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Flow visualization methods
Ďurdina, Lukáš ; Jedelský, Jan (referee) ; Lízal, František (advisor)
ĎURDINA, L. Flow visualization methods. Brno: Brno University of Technology, Faculty of Mechanical Engineering, 2010. 45 p. Thesis supervisor Ing. František Lízal. This thesis deals with fluid flow visualization methods with respect to their practical application possibilities. Chronological description of the historically valuable visualization experiments emphasises the role of visualization in the experimental fluid mechanics. A brief characteristic of the flow field contains mathematical description of the objects, which can be visualized. Visualization methods are divided into experimental and computer aided methods. Individual methods are ordered subsequently beginning with those with lowest requirements for equipment to the more sophisticated methods. Various techniques, which provide qualitative and quantitative description of the tested gas or liquid flow, are described. The overview for the choice of methods for various applications sums up the important facts from previous chapters. Description of a simple helium bubble flow visualization experiment realized in a lab can be found at the end of the thesis.
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Design of the methodology of measurement for evaluation of filtration efficiency of portable air cleaners and purifiers
Dvořáková, Michaela ; Bělka, Miloslav (referee) ; Lízal, František (advisor)
This work focuses on the research and comparison of several types of air purifiers. It clarifies the principles of filtration and describes the basic types of air purifiers. Part of this work is designed methodology of measurement for comparison of filtration efficiency and filtration rate. The experimental part of this work contains the measurement and comparison made for two types of air purifiers. Selected purifiers were De’Longhi AC230 with mechanical filters and ionic air purifier Ionic-CARE Triton X6. Within the framework of this work an experimental set-up was constructed in the home environment for the simulation of real conditions for the function of the air purifiers. The measurement results provide information about aerosol number concentration process during the measurements and evaluation of filtration efficiency of air purifiers.
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Visualization of air jet from ventilation outlet of a passenger car dashboard
Bečica, Radek ; Bělka, Miloslav (referee) ; Lízal, František (advisor)
Goal of this master´s thesis is to experimentally analyse air jet from ventilation outlet of a passenger car dashboard using smoke visualization and to describe this air jet. Air flow was set at 30 m3/h according to requirements from Škoda Auto s.r.o. from previous experiments on a similar ventilation outlet. First type of measuring rig which was developed for previous experiments was disassembled and replaced with a new modern measuring rig which is supposed to be used for next visualizations and experiments. Visualization was performed using smoke method and laser light plane. Air jet was photographed for five defined ventilation outlet adjustments and that for a jet to free space and for a jet flowing along a wall. The wall represented a front left door of a car. Results were processed by computer and presented as pictures and tables. Resulting angles were transformed to the main coordinate system of a car. Ventilation outlet functionality with respect to the air distribution in a car was evaluated afterwards.
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Face masks and respirators as protection against viruses and bacteria
Varga, Michal ; Mišík, Ondrej (referee) ; Lízal, František (advisor)
Pandemic caused by virus SARS-CoV-2 brought high attention to face masks and raised some questions about their filtration efficiency and performance affecting parameters such as high humidity, long term usage, fit factor, or possible decontamination methods for usage prolonging. In this thesis, mechanisms of SARS-CoV-2 transmission and structure and materials of face masks are firstly discussed. Then mechanisms of particle deposition on filter fibers are described. Subsequently standards of surgical masks, cloth masks and respirators are described and compared, with detail on carbon dioxide concentration under respirator. Nanoparticles and their possible effects on enhancing face mask parameters are briefly characterized. Then filtration efficiency and affecting parameters are evaluated. And finally possible decontamination methods for face masks reusability are summarized.
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Deposition of inhaled particles in a model of child lungs
Čederle, Jakub ; Pokorný, Jan (referee) ; Lízal, František (advisor)
This thesis presents a summary of research of deposition of inhaled particles in children’s respiratory system which was mainly conducted on realistic model of children's lungs. Experimental part introduces BUT model representing airways of 5-years-old child which served for measurements of regional deposition. Bachelor's thesis furthermore sums up basic knowledge of respiratory system and points out anatomical and physiological differences between children and adults in given field. There are described basic deposition mechanisms and their impact on aerosol therapy as well.
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Application of an anemometric hot-wire probe to the measurement of a velocity field downstream of an automotive ventilation outlet
Šíp, Jan ; Tuhovčák, Ján (referee) ; Lízal, František (advisor)
This diploma thesis deals with the research of the flow in front of the benchmark automotive vent. Using thermoanemometry, the velocity field in the area in front of the vent was measured in detail and the intensity of the turbulence was calculated. Computational fluid dynamics of the air flow from the vent was also performed using the STAR-CCM + program. In addition, the influence of the surrounding surfaces simulating the real environment of the automobile on the air flow from the vent was investigated. The diploma thesis contains the calculation of measurement uncertainty. The purpose of this thesis is to obtain complex data on the velocity field and to use them for validation of Computational fluid dynamics.
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Vizualization and optical measurements of two-phase flows for pressure-swirl atomizer
Janáčková, Lada ; Lízal, František (referee) ; Jedelský, Jan (advisor)
Tato práce se zabývá studií Simplex a SR verze původní trysky používané ve spalovací komoře malého proudového motoru. Pro lepší porozumění procesu rozprašování byl vyroben transparentní model obou trysek v měřítku 10:1. Tvorba spreje u tlakové vířivé trysky je komplexní proces dvoufázového proudění. Vnitřní a vnější proudění bylo zkoumáno pomocí Laserového Dopplerovského Anemometru a vysokorychlostní kamery při vstupních tlacích p = 0.5, 1.0 a 1.5 MPa s použitím kerosinu a p-Cymenu. Z hlediska vnitřního proudění byla provedena charakteristika vzdušného jádra a zkoumán vliv různých SFR hodnot na délku a průměr jádra. Dále byly objasněny rychlostní profily společně s jejich fluktuačními složkami vzhledem k Reynoldsovu číslu a použité kapalině. Také jednoduchý numerický model byl vyvinut k odhadu vnitřního proudění pomocí trackování částic. V případě vnějšího proudění byl zkoumán vliv vstupního tlaku na rozpadovou vzdálenost spreje a úhel kužele spreje.
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An advancement of heating plants system in Brno
Brabec, Vít ; Lízal, František (referee) ; Jaroš, Michal (advisor)
The content of this bachelor’s thesis is the examination of the advancement of heating plants system in Brno. The first part of the thesis introduces a brief overview of an eighty-year history of heating industry in Brno from the first ideas up to the current state. Next part closely describes the individual plants and the system of centralized heat supply. The last section compares heat supply through steam and hydrothermal pipe-line and its influence on the combined production of heat and electrical energy.
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Condensation aerosol generator - range of operation
Súkeník, Michal ; Chovancová, Michaela (referee) ; Lízal, František (advisor)
In this bachelor thesis I deal with condensation aerosol generator and its range of operation. This device is based on controlled heterogenous condensation and is widely used in different fields such as inhalation studies, testing filters or calibration of measuring devices. The primary aim of the thesis is to verify the quality of producing aerosol and the depandance on the operation conditions. I also deal with methods of generated aerosols as well as their statistical description.
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