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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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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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Influence of operational conditions on spray characteristics of twin-fluid atomizers
Zaremba, Matouš ; Lízal, František (referee) ; Jedelský, Jan (advisor)
This master’s thesis deals with measurement of spray characteristics of Effervescent atomizers intended for burning waste and heavy fuels. Atomizers were tested on cold test bench by means of Phase Doppler Anemometry. Spray characteristics were evaluated for many different regimes of pressure, temperature and Gas to liquid ratio. The aim of this measurement is to compare flow regimes and their influence on the quality of spray characteristics. The theoretical part describes basic fundamental principles of liquid atomization, effervescent atomization and principles of laser diagnostic methods. The practical part is engaged with improvements in test bench and setting up and optimization of the laser measuring system. Results contain visualization of spray, velocity profiles and drop size distribution in various operating flow regimes of the jet.
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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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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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Vizualization of liquid break-up from atomization nozzles
Janáčková, Lada ; Bělka, Miloslav (referee) ; Jedelský, Jan (advisor)
V oblasti mechaniky tekutin hraje vizualizace významnou roli. Fotografie poskytují vhled do zásad chování tekutin a obecně pomáhají k lepšímu pochopení fyzikálních procesů proudění. Tato práce se zabývá vizualizací rozpadu kapalin u rozprašovacích trysek. Práce popisuje základy rozpadu kapalin, stejně jako metody pro vizualizaci. Dále je v práci probrána a experimentálně testována analýza prvků ve vizualizačních metodách. Laboratorní testy byly provedeny na malé tlakové vířivé trysce určené pro spalování kerosinu v proudovém leteckém motoru a část experimentů byla provedena na tlakové spirálové trysce. Práce dokumentuje vliv zdroje světla na kvalitu fotografie. Chování spreje je navíc analyzováno pomocí makrofotografie se zaměřením na primární rozpad, který hraje hlavní roli v celém procesu tvorby spreje a sprejových charakteristik.
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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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Application of very thin matte coatings
Hruboš, David ; Mendřický, Radomír (referee) ; Koutecký, Tomáš (advisor)
This diploma thesis deals with matte coatings for optical 3D scanning. The aim of this thesis is to find a method of spraying the mixture of TiO2 and ethanol that would provide layer thickness beyond the measurable range of the 3D scanner. A spray gun allowing deposition of atomized mixture was design. The coatings created by this gun and by airbrush gun, which is commonly used for this purpose, were compared. The matting effect, thickness and the influence of used TiO2 particles were investigated in the coatings. The paper shows method of applying coatings that ensure sufficient matting of the surface for scanning purposes, and simultaneously have thicknesses that should not affect scanning results.
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The influence of atomizing media on the quality of the combustion of liquid fuels
Bojanovský, Jiří ; Skryja, Pavel (referee) ; Bělohradský, Petr (advisor)
The aim of the present work was to experimentally investigate the influence of atomizing medium on combustion properties of methyl-ester of rapeseed oil. The experiments were carried out in a water-cooled horizontal combustion chamber. The pneumatic atomization using effervescent atomizer was used in test. As atomizing medium compressed air and superheated steam was chosen. The tests were performed at GLR = 15, 20 and 25 %. The experiments were focused on the investigation of the flame characteristics, quality of combustion, emissions, temperature of flue gas, distribution of heat fluxes and stability of combustion. Results revealed that atomization by compressed air is more efficient (approximately by 6 %), on the other hand it leads to higher NO emissions (for 15 mg/mN3 due to higher in-flame temperature).
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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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