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Measurement of spray characteristics using optical measurement methods
Ďurdina, Lukáš ; Otáhal, Jan (referee) ; Jedelský, Jan (advisor)
Diplomová práce se zabývá měřením charakteristik sprejů dvou tlakových vířivých trysek pro spalovací komoru malého turbínového motoru na zkušebním stavu za studena pomocí metod Particle Image Velocimetry (PIV) a fázové Dopplerovské anemometrie (PDA). Cílem měření bylo stanovit a porovnat charakteristiky sprejů obou trysek. Výsledky měření mají objasnit rozdílnost chování trysek za provozu a možný dopad na proces spalování. Úvodní teoretická část pojednává o základních fyzikálních principech atomizace kapalin, konstrukci a oblasti uplatnění tlakových vířivých trysek a o principech laserových diagnostických metod použitých při experimentálním měření. Nasledující část popisuje návrh a montáž zkušební trati a dalších zařízení navržených pro experimentální měření v této práci. Experimentální část se zabývá nastavením parametrů měřícího systému a zpracováním dat. Výsledky měření zahrnují vektorová rychlostní pole, axiální rychlostní profily a distribuce velikosti kapek pro různé provozní podmínky obou trysek.
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Unsteadiness in sprays of effervescent atomizers
Beinstein, Zbyněk ; Volavý, Jaroslav (referee) ; Jedelský, Jan (advisor)
Master thesis focused on the research of the effervescent atomizers. Effervescent atomizers belong to a group of two-phase atomizers, which are often used in combustion applications. Right there in combustion applications, the degree of the stability sprays has a significant impact on combustion efficiency and exhaust gas emissions. The main aim of this work was to asses the level of spray unsteadiness depending on the atomizer design and its operating mode. The effect of construction was studied on the diameter and length of mixing chamber, and then on the size, number and location of aeration holes. Seventeen specific variants of the atomizer were constructed by different combinations of these design parameters. Each of these variants was measured in three operating modes, which were represented by a liquid pressure at the inlet to the atomizer and gas-to-liquid mass flow ratio (GLR). To evaluate the level of spray unsteadiness was used a methodology, which compares the ideal element´s distribution into the interparticle time bin, defined for the ideal (stable) spray, with the experimentally observed distribution. The laser measurement system P/DPA (Phase Doppler Particle Analyzer) was used to determine the experimental interparticle distribution. The result of the comparison of the ideal and the experimental distribution was the parameter , which expresses the level of spray unsteadiness for a specific atomizer and operating mode. With that parameter it was possible to compare the individual atomizers and determinate to the benefit of various construction´s correction of the atomizer. The results showed the recommendation for the modifications of the atomizer, creating a spray with a minimum level of spray´s unsteadiness. For the surveyed atomizer and his individual costruction´s variations the drawing was made.
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Dancing liquid - vibration eigenmode shapes of liquids
Urban, Ondřej ; Pochylý, František (referee) ; Rudolf, Pavel (advisor)
This bachelor's thesis deals with phenomena connected with vertically oscillating liquid layer, particularly with Faraday waves and liquid atomization. More in detail it deals with the linear mathematical model for vertically oscilating inviscid and incompresible liquids by Benjamin & Ursell (1954). It also presents the appearance of these and other phenomena connected with liquid vibration in practical applications. Furthermore, results of experiments are presented. Their aim was to find some eigenmode shapes using the linear model and also to document some of their properties. Final part is aimed to the design of an experimental device for visualization of vibration eigenmode shapes of liquids.
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Quality of fuel atomization from small pressure-swirl atomizers
Malý, Milan ; Broukal, Jakub (referee) ; Jedelský, Jan (advisor)
Tato bakalářská práce se zabývá měřením charakteristik spreje z tlakové vířívé trysky za použití fázového doplerovského analyzátoru. Cílem měření bylo stanovit a porovnat charakteristiky spreje za použití různých kapalin a různých režimů tlaků a rozhodnout, jestli je možné nahradit kerosin biopalivy z pohledu kvality atomizace. Teoretická část se zabývá základy rozpadu kapalin z tlakových vířivých trysek a principy laserové anemometrie. Experimentální část popisuje testovací trať, provozní podmínky a nastavení experimentu. Výsledy obsahují vizualizaci spreje, velikostní rozložení kapek uvnitř spreje, profily rychlosti a Sautrova středního průměru za použití různých provozních podmínek jako je různá vzdálenost od trysky, rozdílný vstupní tlak a různé kapaliny.
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Recent designs of twin-fluid atomizers
Dostal, Jan ; Golitko, Lukáš (referee) ; Jedelský, Jan (advisor)
This thesis deals with design of twin-fluid atomizers. The main task is to categorize atomizers, mainly to sort and describe recent types of twin-fluid atomizers. The thesis describes operating advantages/disadvantages, complexity of designs of selected nobles. The thesis compares nozzles with the quality and method of atomization. Based on the knowledge was created technical drawings of two selected nozzles with internal mixing.
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Combustion of renewable liquid fuels
Shylin, Ivan ; Skryja, Pavel (referee) ; Kermes, Vít (advisor)
The main task of the thesis is the survey of renewable fuels available in Czech Republic and in the world, and to compare them with present petroleum products. In the first part of the thesis important properties of the liquid fuels are defined along with corresponding national and international standards. In the next chapters petroleum and renewable liquid fuels are presented. The second part of the thesis is concentrating on atomization. In the conclusion there is a summarization of difficulties with renewable fuels.
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Atomization mechanisms of liquid fuels
Buzík, Jiří ; Bělohradský, Petr (referee) ; Broukal, Jakub (advisor)
The bachelor thesis deals with the atomization of liquid fuels and their atomizers and mechanisms which are concerned in atomization. The main purpose of this thesis is to describe the problems that are connected with the atomization. The author gives information about the primary and secondary decomposition of liquid. One part of the thesis is the software which focuses on the statistic evaluation and comparison of information which are performed by available experiments and numeric calculations.
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Kapky v plynných proudech: jejich původ, měření a separace
Hrubý, Jan
We review some interesting aspects of the origin of the droplets by atomization or vapor-liquid nucleation, measurement of droplets by light scattering, and separation of droplets. Production of small droplets around 10 microns requires high pressure spraying or two-phase nozzles with help of high pressure gas. Smallest droplets – from 1 nm – can be formed by vapor-liquid nucleation processes. Application of the constant angle Mie scattering method enabled measurement of fast growing droplets in the range of 300 nm to 2000 nm. Examples of separation of droplets using inertial effects are given.
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