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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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Testing of a transparent model of a pressure-swirl nozzle
Sapík, Marcel ; Pech, Ondřej (referee) ; Jedelský, Jan (advisor)
The aim of the thesis is to put a transparent scaled PMMA model of the pressure swirl nozzle into operation, which includes, the selection of working fluids and the preparation of a test set to allow measurements using optical methods (LDA, PDA, PIV, high-speed visualization). The theoretical part describes the basic theory of atomization, optical measurement methods and deals with the problems of optical transition in optically complex systems. It also includes an extensive search for transparent liquids and materials of enlarged models that have been used in experiments, which often aim to match light refractive indices between these materials. In the practical part, attention is paid to the preparation of the test set and tests of chemical effects of several selected liquids on PMMA material are conducted, including a summary of experience with their use, as there was a permanent damage to the material. Several LDA measurements followed, using kerosene, p-cymene, 1-bromonaphthalene and water, evaluated the effect of the refractive index difference on the results. It turned out that no observable influence occurred if the refractive index difference between the nozzle material and the liquid was small. In addition, a visualization of internal flow through a high-speed camera was made. The practical part closes the static pressure measurement in the nozzle chamber, where the pressure ratio was measured on the walls of the chamber as well as on its axis. The measurement confirmed that the pressure on the chamber walls is constant and varies with the distance from the chamber axis.
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Study of surface coating possibilities for 3D scanning purposes
Franke, Jakub ; Mendřický, Radomír (referee) ; Koutecký, Tomáš (advisor)
This diploma thesis deals with matte coatings for 3D scanning purposes. The coatings are made with spray gun which uses a vibrating membrane atomizer and air blow gun. A suspension of titanium dioxide and alcohol is used as a coating material. This thesis describes the effect of the spray gun process parameters on the deposited coatings. These include, for example type of the coating suspension or setup of the blow gun. Phase Doppler Anemometry was used to measure spray characteristics. Deposited coatings were measured with profilometer and scanned with 3D scanner to study their thickness and effect on the results of 3D reconstruction. The result of this work was the coating with thickness below 1 µm with good optical properties for 3D scanning purposes. Standard deviation of the captured point cloud from the reference plane was below 0.0011 mm.
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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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Microalgae harvesting
Drozd, Jiří ; Naď, Martin (referee) ; Lošák, Pavel (advisor)
This work describe microalgae and their properties. Within the scope of the work, a research was conducted on the utilized microalgae and the possibilities of cultivation in the Central European region were examined. Furthermore, harvesting and drying methods for microalgae were analyzed, and an experiment was conducted using a promising spray drying method. The research revealed the properties and potential uses of microalgae. Various types of microalgae, their nutritional values, and possibilities of application in a wide range of fields were investigated. The cultivation possibilities of microalgae in the Central European region, including the utilization of wastewater and renewable energy sources, were also examined. Harvesting and drying methods for microalgae were analyzed, considering the advantages and disadvantages of different techniques such as flocculation, centrifugation, and spray drying. An experiment utilizing the spray drying method was conducted, and the results showed that this method is effective and enables the achievement of high quality and purity of dried microalgae. The work also explores the possibilities of further development and utilization of microalgae. It describes the potential use of microalgae as food supplements and as alternatives to traditional protein sources. Additionally, the potential applications of microalgae in the pharmaceutical and cosmetic industries were mentioned. In conclusion, this work provides information on the utilization of microalgae and the methods of cultivation, harvesting, and drying. The results suggest that microalgae have great potential for further development and utilization in various industries.
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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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A novel AAS atomizer based on a dielectric barrier plasma discharge
Novák, Petr ; Kratzer, Jan (advisor) ; Kanický, Viktor (referee)
Atomization of arsine in a novel hydride atomizer for atomic absorption spectrometry (HG-AAS) was thoroughly optimized. This plasma atomizer is based on a dielectric barrier discharge (DBD). Sensitivity and detection limit reached 0.48 s ng-1 As and 0.16 ng ml-1 As, respectively, under optimum atomization conditions (Ar discharge using a flow rate of 60 ml min-1 Ar, DBD power 17 W). Analytical figures of merit reached in DBD are comparable to those found in an externally heated quartz tube multiatomizer (MMQTA) that was chosen as a model of conventional approach to hydride atomization in HG-AAS. An extent of interferences (Se, Sb, Bi) during As determination was investigated comparing both MMQTA and DBD atomizers. The later one was found to be more resistant towards interferences. A simple preconcentration of As in a DBD atomizer was reached after oxygen introduction into the Ar plasma in the DBD resulting in analyte retention in the atomizer followed by its volatilization once the oxygen flow is switched off. Preconcentration efficiency of 100 % was reached and detection limit improvement by a factor of ten was achieved (0.01 ng ml-1 As, preconcentration period 300 s).
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HG-AAS with atomization in a dielectric barrier plasma discharge: method optimization and analytical applications
Zurynková, Pavla ; Kratzer, Jan (advisor) ; Kanický, Viktor (referee)
The aim of this diploma thesis was to optimize in detail atomization conditions for antimony hydride in a novel plasma atomizer based on a dielectric barrier discharge (DBD) with atomic absorption spetrometric detection. Argon was found as the best DBD discharge gas employing a flow rate of 50 ml min-1 Ar while the DBD power was optimized at 30 W. Analytical figures of merit including interference study of As, Se and Bi have been subsequently investigated and the results compared to those found in an externally heated quartz tube atomizer (QTA). The limit of detection reached in DBD (0.15 ng ml-1 Sb) is comparable to that observed in QTA (0.14 ng ml-1 Sb). Finally, possibility of stibane preconcentration in a DBD atomizer was studied. Preconcentration efficiency of 102 ± 6 % was found under optimized conditions.
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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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Study of surface coating possibilities for 3D scanning purposes
Franke, Jakub ; Mendřický, Radomír (referee) ; Koutecký, Tomáš (advisor)
This diploma thesis deals with matte coatings for 3D scanning purposes. The coatings are made with spray gun which uses a vibrating membrane atomizer and air blow gun. A suspension of titanium dioxide and alcohol is used as a coating material. This thesis describes the effect of the spray gun process parameters on the deposited coatings. These include, for example type of the coating suspension or setup of the blow gun. Phase Doppler Anemometry was used to measure spray characteristics. Deposited coatings were measured with profilometer and scanned with 3D scanner to study their thickness and effect on the results of 3D reconstruction. The result of this work was the coating with thickness below 1 µm with good optical properties for 3D scanning purposes. Standard deviation of the captured point cloud from the reference plane was below 0.0011 mm.
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