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Study efficiency of modern thermal insulation for buildings
Šot, Petr ; auditor, Karel Trojan, Brno, energetický (referee) ; Šťastník, Stanislav (advisor)
The bachelor´s thesis deals with the problem of thermoreflect insulation. The small part of thesis focuses on the energy demand of buildings and its problems. Then the greater extent is analysed problems by heat transfer of material. It includes effects arising from the individual methods of heat transfer and defines the level of expression of individual methods of heat transfer in materials. The thesis presents an overview of experimental methods for determining thermal insulating properties of insulators. Then there is shown a selection of the most widespread insulation materials used in today´s construction. It includes the division of insulators in terms of used materials and subsequent classification of the most used materials in these groups. Another part of thesis deals with the thermoreflect isolation. There are mentioned the necessary concepts for the study of thermoreflect thermal insulation, which include the emissivity surface, the coefficient of mutual radiation and translucency of the material. Then there is described the method heat transfer of thermoreflect isolation. On the next there are presented experimental methods of determining thermal insulating properties thermoreflect thermal-insulating material. The thesis also includes a practical part, which contains the measurement results on a small range of samples taken termoreflection insulators. In the end there is mentioned a brief realization of thermoreflection thermal insulation materials in buildings.
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Improving friction of lubricated contacts by modifying thermal conductivity
Šnevajs, Matěj ; Hartl, Martin (referee) ; Šperka, Petr (advisor)
This thesis deals with an experimental study regarding the effects of the thermal conductivity of contact bodies on the friction, lubricant film thickness and temperature distribution in EHL contact. The thesis focuses on the configuration of the ball on disc contact. The contact body materials are characterized by a wide range of thermal properties. New contact pairs are proposed and used in the study in order to make the contact bodies’ thermal properties dependent on the behaviour of EHL contact. The colorimetric interferometry method is used to measure the lubricant film thickness and the infrared thermography method is used to observe the temperature distribution in EHL contact. The author presents the assumed mechanism of heat transfer within EHL contact on the basis of different heat transfer mechanisms. The same conditions – such as the Hertz pressure, mean entrainment speed, sliding speed and ambient temperature – are induced for all the contact pair combinations. That is why the differences in the results are attributed to the different thermal phenomena in the contact, caused by the thermal properties of the contact bodies. In the case of contact bodies with a reduced heat dissipation capability, a reduction of the friction coefficient of up to 50 % is observed, which is attributed to an increase in the lubricant temperature, resulting in a decrease in its viscosity. This is confirmed by the infrared thermography method, whereby a significantly higher lubricant temperature is observed in the case of a combination of contact materials with a lower heat dissipation capability.
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Study of heat transport throw bulk materials with electric conductive aditive
Vacula, Jan ; Menčík, Přemysl (referee) ; Zmeškal, Oldřich (advisor)
Bachelor thesis is focused on the study of heat transport in bulk materials made from PLA (polylactic acid) filaments by 3D printing. For subsequent applications it is important to know the electrical, dielectric and thermal parameters of materials with different dyes, pigments and electrically conductive additives. The aim of this work is mainly to study the thermal properties of the series and the influence of additives on these properties. The main focus is to study the thermal properties of the samples. In the theoretical part, different 3D printing methods are mentioned, the methods of measuring the thermal properties, and finally the properties of the lactic acid polymer are described. The experimental part is devoted to the description of the process of 3D printing samples for measurements and then the method of measuring the thermal properties of the printed samples is described. For samples with electrically conductive admixtures, the thermal conductivity was found to be in the range of (0,217–0,292) W/m/K and the specific heat capacity was found to be (382,2–1 007,2) J/kg/K. The electrically conductive materials (PLA with metallic admixtures) were found to have a very good thermal conductivity and a smaller specific heat capacity, while the materials with admixtures of dyes and pigments showed a smaller thermal conductivity and a larger specific heat capacity.
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High temperature coatings for gas turbine blades
Chýlek, Radomír ; Brázdil, Marian (referee) ; Šnajdárek, Ladislav (advisor)
The purpose of this bachelor thesis is the overview of technology of high temperature coatings for gas turbine blades. The familiarization with properties of individual coatings, their capabilities to increase the blades durability and their resistance to damage and temperature influences are emphasized in this work. The potential of significant increase of gas turbines efficiency using different types of coating and cooling of the blades was evaluated in this thesis. Additionally the individual coating techniques are described and compared. Last but not least, this thesis contains closer description of the state-of-the-art thermal barrier coatings including the characteristics required for the following computing part. The computing part deals with calculation of heat transfer through the blade. The conclusion is dedicated to the future use of the coatings from the author's perspective.
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Development of a new self-supporting insulation system with respect to dynamic stress
Machala, David ; Frajt, Daniel (referee) ; Drochytka, Rostislav (advisor)
This diploma thesis deals with suggestion of self-supporting insulating system that can be used for objects which insulating is more or less complicated. In this thesis are theoretically processed information about insulation systems while focus is on their structure, composition and principle of operation. Further, there is theoretically designed self-supporting insulating system which is practically built after theoretically composed testing for finding its basic properties. The most appropriate process of realization is formulated at the end after evaluation of the individual tests.
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Thermal Mass Flowmeter
Mlčoch, Albert ; Kunz, Jan (referee) ; Beneš, Petr (advisor)
The thesis deals with the design of a mathematical model and practical implementation of a flowmeter based on the thermal principle. The range of the proposed flowmeter is from units of kilograms per hour to lower hundreds of kilograms per hour. The design of the flowmeter is non-invasive to the flow channel, the heating element is located outside the pipe. In this paper, the flowmeter parameters are identified and a temperature regulator is proposed. Measurements are made on a test bench. The results of the measurements are discussed. Modifications to the existing hardware are suggested.
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Analysis of boundary conditions of ground heat exchangers
Floreková, Skarleta ; Horák, Petr (referee) ; Hirš, Jiří (advisor)
Diplomová práca,, ,,Analysis of boundary conditions of ground heat exchangers,, je primárne zameraná na analýzu okrajových podmienok a hlavných faktorov vplývajúcich na spoľahlivý návrh a prestup tepla plošného zemného výmenníka v oblasti geotermálnych aktivít na kúpeľnom ostrove v Piešťanoch. Posúdenie možných vplyvov na životné prostredie, ako je napríklad vznik tepelných zmien v dôsledku extrakcie tepla vrátane zamŕzania pôdy v okolí potrubia a potenciálneho znečistenia podzemných vôd je taktiež rozoberané. Súčasťou tejto záverečnej práce boli spracované tri numerické analýzy metódou konečných prvkov pomocou softvéru COMSOL Multiphysics 5.6., ktoré sa môžu vyskytnúť v tejto konkrétnej oblasti. Prvá numerická analýza je podrobená štúdii dynamických procesov plošného zemného výmenníka tepla a zeminy nasýtenou vodou pri konštantnej teplotnej okrajovej podmienke pôdy. Dynamický proces zemného výmenníka tepla a nasýteného podložia pri nestálej teplotnej okrajovej podmienke je skúmaný v druhej numerickej analýze. Posledná analýza je vyhotovená na posúdenie prevádzky plošného zemného výmenníka tepla s možnosťou prúdenia podzemnej vody v rovnakej vrstve. Vďaka týmto numerickým štúdiám a výsledkom dynamických tepelných modelov, každá prípadová štúdia obsahuje rozloženie teplôt v zemine, výstupné teploty z výmenníka a vlastný čiastočný záver.
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Monitoring the Influence of ceramic bond on the properties of insulating refractory materials
Friček, Jakub ; Kovář,, Pavel (referee) ; Nevřivová, Lenka (advisor)
Thermal insulating refractories are an integral part of each thermal unit since they reduce its energy consumption. The current phenomenon of saving in both environmental and financial aspects reflects in searching for such possibilities to produce at lower manufacturing and material costs. One of the possible ways is to valorise waste materials. The theoretical part then deals with the division of refractory materials, classification of thermal insulation refractory materials and manufacturing technologies. The experiment is focused on the production of insulating refractory materials made from plastic dough with a possibility of using sawdust and materials made by pressing mixture moist, with a focus on coal bottom ash. Both of these technologies will be tested for the possibility of modification by using mixed clays and of increasing the strength by using clays with lower sintering temperature.
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Nanofluids
Cabúk, Matej ; Kárník, Jan (referee) ; Fic, Miloslav (advisor)
Nanomaterials are phenomena of present time in science and technology. Nanofluids are fluids with original characteristics. In this thesis are presented production methods and effect of nanoparticles onto basic thermophysical properties. Applications of nanofluids are attractive. It is used mainly in heat transfer systems, but can be used in wide area. It can increase the performance a efficiency, save energy and money but also rescue human lives.
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Calibration task of experimental device for space technology testing
Lazar, Václav ; Horák, Marek (referee) ; Mašek, Jakub (advisor)
Diplomová práce se zabývá možnosti kalibrace experimentálního testovacího zařízení. Zejména se věnuje návrhu termálního matematického modelu popisujícího tepelné procesy uvnitř zařízení v průběhu měření tepelné vodivosti vzorku. První část práce je věnována seznámení se s testovacím zařízením, jeho limity a principem měření. Popisuje řešení třetí verze testovací komory, společně s nezbytnými úpravami, provedenými za účelem zajištění předepsaných simulačních podmínek. Zmiňuje také potřebu a důvody kalibrace. Druhá část je především zaměřená na návrh kalibračních vzorků a termálního modelu. Uvádí definované požadavky a konečné vlastnosti vyrobených vzorků. Matematický model prezentuje postup výpočtu zjištěných tepelných ztrát a poukazuje na možnosti jejich zpřesnění. Testování kalibračních vzorků bylo provedeno na nově zprovozněné třetí verzi testovací komory. Naměřené výsledky poslouží k ladění termálního modelu, nezbytného k dokončení kalibračního procesu, který umožní přikročení k další fázi testování v experimentální komoře.
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