Tesis sobre el tema "Turbine blade vibration"
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Esu, Ozak O. "Vibration-based condition monitoring of wind turbine blades". Thesis, Loughborough University, 2016. https://dspace.lboro.ac.uk/2134/21679.
Texto completoKelen, Peter. "A finite element analysis of the vibration characteristics of rotating turbine blade assemblies". Thesis, University of Surrey, 1985. http://epubs.surrey.ac.uk/2098/.
Texto completoFlood, Robert C. "Vibrations of an isolated wind turbine blade using the finite element method". Thesis, Virginia Polytechnic Institute and State University, 1986. http://hdl.handle.net/10919/91089.
Texto completoM.S.
Cigeroglu, Ender. "Development of microslip friction models and forced response prediction methods for frictionally constrained turbine blades". Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1181856489.
Texto completoTartibu, Kwanda. "A simplified analysis of the vibration of variable length blade as might be used in wind turbine systems". Thesis, Cape Peninsula University of Technology, 2008. http://hdl.handle.net/20.500.11838/1244.
Texto completoThis work was supported by the Research office of CPUT.
Zdunek, Agnieszka Izabela. "Prediction of natural frequencies of turbine blades for turbocharger application : an investigation of the finite element method, mathematical modelling and frequency survey methods applied to turbocharger blade vibration in order to predict natural frequencies of turbocharger blades". Thesis, University of Bradford, 2014. http://hdl.handle.net/10454/7328.
Texto completoVan, Dyke Jason. "Modeling Behaviour of Damaged Turbine Blades for Engine Health Diagnostics and Prognostics". Thèse, Université d'Ottawa / University of Ottawa, 2011. http://hdl.handle.net/10393/20312.
Texto completoTournu, Erik. "Modélisation stochastique du comportement dynamique non linéaire d'un ailetage de turbine : application à une poutre avec contact oblique". Vandoeuvre-les-Nancy, INPL, 1996. http://www.theses.fr/1996INPL118N.
Texto completoHorák, Petr. "Energetická bilance tvarů kmitání lopatky poslední řady parní turbíny". Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2012. http://www.nusl.cz/ntk/nusl-230409.
Texto completoCantoni, Lorenzo. "Load Control Aerodynamics in Offshore Wind Turbines". Thesis, KTH, Kraft- och värmeteknologi, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-291417.
Texto completoPå grund av ökningen av rotorstorleken hos horisontella vindturbiner (HAWT) under de senaste 25 åren, en design som har uppstod för att uppnå högre effekt, måste alla vindkraftkomponenter och blad stå emot högre strukturella belastningar. Detta uppskalningsproblem kan lösas genom att använda metoder som kan minska aerodynamiska belastningar som rotorn måste tåla, antingen med passiva eller aktiva styrlösningar. Dessa kontrollanordningar och tekniker kan minska utmattningsbelastningen på bladen med upp till 40 % och därför behövs mindre underhåll, vilket resulterar i viktiga besparingar för vindkraftsägaren. Detta projekt består av en studie av lastkontrolltekniker för havsbaserade vindkraftverk ur en aerodynamisk och aeroelastisk synvinkel, i syfte att bedöma en kostnadseffektiv, robust och pålitlig lösning som kan fungera underhållsfri i tuffa miljöer. Den första delen av denna studie involverar 2D- och 3D-aerodynamiska och aeroelastiska simuleringar för att validera beräkningsmodellen med experimentella data och för att analysera interaktionen mellan fluiden och strukturen. Den andra delen av denna studie är en bedömning av de ojämna aerodynamiska belastningarna som produceras av ett vindkast över bladen och för att verifiera hur en bakkantklaff skulle påverka de aerodynamiska styrparametrarna för det valda vindturbinbladet.
Breslavsky, D. V., O. K. Morachkovsky y N. V. Shyriaieva. "Nonlinear vibrations and long-term strength of turbine blades". Thesis, National Technical University "Kharkov Polytechnic Institute", 2010. http://repository.kpi.kharkov.ua/handle/KhPI-Press/41290.
Texto completoDamborský, Petr. "Výpočtová a experimentální analýza napjatosti turbinové lopatky". Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2009. http://www.nusl.cz/ntk/nusl-228577.
Texto completoAbouhnik, Abdelnasser Abouzid. "An investigation into vibration based techniques for wind turbine blades condition monitoring". Thesis, Manchester Metropolitan University, 2012. http://e-space.mmu.ac.uk/313141/.
Texto completoOlafsson, Sveinn V. "Random vibrations of bladed-disk assembly under cyclostationary excitation". Thesis, Virginia Tech, 1988. http://hdl.handle.net/10919/43261.
Texto completoMaster of Science
Lackner, Matthew 1980. "Vibration and crack detection in gas turbine engine compressor blades using Eddy current sensors". Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/28895.
Texto completoIncludes bibliographical references (p. 97).
(cont.) in the ECS signal, no definitive method for sensing blade vibration using an ECS has yet been developed.
High cycle fatigue (HCF) cracks generated by compressor blade vibrations are a common source of failure in gas turbine engines. Current methods for crack detection are costly, time consuming, and prone to errors. In-situ blade vibration detection would help operators avoid critical engine speeds, and help infer the presence of cracks via a change in the mode of a blade. Blade vibrations can be detected using non-contacting sensors like optical sensors, or contacting sensors like strain gauges. These methods have drawbacks that make them poorly suited for installation in a gas turbine engine. Eddy Current Sensors (ECS) have numerous advantages over other vibration detection methods. This thesis aims to use ECS's for vibration detection. Testing was performed in a spin pit rig in the Gas Turbine Lab at the Massachusetts Institute of Technology. The rig contained a rotor on which three test blades spun, and strain gauge and ECS data were extracted from the rig. Magnet arrays were used to provide an excitation force to the blades, causing them to vibrate as they were spinning. Force hammer testing was used to determine the resonant frequencies and mode shapes of the test blades, as well as transfer functions from the strain gauges to the blade tip acceleration. These transfer functions allowed for independent knowledge of the blade vibration behavior. The case of a cracked blade was also considered. Estimates were performed to determine the proper location and length of a crack in the test blade. A 10 mm edge crack was created in a test blade. The crack was found to lower the resonant frequency of the first torsion mode of the blade by 0.2%, and to alter the transfer function between strain and tip acceleration. While some evidence of the blade vibration appears
by Matthew Lackner.
S.M.
Agnese, Fabio. "Enhanced vibration damping materials and structures for wind turbine blades inspired from auxetic configurations". Thesis, University of Bristol, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.653091.
Texto completoHoell, Simon. "Optimal feature projections for enhanced vibration-based damage identification with an application to wind turbine blades". Thesis, University of Aberdeen, 2016. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=231272.
Texto completoLošák, Petr. "Optimalizace modálního tlumení lopatek vysokotlakých stupňů parních turbín". Doctoral thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2011. http://www.nusl.cz/ntk/nusl-233951.
Texto completoMyhre, Mikkel. "Numerical investigation of the sensitivity of forced response characteristics of bladed disks to mistuning". Licentiate thesis, KTH, Energy Technology, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-1639.
Texto completoTwo state of the art finite element reduction techniquespreviously validated against the direct finite element method,one based on classical modal analysis and another based oncomponent mode synthesis, are applied for efficient mistunedfree vibration and forced response analysis of several bladeddisk geometries. The methods are first applied to two testcases in order to demonstrate the differences in computationalefficiency as well as to validate the methods againstexperimental data. As previous studies have indicated, nonoticeable differences in accuracy are detected for the currentapplications, while the method based on classical modalanalysis is significantly more efficient. Experimental data(mistuned frequencies and mode shapes) available for one of thetwo test cases are compared with numerical predictions, and agood match is obtained, which adds to the previous validationof the methods (against the direct finite element method).
The influence of blade-to-blade coupling and rotation speedon the sensitivity of bladed disks to mistuning is thenstudied. A transonic fan is considered with part span shroudsand without shrouds, respectively, constituting a high and alow blade-to-blade coupling case. For both cases, computationsare performed at rest as well as at various rotation speeds.Mistuning sensitivity is modelled as the dependence ofamplitude magnification on the standard deviation of bladestiffnesses. The finite element reduction technique based onclassical modal analysis is employed for the structuralanalysis. This reduced order model is solved for sets of randomblade stiffnesses with various standard deviations, i.e. MonteCarlo simulations. In order to reduce the sample size, thestatistical data is fitted to a Weibull (type III) parametermodel. Three different parameter estimation techniques areapplied and compared. The key role of blade-to-blade coupling,as well as the ratio of mistuning to coupling, is demonstratedfor the two cases. It is observed that mistuning sensitivityvaries significantly with rotation speed for both fans due toan associated variation in blade-to-blade coupling strength.Focusing on the effect of one specific engine order on themistuned response of the first bending modes, it is observedthat the mistuning sensitivity behaviour of the fan withoutshrouds is unaffected by rotation at its resonant condition,due to insignificant changes in coupling strength at thisspeed. The fan with shrouds, on the other hand, shows asignificantly different behaviour at rest and resonant speed,due to increased coupling under rotation. Comparing the twocases at resonant rotor speeds, the fan without shrouds is lessor equally sensitive to mistuning than the fan with shrouds inthe entire range of mistuning strengths considered.
This thesisscientific contribution centres on themistuning sensitivity study, where the effects of shrouds androtation speed are quantified for realistic bladed diskgeometries. However, also the validation of two finite elementreduction techniques against experimental measurementsconstitutes an important contribution.
Drozdowski, Roman. "Berechnung der Schwingbeanspruchung in Radialturbinen unter Berücksichtigung realer Bauteilgeometrien". Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2012. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-83971.
Texto completoМоргун, Сергій Олександрович, Сергей Александрович Моргун y Sergii O. Morgun. "Напряженно-деформированное состояние конструктивно неоднородных лопаток турбомашин при их вибрациях". Thesis, Запорізький національний технічний університет, 2015. http://eir.zntu.edu.ua/handle/123456789/419.
Texto completoUK: Дисертація присвячена визначенню параметрів напружено-деформованого стану конструктивно неоднорідних робочих лопаток турбомашин при їх вібраціях з використанням методу скінчених елементів. Розвинуті і теоретично обґрунтовані ефективні чисельні методи для розв’язання розглянутих в дисертації задач. Досліджено вплив геометричних характеристик лопаток, фізико-механічних властивостей матеріалу, температури газового потоку на частоти та форми коливань і напружено-деформований стан робочих лопаток турбомашин. Достовірність та адекватність розроблених математичних моделей підтверджена співставленням результатів з даними, отриманими з використанням пакету програм ANSYS та експериментально. EN: The thesis is devoted to the non homogeneous cooled single turbine blades and strain-deformed state parameters under vibration load by means of finite elements method usage. The effective numerical methods for the foregoing problems solution are also developed and theoretically approved. The turbine blades geometrical characteristics, their material physical and mechanical state and the gas flow temperature influence on their oscillation forms and frequencies, and strain-deformed state has been researched. The results of the research have been adopted by the obtained results comparison with the ANSYS program package’s solutions and experimental data. RU: Диссертация посвящена определению параметров напряженно-деформированого состояния конструктивно неоднородных лопаток турбомашин при их вибрациях с использованием метода конечных элементов. Приведена постановка и обоснование задач динамического поведения рабочих лопаток турбомашин. Развиты и теоретически обоснованы эффективные численные методы для решения рассмотреных в дисертации задач. Построены уточненные математические модели свободных и вынужденных колебаний, а также напряженно-деформированного состояния, позволяющие адекватно описывать динамическое поведение конструктивно неоднородных рабочих лопаток. Уравнения движения лопаток получены с использованием вариационного принципа Лагранжа II рода. Выполнен анализ сходимости полученных решений. Получены результаты количественного и качественного характера для лопаток с конструктивными неоднородностями, которые характеризуют особенности их поведения при вынужденных колебаниях, вызванных воздействием переменной газодинамической силы. Исследовано влияние геометрических характеристик лопаток, физико-механических свойств материала, температуры газового потока на частоты и формы колебаний и напряженно-деформированное состояние рабочих лопаток турбомашин. Достоверность и адекватность разработанных математических моделей подтверждена сопоставлением полученных результатов с данными, полученными с использованием пакета программ ANSYS и экспериментальным путем. Экспериментальные исследования частот и форм колебаний, как охлаждаемых, так и неохлаждаемых лопаток турбомашин проводились методом голографической интерферометрии. Параметры напряженно-деформированного состояния лопаток определялись на специальном вибровоздушном стенде с применением метода тензометрирования.
Janicki, Grzegorz, Antonios Pezouvanis, Byron A. Mason y Kambiz M. Ebrahimi. "Turbine blade vibration measurement methods for turbocharges". 2014. http://hdl.handle.net/10454/9842.
Texto completoThis paper presents and compares the most important and often used methods to measure turbine blade vibrations: use of strain gauges and telemetry system which is an intrusive method or, on the other site. The Blade Tip Timing (BTT) method known as Non-Intrusive Stress Measurement (System) NSMS. Both methods have advantages and disadvantages which are described below. This paper focused on synchronous vibrations, which are more important in terms of turbine blades fatigue prediction and design optimization.
Li, Shih-Hsing y 李志興. "Vibration Mode Study of Small Wind Turbine Plastic Blade". Thesis, 2012. http://ndltd.ncl.edu.tw/handle/16708698791039183048.
Texto completo中華科技大學
飛機系統工程研究所
100
ABSTRACT Energy consumption becomes more and more important in the future of our live. The green energy of wind power is relatively much attention. Especially, the composite material small and medium-sized wind turbine blades take a major part in the domestic wind power market. In here, our research is concentrate at small injection molding of composite wind blades as research material. There are five different plastics are going to studies such as: Poly Butylene Terephathalate referred to as PBT, Poly phenylene sulfide referred to as PPS, polypropylene referred to as PP, NYLON and Poly Carbonate referred to as PC . Those five plastics will containing 40% fiber materials explore in the structure of mode shapes to study and compare. The material plastic blades structural strength is going to apply to the American Air-X 400Won superiority of the small wind turbines. On the other hand, research methods are going tap the test module to collect the leaf structure shapes and establish the modal database for numerical analysis. Beside, the MATLAB numerical calculation software and the ANSYS finite element analysis software modeling were used to analyze and compare the experiment results. The results will discuss of blades applicability as well as flaws in the process. Finally, the bending test and vibration database validation will compare the experimental design with the composite wind turbine blades of the basic theory. According to the origin design shape, the results we funded the most suitable material is PPS from five kinds of materials. For the PPS mechanical properties can be the less temperature sensitivity and the small knot vibration to system. During the procedure of injection, molding structural porosity defects on the small wind blades and micro-structural strength will be future related research. Keywords: Plastic Blade Vibration Mode, Vibration Mode, Vibration Testing, Modal Database.
Chern, Chern-Kao y 程國城. "Analyses of Stresses and Vibration for the Turbine Blade". Thesis, 2007. http://ndltd.ncl.edu.tw/handle/58939131222393926771.
Texto completo華梵大學
機電工程研究所
95
The aim of this paper is to analyze the static stress and vibration characteristics for the steam turbine blades using the finite element method. The turbine blades are vulnerable to induce creep deformation and crack defects under long term operation at high temperature. The strength of blades must be large enough to prevent the yielding and fatigue. In the meanwhile, the prevention of vibration resonance for turbine blades is important. The turbine blade’s model was constructed by using the graphic software, Solid Works. The finite element software, ANSYS, was employed to calculate the structural stress, natural frequency, and mode shape. The stress distributions of the cracked-blade subjected to the differential steam pressure and rotational motion were obtained to discuss the influence of the crack contained in the blade. It was found that the turbine blade will yield under the high rotation speed. Finally, the natural frequency and vibration modes were obtained to reveal the influence of the crack. It was found that the natural frequency for the cracked-blade is less than that of the blade free from the crack defect.
Babawarun, Tolulope. "Improvement of vibration behaviour of small-scale wind turbine blade". Diss., 2020. http://hdl.handle.net/10500/27607.
Texto completoMechanical and Industrial Engineering
M. Tech. (Electrical and Mining Engineering)
Hsiung, Wan-Ying y 熊婉贏. "Vibration Analysis and Damage Detection of a Research-scale Wind Turbine Blade". Thesis, 2014. http://ndltd.ncl.edu.tw/handle/87676210092876441145.
Texto completo國立臺灣大學
土木工程學研究所
102
The objective of this study was to validate modal analysis, system identification and damage detection of small-scale rotating wind turbine blades in the laboratory and in the field. Here, wind turbine blades were instrumented with accelerometers and strain gages, and data acquisition was achieved using a prototype wireless sensing system. In the first portion of this study conducted in the laboratory, sensors were installed onto metallic structural elements that were fabricated to be representative of an actual wind blade. In order to control the excitation (rotation of the wind blade), a motor was used to spin the blades at controlled angular velocities. The wind turbine was installed on a shaking table for testing. Under the circumstance of the couple of rotating wind turbine blade and tower with base excitation to measure the signals of different rotation speed. On the other hand, the second part of this study which is field experiment utilized a small-scale horizontal axis wind turbine system mounted on the rooftop of a building at University of California, Davis. The model of this wind turbine is Bergey Windpower XL.1. Compared to the lab tests, the main difference was that the field tests relied on actual wind excitations (as opposed to a controlled motor). In laboratory test, the turbine blade divided into two cases, undamaged and damaged blades. Take two loose bolts connection in one of the turbine blade as damaged cases and use damage index to identify the damage occurrence in blade. In addition, the raw data from both laboratory tests and field tests were analyzed by signal processing and system identification techniques for deriving the model response of the blades. The Multivariate Singular Spectrum Analysis (MSSA), Covariance-driven Stochastic Subspace Identification method (SSI-COV) and Data-driven Subspace Identification method (SI-DATA) were used to identify the dynamic characteristics of the system. These above experiments confirmed that dynamic characterization of rotating wind turbines system was feasible, and the results will guide future wind turbine monitoring studies.
Nanami, Norimichi. "Vibration and Structural Response of Hybrid Wind Turbine Blades". 2010. http://hdl.handle.net/1969.1/ETD-TAMU-2010-12-8735.
Texto completoHuang, Yu-Ting y 黃昱婷. "Image based vs vibration based analysis of a research scale wind turbine blade". Thesis, 2014. http://ndltd.ncl.edu.tw/handle/60646723330492401538.
Texto completo國立臺灣大學
土木工程學研究所
102
The objective of this study was to validate modal analysis and system identification of an operating, small-scale, wind turbine system in the laboratory. In general, wind turbine blades were instrumented with accelerometers and strain gages, and data acquisition was achieved using a prototype wireless sensing system. In this study, an experiment was designed to control the rotation of wind turbine blades in the lab. In order to control the excitation (rotation of the wind blade), a motor was used to spin the blades at controlled angular velocities. Sensors were installed onto two different representative and metallic wind blades (i.e., damaged versus undamaged blade). Data measured by the contact sensors (accelerometers and strain gages) and the photographic images (camera) were recorded while the blade was operated at different speeds. First, to analyze the displacement/motion of the turbine blade, a photogrammetric approach was used. After 3D calibration of the imaging system, 3D positions are calculated using a stereo triangulation technique and digital images taken to track the 3D motion of the blade. Image measurement error induced by image analysis error and camera synchronization error was discussed. Second, the dynamic characteristics of the rotating blade were investigated. The Rodrigues’ rotation was applied to the data to extract the vibration signal due to rotation. Separation of the turbine blade natural frequencies and the rotating frequency can successfully be carried out. From which the residual signal can be used to identify the dynamic characteristics of turbine blade. Dynamic characteristic of undamaged and damage turbine blade was investigated.
Jheng, Siang-Jyun y 鄭翔駿. "The Measurement Applications of Image Analysis at Structure Vibration Properties of Wind Turbine Blade". Thesis, 2016. http://ndltd.ncl.edu.tw/handle/8fve6w.
Texto completo國立臺北科技大學
土木工程系土木與防災碩士班
105
In the measurement of wind turbine blade vibration, various restrictions on the installation of contact sensors. Such as the signal line is easy to be pulled, wireless sensor power supply problems will cause measurement inconvenience. Although the image measurement technology is maturing, it’s not easy to measure small vibrations of fan blades in a wide range of rotation motion. In addition, the experimental processes still have a lot of irresistible external factors, such as light instability caused by experimental data is full of all kinds of noise. The noise is even greater than the vibration of the blade. The condition make the subsequent signal analysis is not easy. In order to analyze the measured vibration data, this study will capture the image data to do image processing and signal analysis. In the image analysis, this study uses camera image calibration, template matching, triangulation, coordinate transformation and so on. In the study, the frequency of the vibration of the target structure was found by filtering, Singular Spectrum Analysis (SSA) and Wavelet Packet Transform(WPT), filter out noise to find the frequency of vibration of the target structure and use these data to achieve the effect of structural health monitoring. The study also found that the use of image analysis will appear signals of multiple frequencies. And the study considers that it is not the phenomenon of structural vibration. This paper presents these multiple frequency phenomena and explains the cause of the multiplication phenomenon.
Wang, Min-Jou y 王明州. "Analyze the Suppression Effect of Turbine Blade Vibration by Flywheel Damper Using the Finite Element Method". Thesis, 2004. http://ndltd.ncl.edu.tw/handle/02409378375008481460.
Texto completo南台科技大學
電機工程系
92
Considering the accuracy of frequency and stress, FEM is superior then lumped parameter dynamic program. However, FEM alone cannot obtain the blade overload under power fault. The dynamic simulating torsional response had been proved quite accurate by the experiment, but for the extended part of the blade, the credibility is relatively poor since the model is simple and crude. This thesis adopts torsional response simulation to get the analytic information which is employed by FEM and the mesh analysis of the blade. This thesis is to establish an appropriate mechanical system model for the rotor parts and the final three stages blades of a low-pressure turbine. It makes use of the verified dynamic program to simulate the torsional vibration of turbine-generator in the severe power fault (line-to-line short circuit). It explores the suppress effect of blade fatigue induced by vibration as the incident happens owing to the variation of the inertia of “Flywheel Damper” installed on the coupling. The Finite Element Method is aided to make the stress analysis of turbine blade details. On the basis of the finite element analysis software ANSYS. Firstly, we simulate the steam thrust added on last stage blades at ordinary time and probe which part on last stage blade bear the maximum force. Secondly, the vibration torque due to line-to-line fault has been added on the shaft, and probes the last stage blades under stress condition. Finally, the same finite element analysis software ANSYS is adopted to compare the stress condition of the blade with the flywheel damper of variant inertia. The research aimed on designing proper equipment to reduce vibration and limit vibration torque under network fault in order to lengthen the result of life-span to charge. Moreover, the utilization of 3D blade to simulate and find out which part bear the maximum strength is also good for overhaul consulting at ordinary times. Furthermore, enormous damages can be prevented. Keywords:FEM, turbine-generator, final three stages blades
Ming, Chen Hua y 明振華. "Vibration Analysis of Cracked Turbine Blades". Thesis, 1998. http://ndltd.ncl.edu.tw/handle/60080276945303135487.
Texto completo國立中央大學
機械工程學系
86
This paper studies the dynamic behavior and vibration modes of cracked turbine-blade through numerical simulation by transfer method . Although the usual turbine blades have complex geometric shape , such as a pre-twisted angle , width and depth , which all change with the length of blade . But the precision of blade's simulation by general beams has been proved well in many papers .Therefore , Timoshenko contiuous beam is selected in the present thesis . Besides , blade is often connected with a flexible disk which induces the vibration of blade . Hence the disk's influences in vibration behavior of a blade are also considered in this paper . The way of crack-modeling adopts the local flexibility matrix , and then the system's governing equation is solved by transfermethod . Finally the system's natunal frequency and vibration modes can be obtained . This paper shows the influences of a crack location and the crack sizeon blade's system . The effects of transverse shear deformation , rotary inertia and the pre-twisted angle are taken into account . It is found that the crack has great influences on the dynamic characteristics of the rotating blade .
QIN, CUN y 秦純. "Vibration analysis of turbine-generator shafts and blades". Thesis, 1992. http://ndltd.ncl.edu.tw/handle/96605876665306428697.
Texto completoChang, I.-Chieh y 張奕傑. "Vibration Analysis of Rotating Vertical Axis Wind Turbine Blades". Thesis, 2011. http://ndltd.ncl.edu.tw/handle/26983033782497948789.
Texto completo國立臺灣大學
應用力學研究所
99
Wind power is the most potential source of renewable energy. There are two categories of modern wind turbines, namely horizontal axis wind turbines (HAWT) and vertical axis wind turbines (VAWT). Vertical axis wind turbines have the major benefit of operation that is independent of the wind direction. Other benefits include easier installation and lower noise radiation than the horizontal axis wind turbines. Therefore they have great potential for applications in the urban area. Nevertheless, higher efficiency is offered by a horizontal wind turbine as it has blades in perpendicular to direction of wind and hence receives more power for rotation. To ensure that the blades operate effectively, it is important that that their structure is dynamically safe when in rotation. There has been a growing interest in the investigation of free vibration characteristics of rotating beams because the topic plays an important role in the design of shafts, turbine blades, propellers and many other rotating structures. In this present paper, we use Hamilton’s principal to derive the dynamic governing equations for the rotational slender blade. We especially take rotational velocity which is a very important parameter when rotating into consideration. Theoretical natural frequencies and mode shapes for some illustrative examples are calculated and compared with the simulation of ANSYS Workbench. These results are discussed and compared with published ones, and we can predict the first few lower natural frequencies quite accurately. Vertical axis wind turbine is verified that the theoretical model can provide mechanical insight into the design of the blades. The vertical axis wind turbine blades are flexible, highly dynamic structure, with many natural modes of vibration that must be carefully analyzed to ensure the blades are dynamically stable under all operating conditions.
YI, HSIAO CHENG y 蕭振益. "The crack effects to the vibration behavior of large size turbine blades". Thesis, 2006. http://ndltd.ncl.edu.tw/handle/54238113995408615448.
Texto completo中華大學
機械與航太工程研究所
94
The purposes of this thesis are to study the crack effects to the vibration behavior of large size turbine blades. The vibration caused by the crack is not only to effect the dynamic characteristics of the blade, but also the dynamic characteristics of grouped blade system. Because grouped blade system is the periodically coupled blades system, once a crack appears in any blade of it, that will make the system to experience the vibration phenomenon, which causes the vibration energy and stress around the crack of the blade and then destroy the system﹒In this thesis, the dynamic characteristics caused by the crack effects are investigated. The equation of motions and boundary conditions are derived by Hamilton’s principle. The software MATLAB will be used to simulate the mathematical model developed in this thesis. The crack blade can be considered as two segments of blade. Crack effect is modeled as torsional spring to connect the two segments with proper compatibility conditions. Because of the special boundary conditions of grouped blade system, the cantilever modes and fixed-supported modes will be excited. Finally, the parameters of crack location, crack length and crack in the blade are considered to elucidate the dynamic behavior of the group blades. Through the combination of exploring process of the analysis, the knowledge are developed and an erected in a manner to upgrade technology in our living.
You, Kai-Siang y 游凱翔. "Non-linear vibration of blade bending and fluttering of vertical axis wind turbines". Thesis, 2013. http://ndltd.ncl.edu.tw/handle/75579716003645920511.
Texto completo國立臺灣大學
應用力學研究所
101
Vertical axis wind turbine has the benefit of operation that is independent of the direction, and less noise. In recent years there are more and more people involved in research of VAWTs. In this present paper, we adopt NACA0015 to be analysis model. Using nonlinear analysis to analyze resonance and stability of amplitude – force frequency relation of wind blade . The nonlinear term is cause by the axial force that owing to bending deformation. We start form basic theory of mechanics of materials. To find the strain potential energy and retained to the second order nonlinearity. Consider the kinetic energy of operating VAWTs. Using the Hamilton’s principle to derive the governing equation and then dimensionless the equation. Consider real condition to simplify the governing equation. Appling Galerkin’s method to equation and get the amplitude force frequency relation for different frequency. Using perturbation methods to designate the stable and unstable zones. In linear system the leading edge direction is uncouple, and the other bending direction is couple with torsion. So we first consider the bending and torsion coupling equation. In the last part of section we consider the two bending equation to compared with above. Simultaneously applied Runge-Kutta fourth order method to solve equation. And using FFT to analyze the result. Then use different method to present the result. Finally make a verification by compare the analysis and numerical result.
Li, Wen-Yang y 李文揚. "Torsional vibration analysis for wind-turbine generator blades and shafts subject to power system excitations". Thesis, 2010. http://ndltd.ncl.edu.tw/handle/40752105442035817051.
Texto completo高苑科技大學
電子工程研究所
98
Wind energy is one of the most popular and economic renewable energy generations. According to the statistics, there is about 3GW wind energy power potentially in Taiwan. If the grid-connected wind turbine generator is subjected to the network faults, the induced electromagnetic torque gives rise to torsional torque stresses on turbine drive train components, namely blades and high/low speed shafts. This project employs a single induction machine-infinite system of middle voltage level containing a fixed-speed wind turbine, in order to investigate the wind turbine torque behaviors owing to network faults. From the simulation results, it is found that all the turbine components are sensitive to unidirectional component excitation (the real power pulsation). Therefore,the worst-case impact is simulated and resulted from threephase-to-ground fault. The auto-reclosing time of circuit breaker next to wind power plant should be carefully examined in order to ensure long-term safety operation.
Huang, Chih-Fang y 黃志方. "Depressing the Torque Vibrations of Turbine Shafts and Blades by using a Mechanical Filter". Thesis, 1999. http://ndltd.ncl.edu.tw/handle/12899199264949293789.
Texto completo國立中山大學
電機工程學系
87
This thesis proposes a mechanical filter to depress the torque vibrations on turbine shafts and blades excited by power system faults. Due to the power system faults, the electromagnetic torque at system frequency produces the torsional stress to impact the turbine-generator shafts and blades. Therefore, the system frequency is designed as the resonant frequency of the mechanical filter installed between generator and rectifier in series. This thesis uses conversion methods from the mechanical elements of turbine-generator shafts and blades to the equivalent electrical network ones. The dynamic responses of low-pressure steam turbine blades can be obtained by fast computer calculation. In this thesis, our attention is concentrated on NO.3 nuclear power station generator sets (951MW) of the Taiwan Power Corporation to establish the simulation models proposed. According to the simulation results, it can be found that a mechanical filter design presents the good performance for improving the torque vibrations on turbine shafts and blades induced by the L-L-L-E and L-L faults. Also the vibration torque in most of turbine blades are dominated by the system frequency response. Therefore, the system-frequency mechanical filter could significantly improve the vibrating behaviors of blades. It is proposed to provide a good approach for reducing the torque vibrations on the turbine generator in this thesis.
Wu, Yun-Peng y 吳運鵬. "Three-degree-of-freedom system of linear vibration of blade bending and fluttering of vertical axis wind turbines". Thesis, 2012. http://ndltd.ncl.edu.tw/handle/10149293309873164243.
Texto completo國立臺灣大學
應用力學研究所
100
Compared to horizontal axis wind turbines, vertical axis wind turbines have the benefit of operation that is independent of the wind direction, lower wind speed to start operation, and less noise. The vibration of blade can be regarded as vibration of a beam. How to support the ends of the beam affect the vibration very much. In this present paper, we start from the energy method of Hamilton’s principle, derive the dynamic governing equations for the blade, which has three degree of freedom (includes bending and fluttering). The key variable to keep the three degree of freedom coupled is the distance from center of gravity to shear center, . When the cross-section of blade is symmetrical, the value of is zero, which means the three degree of freedom will decouple. We creat the model of NACA0015 small size blade. The NACA series blades are asymmetric, so we can keep the three degree of freedom coupled in calculation. We discrete the space and governing equation by finite difference method, solve the cases of simply support and fixed support, respectively. Then use ANSYS Workbench to do the modal analysis. Thus we obtain the natural frequency and mode shape of theory and simulation, respectively. The two results are similar in low frequency mode. By the way we use in this study, we can vary the natural frequency while design the blade, avoiding resonance in operation. Otherwise, we also do the modal testing of small size NACA0015, expect to compare the result of experiment and simulation. Due to the lack of experimental equipment, the boundary conditions of the modal testing can not coincide with the simulation. Finally we build an experiment process only, without data to compare with simulation.
蔡文昌. "Accurate models and control methods for the vibrations of shafts and blades of steam turbine-generators". Thesis, 1997. http://ndltd.ncl.edu.tw/handle/99901504796806341669.
Texto completoLin, Chi-Hshiung y 林祺祥. "Improving the Torque Vibrations on Shafts and Blades of a Large-scale Steam Turbine Generator Set". Thesis, 2000. http://ndltd.ncl.edu.tw/handle/90570995706992039439.
Texto completo國立中山大學
電機工程學系研究所
88
Abstract Recently, the expansion in power system capacities leads to the development of large-scale steam turbine generator units. As a result, a fault on the power system may induce large fault current and give rise to serious torque vibrations on turbine shafts and blades, which ought to be improved in order for the reliable operation of a turbine-generator system. In the thesis, countermeasures are proposed from electrical viewing-point and from mechanical viewing-point respectively. Based on electrical viewing-point, the apparatus in the generator stator side and in the rotor side respectively is applied to suppress the induced disturbing source. The high temperature superconductive fault current limiter bank introduces a large normal-state resistance to restrict the dc component of stator fault current. The choke coil acts as a low pass filter to restrict the system-frequency component of field fault current. Both of them lead to the reduction in electromagnetic torque of system-frequency and effectively improve the vibrating behavior of blades. Based on mechanical viewing-point, it is found from the electromechanical analysis that the Generator/LP-Turbine shaft stiffness and the Generator rotor inertia constant determine the responses of all turbine blades. Once the stiffness on this shaft section is reduced by replacing the rigid shaft coupling with a flexible one or the inertia constant is augmented by a system-frequency mechanical filter, the blades become intrinsically less responsive to electrical disturbances. As a result, the blades will bear less stress impact and can be designed with smaller safety factor. On the other hand, LP-turbine long blades operated in corrosive environment and underwent the statistical stress impact due to randomly distributed negative sequence current is studied also. In such situation, the blades may be subjected to corrosion fatigue and the long term effects of power system unbalance may become the cause of fatigue damage on blades though the negative sequence current is still within the limitation of generator thermo-rating. As a result, turbine blades are possibly unprotected by traditional system unbalance protection scheme. Therefore, it will depend on the operating environments and the blade materials whether such long-term stress can be neglected or not. If there is the potential of blade damage, one has to reconsider the I2 protection settings and rearrange the load distribution to limit the system unbalance.
Drozdowski, Roman. "Berechnung der Schwingbeanspruchung in Radialturbinen unter Berücksichtigung realer Bauteilgeometrien". Doctoral thesis, 2011. https://tud.qucosa.de/id/qucosa%3A25918.
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