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Flow visualization methods
Ďurdina, Lukáš ; Jedelský, Jan (referee) ; Lízal, František (advisor)
ĎURDINA, L. Flow visualization methods. Brno: Brno University of Technology, Faculty of Mechanical Engineering, 2010. 45 p. Thesis supervisor Ing. František Lízal. This thesis deals with fluid flow visualization methods with respect to their practical application possibilities. Chronological description of the historically valuable visualization experiments emphasises the role of visualization in the experimental fluid mechanics. A brief characteristic of the flow field contains mathematical description of the objects, which can be visualized. Visualization methods are divided into experimental and computer aided methods. Individual methods are ordered subsequently beginning with those with lowest requirements for equipment to the more sophisticated methods. Various techniques, which provide qualitative and quantitative description of the tested gas or liquid flow, are described. The overview for the choice of methods for various applications sums up the important facts from previous chapters. Description of a simple helium bubble flow visualization experiment realized in a lab can be found at the end of the thesis.
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Modern flow visualization techniques
Pištěcká, Kateřina ; Koutník, Tomáš (referee) ; Popela, Robert (advisor)
The subject of this bachelor thesis is an overview of the flow visualization methods applied in the wind tunnels and fly tests. An overview of flow visualization methods is presented in the first part of the work. The particular methods are presented and evaluated with respect of its complexity, requirements on the instrumentation and expanses. The pros and cons are mentioned for each method finally. The second part of the work deals with selection of the flow visualization method suitable for application in the wind tunnel of the Aeronautical department of the VUT Brno.
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Realization of Educational Problem on Experimental Apparatus for Measurement of Gear Efficiency
Runštuk, Jiří ; Mazůrek, Ivan (referee) ; Klapka, Milan (advisor)
This diploma thesis is focused on the implementation of the educational role of the experimental station for measuring the effectiveness of gears. The proposed laboratory task "Experimental measurement of the effectiveness of gears" is intended to familiarize students with the basic principles of gears and especially highlight the issue of the effectiveness of gears. In this presented thesis, it is also suggested the possibility of expanding the educational use of the experimental station. This extension deals with vibration diagnostics of frequencies of gears.
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Problems in machining of titanium alloys
Drábek, Tomáš ; Slaný, Martin (referee) ; Sedlák, Josef (advisor)
The theoretical part of the thesis contains a brief overview of some experimental methods that are used in machining technologies. The experimental part at first elaborates on the analysis of two titanium alloys. The actual experiment, which consists of milling of the two aforementioned materials with the use of several tools and holders, is then described. It was conducted in collaboration with the company Frentech Aerospace s.r.o. When milling, forces were measured with piezoelectric dynamometer. Further, the analysis of acquired data that is followed with discussion about its main findings, is provided. The conclusion of the thesis deals with the found facts corresponding with the information obtained by analysis of materials. The main results arise out of the comparison of used combinations of tools and holders for milling of material Ti-Al6-V4, observation of impact of particular factors on measured force, or out of different values of measured forces when milling two given materials.
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Analysis of cutting tool wear while turning construction steel
Kudela, Jan ; Kouřil, Karel (referee) ; Sedlák, Josef (advisor)
The goal of the thesis is wear analysis of cutting inserts used for machining 42CrMo4 steel. Theoretical part of the thesis contains comparison of turning and milling machining processes, machining methods for ball screws made of 42CrMo4 and description of experimental methods of tool wear analysis. Experimental part of thesis contains methodology of cutting inserts wear measurement for chosen machining method. The following testing is focused on cutting insert wear as well as workpiece surface analysis. Thesis is finished with processing of measured data and overall evaluation of achieved results.
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Cutting Tests of Insert for Turning Structural Hardened Steel
Šolc, Michal ; Pokorný, Zdeněk (referee) ; Sedlák, Josef (advisor)
The thesis deals with the wear of replaceable inserts during the turning of structural hardened steel. The theoretical part describes a brief characteristic of turning technology, force loading on tools and tools used in turning. Moreover, it contains an analysis of the chemical composition of the machined material, its microstructure and microhardness. Machines and equipment used for the experiment and their specifications. The experimental part of the thesis describes the method of measuring and evaluating of tool wear, followed by the cutting tests themselves, documenting of the result and their evaluation. The conclusion of the thesis is the processing of measured data, the evaluation of achieved results and the proposal of further steps to improve the process.
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Experimentální měření fyzikálních parametrů půdy na vybraném pozemku
BALOUN, Tomáš
The bachelor thesis deals with soil as such, its properties with a focus on physical soil parameters and evaluation of experimentally obtained measurement results. Samples were taken from the farm's family farm. The scope of the work was processing of samples and selection of suitable methods to obtain such soil parameters, which can be subsequently used as input data for computer simulations focused on soil compaction after crossings of agricultural machinery.
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Study of physical properties of nanostructures using magneto-optical techniques
Beran, Lukáš ; Veis, Martin (advisor) ; Mistrík, Jan (referee)
Magneto-optical spectroscopy methods are used to study magnetic pro- perties of materials down to nanometer dimensions due to its high sensiti- vity and non-contact nature. This requires sophisticated experimental setup, advanced technical equipment and precise optical components arrangement. This thesis describes the basic physical principles of magneto-optical Kerr spectroscopy. On the basis of these principles is designed and developed a new, much simpler experimental setup with crossed polarizers. This arran- gement has the same order of sensitivity and accuracy of measurement as commonly used modulation techniques to which it is compared in this work. Finally, this arrangement is applied to the study magneto-optical properties of selected magnetic structures and these properties are discussed. 1
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Cutting Tests of Insert for Turning Structural Hardened Steel
Šolc, Michal ; Pokorný, Zdeněk (referee) ; Sedlák, Josef (advisor)
The thesis deals with the wear of replaceable inserts during the turning of structural hardened steel. The theoretical part describes a brief characteristic of turning technology, force loading on tools and tools used in turning. Moreover, it contains an analysis of the chemical composition of the machined material, its microstructure and microhardness. Machines and equipment used for the experiment and their specifications. The experimental part of the thesis describes the method of measuring and evaluating of tool wear, followed by the cutting tests themselves, documenting of the result and their evaluation. The conclusion of the thesis is the processing of measured data, the evaluation of achieved results and the proposal of further steps to improve the process.
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Experimental Methods to Study Aerosol Nanoparticles.
Ždímal, Vladimír ; Schwarz, Jaroslav ; Ondráčková, Lucie ; Ondráček, Jakub
During the last few decades, the experimental possibilities of studying aerosol particles have grown enormously. Not only is it possible to determine the particle size distribution in different metrics, not only can the chemical composition of the size-resolved aerosol be determined, but methods have been developed over the last two decades that allow all of these tasks to be handled in real time. These methods stem from several basic physical principles: molecular diffusion based on Brownian motion, electrostatic separation of particles with predictable charge, condensational growth of particles, gravitational settling, acceleration of particles in nozzles, inertial impaction, and light scattering on particles.\nHowever, if we are specifically interested in separating particles smaller than 100 nanometers in diameter, the choice of experimental methods would be substantially reduced. In fact, we have only four physical principles that can be utilized in this size range with reasonable degree of uncertainty: Brownian motion, electrostatics, impaction and condensation. For the determination of the chemical composition in a given size range, the most commonly used is a combination of physical / chemical ionization with mass detection, however, the range of quantifiable substances is greatly limited.\nRecently, exposure monitoring of workers in the production of engineered nanoparticles has become increasingly important. Here, the task is further complicated by the fact that it is necessary to sample directly from the vicinity of the worker's mouth to determine personal exposure. As far as the collection of nanoparticles in the respiratory zone is concerned, there is not yet a great choice of options, and experimental methods are still being developed and tested. A promising alternative is a stationary measurement, where state-of-the-art aerosol spectrometers are located close to the working space of the personnel, so that the actual exposure of the worker can be estimated. In this case, however, it is necessary to calibrate the on-line instruments by comparison with simultaneous personal collection.\n
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