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SMV-2023-51: Cryogenic attributies of selected products
Srnka, Aleš ; Hanzelka, Pavel ; Krutil, Vojtěch
Thermal flows between hotter and colder parts of special components of cryogenic machines during different border temperatures were measured. Experimental results were compared with theoretical calculations. Onward was tested vacuum leak of different types of cryogenic seals up to pressure 30 bar. Research reports were passed on to contractor. Measurements were conducted in apparatuses, newly designed and developed in the ÚPT AV ČR, v. v. i.
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Thermal conductivity measurements
Herr, Tomáš ; Šedivá, Soňa (referee) ; Beneš, Petr (advisor)
This bachelor thesis is focused on measurement of thermal conductivity and description of measurement principles by different methods. These methods are divided into stationary, unsteady, with linear sources and with point sources. Partially is this thesis dedicated to the research of the market with devices measuring thermal conductivity, other part is creating an overview of Czech national norms. The practical part is dedicated to an experiment proposal, realization of measurement itself and final validation of results. The principle of the experiment is based on non-stationary measurement made by line-linear source which is working on pulse mode.
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Determination of thermophysical properties of scale layer on steel at high temperatures
Ondruch, Tomáš ; Votavová, Helena (referee) ; Pohanka, Michal (advisor)
The thesis deals with thermophysical properties of scale layer on steel and their determination at high temperatures. The first part summarizes fundamental characteristics of scales, it is also devoted to principles of heat transfer with emphasis on heat conduction. The following text presents current state of research on scales’ thermophysical properties. Subsequently, the thesis aims to experimental measurement of thermophysical properties by use of laser flash method and conducted measurement is described, as well. The following chapters present a finite-element numerical model of the measurement aparatus and computation technique for determination of scales’ thermophysical properties is explained. The obtained results are compared with available data and sensitivity analysis of selected model parameters is carried out.
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Thermal conductivity measurements
Sklenář, Milan ; Bejček, Ludvík (referee) ; Beneš, Petr (advisor)
This thesis focus on measurment of thermal conductivity by transient point heat source method and heat diffusion through materiál. There is described exemplar, measurement procedure and used devices. Thesis focus on verification of teoretical equations and effects of variables, which can affect accuracy of measurement.
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Structural optimization of the heat switch part
Zemek, Albert ; Mašek, Jakub (referee) ; Löffelmann, František (advisor)
This diploma thesis deals with the design of a structure for heat transfer path of miniaturized heat switch. The focus is on production using SLM additive technology. The aim is to assess the possibilities of using metal 3D printing on a part intended primarily for heat transfer. This work presents several concepts of structure arrangement, which are further analysed and evaluated. The results show the potential of additive technologies in this area and the proposed structures meet the heat transfer requirement according to the calculations used.
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The design of ETICS using insulation core made of aerated concrete
Machala, David ; Zach,, Jiří (referee) ; Drochytka, Rostislav (advisor)
This thesis deals with theoretical suggestions of contact self-supporting insulation system with an insulating core made of porous concrete. The text prepared knowledge about ETICS system, the properties of porous concrete are thoroughly described, including the history and the most often used technology for production of porous concrete. The conclusion is made by comparison of economical and thermal insulation criteria using optimizing calculation and the applicability criteria of proposed ETICS are stated.
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Flexible structure development for efficient heat transfer
Černoch, Jakub ; Lazar, Václav (referee) ; Mašek, Jakub (advisor)
Diplomová práce se zabývá teoretickými výpočty a návrhem struktury pro přenos tepla, která je součástí Miniaturizovaného tepelného spínače podle zadaných požadavků Evropské Kosmické Agentury. Základními parametry jsou nízká hmotnost a vysoká tepelná vodivost. Práce navazuje na spínač navržený firmou Arescosmo, který nesplňoval požadované limity zejména v oblasti hmotnosti a tepelné vodivosti. Pomocí teoretických výpočtů hmotnosti a tepelné vodivosti bylo ověřeno 49 variant ve třech základních konceptech – Mechanická struktura, flexibilní struktura složená z drátků a foliová struktura. Z hlediska tepelné vodivosti jako nejlepší struktury vycházejí ty, které jsou založené na použití ochranných kovových opletů. Z dostupných zdrojů byly rovněž navrženy technologie, které by bylo možné využít pro výrobu těchto struktur. Pro splnění požadavků, bude v další fázi projektu nutné vyrobit experimentální vzorky na kterých budou teoretické výpočty a vybrané technologie ověřeny.
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Study of the behavior of insulating materials in a high humidity environment
Havelka, Jindřich ; Peterková, Jitka (referee) ; Zach, Jiří (advisor)
Extruded polystyrene (XPS) is presented as non-absorbent material and it is applied in building construction with high moisture, such as inverted roof. The reason for that is a very good ratio of thermal and mechanical properties and it is used in moisture-loaded applications due to the closed pore structure and high diffusion resistance factor, which are declared by the manufacturers. Long-term experience and studies show that XPS accumulates moisture during long-term exposure in an environment with high humidity. A long-term water absorption test at full immersion for 84 days has been proposed to better illustrate the trend of increasing water absorption. A total of 6 products from different manufacturers that are recommended for inverted roof application, were tested. All tested XPS products have reached high amount of water absorption. The main goal was to map the real properties of XPS at high humidity loads. It was found that each product showed a different degradation of thermal conductivity at the same volume moisture value. Furthermore, there was found the connection between the surface structure and amount of water absorption. Products with waffle structure had higher humidity than products with a fine structure.
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Optimization of the printed circuit board for power LED
Schenk, David ; Klíma, Martin (referee) ; Ing. Josef Vochyán, Ph.D., ALCZ Jihlava (advisor)
This diploma thesis deals with the problems of heat transfer on printed circuit boards. The first part consists of a theoretical analysis of the principles of conduction of heat in different environments, comparing the properties of common type’s base materials for PCBs in terms of thermal properties and focuses on heat transfer from the chip. In the following part they are general information about the program ANSYS ® Workbench ™. Next part consists of the basic designs of PCBs and their improving. PCBs thermal properties for different configurations are verified with calculations, simulations and practical measurements. In the last part there are created design recommendations for PCBs design based on the comparison of the results of initial proposals and proposals to improvements.
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