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Adjoint solver
Heinz, Pavel ; Kůrečka, Jan (referee) ; Moravec, Prokop (advisor)
This bachelor thesis deals with an analysis of selected settings of Adjoint solver in commercial software ANSYS Fluent 18.2. The first part of the thesis deals with the basics of hydrodynamics, especially the equations describing the behaviour of liquids. It also deals with the theoretical foundations of CFD simulation and shape optimization. Examples of simple shape optimization cases are presented in this thesis. The last part focuses on the analysis of selected settings of Adjoint solver. These settings are afterwards tested on specific hydraulic part for a purpose of a pressure loss reduction.
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Hydraulic retarder
Ryšková, Marie ; Stareček, Jakub (referee) ; Klas, Roman (advisor)
This thesis is devoted to the design of hydraulic retarder, with emphasis on CFD simulation. The thesis is based on simulation of flow in hydraulic retarder with included transformation of heat. The generation of heat at breaking with hydraulic retarder significantly influences amount of created moment. With use of simulations the anticipated breaking moment emerging on break of a spinning wheel from the design is verified. A group of brake models, in which the hydraulic break belongs to, is introduced in the beginning chapters. This following chapter focuses on design of simulation model that corresponds with the process of breaking. Simple 1D mathematical model for filling the brake with oil using compressed air is introduced.
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Study of the flow of immiscible liquids
Malá, Kateřina ; Pochylý, František (referee) ; Fialová, Simona (advisor)
This thesis explores the topic of flow of two immiscible liquids in horizontal pipeline. For this purpose, the experimental apparatus has been set up, that allows to observe the flow of mixture through the transparent pipe. Moderately viscous oil and water (viscosity ratio: 52,81, density ratio: 0.86, interfacial tension: 41,64 mN/m) have been chosen for the experiment. Both fluids were introduced into the pipe through a T-junction. At the end of the apparatus, a mixture of liquids flowed into the separation tank, where both phases were separated. The separated oil was then reused for further measurements. The oil and water flow rates could be individually changed by use control valves, that led to identification of different flow regimes. These varied from stratified flows to fully dispersed ones as the mixture speed increased. All observed flow regimes were plotted in the flow map, that is a function of the inlet velocities of both fluids. For further analysis, a second type of flow map has been created that displays rates as a function of mixture velocity and phase volume fraction. Selected regime was also simulated using software ANSYS FLUENT. The VOF method was used to simulate multiphase flow. This thesis critically evaluates the results of the study and shows the direction for further research in the field of immiscible liquids flow.
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Flow of combustion air in the burner of a rotary kiln
Dorniak, Michal ; Martykán, Jiří (referee) ; Vondál, Jiří (advisor)
Predložená diplomová práca sa vo svojej väčšej časti zaoberá CFD simuláciami. Cieľom tejto práce bolo komplexne zmapovať správanie sa prúdenia spaľovacieho vzduchu v horáku rotačenej pece a jeho bezprostredne nadväzujúcej oblasti. Celý proces vypracovania tejto diplomovej práce prebiehal v spolupráci s cementárňou Českomoravský cement, a.s., lokácia Mokrá, ktorá slúžila ako primárny zdroj údajov a validácie výsledkov. Každá CFD simulácia potrebuje pre jej úspešné overenie porovnanie s experimentálnymi dátami, čo sa nám základe spolupráce podarilo splniť. V úvodných častiach práce bol popísaný proces výroby cementu a používaná technológia práve v cementárni Českomoravský cement, a.s., prevádzka Mokrá. Následne boli popísané základné teoretické a výpočtové princípy CFD analýz s doplnením popisu doležitých parametrov potrebných na posúdenie výsledkov. Kontkrétna príprava na simuláciu prebiehala najskôr prvotným meraním skutočného horáku rotačnej pece priamo v cementárni. Takéto merania sa uskutočnili dve, pretože cementáreň disponuje dvomi rôznymi pecnými linkami. Používané horáky v jednotlivých linkách sa trochu odlišujú vo svojej najpodstatnejšej časti, v špičke horáku. Cieľ práce bol zamerať sa na horák s modernejším usporiadaním pre maximalizáciu prínosu zistení do budúcnosti. Prvé meranie sa uskutočnilo na horáku so staršou konfiguráciou, pretože pre nás podstatný, modernejší horák bol v tej dobe stále v prevádzke. Na základe prvého merania spolu s dostupnou a vzhľadom na vek neúplnovou výkresovou dokumentáciou, bol vytvorený model pomocou programu SolidWorks. Po neskoršom druhom meraní bol tento model prakticky overený a následne upravený, aby odpovedal modernejšej verzii horáku. Skúsenými inžinieromi zvalidovaný model, slúžil ako základ pre následujúcu prípravu celej simulácie. Príprava simulácie pozostávala z tvorby optimálnej siete, ktorá tvorila približne 60 % náročnosti úspešného vykonania analýzy a vhodným nastavením použitých výpočtových metód. Vykonané simulácie boli zamerané na dva väčšie ciele. Najkôr bolo vyhodnodnotené správanie spaľovacieho vzduchu v horáku a tesne za ním. Odhalené nedostatky boli s cementárňou prediskutované a boli navrhnuté možné riešenia problému. Druhým cieľom bolo vyhodnotenie erózneho poškodenia uhoľného kanálu. Poškodenie uhoľného kanálu bol odpozorované pri pravidelných údržbách horáku. Pre všetky zistené nedostatky boli navrhnuté možnosti, kde by sa práca mohla do budúcnosti pokračovať. Pre prípad spaľovacieho vzduchu bol optimalizovaný stav aj simulovaný.
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Calculation of the aerodynamic characteristics of the SIGMA sports car
Brychta, Ondřej ; Čavoj, Ondřej (referee) ; Vančura, Jan (advisor)
This thesis deals with the problem of disturbing forces that act on the crew of the SIGMA vehicle, especially in the area of the driver's head and houlders due to air flow. In the practical part, a model for CFD simulations is designed, a general characteristic of the car's aerodynamics is created and a comparison of the base variant of the car with variants with aerodynamic shields, which eliminate this uncomfortable phenomenon without worsening the aerodynamic resistance of the vehicle.
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Effect of light on microalgae growth
Adamec, Matěj ; Sukačová, Kateřina (referee) ; Naď, Martin (advisor)
Light is one of the key elements affecting the growth of photoautotrophic algae in photobioreactors. For optimal cultivation in such a device, sufficient access to light radiation to the microalgae is required sufficient light intensity is needed. In this work, considerable attention is paid to the influence of light during the whole photosynthesis process. Viable solutions for the illumination of the photobioreactor by natural and artificial light are evaluated in detail, including a description of its main parameters. The design of a programmable illumination for a newly designed photobioreactor with eight horizontal tubes and a control calculation of PPFD (Photosynthetic Photon Flux Density) were performed. Afterwards, the designed illumination was implemented on the newly built photobioreactor to evaluate the effect of photoperiod length and LED light coloration on the actual microalgae cultivation. Based on these data, the optimal photoperiod length could be determined, and ratios of 12:12, 18:6, and 24:0 (light phase:dark phase) were tested. Finally, to evaluate the spatial distribution of the photobioreactor illumination, CFD simulations of selected photobioreactor tubes were performed using simulation software ANSYS FLUENT.
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Optimization of hydrostatic bearing pad geometry using CFD simulation
Dryml, Tomáš ; Vimmr, Jan (referee) ; Michalec, Michal (advisor)
The master's thesis deals with the optimization of hydrostatic bearing pad geometry using CFD simulation and experimental measurements. By combining experimental and numerical approaches, the effect of variation of hydrostatic bearing recess shape and depth on individual operating parameters is investigated. The effect of geometry variations is determined by numerical simulations which have been validated with experimentally obtained data. The results show that the ideal recess depth should correspond to 20-50 times the lubrication layer height The simulations also show that depth variation has a significant effect on the operating parameters. In contrast, the variation of the recess shape does not significantly affect the operating parameters of the bearing. The design of the optimum geometry of the hydrostatic bearing is particularly important because it can bring significant financial and energy savings associated with the operation of (especially large-sized) hydrostatic bearings.
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Race car bonnet shape design based on flow analysis
Šnajdr, Petr ; Kvarda, Daniel (referee) ; Michalec, Michal (advisor)
The bachelor’s thesis deals with reducing aerodynamic drag of a pneumobile. The thesis summarizes knowledge in the field of vehicle aerodynamics and the principle of CFD simulations. The essence of the work is bonnet shape design of racing pneumobile Typhoon, developed at FME BUT, for lowest possible air resistance. CFD simulations are used to observe and analyse the influence of the bonnet shape on the aerodynamics properties. The designed shape solution of the bonnet significantly contributes to the reduction of aerodynamic drag compared to the existing bonnet. Thanks to this, the vehicle’s parameters are improved from maximum speed to the range. The acquired knowledge can also help in the further development of pneumobiles and in improving the setting of the computational model described in the work.
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Design and testing of a new drilling tool with inner channels
Havlíková, Hana ; Chladil, Josef (referee) ; Píška, Miroslav (advisor)
Tento projekt se zabývá optimalizací chladicích kanálků nového vrtáku navrženého společností SECO Tools pro obrábění titanové slitiny Ti-6Al-4V. Cílem tohoto projektu je optimalizovat průměr a polohu chladicích kanálků na hřbetu tak, aby se snížila teplota vrtáku a tím i životnost nástroje. Nový vrták je použit pro provedení vrtacích zkoušek s použitím konvenční řezné kapaliny (emulze s 7% koncentrací) při tlaku 40 barů. Získané výsledky jsou porovnány s výsledky získanými pomocí dostupného standardního vrtáku od společnosti SECO Tools pro vrtání obrobku Ti-6Al-4V. Teplotní CFD model je vytvořen pro různé hodnoty vstupních tlaků kapaliny pomocí turbulentího modelu k- SST a tepelného zatížení vypočítaného na základě vrtacích zkoušek. Výsledky pro standardní a prototypové vrtáky jsou navzájem porovnávány, s ohledem na průtok, teplotu vrtáku, rychlost kapaliny a přenos tepla do MWF. Následně je model použit k ověření optimalizovaných návrhů.
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