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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.
351

Hnací ústrojí závodního Wankelova rotačního motoru / Powertrain of racing Wankel rotary combustion engine.

Blažo, Marek January 2010 (has links)
The main aim of master’s thesis was to handle the computing proposal and the construction design of the powertrain of racing Wankel rotary engine with 300 kW power output and in the case of 9000 speed per minute. On the basic of these values was made the primary design of the rotary engine, design of the eccentric shaft and rotor housing. Mechanical stress and torsional vibrations of the eccentric shaft were analyzed by using the course of indicator diagram.
352

Konstrukční studie sinusového čerpadla / Design study of sinus pump

Havlát, Pavel January 2011 (has links)
This dissertation focuses on the construction design of a sine pump. It particularly deals with loss minimisation and strives to solve problems relating to excessive wear of the scrapergate which separates suction and the delivery space. The first part of the dissertation describes a new construction variation of a sine pump and the second part deals with a more detailed study including optimisation of one variation.
353

Součinitele přestupu tepla na parou obtékaných plochách parních turbín / Heat transfer coefficient on surfaces of steam turbines

Belko, Milan January 2013 (has links)
This thesis in introductory part aims to analyze the available literature on the heat transfer coefficient in labyrinth seals and rotating discs of steam turbines. The available experiment studies were processed to summarize heat transfer coefficients on the rotating parts of the turbine. Then, this thesis specifies a design calculation to determine the heat transfer coefficient in selected parts of the turbine, exercisable for specific geometric and operating parameters. The outcome of this work is simulation of rotor dilation of operating steam turbine in the program Ansys during cold start of turbine.
354

Dynamika rotoru turbodmychadla s kluznými ložisky na bázi MBS / Dynamics of Turbocharger Rotor using Slide Bearings based on MBS

Hromádka, Adam January 2015 (has links)
The first part of the thesis describes construction of turbochargers. The next chapter summarizes currently used methods to solve dynamics of vehicle turbocharger´s rotor. Build-up of the model of a rotor and substitution of a joint with a bearing is appended with advantages and disadvantages. Practical part of the thesis focusses at analyse of a specific rotor of turbocharger with use of MBS. Output of the analyse are rotor´s vibrations. Last chapter complains methods to improve the model.
355

Návrh ložisek turbodmychadla pro nízkoviskózní oleje / Design of Turbocharger Bearing for Low Viscosity Oils

Plánka, Jakub January 2016 (has links)
The first part of the thesis describes journal bearings characteristics, their function and lubrication. The second part of the thesis is about a rotor-dynamics issue and how to use numerical and experimental methods for verification of a new bearing design. The practical part of the thesis is focused on analyse a current design of bearings in MBS. In the last part has been made and verified a new bearing design.
356

Effect of clocking on unsteady rotor blade loading in a low-speed axial compressor at design and off-design operating conditions

Jia, H-X, Xi, G., Müller, L., Mailach, R., Vogeler, K. 03 June 2019 (has links)
This paper presents the results of stator clocking investigations at a design point and an operating point near the stability limit in a low-speed research compressor (LSRC). The unsteady flow field of the LSRC at several clocking configurations was investigated using a three-dimensional unsteady, viscous solver. The unsteady pressure on the rotor blades at midspan (MS) was measured using time-resolving piezoresistive miniature pressure transducers. The effect of clocking on the unsteady pressure fluctuation at MS on the rotor blades is discussed for different operating points. Based on the unsteady profile pressures, the blade pressure forces were calculated. The peak-to-peak amplitudes of the unsteady blade pressure forces are presented and analysed for different clocking positions at both the design point and the operating point near the stability limit of the compressor.
357

Design and Manufacturing of IPM Synchronous Motor for Field Weakening Operation

Finnman, Jonas, Eketorp, Erik January 2013 (has links)
Rotor designs for permanent magnet synchronous machines suitable for field weakening operation have been evaluated for use with an existing drive system. The designs have been simulated with the FEM-based software Finite Element Method Magnetics (FEMM). Based on the results two different internal magnet rotors have been constructed and tested. Both designs significantly improved the speed range while maintaining or improving magnet utilisation. The implementation of field weakening algorithms in drive electronics is complex and need thorough optimisation for stable operation. Internal permanent magnet rotors are a good alternative to surface mounted designs and enables a wider speed range through improved field weakening capabilities.
358

An integrated brake disc and electric drive for vehicle propulsion : A FEASIBILITY STUDY

Linder, Johan January 2016 (has links)
In this thesis, the feasibility to integrate an brake disc and electric machine is investigated. In wheel motors (IWMs) have several advantages, such as saving space in the vehicle, individual and direct control at the wheels and the absence of a mechanical transmission. However, today’s IWMs are heavy and, thus, negatively affect the driving performance of the vehicle due to the increase of the unsprung mass. By integrating an already existing part in the wheel, this increase of the unsprung mass can be minimized. The brake disc manages high temperatures, a significant wear in rough environ-ment, which puts high demands on the rotor. The second part of the machine, the stator, will be significantly affected by the high temperatures of the rotor. The temperatures of the stator are transferred by convection, conduction and radiation from the rotor or brake disc. Liquid cooling of the stator back is analyzed as a potential solution for handling the high temperatures. In order to analyze the feasibility of the concept, thermal, electric and mechanical modelling has been used. The evaluation whether it is possible or not to integrate the brake disc has been with regard to the results of weight, cost, thermal tolerance and electric performance. / I detta arbete undersöks möjligheten att integrera en bromsskiva med elmaskin. Hjul-motorer har flera fördelar, bland annat sparas utrymme i själva bilen, individuell kontroll samt drivning av hjulen utan mekaniska transmissioner. Men hjulmotorer som kan användas idag väger oftast så pass mycket att den odämpade massan ökar kritiskt och köregenskaper av fordonet då blir lidande. Genom att integrera en befintlig del i hjulet kan ¨okningen av odämpade massan minskas. Att använda bromsskivan som rotor, kräver att denna tål temperaturer ¨over 500◦C samt påfrestningar och slitage som en vanlig mekanisk friktionsbroms måste uthärda. Den andra delen av maskinen, statorn kommer även denna att påverkas av de höga temperaturerna av bromsskivan som kommer ledas via konvektion, konduktion och strålning. Möjligheten att kyla statorn med vätska och om detta är tillräckligt undersöks. För att analyserna genomförbarheten av projektet har termiska, elektriska och mekaniska modeller använts. Resultaten har analyserats där maskinens vikt, kostnad, termisk tålighet och elektrisk prestanda har legat till grund för bedömningen om lösningen; att integrera en broms-skiva med elmaskin är rimlig eller ej.
359

Simulating Dynamical Behaviour of Wind Power Structures

Ahlström, Anders January 2002 (has links)
The workin this thesis deals with the development of anaeroelastic simulation tool for horizontal axis wind turbineapplications. Horizontal axiswind turbines can experience significanttime varying aerodynamic loads, potentially causing adverseeffects on structures, mechanical components, and powerproduction. The need of computational and experimentalprocedures for investigating aeroelastic stability and dynamicresponse have increased as wind turbines become lighter andmore flexible. A finite element model for simulation of the dynamicresponse of horizontal axis wind turbines has been developed.The simulations are performed using the commercial finiteelement software SOLVIA, which is a program developed forgeneral analyses, linear as well as non-linear, static as wellas dynamic. The aerodynamic model, used to transform the windflow field to loads on the blades, is a Blade- Element/Momentummodel. The aerodynamic code is developed by FFA (TheAeronautical Research Institute of Sweden) and is astate-of-the-art code incorporating a number of extensions tothe Blade-Element/Momentum formulation. SOSIS-W, developed byTeknikgruppen AB was used to develop wind time series formodelling different wind conditions. The model is rather general, and different configurations ofthe structural model and various type of wind conditions couldeasily be simulated. The model is primarily intended for use asa research tool when influences of specific dynamic effects areinvestigated. Simulation results for the three-bladed wind turbine Danwin180 kW are presented as a verification example. <b>Keywords:</b>aeroelastic modelling, rotor aerodynamics,structural dynamics, wind turbine, AERFORCE, SOSIS-W,SOLVIA / NR 20140805
360

Non-Linear Control of a Tilt-Rotor Quadcopter using Sliding Mode Technique

Sridhar, Siddharth 16 June 2020 (has links)
No description available.

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