance, drive train/generator dynamics, structural dynamics, and structural loads. This report includes background information on one-bladed rotor concepts, and Mod-O one-bladed rotor test configuration, supporting design analysis, the Mod-O one-blade rotor test plan, and preliminary test results.

  9. Spacer grid with mixing blades for nuclear fuel assembly

    International Nuclear Information System (INIS)

    Noailly, J.

    1986-01-01

    The spacer grid for nuclear fuel assembly has two sets of intersecting metal plates provided with blades and defining cells. The plates are fitted only with half-blades associated with a single grid opening. The half-blades of adjacent cells are arranged at 90deg C to each other and each plate has at most one half-blade at each corner of a cell. The invention concerns fuel assemblies of pressurized water reactors. The blades arranged on a single side of the plate provide a good hydraulic uniformity. The invention provides a uniform distribution of blades (and thus of absorbing material in each hydraulic cell) [fr

  10. Design, development and performance of a disk plow combined with rotary blades

    International Nuclear Information System (INIS)

    Hashemi, A; Ahmad, D; Othman, J; Sulaiman, S

    2012-01-01

    Disk plow combined with rotary blades, defined as comboplow, is used for soil preparation for planting. The comboplow includes four units: Chassis, concave disk, transmission system and rotary blades. A multiple tillage operation is reduced in a single pass resulting in a potential reduction of soil compaction, labor, fuel cost and saving in time. The comboplow was tested at University Putra Malaysia Research Park, Serdang, Selangor, Malaysia, on three different plots of 675 m 2 in the year 2010/2011. The treatments were three types of blade [(straight (S),curved (c) and L-shaped)] and three rotary speeds (130,147and 165 rpm). The parameters were Mean Weight Diameter Dry Basis (MWD d ), Mean weight Diameter Wet Basis (MWD W ), Aggregate Stability Index (SI) and Instability Index (II).

  11. 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

  12. 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.

  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. Study of a wave power generator system using an air turbine having improved J-shaped blades; Kairyo J gatayoku kuki turbine wo mochiita haryoku hatsuden sochi no kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Honma, T; Omata, K; Kojima, N [Meiji University, Tokyo (Japan)

    1997-11-25

    An improved J-shaped blade, in which a J-shaped blade is combined with a small-size Savonius blade, has been developed, to further improve efficiency of an air turbine for wave power generator systems. A prototype model of stationary wave power generator has been developed using the improved blade, to confirm its power generation characteristics by tests in a water tank and small-scale ocean tests. The results are compared with the characteristics of the units with conventional blades. The air turbine unit with the improved blade shows an efficiency of 13 to 35%, which is higher by 10 to 20% than that of the turbine with a J-shaped blade and by 20 to 70% than that of the one with a Savonius blade, more noted at low speed of rotation. It is therefore considered that the turbine with the improved blade is suited for sea areas having a relatively low wave height. It is also considered that efficiency can be further enhanced, when one or more guide vanes are provided around the blade. 2 refs., 12 figs.

  15. Modal analysis of wind turbine blades

    Energy Technology Data Exchange (ETDEWEB)

    Larsen, G.C.; Hansen, M.H.; Baumgart, A.; Carlen, I.

    2002-02-01

    The modal analysis technique has been used to identify essential dynamic properties of wind turbine blades like natural frequencies, damping characteristics and mode shapes. Different experimental procedures have been considered, and the most appropriate of these has been selected. Although the comparison is based on measurements on a LM 19 m blade, the recommendations given are believed to be valid for other wind turbine blades as well. The reliability of the selected experimental analysis has been quantified by estimating the unsystematic variations in the experimental findings. Satisfactory results have been obtained for natural frequencies, damping characteristics and for the dominating deflection direction of the investigated mode shapes. For the secondary deflection directions, the observed experimental uncertainty may be considerable - especially for the torsional deflection. The experimental analysis of the LM 19 m blade has been compared with results from a state-of-the-art FE-modeling of the same blade. For some of the higher modes substantial discrepancies between the natural frequencies originating from the FE-modeling and the modal analysis, respectively, are observed. In general the qualitative features of measured and computed modes shapes are in good agreement. However, for the secondary deflection directions, substantial deviations in the absolute values may occur (when normalizing with respect to the primary deflection direction). Finally, suggestions of potential future improvements of the experimental procedure are discussed. (au)

  16. 3X-100 blade field test.

    Energy Technology Data Exchange (ETDEWEB)

    Zayas, Jose R.; Johnson, Wesley D.

    2008-03-01

    In support of a Work-For-Other (WFO) agreement between the Wind Energy Technology Department at Sandia National Laboratories and 3TEX, one of the three Micon 65/13M wind turbines at the USDA Agriculture Research Service (ARS) center in Bushland, Texas, has been used to test a set of 9 meter wind turbine blades, manufactured by TPI composites using the 3TEX carbon material for the spar cap. Data collected from the test has been analyzed to evaluate both the aerodynamic performance and the structural response from the blades. The blades aerodynamic and structural performance, the meteorological inflow and the wind turbine structural response has been monitored with an array of 57 instruments: 15 to characterize the blades, 13 to characterize inflow, and 15 to characterize the time-varying state of the turbine. For the test, data was sampled at a rate of 40 Hz using the ATLAS II (Accurate GPS Time-Linked Data Acquisition System) data acquisition system. The system features a time-synchronized continuous data stream and telemetered data from the turbine rotor. This paper documents the instruments and infrastructure that have been developed to monitor these blades, turbines and inflow, as well as both modeling and field testing results.

  17. 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.

  18. Individual blade pitch for yaw control

    International Nuclear Information System (INIS)

    Navalkar, S T; Van Wingerden, J W; Van Kuik, G A M

    2014-01-01

    Individual pitch control (IPC) for reducing blade loads has been investigated and proven successful in recent literature. For IPC, the multi-blade co-ordinate (MBC) transformation is used to process the blade load signals from the rotating to a stationary frame of reference. In the stationary frame of reference, the yaw error of a turbine can be appended to generate IPC actions that are able to achieve turbine yaw control for a turbine in free yaw. In this paper, IPC for yaw control is tested on a high-fidelity numerical model of a commercially produced wind turbine in free yaw. The tests show that yaw control using IPC has the distinct advantage that the yaw system loads and support structure loading are substantially reduced. However, IPC for yaw control also shows a reduction in IPC blade load reduction potential and causes a slight increase in pitch activity. Thus, the key contribution of this paper is the concept demonstration of IPC for yaw control. Further, using IPC for yaw as a tuning parameter, it is shown how the best trade-off between blade loading, pitch activity and support structure loading can be achieved for wind turbine design

  19. Computational Modelling of Materials for Wind Turbine Blades: Selected DTUWind Energy Activities

    DEFF Research Database (Denmark)

    Mikkelsen, Lars Pilgaard; Mishnaevsky, Leon

    2017-01-01

    Computational and analytical studies of degradation of wind turbine blade materials at the macro-, micro-, and nanoscale carried out by the modelling team of the Section Composites and Materials Mechanics, Department of Wind Energy, DTU, are reviewed. Examples of the analysis of the microstructural...... effects on the strength and fatigue life of composites are shown. Computational studies of degradation mechanisms of wind blade composites under tensile and compressive loading are presented. The effect of hybrid and nanoengineered structures on the performance of the composite was studied...

  20. Computational Modelling of Materials for Wind Turbine Blades: Selected DTU Wind Energy Activities.

    Science.gov (United States)

    Mikkelsen, Lars Pilgaard; Mishnaevsky, Leon

    2017-11-08

    Computational and analytical studies of degradation of wind turbine blade materials at the macro-, micro-, and nanoscale carried out by the modelling team of the Section Composites and Materials Mechanics, Department of Wind Energy, DTU, are reviewed. Examples of the analysis of the microstructural effects on the strength and fatigue life of composites are shown. Computational studies of degradation mechanisms of wind blade composites under tensile and compressive loading are presented. The effect of hybrid and nanoengineered structures on the performance of the composite was studied in computational experiments as well.

  1. 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...

  2. Influence of water–air ratio on the heat transfer and creep life of a high pressure gas turbine blade

    International Nuclear Information System (INIS)

    Eshati, S.; Abu, A.; Laskaridis, P.; Khan, F.

    2013-01-01

    An analytical model to investigate the influence of Water–Air Ratio (WAR) on turbine blade heat transfer and cooling processes (and thus the blade creep life) of industrial gas turbines is presented. The effects of WAR are emphasised for the modelling of the gas properties and the subsequent heat transfer process. The approach considers convective/film cooling and includes the influence of a thermal barrier coating. In addition, the approach is based on the thermodynamic outputs of a gas turbine performance simulation, heat transfer model, as well as a method that accounts for the changes in the properties of moist air as a function of WAR. For a given off-design point, the variation of WAR (0.0–0.10) was investigated using the heat transfer model. Results showed that with increasing WAR the blade inlet coolant temperature reduced along the blade span. The blade metal temperature at each section was reduced as WAR increased, which in turn increased the blade creep life. The increase in WAR increased the specific heat of the coolant and increased the heat transfer capacity of the coolant air flow. The model can be implemented by using the thermodynamic cycle of the engine, without knowing the turbine cooling details in the conceptual design stage. Also, this generic method assists the end user to understand the effect of operating conditions and design parameter on the creep life of a high pressure turbine blade. -- Highlights: • The influence of WAR on gas turbine blade heat transfer and creep life is examined. • Coolant specific heat capacity is the key property affected by changes in WAR. • Increase in WAR reduces the coolant and metal temperature along the blade span. • Creep life increases with increase in WAR even if ambient temperature is increased

  3. Piezoelectric Vibration Damping Study for Rotating Composite Fan Blades

    Science.gov (United States)

    Min, James B.; Duffy, Kirsten P.; Choi, Benjamin B.; Provenza, Andrew J.; Kray, Nicholas

    2012-01-01

    Resonant vibrations of aircraft engine blades cause blade fatigue problems in engines, which can lead to thicker and aerodynamically lower performing blade designs, increasing engine weight, fuel burn, and maintenance costs. In order to mitigate undesirable blade vibration levels, active piezoelectric vibration control has been investigated, potentially enabling thinner blade designs for higher performing blades and minimizing blade fatigue problems. While the piezoelectric damping idea has been investigated by other researchers over the years, very little study has been done including rotational effects. The present study attempts to fill this void. The particular objectives of this study were: (a) to develop and analyze a multiphysics piezoelectric finite element composite blade model for harmonic forced vibration response analysis coupled with a tuned RLC circuit for rotating engine blade conditions, (b) to validate a numerical model with experimental test data, and (c) to achieve a cost-effective numerical modeling capability which enables simulation of rotating blades within the NASA Glenn Research Center (GRC) Dynamic Spin Rig Facility. A numerical and experimental study for rotating piezoelectric composite subscale fan blades was performed. It was also proved that the proposed numerical method is feasible and effective when applied to the rotating blade base excitation model. The experimental test and multiphysics finite element modeling technique described in this paper show that piezoelectric vibration damping can significantly reduce vibrations of aircraft engine composite fan blades.

  4. 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.

  5. Multi-scale simulation of single crystal hollow turbine blade manufactured by liquid metal cooling process

    Directory of Open Access Journals (Sweden)

    Xuewei Yan

    2018-02-01

    Full Text Available Liquid metal cooling (LMC process as a powerful directional solidification (DS technique is prospectively used to manufacture single crystal (SC turbine blades. An understanding of the temperature distribution and microstructure evolution in LMC process is required in order to improve the properties of the blades. For this reason, a multi-scale model coupling with the temperature field, grain growth and solute diffusion was established. The temperature distribution and mushy zone evolution of the hollow blade was simulated and discussed. According to the simulation results, the mushy zone might be convex and ahead of the ceramic beads at a lower withdrawal rate, while it will be concave and laggard at a higher withdrawal rate, and a uniform and horizontal mushy zone will be formed at a medium withdrawal rate. Grain growth of the blade at different withdrawal rates was also investigated. Single crystal structures were all selected out at three different withdrawal rates. Moreover, mis-orientation of the grains at 8 mm/min reached ~30°, while it was ~5° and ~15° at 10 mm/min and 12 mm/min, respectively. The model for predicting dendritic morphology was verified by corresponding experiment. Large scale for 2D dendritic distribution in the whole sections was investigated by experiment and simulation, and they presented a well agreement with each other. Keywords: Hollow blade, Single crystal, Multi-scale simulation, Liquid metal cooling

  6. 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.

  7. A combined piezoelectric composite actuator and its application to wing/blade tips

    Science.gov (United States)

    Ha, Kwangtae

    A novel combined piezoelectric-composite actuator configuration is proposed and analytically modeled in this work. The actuator is a low complexity, active compliant mechanism obtained by coupling a modified star cross sectional configuration composite beam with a helicoidal bimorph piezoelectric actuator coiled around it. This novel actuator is a good candidate as a hinge tension-torsion bar actuator for a helicopter rotor blade flap or blade tip and mirror rotational positioning. In the wing tip case, the tip deflection angle is different only according to the aerodynamic moment depending on the hinge position of the actuator along the chord and applied voltage because there is no centrifugal force. For an active blade tip subject to incompressible flow and 2D quasi steady airloads, its twist angle is related not only to aerodynamic moment and applied voltage but also to coupling terms, such as the trapeze effect and the tennis racquet effect. Results show the benefit of hinge position aft of the aerodynamic center, such that the blade tip response is amplified by airloads. Contrary to this effect, results also show that the centrifugal effects and inertial effect cause an amplitude reduction in the response. Summation of these effects determines the overall blade tip response. The results for a certain hinge position of Xh=1.5% chord aft of the quarter chord point proves that the tip deflection target design range of beta ∈ [-2,+2] can be achieved for all pitch angle configurations chosen.

  8. 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.

  9. 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.

  10. 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.

  11. Model predictive control of trailing edge flaps on a wind turbine blade

    DEFF Research Database (Denmark)

    Castaignet, Damien Bruno

    of the wind turbine fatigue and extreme loads. This potential was confirmed with wind tunnel tests made on blade sections with trailing edge flaps and on a scaled two-bladed wind turbine in a wind tunnel. The work presented in this thesis includes a full-scale test run on a Vestas V27 wind turbine equipped...... fatigue loads by 23%, but also the main shaft and the tower fatigue loads by up to 32%. Extreme loads during normal production also benefit from the trailing edge flaps. At last, the same controller was run on the Vestas V27 wind turbine located at the Risø Campus of the Technical University of Denmark......Trailing edge flaps on wind turbine blades have been investigated for several years. Aero-servoelastic simulations carried out with different simulation tools, trailing edge flaps configurations and controller designs proved that trailing edge flaps are a suitable solution for reducing some...

  12. The Brazier effect in wind turbine blades and its influence on design

    DEFF Research Database (Denmark)

    Jensen, Find Mølholt; Weaver, P.M.; Cecchini, L.S.

    2012-01-01

    Critical failure was observed in the shear web of a wind turbine blade during a full-scale testing. This failure occurred immediately before the ultimate failure and was partly caused by buckling and non-linear cross-sectional strain. Experimental values had been used to compare and validate both...... numerical and semi-analytical results in the analysis of the shear webs in the reinforced wind turbine blade. Only elastic material behaviour was analysed, and attention was primarily focused on the Brazier effect. The complex, geometrically non-linear and elastic stress–strain behaviour of the shear webs...... and the cap in compression were analysed using a balance of experimental, numerical and analytical approaches. It was noted that the non-linear distortion was caused by the crushing pressure derived from the Brazier effect. This Brazier pressure may have a significant impact on the design of new blades...

  13. Resonant vibration control of wind turbine blades

    DEFF Research Database (Denmark)

    Svendsen, Martin Nymann; Krenk, Steen; Høgsberg, Jan Becker

    2010-01-01

    . The efficiency of the resonant controller is demonstrated for a representative turbine blade exposed to turbulent wind loading. It is found that the present explicit tuning procedure yields close to optimal tuning, with very limited modal spill-over and effective reduction of the vibration amplitudes.......The paper deals with introduction of damping to specific vibration modes of wind turbine blades, using a resonant controller with acceleration feedback. The wind turbine blade is represented by three-dimensional, two-node finite elements in a local, rotating frame of reference. The element...... formulation accounts for arbitrary mass density distributions, general elastic crosssection properties and geometric stiffness effects due to internal stresses. A compact, linear formulation for aerodynamic forces with associated stiffness and damping terms is established and added to the structural model...

  14. Experimental development of a torsion arc blade type horizontal axis windmil; Nejire enko yokugata suihei jiku fusha no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Kojima, N. [Meiji Univ., Tokyo (Japan). Faculty of Scince and Technology

    1996-05-31

    To get more wind energy, longer rotating blades and higher towers of windmills are required. Therefore, the location of windmills is limited and the initial cost gets higher. In this study, a small size windmill which can generate electricity even in a city was developed and tested. A torsion arc blade type horizontal axis windmill was designed and the blade form, number and degree of distortion were investigated. Based on the results, a small windmill was made, rotation and generation tests were carried out and it was confirmed that the windmill could be used as a small scale wind power generation. The windmill is of simple construction having 6 arc blades and no high tower is required. This paper consists of 6 sections, i.e. Introduction, Windmill model, Tested windmill, Test facility and method, Test results and consideration, and Postscript. 2 refs., 18 figs., 1 tab.

  15. 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.

  16. 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

  17. Urban sprawl, obesity, and cancer mortality in the United States: cross-sectional analysis and methodological challenges.

    Science.gov (United States)

    Berrigan, David; Tatalovich, Zaria; Pickle, Linda W; Ewing, Reid; Ballard-Barbash, Rachel

    2014-01-06

    Urban sprawl has the potential to influence cancer mortality via direct and indirect effects on obesity, access to health services, physical activity, transportation choices and other correlates of sprawl and urbanization. This paper presents a cross-sectional analysis of associations between urban sprawl and cancer mortality in urban and suburban counties of the United States. This ecological analysis was designed to examine whether urban sprawl is associated with total and obesity-related cancer mortality and to what extent these associations differed in different regions of the US. A major focus of our analyses was to adequately account for spatial heterogeneity in mortality. Therefore, we fit a series of regression models, stratified by gender, successively testing for the presence of spatial heterogeneity. Our resulting models included county level variables related to race, smoking, obesity, access to health services, insurance status, socioeconomic position, and broad geographic region as well as a measure of urban sprawl and several interactions. Our most complex models also included random effects to account for any county-level spatial autocorrelation that remained unexplained by these variables. Total cancer mortality rates were higher in less sprawling areas and contrary to our initial hypothesis; this was also true of obesity related cancers in six of seven U.S. regions (census divisions) where there were statistically significant associations between the sprawl index and mortality. We also found significant interactions (p urban sprawl for total and obesity related cancer mortality in both sexes. Thus, the association between urban sprawl and cancer mortality differs in different regions of the US. Despite higher levels of obesity in more sprawling counties in the US, mortality from obesity related cancer was not greater in such counties. Identification of disparities in cancer mortality within and between geographic regions is an ongoing public

  18. Shifting tides in the emigration patterns of Canadian physicians to the United States: a cross-sectional secondary data analysis.

    Science.gov (United States)

    Freeman, Thomas R; Petterson, Stephen; Finnegan, Sean; Bazemore, Andrew

    2016-12-01

    The relative ease of movement of physicians across the Canada/US border has led to what is sometimes referred to as a 'brain drain' and previous analysis estimated that the equivalent of two graduating classes from Canadian medical schools were leaving to practice in the US each year. Both countries fill gaps in physician supply with international medical graduates (IMGs) so the movement of Canadian trained physicians to the US has international ramifications. Medical school enrolments have been increased on both sides of the border, yet there continues to be concerns about adequacy of physician human resources. This analysis was undertaken to re-examine the issue of Canadian physician migration to the US. We conducted a cross-sectional analysis of the 2015 American Medical Association (AMA) Masterfile to identify and locate any graduates of Canadian schools of medicine (CMGs) working in the United States in direct patient care. We reviewed annual reports of the Canadian Resident Matching Service (CaRMS); the Canadian Post-MD Education Registry (CAPER); and the Canadian Collaborative Centre for Physician Resources (C3PR). Beginning in the early 1990s the number of CMGs locating in the U.S. reached an all-time high and then abruptly dropped off in 1995. CMGs are going to the US for post-graduate training in smaller numbers and, are less likely to remain than at any time since the 1970's. This four decade retrospective found considerable variation in the migration pattern of CMGs to the US. CMGs' decision to emigrate to the U.S. may be influenced by both 'push' and 'pull' factors. The relative strength of these factors changed and by 2004, more CMGs were returning from abroad than were leaving and the current outflow is negligible. This study supports the need for medical human resource planning to assume a long-term view taking into account national and international trends to avoid the rapid changes that were observed. These results are of importance to medical

  19. Prevalence of Diabetes among Migrant Women and Duration of Residence in the United Arab Emirates: A Cross Sectional Study.

    Science.gov (United States)

    Shah, Syed M; Ali, Raghib; Loney, Tom; Aziz, Faisal; ElBarazi, Iffat; Al Dhaheri, Salma; Farooqi, M Hamed; Blair, Iain

    2017-01-01

    The prevalence rate of type 2 diabetes mellitus (T2DM) is one of the highest in United Arab Emirates (UAE), however data for the expatriate population is limited. This study aimed to identify the prevalence of T2DM amongst migrant women and test the hypothesis that acculturation (measured by years of residency) is associated with an increased risk of T2DM. This was a cross-sectional study and we recruited a representative sample (n = 599, 75% participation rate) of migrant women aged 18 years and over in Al Ain, UAE. The American Diabetes Association criteria were used to diagnose T2DM. An adapted WHO STEPS questionnaire was used to collect socio-demographic, lifestyle and clinical data. Logistic regression analysis was performed to identify correlates of T2DM including length of UAE residence. The mean age of participants was 34.1 (± 9.5) years. Of the study participants, based on HbA1C levels, 18.6% (95% CI: 13.9-24.4) had prediabetes and 10.7% (95% CI: 7.2-15.6) had T2DM. Prevalence of prediabetes was 8.5% for Filipinos, 16.7% for Arabs and 30.3% for South Asians. Similarly the prevalence of T2DM was 1.7% for Filipinos, 12.2% for Arabs and 16.7% for South Asians. Significant correlates of overall T2DM (measured and known diabetes) included length of UAE residence for more than 10 years (Adjusted Odds Ratio [AOR] 2.74, 95% CI: 1.21-6.20), age ≥40 years (AOR = 3.48, 95% CI: 1.53-7.87) and South Asian nationality (AOR 2.10, 95% CI: 0.94-4.70). Diabetes is a significant public health problem among migrant women in the UAE, particularly for South Asians. Longer length of residence in the UAE is associated with a higher prevalence of diabetes.

  20. Research overview on vibration damping of mistuned bladed disk assemblies

    Directory of Open Access Journals (Sweden)

    Liang ZHANG

    2016-04-01

    Full Text Available Bladed disk assemblies are very important parts in auto engine and gas turbine, and is widely used in practical engineering. The mistuning existing commonly in the bladed disk assemblies can destroy the vibration characteristics of the bladed disk assemblies, which is one of the reasons for the high cycle fatigue failure of bladed disk assemblies, so it is necessary to research how to reduce the vibration of the bladed disk assemblies. On the basis of the review of relevant research at home and abroad, the mistuning vibration mechanism of the bladed disk assemblies is introduced, and the main technical methods of the vibration damping of bladed disk assemblies are reviewed, such as artificially active mistuning, collision damping, friction damping and optimization of the blade position. Some future research directions are presented.

  1. Advances in wind turbine blade design and materials

    DEFF Research Database (Denmark)

    Wind energy is gaining critical ground in the area of renewable energy, with wind energy being predicted to provide up to 8% of the world’s consumption of electricity by 2021. Advances in wind turbine blade design and materials reviews the design and functionality of wind turbine rotor blades...... as well as the requirements and challenges for composite materials used in both current and future designs of wind turbine blades. Part one outlines the challenges and developments in wind turbine blade design, including aerodynamic and aeroelastic design features, fatigue loads on wind turbine blades......, and characteristics of wind turbine blade airfoils. Part two discusses the fatigue behavior of composite wind turbine blades, including the micromechanical modelling and fatigue life prediction of wind turbine blade composite materials, and the effects of resin and reinforcement variations on the fatigue resistance...

  2. Magnus wind turbines as an alternative to the blade ones

    International Nuclear Information System (INIS)

    Bychkov, N M; Dovgal, A V; Kozlov, V V

    2007-01-01

    Experimental and calculated data on a wind turbine equipped with rotating cylinders instead of traditional blades are reported. Optimal parameters and the corresponding operational characteristics of the windwheel are given in comparison with those of the blade wind turbines

  3. Computational method for the design of wind turbine blades

    Energy Technology Data Exchange (ETDEWEB)

    Vitale, A.J. [Instituto Argentino de Oceanografia, Camino La Carrindanga Km. 7.5, CC 804, B8000FWB Bahia Blanca (Argentina); Universidad Tecnologica Nacional Facultad Regional Bahia Blanca, GESE, 11 de Abril 461, B8000LMI Bahia Blanca (Argentina); Universidad Nacional del Sur, Dpto. de Ing. Electrica y de Computadoras, Av. Alem 1253, 8000 Bahia Blanca (Argentina); Rossi, A.P. [Universidad Tecnologica Nacional Facultad Regional Bahia Blanca, GESE, 11 de Abril 461, B8000LMI Bahia Blanca (Argentina); Universidad Nacional del Sur, Dpto. de Ing. Electrica y de Computadoras, Av. Alem 1253, 8000 Bahia Blanca (Argentina)

    2008-07-15

    Zeus Disenador was developed to design low-power, horizontal-axis wind turbine blades, by means of an iterative algorithm. With this software, it is possible to obtain the optimum blade shape for a wind turbine to satisfy energy requirements of an electric system with optimum rotor efficiency. The number of blades, the airfoil curves and the average wind velocity can be specified by the user. The user can also request particular edge conditions for the width of the blades and for the pitch angle. Results are provided in different windows. Two- and three-dimensional graphics show the aspect of the resultant blade. Numerical results are displayed for blade length, blade surface, pitch angle variation along the blade span, rotor angular speed, rotor efficiency and rotor output power. Software verifications were made by comparing rotor power and rotor efficiency for different designs. Results were similar to those provided by commercial wind generator manufacturers. (author)

  4. Wind blade spar cap and method of making

    Science.gov (United States)

    Mohamed, Mansour H [Raleigh, NC

    2008-05-27

    A wind blade spar cap for strengthening a wind blade including an integral, unitary three-dimensional woven material having a first end and a second end, corresponding to a root end of the blade and a tip end of the blade, wherein the material tapers in width from the first to the second end while maintaining a constant thickness and decreasing weight therebetween, the cap being capable of being affixed to the blade for providing increased strength with controlled variation in weight from the root end to the tip end based upon the tapered width of the material thereof. The present inventions also include the method of making the wind blade spar cap and a wind blade including the wind blade spar cap.

  5. Repairing methods of steam turbine blades using welding procedures

    International Nuclear Information System (INIS)

    Mazur, Z.; Cristalinas, V.; Kubiak, J.

    1995-01-01

    The steam turbine blades are subjected to the natural permanent wear or damage, which may be of mechanical or metallurgical origin. The typical damage occurring during the lifetime of turbine blading may be erosion, corrosion, foreign objects damage, rubbing and cracking caused by high cycle fatigue and creep crack growth. The nozzle and diaphragm vanes (stationary blades) of the steam turbine are elements whose damage is commonly occurring and they require special repair processes. The damage of the blade trailing edge of nozzle and diaphragm vanes, due to the former causes, may be refurbished by welding deposits or stainless steel inserts welded to the blades. Both repair methods of the stationary steam turbine blades are presented. The results of the blades refurbishment are an increase of the turbine availability, reliability and efficiency, and a decrease of the risk that failure will occur. Also, the repair cost versus the spare blades cost represent significant reduction of expenditure. 7 refs

  6. 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

  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. Designing for hot-blade cutting

    DEFF Research Database (Denmark)

    Brander, David; Bærentzen, Jakob Andreas; Clausen, Kenn

    2016-01-01

    In this paper we present a novel method for the generation of doubly-curved, architectural design surfaces using swept Euler elastica and cubic splines. The method enables a direct design to production workflow with robotic hot-blade cutting, a novel robotic fabrication method under development......-trivial constraints of blade-cutting in a bottom-up fashion, enabling an exploration of the unique architectural potential of this fabrication approach. The method is implemented as prototype design tools in MatLAB, C++, GhPython, and Python and demonstrated through cutting of expanded polystyrene foam design...

  9. Aerodynamics and Optimal Design of Biplane Wind Turbine Blades

    Science.gov (United States)

    Chiu, Phillip

    In order to improve energy capture and reduce the cost of wind energy, in the past few decades wind turbines have grown significantly larger. As their blades get longer, the design of the inboard region (near the blade root) becomes a trade-off between competing structural and aerodynamic requirements. State-of-the-art blades require thick airfoils near the root to efficiently support large loads inboard, but those thick airfoils have inherently poor aerodynamic performance. New designs are required to circumvent this design compromise. One such design is the "biplane blade", in which the thick airfoils in the inboard region are replaced with thinner airfoils in a biplane configuration. This design was shown previously to have significantly increased structural performance over conventional blades. In addition, the biplane airfoils can provide increased lift and aerodynamic efficiency compared to thick monoplane inboard airfoils, indicating a potential for increased power extraction. This work investigates the fundamental aerodynamic aspects, aerodynamic design and performance, and optimal structural design of the biplane blade. First, the two-dimensional aerodynamics of biplanes with relatively thick airfoils are investigated, showing unique phenomena which arise as a result of airfoil thickness. Next, the aerodynamic design of the full biplane blade is considered. Two biplane blades are designed for optimal aerodynamic loading, and their aerodynamic performance quantified. Considering blades with practical chord distributions and including the drag of the mid-blade joint, it is shown that biplane blades have comparable power output to conventional monoplane designs. The results of this analysis also show that the biplane blades can be designed with significantly less chord than conventional designs, a characteristic which enables larger blade designs. The aerodynamic loads on the biplane blades are shown to be increased in gust conditions and decreased under

  10. BLADE acquisition method improves T2-weighted MR images of the female pelvis compared with a standard fast spin-echo sequence

    International Nuclear Information System (INIS)

    Fujimoto, Koji; Koyama, Takashi; Tamai, Ken; Morisawa, Nobuko; Okada, Tomohisa; Togashi, Kaori

    2011-01-01

    Purpose: To investigate feasibility of the periodically rotated overlapping parallel lines with enhanced reconstruction (PROPELLER or BLADE) T2-weighted imaging (T2WI) of the female pelvis by comparing it with standard fast spin-echo T2WI (STD-T2WI). Materials and methods: Sagittal STD-T2WI and BLADE-T2WI of the female pelvis were performed with (36 patients) or without (15 patients) administration of butylscopolamine on a 1.5 T MR unit. Two radiologists independently rated depiction of the uterus, ovary, intestines, bladder, gynecological lesions, overall quality, and artifacts using a four-point scale. Results were compared between STD-T2WI vs. BLADE-T2WI either with (B+) or without (B−) administration of butylscopolamine, BLADE-T2WI (B−) vs. BLADE-T2WI (B+), and STD-T2WI (B+) vs. BLADE-T2WI (B−). Results: When butylscopolamine was administrated, depiction of the uterus, ovary, intestines, gynecological lesions, and overall image quality was rated higher and artifacts were rated fewer for BLADE-T2WI with significance compared with STD-T2WI. When the drug was not administrated, significant difference was observed in depiction of the lesion, overall quality, and artifacts. Depiction of the uterus, gynecological lesion, and overall quality was rated significantly higher and artifacts were fewer in BLADE-T2WI (B+) than in BLADE-T2WI (B−). Conclusion: BLADE method was feasible for female pelvic MRI, with best image quality in BLADE-T2WI (B+).

  11. Modeling the Elastic and Damping Properties of the Multilayered Torsion Bar-Blade Structure of Rotors of Light Helicopters of the New Generation 2. Finite-Element Approximation of Blades and a Model of Coupling of the Torsion Bar with the Blades

    Science.gov (United States)

    Paimushin, V. N.; Shishkin, V. M.

    2016-01-01

    A rod-shape finite element with twelve degrees of freedom is proposed for modeling the elastic and damping properties of rotor blades with regard to their geometric stiffness caused by rotation of the rotor. A model of coupling of the torsion bar with blades is developed based on the hypothesis of linear deplanation of the connecting section of the torsion bar and a special transition element to ensure the compatibility of displacements of the torsion bar and blades upon their vibrations in the flapping and rotation planes. Numerical experiments were carried out to test and assess the validity of the model developed. Suggestions are made for ensuring unconditional stability of the iteration method in a subspace in determining the specified number of modes and frequencies of free vibrations of the torsion bar-blade structure.

  12. Investigation of the effect of bending twisting coupling on the loads in wind turbines with superelement blade definition

    International Nuclear Information System (INIS)

    Gözcü, M O; Kayran, A

    2014-01-01

    Bending-twisting coupling in the composite blades is exploited for load alleviation in the whole turbine system. For the purpose of the study, inverse design of a reference blade is performed such that sectional beam properties of the 3D blade design approximately match the sectional beam properties of NREL's 5MW turbine blade. In order to appropriately account for the bending-twisting coupling effect, dynamic superelement of the blade is created and introduced into the multi-body dynamic model of the wind turbine system. Initially, a comparative study is conducted on the performance of wind turbines which have blades defined as superelements and geometrically nonlinear beams, and conclusions are inferred with regard to the appropriateness of the use of superelement blade definition in the transient analysis of the 5MW wind turbine system that is set up in the present study. Multi-body dynamic simulations of the wind turbine system are performed for the power production load case with the constant wind and the normal turbulence model as external wind loadings. For the internal loads, fatigue damage equivalent load is used as the metric to assess the effect of bending-twisting coupling on the load alleviation in the whole wind turbine system. Results show that in the overall, through the bending-twisting coupling induced with the use of off-axis plies in the main spar caps of the blade, damage equivalent loads associated with the critical load components can be reduced in the wind turbine system

  13. Vibration analysis of gas turbine blade using FEM

    International Nuclear Information System (INIS)

    Iqbal, M.J.; Chohan, G.Y.; Khusnood, S.; Khan, M.A.

    2003-01-01

    In a typical turbo-machine, there is a stator row of blades, which guide the gases onto a rotor row of blades, to extract the mechanical power from the machine. A typical rotor blade was sees upstream disturbance from the stator row and as it rotates, receive a corresponding number of increasing and decreasing lift and moment forces alternating periodically, depending on the number of stator blades/nozzles/guide vanes. Thus all the blades in a turbo-machine receiver their major periodic excitation at a frequency equal to nozzle passing frequency. Since these forces are periodic, one has to consider several number of these harmonics in determining whether resonance takes place, when one of these harmonics coincides with any of the natural frequencies of the blades. Turbine blades have a variety of natural modes of vibration, predominantly as blade alone but also in combination with flexing of the disc rim. These mode occur at characteristic frequencies, which are determined by the distribution of mass and stiffness (in bending or torsion), resulting from the variable thickness over the blade area. Since the advent of steam turbines and their application in various sectors of industry, it is a common experience that a blade failure is a major cause of breakdown in these machines. Blade failures due to fatigue are predominantly vibration related. The dynamic loads on the blading can arise from many sources, the predominant being the source of the operation principles on which the machine is designed. This work deals with vibration analysis of a gas turbine blade using a finite element package ANSYS. Determined the natural frequencies and mode shapes for a turbine blade and a rectangular blade. Results have been validated experimentally using a rectangular blade. ANSYS results have also been compared against published results. (author)

  14. 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....

  15. Digital radiographic technology; non-destructive testing of tubine blades

    NARCIS (Netherlands)

    Penumadu, P.S.

    2014-01-01

    Inspection of turbine blades has always been a big challenge. Any irregularities in the blade have a huge impact on the gas turbine, so these blades have to be manufactured and inspected in the most sophisticated way possible. The evolution of digital radiographic technology took a leap forward to

  16. Antenna Gain Impact on UWB Wind Turbine Blade Deflection Sensing

    DEFF Research Database (Denmark)

    Zhang, Shuai; Franek, Ondrej; Byskov, Claus

    2018-01-01

    Antenna gain impact on UWB wind turbine blade deflection sensing is studied in this paper. Simulations are applied with a 4.5-meter blade tip. The antennas with high gain (HG) and low gain (LG) in free space are simulated inside a blade. It is interesting to find that tip antennas with HG and LG...

  17. Modeling of uncertainties for wind turbine blade design

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Toft, Henrik Stensgaard

    2014-01-01

    Wind turbine blades are designed by a combination of tests and numerical calculations using finite element models of the blade. The blades are typically composite structures with laminates of glass-fiber and/or carbon-fibers glued together by a matrix material. This paper presents a framework...

  18. Gas turbine engine turbine blade damaging estimate in maintenance

    Directory of Open Access Journals (Sweden)

    Ель-Хожайрі Хусейн

    2004-01-01

    Full Text Available  The factors determining character and intensity of corrosive damages of gas turbine blades are analyzed in the article. The classification of detrimental impurities polluting gas turbine airflow duct and injuring blade erosion damages are given. Common features of the method of turbine blade corrosive damage estimation are shown in the article.

  19. Multidisciplinary design optimization of film-cooled gas turbine blades

    Directory of Open Access Journals (Sweden)

    Talya Shashishekara S.

    1999-01-01

    Full Text Available Design optimization of a gas turbine blade geometry for effective film cooling toreduce the blade temperature has been done using a multiobjective optimization formulation. Three optimization formulations have been used. In the first, the average blade temperature is chosen as the objective function to be minimized. An upper bound constraint has been imposed on the maximum blade temperature. In the second, the maximum blade temperature is chosen as the objective function to be minimized with an upper bound constraint on the average blade temperature. In the third formulation, the blade average and maximum temperatures are chosen as objective functions. Shape optimization is performed using geometric parameters associated with film cooling and blade external shape. A quasi-three-dimensional Navier–Stokes solver for turbomachinery flows is used to solve for the flow field external to the blade with appropriate modifications to incorporate the effect of film cooling. The heat transfer analysis for temperature distribution within the blade is performed by solving the heat diffusion equation using the finite element method. The multiobjective Kreisselmeier–Steinhauser function approach has been used in conjunction with an approximate analysis technique for optimization. The results obtained using both formulations are compared with reference geometry. All three formulations yield significant reductions in blade temperature with the multiobjective formulation yielding largest reduction in blade temperature.

  20. Channel flow analysis. [velocity distribution throughout blade flow field

    Science.gov (United States)

    Katsanis, T.

    1973-01-01

    The design of a proper blade profile requires calculation of the blade row flow field in order to determine the velocities on the blade surfaces. An analysis theory is presented for several methods used for this calculation and associated computer programs that were developed are discussed.

  1. A deflection monitoring system for a wind turbine blade

    DEFF Research Database (Denmark)

    2017-01-01

    A wind turbine blade comprising a system for monitoring the deflection of a wind turbine blade is described. The system comprises a wireless range-measurement system, having at least one wireless communication device located towards the root end of the blade and at least one wireless communication...

  2. Design and fabrication of a wind turbine blade | Laryea | Ghana ...

    African Journals Online (AJOL)

    Dimensions and weights were measured to determine the possibilities of its performance. Factors that affect the spinning of the blade include the weight, blade count and its aerodynamic features. The new blades are assumed to be more reliable and efficient than wholly wood design. The calculated wind speed and power ...

  3. Nonlinear analysis of composite thin-walled helicopter blades

    Science.gov (United States)

    Kalfon, J. P.; Rand, O.

    Nonlinear theoretical modeling of laminated thin-walled composite helicopter rotor blades is presented. The derivation is based on nonlinear geometry with a detailed treatment of the body loads in the axial direction which are induced by the rotation. While the in-plane warping is neglected, a three-dimensional generic out-of-plane warping distribution is included. The formulation may also handle varying thicknesses and mass distribution along the cross-sectional walls. The problem is solved by successive iterations in which a system of equations is constructed and solved for each cross-section. In this method, the differential equations in the spanwise directions are formulated and solved using a finite-differences scheme which allows simple adaptation of the spanwise discretization mesh during iterations.

  4. Effect of linear and non-linear blade modelling techniques on simulated fatigue and extreme loads using Bladed

    Science.gov (United States)

    Beardsell, Alec; Collier, William; Han, Tao

    2016-09-01

    There is a trend in the wind industry towards ever larger and more flexible turbine blades. Blade tip deflections in modern blades now commonly exceed 10% of blade length. Historically, the dynamic response of wind turbine blades has been analysed using linear models of blade deflection which include the assumption of small deflections. For modern flexible blades, this assumption is becoming less valid. In order to continue to simulate dynamic turbine performance accurately, routine use of non-linear models of blade deflection may be required. This can be achieved by representing the blade as a connected series of individual flexible linear bodies - referred to in this paper as the multi-part approach. In this paper, Bladed is used to compare load predictions using single-part and multi-part blade models for several turbines. The study examines the impact on fatigue and extreme loads and blade deflection through reduced sets of load calculations based on IEC 61400-1 ed. 3. Damage equivalent load changes of up to 16% and extreme load changes of up to 29% are observed at some turbine load locations. It is found that there is no general pattern in the loading differences observed between single-part and multi-part blade models. Rather, changes in fatigue and extreme loads with a multi-part blade model depend on the characteristics of the individual turbine and blade. Key underlying causes of damage equivalent load change are identified as differences in edgewise- torsional coupling between the multi-part and single-part models, and increased edgewise rotor mode damping in the multi-part model. Similarly, a causal link is identified between torsional blade dynamics and changes in ultimate load results.

  5. Structural experiment of wind turbine blades; Fushayo blade no zairyo rikigakuteki jikken kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Seki, K; Shimizu, Y; Kuroyanagi, H [Tokai University, Tokyo (Japan)

    1997-11-25

    Aluminum, GFRP and composite of aluminum coated with carbon as structural materials for wind turbine blades were bending-tested, to improve blade bending stiffness, understand stress conditions at each position, and clarify structural dynamic strength by the bending-failure test. It is possible to estimate stress conditions at each position from the test results of displacement and strain at each load. The test results with GFRP are well explained qualitatively by the boundary theory, known as a theory for composite materials. The test gives reasonable material strength data, useful for designing wind turbines of high functions and safety. The results of the blade bending-failure test are in good agreement with the calculated structural blade strength. It is also found that GFRP is a good material of high structural strength for wind turbines. 8 refs., 6 tabs.

  6. [Cross sectional study of structural quality of German intensive care units. A reevaluation of the DIVI register].

    Science.gov (United States)

    Fölsch, C; Kofahl, N; Waydhas, C; Stiletto, R

    2013-09-01

    Effectiveness of intensive care treatment is essential to cope with increasing costs. The German national register of intensive care established by the German Interdisciplinary Association for Intensive Care Medicine (DIVI) contains basic data on the structure of intensive care units in Germany. A repeat analysis of data of the DIVI register within 8 years provides information for the development of intensive care units under different economic circumstances. The recent data on the structure of intensive care units were obtained in 2008 and compared with the primary multicenter study from 2000. The hospitals selected were a representative sample for the whole of Germany. Data on the status of the hospital, staff and technical facilities, foundation of the hospital and the statistics of mechanically ventilated patients were analyzed. The technical facilities and the number of staff have improved from 2000 to 2008. A smaller availability of diagnostic procedures and staff remain in hospitals for basic treatment outside normal working hours. The average utilization of intensive care unit beds was not altered. The existence of intermediate care units did not significantly change the proportion of patients with artificial ventilation or ventilation times. The number of beds in intensive care units was unchanged as was the average number of beds in units and the number of patients treated. A relevant number of beds of intensive care units shifted towards hospitals with private foundation without changes in the overall numbers. The structure of the hospitals was comparable at both time points. The introduction of intermediate care units did not alter ventilation parameters of patients in 2008 compared with 2000. There is no obvious medical reason for the shift of intensive care beds towards private hospitals. The number of staff and patients varied considerably between the intensive care units. The average number of patients treated per bed was not different between the

  7. Doctor Blade-Coated Polymer Solar Cells

    KAUST Repository

    Cho, Nam Chul; Kim, Jong H.

    2016-01-01

    In this work, we report polymer solar cells based on blade-coated P3HT:PC71BM and PBDTTT-EFT:PC71BM bulk heterojunction photoactive layers. Enhanced power conversion efficiency of 2.75 (conventional structure) and 3.03% (inverted structure

  8. A Two-Bladed Concept Wind Turbine

    DEFF Research Database (Denmark)

    Kim, Taeseong

    2012-01-01

    This article shows the potential for reducing extreme loads with an innovative design of wind turbine, a partial pitch two-bladed concept turbine. The most extreme conditions to test a turbine are considered to be stand-still combined with a grid failure in which the wind comes from all directions...

  9. Fatigue Life of Wind Turbine Blades

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    2010-01-01

    The present paper analyses the possibility of reducing the expected damage accumulation during tower passage by modifying the wind turbine tower design from a traditional mono-tower to a tripod. Due to a narrow stagnation zone the stress reversals and hence the damage accumulation in the blades...

  10. Gas Turbine Blade Damper Optimization Methodology

    Directory of Open Access Journals (Sweden)

    R. K. Giridhar

    2012-01-01

    Full Text Available The friction damping concept is widely used to reduce resonance stresses in gas turbines. A friction damper has been designed for high pressure turbine stage of a turbojet engine. The objective of this work is to find out effectiveness of the damper while minimizing resonant stresses for sixth and ninth engine order excitation of first flexure mode. This paper presents a methodology that combines three essential phases of friction damping optimization in turbo-machinery. The first phase is to develop an analytical model of blade damper system. The second phase is experimentation and model tuning necessary for response studies while the third phase is evaluating damper performance. The reduced model of blade is developed corresponding to the mode under investigation incorporating the friction damper then the simulations were carried out to arrive at an optimum design point of the damper. Bench tests were carried out in two phases. Phase-1 deals with characterization of the blade dynamically and the phase-2 deals with finding optimal normal load at which the blade resonating response is minimal for a given excitation. The test results are discussed, and are corroborated with simulated results, are in good agreement.

  11. Hot Blade Cuttings for the Building Industries

    DEFF Research Database (Denmark)

    Brander, David; Bærentzen, Jakob Andreas; Evgrafov, Anton

    2016-01-01

    . The project aims to reduce the amount of manual labour as well as production time by applying robots to cut expanded polystyrene (EPS) moulds for the concrete to form doubly curved surfaces. The scheme is based upon the so-called Hot Wire or Hot Blade technology where the surfaces are essentially swept out...

  12. Remote inspection of steam turbine blades

    International Nuclear Information System (INIS)

    Anon.

    1987-01-01

    During the past five years Reinhart and Associates, Inc. has been involved in remote examination of L-0 and L-1 steam turbine blade rows of in-place LP turbines using visual and eddy current techniques. These tests have concentrated on the trailing edge and blade-to-rotor attachment (Christmas tree) areas. These remote nondestructive examinations were performed through hand access ports of the inner shell. Since the remote scanning system was in a prototype configuration, the inspection was highly operator-dependent. Refinement of the scanning equipment would considerably improve the efficiency of the test; however, the feasibility of remote in-place inspection of turbine blades was established. To further improve this technology, and to provide for remote inspection of other areas of the blade and additional turbine designs, EPRI is funding a one-year project with Reinhart and Associates, Inc. This project will develop a new system that employs state-of-the-art multifrequency eddy current techniques, a miniature charged coupled device (CCD) television camera, and remote positioning equipment. Project results from the first six months are presented

  13. Fluidic load control for wind turbines blades

    NARCIS (Netherlands)

    Boeije, C.S.; Vries, de H.; Cleine, I.; Emden, van E.; Zwart, G.G.M.; Stobbe, H.; Hirschberg, A.; Hoeijmakers, H.W.M.; Maureen Hand, xx

    2009-01-01

    This paper describes the initial steps into the investigation of the possibility of reducing fatigue loads on wind turbine blades by the application of fluidic jets. This investigation involves static pressure measurements as well as numerical simulations for a non-rotating NACA-0018 airfoil. The

  14. Structural dynamic analysis of turbine blade

    Science.gov (United States)

    Antony, A. Daniel; Gopalsamy, M.; Viswanadh, Chaparala B. V.; Krishnaraj, R.

    2017-10-01

    In any gas turbine design cycle, blade design is a crucial element which needs maximum attention to meet the aerodynamic performance, structural safety margins, manufacturing feasibility, material availability etc. In present day gas turbine engines, most of the failures occur during engine development test and in-service, in rotor and stator blades due to fatigue and resonance failures. To address this issue, an extensive structural dynamic analysis is carried out to predict the natural frequencies and mode shapes using FE methods. Using the dynamics characteristics, the Campbell diagram is constructed to study the possibility of resonance at various operating speeds. In this work, the feasibility of using composite material in place of titanium alloy from the structural dynamics point of view. This is being attempted in a Low-pressure compressor where the temperatures are relatively low and fixed with the casings. The analysis will be carried out using FE method for different composite material with different lamina orientations chosen through the survey. This study will focus on the sensitivity of blade mode shapes to different laminae orientations, which will be used to alter the natural frequency and tailor the mode shapes. Campbell diagrams of existing titanium alloy are compared with the composite materials with different laminae at all critical operating conditions. The existing manufacturing methods and the proven techniques for blade profiles will also be discussed in this report.

  15. Torsional Performance of Wind Turbine Blades

    DEFF Research Database (Denmark)

    Branner, Kim; Berring, Peter; Berggreen, Christian

    2007-01-01

    The present work investigates how well different finite element modeling techniques can predict bending and torsion behavior of a wind turbine blade. Two shell models are investigated. One model has element offsets and the other has the elements at the mid-thickness surfaces of the model. The las...

  16. The Evolution of Rotor and Blade Design

    Energy Technology Data Exchange (ETDEWEB)

    Tangler, J.

    2000-08-01

    The objective of this paper is to provide a historical perspective of the evolution of rotor and blade design during the last 20 years. This evolution is a balanced integration of economic, aerodynamic, structural dynamic, noise, and aesthetic considerations, which are known to be machine type and size dependent.

  17. Mathematical Model of Two Blades System

    Czech Academy of Sciences Publication Activity Database

    Půst, Ladislav; Pešek, Luděk

    2014-01-01

    Roč. 2, č. 4 (2014), s. 361-369 ISSN 2321-3558 R&D Projects: GA ČR GA101/09/1166 Institutional support: RVO:61388998 Keywords : turbine blades * dry friction * vibration damping * torsion Subject RIV: BI - Acoustics

  18. KNOW-BLADE task-4 report. Navier-Stokes aeroelasticity

    Energy Technology Data Exchange (ETDEWEB)

    Politis, E.S.; Nikolaou, I.G.; Chaviaropoulos, P.K.; Bertagnolio, F.; Soerensen, N.N.; Johansen, J.

    2005-01-01

    The problem of the aeroelastic stability of wind turbine blades is addressed in this report by advancing the aerodynamic modelling in the beam element type codes from the engineering-type empirical models to unsteady, 2D or 3D, Navier-Stokes solvers. In this project, structural models for the full wind turbine blade have been combined with 2D and 3D unsteady Navier-Stokes solvers. The relative disadvantage of the quasi-3D approach (where the elastic solver is coupled with a 2D Navier-Stokes solver) is its inability to model induced flow. The lack of a validation test case did not allow for quantitative comparisons with experimental data to be carried out; instead the results of the advanced aeroelastic tools are qualitatively cross-compared. All investigated methods predicted qualitatively similar results. They all resulted in positive aerodynamic damping values for the flap mode, in a decrease in damping with the increase of wind speeds and in a minimum value for the damping for wind speed around 15{approx}m/s. The eigenvalue analyses resulted in steeper distributions for this mode. The agreement in aerodynamic damping decrease with the increase of wind speed is also observed in the distributions for the lead-lag mode. In perspective, the uncoupled, linear method results in higher values of aerodynamic damping compared to the 3D aeroelastic tool. The quasi-3D tool results in lower aerodynamic damping values in the higher wind speeds and in lower damping values in the lower wind speed regime. Apart from the computations for the full blade, 2D computations for the so-called 'typical section' have been carried out. The 2D aeroelastic tools resulted in similar aerodynamic damping values. Qualitative agreement was better for the lead-lag mode. The presence of roughness tapes has a small, rather negligible impact on aeroelastic stability as depicted by the results of both aeroelastic tools. On the other hand, in conformity to the inability of the adopted

  19. Repair welding of cracked steam turbine blades

    International Nuclear Information System (INIS)

    Bhaduri, A.K.; Gill, T.P.S.; Albert, S.K.; Shanmugam, K.; Iyer, D.R.

    1999-01-01

    The procedure for repair welding of cracked steam turbine blades made of martensitic stainless steels has been developed using the gas tungsten arc welding process. Weld repair procedures were developed using both ER316L austenitic stainless steel filler wire and ER410 martensitic stainless steel filler wire. The repair welding procedure with austenitic filler wire was developed to avoid preheating of the blade as also hydrogen induced cold cracking, and involved evaluation of three different austenitic filler wires, viz. ER309L, ER316L and ERNiCr-3. The overall development of the repair welding procedure included selection of welding consumables (for austenitic filler metal), optimisation of post weld heat treatment parameters, selection of suitable method for local pre-heating and post-weld heat treatment (PWHT) of the blades, determination of mechanical properties of weldments in as-welded and PWHT conditions, and microstructural examination. After various trials using different procedures, the procedure of local PWHT using electrical resistance heating on the top surface of the weldment and monitoring the temperature by placing a thermocouple at the bottom of the weld, was found to give the most satisfactory results. A similar procedure was used for preheating while using ER410 filler metal. Mechanical testing of weldments before and after PWHT involved tensile tests at room temperature, face and root bend tests, and microhardness measurements across the fusion line and heat affected zone. During procedure qualification, mock-ups and actual repair welding, dye penetrant testing was used at different stages and where ever possible radiography was carried out. These procedures were developed for repair welding of cracked blades in the low-pressure (LP) steam turbines of Indian nuclear power plants. The procedure with ER316 L filler wire has so far been applied for repair welding of 2 cracked blades (made of AISI 410 SS) of LP steam turbines, while the procedure

  20. Comparison of intensive care unit medication errors reported to the United States' MedMarx and the United Kingdom's National Reporting and Learning System: a cross-sectional study.

    Science.gov (United States)

    Wahr, Joyce A; Shore, Andrew D; Harris, Lindsay H; Rogers, Philippa; Panesar, Sukhmeet; Matthew, Linda; Pronovost, Peter J; Cleary, Kevin; Pham, Julius C

    2014-01-01

    The objective was to compare the characteristics of medication errors reported to 2 national error reporting systems by conducting a cross-sectional analysis of errors reported from adult intensive care units to the UK National Reporting and Learning System and the US MedMarx system. Outcome measures were error types, severity of patient harm, stage of medication process, and involved medications. The authors analyzed 2837 UK error reports and 56 368 US reports. Differences were observed between UK and US errors for wrong dose (44% vs 29%), omitted dose (8.6% vs 27%), and stage of medication process (prescribing: 14% vs 49%; administration: 71% vs 42%). Moderate/severe harm or death was reported in 4.9% of UK versus 3.4% of US errors. Gentamicin was cited in 7.4% of the UK versus 0.7% of the US reports (odds ratio = 9.25). There were differences in the types of errors reported and the medications most often involved. These differences warrant further examination.

  1. Analysis of impact resistance of composite fan blade. Fukugozai fan blade no taishogekisei no kaiseki

    Energy Technology Data Exchange (ETDEWEB)

    Miyachi, T; Okumura, H; Otake, K; Sofue, Y [Japan Society for Aeronautical and Space Sciences, Tokyo (Japan)

    1992-01-05

    Numerical analysis of impact response was carried out when a bird strike was simulated to study the applicability of fiber reinforced composite material to fan blades for turbo-fan engines. The validity of the numerical analysis was verified by comparing the analyzed results with impact tested results of a fan-blade model of Ti-alloy. The impact resistance was studied by applying this method to fan blades of composite materials such as carbon fiber, epoxy resin and carbon-silicate fiber reinforced Ti-alloy. The finite element method was used for the analysis by dividing the model into triangular flat elements. The relation between the impact load, the deformation of blade and the strain, the natural frequency characteristics, the elastic modulus and hetrogeneity of blade were considered to analyze the impact response. The impact load by the strike of 1.5 lbs bird is very severe to the fan blades for turbo-fan engines having the thrust of 5 ton class. 23 refs., 23 figs., 3 tabs.

  2. Load alleviation on wind turbine blades using variable airfoil geometry

    Energy Technology Data Exchange (ETDEWEB)

    Basualdo, S.

    2005-03-01

    A two-dimensional theoretical study of the aeroelastic behaviour of an airfoil has been performed, whose geometry can be altered using a rear-mounted flap. This device is governed by a controller, whose objective is to reduce the airfoil displacements and, therefore, the stresses present in a real blade. The aerodynamic problem was solved numerically by a panel method using the potential theory, suitable for modelling attached flows. It is therefore mostly applicable for Pitch Regulated Variable Speed (PRVS) wind turbines, which mainly operate under this flow condition. The results show evident reductions in the airfoil displacements by using simple control strategies having the airfoil position and its first and second derivatives as input, especially at the system's eigenfrequency. The use of variable airfoil geometry is an effective means of reducing the vibration magnitudes of an airfoil that represents a section of a wind turbine blade, when subject to stochastic wind signals. The results of this investigation encourage further investigations with 3D aeroelastic models to predict the reduction in loads in real wind turbines. (author)

  3. Prospects for the domestic production of large-sized cast blades and vanes for industrial gas turbines

    Science.gov (United States)

    Kazanskiy, D. A.; Grin, E. A.; Klimov, A. N.; Berestevich, A. I.

    2017-10-01

    Russian experience in the production of large-sized cast blades and vanes for industrial gas turbines is analyzed for the past decades. It is noted that the production of small- and medium-sized blades and vanes made of Russian alloys using technologies for aviation, marine, and gas-pumping turbines cannot be scaled for industrial gas turbines. It is shown that, in order to provide manufacturability under large-scale casting from domestic nickel alloys, it is necessary to solve complex problems in changing their chemical composition, to develop new casting technologies and to optimize the heat treatment modes. An experience of PAO NPO Saturn in manufacturing the blades and vanes made of ChS88U-VI and IN738-LC foundry nickel alloys for the turbines of the GTE-110 gas turbine unit is considered in detail. Potentialities for achieving adopted target parameters for the mechanical properties of working blades cast from ChS88UM-VI modified alloy are established. For the blades made of IN738-LC alloy manufactured using the existing foundry technology, a complete compliance with the requirements of normative and technical documentation has been established. Currently, in Russia, the basis of the fleet of gas turbine plants is composed by foreign turbines, and, for the implementation of the import substitution program, one can use the positive experience of PAO NPO Saturn in casting blades from IN738-LC alloy based on a reverse engineering technique. A preliminary complex of studies of the original manufacturer's blades should be carried out, involving, first of all, the determination of geometric size using modern measurement methods as well as the studies on the chemical compositions of the used materials (base metal and protective coatings). Further, verifying the constructed calculation models based on the obtained data, one could choose available domestic materials that would meet the operating conditions of the blades according to their heat resistance and corrosion

  4. Dynamic stress of impeller blade of shaft extension tubular pump device based on bidirectional fluid-structure interaction

    Energy Technology Data Exchange (ETDEWEB)

    Kan, Kan; Liu, Huiwen; Yang, Chunxia [Hohai University, Nanjing (China); Zheng, Yuan [National Engineering Research Center of Water Resources Efficient Utilization and Engineering Safety, Nanjing (China); Fu, Shifeng; Zhang, Xin [Power China Huadong Engineering Corporation, Hangzhou (China)

    2017-04-15

    Current research on the stability of tubular pumps is mainly concerned with the transient hydrodynamic characteristics. However, the structural response under the influence of fluid-structure interaction hasn't been taken fully into consideration. The instability of the structure can cause vibration and cracks, which may threaten the safety of the unit. We used bidirectional fluid-structure interaction to comprehensively analyze the dynamic stress characteristics of the impeller blades of the shaft extension tubular pump device. Furthermore, dynamic stress of impeller blade of shaft extension tubular pump device was solved under different lift conditions of 0° blade angle. Based on Reynolds-average N-S equation and SST k-ω turbulence model, numerical simulation was carried out for three-dimensional unsteady incompressible turbulent flow field of the pump device whole flow passage. Meanwhile, the finite element method was used to calculate dynamic characteristics of the blade structure. The blade dynamic stress distribution was obtained on the basis of fourth strength theory. The research results indicate that the maximum blade dynamic stress appears at the joint between root of inlet side of the blade suction surface and the axis. Considering the influence of gravity, the fluctuation of the blade dynamic stress increases initially and decreases afterwards within a rotation period. In the meantime, the dynamic stress in the middle part of inlet edge presents larger relative fluctuation amplitude. Finally, a prediction method for dynamic stress distribution of tubular pump considering fluid-structure interaction and gravity effect was proposed. This method can be used in the design stage of tubular pump to predict dynamic stress distribution of the structure under different operating conditions, improve the reliability of pump impeller and analyze the impeller fatigue life.

  5. Analysis and improvement of gas turbine blade temperature measurement error

    International Nuclear Information System (INIS)

    Gao, Shan; Wang, Lixin; Feng, Chi; Daniel, Ketui

    2015-01-01

    Gas turbine blade components are easily damaged; they also operate in harsh high-temperature, high-pressure environments over extended durations. Therefore, ensuring that the blade temperature remains within the design limits is very important. In this study, measurement errors in turbine blade temperatures were analyzed, taking into account detector lens contamination, the reflection of environmental energy from the target surface, the effects of the combustion gas, and the emissivity of the blade surface. In this paper, each of the above sources of measurement error is discussed, and an iterative computing method for calculating blade temperature is proposed. (paper)

  6. Analysis and improvement of gas turbine blade temperature measurement error

    Science.gov (United States)

    Gao, Shan; Wang, Lixin; Feng, Chi; Daniel, Ketui

    2015-10-01

    Gas turbine blade components are easily damaged; they also operate in harsh high-temperature, high-pressure environments over extended durations. Therefore, ensuring that the blade temperature remains within the design limits is very important. In this study, measurement errors in turbine blade temperatures were analyzed, taking into account detector lens contamination, the reflection of environmental energy from the target surface, the effects of the combustion gas, and the emissivity of the blade surface. In this paper, each of the above sources of measurement error is discussed, and an iterative computing method for calculating blade temperature is proposed.

  7. 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.

  8. CFD simulation of crossflow mixing in a rod bundle with mixing blades

    International Nuclear Information System (INIS)

    In, W. K.

    1999-01-01

    A CFD model was developed in this study to simulate the crossflow mixing in a 4x4 square array rod bundle caused by ripped-open blades. The central subchannel and adjacent subchannels of one grid span were modeled using flow symmetry. The lateral velocity pattern within the central subchannel, lateral velocity and the turbulence intensity in the rod gap region were predicted by the CFD method, and the predictions were compared with the measurements. The CFD simulation shows a vortex flow around the fuel rod caused by a pair of blades, which is consistent with the experimental results. The CFD predictions of the lateral velocity on the mixing sections show a near symmetric profile, but the measurements present an asymmetric velocity profile leading to an inversion of lateral velocity. The predicted mixing rate between the central subchannel and the adjacent subchannels reasonably agrees with the measured one. The CFD prediction shows a parabolic distribution of the RMS velocity but the measured one shows a rather flat distribution near the blade that develops to a parabolic distribution far downstream (L=29De). The predicted average RMS velocity on a mixing section is also slightly lower than the measured one. This study confirmed that the CFD simulation can present the effect of the ripped-open blades on the crossflow mixing in a rod bundle well

  9. Structural and mechanism design of an active trailing-edge flap blade

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jae Hwan [Samsung Techwin R and D Center, Seongnam (Korea, Republic of); Natarajan, Balakumaran; Eun, Won Jong; Shin, Sang Joon [Seoul National University, Seoul (Korea, Republic of); R, Viswamurthy S. [National Aerospace Laboratories, Bangalore (India); Park, Jae Sang [Agency for Defense Development, Daejeon (Korea, Republic of); Kim, Tae Song [Technical University of Denmark, Risoe Campus, Roskilde (Denmark)

    2013-09-15

    A conventional rotor control system restricted at 1/rev frequency component is unable to vary the hub vibratory loads and the aero acoustic noise, which exist in high frequency components. Various active rotor control methodologies have been examined in the literature to alleviate the problem of excessive hub vibratory loads and noise. The active control device manipulates the blade pitch angle with arbitrary higher harmonic frequencies individually. In this paper, an active trailing-edge flap blade, which is one of the active control methods, is developed to reduce vibratory loads and noise of the rotor through modification of unsteady aerodynamic loads. Piezoelectric actuators installed inside the blade manipulate the motion of the trailing edge flap. The proposed blade rotates at higher speed and additional structures are included to support the actuators and the flap. This improves the design, as the blade is able to withstand increased centrifugal force. The cross-section of the active blade is designed first. A stress/strain recovery analysis is then conducted to verify its structural integrity. A one-dimensional beam analysis is also carried out to assist with the construction of the fan diagram. To select the actuator and design the flap actuation region, the flap hinge moment is estimated via a CFD analysis. To obtain the desired flap deflection of ±4 .deg. , three actuators are required. The design of the flap actuation region is validated using a test bed with a skin hinge. However, because the skin hinge induces additional flap hinge moment, it does not provide sufficient deflection angle. Therefore, the flap hinge is replaced by a pin-type hinge, and the results are evaluated.

  10. Heat Transfer and Flow on the First Stage Blade Tip of a Power Generation Gas Turbine. Part 1; Experimental Results

    Science.gov (United States)

    Bunker, Ronald S.; Bailey, Jeremy C.; Ameri, Ali A.

    1999-01-01

    A combined computational and experimental study has been performed to investigate the detailed distribution of convective heat transfer coefficients on the first stage blade tip surface for a geometry typical of large power generation turbines(>100MW). This paper is concerned with the design and execution of the experimental portion of the study. A stationary blade cascade experiment has been run consisting of three airfoils, the center airfoil having a variable tip gap clearance. The airfoil models the aerodynamic tip section of a high pressure turbine blade with inlet Mach number of 0.30, exit Mach number of 0.75, pressure ratio of 1.45, exit Reynolds number based on axial chord of 2.57 x 10(exp 6), and total turning of about 110 degrees. A hue detection based liquid crystal method is used to obtain the detailed heat transfer coefficient distribution on the blade tip surface for flat, smooth tip surfaces with both sharp and rounded edges. The cascade inlet turbulence intensity level took on values of either 5% or 9%. The cascade also models the casing recess in the shroud surface ahead of the blade. Experimental results are shown for the pressure distribution measurements on the airfoil near the tip gap, on the blade tip surface, and on the opposite shroud surface. Tip surface heat transfer coefficient distributions are shown for sharp-edge and rounded-edge tip geometries at each of the inlet turbulence intensity levels.

  11. Determination of Turbine Blade Life from Engine Field Data

    Science.gov (United States)

    Zaretsky, Erwin V.; Litt, Jonathan S.; Hendricks, Robert C.; Soditus, Sherry M.

    2013-01-01

    It is probable that no two engine companies determine the life of their engines or their components in the same way or apply the same experience and safety factors to their designs. Knowing the failure mode that is most likely to occur minimizes the amount of uncertainty and simplifies failure and life analysis. Available data regarding failure mode for aircraft engine blades, while favoring low-cycle, thermal-mechanical fatigue (TMF) as the controlling mode of failure, are not definitive. Sixteen high-pressure turbine (HPT) T-1 blade sets were removed from commercial aircraft engines that had been commercially flown by a single airline and inspected for damage. Each set contained 82 blades. The damage was cataloged into three categories related to their mode of failure: (1) TMF, (2) Oxidation/erosion (O/E), and (3) Other. From these field data, the turbine blade life was determined as well as the lives related to individual blade failure modes using Johnson-Weibull analysis. A simplified formula for calculating turbine blade life and reliability was formulated. The L10 blade life was calculated to be 2427 cycles (11 077 hr). The resulting blade life attributed to O/E equaled that attributed to TMF. The category that contributed most to blade failure was Other. If there were no blade failures attributed to O/E and TMF, the overall blade L(sub 10) life would increase approximately 11 to 17 percent.

  12. Development of 52 inch last stage blade for steam turbine

    International Nuclear Information System (INIS)

    Kadoya, Yoshiki; Harada, Masakatsu; Watanabe, Eiichiro

    1985-01-01

    Mitsubishi Heavy Industries, Ltd. has developed the last stage blades with 1320 mm length for a 1800 rpm LP turbine, and the verification by rotating vibration test using actual blades was finished, thus the blades were completed. In a nuclear power plant with an A-PWR of 3800 MW thermal output, the 1350 MW steam turbine has one HP turbine and three LP turbines coupled in tandem, and the optimum last stage blades for the LP turbines became the 1320 mm blades. The completion of these blades largely contributes to the improvement of thermal efficiency and the increase of generator output in large nuclear power plants, and has the possibility to decrease three LP turbines to two in 900 MW plants, which reduces the construction cost. The velocity energy of steam coming out of last stage blades is abandoned as exhaust loss in a condenser, which is the largest loss in a turbine. The increase of exhaust area using long blades reduces this loss. The economy of the 1320 mm blades, the features of the 1320 mm blades, the aerodynamic design and its verification, the prevention of the erosion of the 1320 mm blades due to wet steam, the strength design, the anti-vibration design and its verification, and the CAD/CAM system are reported. (Kako, I.)

  13. Fundamental investigation on the impact strength of hollow fan blades

    Energy Technology Data Exchange (ETDEWEB)

    Ikeda, T; Miyachi, T; Sofue, Y

    1985-01-01

    Models of hollow fan blades were made and tested to prove that their strength is sufficient for use in real engines. The hollow blades were fabricated by diffusion bonding of two titanium alloy (6Al-4V-Ti) plates, one of which had three spanwise stiffners and the other being flat plate. The model as a nontwisted tapered blade. Impact tests were carried out on the hollow fan blade models in which the ingestion of a 1.5 pounds bird was simulated. Solid blades with the same external form were also tested by similar methods for comparison. The results of these tests show that properly designed hollow blades have sufficient stiffness and strength for use as fan blades in the turbo-fan engine.

  14. Antenna Gain Impact on UWB Wind Turbine Blade Deflection Sensing

    DEFF Research Database (Denmark)

    Zhang, Shuai; Franek, Ondrej; Byskov, Claus

    2018-01-01

    effective (or equivalent) isotropic radiated power (EIRP), an HG tip antenna inside a blade gives stronger direct pulse amplitudes and better pulse waveforms for accurate and reliable distance estimations than the LG. Moreover, the direct pulse with the HG antenna is also closer to the blade surface, which...... in free space have similar realized gain when allocated inside blades, so that the emission power for the HG and LG antennas in blades can be the same. The antenna gain impacts on time-domain pulse waveforms and power distributions around a blade are carefully investigated (with the tip antenna inside...... a blade). Higher antenna gain enlarges both direct pulse and multipath but in different levels. To verify the simulations, time-domain measurements are performed with a full 37-meter blade. Pulse waveforms and power delay profiles are measured. From all the studies, it follows that: with the similar...

  15. Beyond Section 508: The Spectrum of Legal Requirements for Accessible e-Government Web Sites in the United States

    Science.gov (United States)

    Jaeger, Paul T.

    2004-01-01

    In the United States, a number of federal laws establish requirements that electronic government (e-government) information and services be accessible to individuals with disabilities. These laws affect e-government Web sites at the federal, state, and local levels. To this point, research about the accessibility of e-government Web sites has…

  16. Nursing unit teams matter: Impact of unit-level nurse practice environment, nurse work characteristics, and burnout on nurse reported job outcomes, and quality of care, and patient adverse events--a cross-sectional survey.

    Science.gov (United States)

    Van Bogaert, Peter; Timmermans, Olaf; Weeks, Susan Mace; van Heusden, Danny; Wouters, Kristien; Franck, Erik

    2014-08-01

    To investigate the impact of nurse practice environment factors, nurse work characteristics, and burnout on nurse reported job outcomes, quality of care, and patient adverse events variables at the nursing unit level. Nurse practice environment studies show growing insights and knowledge about determining factors for nurse workforce stability, quality of care, and patient safety. Until now, international studies have primarily focused on variability at the hospital level; however, insights at the nursing unit level can reveal key factors in the nurse practice environment. A cross-sectional design with a survey. In a cross-sectional survey, a sample of 1108 nurses assigned to 96 nursing units completed a structured questionnaire composed of various validated instruments measuring nurse practice environment factors, nurse work characteristics, burnout, nurse reported job outcomes, quality of care, and patient adverse events. Associations between the variables were examined using multilevel modelling techniques. Various unit-level associations (simple models) were identified between nurse practice environment factors, nurse work characteristics, burnout dimensions, and nurse reported outcome variables. Multiple multilevel models showed various independent variables such as nursing management at the unit level, social capital, emotional exhaustion, and depersonalization as important predictors of nurse reported outcome variables such job satisfaction, turnover intentions, quality of care (at the unit, the last shift, and in the hospital within the last year), patient and family complaints, patient and family verbal abuse, patient falls, nosocomial infections, and medications errors. Results suggested a stable nurse work force, with the capability to achieve superior quality and patient safety outcomes, is associated with unit-level favourable perceptions of nurse work environment factors, workload, decision latitude, and social capital, as well low levels of burnout

  17. 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.

  18. Assessment and management of pain in newborns hospitalized in a Neonatal Intensive Care Unit: a cross-sectional study.

    Science.gov (United States)

    Sposito, Natália Pinheiro Braga; Rossato, Lisabelle Mariano; Bueno, Mariana; Kimura, Amélia Fumiko; Costa, Taine; Guedes, Danila Maria Batista

    2017-09-12

    to determine the frequency of pain, to verify the measures adopted for pain relief during the first seven days of hospitalization in the Neonatal Intensive Care Unit and to identify the type and frequency of invasive procedures to which newborns are submitted. cross-sectional retrospective study. Out of the 188 hospitalizations occurred during the 12-month period, 171 were included in the study. The data were collected from the charts and the presence of pain was analyzed based on the Neonatal Infant Pain Scale and on nursing notes suggestions of pain. For statistical analysis, the Statistical Package for the Social Sciences was used, and the significance level was set at 5%. there was at least one record of pain in 50.3% of the hospitalizations, according to the pain scale adopted or nursing note. The newborns underwent a mean of 6.6 invasive procedures per day. Only 32.5% of the pain records resulted in the adoption of pharmacological or non-pharmacological intervention for pain relief. newborns are frequently exposed to pain and the low frequency of pharmacological or non-pharmacological interventions reinforces the undertreatment of this condition. determinar a frequência de dor e verificar as medidas realizadas para seu alívio durante os sete primeiros dias de internação na Unidade de Terapia Intensiva Neonatal, bem como identificar o tipo e frequência de procedimentos invasivos aos quais os recém-nascidos foram submetidos. estudo retrospectivo transversal. Das 188 internações ocorridas no período estipulado de 12 meses, 171 foram incluídas na pesquisa. Os dados foram coletados a partir dos prontuários e a presença de dor foi analisada tanto com base na escala de dor Neonatal Infant Pain Scale quanto mediante anotação de enfermagem sugestiva de dor. Para análise estatística, utilizou-se o programa Statistical Package for the Social Sciences, adotando-se nível de significância de 5%. em 50,3% das internações houve ao menos um registro de dor

  19. Wind Turbine Blade Nondestructive Testing with a Transportable Radiography System

    Directory of Open Access Journals (Sweden)

    J. G. Fantidis

    2011-01-01

    Full Text Available Wind turbines are becoming widely used as they are an environmentally friendly way for energy production without emissions; however, they are exposed to a corrosive environment. In addition, as wind turbines typically are the tallest structures in the surrounding area of a wind farm, it is expected that they will attract direct lightning strikes several times during their operating life. The purpose of this paper is to show that the radiography with a transportable unit is a solution to find defects in the wind turbine blade and reduce the cost of inspection. A transportable neutron radiography system, incorporating an Sb–Be source, has been simulated using the MCNPX code. The simulated system has a wide range of radiography parameters.

  20. Deflection estimation of a wind turbine blade using FBG sensors embedded in the blade bonding line

    International Nuclear Information System (INIS)

    Kim, Sang-Woo; Kang, Woo-Ram; Jeong, Min-Soo; Lee, In; Kwon, Il-Bum

    2013-01-01

    Estimating the deflection of flexible composite wind turbine blades is very important to prevent the blades from hitting the tower. Several researchers have used fiber Bragg grating (FBG) sensors—a type of optical fiber sensor (OFS)—to monitor the structural behavior of the blades. They can be installed on the surface and/or embedded in the interior of composites. However, the typical installation positions of OFSs present several problems, including delamination of sensing probes and a higher risk of fiber breakage during installation. In this study, we proposed using the bonding line between the shear web and spar cap as a new installation position of embedded OFSs for estimating the deflection of the blades. Laboratory coupon tests were undertaken preliminarily to confirm the strain measuring capability of embedded FBG sensors in adhesive layers, and the obtained values were verified by comparison with results obtained by electrical strain gauges and finite element analysis. We performed static loading tests on a 100 kW composite wind turbine blade to evaluate its deflections using embedded FBG sensors positioned in the bonding line. The deflections were estimated by classical beam theory considering a rigid body rotation near the tip of the blade. The evaluated tip deflections closely matched those measured by a linear variable differential transformer. Therefore, we verified the capability of embedded FBG sensors for evaluating the deflections of wind turbine blades. In addition, we confirmed that the bonding line between the shear web and spar cap is a practical location to embed the FBG sensors. (paper)

  1. Influence of loading distribution on the performance of high pressure turbine blades

    Science.gov (United States)

    Corriveau, Daniel

    Midspan measurements were made in a transonic wind tunnel for three High Pressure (HP) turbine blade cascades at both design and off-design incidences. Comparisons with two-dimensional numerical simulations of the cascade flow were also made. The baseline profile is the midspan section of a HP turbine blade of fairly recent design. It is considered mid-loaded. To gain a better understanding of blade loading limits and the influence of loading distributions, the profile of the baseline airfoil was modified to create two new airfoils having aft-loaded and front-loaded pressure distributions. Tests were performed for exit Mach numbers between 0.6 and 1.2. In addition, measurements were made for an extended range of Reynolds numbers for constant Mach numbers of 0.6, 0.85, 0.95 and 1.05. At the design exit Mach number of 1.05 and at design incidence, the aft-loaded airfoil showed a reduction of almost 20% in the total pressure losses compared with the baseline airfoil. Based on the analysis of wake traverse data and base pressure measurements combined with numerical results, it was found that the poorer loss performance of the baseline mid-loaded profile compared to the aft-loaded blade could be attributed to the former's higher rear suction side curvature, which resulted in higher flow velocity in that region, which, in turn, contributed to reducing the base pressure. The lower base pressure at the trailing edge resulted in a stronger trailing edge shock system for the mid-loaded blade. This shock system increased the losses for the mid-loaded baseline profile when compared to the aft-loaded profile. On the negative side, it was also found that as Mach numbers were increased beyond the design value the performance of the aft-loaded blade deteriorated rapidly. Under such conditions, the front-loaded airfoil showed generally inferior performance compared with the baseline airfoil. At off-design incidence, the aft-loaded blade maintained a superior loss performance over a

  2. Large-scale Wind Turbine Blade Redesign Based on Reverse Engineering%大型风能发电机组叶片反求再设计

    Institute of Scientific and Technical Information of China (English)

    陶庆; 孙文磊

    2015-01-01

    叶片的外形设计和翼型的选择等都能影响风机性能和产能效率。提出一种大型风能发电机组叶片反求再设计的原理和方法,通过对大型风能发电机组叶片反求测量、大型风能发电机组叶片逆向CAD建模,寻找几何特征,探索制约叶片形状的基本因素,确定叶片截面参数计算公式,利用所开发的叶片翼型自动生成系统,完成了叶片的再设计,并得到了实际应用。%The large⁃scale wind turbine blade contour design and the choice of wing section affect the wind turbine performance and energy efficiency. A redesign principle and method for large⁃scale wind turbine blade was presented which was based on the analy⁃sis of blade CAD model from reverse engineering, looking for geometric features, exploring basic constraint factors on blade shape, and determining parameters of blade cross section calculation formula. Blade design was completed using this self⁃developed blade aerofoil automatic generation system. The results show that the redesign meets the production requirements.

  3. Barriers to Exercise in Younger and Older Non-Exercising Adult Women: A Cross Sectional Study in London, United Kingdom

    OpenAIRE

    Ansari, Walid El; Lovell, Geoff

    2009-01-01

    A survey of 100 women in the south of London, United Kingdom (UK) compared exercise barrier intensities between non-exercising younger (20-27 years) and older (28-35 years) adult women; and examined childcare duties as perceived barriers to exercise. Perceived barriers to exercise were examined using an Exercise Benefits/Barriers Scale (EBBS) comprising four subscales (exercise milieu; time expenditure; physical exertion; family discouragement). Participants’ number of children was also noted...

  4. Adhesive Joints in Wind Turbine Blades

    DEFF Research Database (Denmark)

    Jørgensen, Jeppe Bjørn

    to be determined in several different ways. The accuracy of different ways of measuring residual stresses in the adhesive was tested by applying five different methods on a single sandwich test specimen (laminate/adhesive/laminate) that was instrumented with strain gauges and fiber Bragg gratings. Quasi...... of the project is to develop new- and to improve the existing design rules for adhesive joints in wind turbine blades. The first scientific studies of adhesive joints were based on stress analysis, which requires that the bond-line is free of defects, but this is rarely the case for a wind turbine blade. Instead...... curing and test temperatures) on the formation of transverse cracks in the adhesive were tested experimentally. It was assumed that the transverse cracks evolved due to a combination of mechanical- and residual stresses in the adhesive. A new approach was developed that allows the residual stress...

  5. Souvenir knife: a retained transcranial knife blade.

    Science.gov (United States)

    Davis, Neil L; Kahana, Tzipi; Hiss, Jehuda

    2004-09-01

    Upon necroscopic examination of a homeless male found comatose in the street and pronounced dead at a medical center 12 hours later, a sharp tip of a knife lodged in the right parietal region of his skull was incidentally discovered. The blade transected the diploe and penetrated the cerebral cortex. Subsequent police investigation revealed that this was the remnant of a stabbing attempt on his life several months prior to his death. The cause of death was determined to be unrelated to the metallic blade fragment, thus making it a truly incidental and rare finding of a "souvenir knife." Nevertheless, since the injury sustained in the stabbing was potentially life threatening, the investigation into that assault was reopened.A case report is presented, along with a brief review of the literature on "souvenir objects."

  6. Structural Reliability of Wind Turbine Blades

    DEFF Research Database (Denmark)

    Dimitrov, Nikolay Krasimirov

    turbine blades. The main purpose is to draw a clear picture of how reliability-based design of wind turbines can be done in practice. The objectives of the thesis are to create methodologies for efficient reliability assessment of composite materials and composite wind turbine blades, and to map...... the uncertainties in the processes, materials and external conditions that have an effect on the health of a composite structure. The study considers all stages in a reliability analysis, from defining models of structural components to obtaining the reliability index and calibration of partial safety factors...... by developing new models and standards or carrying out tests The following aspects are covered in detail: ⋅ The probabilistic aspects of ultimate strength of composite laminates are addressed. Laminated plates are considered as a general structural reliability system where each layer in a laminate is a separate...

  7. 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.

  8. 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.

  9. Derivation of airfoil characteristics for the LM 19.1 blade based on 3D CFD rotor calculations

    Energy Technology Data Exchange (ETDEWEB)

    Bak, C; Soerensen, N N; Madsen, H A [Risoe National Lab., Roskilde (Denmark)

    1999-03-01

    Airfoil characteristics for the LM 19.1 blade are derived from 3D CFD computations on a full-scale 41-m rotor. Based on 3D CFD the force distributions on the blades are determined, from which airfoil characteristics are derived using the momentum theory. The final airfoil characteristics are constructed using both wind tunnel measurements and 3D CFD. Compared to 2D wind tunnel measurements they show a low lift in stall for the airfoil sections at the tip. At the airfoil sections at the inner part of the blade, they show a high lift in stall. At about 60% radius the lift agrees well to 2D wind tunnel measurements. Aero-elastic calculations using the final airfoil characteristics show good agreement to measured power and flap moments. Furthermore, a fatigue load analysis shows a reduction of up to 15% of the load compared to commonly used data. (au)

  10. Paleoseismology of the Southern Section of the Black Mountains and Southern Death Valley Fault Zones, Death Valley, United States

    Science.gov (United States)

    Sohn, Marsha S.; Knott, Jeffrey R.; Mahan, Shannon

    2014-01-01

    The Death Valley Fault System (DVFS) is part of the southern Walker Lane–eastern California shear zone. The normal Black Mountains Fault Zone (BMFZ) and the right-lateral Southern Death Valley Fault Zone (SDVFZ) are two components of the DVFS. Estimates of late Pleistocene-Holocene slip rates and recurrence intervals for these two fault zones are uncertain owing to poor relative age control. The BMFZ southernmost section (Section 1W) steps basinward and preserves multiple scarps in the Quaternary alluvial fans. We present optically stimulated luminescence (OSL) dates ranging from 27 to 4 ka of fluvial and eolian sand lenses interbedded with alluvial-fan deposits offset by the BMFZ. By cross-cutting relations, we infer that there were three separate ground-rupturing earthquakes on BMFZ Section 1W with vertical displacement between 5.5 m and 2.75 m. The slip-rate estimate is ∼0.2 to 1.8 mm/yr, with an earthquake recurrence interval of 4,500 to 2,000 years. Slip-per-event measurements indicate Mw 7.0 to 7.2 earthquakes. The 27–4-ka OSL-dated alluvial fans also overlie the putative Cinder Hill tephra layer. Cinder Hill is offset ∼213 m by SDVFZ, which yields a tentative slip rate of 1 to 8 mm/yr for the SDVFZ.

  11. An aerodynamic study on flexed blades for VAWT applications

    Science.gov (United States)

    Micallef, Daniel; Farrugia, Russell; Sant, Tonio; Mollicone, Pierluigi

    2014-12-01

    There is renewed interest in aerodynamics research of VAWT rotors. Lift type, Darrieus designs sometimes use flexed blades to have an 'egg-beater shape' with an optimum Troposkien geometry to minimize the structural stress on the blades. While straight bladed VAWTs have been investigated in depth through both measurements and numerical modelling, the aerodynamics of flexed blades has not been researched with the same level of detail. Two major effects may have a substantial impact on blade performance. First, flexing at the equator causes relatively strong trailing vorticity to be released. Secondly, the blade performance at each station along the blade is influenced by self-induced velocities due to bound vorticity. The latter is not present in a straight bladed configuration. The aim of this research is to investigate these effects in relation to an innovative 4kW wind turbine concept being developed in collaboration with industry known as a self-adjusting VAWT (or SATVAWT). The approach used in this study is based on experimental and numerical work. A lifting line free-wake vortex model was developed. Wind tunnel power and hot-wire velocity measurements were performed on a scaled down, 60cm high, three bladed model in a closed wind tunnel. Results show a substantial axial wake induction at the equator resulting in a lower power generation at this position. This induction increases with increasing degree of flexure. The self-induced velocities caused by blade bound vorticity at a particular station was found to be relatively small.

  12. Influence of delayed excitation on vibrations of turbine blades couple

    Directory of Open Access Journals (Sweden)

    Půst L.

    2013-06-01

    Full Text Available In the presented paper, the computational model of the turbine blade couple is investigated with the main attention to the influence two harmonic excitation forces, having the same frequency and amplitude but with moderate delay in time. Time delay between the exciting harmonic forces depends on the revolutions of bladed disk, on the number of blades on a rotating disk and on the number of stator blades. The reduction of resonance vibrations realized by means of dry friction between the shroud blade-heads increases roughly proportional to the difference of stator and rotor blade-numbers and also to the magnitude of dry friction force. From the analysis of blade couple with direct contact it was proved that the increase of friction forces causes decrease of resonance peaks, but the influence of elastic micro-deformations in the contact surfaces (modeled e.g. by the modified Coulomb dry friction law is rather small. Analysis of a blade couple with a friction element shows that the lower number of stator blades has negligible influence on the amplitudes of both blades, but decreases amplitudes of the friction element oscillations. Similarly the increase of friction forces causes a decrease of resonance peaks, but an increase of friction element amplitudes.

  13. A Take Stock of Turbine Blades Failure Phenomenon

    Science.gov (United States)

    Roy, Abhijit

    2018-02-01

    Turbine Blade design and engineering is one of the most complicated and important aspects of turbine technology. Experiments with blades can be simple or very complicated, depending upon parameters of analysis. Turbine blades are subjected to vigorous environments, such as high temperatures, high stresses, and a potentially high vibration environment. All these factors can lead to blade failures, which can destroy the turbine, and engine, so careful design is the prime consideration to resist those conditions. A high cycle of fatigue of compressor and turbine blades due to high dynamic stress caused by blade vibration and resonance within the operating range of machinery is common failure mode for turbine machine. Continuous study and investigation on failure of turbine blades are going on since last five decades. Some review papers published during these days aiming to present a review on recent studies and investigations done on failures of turbine blades. All the detailed literature related with the turbine blades has not been described but emphasized to provide all the methodologies of failures adopted by various researches to investigate turbine blade. This paper illustrate on various factors of failure.

  14. 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.

  15. Unsteady modelling of the oscillating S809 aerofoil and NREL phase VI parked blade using the Beddoes-Leishman dynamic stall model

    International Nuclear Information System (INIS)

    Gonzalez, Alvaro; Munduate, Xabier

    2007-01-01

    An implementation of the Beddoes-Leishman dynamic stall model has been developed at CENER, for modelling the unsteady aerodynamics on oscillating blade sections. The parameters of the model were adjusted for the S809 aerofoil, using an optimization based on genetic algorithms, and taking into account the values found in the literature and the physics of the aerodynamic process. Once the parameters were fixed to a unique set, oscillating cases of the 2D S809 aerofoil were computed, and compared with experimental data. Thus, the accuracy of the model was evaluated. On the other hand, oscillating cases of different span stations of the NREL phase VI parked blade were computed and compared with experimental data, to analyze the three-dimensionality of the dynamic stall on the blade sections. For the unsteady computations on the blade, the model was fed with the steady data of the blade section, to directly consider the geometry influence. In general, the results of the computations for the 2D aerofoil and 3D blade sections were very encouraging

  16. Vibration of circular bladed disk with imperfections

    Czech Academy of Sciences Publication Activity Database

    Půst, Ladislav; Pešek, Luděk

    2011-01-01

    Roč. 21, č. 10 (2011), s. 2893-2904 ISSN 0218-1274 R&D Projects: GA ČR GA101/09/1166 Institutional research plan: CEZ:AV0Z20760514 Keywords : circular bladed disk * vibration * imperfection * nonlinear damping Subject RIV: BI - Acoustics Impact factor: 0.755, year: 2011 http://www.worldscinet.com/ijbc/21/2110/S0218127411030210.html

  17. Materials for Wind Turbine Blades: An Overview

    DEFF Research Database (Denmark)

    Mishnaevsky, Leon; Branner, Kim; Petersen, Helga Nørgaard

    2017-01-01

    A short overview of composite materials for wind turbine applications is presented here. Requirements toward the wind turbine materials, loads, as well as available materials are reviewed. Apart from the traditional composites for wind turbine blades (glass fibers/epoxy matrix composites), natural...... composites, hybrid and nanoengineered composites are discussed. Manufacturing technologies for wind turbine composites, as well their testing and modelling approaches are reviewed....

  18. Materials for Wind Turbine Blades: An Overview.

    Science.gov (United States)

    Mishnaevsky, Leon; Branner, Kim; Petersen, Helga Nørgaard; Beauson, Justine; McGugan, Malcolm; Sørensen, Bent F

    2017-11-09

    A short overview of composite materials for wind turbine applications is presented here. Requirements toward the wind turbine materials, loads, as well as available materials are reviewed. Apart from the traditional composites for wind turbine blades (glass fibers/epoxy matrix composites), natural composites, hybrid and nanoengineered composites are discussed. Manufacturing technologies for wind turbine composites, as well their testing and modelling approaches are reviewed.

  19. WIMS-IST/DRAGON-IST side-step calculation of reactivity device and structural material incremental cross sections for Wolsong NPP Unit 1

    International Nuclear Information System (INIS)

    Dahmani, M.; McArthur, R.; Kim, B.G.; Kim, S.M.; Seo, H.-B.

    2008-01-01

    This paper describes the calculation of two-group incremental cross sections for all of the reactivity devices and incore structural materials for an RFSP-IST full-core model of Wolsong NPP Unit 1, in support of the conversion of the reference plant model to two energy groups. This is of particular interest since the calculation used the new standard 'side-step' approach, which is a three-dimensional supercell method that employs the Industry Standard Toolset (IST) codes DRAGON-IST and WIMS-IST with the ENDF/B-VI nuclear data library. In this technique, the macroscopic cross sections for the fuel regions and the device material specifications are first generated using the lattice code WIMS-IST with 89 energy groups. DRAGON-IST then uses this data with a standard supercell modelling approach for the three-dimensional calculations. Incremental cross sections are calculated for the stainless-steel adjuster rods (SS-ADJ), the liquid zone control units (LZCU), the shutoff rods (SOR), the mechanical control absorbers (MCA) and various structural materials, such as guide tubes, springs, locators, brackets, adjuster cables and support bars and the moderator inlet nozzle deflectors. Isotopic compositions of the Zircaloy-2, stainless steel and Inconel X-750 alloys in these items are derived from Wolsong NPP Unit 1 history dockets. Their geometrical layouts are based on applicable design drawings. Mid-burnup fuel with no moderator poison was assumed. The incremental cross sections and key aspects of the modelling are summarized in this paper. (author)

  20. Contributions to a shallow aquifer study by reprocessed seismic sections from petroleum exploration surveys, eastern Abu Dhabi, United Arab Emirates

    Science.gov (United States)

    Woodward, D.

    1994-01-01

    The US Geological Survey, in cooperation with the National Drilling Company of Abu Dhabi, is conducting a 4-year study of the fresh and slightly saline groundwater resources of the eastern Abu Dhabi Emirate. Most of this water occurs in a shallow aquifer, generally less than 150 m deep, in the Al Ain area. A critical part of the Al Ain area coincides with a former petroleum concession area where about 2780 km of vibroseis data were collected along 94 seismic lines during 1981-1983. Field methods, acquistion parameters, and section processing were originally designed to enhance reflections expected at depths ranging from 5000 to 6000 m, and subsurface features directly associated with the shallow aquifer system were deleted from the original seismic sections. The original field tapes from the vibroseis survey were reprocessed in an attempt to extract shallow subsurface information (depths less than 550 m) for investigating the shallow aquifer. A unique sequence of reproccessing parameters was established after reviewing the results from many experimental tests. Many enhancements to the resolution of shallow seismic reflections resulted from: (1) application of a 20-Hz, low-cut filter; (2) recomputation of static corrections to a datum nearer the land surface; (3) intensive velocity analyses; and (4) near-trace muting analyses. The number, resolution, and lateral continuity of shallow reflections were greatly enhanced on the reprocessed sections, as was the delineation of shallow, major faults. Reflections on a synthetic seismogram, created from a borehole drilled to a depth of 786 m on seismic line IQS-11, matcheddprecisely with shallow reflections on the reprocessed section. The 33 reprocessed sections were instrumental in preparing a map showing the major structural features that affect the shallow aquifer system. Analysis of the map provides a better understanding of the effect of these shallow features on the regional occurrence, movement, and quality of

  1. Calculation of blade-data for the Hamilton standard structural analysis of the composite blade for the 18 meter diameter rotor and a comparison with FFA-calculation

    Energy Technology Data Exchange (ETDEWEB)

    Lundemo, C

    1979-04-01

    Section property data for the composite blade manufactured by Karlskronavarvet was calculated for the analysis performed by Hamilton Standard. The HS investigation was carried out for various operating conditions, including dynamic response loads, stresses, frequencies and dynamic stability. The Hamilton Standard results has been compared with the FFA (The Aeronautical Research Institute of Sweden) calculation. The results show that the stresses and moments calculated by HS never exceed the allowable levels for the hinged hub configuration. The natural frequencies seem to agree quite well with the measured frequencies. In the input data of the Hamilton Standard dynamic response analysis a too far aft position of the cordwise center of gravity of the outher third of the blade was used. Correct position will give lower stresses.

  2. Pitched Blade Turbine Efficiency at Particle Suspension

    Directory of Open Access Journals (Sweden)

    D. Ceres

    2010-01-01

    Full Text Available Mixing suspensions is a very important hydraulic operation. The pitched six-blade turbine is a widely-used axial-flow impeller. This paper deals with effect relative impeller size and particle content on theefficiency of a pitched six-blade turbine at particle suspension. Two pitched six-blade turbines were used in model measurements of just suspension impeller speed. The ratios of the vessel to agitator diameter D/d were 3 and 4.5. The measurements were carried out in a dish-bottomed vessel 300 mm in diameter. The just suspension impeller speeds were measured using an electrochemical method, and were checked visually. A 2.5 % NaCl water solution was used as the liquid phase, and glass particles with four equivalent diameters between 0.18 and 0.89 mmand volumetric concentration from 2.5 % to 40% were usedasthesolid phase. The criterion values πs=Po√Fr'3(d/D7 were calculated from the particle suspension and power consumption measurements. The dependencies of πs on particle content cv show that larger agitators are more efficient for higher particle content.

  3. Noise aspects at aerodynamic blade optimisation projects

    Energy Technology Data Exchange (ETDEWEB)

    Schepers, J.G. [Netherlands Energy Research Foundation, Petten (Netherlands)

    1997-12-31

    This paper shows an example of an aerodynamic blade optimisation, using the program PVOPT. PVOPT calculates the optimal wind turbine blade geometry such that the maximum energy yield is obtained. Using the aerodynamic optimal blade design as a basis, the possibilities of noise reduction are investigated. The aerodynamic optimised geometry from PVOPT is the `real` optimum (up to the latest decimal). The most important conclusion from this study is, that it is worthwhile to investigate the behaviour of the objective function (in the present case the energy yield) around the optimum: If the optimum is flat, there is a possibility to apply modifications to the optimum configuration with only a limited loss in energy yield. It is obvious that the modified configurations emits a different (and possibly lower) noise level. In the BLADOPT program (the successor of PVOPT) it will be possible to quantify the noise level and hence to assess the reduced noise emission more thoroughly. At present the most promising approaches for noise reduction are believed to be a reduction of the rotor speed (if at all possible), and a reduction of the tip angle by means of low lift profiles, or decreased twist at the outboard stations. These modifications were possible without a significant loss in energy yield. (LN)

  4. Conjugate calculation of a film-cooled blade for improvement of the leading edge cooling configuration

    Directory of Open Access Journals (Sweden)

    Norbert Moritz

    2013-03-01

    Full Text Available Great efforts are still put into the design process of advanced film-cooling configurations. In particular, the vanes and blades of turbine front stages have to be cooled extensively for a safe operation. The conjugate calculation technique is used for the three-dimensional thermal load prediction of a film-cooled test blade of a modern gas turbine. Thus, it becomes possible to take into account the interaction of internal flows, external flow, and heat transfer without the prescription of heat transfer coefficients. The focus of the investigation is laid on the leading edge part of the blade. The numerical model consists of all internal flow passages and cooling hole rows at the leading edge. Furthermore, the radial gap flow is also part of the model. The comparison with thermal pyrometer measurements shows that with respect to regions with high thermal load a qualitatively and quantitatively good agreement of the conjugate results and the measurements can be found. In particular, the region in the vicinity of the mid-span section is exposed to a higher thermal load, which requires further improvement of the cooling arrangement. Altogether the achieved results demonstrate that the conjugate calculation technique is applicable for reasonable prediction of three-dimensional thermal load of complex cooling configurations for blades.

  5. Composite Structural Analysis of Flat-Back Shaped Blade for Multi-MW Class Wind Turbine

    Science.gov (United States)

    Kim, Soo-Hyun; Bang, Hyung-Joon; Shin, Hyung-Ki; Jang, Moon-Seok

    2014-06-01

    This paper provides an overview of failure mode estimation based on 3D structural finite element (FE) analysis of the flat-back shaped wind turbine blade. Buckling stability, fiber failure (FF), and inter-fiber failure (IFF) analyses were performed to account for delamination or matrix failure of composite materials and to predict the realistic behavior of the entire blade region. Puck's fracture criteria were used for IFF evaluation. Blade design loads applicable to multi-megawatt (MW) wind turbine systems were calculated according to the Germanischer Lloyd (GL) guideline and the International Electrotechnical Commission (IEC) 61400-1 standard, under Class IIA wind conditions. After the post-processing of final load results, a number of principal load cases were selected and converted into applied forces at the each section along the blade's radius of the FE model. Nonlinear static analyses were performed for laminate failure, FF, and IFF check. For buckling stability, linear eigenvalue analysis was performed. As a result, we were able to estimate the failure mode and locate the major weak point.

  6. Computational study of a High Pressure Turbine Nozzle/Blade Interaction

    Science.gov (United States)

    Kopriva, James; Laskowski, Gregory; Sheikhi, Reza

    2015-11-01

    A downstream high pressure turbine blade has been designed for this study to be coupled with the upstream uncooled nozzle of Arts and Rouvroit [1992]. The computational domain is first held to a pitch-line section that includes no centrifugal forces (linear sliding-mesh). The stage geometry is intended to study the fundamental nozzle/blade interaction in a computationally cost efficient manner. Blade/Nozzle count of 2:1 is designed to maintain computational periodic boundary conditions for the coupled problem. Next the geometry is extended to a fully 3D domain with endwalls to understand the impact of secondary flow structures. A set of systematic computational studies are presented to understand the impact of turbulence on the nozzle and down-stream blade boundary layer development, resulting heat transfer, and downstream wake mixing in the absence of cooling. Doing so will provide a much better understanding of stage mixing losses and wall heat transfer which, in turn, can allow for improved engine performance. Computational studies are performed using WALE (Wale Adapted Local Eddy), IDDES (Improved Delayed Detached Eddy Simulation), SST (Shear Stress Transport) models in Fluent.

  7. A concept study of a carbon spar cap design for a 80m wind turbine blade

    International Nuclear Information System (INIS)

    Rosemeier, M; Bätge, M

    2014-01-01

    The buckling resistance is a key design driver for large wind turbine blades with a significant influence on the material costs. During the structural design process the choice was made for carbon spar caps and two shear webs, which were set relatively far apart in order to stabilize the panels. This design presented a major challenge for the stability of the spar caps. The topology of these spar caps has been modified with regard to stability, comparing a continuous spar cap with split spar cap concepts and considering both lay-ups with hybrid carbon glass spar caps or sandwich concepts. Within those concepts, parametric studies were conducted varying different geometrical parameters of the spar caps and its layups. In order to determine the buckling resistance of the spar cap, an analytical model considering a 2D cross section discretized blade model was utilized to select the basic concept, after which a 3D numerical finite element model taking the whole blade into account was used to evaluate the chosen design concepts. The stability limit state analysis was conducted according to the certification scheme of GL guideline 2012. The various concepts were evaluated based on the blade's mass, tip deflection and modal properties. The results of this design process of the spar caps and the evaluation of the used analysis tools are presented within the paper

  8. Ergonomic Evaluation of Vibrations of a Rototiller with New Blade

    Directory of Open Access Journals (Sweden)

    H Gholami

    2017-10-01

    Full Text Available Introduction One of the most important problems arising with operation of the conventional rototillers is severe vibration of the machine handle which is transmitted to the user’s hands, arms and shoulders. Long period exposure of the hand-transmitted vibration may cause various diseases such as white finger syndrome. Therefore in this study, vibrations of a new type of rototiller with ridged blades were investigated at the position of handle/hand interface in different working conditions. Finally, the maximum allowable exposure time to the rototiller users in continuous tillage operation was obtained according to ISO 5349-1. Materials and Methods Experiments were carried out in one of the farms with silty clay soil texture, located in Sari city, Mazandaran province, Iran. Vibration measurements were performed according to ISO 5349-1 and ISO 5349-2 standards in two different modes, including in situ mode and tillage mode. Vibrational parameters were obtained in three blade rotational speeds, i.e., low speed (140-170 rpm, medium speed (170-200, and high speed (200-230. Blade rotational speed varied by changing engine speed using the throttle control lever. In each experiment, different vibrational values were individually recorded in three directions (x, y, and z. Experimental design and data analysis were performed in a Randomized Complete Block Design with three replications using the SPSS16 software. Results and Discussion Based on the obtained results in this study, the RMS of acceleration increased by increasing in rotational speed for all of the conducted experiments. The reason is that number of cutting per unit of time and consequently the frequency of changing in the dynamic forces exerting on the blades dramatically increases with increasing the rotational speed of the blades. Noteworthy is that in most cases the variation of acceleration in the tillage mode showed similar trend with vibrational values in the idling mode. This

  9. Accounting of possibilities of blade oscillation emergence at the calculation of operating wheel of turbomolecular vacuum pump

    International Nuclear Information System (INIS)

    Pereslavlev, A.V.

    1988-01-01

    Possibilities of blade oscillation emergence in the operating wheel of turbomolecular vacuum pump (TVP) are considered. Permissible value of safety factor for tensile strength in the operating wheel blade root section, at which the necessary fatigue limit of a material is provided for (k=2 for aluminium alloys and k=1.5 for VT-8 titanium alloy) is determined. Methods of calculating the main dimensions of blade operating wheel on the basis of the specified maximum pumping speed, taking account of possibilities of blade oscillation emergence are presented. Results of calculating the 4S max/πD 2 2 complex, characterizing maximum speed of operating wheel pumping, depending on permissible tensipn in the blade root section (σ), are given. It is shown that (σ increase above (2.5 2.7)x10 8 Pa for aluminium alloys and above ∼ 4x10 8 Pa for VT titanium alloy don't cause increase of operating wheel maximum pumping speed. 8 refs.; 6 figs

  10. Technological assessment of local manufacturers for wind turbine blade manufacturing in Pakistan

    Science.gov (United States)

    Mahmood, Khurram; Haroon, General

    2012-11-01

    Composite materials manufacturing industry is one of the world's hi-tech industry. Manufacturing of wind turbine blades is one of the specialized fields requiring high degree of precision and composite manufacturing techniques. This paper identifies the industries specializing in the composite manufacturing and is able to manufacture wind turbines blades in Pakistan. In the second phase, their technology readiness level is determined, based on some factors and then a readiness level are assigned to them. The assigned technology readiness level will depict the absorptive capacity of each manufacturing unit and its capability to take on such projects. The individual readiness level of manufacturing unit will then be used to establish combined technology readiness level of Pakistan particularly for wind turbine blades manufacturing. The composite manufacturing industry provides many spin offs and a diverse range of products can be manufactured using this facility. This research will be helpful to categorize the strong points and flaws of local industry for the gap analysis. It can also be used as a prerequisite study before the evaluation of technologies and specialties to improve the industry of the country for the most favorable results. This will form a basic data base which can be used for the decision making related to transfer of technology, training of local skilled workers and general up-gradation of the local manufacturing units.

  11. Factors associated with self-medication among expatriate high school students: a cross-sectional survey in United Arab Emirates

    Directory of Open Access Journals (Sweden)

    Syed Ilyas Shehnaz

    2013-09-01

    Full Text Available The study aimed to assess factors associated with self-medication (SM among expatriate high school students of United Arab Emirates using a validated questionnaire. Most common reasons for self-medication in 324 participating students were: presence of mild illness and previous experiences. High risk practices like altering the dose, discontinuation of medication and self-medication without adult guidance were observed. The likelihood of SM was 4.9 times (95%C.I.: 2.0-12.2 in students not utilizing private healthcare services than those who were utilizing these services. Increased efforts are needed to prevent the risks of self-medication in adolescents through healthcare education for both parents and adolescents.

  12. The comparative burden of mild, moderate and severe Fibromyalgia: results from a cross-sectional survey in the United States

    Directory of Open Access Journals (Sweden)

    Goldenberg Don

    2011-08-01

    Full Text Available Abstract Background Fibromyalgia (FM is characterized by chronic, widespread pain, fatigue, and other symptoms; yet few studies have comprehensively assessed its humanistic burden. This observational study evaluates the impact of FM severity on patients' symptoms, health-related quality of life (HRQoL, and productivity in the United States. Methods 203 FM subjects were recruited from 20 physician offices. Subjects completed a questionnaire including the EuroQol 5D (EQ-5D, Fibromyalgia Impact Questionnaire (FIQ, Multidimensional Assessment of Fatigue (MAF, Medical Outcomes Study Sleep Scale (MOS-SS, and Hospital Anxiety and Depression Scale (HADS and questions about demographics, pain and other symptoms, HRQoL and productivity. FIQ total scores were used to define FM severity, with 0- Results Mean (SD age was 47.9 (10.9; 95% were female. Most (92% were prescribed medication for FM; 24% and 66% reported moderate and severe FM, respectively. Mean (SD scores were: 6.3 (2.1 for pain intensity; 0.35 (0.35 for EQ-5D; 30.7 (14.2 for MAF; 57.5 (18.4 for MOS-SS Sleep Problems Index; 10.2 (4.8 for HADS anxiety and 9.4 (4.4 for HADS depression. Subjects with worse FM severity reported significantly increased pain severity, HRQoL, fatigue, sleep disturbance, anxiety and depression (p Conclusions FM imposes a substantial humanistic burden on patients in the United States, and leads to substantial productivity loss, despite treatment. This burden is higher among subjects with worse FM severity.

  13. Multi-spectral temperature measurement method for gas turbine blade

    Science.gov (United States)

    Gao, Shan; Feng, Chi; Wang, Lixin; Li, Dong

    2016-02-01

    One of the basic methods to improve both the thermal efficiency and power output of a gas turbine is to increase the firing temperature. However, gas turbine blades are easily damaged in harsh high-temperature and high-pressure environments. Therefore, ensuring that the blade temperature remains within the design limits is very important. There are unsolved problems in blade temperature measurement, relating to the emissivity of the blade surface, influences of the combustion gases, and reflections of radiant energy from the surroundings. In this study, the emissivity of blade surfaces has been measured, with errors reduced by a fitting method, influences of the combustion gases have been calculated for different operational conditions, and a reflection model has been built. An iterative computing method is proposed for calculating blade temperatures, and the experimental results show that this method has high precision.

  14. 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.

  15. Resonant vibration control of three-bladed wind turbine rotors

    DEFF Research Database (Denmark)

    Krenk, Steen; Svendsen, Martin Nymann; Høgsberg, Jan Becker

    2012-01-01

    Rotors with blades, as in wind turbines, are prone to vibrations due to the flexibility of the blades and the support. In the present paper a theory is developed for active control of a combined set of vibration modes in three-bladed rotors. The control system consists of identical collocated...... to influence of other nonresonant modes. The efficiency of the method isdemonstrated byapplication to a rotor with 42 m blades, where the sensor/actuator system is implemented in the form of an axial extensible strut near the root of each blade. The load is provided by a simple but fully threedimensional...... correlated wind velocity field. It is shown by numerical simulations that the active damping system can provide a significant reduction in the response amplitude of the targeted modes, while applying control moments to the blades that are about 1 order of magnitude smaller than the moments from the external...

  16. On the performance analysis of Savonius rotor with twisted blades

    Energy Technology Data Exchange (ETDEWEB)

    Saha, U.K.; Rajkumar, M. Jaya [Department of Mechanical Engineering, Indian Institute of Technology Guwahati, Guwahati-781 039 (India)

    2006-09-15

    The present investigation is aimed at exploring the feasibility of twisted bladed Savonius rotor for power generation. The twisted blade in a three-bladed rotor system has been tested in a low speed wind tunnel, and its performance has been compared with conventional semicircular blades (with twist angle of 0{sup o}). Performance analysis has been made on the basis of starting characteristics, static torque and rotational speed. Experimental evidence shows the potential of the twisted bladed rotor in terms of smooth running, higher efficiency and self-starting capability as compared to that of the conventional bladed rotor. Further experiments have been conducted in the same setup to optimize the twist angle. (author)

  17. Quality of doctoral nursing education in the United Kingdom: exploring the views of doctoral students and staff based on a cross-sectional questionnaire survey.

    Science.gov (United States)

    McKenna, Hugh; Keeney, Sinead; Kim, Mi Ja; Park, Chang Gi

    2014-07-01

    To evaluate the quality of doctoral education in nursing in the United Kingdom. In recent decades, doctoral education programmes in nursing are increasing worldwide. There are many reasons for this and concerns have been raised regarding the quality of provision in and across countries. To date, the quality of doctoral education on a global level has not been reported in the literature. This United Kingdom study is part of a seven country investigation into the quality of doctoral education in nursing (Australia, Japan, Korea, South Africa, Thailand, United Kingdom and United States of America). A quantitative study using a cross-sectional comparative survey design. An online survey was administered to collect the views of doctoral students and staff members on four domains: programme, faculty/staff, resource and evaluation. The study was carried out between 2010-2012. In most cases, staff perceived these more positively than students and the differences in perception were often statistically significant. Interestingly, many students rated the quality of supervision as excellent, whereas no staff member rated supervision this highly. The crucial importance of resources was confirmed in the path analysis of the four Quality of Doctoral Nursing Education domains. This demonstrates that investment in resources is much more cost-effective than investment in the other domains in relation to improving the overall quality of doctoral education in nursing. This study has wide-ranging implications for how the quality of doctoral education is monitored and enhanced. © 2013 John Wiley & Sons Ltd.

  18. 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.

  19. Influence of Thermal Effects During Blade-Casing Contact Experiments

    OpenAIRE

    Millecamps , Antoine; Brunel , Jean-François; Dufrenoy , Philippe; Garcin , François; Nucci , Marco

    2009-01-01

    International audience; In rotating machinery, notably in modern high efficiency compressors, a critical requirement for optimal performance consists in minimizing radial clearances between the rotating bladed disk and the casing. This solution significantly increases the risks of contact between rotating bladed disk and casing and may lead in specific conditions to catastrophic behavior (component failure, etc.). The physical phenomena and mechanisms involved in blade-casing contact interact...

  20. Aerodynamic investigation of winglets on wind turbine blades using CFD

    OpenAIRE

    Johansen, Jeppe; Sørensen, Niels N.

    2006-01-01

    The present report describes the numerical investigation of the aerodynamics around a wind turbine blade with a winglet using Computational Fluid Dynamics, CFD. Five winglets were investigated with different twist distribution and camber. Four of themwere pointing towards the pressure side (upstream) and one was pointing towards the suction side (downstream). Additionally, a rectangular modification of the original blade tip was designed with the same planform area as the blades with winglets...

  1. Investigating for failure of central ventilation fan blade

    International Nuclear Information System (INIS)

    Koo, Jae Raeyang; Ko Woo Sig; Kim, Yeon Hwan; Park, Kwang Ha

    2002-01-01

    During the operation, central ventilation fan stopped when switch 'on' condition. When central ventilation fan disassemble, ten blades of fan fractured. We have searched cause of failure. We had modeling one of the fan blades and analysis with computer programs. Thus we have find that fracture of central ventilation fan blades is alternative stress and vibration at hub. In this paper, we have described cause of failure

  2. Moving blade for steam turbines with axial flow

    International Nuclear Information System (INIS)

    Raschke, K.; Wehle, G.

    1976-01-01

    The invention concerns the improvement of the production of moving blades for steam turbines with axial flow, especially of multi-blades produced by welding of the top plates. It is proposed to weld the top plates before the moving blades are fitted into the rotor. Welding is this made much easier and can be carried out under protective gas and with better results. (UWI) [de

  3. Active Piezoelectric Vibration Control of Subscale Composite Fan Blades

    Science.gov (United States)

    Duffy, Kirsten P.; Choi, Benjamin B.; Provenza, Andrew J.; Min, James B.; Kray, Nicholas

    2012-01-01

    As part of the Fundamental Aeronautics program, researchers at NASA Glenn Research Center (GRC) are investigating new technologies supporting the development of lighter, quieter, and more efficient fans for turbomachinery applications. High performance fan blades designed to achieve such goals will be subjected to higher levels of aerodynamic excitations which could lead to more serious and complex vibration problems. Piezoelectric materials have been proposed as a means of decreasing engine blade vibration either through a passive damping scheme, or as part of an active vibration control system. For polymer matrix fiber composite blades, the piezoelectric elements could be embedded within the blade material, protecting the brittle piezoceramic material from the airflow and from debris. To investigate this idea, spin testing was performed on two General Electric Aviation (GE) subscale composite fan blades in the NASA GRC Dynamic Spin Rig Facility. The first bending mode (1B) was targeted for vibration control. Because these subscale blades are very thin, the piezoelectric material was surface-mounted on the blades. Three thin piezoelectric patches were applied to each blade two actuator patches and one small sensor patch. These flexible macro-fiber-composite patches were placed in a location of high resonant strain for the 1B mode. The blades were tested up to 5000 rpm, with patches used as sensors, as excitation for the blade, and as part of open- and closed-loop vibration control. Results show that with a single actuator patch, active vibration control causes the damping ratio to increase from a baseline of 0.3% critical damping to about 1.0% damping at 0 RPM. As the rotor speed approaches 5000 RPM, the actively controlled blade damping ratio decreases to about 0.5% damping. This occurs primarily because of centrifugal blade stiffening, and can be observed by the decrease in the generalized electromechanical coupling with rotor speed.

  4. Turbine blade having a constant thickness airfoil skin

    Science.gov (United States)

    Marra, John J

    2012-10-23

    A turbine blade is provided for a gas turbine comprising: a support structure comprising a base defining a root of the blade and a framework extending radially outwardly from the base, and an outer skin coupled to the support structure framework. The skin has a generally constant thickness along substantially the entire radial extent thereof. The framework and the skin define an airfoil of the blade.

  5. Stress analysis and life prediction of gas turbine blade

    Science.gov (United States)

    Hsiung, H. C.; Dunn, A. J.; Woodling, D. R.; Loh, D. L.

    1988-01-01

    A stress analysis procedure is presented for a redesign of the Space Shuttle Main Engine high pressure fuel turbopump turbine blades. The analysis consists of the one-dimensional scoping analysis to support the design layout and the follow-on three-dimensional finite element analysis to confirm the blade design at operating loading conditions. Blade life is evaluated based on high-cycle fatigue and low-cycle fatigue.

  6. Application of heterogeneous blading systems is the way for improving efficiency of centrifugal energy pumps

    Science.gov (United States)

    Pochylý, F.; Haluza, M.; Fialová, S.; Dobšáková, L.; Volkov, A. V.; Parygin, A. G.; Naumov, A. V.; Vikhlyantsev, A. A.; Druzhinin, A. A.

    2017-11-01

    The results of independent research implemented by the teams of authors representing the Brno University of technology (Czech Republic) and Moscow Power Engineering Institute National Research University (Russia) are presented and compared. The possibilities for improving the energy efficiency of slow-speed centrifugal pumps (with a specific speed coefficient n s engineering—in thermal power stations, in heat electric-power stations, in nuclear power plants, and in boiler rooms—were investigated. These are supply pumps, condensate pumps, precharge pumps, etc. The pumps with such values of n s are widely used in some technological cycles of oil-and-gas and chemical industries too. The research was focused on achieving the shape of the pump efficiency characteristics providing a significant extension of its effective working zone and increasing its integrated efficiency. The results were obtained based on new approaches to the formation of a blading system of an impeller of a slow-speed centrifugal pump different from the traditional blading system. The analytical dependences illustrating the influence of individual geometry of a blading system on the efficiency were presented. The possibilities of purposeful changing of its structure were demonstrated. It was experimentally confirmed that use of the innovative blading system makes it possible to increase the pump efficiency by 1-4% (in the experiments for the pumps with n s = 33 and 55) and to extend its efficient working zone approximately by 15-20% (in the experiment for the pumps with n s = 33 and 66). The latter is especially important for the supply pumps of NPP power units. The experimental results for all investigated pumps are presented in comparison with the characteristics of the efficiency provided by the blading systems designed by traditional methods.

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

    Science.gov (United States)

    Nowicki, Nathalie

    2016-01-01

    deflection measurement of said blades and all theory is today based on the theory developed for full scale helicopters. This report thus intends to highlight the problems that come with blade deflection theory and measurements for multicopters. This thesis starts with the introduction and problem formulation where the grounds for what the report contains are laid out. Then a literature review of the research within the area follows where previous and current research and methods are presented. In the background information and theory relevant to the area are presented. After that the methods and set up of the different experimental and computer simulation approaches are depicted. In the results section the obtained results are presented and compared. Lastly there is a discussion where the results and methods are evaluated and analyzed, followed by the most important conclusions.

  8. A New Hoe Blade for Inter-Row Weeding

    DEFF Research Database (Denmark)

    Green, O.; Znova, L.; Melander, Bo

    2016-01-01

    and weeds are relatively small. The term ‘Ducksfoot’ covers a range of hoe blade configurations where all have some resemblance with the shape of a ducks foot. However, the ‘Ducksfoot’ blade is not an optimal solution for weed control in narrow inter-row spaces. Several disadvantages have been encountered...... and the draft forces needed to pull it were approx. half those measured for a ‘Ducksfoot’ blade. The weeding features of the new L-blade will be further studied under field conditions....

  9. Static Structural and Modal Analysis of Gas Turbine Blade

    Science.gov (United States)

    Ranjan Kumar, Ravi; Pandey, K. M., Prof.

    2017-08-01

    Gas turbine is one of the most versatile items of turbo machinery nowadays. It is used in different modes such as power generation, oil and gas, process plants, aviation, domestic and related small industries. This paper is based on the problems concerning blade profile selection, material selection and turbine rotor blade vibration that seriously impact the induced stress-deformation and structural functioning of developmental gas turbine engine. In this paper for generating specific power by rotating blade at specific RPM, blade profile and material has been decided by static structural analysis. Gas turbine rotating blade RPM is decided by Modal Analysis so that the natural frequency of blade should not match with the excitation frequency. For the above blade profile has been modeled in SOLIDWORKS and analysis has been done in ANSYS WORKBENCH 14. Existing NACA6409 profile has been selected as base model and then it is modified by bending it through 72.5° and 145°. Hence these three different blade profiles have been analyzed for three different materials viz. Super Alloy X, Nimonic 80A and Inconel 625 at three different speed viz. 20000, 40000 and 60000RPM. It is found that NACA6409 with 72.5° bent gives best result for all material at all speed. Among all the material Inconel 625 gives best result. Hence Blade of Inconel 625 having 72.5° bent profile is the best combination for all RPM.

  10. Modal characteristics and fatigue strength of compressor blades

    International Nuclear Information System (INIS)

    Kim, Kyung Kook; Lee, Young Shin

    2014-01-01

    High-cycle fatigue (HCF) has been identified as one of the primary causes of gas turbine engine failure. The modal characteristics and endurance strength of a 5 MW gas turbine engine blade developed by Doosan Heavy Industries and Construction Co., Ltd. in HCF fracture were verified through analysis and tests to determine the reliability of the compressor blade. A compressor blade design procedure that considers HCF life was performed in the following order: airfoil and blade profile design, modal analysis, stress distribution test, stress endurance limit test, and fatigue life verification. This study analyzed the Campbell diagram and estimated resonance risk on the basis of the natural frequency analysis and modal test of the compressor blade to guarantee safe and operational reliability. In addition, the maximum stress point of the compressor blade was determined through stress distribution analysis and test. The bonding point of the strain gage was determined by using fatigue test. Stress endurance limit test was performed based on the results of these tests. This research compared and verified the modal characteristics and endurance strengths of the compressor blades to prevent HCF fracture, which is among the major causes of gas turbine engine damage. A fatigue life design procedure of compressor blades was established. The 5 MW class gas turbine compressor blade is well designed in terms of resonance stability and fatigue endurance limit.

  11. Modal characteristics and fatigue strength of compressor blades

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Kyung Kook [Doosan Heavy Industries and Construction, Changwon (Korea, Republic of); Lee, Young Shin [Chungnam National University, Daejeon (Korea, Republic of)

    2014-04-15

    High-cycle fatigue (HCF) has been identified as one of the primary causes of gas turbine engine failure. The modal characteristics and endurance strength of a 5 MW gas turbine engine blade developed by Doosan Heavy Industries and Construction Co., Ltd. in HCF fracture were verified through analysis and tests to determine the reliability of the compressor blade. A compressor blade design procedure that considers HCF life was performed in the following order: airfoil and blade profile design, modal analysis, stress distribution test, stress endurance limit test, and fatigue life verification. This study analyzed the Campbell diagram and estimated resonance risk on the basis of the natural frequency analysis and modal test of the compressor blade to guarantee safe and operational reliability. In addition, the maximum stress point of the compressor blade was determined through stress distribution analysis and test. The bonding point of the strain gage was determined by using fatigue test. Stress endurance limit test was performed based on the results of these tests. This research compared and verified the modal characteristics and endurance strengths of the compressor blades to prevent HCF fracture, which is among the major causes of gas turbine engine damage. A fatigue life design procedure of compressor blades was established. The 5 MW class gas turbine compressor blade is well designed in terms of resonance stability and fatigue endurance limit.

  12. Accelerated rain erosion of wind turbine blade coatings

    DEFF Research Database (Denmark)

    Zhang, Shizhong

    . There are four chapters in the thesis. In chapter 1, a literature survey provides background information to the field. Topics discussed are the global wind energy development, possible wind turbine constructions, blade structures and materials, blade coatings, and liquid erosion mechanisms. In chapter 2......During operation, the fast-moving blades of wind turbines are exposed to continuous impacts with rain droplets, hail, insects, or solid particles. This can lead to erosion of the blades, whereby the electrical efficiency is compromised and expensive repairs may be required. One possible solution...

  13. Fracture analysis of adhesive joints in wind turbine blades

    DEFF Research Database (Denmark)

    Eder, Martin Alexander; Bitsche, Robert

    2015-01-01

    Modern wind turbine rotor blades are usually made from fibre-reinforced composite subcomponents. In the final assembly stage, these subcomponents are bonded together by several adhesive joints. One important adhesive joint is situated at the trailing edge, which refers to the downstream edge where...... the air-flow rejoins and leaves the blade. Maintenance inspections of wind turbine rotor blades show that among other forms of damage, local debonding of the shells along the trailing edge is a frequent failure type. The cause of trailing edge failure in wind turbine blades is complex, and detailed...

  14. Contactless Diagnostics of Turbine Blade Vibration and Damage

    International Nuclear Information System (INIS)

    Prochazka, Pavel; Vanek, Frantisek

    2011-01-01

    The study deals with the contactless diagnostic method used for the identification of steam turbine blade strain, vibration and damage. The tip-timing method based on the evaluation of time differences of blade passages in different rotor revolutions has been modified and improved to provide more precise and reliable results. A new approach to the analysis of the amplitude and time differences of impulse signals generated by a blade passage has been applied. Amplitudes and frequencies of vibrations and static position of blades ascertained by the diagnostic process are used to establish the state of blade damage. A contactless diagnostic system VDS-UT based on magneto-resistive sensors was developed in the Institute of Thermomechanics Academy of Sciences of the Czech Republic. The system provides on-line monitoring of vibration amplitudes and frequencies of all blades and notification of possible blade damage. Evaluation of the axial and circumferential components of the deflections by measuring the amplitude of blade impulse signals results in an overall improvement of the method. Using magneto-resistive sensors, blade elongation and untwisting can be determined as well.

  15. Barriers to Exercise in Younger and Older Non-Exercising Adult Women: A Cross Sectional Study in London, United Kingdom

    Science.gov (United States)

    Ansari, Walid El; Lovell, Geoff

    2009-01-01

    A survey of 100 women in the south of London, United Kingdom (UK) compared exercise barrier intensities between non-exercising younger (20–27 years) and older (28–35 years) adult women; and examined childcare duties as perceived barriers to exercise. Perceived barriers to exercise were examined using an Exercise Benefits/Barriers Scale (EBBS) comprising four subscales (exercise milieu; time expenditure; physical exertion; family discouragement). Participants’ number of children was also noted. Non-exercising older women reported significantly higher total exercise barriers, as well as across three barrier subscales: exercise milieu, time expenditure, and family discouragement. For both age groups, significant correlation existed between number of children and women’s total exercise barrier scores. Number of children explained ≈25% and ≈30% of the variance of younger and older women’s total barrier scores respectively. For both women groups, the strongest correlation between exercise barrier and number of children was for the time expenditure subscale. Broad grouping of 20–35 year old non-exercising women does not reflect a homogenous sample. Age categories employing narrower age brackets are recommended. Issues surrounding family responsibilities e.g. childcare duties may be shared between these groups and require further research and policy attention. PMID:19440527

  16. Barriers to Exercise in Younger and Older Non-Exercising Adult Women: A Cross Sectional Study in London, United Kingdom

    Directory of Open Access Journals (Sweden)

    Geoff Lovell

    2009-04-01

    Full Text Available A survey of 100 women in the south of London, United Kingdom (UK compared exercise barrier intensities between non-exercising younger (20-27 years and older (28-35 years adult women; and examined childcare duties as perceived barriers to exercise. Perceived barriers to exercise were examined using an Exercise Benefits/Barriers Scale (EBBS comprising four subscales (exercise milieu; time expenditure; physical exertion; family discouragement. Participants’ number of children was also noted. Non-exercising older women reported significantly higher total exercise barriers, as well as across three barrier subscales: exercise milieu, time expenditure, and family discouragement. For both age groups, significant correlation existed between number of children and women’s total exercise barrier scores. Number of children explained »25% and »30% of the variance of younger and older women’s total barrier scores respectively. For both women groups, the strongest correlation between exercise barrier and number of children was for the time expenditure subscale. Broad grouping of 20-35 year old non-exercising women does not reflect a homogenous sample. Age categories employing narrower age brackets are recommended. Issues surrounding family responsibilities e.g. childcare duties may be shared between these groups and require further research and policy attention.

  17. Barriers to exercise in younger and older non-exercising adult women: a cross sectional study in London, United Kingdom.

    Science.gov (United States)

    El Ansari, Walid; Lovell, Geoff

    2009-04-01

    A survey of 100 women in the south of London, United Kingdom (UK) compared exercise barrier intensities between non-exercising younger (20-27 years) and older (28-35 years) adult women; and examined childcare duties as perceived barriers to exercise. Perceived barriers to exercise were examined using an Exercise Benefits/Barriers Scale (EBBS) comprising four subscales (exercise milieu; time expenditure; physical exertion; family discouragement). Participants' number of children was also noted. Non-exercising older women reported significantly higher total exercise barriers, as well as across three barrier subscales: exercise milieu, time expenditure, and family discouragement. For both age groups, significant correlation existed between number of children and women's total exercise barrier scores. Number of children explained approximately 25% and approximately 30% of the variance of younger and older women's total barrier scores respectively. For both women groups, the strongest correlation between exercise barrier and number of children was for the time expenditure subscale. Broad grouping of 20-35 year old non-exercising women does not reflect a homogenous sample. Age categories employing narrower age brackets are recommended. Issues surrounding family responsibilities e.g. childcare duties may be shared between these groups and require further research and policy attention.

  18. Job burnout among critical care nurses from 14 adult intensive care units in northeastern China: a cross-sectional survey

    Science.gov (United States)

    Zhang, Xiao-Chun; Huang, De-Sheng; Guan, Peng

    2014-01-01

    Objectives The shortage of qualified nurses is one of the critical challenges in the field of healthcare. Among the contributing factors, job burnout has been indicated as a risk factor for the intention to leave. The purpose of this study was to provide a better understanding of the local status and reference data for coping strategies for intensive care unit (ICU)-nurse burnout among Liaoning ICU nurses. Design Observational study. Setting 17 ICUs from 10 tertiary-level hospitals in Liaoning, China. Participants 431 ICU nurses from 14 ICUs nested in 10 tertiary-level hospitals in Liaoning, China, were invited during October and November 2010. Primary measures Burnout was measured using the 22-item Chinese version of Maslach Burnout Inventory-Health Service Survey (MBI-HSS) questionnaires. Results 14 ICUs responded actively and were included; the response rate was 87.7% among the 486 invited participants from these 17 ICUs. The study population was a young population, with the median age 25 years, IQR 23–28 years and female nurses accounted for the major part (88.5%). 68 nurses (16%) were found to have a high degree of burnout, earning high emotional exhaustion and depersonalisation scores together with a low personal accomplishment score. Conclusions The present study indicated a moderate distribution of burnout among ICU nurses in Liaoning, China. An investigation into the burnout levels of this population could bring more attention to ICU caregivers. PMID:24948747

  19. High prevalence of diabetes among migrants in the United Arab Emirates using a cross-sectional survey.

    Science.gov (United States)

    Sulaiman, Nabil; Albadawi, Salah; Abusnana, Salah; Mairghani, Maisoon; Hussein, Amal; Al Awadi, Fatheya; Madani, Abdulrazak; Zimmet, Paul; Shaw, Jonathan

    2018-05-01

    In 2011, the United Arab Emirates (UAE) had the 10th highest diabetes prevalence globally, but this was based on data that excluded migrants who comprise 80% of the population. This study assessed diabetes prevalence across the UAE population. A random sample of migrants was recruited from the visa renewal centers. Data were collected using interviews, anthropometric measurements and fasting blood for glucose, lipids and genetic analyses. 2724 adults completed the questionnaires and blood tests. Of these, 81% were males, 65% were ≤40 years old and 3% were above 60 years. Diabetes, based on self-report or fasting plasma glucose ≥7.0 mmol/l, showed a crude prevalence of 15.5%, of whom 64.2% were newly diagnosed. Overall age- and sex-adjusted diabetes prevalence, according to the world mid-year population of 2013, was 19.1%. The highest prevalence was in Asians (16.4%) and non-Emirati Arabs (15.2%) and lowest in Africans and Europeans (11.9%). It increased with age: 6.3% in 18-30 years and 39.7% in 51 to 60 years. Lower education, obesity, positive family history, hypertension, dyslipidemia, snoring, and low HDL levels, all showed significant associations with diabetes. The high diabetes prevalence among migrants in the UAE, 64% of which was undiagnosed, necessitates urgent diabetes prevention and control programs for the entire UAE population.

  20. Damage detection of rotating wind turbine blades using local flexibility method and long-gauge fiber Bragg grating sensors

    Science.gov (United States)

    Hsu, Ting-Yu; Shiao, Shen-Yuan; Liao, Wen-I.

    2018-01-01

    Wind turbines are a cost-effective alternative energy source; however, their blades are susceptible to damage. Therefore, damage detection of wind turbine blades is of great importance for condition monitoring of wind turbines. Many vibration-based structural damage detection techniques have been proposed in the last two decades. The local flexibility method, which can determine local stiffness variations of beam-like structures by using measured modal parameters, is one of the most promising vibration-based approaches. The local flexibility method does not require a finite element model of the structure. A few structural modal parameters identified from the ambient vibration signals both before and after damage are required for this method. In this study, we propose a damage detection approach for rotating wind turbine blades using the local flexibility method based on the dynamic macro-strain signals measured by long-gauge fiber Bragg grating (FBG)-based sensors. A small wind turbine structure was constructed and excited using a shaking table to generate vibration signals. The structure was designed to have natural frequencies as close as possible to those of a typical 1.5 MW wind turbine in real scale. The optical fiber signal of the rotating blades was transmitted to the data acquisition system through a rotary joint fixed inside the hollow shaft of the wind turbine. Reversible damage was simulated by aluminum plates attached to some sections of the wind turbine blades. The damaged locations of the rotating blades were successfully detected using the proposed approach, with the extent of damage somewhat over-estimated. Nevertheless, although the specimen of wind turbine blades cannot represent a real one, the results still manifest that FBG-based macro-strain measurement has potential to be employed to obtain the modal parameters of the rotating wind turbines and then locations of wind turbine segments with a change of rigidity can be estimated effectively by

  1. The American Medical Association's Section on Surgery: The Beginnings of the Organization, Professionalization, and Specialization of Surgery in the United States.

    Science.gov (United States)

    Rutkow, Ira

    2017-01-01

    To explore the founding of the American Medical Association's Section on Surgery in 1859 and how it represented, on a national basis, the beginnings of organized surgery and the formal start of the professionalization and specialization of surgery in the United States. The broad social process of organization, professionalization, and specialization that began for various disciplines in America in the mid-19th century was a reaction to emerging economic, political, and scientific influences including industrialization, urbanization, and technology. For surgeons or, at least, those men who performed surgical operations, the efforts toward group organization provided a means to promote their skills and restrict competition. An analysis of the published literature, and unpublished documents relating to the creation of the American Medical Association's Section on Surgery. During the 1850s and through the 1870s, a time when surgery was still not considered a separate branch of medicine, the organization of the American Medical Association's Section on Surgery provided the much needed encouragement to surgeons in their quest for professional and specialty recognition. The establishment of the American Medical Association's Section on Surgery in 1859 helped shape the nationwide future of the craft, in particular, surgery's rise as a specialty and profession.

  2. A Cross-Sectional Study of Tobacco Advertising, Promotion, and Sponsorship in Airports across Europe and the United States

    Directory of Open Access Journals (Sweden)

    Andrea Soong

    2016-09-01

    Full Text Available Tobacco advertising, promotion, and sponsorship (TAPS bans are effective and are increasingly being implemented in a number of venues and countries, yet the state of TAPS in airports and their effect on airport smoking behavior is unknown. The objective of this study was to evaluate the presence of TAPS in airports across Europe and the US, and to begin to examine the relationship between TAPS and smoking behaviors in airports. We used a cross-sectional study design to observe 21 airports in Europe (11 and the US (10. Data collectors observed points of sale for tobacco products, types of products sold, advertisements and promotions, and branding or logos that appeared in the airport. Tobacco products were sold in 95% of all airports, with significantly more sales in Europe than the US. Advertisements appeared mostly in post-security areas; however, airports with advertisements in pre-security areas had significantly more smokers observed outdoors than airports without advertisements in pre-security areas. Tobacco branding appeared in designated smoking rooms as well as on non-tobacco products in duty free shops. TAPS are widespread in airports in Europe and the US and might be associated with outdoor smoking, though further research is needed to better understand any relationship between the two. This study adds to a growing body of research on tobacco control in air transit and related issues. As smoke-free policies advance, they should include comprehensive TAPS bans that extend to airport facilities.

  3. A Cross-Sectional Study of Tobacco Advertising, Promotion, and Sponsorship in Airports across Europe and the United States.

    Science.gov (United States)

    Soong, Andrea; Navas-Acien, Ana; Pang, Yuanjie; Lopez, Maria Jose; Garcia-Esquinas, Esther; Stillman, Frances A

    2016-09-28

    Tobacco advertising, promotion, and sponsorship (TAPS) bans are effective and are increasingly being implemented in a number of venues and countries, yet the state of TAPS in airports and their effect on airport smoking behavior is unknown. The objective of this study was to evaluate the presence of TAPS in airports across Europe and the US, and to begin to examine the relationship between TAPS and smoking behaviors in airports. We used a cross-sectional study design to observe 21 airports in Europe (11) and the US (10). Data collectors observed points of sale for tobacco products, types of products sold, advertisements and promotions, and branding or logos that appeared in the airport. Tobacco products were sold in 95% of all airports, with significantly more sales in Europe than the US. Advertisements appeared mostly in post-security areas; however, airports with advertisements in pre-security areas had significantly more smokers observed outdoors than airports without advertisements in pre-security areas. Tobacco branding appeared in designated smoking rooms as well as on non-tobacco products in duty free shops. TAPS are widespread in airports in Europe and the US and might be associated with outdoor smoking, though further research is needed to better understand any relationship between the two. This study adds to a growing body of research on tobacco control in air transit and related issues. As smoke-free policies advance, they should include comprehensive TAPS bans that extend to airport facilities.

  4. Preliminary Evaluation of the Section 1603 Treasury Grant Program for Renewable Power Projects in the United States

    Energy Technology Data Exchange (ETDEWEB)

    Bolinger, Mark; Wiser, Ryan; Darghouth, Naim

    2010-05-05

    This article evaluates the first year of the Section 1603 Treasury cash grant program, which enables renewable power projects in the U.S. to elect cash grants in lieu of the federal tax credits that are otherwise available. To date, the program has been heavily subscribed, particularly by wind power projects, which had received 86% of the nearly $2.6 billion in grants that had been disbursed as of March 1, 2010. As of that date, 6.2 GW of the 10 GW of new wind capacity installed in the U.S. in 2009 had applied for grants in lieu of production tax credits. Roughly 2.4 GW of this wind capacity may not have otherwise been built in 2009 absent the grant program; this 2.4 GW may have supported approximately 51,600 short-term full-time-equivalent (FTE) gross job-years in the U.S. during the construction phase of these wind projects, and 3,860 longterm FTE gross jobs during the operational phase. The program’s popularity stems from the significant economic value that it provides to renewable power projects, relative to the otherwise available tax credits. Although grants reward investment rather than efficient performance, this evaluation finds no evidence at this time of either widespread “gold-plating” or performance problems.

  5. Preliminary evaluation of the Section 1603 treasury grant program for renewable power projects in the United States

    International Nuclear Information System (INIS)

    Bolinger, Mark; Wiser, Ryan; Darghouth, Naim

    2010-01-01

    This article evaluates the first year of the Section 1603 Treasury cash grant program, which enables renewable power projects in the US to elect cash grants in lieu of the federal tax credits that are otherwise available. To date, the program has been heavily subscribed, particularly by wind power projects, which had received 86% of the nearly $2.6 billion in grants that had been disbursed as of March 1, 2010. As of that date, 6.2 GW of the 10 GW of new wind capacity installed in the US in 2009 had applied for grants in lieu of production tax credits. Roughly 2.4 GW of this wind capacity may not have otherwise been built in 2009 in the absence of the grant program; this 2.4 GW may have supported approximately 51,600 short-term full-time-equivalent (FTE) gross job-years in the US during the construction phase of these wind projects, and 3860 long-term FTE gross jobs during the operational phase. The program's popularity stems from the significant economic value that it provides to renewable power projects, relative to the otherwise available tax credits. Although grants reward investment rather than efficient performance, this evaluation finds no evidence at this time of either widespread 'gold-plating' or performance problems. (author)

  6. Use of Videoconferencing for Lactation Consultation: An Online Cross-Sectional Survey of Mothers' Acceptance in the United States.

    Science.gov (United States)

    Habibi, Mona F; Springer, Cary M; Spence, Marsha L; Hansen-Petrik, Melissa B; Kavanagh, Katherine F

    2018-05-01

    Suboptimal breastfeeding duration and exclusivity rates are a public health concern. Therefore, there is a need for identifying effective tools for use in interventions targeting specific barriers to optimal breastfeeding outcomes. Research aim: This study aimed to assess the relationship between acceptance of remote lactation consultation using videoconferencing and (a) maternal demographic factors, (b) technology acceptance subscales, (c) maternal learning style preferences, and (d) other potentially explanatory maternal factors. This was a cross-sectional, online study. English-speaking mothers of at least 18 years of age, with an infant age 4 months or younger, and who reported initiating breastfeeding were eligible to participate. Mothers were recruited from 27 randomly selected states. One hundred one mothers completed the survey, resulting in a response rate of 71%. The main outcome was acceptance of videoconferencing use for lactation consultation. No significant differences were found in acceptance by maternal demographic factors or learning style preferences. Acceptance was significantly related to perceived ease of use ( r = .680, p acceptance of videoconferencing for lactation consultation ( r = .432, p model ( R 2 = .616, p acceptance, maternal age was inversely related. This sample of mothers indicated general acceptance of videoconferencing for lactation consultation, with younger mothers and those perceiving it to be more useful demonstrating greater acceptance.

  7. 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...

  8. Blade runner. Blade server and virtualization technology can help hospitals save money--but they are far from silver bullets.

    Science.gov (United States)

    Lawrence, Daphne

    2009-03-01

    Blade servers and virtualization can reduce infrastructure, maintenance, heating, electric, cooling and equipment costs. Blade server technology is evolving and some elements may become obsolete. There is very little interoperability between blades. Hospitals can virtualize 40 to 60 percent of their servers, and old servers can be reused for testing. Not all applications lend themselves to virtualization--especially those with high memory requirements. CIOs should engage their vendors in virtualization discussions.

  9. 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.

  10. Inverse Association between Diabetes and Altitude: A Cross Sectional Study in the Adult Population of the United States

    Science.gov (United States)

    Woolcott, Orison O.; Castillo, Oscar A.; Gutierrez, Cesar; Elashoff, Robert M.; Stefanovski, Darko; Bergman, Richard N.

    2014-01-01

    Objective To determine whether geographical elevation is inversely associated with diabetes, while adjusting for multiple risk factors. Design and Methods This is a cross-sectional analysis of publicly available online data from the Behavioral Risk Factor Surveillance System, 2009. Final dataset included 285,196 US adult subjects. Odds ratios were obtained from multilevel mixed-effects logistic regression analysis. Results Among US adults (≥20 years old), the odds ratio for diabetes were 1.00 between 0−499 m of altitude (reference), 0.95 (95% confidence interval, 0.90 to 1.01) between 500−1,499 m, and 0.88 (0.81 to 0.96) between 1,500−3,500 m, adjusting for age, sex, body mass index, ethnicity, self-reported fruit and vegetable consumption, self-reported physical activity, current smoking status, level of education, income, health status, employment status, and county-level information on migration rate, urbanization, and latitude. The inverse association between altitude and diabetes in the US was found among men [0.84 (0.76 to 0.94)], but not women [1.09 (0.97 to 1.22)]. Conclusions Among US adults, living at high altitude (1,500−3,500 m) is associated with lower odds of having diabetes than living between 0−499 m, while adjusting for multiple risk factors. Our findings suggest that geographical elevation may be an important factor linked to diabetes. PMID:24890677

  11. The SNL100-03 Blade: Design Studies with Flatback Airfoils for the Sandia 100-meter Blade.

    Energy Technology Data Exchange (ETDEWEB)

    Griffith, Daniel; Richards, Phillip William

    2014-09-01

    A series of design studies were performed to inv estigate the effects of flatback airfoils on blade performance and weight for large blades using the Sandi a 100-meter blade designs as a starting point. As part of the study, the effects of varying the blade slenderness on blade structural performance was investigated. The advantages and disadvantages of blad e slenderness with respect to tip deflection, flap- wise & edge-wise fatigue resistance, panel buckling capacity, flutter speed, manufacturing labor content, blade total weight, and aerodynamic design load magn itude are quantified. Following these design studies, a final blade design (SNL100-03) was prod uced, which was based on a highly slender design using flatback airfoils. The SNL100-03 design with flatback airfoils has weight of 49 tons, which is about 16% decrease from its SNL100-02 predecessor that used conventional sharp trailing edge airfoils. Although not systematically optimized, the SNL100 -03 design study provides an assessment of and insight into the benefits of flatback airfoils for la rge blades as well as insights into the limits or negative consequences of high blade slenderness resulting from a highly slender SNL100-03 planform as was chosen in the final design definition. This docum ent also provides a description of the final SNL100-03 design definition and is intended to be a companion document to the distribution of the NuMAD blade model files for SNL100-03, which are made publicly available. A summary of the major findings of the Sandia 100-meter blade development program, from the initial SNL100-00 baseline blade through the fourth SNL100-03 blade study, is provided. This summary includes the major findings and outcomes of blade d esign studies, pathways to mitigate the identified large blade design drivers, and tool development that were produced over the course of this five-year research program. A summary of large blade tec hnology needs and research opportunities is also presented.

  12. Numerical simulation on a straight-bladed vertical axis wind turbine with auxiliary blade

    Science.gov (United States)

    Li, Y.; Zheng, Y. F.; Feng, F.; He, Q. B.; Wang, N. X.

    2016-08-01

    To improve the starting performance of the straight-bladed vertical axis wind turbine (SB-VAWT) at low wind speed, and the output characteristics at high wind speed, a flexible, scalable auxiliary vane mechanism was designed and installed into the rotor of SB-VAWT in this study. This new vertical axis wind turbine is a kind of lift-to-drag combination wind turbine. The flexible blade expanded, and the driving force of the wind turbines comes mainly from drag at low rotational speed. On the other hand, the flexible blade is retracted at higher speed, and the driving force is primarily from a lift. To research the effects of the flexible, scalable auxiliary module on the performance of SB-VAWT and to find its best parameters, the computational fluid dynamics (CFD) numerical calculation was carried out. The calculation result shows that the flexible, scalable blades can automatic expand and retract with the rotational speed. The moment coefficient at low tip speed ratio increased substantially. Meanwhile, the moment coefficient has also been improved at high tip speed ratios in certain ranges.

  13. 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...

  14. Smart actuation mechanisms for helicopter blades: design case for a mach-scaled model blade

    NARCIS (Netherlands)

    Paternoster, Alexandre

    2013-01-01

    This work is part of the European project “Clean Sky”, which aims at improving the efficiency and the global transport quality of aircraft. The research, in this project, is currently focussing on active flap systems for helicopters to adapt the blade aerodynamic properties to local aerodynamic

  15. Development of a novel walkability index for London, United Kingdom: cross-sectional application to the Whitehall II Study

    Directory of Open Access Journals (Sweden)

    Jemima C. Stockton

    2016-05-01

    Full Text Available Abstract Background Physical activity is essential for health; walking is the easiest way to incorporate activity into everyday life. Previous studies report positive associations between neighbourhood walkability and walking but most focused on cities in North America and Australasia. Urban form with respect to street connectivity, residential density and land use mix—common components of walkability indices—differs in European cities. The objective of this study was to develop a walkability index for London and test the index using walking data from the Whitehall II Study.  Methods A neighbourhood walkability index for London was constructed, comprising factors associated with walking behaviours: residential dwelling density, street connectivity and land use mix. Three models were produced that differed in the land uses included. Neighbourhoods were operationalised at three levels of administrative geography: (i 21,140 output areas, (ii 633 wards and (iii 33 local authorities. A neighbourhood walkability score was assigned to each London-dwelling Whitehall II Study participant (2003–04, N = 3020, mean ± SD age = 61.0 years ± 6.0 based on residential postcode. The effect of changing the model specification and the units of enumeration on spatial variation in walkability was examined. Results There was a radial decay in walkability from the centre to the periphery of London. There was high inter-model correlation in walkability scores for any given neighbourhood operationalisation (0.92–0.98, and moderate-high correlation between neighbourhood operationalisations for any given model (0.39–0.70. After adjustment for individual level factors and area deprivation, individuals in the most walkable neighbourhoods operationalised as wards were more likely to walk >6 h/week (OR = 1.4; 95 % CI: 1.1–1.9 than those in the least walkable. Conclusions Walkability was associated with walking time in adults. This

  16. Development of a novel walkability index for London, United Kingdom: cross-sectional application to the Whitehall II Study.

    Science.gov (United States)

    Stockton, Jemima C; Duke-Williams, Oliver; Stamatakis, Emmanuel; Mindell, Jennifer S; Brunner, Eric J; Shelton, Nicola J

    2016-05-18

    Physical activity is essential for health; walking is the easiest way to incorporate activity into everyday life. Previous studies report positive associations between neighbourhood walkability and walking but most focused on cities in North America and Australasia. Urban form with respect to street connectivity, residential density and land use mix-common components of walkability indices-differs in European cities. The objective of this study was to develop a walkability index for London and test the index using walking data from the Whitehall II Study. A neighbourhood walkability index for London was constructed, comprising factors associated with walking behaviours: residential dwelling density, street connectivity and land use mix. Three models were produced that differed in the land uses included. Neighbourhoods were operationalised at three levels of administrative geography: (i) 21,140 output areas, (ii) 633 wards and (iii) 33 local authorities. A neighbourhood walkability score was assigned to each London-dwelling Whitehall II Study participant (2003-04, N = 3020, mean ± SD age = 61.0 years ± 6.0) based on residential postcode. The effect of changing the model specification and the units of enumeration on spatial variation in walkability was examined. There was a radial decay in walkability from the centre to the periphery of London. There was high inter-model correlation in walkability scores for any given neighbourhood operationalisation (0.92-0.98), and moderate-high correlation between neighbourhood operationalisations for any given model (0.39-0.70). After adjustment for individual level factors and area deprivation, individuals in the most walkable neighbourhoods operationalised as wards were more likely to walk >6 h/week (OR = 1.4; 95 % CI: 1.1-1.9) than those in the least walkable. Walkability was associated with walking time in adults. This walkability index could help urban planners identify and design neighbourhoods in

  17. Blade Vibration Measurement System for Characterization of Closely Spaced Modes and Mistuning, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — There are several ongoing challenges in non-contacting blade vibration and stress measurement systems that can address closely spaced modes and blade-to-blade...

  18. Noise from Two-Blade Propellers

    Science.gov (United States)

    Stowell, E Z; Deming, A F

    1936-01-01

    The two-blade propeller, one of the most powerful sources of sound known, has been studied with the view of obtaining fundamental information concerning the noise emission. In order to eliminate engine noise, the propeller was mounted on an electric motor. A microphone was used to pick up the sound whose characteristics were studied electrically. The distribution of noise throughout the frequency range, as well as the spatial distribution about the propeller, was studied. The results are given in the form of polar diagrams. An appendix of common acoustical terms is included.

  19. Shape Optimization of Wind Turbine Blades

    DEFF Research Database (Denmark)

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

    2009-01-01

    of the rotor. The design variables used in the current study are the blade shape parameters, including chord, twist and relative thickness. To validate the implementation of the aerodynamic/aero-elastic model, the computed aerodynamic results are compared to experimental data for the experimental rotor used...... in the European Commision-sponsored project Model Experiments in Controlled Conditions, (MEXICO) and the computed aero-elastic results are examined against the FLEX code for flow post the Tjereborg 2 MW rotor. To illustrate the optimization technique, three wind turbine rotors of different sizes (the MEXICO 25 k...

  20. Atmospheric Plasma Blade for Surgical Purposes

    Science.gov (United States)

    Oksuz, Lutfi; Yurdabak Karaca, Gozde; Özkaptan, Emir; Uygun, Emre; Uygun Oksuz, Aysegul

    2017-10-01

    Atmospheric plasma cut is a process at the minimum level due to the ions, radicals and free electrons generated by the active electrode and target tissue. Atmospheric plasma cutting devices provide significant advantages as a non-contact electrocautery system that can operate in isotonic environment. During operations where plasma cutting is applied, bleeding is controlled and the side effects that would create the isotonic environment are eliminated. In this study in vivo and in vitro studies will be carried out by producing and optimizing the atmospheric plasma blade. Once the optimum parameters of the instrument are determined, in vivo studies will be performed and the pathology results will be evaluated.

  1. Standard practice for examination of fiberglass reinforced plastic fan blades using acoustic emission

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This practice provides guidelines for acoustic emission (AE) examinations of fiberglass reinforced plastic (FRP) fan blades of the type used in industrial cooling towers and heat exchangers. 1.2 This practice uses simulated service loading to determine structural integrity. 1.3 This practice will detect sources of acoustic emission in areas of sensor coverage that are stressed during the course of the examination. 1.4 This practice applies to examinations of new and in-service fan blades. 1.5 This practice is limited to fan blades of FRP construction, with length (hub centerline to tip) of less than 3 m [10 ft], and with fiberglass content greater than 15 % by weight. 1.6 AE measurements are used to detect emission sources. Other nondestructive examination (NDE) methods may be used to evaluate the significance of AE sources. Procedures for other NDE methods are beyond the scope of this practice. 1.7 Units—The values stated in either SI units or inch-pound units are to be regarded separately as sta...

  2. Blade Profile Optimization of Kaplan Turbine Using CFD Analysis

    Directory of Open Access Journals (Sweden)

    Aijaz Bashir Janjua

    2013-10-01

    Full Text Available Utilization of hydro-power as renewable energy source is of prime importance in the world now. Hydropower energy is available in abundant in form of falls, canals rivers, dams etc. It means, there are various types of sites with different parameters like flow rate, heads, etc. Depending upon the sites, water turbines are designed and manufactured to avail hydro-power energy. Low head turbines on runof-river are widely used for the purpose. Low head turbines are classified as reaction turbines. For runof river, depending upon the variety of site data, low head Kaplan turbines are selected, designed and manufactured. For any given site requirement, it becomes very essential to design the turbine runner blades through optimization of the CAD model of blades profile. This paper presents the optimization technique carried out on a complex geometry of blade profile through static and dynamic computational analysis. It is used through change of the blade profile geometry at five different angles in the 3D (Three Dimensional CAD model. Blade complex geometry and design have been developed by using the coordinates point system on the blade in PRO-E /CREO software. Five different blade models are developed for analysis purpose. Based on the flow rate and heads, blade profiles are analyzed using ANSYS software to check and compare the output results for optimization of the blades for improved results which show that by changing blade profile angle and its geometry, different blade sizes and geometry can be optimized using the computational techniques with changes in CAD models.

  3. Blade profile optimization of kaplan turbine using cfd analysis

    International Nuclear Information System (INIS)

    Janjua, A.B.; Khalil, M.S.

    2013-01-01

    Utilization of hydro-power as renewable energy source is of prime importance in the world now. Hydropower energy is available in abundant in form of falls, canals rivers, dams etc. It means, there are various types of sites with different parameters like flow rate, heads, etc. Depending upon the sites, water turbines are designed and manufactured to avail hydro-power energy. Low head turbines on runof-river are widely used for the purpose. Low head turbines are classified as reaction turbines. For runof-river, depending upon the variety of site data, low head Kaplan turbines are selected, designed and manufactured. For any given site requirement, it becomes very essential to design the turbine runner blades through optimization of the CAD model of blades profile. This paper presents the optimization technique carried out on a complex geometry of blade profile through static and dynamic computational analysis. It is used through change of the blade profile geometry at five different angles in the 3D (Three Dimensional) CAD model. Blade complex geometry and design have been developed by using the coordinates point system on the blade in PRO-E /CREO software. Five different blade models are developed for analysis purpose. Based on the flow rate and heads, blade profiles are analyzed using ANSYS software to check and compare the output results for optimization of the blades for improved results which show that by changing blade profile angle and its geometry, different blade sizes and geometry can be optimized using the computational techniques with changes in CAD models. (author)

  4. Active Blade Vibration Control Being Developed and Tested

    Science.gov (United States)

    Johnson, Dexter

    2003-01-01

    Gas turbine engines are currently being designed to have increased performance, lower weight and manufacturing costs, and higher reliability. Consequently, turbomachinery components, such as turbine and compressor blades, have designs that are susceptible to new vibration problems and eventual in-service failure due to high-cycle fatigue. To address this problem, researchers at the NASA Glenn Research Center are developing and testing innovative active blade vibration control concepts. Preliminary results of using an active blade vibration control system, involving a rotor supported by an active magnetic bearing in Glenn's Dynamic Spin Rig, indicate promising results (see the photograph). Active blade vibration control was achieved using feedback of blade strain gauge signals within the magnetic bearing control loop. The vibration amplitude was reduced substantially (see the graphs). Also, vibration amplitude amplification was demonstrated; this could be used to enhance structural mode identification, if desired. These results were for a nonrotating two-bladed disk. Tests for rotating blades are planned. Current and future active blade vibration control research is planned to use a fully magnetically suspended rotor and smart materials. For the fully magnetically suspended rotor work, three magnetic bearings (two radial and one axial) will be used as actuators instead of one magnetic bearing. This will allow additional degrees of freedom to be used for control. For the smart materials work, control effectors located on and off the blade will be considered. Piezoelectric materials will be considered for on-the-blade actuation, and actuator placement on a stator vane, or other nearby structure, will be investigated for off-the-blade actuation. Initial work will focus on determining the feasibility of these methods by performing basic analysis and simple experiments involving feedback control.

  5. Bimetallic Blisks with Shrouded Turbine Blades for Gas Turbine Engines

    Directory of Open Access Journals (Sweden)

    L. A. Magerramova

    2015-01-01

    Full Text Available The paper discusses prospects of using blisks with shrouded blades. Increasing an engine life and efficiency as well as mass reduction can also be achieved by increasing blade numbers and decreasing disk diameter. But design engineers are faced with the problem of blade placement because of the disk size and root dimensions.The problem of increasing life and cyclic durability, vibration strength, and lightweight design of the turbine gas turbine wheels, can be solved by an elimination of blade - disk locks.The technology of manufacturing one-piece blisks by connecting the blades with the disc part using hot isostatic pressing was developed. This technology allows us to use blades with shrouds. It is necessary to increase efficiency and to improve high cycle fatigue performance of rotor blades.One of the pressing problems is to ensure the necessary position of shrouds in relation to each other in the manufacturing process as well as in the service. Numerical studies of the influence of the shroud mounting position on blade strength during operation allowed us to develop a methodology of choosing a shroud mounting position.Based on the two turbine wheels (LPT and HPT calculations advantages of blisk design with respect to the lock-based design were shown. Application of bimetallic blisks with shrouded blades resulted in a lifespan increase and weight reduction.In addition, other advantages of blisk design are as follows: possible reduction in the number of parts, elimination of leaks and fretting that take place in the blade - disk locks, exception of expensive broaching operations and disk alloy saving. The shortcoming is elimination of damping in root connection. In addition, there are no widely used repair methods.Despite these disadvantages the usage of bimetallic turbine blisks with shrouded blades is very promising.

  6. A Cross-Sectional Survey of Near-Infrared Spectroscopy Use in Pediatric Cardiac ICUs in the United Kingdom, Ireland, Italy, and Germany.

    Science.gov (United States)

    Hoskote, Aparna U; Tume, Lyvonne N; Trieschmann, Uwe; Menzel, Christoph; Cogo, Paola; Brown, Katherine L; Broadhead, Michael W

    2016-01-01

    Despite the increasing use of near-infrared spectroscopy across pediatric cardiac ICUs, there is significant variability and equipoise with no universally accepted management algorithms. We aimed to explore the use of near-infrared spectroscopy in pediatric cardiac ICUs in the United Kingdom, Ireland, Italy, and Germany. A cross-sectional multicenter, multinational electronic survey of one consultant in each pediatric cardiac ICU. Pediatric cardiac ICUs in the United Kingdom and Ireland (n = 13), Italy (n = 12), and Germany (n = 33). Questionnaire targeted to establish use, targets, protocols/thresholds for intervention, and perceived usefulness of near-infrared spectroscopy monitoring. Overall, 42 of 58 pediatric cardiac ICUs (72%) responded: United Kingdom and Ireland, 11 of 13 (84.6%); Italy, 12 of 12 (100%); and Germany, 19 of 33 (57%, included all major centers). Near-infrared spectroscopy usage varied with 35% (15/42) reporting that near-infrared spectroscopy was not used at all (7/42) or occasionally (8/42); near-infrared spectroscopy use was much less common in the United Kingdom (46%) when compared with 78% in Germany and all (100%) in Italy. Only four units had a near-infrared spectroscopy protocol, and 18 specifically used near-infrared spectroscopy in high-risk patients; 37 respondents believed that near-infrared spectroscopy added value to standard monitoring and 23 believed that it gave an earlier indication of deterioration, but only 19 would respond based on near-infrared spectroscopy data alone. Targets for absolute values and critical thresholds for intervention varied widely between units. The reasons cited for not or occasionally using near-infrared spectroscopy were expense (n = 6), limited evidence and uncertainty on how it guides management (n = 4), difficulty in interpretation, and unreliability of data (n = 3). Amongst the regular or occasional near-infrared spectroscopy users (n = 35), 28 (66%) agreed that a multicenter study is warranted

  7. A cross sectional study of surgical training among United Kingdom general practitioners with specialist interests in surgery.

    Science.gov (United States)

    Ferguson, H J M; Fitzgerald, J E F; Reilly, J; Beamish, A J; Gokani, V J

    2015-04-08

    Increasing numbers of minor surgical procedures are being performed in the community. In the UK, general practitioners (family medicine physicians) with a specialist interest (GPwSI) in surgery frequently undertake them. This shift has caused decreases in available cases for junior surgeons to gain and consolidate operative skills. This study evaluated GPwSI's case-load, procedural training and perceptions of offering formalised operative training experience to surgical trainees. Prospective, questionnaire-based cross-sectional study. A novel, 13-item, self-administered questionnaire was distributed to members of the Association of Surgeons in Primary Care (ASPC). A total 113 of 120 ASPC members completed the questionnaire, representing a 94% response rate. Respondents were general practitioners practising or intending to practice surgery in the community. Respondents performed a mean of 38 (range 5-150) surgical procedures per month in primary care. 37% (42/113) of respondents had previously been awarded Membership or Fellowship of a Surgical Royal College; 22% (25/113) had completed a surgical certificate or diploma or undertaken a course of less than 1 year duration. 41% (46/113) had no formal British surgical qualifications. All respondents believed that surgical training in primary care could be valuable for surgical trainees, and the majority (71/113, 63%) felt that both general practice and surgical trainees could benefit equally from such training. There is a significant volume of surgical procedures being undertaken in the community by general practitioners, with the capacity and appetite for training of prospective surgeons in this setting, providing appropriate standards are achieved and maintained, commensurate with current standards in secondary care. Surgical experience and training of GPwSI's in surgery is highly varied, and does not yet benefit from the quality assurance secondary care surgical training in the UK undergoes. The Royal Colleges of

  8. Effect of technological deviation on aerodynamic efficiency of reaction blades of steam and gas turbines at high Mach nos

    International Nuclear Information System (INIS)

    Husain, Z.

    1991-01-01

    During manufacture and assembly of steam and gas turbine blades there are always some technological deviation and is meant local increase or decrease in dimension at certain sections of the profile improper stagger angle of long blades during assembly etc. In this paper the effect of oversize in dimensions at certain important places along a reaction profile has been studied. The technological deviation has been made by sticking thin aluminium foils of 0.3 mm thickness and 15 mm width at inlet and exit tips of reactive profiles and its effect on aerodynamic efficiency at mach. nos ranging from 0.7 to 1.1. The object of performing these tests was to obtain comprehensive data based on which information suitable tolerances could be recommended during manufacture of these blades

  9. Wind turbine blades: A study of prototypes in a steady regime - Unsteady considerations

    Science.gov (United States)

    Leblanc, R.; Goethals, R.; de Saint Louvent, B.

    1981-11-01

    The results of comparisons of numerical models with experimental results for the performance of prototype wind turbines in steady flows are presented, along with preliminary results on behavior in unsteady flows. The numerical models are based on previous schemes devised for propellers, with modifications for small perturbations, significant radial velocity effects from the wake, and the fact that the speed is induced. Two computational methods are currently used, one a method of short blades, the other the Prandtl lifting line theory. Trials have been run in the T4 wind tunnel using a 3 m horizontal axis machine and a 2.5 m Darrieus. Attention is given to modeling the structural dynamics and turbulent flow structures encountered by wind turbines. Experimental results relating windspeed, angle of attack, and output are presented. Optimization studies have indicated that wind farms will require a 6-7 blade diameter unit spacing to maintain satisfactory group output efficiencies.

  10. Nonlinear aeroelastic modelling for wind turbine blades based on blade element momentum theory and geometrically exact beam theory

    International Nuclear Information System (INIS)

    Wang, Lin; Liu, Xiongwei; Renevier, Nathalie; Stables, Matthew; Hall, George M.

    2014-01-01

    Due to the increasing size and flexibility of large wind turbine blades, accurate and reliable aeroelastic modelling is playing an important role for the design of large wind turbines. Most existing aeroelastic models are linear models based on assumption of small blade deflections. This assumption is not valid anymore for very flexible blade design because such blades often experience large deflections. In this paper, a novel nonlinear aeroelastic model for large wind turbine blades has been developed by combining BEM (blade element momentum) theory and mixed-form formulation of GEBT (geometrically exact beam theory). The nonlinear aeroelastic model takes account of large blade deflections and thus greatly improves the accuracy of aeroelastic analysis of wind turbine blades. The nonlinear aeroelastic model is implemented in COMSOL Multiphysics and validated with a series of benchmark calculation tests. The results show that good agreement is achieved when compared with experimental data, and its capability of handling large deflections is demonstrated. Finally the nonlinear aeroelastic model is applied to aeroelastic modelling of the parked WindPACT 1.5 MW baseline wind turbine, and reduced flapwise deflection from the nonlinear aeroelastic model is observed compared to the linear aeroelastic code FAST (Fatigue, Aerodynamics, Structures, and Turbulence). - Highlights: • A novel nonlinear aeroelastic model for wind turbine blades is developed. • The model takes account of large blade deflections and geometric nonlinearities. • The model is reliable and efficient for aeroelastic modelling of wind turbine blades. • The accuracy of the model is verified by a series of benchmark calculation tests. • The model provides more realistic aeroelastic modelling than FAST (Fatigue, Aerodynamics, Structures, and Turbulence)

  11. Bacterial contamination of re-usable laryngoscope blades during the ...

    African Journals Online (AJOL)

    We aimed to assess the level of microbial contamination of re-usable laryngoscope blades at a public hospital in South Africa. Setting. The theatre complex of a secondary-level public hospital in Johannesburg. Methods. Blades from two different theatres were sampled twice daily, using a standardised technique, over a ...

  12. Force Measurements on a VAWT Blade in Parked Conditions

    Directory of Open Access Journals (Sweden)

    Anders Goude

    2017-11-01

    Full Text Available The forces on a turbine at extreme wind conditions when the turbine is parked is one of the most important design cases for the survivability of a turbine. In this work, the forces on a blade and its support arms have been measured on a 12 kW straight-bladed vertical axis wind turbine at an open site. Two cases are tested: one during electrical braking of the turbine, which allows it to rotate slowly, and one with the turbine mechanically fixed with the leading edge of the blade facing the main wind direction. The force variations with respect to wind direction are investigated, and it is seen that significant variations in forces depend on the wind direction. The measurements show that for the fixed case, when subjected to the same wind speed, the forces are lower when the blade faces the wind direction. The results also show that due to the lower forces at this particular wind direction, the average forces for the fixed blade are notably lower. Hence, it is possible to reduce the forces on a turbine blade, simply by taking the dominating wind direction into account when the turbine is parked. The measurements also show that a positive torque is generated from the blade for most wind directions, which causes the turbine to rotate in the electrically-braked case. These rotations will cause increased fatigue loads on the turbine blade.

  13. Aeroelastic multidisciplinary design optimization of a swept wind turbine blade

    DEFF Research Database (Denmark)

    Pavese, Christian; Tibaldi, Carlo; Zahle, Frederik

    2017-01-01

    Mitigating loads on a wind turbine rotor can reduce the cost of energy. Sweeping blades produces a structural coupling between flapwise bending and torsion, which can be used for load alleviation purposes. A multidisciplinary design optimization (MDO) problem is formulated including the blade sweep...

  14. Damage detection in wind turbine blades using acoustic techniques

    Energy Technology Data Exchange (ETDEWEB)

    Juengert, A., E-mail: anne.juengert@mpa.uni-stuttgart.de [Univ. of Stuttgart, Materialpruefungsanstalt Stuttgart, Stuttgart (Germany)

    2013-05-15

    Facing climate change, the use of renewable energy gains importance. The wind energy sector grows very fast. Bigger and more powerful wind turbines will be built in the coming decades and the safety and reliability of the turbines will become more important. Wind turbine blades have to be inspected at regular intervals, because they are highly stressed during operation and a blade breakdown can cause big economic damages. The turbine blades consist of fiber reinforced plastics (GFRP/CFRP) and sandwich areas containing wood or plastic foam. The blades are manufactured as two halves and glued together afterwards. Typical damages are delaminations within the GFRP or the sandwich and missing adhesive or deficient bond at the bonding surfaces. The regular inspections of wind turbine blades are performed manually by experts and are limited to visual appraisals and simple tapping tests. To improve the inspections of wind turbine blades non-destructive testing techniques using acoustic waves are being developed. To detect delaminations within the laminates of the turbine blade, a local resonance spectroscopy was used. To detect missing bond areas from the outside of the blade the impulse-echo-technique was applied. This paper is an updated reprint of an article published on ndt.net in 2008. (author)

  15. A Critical Review of Future Materials for Wind Turbine Blades

    DEFF Research Database (Denmark)

    Raghavalu Thirumalai, Durai Prabhakaran

    2014-01-01

    Wind turbine industry is continuously evaluating materials systems to replace the current thermoset composite technologies. Since turbine blades are the key component in the wind turbines and the size of the blade is increasing in todays wind design, the materials selection has become crucial...

  16. Future Materials for Wind Turbine Blades - A Critical Review

    DEFF Research Database (Denmark)

    Raghavalu Thirumalai, Durai Prabhakaran

    2012-01-01

    Wind turbine industry is continuously evaluating material systems to replace the current thermoset composite technologies. Since turbine blades are the key component in the wind turbines and the size of the blade is increasing in today’s wind design, the material selection has become crucial...

  17. Implicit geometric representations for optimal design of gas turbine blades

    International Nuclear Information System (INIS)

    Mansour, T.; Ghaly, W.

    2004-01-01

    Shape optimization requires a proper geometric representation of the blade profile; the parameters of such a representation are usually taken as design variables in the optimization process. This implies that the model must possess three specific features: flexibility, efficiency, and accuracy. For the specific task of aerodynamic optimization for turbine blades, it is critical to have flexibility in both the global and local design spaces in order to obtain a successful optimization. This work is concerned with the development of two geometric representations of turbine blade profiles that are appropriate for aerodynamic optimization: the Modified Rapid Axial Turbine Design (MRATD) model where the blade is represented by five low-order curves that satisfy eleven designer parameters; this model is suitable for a global search of the design space. The second model is NURBS parameterization of the blade profile that can be used for a local refinement. The two models are presented and are assessed for flexibility and accuracy when representing several typical turbine blade profiles. The models will be further discussed in terms of curve smoothness and blade shape representation with a multi-NURBS curve versus one curve and its effect on the flow field, in particular the pressure distribution along the blade surfaces, will be elaborated. (author)

  18. Vibration-based SHM System: Application to Wind Turbine Blades

    DEFF Research Database (Denmark)

    Tcherniak, D.; Mølgaard, Lasse Lohilahti

    2015-01-01

    propagate along the blade and are measured by an array of accelerometers. Unsupervised learning is applied to the data: the vibration patterns corresponding to the undamaged blade are used to create a statistical model of the reference state. During the detection stage, the current vibration pattern...

  19. Computational Fluid Dynamic Analysis of a Vibrating Turbine Blade

    Directory of Open Access Journals (Sweden)

    Osama N. Alshroof

    2012-01-01

    Full Text Available This study presents the numerical fluid-structure interaction (FSI modelling of a vibrating turbine blade using the commercial software ANSYS-12.1. The study has two major aims: (i discussion of the current state of the art of modelling FSI in gas turbine engines and (ii development of a “tuned” one-way FSI model of a vibrating turbine blade to investigate the correlation between the pressure at the turbine casing surface and the vibrating blade motion. Firstly, the feasibility of the complete FSI coupled two-way, three-dimensional modelling of a turbine blade undergoing vibration using current commercial software is discussed. Various modelling simplifications, which reduce the full coupling between the fluid and structural domains, are then presented. The one-way FSI model of the vibrating turbine blade is introduced, which has the computational efficiency of a moving boundary CFD model. This one-way FSI model includes the corrected motion of the vibrating turbine blade under given engine flow conditions. This one-way FSI model is used to interrogate the pressure around a vibrating gas turbine blade. The results obtained show that the pressure distribution at the casing surface does not differ significantly, in its general form, from the pressure at the vibrating rotor blade tip.

  20. 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.

  1. 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.

  2. Damage detection in wind turbine blades using acoustic techniques

    International Nuclear Information System (INIS)

    Juengert, A.

    2013-01-01

    Facing climate change, the use of renewable energy gains importance. The wind energy sector grows very fast. Bigger and more powerful wind turbines will be built in the coming decades and the safety and reliability of the turbines will become more important. Wind turbine blades have to be inspected at regular intervals, because they are highly stressed during operation and a blade breakdown can cause big economic damages. The turbine blades consist of fiber reinforced plastics (GFRP/CFRP) and sandwich areas containing wood or plastic foam. The blades are manufactured as two halves and glued together afterwards. Typical damages are delaminations within the GFRP or the sandwich and missing adhesive or deficient bond at the bonding surfaces. The regular inspections of wind turbine blades are performed manually by experts and are limited to visual appraisals and simple tapping tests. To improve the inspections of wind turbine blades non-destructive testing techniques using acoustic waves are being developed. To detect delaminations within the laminates of the turbine blade, a local resonance spectroscopy was used. To detect missing bond areas from the outside of the blade the impulse-echo-technique was applied. This paper is an updated reprint of an article published on ndt.net in 2008. (author)

  3. 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)

  4. Vortex dynamics during blade-vortex interactions

    Science.gov (United States)

    Peng, Di; Gregory, James W.

    2015-05-01

    Vortex dynamics during parallel blade-vortex interactions (BVIs) were investigated in a subsonic wind tunnel using particle image velocimetry (PIV). Vortices were generated by applying a rapid pitch-up motion to an airfoil through a pneumatic system, and the subsequent interactions with a downstream, unloaded target airfoil were studied. The blade-vortex interactions may be classified into three categories in terms of vortex behavior: close interaction, very close interaction, and collision. For each type of interaction, the vortex trajectory and strength variation were obtained from phase-averaged PIV data. The PIV results revealed the mechanisms of vortex decay and the effects of several key parameters on vortex dynamics, including separation distance (h/c), Reynolds number, and vortex sense. Generally, BVI has two main stages: interaction between vortex and leading edge (vortex-LE interaction) and interaction between vortex and boundary layer (vortex-BL interaction). Vortex-LE interaction, with its small separation distance, is dominated by inviscid decay of vortex strength due to pressure gradients near the leading edge. Therefore, the decay rate is determined by separation distance and vortex strength, but it is relatively insensitive to Reynolds number. Vortex-LE interaction will become a viscous-type interaction if there is enough separation distance. Vortex-BL interaction is inherently dominated by viscous effects, so the decay rate is dependent on Reynolds number. Vortex sense also has great impact on vortex-BL interaction because it changes the velocity field and shear stress near the surface.

  5. Condensation phenomena in a turbine blade passage

    International Nuclear Information System (INIS)

    Skillings, S.A.

    1989-02-01

    The mechanisms associated with the formation and growth of water droplets in the large low-pressure (LP) turbines used for electrical power generation are poorly understood and recent measurements have indicated that an unusually high loss is associated with the initial nucleation of these droplets. In order to gain an insight into the phenomena which arise in the turbine situation, some experiments were performed to investigate the behaviour of condensing steam flows in a blade passage. This study has revealed the fundamental significance of droplet nucleation in modifying the single-phase flow structure and results are presented which show the change in shock wave pattern when inlet superheat and outlet Mach number are varied. The trailing-edge shock wave structure appears considerably more robust towards variation of inlet superheat than purely one-dimensional considerations may suggest and the inadequacies of adopting a one-dimensional theory to analyse multi-dimensional condensing flows are demonstrated. Over a certain range of outlet Mach numbers an oscillating shock wave will establish in the throat region of the blade passage and this has been shown to interact strongly with droplet nucleation, resulting in a considerably increased mean droplet size. The possible implications of these results for turbine performance are also discussed. (author)

  6. Experimental and Numerical Study on Performance of Ducted Hydrokinetic Turbines with Pre-Swirl Stator Blades.

    Science.gov (United States)

    Gish, Andrew

    2015-11-01

    Ducts (also called shrouds) have been shown to improve performance of hydrokinetic turbines in some situations, bringing the power coefficient (Cp) closer to the Betz limit. Here we investigate optimization of the duct design as well as the addition of stator blades upstream of the turbine rotor to introduce pre-swirl in the flow. A small scale three-bladed turbine was tested in a towing tank. Three cases (bare turbine, with duct, and with duct and stators) were tested over a range of flow speeds. Important parameters include duct cross-sectional shape, blade-duct gap, stator cross-sectional shape, and stator angle. For each test, Cp was evaluated as a function of tip speed ratio (TSR). Experimental results were compared with numerical simulations. Results indicate that ducts and stators can improve performance at slower flow speeds and lower the stall speed compared to a bare turbine, but may degrade performance at higher speeds. Ongoing efforts to optimize duct and stator configurations will be discussed.

  7. Design and testing of a deformable wind turbine blade control surface

    International Nuclear Information System (INIS)

    Daynes, S; Weaver, P M

    2012-01-01

    Wind tunnel tests were conducted on a 1.3 m chord NACA 63–418 blade section fitted with an adaptive trailing edge flap. The 20% chord flap had an aramid honeycomb core covered with a silicone skin and was actuated using servo motors. The honeycomb core had a high stiffness in the thickness direction but was compliant in chordwise bending. These anisotropic properties offer a potential solution for the conflicting design requirements found in morphing trailing edge structures. Static and dynamic tests were performed up to a Reynolds number of 5.4 × 10 6 . The tests showed that deflecting the flap from − 10° to + 10° changes the blade section lift coefficient by 1.0 in non-stalled conditions. Dynamic tests showed the flap to be capable of operating up to 9° s −1 using a 15 V power supply. A two-dimensional static aeroelastic model of the morphing flap was developed to analyse strains, predict actuator requirements and study fluid–structure interaction effects. The model was used to conduct parametric studies to further improve the flap design. Potential applications include wind turbine blade load alleviation and increased wind energy capture. (paper)

  8. Effect of a culture-based screening algorithm on tuberculosis incidence in immigrants and refugees bound for the United States: a population-based cross-sectional study.

    Science.gov (United States)

    Liu, Yecai; Posey, Drew L; Cetron, Martin S; Painter, John A

    2015-03-17

    Before 2007, immigrants and refugees bound for the United States were screened for tuberculosis (TB) by a smear-based algorithm that could not diagnose smear-negative/culture-positive TB. In 2007, the Centers for Disease Control and Prevention implemented a culture-based algorithm. To evaluate the effect of the culture-based algorithm on preventing the importation of TB to the United States by immigrants and refugees from foreign countries. Population-based, cross-sectional study. Panel physician sites for overseas medical examination. Immigrants and refugees with TB. Comparison of the increase of smear-negative/culture-positive TB cases diagnosed overseas among immigrants and refugees by the culture-based algorithm with the decline of reported cases among foreign-born persons within 1 year after arrival in the United States from 2007 to 2012. Of the 3 212 421 arrivals of immigrants and refugees from 2007 to 2012, a total of 1 650 961 (51.4%) were screened by the smear-based algorithm and 1 561 460 (48.6%) were screened by the culture-based algorithm. Among the 4032 TB cases diagnosed by the culture-based algorithm, 2195 (54.4%) were smear-negative/culture-positive. Before implementation (2002 to 2006), the annual number of reported cases among foreign-born persons within 1 year after arrival was relatively constant (range, 1424 to 1626 cases; mean, 1504 cases) but decreased from 1511 to 940 cases during implementation (2007 to 2012). During the same period, the annual number of smear-negative/culture-positive TB cases diagnosed overseas among immigrants and refugees bound for the United States by the culture-based algorithm increased from 4 to 629. This analysis did not control for the decline in new arrivals of nonimmigrant visitors to the United States and the decrease of incidence of TB in their countries of origin. Implementation of the culture-based algorithm may have substantially reduced the incidence of TB among newly arrived, foreign-born persons in

  9. Investigation of Flow Behavior around Corotating Blades in a Double-Spindle Lawn Mower Deck

    Directory of Open Access Journals (Sweden)

    Chon W.

    2005-01-01

    Full Text Available When the airflow patterns inside a lawn mower deck are understood, the deck can be redesigned to be efficient and have an increased cutting ability. To learn more, a combination of computational and experimental studies was performed to investigate the effects of blade and housing designs on a flow pattern inside a 1.1m wide corotating double-spindle lawn mower deck with side discharge. For the experimental portion of the study, air velocities inside the deck were measured using a laser Doppler velocimetry (LDV system. A high-speed video camera was used to observe the flow pattern. Furthermore, noise levels were measured using a sound level meter. For the computational fluid dynamics (CFD work, several arbitrary radial sections of a two-dimensional blade were selected to study flow computations. A three-dimensional, full deck model was also developed for realistic flow analysis. The computational results were then compared with the experimental results.

  10. Viscous and Aeroelastic Effects on Wind Turbine Blades. The VISCEL Project. Part II: Aeroelastic Stability Investigations

    Science.gov (United States)

    Chaviaropoulos, P. K.; Soerensen, N. N.; Hansen, M. O. L.; Nikolaou, I. G.; Aggelis, K. A.; Johansen, J.; Gaunaa, Mac; Hambraus, T.; Frhr. von Geyr, Heiko; Hirsch, Ch.; Shun, Kang; Voutsinas, S. G.; Tzabiras, G.; Perivolaris, Y.; Dyrmose, S. Z.

    2003-10-01

    The recent introduction of ever larger wind turbines poses new challenges with regard to understanding the mechanisms of unsteady flow-structure interaction. An important aspect of the problem is the aeroelastic stability of the wind turbine blades, especially in the case of combined flap/lead-lag vibrations in the stall regime. Given the limited experimental information available in this field, the use of CFD techniques and state-of-the-art viscous flow solvers provides an invaluable alternative towards the identification of the underlying physics and the development and validation of sound engineering-type aeroelastic models. Navier-Stokes-based aeroelastic stability analysis of individual blade sections subjected to combined pitch/flap or flap/lead-lag motion has been attempted by the present consortium in the framework of the concluded VISCEL JOR3-CT98-0208 Joule III project.

  11. Vortex-induced vibrations on a modern wind turbine blade

    DEFF Research Database (Denmark)

    Heinz, Joachim Christian; Sørensen, Niels N.; Zahle, Frederik

    2016-01-01

    This article investigates the aero-elastic response of the DTU 10-MW RWT blade in deep stall conditions with angles of attack in the vicinity of 90 degrees. The simulations were conducted with the high-fidelity fluid–structure interaction simulation tool HAWC2CFD employing the multi......-body-based structural model of HAWC2 and the incompressible computational fluid dynamics solver EllipSys3D. The study utilizes detached eddy simulation computations and considers the three-dimensional blade geometry including blade twist and taper. A preliminary frequency analysis of the load variations on a stiff....... Aero-elastic computations of the elastic blade confirmed the findings of the frequency analysis. Inflow conditions with inclination angles between Ψ = 20° and Ψ = 55° and relatively low to moderate wind speeds between V = 16 and V = 26 m s-1 were sufficient to trigger severe edgewise blade vibrations...

  12. Analysis of Different Blade Architectures on small VAWT Performance

    Science.gov (United States)

    Battisti, L.; Brighenti, A.; Benini, E.; Raciti Castelli, M.

    2016-09-01

    The present paper aims at describing and comparing different small Vertical Axis Wind Turbine (VAWT) architectures, in terms of performance and loads. These characteristics can be highlighted by resorting to the Blade Element-Momentum (BE-M) model, commonly adopted for rotor pre-design and controller assessment. After validating the model with experimental data, the paper focuses on the analysis of VAWT loads depending on some relevant rotor features: blade number (2 and 3), airfoil camber line (comparing symmetrical and asymmetrical profiles) and blade inclination (straight versus helical blade). The effect of such characteristics on both power and thrusts (in the streamwise direction and in the crosswise one) as a function of both the blades azimuthal position and their Tip Speed Ratio (TSR) are presented and widely discussed.

  13. Wind turbine blade testing system using base excitation

    Science.gov (United States)

    Cotrell, Jason; Thresher, Robert; Lambert, Scott; Hughes, Scott; Johnson, Jay

    2014-03-25

    An apparatus (500) for fatigue testing elongate test articles (404) including wind turbine blades through forced or resonant excitation of the base (406) of the test articles (404). The apparatus (500) includes a testing platform or foundation (402). A blade support (410) is provided for retaining or supporting a base (406) of an elongate test article (404), and the blade support (410) is pivotally mounted on the testing platform (402) with at least two degrees of freedom of motion relative to the testing platform (402). An excitation input assembly (540) is interconnected with the blade support (410) and includes first and second actuators (444, 446, 541) that act to concurrently apply forces or loads to the blade support (410). The actuator forces are cyclically applied in first and second transverse directions. The test article (404) responds to shaking of its base (406) by oscillating in two, transverse directions (505, 507).

  14. A Long-Period Grating Sensor for Wind Turbine Blades

    DEFF Research Database (Denmark)

    Glavind, Lars

    This PhD project concerns the applied research for providing a novel sensor for measurements on wind turbine blades, based on Long-Period Gratings. The idea is based on the utilization of a special asymmetrical optical fibre with Long-Period Gratings for directional sensitive bend sensing...... blade material, where a suitable process and recoating material were investigated. The sensor was implemented and tested on a full scale wind turbine blade placed on a test rig. This first prototype has demonstrated the capability of the sensor for wind turbine blade monitoring, particular...... the possibility to distinguish between the flap- and edge-wise bend directions on the wind turbine blade, providing a selective sensor. The sensor has proven to be very robust and suitable for this application....

  15. Blade Bearing Friction Estimation of Operating Wind Turbines

    DEFF Research Database (Denmark)

    Perisic, Nevena; Pedersen, Bo Juul; Kirkegaard, Poul Henning

    2012-01-01

    Blade root bearing on a wind turbine (WTG) enables pitching of blades for power control and rotor braking and is a WTG critical component. As the size of modern WTGs is constantly increasing, this leads to relatively less rigid bearings, more sensitive to deformations, thus WTG operational...... reliability can be increased by continuous monitoring of blade bearing. High blade bearing friction is undesirable, as it may be associated with excessive heating of the surfaces, damage and/or inefficient operation. Thus, continuous observation of bearing friction level is crucial for blade bearing health...... monitoring systems. A novel algorithm for online monitoring of bearing friction level is developed combining physical knowledge about pitch system dynamics with state estimator, i.e. observer theory and signal processing assuming realistic sensor availability. Results show estimation of bearing friction...

  16. Development of tooling suitable for stall regulated blades

    Energy Technology Data Exchange (ETDEWEB)

    Hancock, M.

    2001-07-01

    The objectives of the project were to make significant improvements in the production of stall regulated blades in the areas of (a) the tip box, its housing, its mechanism and small GRP parts; (b) mould technology; (c) resins and glues and (d) root tooling. Although wood composite had been identified as a competitive technology for blades, compared with GRP blades, production volumes had been lower; reasons are given. The way in which the four areas identified for investigation were tackled are discussed. The study showed that the mould cycle time can be reduced to two days for a stall regulated blade and the blade quality can be improved by using the composite tip box and new resins. The time required for replication of moulds can be reduced by 40%.

  17. Accelerated fatigue testing of LM 19.1 blades

    DEFF Research Database (Denmark)

    Kristensen, Ole Jesper Dahl; Jørgensen, E.

    2003-01-01

    A series of 19.1 metre wind turbine blades manufactured by LM Glasfiber A/S of Lunderskov, Denmark were subjected to a series of flapwise fatigue tests. The object of these fatigue tests is to evaluate the impact of an increased load on the blade in afatigue test and to give information...... if it is possible to increase the load in fatigue test to shorten test time. The tests were carried out as a part of a project financed by the Danish Energy Agency. During the fatigue tests the blades have beensurveyed with thermal imaging equipment to determine how an increase in fatigue load affects the blade...... material. In addition to the thermal imaging surveillance the blades were instrumented with strain gauges. This report presents the temperature duringtest, calibration test results, moment range measurements, strain statistics, thermal imaging registrations and a determination of the size and cause...

  18. Blade vortex interaction noise reduction techniques for a rotorcraft

    Science.gov (United States)

    Charles, Bruce D. (Inventor); Hassan, Ahmed A. (Inventor); Tadghighi, Hormoz (Inventor); JanakiRam, Ram D. (Inventor); Sankar, Lakshmi N. (Inventor)

    1996-01-01

    An active control device for reducing blade-vortex interactions (BVI) noise generated by a rotorcraft, such as a helicopter, comprises a trailing edge flap located near the tip of each of the rotorcraft's rotor blades. The flap may be actuated in any conventional way, and is scheduled to be actuated to a deflected position during rotation of the rotor blade through predetermined regions of the rotor azimuth, and is further scheduled to be actuated to a retracted position through the remaining regions of the rotor azimuth. Through the careful azimuth-dependent deployment and retraction of the flap over the rotor disk, blade tip vortices which are the primary source for BVI noise are (a) made weaker and (b) pushed farther away from the rotor disk (that is, larger blade-vortex separation distances are achieved).

  19. An aerodynamic study on flexed blades for VAWT applications

    International Nuclear Information System (INIS)

    Micallef, Daniel; Farrugia, Russell; Sant, Tonio; Mollicone, Pierluigi

    2014-01-01

    There is renewed interest in aerodynamics research of VAWT rotors. Lift type, Darrieus designs sometimes use flexed blades to have an 'egg-beater shape' with an optimum Troposkien geometry to minimize the structural stress on the blades. While straight bladed VAWTs have been investigated in depth through both measurements and numerical modelling, the aerodynamics of flexed blades has not been researched with the same level of detail. Two major effects may have a substantial impact on blade performance. First, flexing at the equator causes relatively strong trailing vorticity to be released. Secondly, the blade performance at each station along the blade is influenced by self-induced velocities due to bound vorticity. The latter is not present in a straight bladed configuration. The aim of this research is to investigate these effects in relation to an innovative 4kW wind turbine concept being developed in collaboration with industry known as a self-adjusting VAWT (or SATVAWT). The approach used in this study is based on experimental and numerical work. A lifting line free-wake vortex model was developed. Wind tunnel power and hot-wire velocity measurements were performed on a scaled down, 60cm high, three bladed model in a closed wind tunnel. Results show a substantial axial wake induction at the equator resulting in a lower power generation at this position. This induction increases with increasing degree of flexure. The self-induced velocities caused by blade bound vorticity at a particular station was found to be relatively small

  20. Manufacturing a 9-Meter Thermoplastic Composite Wind Turbine Blade: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Murray, Robynne [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Snowberg, David R [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Berry, Derek S [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Beach, Ryan [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Rooney, Samantha A [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Swan, Dana [Arkema Inc.

    2017-12-06

    Currently, wind turbine blades are manufactured from a combination of glass and/or carbon fiber composite materials with a thermoset resin such as epoxy, which requires energy-intensive and expensive heating processes to cure. Newly developed in-situ polymerizing thermoplastic resin systems for composite wind turbine blades polymerize at room temperature, eliminating the heating process and significantly reducing the blade manufacturing cycle time and embodied energy, which in turn reduces costs. Thermoplastic materials can also be thermally welded, eliminating the need for adhesive bonds between blade components and increasing the overall strength and reliability of the blades. As well, thermoplastic materials enable end-of-life blade recycling by reheating and decomposing the materials, which is a limitation of existing blade technology. This paper presents a manufacturing demonstration for a 9-m-long thermoplastic composite wind turbine blade. This blade was constructed in the Composites Manufacturing Education and Technology facility at the National Wind Technology Center at the National Renewable Energy Laboratory (NREL) using a vacuum-assisted resin transfer molding process. Johns Manville fiberglass and an Arkema thermoplastic resin called Elium were used. Additional materials included Armacell-recycled polyethylene terephthalate foam from Creative Foam and low-cost carbon- fiber pultruded spar caps (manufactured in collaboration with NREL, Oak Ridge National Laboratory, Huntsman, Strongwell, and Chomarat). This paper highlights the development of the thermoplastic resin formulations, including an additive designed to control the peak exothermic temperatures. Infusion and cure times of less than 3 hours are also demonstrated, highlighting the efficiency and energy savings associated with manufacturing thermoplastic composite blades.

  1. Definition of a 5MW/61.5m wind turbine blade reference model.

    Energy Technology Data Exchange (ETDEWEB)

    Resor, Brian Ray

    2013-04-01

    A basic structural concept of the blade design that is associated with the frequently utilized %E2%80%9CNREL offshore 5-MW baseline wind turbine%E2%80%9D is needed for studies involving blade structural design and blade structural design tools. The blade structural design documented in this report represents a concept that meets basic design criteria set forth by IEC standards for the onshore turbine. The design documented in this report is not a fully vetted blade design which is ready for manufacture. The intent of the structural concept described by this report is to provide a good starting point for more detailed and targeted investigations such as blade design optimization, blade design tool verification, blade materials and structures investigations, and blade design standards evaluation. This report documents the information used to create the current model as well as the analyses used to verify that the blade structural performance meets reasonable blade design criteria.

  2. Identification and management of cracking in 410 stainless turbine blade roots

    International Nuclear Information System (INIS)

    Clark, M.A.; Lehockey, E.M.; Thompson, I.; Massey, R.

    2003-01-01

    estimated that cracks had been propagating for between 6 and 10 years (of the total 20-year operating life). This is approximately consistent with general guidelines wherein cracks can be expected to initiate during the last 30% of fatigue life. On this basis, and in the absence of other compelling metallurgical evidence suggesting an alternate root-cause, these blades were believed to have reached end of fatigue life. Similitude in the beachmark patterns among the affected blades suggested stable and consistent growth characteristics. In addition, blades appeared to remain intact despite sustaining cracks that propagated through a large fraction of the root cross-section. The stable propagation characteristics combined with the apparently large 'safety' margins provided the opportunity for conducting regular inspections (phased array and MPI) to ensure reliable operation between turbine outages until replacement options could be developed and implemented. Subsequent inspections of row 10 blades in other identical turbines have not detected any other cracked blades to date. In contrast, two of the blades examined exhibited clear evidence of intergranular cracking along prior austenite grain boundaries consistent with stress corrosion cracking (Figure 3). Hardness on both of these blades approached or exceeded 400 HVN. Susceptibility to stress corrosion cracking increases significantly with hardness. Fracture surfaces contained elevated levels of Mo, 5, Cl, and F. Molybenum and sulfur were traced in part to the (Moly Paul) grease lubricant applied to mate the blade root to the turbine steeple during installation. Other contaminants established from Ion Chromatography included unusually high levels of carbon in the form of organics including formates, acetates, and glycolates as well as nitrates, sulfates, and oxalates. Origins of this contamination include throw from cation resins in the water treatment plant, thermal degradation and oxidation by air ingress of the volatile

  3. Mechanisms and actuators for rotorcraft blade morphing

    Science.gov (United States)

    Vocke, Robert D., III

    The idea of improved fight performance through changes in the control surfaces dates back to the advent of aviation with the Wright brothers' pioneering work on "wing warping," but it was not until the recent progress in material and actuator development that such control surfaces seemed practical for modern aircraft. This has opened the door to a new class of aircraft that have the ability to change shape or morph, which are being investigated due to the potential to have a single platform serve multiple mission objectives, as well as improve performance characteristics. While the majority of existing research for morphing aircraft has focused on fixedwing aircraft, rotary-wing aircraft have begun to receive more attention. The purpose of this body of work is to investigate the current state of morphing actuation technology for rotorcraft and improve upon it. Specifically, this work looks at two types of morphing: Pneumatic Artificial Muscle (PAM) actuated trailing edge flaps and conformal variable diameter morphing. First, active camber changes through the use of PAM powered trailing edge flaps were investigated due to the potential for reductions in power requirements and vibration/noise levels. A PAM based antagonistic actuation system was developed utilizing a novel combination of mechanism geometry and PAM bias contraction optimization to overcome the natural extension stiffening characteristics of PAMs. In open-loop bench-top testing against a "worst-case" constant torsional loading, the system demonstrated actuation authority suitable for both primary control and vibration/noise reduction. Additionally, closed-loop test data indicated that the system was capable of tracking complex waveforms consistent with those needed for rotorcraft control. This system demonstrated performance on-par with the state of the art pneumatic trailing edge flap actuators, yet with a much smaller footprint and impact on the rotor-blade. The second morphing system developed in

  4. Impact force identification for composite helicopter blades using minimal sensing

    Science.gov (United States)

    Budde, Carson N.

    In this research a method for online impact identification using minimal sensors is developed for rotor hubs with composite blades. Modal impact data and the corresponding responses are recorded at several locations to develop a frequency response function model for each composite blade on the rotor hub. The frequency response model for each blade is used to develop an impact identification algorithm which can be used to identify the location and magnitude of impacts. Impacts are applied in two experimental setups, including a four-blade spin test rig and a cantilevered full-sized composite blade. The impacts are estimated to have been applied at the correct location 92.3% of the time for static fiberglass blades, 97.4% of the time for static carbon fiber blades and 99.2% of the time for a full sized-static blade. The estimated location is assessed further and determined to have been estimated in the correct chord position 96.1% of the time for static fiberglass, 100% of the time for carbon fiber blades and 99.2% of the time for the full-sized blades. Projectile impacts are also applied statically and during rotation to the carbon fiber blades on the spin test rig at 57 and 83 RPM. The applied impacts can be located to the correct position 63.9%, 41.7% and 33.3% for the 0, 57 and 83 RPM speeds, respectively, while the correct chord location is estimated 100% of the time. The impact identification algorithm also estimates the force of an impact with an average percent difference of 4.64, 2.61 and 1.00 for static fiberglass, full sized, and carbon fiber blades, respectively. Using a load cell and work equations, the force of impact for a projectile fired from a dynamic firing setup is estimated at about 400 N. The average force measured for applied projectile impacts to the carbon fiber blades, rotating at 0, 57 and 83 RPM, is 368.8, 373.7 and 432.4 N, respectively.

  5. Effect of number of blades on aerodynamic forces on a straight-bladed Vertical Axis Wind Turbine

    International Nuclear Information System (INIS)

    Li, Qing'an; Maeda, Takao; Kamada, Yasunari; Murata, Junsuke; Furukawa, Kazuma; Yamamoto, Masayuki

    2015-01-01

    Small wind turbine performance and safety standard for straight-bladed Vertical Axis Wind Turbine (VAWT) have not been developed in the world because of the lack of fundament experimental data. This paper focuses on the evaluation of aerodynamic forces depending on several numbers of blades in wind tunnel experiment. In the present study, the test airfoil of blade is symmetry airfoil of NACA 0021 and the number of blades is from two to five. Pressure acting on the surface of rotor blade is measured during rotation by multiport pressure devices and transmitted to a stationary system through wireless LAN. And then, the aerodynamic forces (tangential force, normal force et al.) are discussed as a function of azimuth angle, achieving a quantitative analysis of the effect of numbers of blades. Finally, the loads are compared with the experimental data of six-component balance. As a result, it is clarified that the power coefficient decreases with the increase of numbers of blades. Furthermore, the power which is absorbed from wind by wind turbine mainly depends on upstream region of azimuth angle of θ = 0°∼180°. In this way, these results are very important for developing the simple design equations and applications for straight-bladed VAWT. - Highlights: • Aerodynamic forces are measured by not only torque meter but also six-component balance. • The pressure distribution on the surface of rotor blade is directly measured by multiport pressure devices. • The power coefficient decreases with the increase of numbers of blades. • The fluctuation amplitudes from six-component balance show larger value than the results of pressure distribution.

  6. Comparison of CFD simulations to non-rotating MEXICO blades experiment in the LTT wind tunnel of TUDelft

    International Nuclear Information System (INIS)

    Zhang, Ye; Van Zuijlen, Alexander; Van Bussel, Gerard

    2014-01-01

    In this paper, three dimensional flow over non-rotating MEXICO blades is simulated by CFD methods. The numerical results are compared with the latest MEXICO wind turbine blades measurements obtained in the low speed low turbulence (LTT) wind tunnel of Delft University of Technology. This study aims to validate CFD codes by using these experimental data measured in well controlled conditions. In order to avoid use of wind tunnel corrections, both the blades and the wind tunnel test section are modelled in the simulations. The ability of Menter's k – ω shear stress transport (SST) turbulence model is investigated at both attached flow and massively separated flow cases. Steady state Reynolds averaged Navier Stokes (RANS) equations are solved in these computations. The pressure distribution at three measured sections are compared under the conditions of different inflow velocities and a range of angles of attack. The comparison shows that at attached flow condition, good agreement can be obtained for all three airfoil sections. Even with massively separated flow, still fairly good pressure distribution comparison can be found for the DU and NACA airfoil sections, although the RISØ section shows poor comparison. At the near stall case, considerable deviations exists on the forward half part of the upper surface for all three sections

  7. Estimation of Efficiency of the Cooling Channel of the Nozzle Blade of Gas-Turbine Engines

    Science.gov (United States)

    Vikulin, A. V.; Yaroslavtsev, N. L.; Zemlyanaya, V. A.

    2018-02-01

    The main direction of improvement of gas-turbine plants (GTP) and gas-turbine engines (GTE) is increasing the gas temperature at the turbine inlet. For the solution of this problem, promising systems of intensification of heat exchange in cooled turbine blades are developed. With this purpose, studies of the efficiency of the cooling channel of the nozzle blade in the basic modification and of the channel after constructive measures for improvement of the cooling system by the method of calorimetry in a liquid-metal thermostat were conducted. The combined system of heat-exchange intensification with the complicated scheme of branched channels is developed; it consists of a vortex matrix and three rows of inclined intermittent trip strips. The maximum value of hydraulic resistance ξ is observed at the first row of the trip strips, which is connected with the effect of dynamic impact of airflow on the channel walls, its turbulence, and rotation by 117° at the inlet to the channels formed by the trip strips. These factors explain the high value of hydraulic resistance equal to 3.7-3.4 for the first row of the trip strips. The obtained effect was also confirmed by the results of thermal tests, i.e., the unevenness of heat transfer on the back and on the trough of the blade is observed at the first row of the trip strips, which amounts 8-12%. This unevenness has a fading character; at the second row of the trip strips, it amounts to 3-7%, and it is almost absent at the third row. At the area of vortex matrix, the intensity of heat exchange on the blade back is higher as compared to the trough, which is explained by the different height of the matrix ribs on its opposite sides. The design changes in the nozzle blade of basic modification made it possible to increase the intensity of heat exchange by 20-50% in the area of the vortex matrix and by 15-30% on the section of inclined intermittent trip strips. As a result of research, new criteria dependences for the

  8. 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.

  9. Rotational effects on turbine blade cooling

    Energy Technology Data Exchange (ETDEWEB)

    Govatzidakis, G.J.; Guenette, G.R.; Kerrebrock, J.L. [Massachusetts Institute of Technology, Cambridge, MA (United States)

    1995-10-01

    An experimental investigation of the influence of rotation on the heat transfer in a smooth, rectangular passage rotating in the orthogonal mode is presented. The passage simulates one of the cooling channels found in gas turbine blades. A constant heat flux is imposed on the model with either inward or outward flow. The effects of rotation and buoyancy on the Nusselt number were quantified by systematically varying the Rotation number, Density Ratio, Reynolds number, and Buoyancy parameter. The experiment utilizes a high resolution infrared temperature measurement technique in order to measure the wall temperature distribution. The experimental results show that the rotational effects on the Nusselt number are significant and proper turbine blade design must take into account the effects of rotation, buoyancy, and flow direction. The behavior of the Nusselt number distribution depends strongly on the particular side, axial position, flow direction, and the specific range of the scaling parameters. The results show a strong coupling between buoyancy and Corollas effects throughout the passage. For outward flow, the trailing side Nusselt numbers increase with Rotation number relative to stationary values. On the leading side, the Nusselt numbers tended to decrease with rotation near the inlet and subsequently increased farther downstream in the passage. The Nusselt numbers on the side walls generally increased with rotation. For inward flow, the Nusselt numbers generally improved relative to stationary results, but increases in the Nusselt number were relatively smaller than in the case of outward flow. For outward and inward flows, increasing the density ratio generally tended to decrease Nusselt numbers on the leading and trailing sides, but the exact behavior and magnitude depended on the local axial position and specific range of Buoyancy parameters.

  10. Characterization of a Viking Blade Fabricated by Traditional Forging Techniques

    Science.gov (United States)

    Vo, H.; Frazer, D.; Bailey, N.; Traylor, R.; Austin, J.; Pringle, J.; Bickel, J.; Connick, R.; Connick, W.; Hosemann, P.

    2016-12-01

    A team of students from the University of California, Berkeley, participated in a blade-smithing competition hosted by the Minerals, Metals, and Materials Society at the TMS 2015 144th annual meeting and exhibition. Motivated by ancient forging methods, the UC Berkeley team chose to fabricate our blade from historical smithing techniques utilizing naturally-occurring deposits of iron ore. This approach resulted in receiving the "Best Example of a Traditional Blade Process/Ore Smelting Technique" award for our blade named "Berkelium." First, iron-enriched sand was collected from local beaches. Magnetite (Fe3O4) was then extracted from the sand and smelted into individual high- and low-carbon steel ingots. Layers of high- and low-carbon steels were forge-welded together, predominantly by hand, to form a composite material. Optical microscopy, energy dispersive spectroscopy, and Vickers hardness mechanical testing were conducted at different stages throughout the blade-making process to evaluate the microstructure and hardness evolution during formation. It was found that the pre-heat-treated blade microstructure was composed of ferrite and pearlite, and contained many nonmetallic inclusions. A final heat treatment was performed, which caused the average hardness of the blade edge to increase by more than a factor of two, indicating a martensitic transformation.

  11. Verification of Thermal Models of Internally Cooled Gas Turbine Blades

    Directory of Open Access Journals (Sweden)

    Igor Shevchenko

    2018-01-01

    Full Text Available Numerical simulation of temperature field of cooled turbine blades is a required element of gas turbine engine design process. The verification is usually performed on the basis of results of test of full-size blade prototype on a gas-dynamic test bench. A method of calorimetric measurement in a molten metal thermostat for verification of a thermal model of cooled blade is proposed in this paper. The method allows obtaining local values of heat flux in each point of blade surface within a single experiment. The error of determination of local heat transfer coefficients using this method does not exceed 8% for blades with radial channels. An important feature of the method is that the heat load remains unchanged during the experiment and the blade outer surface temperature equals zinc melting point. The verification of thermal-hydraulic model of high-pressure turbine blade with cooling allowing asymmetrical heat removal from pressure and suction sides was carried out using the developed method. An analysis of heat transfer coefficients confirmed the high level of heat transfer in the leading edge, whose value is comparable with jet impingement heat transfer. The maximum of the heat transfer coefficients is shifted from the critical point of the leading edge to the pressure side.

  12. Enhancing wind turbines efficiency with passive reconfiguration of flexible blades

    Science.gov (United States)

    Cognet, Vincent P. A.; Thiria, Benjamin; Courrech Du Pont, Sylvain; MSC Team; PMMH Team

    2015-11-01

    Nature provides excellent examples where flexible materials are advantageous in a fluid stream. By folding, leaves decrease the drag caused by air stream; and birds' flapping is much more efficient with flexible wings. Motivated by this, we investigate the effect of flexible blades on the performance of a wind turbine. The effect of chordwise flexible blades is studied both experimentally and theoretically on a small wind turbine in steady state. Four parameters are varied: the wind velocity, the resisting torque, the pitch angle, and the blade's bending modulus. We find an optimum efficiency with respect to the bending modulus. By tuning our four parameters, the wind turbine with flexible blades has a high-efficiency range significantly larger than rigid blades', and, furthermore enhances the operating range. These results are all the more important as one of the current issues concerning wind turbines is the enlargement of their operating range. To explain these results, we propose a simple two-dimensional model by discretising the blade along the radius. We take into account the variation of drag and lift coefficients with the bending ability. This model matches experimental observations and demonstrates the contribution of the reconfiguration of the blade. Matiere et Systemes Complexes.

  13. Life assessment of gas turbine blades after long term service

    Energy Technology Data Exchange (ETDEWEB)

    Auerkari, Pertti; Salonen, Jorma [VTT, Espoo (Finland); Maekinen, Sari [Helsingin Energia, Helsinki (Finland); Karvonen, Ikka; Tanttari, Heikki [Lappeenrannan Laempoevoima, Lappeenranta (Finland); Kangas, Pekka [Neste Oil, Kilpilahti (Finland); Scholz, Alfred [Technische Univ. Darmstadt (Germany); Vacchieri, Erica [Ansaldo Richerche, Genoa (Italy)

    2010-07-01

    Turbine blade samples from three land based gas turbines have been subjected to systematic condition and life assessment after long term service (88000 - 109000 equivalent operating hours, eoh), when approaching the nominal or suggested life limits. The blades represent different machine types, materials and design generations, and uncooled blading outside the hottest front end of the turbine, i.e. blades with relatively large size and considerable expected life. For a reasonable assessment, a range of damage mechanisms need to be addressed and evaluated for the impact in the residual life. The results suggested significant additional safe life for all three blade sets. In some cases this could warrant yet another life cycle comparable to that of new blades, even after approaching the nominal end of life in terms of recommended equivalent operating hours. This is thought to be partly because of base load combined cycle operation and natural gas fuel, or modest operational loading if the design also accounted for more intensive cycling operation and more corrosive oil firing. In any case, long term life extension is only appropriate if not intervened by events of overloading, overheating or other sudden events such as foreign object damage (FOD), and if supported by the regular inspection and maintenance program to control in-service damage. Condition based assessment therefore remains an important part of the blade life management after the decision of accepted life extension. (orig.)

  14. Shikarpur lithic assemblage: New questions regarding Rohri chert blade production

    Directory of Open Access Journals (Sweden)

    Charusmita Gadekar

    2014-03-01

    Full Text Available Recent excavations at Shikarpur, a fortified Harappan site situated near the Gulf of Kuchchh in Gujarat, Western India, brought to light a large collection of Rohri chert blades.  Chert found in the Rohri hill near Sukkur in Sindh, central Pakistan is distinctive and easily identifiable. The wide distribution of standardized Rohri chert blades is often regarded as a testimony to the Harappan efficiency in long distance trade and craft production.  The possibility of localized production of Rohri chert blades in Gujarat is often negated due to the constraints of raw-material availability.  The absence of Rohri chert working debitage from most of the sites in Gujarat, has lent support to this position. The Shikarpur Rohri blade assemblage however incorporates more than 650 blades, a large fluted blade-core and a few Rohri chert debitage.  These have led the excavators to suggest that some of the blades found at Shikarpur were locally produced from raw materials brought to the site from the Rohri hills.  Typo-technological features of the Rohri chert assemblage from Shikarpur have been analysed in this background. These along with metrical features of the assemblage are compared with Rohri chert assemblages from other major Harappan sites in the region to check the validity of the proposed ‘limited local production’.

  15. Study of Pumping Capacity of Pitched Blade Impellers

    Directory of Open Access Journals (Sweden)

    I. Fořt

    2002-01-01

    Full Text Available A study was made of the pumping capacity of pitched blade impellers in a cylindrical pilot plant vessel with four standard radial baffles at the wall under a turbulent regime of flow. The pumping capacity was calculated from the radial profile of the axial flow, under the assumption of axial symmetry of the discharge flow. The mean velocity was measured using laser Doppler anemometry in a transparent vessel of diameter T = 400 mm, provided with a standard dished bottom. Three and six blade pitched blade impellers (the pitch angle varied within the interval a Îá24°; 45°ń of impeller/vessel diameter ratio D/T = 0.36, as well as a three blade pitched blade impeller with folded blades of the same diameter, were tested. The calculated results were compared with the results of experiments mentioned in the literature, above all in cylindrical vessels with a flat bottom. Both arrangements of the agitated system were described by the impeller energetic efficiency, i.e, a criterion including in dimensionless form both the impeller energy consumption (impeller power input and the impeller pumping effect (impeller pumping capacity. It follows from the results obtained with various geometrical configurations that the energetic efficiency of pitched blade impellers is significantly lower for configurations suitable for mixing solid-liquid suspensions (low impeller off bottom clearances than for blending miscible liquids in mixing (higher impeller off bottom clearances.

  16. Optimization design of spar cap layup for wind turbine blade

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    Based on the aerodynamic shape and structural form of the blade are fixed,a mathematical model of optimization design for wind turbine blade is established.The model is pursued with respect to minimum the blade mass to reduce the cost of wind turbine production.The material layup numbers of the spar cap are chosen as the design variables;while the demands of strength,stiffness and stability of the blade are employed as the constraint conditions.The optimization design for a 1.5 MW wind turbine blade is carried out by combing above objective and constraint conditions at the action of ultimate flapwise loads with the finite element software ANSYS.Compared with the original design,the optimization design result achieves a reduction of 7.2% of the blade mass,the stress and strain distribution of the blade is more reasonable,and there is no occurrence of resonance,therefore its effectiveness is verified.

  17. Helicopter blades running elevation measurement using omnidirectional vision

    Directory of Open Access Journals (Sweden)

    Chengtao CAI

    2017-12-01

    Full Text Available Omnidirectional dynamic space parameters of high-speed rotating helicopter blades are precise 3D vector description of the blades. In particular, the elevation difference is directly related to the aerodynamic performance and maneuverability of the helicopter. The state of the art detection techniques based on optics and common vision have several drawbacks, such as high demands on devices but poor extensibility, limited measurement range and fixed measurement position. In this paper, a novel approach of helicopter blades running elevation measurement is proposed based on omnidirectional vision. With the advantages of panoramic visual imaging integration, 360° field of view and rotation in-variance, high-resolution images of all rotating blades positions are obtained at one time. By studying the non-linear calibration and calculation model of omnidirectional vision system, aiming at solving the problem of inaccurate visual space mapping model, the omnidirectional and full-scale measurement of the elevation difference are finalized. Experiments are carried out on our multifunctional simulation blades test system and the practical blades test tower, respectively. The experimental results demonstrate the effectiveness of the proposed method and show that the proposed method can considerably reduce the complexity of measurement. Keywords: Full-scale measurement, Helicopter blades elevation, Non-linear calibration, Omnidirectional vision, Unified sphere model

  18. AERFORCE: Subroutine package for unsteady blade-element/momentum calculations

    Energy Technology Data Exchange (ETDEWEB)

    Bjoerck, Anders

    2000-05-01

    A subroutine package, called AERFORCE, for the calculation of aerodynamic forces of wind turbine rotors has been written. The subroutines are written in FORTRAN. AERFORCE requires the input of airfoil aerodynamic data via tables as function of angle of attack, the turbine blade and rotor geometry and wind and blade velocities as input. The method is intended for use in an aeroelastic code. Wind and blade velocities are given at a sequence of time steps and blade forces are returned. The aerodynamic method is basically a Blade-Element/Momentum method. The method is fast and coded to be used in time simulations. In order to obtain a steady state solution a time simulation to steady state conditions has to be carried out. The BEM-method in AERFORCE includes extensions for: Dynamic inflow: Unsteady modeling of the inflow for cases with unsteady blade loading or unsteady wind. Extensions to BEM-theory for inclined flow to the rotor disc (yaw model). Unsteady blade aerodynamics: The inclusion of 2D attached flow unsteady aerodynamics and a semi-empirical model for 2D dynamic stall.

  19. Effects of large bending deflections on blade flutter limits

    Energy Technology Data Exchange (ETDEWEB)

    Kallesoee, Bjarne Skovmose; Hartvig Hansen, Morten

    2008-04-15

    The coupling of bending and torsion due to large blade bending are assumed to have some effects of the flutter limits of wind turbines. In the present report, the aeroelastic blade model suggested by Kallesoee, which is similar to a second order model, is used to investigate the aeroelastic stability limits of the RWT blade with and without the effects of the large blade deflection. The investigation shows no significant change of the flutter limit on the rotor speed due to the blade deflection,whereas the first edgewise bending mode becomes negatively damped due to the coupling with blade torsion which causes a change of the effective direction of blade vibration. These observations are confirmed by nonlinear aeroelastic simulations using HAWC2. This work is part of the UpWind project funded by the European Commission under the contract number SES6-CT-2005-019945 which is gratefully acknowledged. This report is the deliverable D2.3 of the UpWind project. (au)

  20. Structural damage and chemical contaminants on reprocessed arthroscopic shaver blades.

    Science.gov (United States)

    Kobayashi, Masahiko; Nakagawa, Yasuaki; Okamoto, Yukihiro; Nakamura, Shinichiro; Nakamura, Takashi

    2009-02-01

    In response to socioeconomic pressure to cut budgets in medicine, single-use surgical instruments are often reprocessed despite potential biological hazard. To evaluate the quality and contaminants of reprocessed shaver blades. Reprocessed shaver blades have mechanical damage and chemical contamination. Controlled laboratory study. Seven blades and 3 abraders were reprocessed 1 time or 3 times and then were assessed. In the first part of the study, structural damage on the blades after 3 reprocessings was compared to that after 1 reprocessing using optical microscopy. In the second part, surface damage was observed using optical microscopy and scanning electron microscopy; elemental and chemical analyses of contaminants found by the microscopy were performed using scanning electron microscopy/energy dispersive x-ray spectroscopy, scanning Auger microscopy, and Fourier transform infrared spectroscopy. Optical microscopic examination revealed abrasion on the surface of the inner blade and cracks on the inner tube after 1 reprocessing. These changes were more evident after 3 reprocessings. Scanning electron microscopy/energy dispersive x-ray spectroscopy of the inner cutter of the blade reprocessed once showed contaminants containing calcium, carbon, oxygen, and silicon, and Fourier transform infrared spectroscopy demonstrated biological protein consisting mainly of collagen, some type of salts, and polycarbonate used in plastic molding. Scanning electron microscopy/energy dispersive x-ray spectroscopy of the inner cutter of the reprocessed abrader revealed contaminants containing carbon, calcium, phosphorous, and oxygen, and Fourier transform infrared spectroscopy showed H2O, hydroxyapatite, and hydroxyl proteins. Scanning Auger microscopy showed that the tin-nickel plating on the moving blade and abrader was missing in some locations. This is the first study to evaluate both mechanical damage and chemical contaminants containing collagen, hydroxyapatite, and salts

  1. Results of the benchmark for blade structural models, part A

    DEFF Research Database (Denmark)

    Lekou, D.J.; Chortis, D.; Belen Fariñas, A.

    2013-01-01

    A benchmark on structural design methods for blades was performed within the InnWind.Eu project under WP2 “Lightweight Rotor” Task 2.2 “Lightweight structural design”. The present document is describes the results of the comparison simulation runs that were performed by the partners involved within...... Task 2.2 of the InnWind.Eu project. The benchmark is based on the reference wind turbine and the reference blade provided by DTU [1]. "Structural Concept developers/modelers" of WP2 were provided with the necessary input for a comparison numerical simulation run, upon definition of the reference blade...

  2. Quantifying uncertainties in the structural response of SSME blades

    Science.gov (United States)

    Nagpal, Vinod K.

    1987-01-01

    To quantify the uncertainties associated with the geometry and material properties of a Space Shuttle Main Engine (SSME) turbopump blade, a computer code known as STAEBL was used. A finite element model of the blade used 80 triangular shell elements with 55 nodes and five degrees of freedom per node. The whole study was simulated on the computer and no real experiments were conducted. The structural response has been evaluated in terms of three variables which are natural frequencies, root (maximum) stress, and blade tip displacements. The results of the study indicate that only the geometric uncertainties have significant effects on the response. Uncertainties in material properties have insignificant effects.

  3. Tracked Robot with Blade Arms to Enhance Crawling Capability

    OpenAIRE

    Jhu-Wei Ji; Fa-Shian Chang; Lih-Tyng Hwang; Chih-Feng Liu; Jeng-Nan Lee; Shun-Min Wang; Kai-Yi Cho

    2016-01-01

    This paper presents a tracked robot with blade arms powered to assist movement in difficult environments. As a result, the tracked robot is able to pass a ramp or climb stairs. The main feature is a pair of blade arms on both sides of the vehicle body working in collaboration with previously validated transformable track system. When the robot encounters an obstacle in a terrain, it enlists the blade arms with power to overcome the obstacle. In disaster areas, there usually will be terrains t...

  4. Structural design optimization of a morphing trailing edge flap for wind turbine blades

    DEFF Research Database (Denmark)

    Barlas, Athanasios; Lin, Yu-Huan; Aagaard Madsen, Helge

    A flap actuation system, the Controllable Rubber Trailing Edge Flap (CRTEF), for distributed load control on a wind turbine blade had been developed in the period from 2006 to 2013 at DTU (http://www.induflap.dk/). The purpose of the presented work is to optimize the structural design of the flex......A flap actuation system, the Controllable Rubber Trailing Edge Flap (CRTEF), for distributed load control on a wind turbine blade had been developed in the period from 2006 to 2013 at DTU (http://www.induflap.dk/). The purpose of the presented work is to optimize the structural design...... of the flexible part of the CRTEF based on a realistic blade section geometry in order to meet the required objectives and constraints. The objectives include the deflection requirements and the energy efficiency, while the constraints include the bending stiffness of the structure, the local shape deformations......, critical material strength, and manufacturing limitations. A model with arches forming concave on the flap surface and enclosing the voids to be pressurized results in the bending movement of the flap when pressure is applied on the voids to straighten the arches. The model is designed using SolidWorks...

  5. Influence of Shock Wave on the Flutter Behavior of Fan Blades Investigated

    Science.gov (United States)

    Srivastava, Rakesh; Bakhle, Milind A.; Stefko, George L.

    2003-01-01

    Modern fan designs have blades with forward sweep; a lean, thin cross section; and a wide chord to improve performance and reduce noise. These geometric features coupled with the presence of a shock wave can lead to flutter instability. Flutter is a self-excited dynamic instability arising because of fluid-structure interaction, which causes the energy from the surrounding fluid to be extracted by the vibrating structure. An in-flight occurrence of flutter could be catastrophic and is a significant design issue for rotor blades in gas turbines. Understanding the flutter behavior and the influence of flow features on flutter will lead to a better and safer design. An aeroelastic analysis code, TURBO, has been developed and validated for flutter calculations at the NASA Glenn Research Center. The code has been used to understand the occurrence of flutter in a forward-swept fan design. The forward-swept fan, which consists of 22 inserted blades, encountered flutter during wind tunnel tests at part speed conditions.

  6. Insight into Rotational Effects on a Wind Turbine Blade Using Navier–Stokes Computations

    Directory of Open Access Journals (Sweden)

    Iván Herráez

    2014-10-01

    Full Text Available Rotational effects are known to influence severely the aerodynamic performance of the inboard region of rotor blades. The underlying physical mechanisms are however far from being well understood. The present work addresses this problem using Reynolds averaged Navier–Stokes computations and experimental results of the MEXICO (Model Experiments in Controlled Conditions rotor. Four axisymmetric inflow cases with wind speeds ranging from pre-stall to post-stall conditions are computed and compared with pressure and particle image velocimetry (PIV experimental data, obtaining, in general, consistent results. At low angles of attack, the aerodynamic behavior of all of the studied blade sections resembles the one from the corresponding 2D airfoils. However, at high angles of attack, rotational effects lead to stall delay and/or lift enhancement at inboard positions. Such effects are shown to occur only in the presence of significant radial flows. Interestingly, the way in which rotational effects influence the aerodynamics of the MEXICO blades differs qualitatively in certain aspects from the descriptions found in the literature about this topic. The presented results provide new insights that are useful for the development of advanced and physically-sound correction models.

  7. Innovative approach to computer-aided design of horizontal axis wind turbine blades

    Directory of Open Access Journals (Sweden)

    Seyed Farhad Hosseini

    2017-04-01

    Full Text Available The design of horizontal axis wind turbine (HAWT blades involves several geometric complexities. As a result, the modeling of these blades by commercial computer-aided design (CAD software is not easily accomplished. In the present paper, the HAWT blade is divided into structural and aerodynamic surfaces with a G1 continuity imposed on their connecting region. The widely used method of skinning is employed throughout the current work for surface approximation. In addition, to ensure the compatibility of section curves, a novel approach is developed based on the redistribution of input airfoil points. In order to evaluate deviation errors, the Hausdorff metric is used. The fairness of surfaces is quantitatively assessed using the standard strain energy method. The above-mentioned algorithms are successfully integrated into a MATLAB program so as to enhance further optimization applications. The final surfaces created by the procedure developed during the present study can be exported using the IGES standard file format and directly interpreted by commercial CAD and FE software.

  8. Detailed analysis of the blade root flow of a horizontal axis wind turbine

    Directory of Open Access Journals (Sweden)

    I. Herráez

    2016-07-01

    Full Text Available The root flow of wind turbine blades is subjected to complex physical mechanisms that influence significantly the rotor aerodynamic performance. Spanwise flows, the Himmelskamp effect, and the formation of the root vortex are examples of interrelated aerodynamic phenomena that take place in the blade root region. In this study we address those phenomena by means of particle image velocimetry (PIV measurements and Reynolds-averaged Navier–Stokes (RANS simulations. The numerical results obtained in this study are in very good agreement with the experiments and unveil the details of the intricate root flow. The Himmelskamp effect is shown to delay the stall onset and to enhance the lift force coefficient Cl even at moderate angles of attack. This improvement in the aerodynamic performance occurs in spite of the negative influence of the mentioned effect on the suction peak of the involved blade sections. The results also show that the vortex emanating from the spanwise position of maximum chord length rotates in the opposite direction to the root vortex, which affects the wake evolution. Furthermore, the aerodynamic losses in the root region are demonstrated to take place much more gradually than at the tip.

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

    DEFF Research Database (Denmark)

    Wang, Xudong; Chen, Jin; Zhang, Shigiang

    2010-01-01

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

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

    DEFF Research Database (Denmark)

    Kallesøe, Bjarne Skovmose

    2011-01-01

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

  11. Study on Determination Method of Fatigue Testing Load for Wind Turbine Blade

    Science.gov (United States)

    Liao, Gaohua; Wu, Jianzhong

    2017-07-01

    In this paper, the load calculation method of the fatigue test was studied for the wind turbine blade under uniaxial loading. The characteristics of wind load and blade equivalent load were analyzed. The fatigue property and damage theory of blade material were studied. The fatigue load for 2MW blade was calculated by Bladed, and the stress calculated by ANSYS. Goodman modified exponential function S-N curve and linear cumulative damage rule were used to calculate the fatigue load of wind turbine blades. It lays the foundation for the design and experiment of wind turbine blade fatigue loading system.

  12. Steady State Structural Analysis of High Pressure Gas Turbine Blade using Finite Element Analysis

    Science.gov (United States)

    Mazarbhuiya, Hussain Mahamed Sahed Mostafa; Murari Pandey, Krishna

    2017-08-01

    In gas turbines the major portion of performance dependency lies upon turbine blade design. Turbine blades experience very high centrifugal, axial and tangential force during power generation. While withstanding these forces blades undergo elongation. Different methods have proposed for better enhancement of the mechanical properties of blade to withstand in extreme condition. Present paper describes the stress and elongation for blades having properties of different materials. Steady state structural analysis have performed in the present work for different materials (In 625, In 718, In 738, In 738 LC, MAR M246, Ni-Cr, Ti-alloy, Ti-Al, Ti-T6, U500). Remarkable finding is that the root of the blade is subjected to maximum stress for all blade materials and the blade made of MAR M246 has less stress and deformation among all other blade materials which can be selected as a suitable material for gas turbine blade.

  13. 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.

  14. 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. ...

  15. Development of Glassy Carbon Blade for LHC Fast Vacuum Valve

    CERN Document Server

    Coly, P

    2012-01-01

    An unexpected gas inrush in a vacuum chamber leads to the development of a fast pressure wave. It carries small particles that can compromise functionality of sensitive machine systems such as the RF cavities or kickers. In the LHC machine, it has been proposed to protect this sensitive equipment by the installation of fast vacuum valves. The main requirements for the fast valves and in particular for the blade are: fast closure in the 20 ms range, high transparency and melting temperature in case of closure with beam in, dust free material to not contaminate sensitive adjacent elements, and last but not least vacuum compatibility and adequate leak tightness across the blade. In this paper, different designs based on a vitreous carbon blade are presented and a solution is proposed. The main reasons for this material choice are given. The mechanical study of the blade behaviour under dynamic forces is shown.

  16. Observations of dynamic stall on Darrieus wind turbine blades

    Energy Technology Data Exchange (ETDEWEB)

    Fujisawa, N.; Shibuya, S. [Department of Mechanical and Production Engineering, Niigata University, 8050 Ikarashi 2, 950-2181 Niigata (Japan)

    2001-02-01

    Flow field around a Darrieus wind turbine blade in dynamic stall is studied by flow visualization and particle image velocimetry (PIV) measurement in stationary and rotating frames of reference. The experiment is carried out using the small-scale Darrieus wind turbine in a water tunnel. The unsteady nature of the dynamic stall observed by the flow visualization is quantitatively reproduced in the instantaneous velocity distributions by PIV measurement, which describes the successive shedding of two pairs of stall vortices from the blade moving upstream. The mechanism of dynamic stall is due to the successive generation of separation on the inner surface of the blade followed by the formation of roll-up vortices from the outer surface. Although the qualitative nature of the dynamic stall is independent of the tip-speed ratios, the blade angle for stall appearance and the growth rate of the stall vortices are influenced by the change in tip-speed ratios.

  17. Non-invasive dynamic measurement of helicopter blades

    Science.gov (United States)

    Serafini, J.; Bernardini, G.; Mattioni, L.; Vezzari, V.; Ficuciello, C.

    2017-08-01

    This paper presents the development and the application on helicopter blades of a measurement system based on FBG strain gauges. Here, the main goal is the structural characterization of the main rotor blades, with the aim of showing the potentialities of such a system in blades quality check applications, as well as in the development of structural health monitoring and rotor state feedback devices. The device has been used in both non-rotating and rotating tests, and does not require the presence of slip rings or optical joint since it is completely allocated in the rotating system. It has been successfully applied to characterize the frequency response of blades lead-lag, flap and torsion deformations, up to 250 Hz.

  18. CMC blade with pressurized internal cavity for erosion control

    Science.gov (United States)

    Garcia-Crespo, Andres; Goike, Jerome Walter

    2016-02-02

    A ceramic matrix composite blade for use in a gas turbine engine having an airfoil with leading and trailing edges and pressure and suction side surfaces, a blade shank secured to the lower end of each airfoil, one or more interior fluid cavities within the airfoil having inlet flow passages at the lower end which are in fluid communication with the blade shank, one or more passageways in the blade shank corresponding to each one of the interior fluid cavities and a fluid pump (or compressor) that provides pressurized fluid (nominally cool, dry air) to each one of the interior fluid cavities in each airfoil. The fluid (e.g., air) is sufficient in pressure and volume to maintain a minimum fluid flow to each of the interior fluid cavities in the event of a breach due to foreign object damage.

  19. 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

  20. Pressure coefficient evolutions on the blades of a Savonius rotor

    Energy Technology Data Exchange (ETDEWEB)

    Chauvin, A.; Guignard, S. [UMRR 7343, Marseilles (France). Lab. IUSTI; Kamoun, B. [Faculte des Sciences de Sfax (Tunisia). Lab. de Physique

    2012-07-01

    Measurements of the pressure field distribution on the blades of a vertical axis Savonius wind machine are presented. The rotor used in the wind tunnel is a two blades cylindrical shape with a central gap. Pressure gauges are placed on each side of a blade, so the pressure jumps between intrados and extrados of a blade during a whole rotation are drawn. In the static configuration, the machine is disposed at various incidences. The determination of pressure jumps allows to calculate the static torque of the machine versus the incidence angle. In the dynamic situation the machine is rotating at various frequencies and gauges signals are varying dynamically of course with the incidence. The dynamic torque coefficient is calculated. Evolutions of the starting torque and starting conditions are then described and dynamic effects on torque evolution are presented. (orig.)