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Modeling two-phase bubble flow in microfluidics
Stehlík, Martin ; Kozák, Jiří (referee) ; Rudolf, Pavel (advisor)
The goal of submitted thesis is to perform a computer simulation of bubble creation in T-channel. In the first section of the paper, the theoretical applications of microfluidic bubble, micromachines and droplet formation are described. In the second part of the text, author uses cross flowing method for simulation od bubble creation. Furthermore, several settings in computer simulation software Fluent are mentioned. In addition, the influence of velocity at the T-channel inlet on surface tension and on bubble length is presented.
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Verification of thermal-insulation properties of the foil materials
Šot, Petr ; TROJAN,, Karel (referee) ; Šťastník, Stanislav (advisor)
The master´s thesis deals with verification of thermal insulating property of thermoreflection foil insulations. The teoretical part of thesis focuses on the energy demand of buildings, the problems of heat transfer material, terms required for study of thermoreflection thermal insulation and experimental methods for determination of thermal insulating properties of insulators. In the next part the chapter is accompanied by an overview of the most common insulation materials which used in construction. The last part of teoretical part is devoted to the description of thermoreflect formation and analysis of the spread of thermal insulating layers of thermoreflection thermal insulation. The first part of thesis is devoted to the use of thermoreflection therm insulation in buildings. The second part of thesis is devoted to the design, assembly and calibration of the measuring device that uses a method of protected warm chamber. It is declared as a binding method of detection of the heat transfer performance of thermoreflection thermal insulation. The developed measuring device allows detection of endpoints in some direction of propagation of heat. Measurment of heat transfer coefficient devoted the third part of practical part. This part contains a description of the samples used for the measurement of the heat transfer coefficient. In the fourth chapter of the practical part are presented the results of the heat transfer coefficient measurments on selected samples of thermoreflection foil insulation. It is shown the characteristic of heat transfer coefficient of individual samples, the dependence of the heat transfer coefficient on the position of the sample in the measuring device and the recommendation of an appropriate use of sample in the works for the climatic conditions of the Czech republic. The work concludes the chapter of comparing and evaluating of all samples with practical recommendations.
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Laboratory Model of the Vortex Speed Indicator
Kazda, Ondřej ; Kolka, Zdeněk (referee) ; Biolková, Viera (advisor)
This work is concerned with posibility of measuring a wind flow by Von Karman vortex sheed structure. The bluff body is situated in the way of air flow propagation and consequentally vortexes will be appeared. Important part of speedmeter design is measurment chamber must allow to vortex sheed propagation. The transient and the reciever are situated vertically to propagation of flow.The Ultrasonic carrier is transmitted and modulated by freqency of vortex sheeding in measurment chamber.Demodulator uses PLL to “focusing“ detection of the ultrasonic beam. This can be indicated like lock and unlock phase loop. From known value of sheed frequency can be directly calculated speed of flow.
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Research study of „Tilt pad bearings“ (computational and experimental modelling)
Havlásek, Michal ; Chlud, Michal (referee) ; Malenovský, Eduard (advisor)
The bachelor’s thesis is focused on the computational and experimental modelling of the tilting pad bearings. The computational and experimental modelling is based on solving the lubrication theory provided by English professor Osborn Reynolds, published in 1886. The main part of the thesis is the description of the most widely used computational models, especially TEHD analysis, and the description of the only two experimental devices for the testing of the tilting pad bearings. The thesis is supplemented with the prediction of the development of the computational modelling in the near future.
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Comparison of the real and idealised human airways model
Roupec, Michal ; Elcner, Jakub (referee) ; Forman, Matěj (advisor)
The purpose of this thesis is to find basic parametres of idealized geometrical lung models – Weibel’s and Horsfield’s and to measure length and diameters of each pipe from trachea to 4th generation of bifurcation. Using 3D model (scanned casting of bronchial tree of man) measure matching diameters and lengths of airways and compare them with lengths and diameters of both models. Define bifurcation angles and total geometry of real lungs. Calculate Reynolds number knowing velocity in some of the airways for real lungs and both models and compare them.
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Pressure losses in heating systems
Švanda, Martin ; Horká, Lucie (referee) ; Počinková, Marcela (advisor)
This diploma thesis deals with pressure losses in heating systems. The diploma thesis is divided into three sections. The first part is theoretical and deals with the occurrence of pressure losses. It discusses the properties of the fluid that affect pressure losses. It also deals with hydrodynamic phenomena, flow distribution, pressure loss distribution and its calculations. The aim of the second part, which is practical, was to create a heating project for a selected object. The object is a two-floor kindergarten building located in Velké Němčice. For this project, two heating variants were created. For the first variant, radiators and heating benches were designed and for the second variant, underfloor heating was installed in the building. The goal was to use a source which will gain heat mainly from renewable sources, so the air / water heat pump was chosen as the source of heat production. The project ends with a technical report. The third part of the thesis is dedicated to an experiment which purpose was to find out how the pressure losses of the connecting pieces are reacting to the change with the change of the heating water conditions (flow, temperature). Alongside, two pipes were created which differed in the type of connecting pieces so it allowed to compare how their pressure losses differ. Both pipes were connected by radial pressing, but the fittings differed in the quality of the brass, and therefore in the construction. Also, part of the experimental section of the diploma thesis is a description of the course of radial pressing of fittings from the Herz company.
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Methods for Kármán vortices suppression
Kukrle, Daniel ; Urban, Ondřej (referee) ; Rudolf, Pavel (advisor)
This bachelory thesis is considering a Kármán vorticies and their suppresion. The theoretical part describes principle of phenomenon origin and concepts connected with this topic. Following chapter deals with Kármán vortex street occurrence and danger. In the end of the first part there is an overview of phenomenon suppresion methods. Experiment applies selected suppresoin methods and proves their effectivness.
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Discharge coefficient of slit weirs
Havran, David ; Žoužela, Michal (referee) ; Zachoval, Zbyněk (advisor)
This work deals with experimental research, with outcomes of design and recommendation for determination of the discharge coefficient of the slit weir. At the same time states the possible effects on capacity. Then comparing the data with already existing ones. The thesis provides an overview and insight into the meaning of slit weirs as well. The goal is to recommend the determination of the discharge coefficient.
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