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Fluid Flow in Nonstandard Process and Power Equipment
Chýlek, Martin ; Babička Fialová, Dominika (referee) ; Turek, Vojtěch (advisor)
Flow distribution has big importance in equipment with limited tube rows because it provides correct operation and sometimes specific flow distribution for technology purposes is needed. This thesis is focusing on flow analysis in these units using computational fluid dynamics (CFD). For analysis of such systems models with varying tube rows and varying perforated segment lengths were created. Analysis showed significant impact of flow manifold layout along with tube layout and number of tubes. Simplified 1D model using static pressure regain coefficient was created which provides much shorter computational times. Comparison of 1D and CFD models was made to determine field of their usage.
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Nautiloidea of Upper Cretaceous epicontinental seas in Europe
Frank, Jiří ; Košťák, Martin (advisor) ; Turek, Vojtěch (referee) ; Schlögl, Ján (referee)
The post-Triassic Nautiloidea are not as popular theme within fossils cephalopods research as for example ammonites. They are not very abundant in the fossil records except some rare localities and areas, their morphology is quite conservative and due to the usually poor preservation, their determination and assigning to the species even to genera level is often complicated. Exceptional are taxa with very specific morphology and short stratigraphic and endemic occurrence, which are even suitable for biostratigraphic interpretations. Problematic is also the often poor taxonomical representation of the type material and revision of many taxa is needed. Still nautilids are often represented by reasonable amount in the paleontological collections of natural history museums due to the long history of fossils collecting. Also the scientific literature has been dedicating at least some space to this group since 19 century. The aim of this study is to create an overview about the post- Triassic, especially Upper Cretaceous nautiolidea in the European region of epicontinental seas and prepare a good basement for extensive study of this group. Due to this aim the study is primarily focused on determination of morphological features and also problematic with their interpretation according to the variable...
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Selected bivalves from the Ordovician of the Prague Basin
Polechová, Marika ; Kraft, Petr (advisor) ; Turek, Vojtěch (referee) ; Mergl, Michal (referee)
Univerzita Karlova v Praze, Přírodovědecká fakulta Ústav Geologie a Paleontologie Charles University in Prague, Faculty of Science Institute of Geology and Palaeontology Doktorský studijní program: Geologie Ph.D. study program: Geology Autoreferát disertační práce Summary of the Ph.D. Thesis Vybraní mlži z ordoviku pražské pánve Selected bivalves from the Ordovician of the Prague Basin Mgr. Marika Polechová Školitelé / Supervisors: doc. RNDr. Petr Kraft CSc., RNDr. Jiří Kříž CSc. Praha, 1. 4. 2013 1 Abstrakt Cílem této disertační práce je revize vybraných ordovických mlžů z pražské pánve. Ordovičtí mlži patřili dlouhodobě k opomíjené skupině paleozoických bezobratlých. Úvodní část disertační práce se skládá z pěti kapitol, ve kterých jsou popsány hlavní charakteristiky mlžů, dále jsou podrobně popsáni ordovičtí mlži s důrazem na jejich systematiku, diverzifikaci, paleobiogeografii a paleoekologii. Těžištěm práce je revize mlžů ze šáreckého a kosovského souvrství pražské pánve. Zvláštní pozornost je věnována evolučně důležitým skupinám Protobranchia Pelseneer, 1889 a Actinodontida Dechaseaux, 1952. Všechny kapitoly jsou doplněny o nejnovější poznatky, které byly publikovány v šesti článcích zaměřených zejména na systematiku, paleobiogeografii, paleoekologii, diverzifikaci a ranou evoluci vybraných...
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Flow Distribution in Equipment with Dense Tube Bundles
Babička Fialová, Dominika ; Jegla, Zdeněk (referee) ; Turek, Vojtěch (advisor)
Significant maldistribution negatively influences performance of equipment containing dense tube bundles and, moreover, it can cause a wide range of operating issues. This thesis therefore focuses on analysis of fluid flow in complete distribution systems via computational fluid dynamics (CFD). Data obtained from simulations carried out using the software ANSYS Fluent were also statistically analysed. Influence of system arrangement, tube bundle parameters and operating parameters on flow distribution non-uniformity and pressure drop was investigated. According to the results, system arrangement is the crucial differentiating parameter in terms of flow distribution as well as pressure drop. Additionally, data obtained via the classical CFD approach were compared with those yielded by a simplified CFD model for three selected distribution systems. Simplified CFD approach can - given its low computational demand - be utilised in optimization algorithms as well as in the course of the initial stage of equipment design process. Furthermore, this thesis discusses a simulation tool which is based on the simplified CFD approach. Although this tool is still being developed, the results it yields are very promising.
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Application of process system engeneering
Hrncsjarová, Hana ; Turek, Vojtěch (referee) ; Jegla, Zdeněk (advisor)
The master’s thesis is focused on familiarization with modern techniques and procedures of process system engineering for identification of energy savings. In this case, process system engineering is applied to the issue of heat exchanger networks and in order to save energy, their retrofit is solved here. The current network pinch method, which uses mathematical programming options, is described for the retrofit of the heat exchanger networks. The method is presented in comparison to older development methods, mainly with the PDM. In addition, the calculation procedure is also developed by this method and in the Maple software environment it is applied to the case of heat exchanger network retrofit in the process of hydrogenation refining of oil. Part of the thesis is an evaluation of the results obtained, including a discussion of the properties of the method used.
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Taxonomic position of the species Bactroceras sandbergeri (Barr.,1867) from the Czech Ordovician
Aubrechtová, Martina ; Marek, Jaroslav (advisor) ; Turek, Vojtěch (referee)
Taxonomic position of the cephalopod Bactroceras sandbergeri (Barr., 1867) from the Ordovician of the Prague Basin was subjected to wide discussions and disputes in the past. The species was first classified within the genus Bactrites. Later, a separate, monotypic genus Eobactrites was defined. At present, the species is assigned to the genus Bactroceras. It belongs to the family Baltoceratidae, the genera of which are supposed to represent the oldest orthoceridans. The order Orthocerida is one of the most successful and most diversified cephalopod groups of the Paleozoic Era. In this thesis, a revision of Bactroceras sandbergeri has been made after a detailed study of about one hundred specimens. Attention was paid to those features, that are missing in the original species descriptions or that were neglected in the past. Special attention was paid mainly to muscle scars, structure of the siphuncle and morphology of the embryonic shell. The embryonic shell was originally described as Tretoceras parvulum Barrande, 1868. In addition, Orthoceras naufragum Barrande, 1870 was synonymized with the studied species and the species Orthoceras interpolatum Barrande, 1870 was assigned to the genus Bactroceras. Key words: Cephalopoda, Ordovician, Czech Republic, Barrandian area
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New Elements of Heat Transfer Efficiency Improvement in Systems and Units
Turek, Vojtěch ; Klemeš,, Jiří (referee) ; Odstrčil, Miloslav (referee) ; Jegla, Zdeněk (advisor)
Zvýšení efektivity výměny tepla vede k poklesu spotřeby energie, což se následně projeví sníženými provozními náklady, poklesem produkce emisí a potažmo také snížením dopadu na životní prostředí. Běžné způsoby zefektivňování přenosu tepla jako např. přidání žeber či vestaveb do trubek ovšem nemusí být vždy vhodné nebo proveditelné -- zvláště při rekuperaci tepla z proudů s vysokou zanášivostí. Jelikož intenzita přestupu tepla závisí i na charakteru proudění, distribuci toku a zanášení, které lze všechny výrazně ovlivnit tvarem jednotlivých součástí distribučního systému, bylo sestaveno několik zjednodušených modelů pro rychlou a dostatečně přesnou predikci distribuce a také aplikace pro tvarovou optimalizaci distribučních systémů využívající právě tyto modely. Přesnost jednoho z modelů byla dále zvýšena pomocí dat získaných analýzou 282 distribučních systémů v softwaru ANSYS FLUENT. Vytvořené aplikace pak lze využít během návrhu zařízení na výměnu tepla ke zvýšení jejich výkonu a spolehlivosti.
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Optimization of cogeneration system
Stacha, Radek ; Turek, Vojtěch (referee) ; Jegla, Zdeněk (advisor)
Master thesis is focused on optimization of cogeneration system for purpose of rating optimization methods and evaluating properties of these methods. For each method there is description together with block schemes. First part of thesis is devoted to description of methods and their comparison. Second part consists of development of hybrid algorithm, which is used to optimize cogeneration systém model. Each algorithm compared is together with hybrid algorithms included in annexes.
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