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Internal Flow of Spill-Return Pressure-Swirl Atomizers
Malý, Milan ; Honus,, Stanislav (referee) ; Lozano, Antonio (referee) ; Jedelský, Jan (advisor)
Tlakové vířivé trysky (TVT) jsou používané v mnoha aplikacích, kde je potřebná velká plocha kapek nebo kde povrch musí být nanesen kapalinou, např. spalování, sprejové chlazení nebo nanášení barev. Parametry spreje z TVT jsou úzce spojené s jejich vnitřním prouděním. Obtokové trysky vylepšují koncepci klasických TVT přítomností otvoru, skrz který může kapalina odtékat zpět do nádrže. Díky této koncepci je možné regulovat vstřikovací množství kapaliny změnou průtoku tímto otvorem, zatímco se ve vířivé komůrce udržuje vysoký tlak, který zaručí dobrou kvalitu spreje. Obtokové trysky byly historicky málo prozkoumány a jejich vnitřní proudění nebylo studováno téměř vůbec. V této práci je popsáno vnitřní proudění několika obtokových trysek jak experimentálně, tak numericky. Tato data jsou následně korelována s měřenými vlastnostmi spreje. Výsledky ukazují, že přidání obtokového otvoru silně ovlivní vnitřní proudění i v případech, kdy obtokem neproudí žádná kapalina. V některých případech se vůbec nezformuje vzdušné jádro a tím se destabilizuje výtok z trysky, čímž vznikne nestabilní sprej. Mimoosé obtokové otvory generují a stabilizují vzdušné jádro, což pomáhá formovat kapalinovou stěnu a vysoce kvalitní sprej. Nicméně některé konfigurace změnily charakter rozpadu kapalinové stěny, což se projevilo i na kvalitě spreje. Navíc regulační schopnost a stabilita spreje závisí na vzdálenosti obtokových otvorů od osy vířivé komůrky. Na závěr byla upravena neviskózní teorie, která analyticky popisuje vnitřní proudění v TVT, tak aby byla aplikovatelná i na obtokové trysky. Pomocí tohoto přístupu byla odvozena teoretická predikce výtokového součinitele a velikosti vzdušného jádra v závislosti na obtokovém poměru (SFR). Zároveň byly pro obtokové trysky upraveny empirické korelace původně odvozené pro TVT. Tato práce přináší nový vhled k porozumění vnitřního proudění obtokových trysek a její výsledky najdou uplatnění při jejich návrhu.
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Design of ventilation system in apartment
Doležel, Pavel ; Malý, Milan (referee) ; Pech, Ondřej (advisor)
Topic of bachelor thesis is aimed to solving of ventilation with heat recovery in flats. Introduction is deals with analysis of current ventilation units and attachments specified for this purposes. Next chapters are devoted to design different options of units, pipes systems and kinds of regulations for assigned flat. In last part of work are evaluated costs invested to instalation, maintanance and running of used units. At the end of the work are put drawings of individual solvings including bill of materials.
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Injection systems of rocket engines
Vrbica, Kryštof ; Cejpek, Ondřej (referee) ; Malý, Milan (advisor)
This bachelor thesis deals with liquid propelled rocket engine injector design. The theoretical part describes the categorisation and principles of the function of a rocket injector element. The following research part provides an in-depth examination of the most often used injectors including their possible versions. This section concerns coaxial, pintle and impinging injectors. The emphasis is laid on discharge coefficient, spray behaviour and definition of the optimal injector geometry for high-quality atomization. The thesis is concluded with a design of test injectors and their experimental comparison. Coaxial and two version of impinging injector are tested with regards to spray behaviour, their discharge coefficients, Sauter mean diameter and droplet velocity. Design drafts required for production are included in this thesis.
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Transparent packing for optical experiments in Rotating packed beds
Hájek, Jiří ; Elcner, Jakub (referee) ; Malý, Milan (advisor)
Given the amount of energy and industrial processes that produce carbon dioxide, it is necessary to reduce the amount of CO2 emitted into the atmosphere. One option is to capture and store the carbon dioxide produced, called CCS (Carbon Capture and Storage). For effective capture, a rotating packed bed absorber can be used, which works on a similar principle to a static absorption column, but the driving force of the liquid is not gravity but centrifugal force. This allows the device to be very compact in size. To optimise the absorption process, it is necessary to analyse the nature of the flow inside the absorber. This work focuses on the design and testing of a unique packed bed with stainless steel wire filling and transparent plexiglass support parts for optical analysis of the internal flow. Using a high-speed camera, the nature of the fluid flow was recorded under different operating modes. The changed parameters were the operating speed, which ranged from 300 to 1,800 rpm, and the velocity of the fluid flow, ranging from 1.25 to 11.5 m/s. When evaluating the nature of the flow, attention was paid mainly to the inner part of the packing fill, where the droplet size and velocity change the most. However, the assessment of the flow across the entire packing was also evaluated. Recommendations for the choice of operating modes, evaluation of droplet size and, finally, the empirical correlation for the calculation of the absolute liquid velocity at the inner part of the packing is also discussed.
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Design and verification of lab-scale spray column for CO2 capture
Veselý, Filip ; Bělka, Miloslav (referee) ; Malý, Milan (advisor)
The concept and design of the lab-scaled spray column for CO2 capture which is capable of using optical measurement technologies and provides variations of experimental conditions is crucial to research CO2 absorption using sprays. This thesis is focused on the design of the column and all necessary components. Furthermore, there are discussed experimental conditions and measurement technologies. It provides deep look at velocity profile adjustments and efficiency of the absorption for MEA and aqueous ammonia. There is a discussion about each configuration and its results including design adjustments suggestions.
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Financial return of home photovoltaic power plant
Jančík, Josef ; Malý, Milan (referee) ; Mauder, Tomáš (advisor)
This thesis if focused on return on ivestment evaluation of a photovoltaic system of residential house. The calculation is made for photovoltaic system with and without accumulation and in combination with other alternative source – heat pump. The costs of instalation and working of new systems are then compared between each other and with the cost of working of a current system without photvoltaic.
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Influence of manufacturing process and precision on quality of liquid atomization from pressure-swirl atomizers
Lebeda, Kryštof ; Cejpek, Ondřej (referee) ; Malý, Milan (advisor)
The thesis deals with the effects of manufacturing inaccuracies and manufacturing method on the spray quality of pressure-swirl atomizers. First, basic principles of atomization are outlined. In the next section, observed atomization parameters of pressure swirl atomizers are discussed. This is followed by a research of available studies investigating influence of inaccuracies and manufacturing methods on selected parameters. In the practical part evaluation of measured data of pressure-swirl atomizers with defects at discharge orifice, different surface roughness and atomizers made by 3D printing was carried out. Skewness and misalignment of discharge orifice significantly reduced spray quality. No effect of surface roughness for conventionally manufactured nozzles was found. The use of 3D printing for nozzle production resulted in a deterioration of atomization fineness. Chamfering of dicharge orifice promoted larger spray cone angle but did not affect the atomization fineness.
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Concept of the Noahide Laws
Malý, Milan ; Holubová, Markéta (advisor) ; Nosek, Bedřich (referee)
Annotation: The seven Noahide laws represent a divine non-Jewish complementary to Jewish law. This thesis has been looking for an answer to the question about concept of those laws, their content, intentions and contemporary use. The main method is analysis of original sources and investigating their mutual relations. Comparison of contemporary guides is also included.
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