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Modeling of airflow through the human vocal tract during voice production
Kučera, Marek ; Hájek, Petr (referee) ; Švancara, Pavel (advisor)
This bachelor's thesis deals with computational modeling of air flow through the human vocal tract during voice production. In the theoretical part, the anatomy of the respiratory system, the function of the human vocal folds, the biomechanics of the human voice and the flow theory are briefly described. Subsequently, an overview of approaches to computational modeling of voice production is presented. The practical part describes the creation of 2D models of the trachea and vocal tract with different settings of the vocal folds. A suitable mesh of finite volumes was created. Stationary flow was solved and analyzed in the ANSYS Fluent program. A suitable time step was determined for non-stationary flow and the results were subsequently analyzed. At the end, the non-stationary flow with the prescribed movement of the vocal folds is solved.
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Excessive pressure energy recovery in liquid transport systems
Luky, Samuel ; Bezdíček, Jiří (referee) ; Rudolf, Pavel (advisor)
Táto práca sa zaoberá využitím prebytočnej tlakovej enrgie vo vodovodných potrubiach a spôsobmi ako ňou produkovať elektrinu. V prvej časti sú zhrnuté všetky použitelné riešenia, to sú čerpadlová turbína, AXENT a STRAFLO turbína a turbína s protibežnými obežnými kolesami. Druhá časť je venovaná návrhu axiálnej turbíny pre špecifickú samosprávu mesta Ferlach v Rakúsku. Návrh je následne otestovaný pomocou zjednodušeného CFD výpočtu pomocou programu ANSYS fluent. Výsledky sú zhodnotené a ďalšie kroky na zlepšenie sú navrhnuté.
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Dispersion of particulate matter pollution from electric vehicles in urban areas using CFD
Lipka, Jakub ; Pospíšil, Jiří (referee) ; Linda, Jakub (advisor)
There is an opinion across the society, that electric vehicles (EV) are emission-free alternative to vehicles using internal combustion engines (ICEV). This is not true. Although electric vehicles do not produce emissions connected to internal combustion, they still produce non-combustion emissions that are emitted into surrounding air. Non-combustion emissions in question are brake wear particles (BWP), tire wear particles (TWP) and road wear particles (RWP). These emissions, due to EV’s greater mass, tend to be higher compared to ICEVs. Therefore, in this thesis, model of dispersion of non-combustion emissions generated by EVs was created using CFD consisting of two models – airflow model around EV and particle dispersion model. It was found that those emissions are captured and distributed by airflow, mainly thanks to vortices generated in the wake zone behind the vehicle. Those particles can be suspended up to 1,9 m into the air and up to 2,5 m laterally away from the vehicle. Thanks to that there is a risk of pedestrian inhaling air with high concentration of those particles in places near roads like pavements.
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Design modification and CFD simulation of the filling valve
Klíma, Štěpán ; Kohút, Jiří (referee) ; Klas, Roman (advisor)
This thesis deals with the design of a filling valve guide using a metal 3D printing method for application in a hydraulic press. The production of a filling valve guide using traditional forms of manufacturing in terms of labour, production, technology and time-challenging processes and the metal 3D printing method can help to overcome some of these challenges. The introduction of this paper is concerned with explaining the function of filling valves in the hydraulic press mechanism and a brief introduction to valve guide manufacturing technologies, including metal 3D printing technology. This is followed by an explanation of the new design in terms of the technology used. A strength analysis using FEA is then developed to determine the functionality of the valve guide and to optimise its shape. In this section, an iterative procedure was used to reduce the reduced stress in the ribs to 68 % of the reduced stress of the original design by changing the valve guide geometry. At the same time, a theoretical introduction to FEM is written, including an explanation of the non-linearities in FEM. This is followed by a comparison of the hydraulic losses due to oil flow through the original valve and the valve with the modified valve guide. Similar to the FEM chapter, a theoretical section is also written introducing CFD, mesh generation for CFD and turbulence models.
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Thermoregulatory generator for a small combustion boiler
Kováč, Samuel ; Babička Fialová, Dominika (referee) ; Jecha, David (advisor)
With increasing requirements for the full use of the heat that is produced, the effort to use waste heat is also increasing. One of the possibilities for such heat is the direct conversion of thermal energy into electrical energy. A device called a thermoelectric generator (TEG) is used for this purpose. Nowadays, it is in the constant development part of their existence. The limiting active substance is the known thermoelectric materials. Nevertheless, this technology finds its use in practice. This work is characterized by the basic principles of thermoelectric conversion, the materials discovered so far and their efficiency, and lastly the TEG patients in a lump wood gas boiler. The main idea of the project, which is ongoing in cooperation between BUT and Ecoscroll, is the development of a small combustion device, a household boiler for wood fuel with manual attachment, which would meet the emission parameters of the Ecodesign Directive 2009/125/EC, can function independently of the connection to the electricity network.
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Quantitative comparison of used mesh for CFD software ANSYS Fluent
Koudelková, Kateřina ; Klas, Roman (referee) ; Štefan, David (advisor)
Creating a good computational mesh is one of the crucial activities in any CFD calculation. CFD software aim to make a mesh generation as simple and automated as possible, due to its time-demanding nature. ANSYS Fluent has introduced a tool for partially automatic mesh generation, a method called Mosaic mesh, which should ensure that the best type of mesh element is used in each part of the geometry for optimal results. Polyhexcore is the latest computational mesh generation method used by Mosaic mesh technology. This thesis aims to compare the Polyhexcore mesh with other types of computational meshes on an aerodynamic test problem.
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Vortex induced vibrations
Szarka, Beáta ; Pluskal, Tomáš (referee) ; Rudolf, Pavel (advisor)
Tato bakalářská práce se zabývá kmitáním vyvolaném vírami na různých průřezech. Teoretická část poskytuje přehled současných trendů výroby energie a představuje typ hydrokinetického sběrače energie VIVACE konvertor. Hlavním principem systému je odtrhávání víru a vznik Kármánové vírové stezky podél tělesa ponořeného do proudící tekutiny. Praktická část se zabývá vyhodnocením různých profilů podle sil působící na těleso, frekvencí a Strouhalového čísla pomocí 2D CFD simulací. Výstupem je výběr ideálního tvaru průřezu válce pro konvertor VIVACE.
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Air recirculation balance of the vehicle's cooling package
Macejka, Kamil ; Čavoj, Ondřej (referee) ; Vančura, Jan (advisor)
The focus of this thesis is to create an effective tool for quick analyses of hot air recirculation at the cooling package, wich is a significant factor that influences its effectivity, to evaluate this influence and to propose viable solutions for its mitigation. The theoretical part of the thesis is devoted to the description of the problem, review of existing scientific studies and introducing the mechanisms responsible for the studied phenomenon. The practical part contains an analysis of flow and thermal effects, whose outputs are used for developing an computational model with a graphical user interface. This model is further used for comparison of effects of various input parameters and based on its results the measures targeted on reduction of recirculation are designed, which are then evaluated using CFD methods.
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Use of fluidics systems in robotic applications
Eim, Jakub ; Parák, Roman (referee) ; Matoušek, Radomil (advisor)
The master's thesis deals with the design, production and testing of fluidic elements used for positioning parts in a robotic cell. The aim is to replace vibratory tables and feeders used in pick and place applications with the proposed fluidic solution. The review focuses on currently used products for feeding parts, fluidic oscillating nozzles and air knives. The practical part focuses on the development of fluidics elements using CFD simulations. The design of the 3D model of the robotic station with the implemented fluidic solution was carried out in Solid Edge. The robotic cell was programmed by a digital twin in the Epson RC+ simulation environment. Epson CV2 machine vision was implemented for picking positioned parts with the Epson C8-A1401S manipulator. Finally, the designed fluidics elements were successfully validated on a real robotic cell. The work is concluded by comparing the obtained results with vibration tables.
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