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Modern technological elements for tubular heat exchangers
Plánková, Tereza ; Babička Fialová, Dominika (referee) ; Jegla, Zdeněk (advisor)
The aim of this diploma thesis is to get acquainted with modern technological elements currently used in shell-and-tube heat exchanger in the shell-side and tube-side, thermal-hydraulic calculation of selected elements and comparison of thermal-hydraulic properties with classically used competing technological elements. The work deals mainly with EM baffle in the tube-side and tube inserts like the twisted tape type (and its modifications) and coiled wire in the tube-side. The theoretical part is focused on acquaintance with classical technological elements in shell-and-tube heat exchanger and with basic thermal-hydraulic calculations, practical part then on acquaintance with modern elements and thermal-hydraulic calculation of selected elements. These calculations are then compared with the results of the thermo-hydraulic calculation of similar elements.
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Application of Polymeric Hollow-Fiber Membranes in Air Filtration
Bulejko, Pavel ; Dohnal, Mirko (referee) ; Friess, Karel (referee) ; Svěrák, Tomáš (advisor)
Membrány z dutých vláken jsou široce využívány v aplikacích týkajících se úpravy kapalin jako např. při čištění odpadních vod, v membránových kontaktorech a bioreaktorech, membránové destilaci apod. I když jsou často využívány při separacích směsí plynů, je jejich použití pro mechanickou filtraci aerosolů velmi vzácné. Tato práce se zabývá filtrací vzduchu pomocí polypropylenových membrán z dutých vláken včetně jejich filtrační účinnosti, tlakových ztrát a také zanášením při dlouhodobé filtraci. Filtrační účinnost byla proměřena za použití různých aerosolů jako TiO2 a síran amonný. Tlakové ztráty byly měřeny při různých konfiguracích, tj. různé filtrační ploše a průměru vlákna membrány. Zanášení membrán bylo testováno použitím normovaného prachu definovaného normou ANSI/ASHRAE 52.2. Predikční modely pro filtrační účinnost a permeabilitu/tlakovou ztrátu membrány byly aplikovány na parametry membrán z dutých vláken a porovnány. Tyto membrány mají velikost pórů kolem 90 nm a poměrně nízkou porositu a tím vysoký potenciál pro separaci nanočástic ze vzduchu. Dále byla provedena analýza filtračního koláče a vyhodnocení energetických nároků a porovnány s teoretickými modely. V závěru práce je nastíněn odhad ceny životního cyklu při filtraci pomocí těchto membrán.
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Heat recovery from melting furnace waste gases
Dobai, Szabolcs ; Hejčík, Jiří (referee) ; Jaroš, Michal (advisor)
This master’s thesis deals with the design of heat recovery system from melting furnace waste gases. The first part is devoted to a brief description of heat exchangers, with the special importance being placed on the shell-and-tube heat exchanger. The second part contains a calculation of stoichiometric combustion, design of geometrical dimensions, calculation of pressure drops and power. At the end of the thesis there are various possibilities of utilization of the obtained waste heat and their basic economic assessment.
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Air filtration
Krajčová, Kateřina ; Uher, Pavel (referee) ; Rubinová, Olga (advisor)
The diploma thesis describes the design of air conditioning equipment of materni-ty hospital and experimental measurement nanofilters and their subsequent comparison with conventional air filters. The work consists of three parts. The first part describes the types of filters. Nanofilters and nanofiber materials are de-scribed in detail here. In the second part is the topic of air filtration applied to the maternity hospital. Two variants of air conditioning and cooling are designed for the 3rd floor of this building. The third experimental part deals with antibacterial effects of thr silver fiber nanofilter and its comparison with commonly used filters. It also deals with the pressure drop on the filters at different air speeds.
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DEM-CFD study of flow in a random packed bed
Šourek, M. ; Isoz, Martin
Most catalytic surface reactions as well as other industrial applications take advantage of fixed packed bed reactors. Designers of these reactors rely mostly on empirical formulas derived for various simplifying assumptions, e.g. uniformly distributed porosity. The made simplifications and especially the assumption of uniformly distributed porosity fail if the tube to particle diameter ratio goes under 10 and the „wall effect“ becomes more significant. In such a case, the complete three-dimensional structure of the packed bed has to be considered. Thanks to ongoing improvements in numerical mathematics and computational power, the methods of computational fluid dynamics (CFD) have become a great tool for comprehensive description of the packed beds with low tube to particle diameter ratio. Three-dimensional simulations of the flow through two fixed beds differing in the type of the used particle are presented and compared with available experimental and empirical results. To generate the random fixed beds, we propose a custom approach based on the discrete element method (DEM) code implemented in open-source software Blender. Thereafter, OpenFOAM tools (snappyHexMesh, simpleFoam) are used for creation of the computational mesh and solution of the governing equations describing a single-phase flow in the packed bed.
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Calculation of pressure losses of flue gas ducts using mathematical modeling
Suchý, Václav ; Skála, Zdeněk (referee) ; Pospíšil, Jiří (advisor)
This diploma thesis deals with the calculation of pressure losses in the flue gas ducts. First part of this work describes properties of flue gas and flow dynamics. Part of the theoretical analysis was detailed study of pipeline elements with emphasis on the reasons for the existence of pressure loss in the flow, calculations of the resistance coefficients and possible methods of reducing the losses. In the practical part, a model of the pressure loss calculation of the existing flue gas line installed in the incineration plant was created. At the end of the thesis a proposal for optimization of this route was made with emphasis on the reduction of the overall pressure loss. By optimization the pressure drop of the specified route was reduced from 3581 Pa to 2647 Pa, i.e by 26% and the required power input of the fan was reduced from 225 kW to 166,5 kW.
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Air conditioning in the library
Pospíšilová, Lucie ; Uher, Pavel (referee) ; Blasinski, Petr (advisor)
Dissertation offers a plan for air – conditioning equipment of library building in Brno and it involves air filter experimental measurement. The proposal is divided into three parts. The first part explains air filter theory with detailed description of atmospheric air filters for separation of particles for general ventilation - filter parameter determination. Theory part ends specifically with pocket air filters and their construction. The second part focuses on experimental pocket air filter measurement execution, which calculates with variable filter cartridges and pocket count. Measurement also evaluates pressure drop and their efficiency. The last part of the dissertation looks at air – conditioning equipment design for specified building, concretely library building. The project solves fresh air traffic into interior of selected library rooms and it counts with thermal heat gain in summer season, heat loss in winter season and air humidity modification.
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Properties of ceramics foam filters needed for numerical simulation software
Boček, Vítězslav ; Láník, Boris (referee) ; Záděra, Antonín (advisor)
Final thesis, elaborated within the master study field of Foundry technology, deals with determination of some parameters of ceramic foam filters that are necessary for using numerical simulation during foundry practice. Thesis foccuses on defining methodology, manufacturing messuring device and measuring pressure drop on several type sof ceramic foam filters in dependence on flow rate of measuring medium. Measuring medium selected is water, mening this thesis deals also with water simulation in foundry technology.
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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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Space heating of a mixed-use building
Dvořák, Jakub ; Hejčík, Jiří (referee) ; Charvát, Pavel (advisor)
The subject of this diploma thesis is to design space heating system for building with five floors, where the first above ground floor is used as commercial space. Designed building have one underground floor and four above ground floors. Diploma thesis is designed as project of Building Service, specifically that of Heating. This diploma thesis contains calculations of the design heat load, design of radiators and others heating surfaces, hydraulic balancing, generation of domestic hot water, design of heat source, calculations of safety devices and pumps design. Part of this diploma thesis is also conceptual design of regulation.
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