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Electrohydrodynamic Model Of Electron Microscope
Mačák, Martin
This work presents a complex multiphysics model of an electron microscope in ANSYSFluent software. A custom electromagnetic model was used to describe the relativistic transport ofelectrons. The model consisted of a description of an electromagnetic field, relativistic transport ofcharged particles and interactions between charged particles and solid materials. Presented resultssuggest, that the custom model can be coupled with the CFD module, which results in a possibilityof coupled simultaneous simulations of hydrodynamics, electromagnetics, and a transport of chargedparticles.
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Analyses Of Static Pressure In Oblique Shockwave On The Probe Tip
Jenáček, Jakub
This article deals with the debugging analyses of Ansys Fluent for supersonic flowanalyzes. It is about analyzes on which the debugging of Ansys Fluent was made for analyzes ofsupersonic flow circumfluent the tip of the probe compared with the theory of isoentropic onedimensionalflow as a basic step for further analyzes in low pressures. The results shown in this paperwill further serve as a basis for experimental measuring of given problem.
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Numerical Modelling Of Li-S Chemistry
Mačák, Martin
This work presents a custom electrochemical model of a lithium-sulfur cell implemented into Ansys Fluent software. The model was used to analyse cyclic voltammetry at differently sized particles, which represented porous cathodes. The results indicate that the cyclic voltammetry response of the whole porous sulfur cathode could be solved as a response of a single particle, which might lead to a simplification of numerical simulations and in result, to accelerating their optimizing process.
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Specifics Of Static Pressure Measurement By Pitots Tube
Maxová, Anna
This paper deals with the analysis of the cone of the Pitot tube for sensing the static pressure in the supersonic flow in the experimental chamber. The probe requires a precise tip angle to eliminate a perpendicular shock wave. In our case, the angle tip was evaluated based on the results obtained by mathematical - physical analysis in the Ansys Fluent system. The results presented in this article will further serve as a basis for experimental problem measurement.
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Evaluation Of Continuity Of Environment Based On Knudsen Number Calculations
Jenáček, Jakub
This article deals with the evaluation of the Knudsen number in the research area of the Experimental Chamber. The number indicates the continuity of the environment. In our case, the Knudsen number was evaluated on the basis of results obtained by mathematical - physics analysis in the Ansys Fluent system. The results presented in this article will further serve as a basis for experimental measurement of the problem.
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Monitoring and Simulation of ADS Experimental Target Behaviour, Heat Generation, and Neutron Leakage
Svoboda, Josef ; Kliman,, Ján (oponent) ; Wagner,, Vladimír (oponent) ; Katovský, Karel (vedoucí práce)
Sub-critical Accelerator-Driven Systems (ADS) technology is able to deal spent nuclear fuel of present nuclear reactors, by using the transmutation technique of long-lived radioactive isotopes. As well, the ADS technology is solving the potential problem with the lack of U-235 by possible utilisation of U-238 or abundant Th-232. This doctoral thesis deals with research on the topic of spallation reaction and heat generation of various experimental targets in the frame of base ADS research. All thermal experiments, in total 13, have been performed at Joint Institute for Nuclear Research (JINR) in Dubna, Russian Federation, during the years 2015-2019. Various targets were irradiated as 512 kg of natural uranium target QUINTA, elongated cylindrical lead target and carbon target, or lead bricks target by 660 MeV protons at the irradiation facility Phasotron at JINR. A special experiment was performed with irradiation of two small uranium cylinders the QUINTA consist of. The author investigates the heat generation by proton reactions (inelastic scattering, and ionisation losses) which are part of spallation reaction including Coulomb scattering (or Rutherford scattering, which represents elastic scattering of charged particles); neutron reaction (mostly contributed by fission); pion reaction; and finally gamma heating, the heat generated by photon capturing. The temperature was experimentally measured by highly accurate and specially calibrated thermocouples. The temperature was measured on the surface, and also inside of the target. Additional research was aimed at neutron leakage monitoring T measurement of tiny volume probes by accurate thermocouples. The first probe contains a small amount of fissile material and the second one of non-fissile material with similar material characteristics. Leaking neutrons (neutron flux outside of the target) were detected due to direct heating by fission reactions. This work deals with accurate temperature measurement by thermocouples. It uses the LabView software for data acquisition, the National Instrument hardware for measuring, and Python 3.7. for data manipulation, analysing and visualisation (with employing several libraries). The particle transportation is simulated by MCNPX 2.7.0. and finally, the heat transfer and surface temperature estimation are simulated by ANSYS Fluent (or ANSYS Transient Thermal for simpler problems).
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CFD analysis of thermal stress of a tubesheet
Vince, Tomáš ; Babička Fialová, Dominika (oponent) ; Rebej, Miroslav (vedoucí práce)
This diploma thesis focuses on the phenomena of multiphase flow in a steam generator as a one of probable causes of tubes and tubesheet weld cracking. In the first part of the work, a research was carried out focusing on the boiling and the phenomenon of two-phase flow in technical applications, its characteristics and properties. The thesis continuous with an overview of available numerical multiphase models in the ANSYS Fluent 2021 R1 and a research of previously published works focused on two-phase flow with the presence of boiling. The research is followed by a description of the particular boiler, which is part of the nitric acid production plant in the chemical company DUSLO, a.s., its operating conditions and a more detailed description of the issue that is being addressed in this thesis. The second part of the work continuous with a description of the computational model, including a description of the geometry of the model and used simplifications, the computational mesh and the description of boundary conditions. Important part is the description of calculation setting of steady-state and transient CFD simulations in ANSYS Fluent. Finally, the results of the two-phase flow calculation are presented and then discussed in the conclusions.
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Vliv způsobu čerpání experimentální komory na průběh teploty plynu
Balobanov, Damir ; Bílek, Michal (oponent) ; Maxa, Jiří (vedoucí práce)
Diplomová práce se zabývá problematikou čerpání v experimentální komory elektronového mikroskopu na průběh teploty plynu. V teoretické části je popsána mikroskopie obecně. Poté se práce zabývá konkrétně elektronovou mikroskopií s problematikou jejího vakuového systému, výpočetními programy a studií, ze které práce vychází. V praktické části jsou provedeny a vyhodnoceny simulace čerpání v experimentální komoře pomocí systému Ansys Fluent.
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Návrh konstrukční úpravy sestavy sacího ejektoru pro medicínské použití
Boháč, Petr ; Štefan, David (oponent) ; Návrat, Tomáš (vedoucí práce)
Tato bakalářská práce se zabývá konstrukční úpravou dvoustupňového sacího ejektoru pro medicinální použití s pracovním názvem Medieject II. Navržené úpravy mají dosáhnout snížení hodnoty vytvořeného podtlaku oproti původní hodnotě a tím také umožnit přesnější regulaci vzniklého podtlaku. V první části práce jsou přiblíženy teoretické předpoklady, funkce a požadavky na vícestupňový sací ejektor, který má sloužit v lékařském prostředí. V druhé části práce je popsán analytický výpočet původní varianty, který slouží jako částečná kontrola následných numerických simulací. Třetí část práce se zabývá CFD simulacemi, které jsou využívány jako hlavní metoda pro řešení konstrukčních návrhů. Pomocí simulací proudění jsou navrženy dvě konstrukční úpravy a jejich několik dílčích variant. Následně jsou tyto úpravy podpořeny experimentem. Druhý návrh konstrukční úpravy, bude použit pro výrobu zařízení, které bude splňovat dané požadavky.
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