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Sensitivity increasing of gold determination by electrochemical volatile species generation with AAS detection
Vacek, Tomáš ; Hraníček, Jakub (advisor) ; Rychlovský, Petr (referee)
This thesis is focused on increasing the senstitivity of gold determination by electrochemical volatile species generation using two different types of electrolytic cells in continuous flow setting. Externally heated quartz tube atomizer was used as means of atomization and detection of gold with atomic absorption spectrometer. Generation parameters were optimized for electrolytic cell with an ion exchange (nafion) membrane. After selection of new cathode material (Cu) the carrier gas (Ar) flow rate was optimized, where an additional inlet of carrier gas was found to have possitive effect on increasing the sensitivity of determination of gold and efficiency of volatile specie transport to the atomizer. Experiments with Antifoam B showed possitive effect on generation, thus calibration was carried out for optimized experimetal conditions reaching detection limit of 0,53 mg.dm−3 . The efficiency of volatile specie transfer from liquid to gaseous phase was determined between 60 - 65 % by measuring the residual gold content in liquid waste by F-AAS method. Subsequently the effieciency of electrolytic generation of volatile gold specie with radioactive tracer isotopes and autoradigraphy was determined to 0,6 %. These methods confirmed adsorption of generated species on apparatus surface. Using ICP-MS as...
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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 13 mg/mN3 due to higher in-flame temperature).
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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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Design and construction of transparent nozzle for visualization and measurement of the internal flow
Sapík, Marcel ; Fojtlín, Miloš (referee) ; Jedelský, Jan (advisor)
This thesis deals with design and construction of transparent nozzle for research of internal flow of liquids. The objective was to design potential construction of the nozzle and make a manufacturing drawing. The theoretical part deals with basics of atomization including properties of liquids and describes basic optical methods for internal flow in a nozzle. In the research part of this thesis, a number of construction solutions has been picked to serve as an inspiration for the final shape of the nozzle. Its construction is elaborated in the last part along with a description of the process, a manufacturing drawing, and a visual documentation with a 3D model.
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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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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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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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