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Measurements of the stress in the turbine spiral casing using the strain gauges
Dokoupil, Pavel ; Pochylý, František (referee) ; Habán, Vladimír (advisor)
The Master‘s thesis is focused on measuring of the stress in the spiral case of water turbine using the strain gauges measurement. It contains the theoretical and the practical part. The theoretical part includes a description of theoretical background (basic mechanics, measurement and evaluation, strain gauges, pressure measurement, uncertainty of measurement). One of the chapters describes Water Power Plant Lipno nad Vltavou (history of power plant, issues and the history of measurement). The practical part contains a theoretical calculation of measurement uncertainty and measuring of stress on spiral case Francis turbine at Water Power Plant Lipno I (Unit TG2). Measurement was made before and after overhaul. There are described technical data of spiral cases, description of measurement, results of measuring of strain and stress including comparison with the pressure in spiral case and calculation of uncertainties of measurement.
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An innovation of production technology of pressure reservoirs
Caha, Lukáš ; Humár, Anton (referee) ; Píška, Miroslav (advisor)
The target of Master Thesis with theme „The innovation of production technologie of pressure reservoir“, is a description of manufacturing technologie currently in use and design a new technologie. Part of new development of technologie is a selection of suitable spectrum of rails (pressure reservoir), design invention of appropriate machine loading system and clamping fixture placed into machine. Also the comparison of technologckl and economical parameters of proposed designed technologies and technologie currently in use - the final evaluation included.
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Interaction of ultrashort laser pulses with semiconductor nanostructures
Preclíková, Jana ; Malý, Petr (advisor) ; Potůček, Zdeněk (referee) ; Oswald, Jiří (referee)
The thesis is devoted to the optical spectroscopy (photoluminescence, transmission, ultrafast photoluminescence) of nanocrystalline diamond films and silver nanoparticles in titanium dioxide matrix. We studied the influence of the laser irradiation on optical properties of both materials under various conditions. Nanocrystalline diamond exhibits strong subpicosecond and picosecond photoluminescence parameters of which (intensity and decay rate) change with the laser irradiation and ambient air pressure. The effects are accompanied by a change in optical thicknesses of the nanocrystalline diamond films. We assigned the phenomena to light induced adsorption processes which influence the subgap states originating from surface and grainboundaries atoms. We implemented and optimized the preparation technique of the nanocomposite Ag-TiO2films exhibiting the multicolour photochromic effect. The analysis of the initial stages of the photochromic transformation revealed that during the laser irradiation the plasmon frequency of the resonating silver nanoparticles was blue shifted. The photoluminescence spectroscopy confirmed an increase in number of the Ag+ ions during the photochromic transformation. The photoluminescnece of the nanocrystalline TiO2 is due to the two types of radiative transitions: the...
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Prediction of slow crack growth in polymer pressure pipes
Luky, Robin ; Knésl, Zdeněk (referee) ; Hutař, Pavel (advisor)
A new methodology of polymer pipe lifetime estimation taking into account residual stresses is described in this thesis. Engineering equations derived based on numerical simulations of a hydrostatic pressure test are proposed. Residual lifetime calculations were performed for different loading conditions using experimental data of a creep crack propagation in studied material and stress distribution in the pipe wall. The effects which significantly influence lifetime estimation were quantified with special focus on residual stresses.
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Stress-strain analysis of artificial vascular grafts
Chomič, Dimitrij ; Návrat, Tomáš (referee) ; Burša, Jiří (advisor)
This thesis deals with the computational solution of stress-strain states in the vicinity of the connection (anastomosis) between artery and vascular replacement. An „end to end“ anastomosis loaded by inner light increased constant systolic blood pressure is modeled in the thesis. The connection is modeled by different variants of the bonded contact and attachment of a surgical stitch. To solve the stress-strain state constitutive models were used in the finite element software package ANSYS 13.0. Material properties of arteries and vascular grafts were taken from measurements made at the Institute of solid mechanics, mechatronics and biomechanics.
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Calculation of the thermal diagram high load steam turbine with steam reheating
Cerman, Marek ; Lázničková, Ilona (referee) ; Raček, Jiří (advisor)
The major topic of this bachelor’s thesis is calculation of thermal diagram with condensing steam turbine. In the first section the project is focused on the theory of steam cycles. In nine separate chapters the reader is briefly introduced to the principle of steam turbine as well as to some common type of steam turbines, basic diagrams of steam cycles and their illustrations in T-s diagram and Mollier h-s diagram. The attention is then individually focused on the process of energy change, how is the steam energy transformed into a mechanical energy, the inference of turbine output power, the assesment of actual efficiency of steam diagram systems and on the facilities that allow for an increase of the efficiency in practice. In the second section of the project, the calculation of thermal diagram of free-cylinder turbine with steam reheating is introduced as a follow-through to the theoretical basics. The rated output of the turbo-set is 100 MW. The thermal cycle is defined by the main steam parameters, the reheat parameters and the emission pressure. Setting component is basic thermal diagram which foremost introduces the connections of system of regenerative heaters from the point of utilisation of the heating steams condensates. First chapter of the second section targets the general method of solution, which in connectedness consists of the concept of steam expansion in the turbine, the concept of heating feed water in regenerative heaters, the assignment of the mass steam flows in the cycle and the assignment of energy index figures. The method analysis is, even in the scope of determining basic parameters detailed. In the second chapter, the general method is subsequently applied to a numeral calculation of the given diagram. Here, the method that exploits computer software is demonstrated. It will assert itself with the instancy, the calculation may be proceeded with, compared to common use of water and steam tables and to the accuracy to which the quantity values of working substance are marked during various thermodynamic phases. All of the significant figures defining the designated thermal cycle are calculated. In the conclusion the values are summarized in a table and picture overview and evaluated.
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Investigation causes of the premature capacity loss in accumulator for hybrid electric vehicles
Vystrčil, Marek ; Bilko, Radek (referee) ; Bača, Petr (advisor)
This thesis describes the results of two successive experiments. The first was focused on the influence of impurities in the active mass of negative electrode in PSoC (Partial State of Charge) mode, which simulates the conditions occurring in HEV (hybrid electric vehicle). In the second experiment, cells with the same additives were exposed to optimum downforce 4N/cm2, by which we wanted to prove the influence of pressure on life of VRLA (Valve Regulated Lead Acid) cells working in operating HEV conditions.
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Experiment E3/2 - Vliv teploty na boční tlak sypkého tělesa
Valach, Jaroslav ; Koudelka, Petr
The first part of long-term experiment E3 with passive pressure has been started in the second half of 2001 and carried out during 2002. The partial experiment has been marked E3/2 according to the second type of the wall movement (rotation about the top). The paper presents the analysis of temperature changes of the stand structure at the results of the experiment E3/2.
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