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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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Determination of droplet velocity and size from high-speed imaging
Juroška, Jan ; Cejpek, Ondřej (referee) ; Malý, Milan (advisor)
In this bachelor thesis there was created a method of getting velocity and size of droplets form a video using computer vision. Velocity is obtained via PIVlab toolbox in matlab, wich uses Particle Image Velocimetry. Size is obtained via matlab code. Theoretical basis on wich this code was written is included in the theoretical part of this thesis. In practical part of this thesis, accuracy of this method was evaluated and the method was applied on a video of a real spray droplet flow.
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Automotive ventilation system - comparison of an influence of boundary conditions on flow from various types of ventilation outlets
Brdečko, Radim ; Pokorný, Jan (referee) ; Lízal, František (advisor)
Diploma thesis deals with a research of the flow in front of three different automotive vents. The velocity field and intensity of the turbulence was measured in detail, using thermoanemometry. After that the same data was measured with PIV method and validation was performed. The difference between achieved data was investigated. The design among the vents was also investigated, because it’s fundamentally affects the air flow. The purpose of this thesis is to obtain data about the velocity field using two methods and their subsequent use to validate numerical simulations, which will be performed in the future. The diploma thesis also contains the calculation of measurement uncertainty.
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Computational simulation of air flow in a gas burner
Waloszek, Jan ; Rudolf, Pavel (referee) ; Vondál, Jiří (advisor)
This work is focused on computational modelling of a flow in a burner. The main objective is to provide a complex comparison of the results obtained through several approaches to modeling, on different computational grids and also using different turbulence models. Experimental measurement data are used for validation. Numerically obtained data are compared to each other and to experimental data. The method of Proper-Orthogonal Decomposition is also applied on the calculated data. The greatest benefit of this work is providing a wider view on the swirling flow modeling in burners and the results obtained here will help to better understand the behavior of stated models for tasks of this kind and their potential for modelling combustion in furnaces.
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Methods for determining aerodynamic properties of vehicles
Páleš, Patrik ; Blaťák, Ondřej (referee) ; Čavoj, Ondřej (advisor)
The aim of the bachelor’s thesis is a description of methods being used for measurements of aerodynamic characteristics of automobiles. The exact determination of the aerodynamic characteristics requires sophisticated testing equipment and advanced engineering procedures. The research comprises several approaches. Computational fluid dynamics (CFD) is based on turbulent models application such as RANS, LES and DNS. Pressure distribution on a vehicular body surface and an air flow along the vehicle are monitored in wind tunnels. Flow visualization is carried out by optical (PIV, LDA) and non-optical methods. Experimental road testing methods are focused on multiple parameters including a vehicle directional stability, its cross-wind sensitivity, engine cooling system and many others.
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Comparison of speed measurement by hydrometric propeller and laser anemometer
Kosík, Ondřej ; Haluza,, Miloslav (referee) ; Zubík, Pavel (advisor)
This final thesis deals primarily with the comparison of two calibration approaches. It determines the degree of mutual agreement and tries to answer the reasons of their deviations. This agreement was measured by the LDA method. It was found that the calibration approach based on the reference framework of values of the previous bachelor thesis differs systematically from the calibration using calibration equations obtained from certified laboratories by -2 %. The causes of this deviation were investigated using LDA and PIV. Although a significant number of measurements were performed, all tested hypotheses were refuted and therefore it was not possible to determine their cause.
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Optimizing of air distribution in schools
Cigánková, Kristýna ; Šíma, Jiří (referee) ; Šikula, Ondřej (advisor)
The thesis deals with the issue of indoor air quality of schools and kindergartens. It focuses particularly on the inadequate ventilation and the application of forced ventila-tion in these types of buildings. The proposed solution is applied to a kindergarten in Kuřim. Measurements of the C02 concentration levels were performed in the presence and absence of air conditioning. To elaborate the proposed solution a simulation was made using a software called ANSYS Fluent. Input values for the simulation were obtained from an experimental measurement of a ventilation diffuser made by a company called Climecon ROX using the PIV method. This diffuser was then installed in the kindergarten. The measure-ments were carried out in the framework of the project the experimental validation of numerical models of the air flow in buildings marked with FAST-S-6-3387.
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The Design and Aerodynamic Testing of DPIK Probe
Procházka, Pavel P. ; Barraclough, V. ; Skála, Vladislav ; Uruba, Václav
The isokinetic probe used to detect the liquid phase drift from the cooling tower is presented here. The main motivation is costs reduction that arises during standard drift measurements. The probe was developed in the framework of the grant project between private company 4Jtech and Institute of Thermomechanics. The aerodynamic design and optimization of this probe should fulfill one important criterion – to capture the droplets from the drift with maximal efficiency. Kalorimetric principle is then used to evaluate the amount of trapped water. Standard PIV (Particle Image Velocimetry) measurement technique and modified IPI (Interferometric Particle Imaging) methods were used to measure the flow field topology and the particle size distribution, respectively.
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Simulations of Photobioreactors from Hydrodynamics and Mass Transfer Point of View
Rebej, Miroslav ; Turek, Vojtěch (referee) ; Jördening, Alexandra (referee) ; Jegla, Zdeněk (advisor)
Simulations of photobioreactors with microalgae-specific cultures is a field that connects microbiology with the multiphase fluid dynamics. With microalgae cultivation, it is necessary to account various phenomena, e.g., multiphase hydrodynamics with water, CO2 bubbles and microalgae, multiphase species mass transfer, radiation transport, light attenuation, growth and culmination of microalgae and their effect on fluid properties. Computational model presented in this doctoral dissertation thesis links multiphase hydrodynamic model and the species mass transfer model. In the thesis, there is an overview of applicable computational models for the given types of photobioreactors. The multiphase hydrodynamic model and the species mass transfer model then draw from this overview. Next, the accuracy of these sub-models was compared with laboratory experiments. As a result, the developed computational model of the photobioreactor can be further extended with other sub-models, i.e., the irradiation model and the biomass growth model.
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