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Design of a heat exchangers for cooling process gas
Janoušek, Petr ; Baláš, Marek (referee) ; Toman, Filip (advisor)
Heat exchangers are one of the most used devices in the energy industry. This thesis deals with the overall design of heat exchangers according to the required parameters. Its aim is to perform thermal and hydraulic calculation of two different heat exchangers designed for process gas cooling and compare their resulting design. Specifically, the thesis designs shell and tube heat exchangers, where the first one is an exchanger with straight tube and the second one is an exchanger with U-tubes. The first and second chapters are theoretical sections dealing first with the general issue of heat exchangers and then specifically with shell and tube heat exchangers. The complete design of the straight tube heat exchanger is carried out in chapter three, where its modelled form is also presented. The following chapter deals with the design of the second U-tube exchanger. The final chapter copes with the evaluation and comparison of both types.
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Icing on radiator used for heat pump for EV vehicles
Ostroukhov, Andrei ; Růžička, Marek (referee) ; Bazala, Jiří (advisor)
Tato práce je zaměřena na vliv kondenzace na přenos tepla chladičem elektromobilů. Teoretická část popisuje princip systému tepelného čerpadla a obsahuje také popis přenosu tepla v radiátoru a kondenzace na jeho povrchu. Práce popisuje řešení pro snížení množství kondenzátu, byly demonstrovány různé metody. Byl také popsán proces vzniku námrazy, tvorby ledu na povrchu výměníku tepla a také byli popsané mechanická poškození způsobené námrazou. V praktické části bude použit simulační software pro porovnání množství kondenzátu, který se objeví na povrchu výměníku tepla při použití některých níže popsaných metod. Simulace také určí závislost tepelného toku na množství kondenzátu.
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Design calculation of heat exchanger for cooling of aggressive substances
Kůra, Tomáš ; Jegla, Zdeněk (referee) ; Kilkovský, Bohuslav (advisor)
This thesis focuses on the design of a coaxial tube in tube heat exchanger. First, the existing methods of cooling of aggressive substances are presented. Subsequently, the compatibility of the heat exchanger materials with substances used in the semiconductor industry is addressed and the PFA polymer is presented in detail as a suitable material. The paper further explains heat transfer, both in general and specifically in heat exchangers. Not only the relationships commonly used in heat exchanger design are presented, but also equations for coaxial heat exchangers. The individual empirical equations are compared with measured data, and on this basis, the most appropriate relations are chosen to describe the processes in the exchanger under investigation. Then, the work describes the operation of the developed program in VBA, which includes thermal and hydraulic calculations and strength control.
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Design of a cryogenic exchanger for process gas liquefaction
Wittek, David ; Kudela, Libor (referee) ; Toman, Filip (advisor)
The energy density of liquid natural gas is more than five hundred times higher than in state of gas. A key component for its preparation is the heat exchanger, where the liquefaction takes place. The aim of this work is design of a condenser. Its implementation is like Giaque-Hampson type exchanger with a bundle of helical wound tubes. Technical solution for the device is proposend and various configuration of heat-carryig media placement are compared. Concepts with condensation inside the tubes and in the shell are studied. In addition to ensuring safe operation within the design conditions, there are fucused on minimizing the size of the equipment and the associated production costs.
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Modern Cooling Concepts of Electrical Machines
Lukášek, Jan ; Cipín, Radoslav (referee) ; Toman, Marek (advisor)
The thesis focuses on the research of modern concepts of cooling of electrical machines. The first part of the thesis deals with the origin and calculation of losses causing heating of electrical machines. The second part describes the mechanisms of heat transfer and basic relations of fluid mechanics. The third part describes the basic principles of cooling of electrical machines. The final part of the thesis describes modern concepts and innovations in cooling systems for electrical machines described in the third part and separate modern innovations.
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Influence of Material Properties and Mixing Dynamics on Heat Transport in Granular Materials
Kokavcová, Anna
This study evaluates the effect of rotational speed on heat transfer and analyzes particle motion at different stirrer rotational frequencies to understand how primary and secondary flows affect heat transfer efficiency. It also examines the effect of Young’s modulus on heat transfer at different agitator\noperating speeds. Key simulation parameters and their influence 33 on heat transfer efficiency are detailed to improve the reproducibility and applicability of the results.
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Počítačové modelování tepelného namáhání skleněné tabule při gravírování laserem
ZOUBEK, Tomáš
Computer modelling is often used to understand the nature or behaviour of physical phenomena. In this work, a three-dimensional computer model was created from a 25x30x4 mm (width x height x thickness) glass plate on which twenty dots with a radius of 371.54 ?m were burned using a laser engraving process. The distance between the dots was 1.25 mm. A computer simulation of the thermal stress of the laser engraving process was carried out on this model. The input parameters used were the laser travel time between points (0,5 s^(-1)), the duration of the laser discharge (0,5 s^(-1)), the laser power (30 W), the laser intensity and the laser density over a given area (given by equation 11), the heat flux coefficient of the glass sheet (5,7 Wm^(-2)K^(-1)) and the function controlling the firing of the laser beam at specific points and times (equations 5.4 and 5.5). The simulation was carried out for two variants that differed in the order of the fired points. For the first variant, the points were fired chronologically from left to right in rows, whereas for the second variant the points were fired in the order 1, 3, 5, 11, 13, 15, 7, 9, 17, 19, 2, 4, 12, 14, 6, 8, 10, 16 and 20. The second variant proved to be more optimal for the geometry and material studied. It resulted in less thermal stress, as lower temperatures were achieved with a defined laser beam, and at the same time there was a greater time delay between processes stressing the same locations.
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Optimization of Thermally Activated Building Structures
Oravec, Jakub ; Kalousek, Miloš (referee) ; Čekon, Miroslav (referee) ; Šikula, Ondřej (advisor)
The thesis deals with the modelling, analysis and optimization of thermally activated foundation piles using the in-house developed numerical software Epile. A sensitivity analysis of short energy piles was performed and a deep regression neural model was developed to predict the energy gain of the pile. A Bayesian optimization method was implemented to find the optimal parameters of the energy piles in order to maximize the financial and energy gain.
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Design of a nitrogen Dewar vessel for electron microscopes
Brauner, Tomáš ; Voňka,, Jakub (referee) ; Urban, Pavel (advisor)
Observation of biological samples in electron microscopes in a state closest to the native state requires reaching cryogenic temperatures, most often with the use of liquid nitrogen (LN2). For this purpose a Dewar vessel with cooled copper thumb for cooling the sample holder and anticontamination shield inside the vacuum chamber of the scanning electron microscope (SEM) and focused ion beam (FIB) source was designed. Characteristics of the designed LN2 Dewar vessel were validated by measuring executed on the real functional sample. The reached temperature at the tip of the thumb under estimated heat load 2 W was 90,8 K. Corresponding refilling interval of LN2 is about 11 h. Experimentally measured data correlate with theoretically calculated characteristics. The designed Dewar vessel with a cooled thumb fulfills the required properties specified in the thesis assignment with a margin.
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Experimental equipment for testing of heat pipes efeciency
Vostřel, Vít ; Lošák, Petr (referee) ; Vlach, Radek (advisor)
This bachelor thesis deals with construction of a measuring apparatus for measuring efficiency of heat pipes. The thesis first discusses heat pipes and all components of the measuring apparatus in theoretical way and than it describes construction of the real model and all needed calculations. The apparatus contains a movable arm to which the measured heat pipes are attached. The Arm is able to move form 0° to 90°. The apparatus construction procedure is also described here. The whole apparatus is controlled from the computer using Excel, macros created in Excel and Data Streamer tool.
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