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Car cabin passive cooling system performance study
Viščor, Petr ; Hejčík, Jiří (referee) ; Fišer, Jan (advisor)
The work is focused on issue of passive cooling in a cabin of a car. The basic principles and mechanisms of heat transfer are described in the theoretical part and the quality of cabin environment in terms of thermal comfort and air quality is discussed as well. Next part of the work describing the principles of ventilation and air conditioning of cabins and possible methods of passive cooling are discussed. Passive cooling means decrease of temperature of cars interior, without need of energy supply from car battery, or fuel. The last part of the work includes numerical simulation of selected methods of passive cooling using the THESEUS-FE 3.0 software. Simulations were performed on model of Volkswagen Polo car and primarily were focused on testing of functionality of various methods of passive cooling.
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Numerical analysis of selected silicate based composites shrinkage
Drbušková, Magdaléna ; Vlk, Zbyněk (referee) ; Keršner, Zbyněk (advisor)
The thesis is divided into two main parts. In the first theoretical part is described the problems of shrinking including a comparison of Czech standard and Model Code 2010, Vol. 1. The second practical part of the master`s thesis is focused on the numerical analysis shrinkage primarily on the initial stage of this process. The experimentally obtained data are set approximations of the relative deformation using ShrCeC. Subsequently the numerical simulation of shrinkage of selected silicate specimens using a computer applications SpatiDist and FyDiK 2D. The real test specimens are modelled as two-component composite consisting of cement paste and aggregates. The result is a parametric study takes into account the influence of type and size of grain aggregate.
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Analysis of fracture of quasibrittle materials using numerical modelling and acoustic/electromagnetic emission
Vodák, Ondřej ; Vořechovský, Miroslav (referee) ; Veselý, Václav (advisor)
This master thesis gives overview of non-destructive tests of concrete and provides detailed information concerning the acoustic and electromagnetic emission during monitoring of concrete failure. Conducted loading tests of plain concrete specimens are described in the thesis together with the performed numerical simulations of these tests in the software ATENA. The simulation results of concrete failure are analysed in detail and compared with the experimental results recording failure processes with the help of acoustic and electromagnetic emission. The majority of simulation results in software ATENA 3D show good agreement with the recorded data.
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Fractal capacitors properties
Chvíla, Ladislav ; Sedlák, Petr (referee) ; Hruška, Pavel (advisor)
This work is focused on computer simulations of fractal capacitors. The geometry of capacitors and its influence is investigated. Simulations are realized in programs Matlab, SolidWorks and Comsol Multiphysics. There are also several specific examples of different geometrics of capacitors their comparisons and assessment.
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Ostwald ripening – theoretical description and simulation.
Čechal, Tomáš ; Šikola, Tomáš (referee) ; Čechal, Jan (advisor)
Tato práce se zabývá popisem Ostwaldova zrání trojrozměrných ostrůvků deponovaných na rovinných površích. V první kapitole jsou představeny dvě teorie Ostwaldova zrání: LSW teorie založená na aproximaci středního pole a mnohačásticová teorie vycházející z řešení difuzní rovnice v kvazistatické aproximaci. Ve druhé kapitole je popsán algoritmus numerického řešení rovnic získaných z mnohačásticové teorie. Výsledky numerického řešení jsou ve třetí kapitole srovnány s předpověďmi LSW modelu. Bylo zjištěno, že předpovědi standardní LSW teorie popisující systémy s dvourozměrným transportem hmoty jsou v ostrém protikladu jak s výsledky získanými z dokonalejšího mnohačásticového modelu, tak s experimenty popsanými v uvedených pramenech. Mnohačásticový model založený na difuzní rovnici poskytuje výsledky konzistentní s jinými teoriemi i experimentem.
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Ventilation and air conditioning of a car cabine
Viščor, Petr ; Hejčík, Jiří (referee) ; Fišer, Jan (advisor)
In this work are described kinds and functions of air-conditioning systems which are used in cars. Further is described heat transfer between car cabin and ambient environment and issue of reduction of air-conditioning energy consumption. Last part of the work contains numerical simulation made by the THESEUS-FE 2.1 software package. This simulation was done on a model of the Toyota Prius car and was focused on effect of glazing on a temperature of the air inside the car cabin during hot summer days.
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Fracture process zone and energy dissipation during fracture of quassi-brittle materials
Klon, Jiří ; Seitl, Stanislav (referee) ; Veselý, Václav (advisor)
The work is focused on the comparison of selected fracture properties of quasi-brittle materials, particularly concrete, determined from results from tests on specimens of different sizes and notch lengths. The first part deals with the study of selected plasticity (failure) criteria and their testing within the mathematical package (MathCAD) for their later intended implementation in a program for estimation of the size and shape of the fracture process zone. Next part is devoted to numerical simulations of three-point bending test of notched beams. These simulations were performed using the ATENA FEM software. Results of the simulations are evaluated using fracture models; this thesis presents values of fracture parameters quantifying the amount of energy dissipated in the fracture process zone.
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Motion of the dynamic impact damper
Peterka, František
Properties of the tuned dynamic impact damper is studied by numerical simulation. Different regimes of the system response on the harmonic excitation is evaluated and regions of existence and stability are ascertained. Specified behaviour as grazing, period doubling, saddle-note and Hopf bifursations are explained.
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