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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
301

Výpočtová analýza napjatosti turbinové lopatky / Computational analysis the state of stress of turbine blade

Klement, Jan January 2011 (has links)
This diploma thesis continues to the Ing. Damborský work and deals with strain-stress and dynamic analysis of the steam turbine blade. This blade is part of the last row of low pressure level of steam turbine. Computational analysis has been performed in first part using FEM. After that follows a modal analysis for the blade without residual stress as well as for the blade affected by heat treatment. Main goal is to obtain whether the state of stress is in the crack initiation area is influenced by thermal treatment. This problem was solved by computational simulation in commercial software Ansys 11.0.
302

Energetická bilance tvarů kmitání lopatky poslední řady parní turbíny / Energy balance the blade of the last stage steam turbine

Horák, Petr January 2012 (has links)
Created methodology for calculating the potential deformation energy parts is described in this thesis. Calculation method uses the outputs of modal analysis, which is performed using computational modelling. The potential deformation energy parts are calculated for three cases. Two benchmark problems and one case of blade model. Blade geometry is received by 3D scanning and reconstruction of given specimen. Results of the potential deformation energy parts calculations are analyzed and conclusions are formulated.
303

Komplexní strukturální analýza kompresorového kola s využitím MKP / Comprehensive structural analysis of compressor wheel using FEM

Chromek, Lukáš January 2012 (has links)
This thesis explores the utilization of FEM software ANSYS in the analysis of the real blade wheel of a radial compressor used in small turbine aviation motors. This apparatus is made by První brněnská strojírna a.s., and its detached site in Velká Bíteš where it has the aviation engineering division. The aim of this thesis is a comprehensive blade wheel analysis composed of several steps. These steps include static and elasto-plastic strength analysis, which describes stress distribution and its assessment from the perspective of boundary conditions of elasticity during the use of the Hooke and the non-linear model of the material. Another step is dynamic analysis; in this case modal analysis, which describes the frequencies and its waveforms. The last part of the thesis contains thermal analysis while considering stationary and non-stationary thermal field. The analysis is then transformed into thermal-stress coupled analysis, which describes stress distribution resulting from thermal expansion of the material. The thesis follows the process of calculation simulations that are used during the design of a real impeller, thus before the creation of a prototype that undergoes real experiments.
304

Deformačně-napěťová analýza axiálního turbínového kola turbovrtulového motoru / Stress-strain analysis of the axial turbine of turboprop engine

Kolárik, Matej January 2014 (has links)
This diploma thesis deals with a creation and subsequent analysis of the computational model of the turboprop engine's turbine designed by Prvá Brněnská Strojírna Velká Bíteš. The computational model is created and solved in the finite element model system ANSYS. A cyclic symmetry is taken into account during the solution. The static analysis of the turbine was carried out in objective to quatify prestress effects which are caused by a rotation, higher temperature and an excitation from stator blades. These prestress effects were used in the modal analysis of the turbine. Harmonic analysis were calculated to simulate an operation conditions and a resonance state. The results of these analysis indicate that the higher temperature has the biggest impact on the properties of the turbine. It is also shown, that during the operation of the engine the turbine runs in the mode which is not even close to the resonance state.
305

Stanovení dynamických vlastnosti rotoru turbodmychadla / Determination of Turbocharger Rotor Dynamic Properties

Blaha, Adam January 2014 (has links)
This diploma thesis deals with dynamic behaviour of a turbocharger rotor. The subject is a stock turbocharger for commercial vehicles. The research will be mentioned in the first part of the thesis as well as methods of processing. The second, practical part is divided into two divisions. They are both experimental and computational. The aim is finding of rotordynamic behaviour by an experiment and its comparing with a computational model in ANSYS software. Modal and harmonic analysis of a free and fixed subject will be used by both experiment and evaluation. The subject will be fixed where bearings are located during harmonic analysis. All the experimental results will be processed with mathematical and physical methods like FFT analysis or Campbel diagram. There will be two main types of computational models to choose among. These models will be analyzed in detail. The goal of the thesis is to reach results from ANSYS as close as possible with the experimental testing. This includes finding correct material and physical properties, right choice of mesh and right boundary conditions. At the same time the CPU time compared to the model complexity and results accuracy will be considered in a comparison with data obtained by the experiment.
306

Aeroelastická analýza konstrukce letounu VUT 081 Kondor / VUT 081 Kondor aircraft aeroelastic analysis

Talanda, Tomáš January 2014 (has links)
This master thesis deals with VUT~081~Kondor aircraft flutter analysis. This aircraft is being designed at the Institute of Aerospace Engineering, Faculty of Mechanical Engineering, Brno University of Technology. The thesis contains detailed aircraft description, natural frequency and normal modes computation as well as aircraft structure flutter analysis and critical flutter velocity determination. Some structure improvement recommendations have been given in order to increase the critical flutter velocity and to fulfil the CS-VLA regulation requirements.
307

Porovnání modálních vlastností oběžných kol parní turbíny s různými délkami lopatek / Comparison of modal properties of steam turbine impeller with blades of different lengths

Havlásek, Michal January 2015 (has links)
The presented master's thesis deals with the safety assessment of several variants of the impeller with different blades length. The motivation for creating this thesis is to find the solution of the problem situation which is characterized by the breakdown of the steam turbine impeller with blades length of 30mm. As confirmed in this thesis, the impeller with blades length of 30mm is operated in the resonance. Likewise, according to the technical standard ČSN EN ISO 10437 its operation is not safe. As the correction action for the problem situation solving is proposed the prolongation of the impeller's blades. The safety is detected for six variants of impeller with dierent blades length. For each variant, there is executed a modal analysis and its results are drawn up into the Campbell diagram. On the basis of this diagram, the safety of individual components is evaluated. The last part of the masters thesis concerns with the examination of the influence of blades length on the modal properties of the impeller.
308

Analýza frekvenčního naladění lopatek oběžného kola parní turbíny / Frequency analysis of the blades of the steam turbine impeller

Krejčí, Jaroslav January 2015 (has links)
The master thesis deals with modal analysis of the blade of the steam turbine impeller. This analysis is made to find the frequency response of the blade in order to predict the dangerous speeds of the steam turbine. At first the problem situation is described. Than follows the research study which is focused on steam turbines and especially on the rotor dynamic systems and the way to ascertain the modal parameters of the dynamic system by experiment. After that the solution of the problem is performed by computational modelling. The results of the computation are analyzed in detail for different variations of the blade length by Campbell diagram. A graph showing dependency between dangerous speeds of the turbine and the blade length is made out of the results. Then the results are verified by experiment and the coefficients of proportional damping are specified. In conclusion the optimal variation of the blade length for the given operational state is determined.
309

Numerische Umsetzung der Galbrun-Gleichung zur Modalanalyse strömender Medien in Außenraumproblemen unter Einsatz finiter und infiniter Elemente

Retka, Stefanie 15 June 2012 (has links)
In der vorliegenden Arbeit wird ein Programmcode zur numerischen Modalanalyse dreidimensionaler Fluide in komplexen akustischen Systemen, speziell in Resonatoren, entwickelt. Mit diesem Code ist es möglich, turbulente Strömungen im Rahmen der Modalanalyse zu berücksichtigen. Hierzu wird ein realistisches Strömungsprofil, ermittelt mithilfe eines 3D-Navier-Stokes-Lösers, verwendet. Der Hauptteil der Arbeit befasst sich mit der Herleitung der für die Berechnung notwendigen Galbrun-Gleichung und deren Aufbereitung zur numerischen Analyse. Für die numerische Umsetzung kommt die Methode der finiten Elemente in Verbindung mit komplex konjugierten, infiniten Astley-Leis Elementen zur Anwendung. Die infiniten Elemente werden genutzt, um in den betrachteten Außenraumproblemen die Abstrahlung in das Fernfeld abzubilden. Nach der Anwendung des entwickelten Programmcodes auf einfachere Modelle erfolgen Untersuchungen zur Intonation einer Blockflöte. Hierzu wird das Fluid innerhalb und im Nahfeld des Instruments unter Berücksichtigung des turbulenten Strömungsprofils, welches sich beim Spielen der Blockflöte ausbildet, betrachtet. Im Ergebnis stehen die Eigenwerte des Instruments in Abhängigkeit von der gewählten Griffkombination. Zur Evaluierung der Ergebnisse und zur Untersuchung des Einflusses der Strömung auf den Klang erfolgt der Vergleich mit den exakten Eigenfrequenzen. Die Galbrun-Gleichung wurde bereits von anderen Autoren untersucht und auf akustische Problemstellungen angewendet. Im Rahmen dieser Arbeit erfolgt jedoch erstmalig die Anwendung der Galbrun-Gleichung auf Eigenwertprobleme. Darüber hinaus sind der Autorin keine Arbeiten bekannt, die sich mit dreidimensionalen Modellen befassen. In der vorliegenden Arbeit werden somit erstmals komplexe dreidimensionale Modelle unter Anwendung der Galbrun-Gleichung untersucht.
310

Development and Analysis of Nordic32 Power System Model in PowerFactory

Peppas, Dimitris January 2008 (has links)
The present work deals with the implementation of the test system Nordic32 proposed by Cigre task force 38-02-08. This test system which consists of 32 buses is a representation of the Swedish transmission and is suitable for the simulation of transient stability and long term dynamics. This work provides a detailed description about the steps followed to create both the static part of the system for load flow calculations and the controllers that the generators are equipped with. Furthermore, the thesis closes with a basic study concerning the modal analysis and the voltage stability of the system revealing some weaknesses that need further examination.

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