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CFD modelling of pipe flow mixing of liquids
Pavlíček, David ; Hájek, Jiří (referee) ; Juřena, Tomáš (advisor)
This work is focused on computational modelling of mixing fluids in pipeline with static mixers. Main objective is to analyze several selected static mixers in a particular industrial application, namely dosing of the aluminium sulphate solution in the clarification process for potable water treatment. The analysis focuses on the degree of mixedness and pressure loss of individual mixers. Further, the aim of this work is to process the search of available types of static mixers. The benefit of this work is at least an effort to motivate the reader to deeper understanding of the mixing fluids, especially by static mixers.
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Experimental Analysis of the Liquid Breakup Process of an Effervescent Atomizer
Zaremba, Matouš ; Hyhlík, Tomáš (referee) ; Hájek, Jiří (referee) ; Jedelský, Jan (advisor)
The thesis deals with experimental research of mechanism of liquid breakup at twin-fluid atomizers. Four different atomizers were examined at the beginning of the research. Two of them were of standard design (Y-jet and effervescent nozzles), and the rest two atomizers were developed as a part of the thesis (so called CFT and inversed effervescent atomizers). Results show that only the inversed effervescent atomizer was capable of generating stable spray under examined conditions due to the specific breakup mechanism. This mechanism is similar to what was observed in effervescent atomizers. However, the mixing process inside the inversed effervescent atomizer is very different. The specific breakup mechanism was then defined as the main scope of the thesis. It was investigated by the high-speed imaging. The images were then processed by proper orthogonal decomposition and by fast Fourier transformation. Spray spatial development was examined using phase Doppler anemometer. The data was analyzed to describe the dynamics of the spray. A detailed description of the breakup mechanism is made from the combination of the experimental and post-processing techniques. The thesis brings new insight into the understanding of the liquid breakup mechanism and shows a potential for a further development of the inversed effervescent atomizer.
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Taxonomy of beetle families Eulichadidae and Callirhipidae (Coleoptera: Elateriformia)
Hájek, Jiří ; Král, David (advisor) ; Bezděk, Jan (referee) ; Löbl, Ivan (referee)
In my thesis I have focusedon the alpha-taxonomyof two poorly known beetlefamilies Eulichadidaeand Callirhipidae occurringpredominantlyin forestsof tropical areas.Both familiesareclassifiedas incertaesediswithintheseriesElateriformia. The smďl elateriformfamily Eulichadidaecomprisesof two extantgenera:the monoýpic Califomian genusStenocolusLeConte, 1853,andthepredominatelyOrientalgenusEulichas Jacobson,l9l3, with 42 describedspecies.The larvaeofboth geneÍaareaquatic,while the adultslive on vegetationneaÍwateÍ,and especiallythe genusEulichas is oftenattractedat light. Altogether182taxaatthespecieslevel belongingto six generaarecunentlyclassiftedin the family Callirhipidae.Membersof the family occurmainly in tropicsof Oriental,Australian andNeotropicalzoogeographicalregions.Larvaefeedon rottenwood,adultsarecollectedon deadtreetrunks,butmostofall theyareattractedatlight. REVISION OF THE GENUS EULICIIAS JACOBSON, 1913 (COLEOPTERA: EULICHADIDAE) I. INTRODUCTION, MORPHOLOGY OF ADULTS, KEY TO SUBGENERA AND SPECIES GROUPS. AND TAXONOMY OF E. FUNEBRIS SPECIES GROUP [ - seelist of publications] First partof the revisionsummarizesour knowledgeaboutthe genusEulichas. It containsa detailedmorphologyof adults,andkeys to identificationof subgeneraandspeciesgroupsof the genus.The taxonomyofthe E funebris speciesgroupis...
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Calcination model developement for ANSYS Fluent
Anderle, Milan ; Hájek, Jiří (referee) ; Vondál, Jiří (advisor)
The aim of the diploma thesis was creating a decarbonisation model of lime, implementation the model into CFD tool ANSYS Fluent and to test the decarbonisation model in a model of a real reactor. The required model was based on assumptions for a Shrinking Core Model (SCM). The main objective of this work was the non-catalytic conversion of substances and the search for the most used mathematical models for calcination. The CFD calculation, the sensitivity analysis and the Fluente parametric study were used. Data on the composition of gas flow, temperature, pressure and mass flow of limestone particles were selected for input variables. The particle model called Multiple Surface Reactions (MSR), which is a standard part of Fluent, was used at first. Subsequently, a UDF which was based on the SCM assumptions was written in the programming language C. The results of the CFD calculation were compared with the experimental values from the dissertation. It has been found that the MSR is sufficiently precise for calculation purposes but neglects the internal diffusion of CO2 through the CaO layer which forms behind the reaction front during calcination. It was found that it is possible to solve the flow with ongoing calcination without the need to know the parameters of the Arrhenian equation if the UDF is used. The created UDF incorporates the influence of intraparticular CO2 diffusion on the overall reaction rate.
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Application of Balanced Scorecard
Mrkvová, Klára ; Neumaierová, Inka (advisor) ; Hájek, Jiří (referee)
The objective of the Master´s Thesis is to apply the Balanced Scorecard system in a foundry company. The theoretical part defines the strategic management, it introduces individual parts of the Balanced Scorecard system and methods for its implementation in the company. The practical part use the methods listed above and applies them to the specific company An external analysis is applied to identify the relationship between the enterprise and its surroundings As a part of the internal analysis, financial indicators are calculated and compared with other enterprises in the sector. Based on the results of analyzes, the strengths as well as the weaknesses are identified and the strategy and strategic goals are set in four perspectives. To achieve these goals, the strategic map is created as the way of expressing and communicating strategy throughout the whole company. Moreover, the final section emphasizes the need for Balanced Scorecard integration into the company's management and management system.
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Ranking of selected tyre services
Zámorská, Kristýna ; Neumaierová, Inka (advisor) ; Hájek, Jiří (referee)
The purpose of this master thesis is to compare the company ContiTrade Services s.r.o. with its competitors between the years 2011 and 2014 by creating a ranking of selected tyre services. This thesis is divided into a practical section and a theoretical section. In the theoretical section are shown basic terms related to the intercompany comparison, the principles of the strategic tool Balanced Scorecard, the chosen indicators for the ranking and the methods of creating a rank within the intercompany comparison. In the practical section a spread (ROE - re), ROE, ROA, ROS, a turnover, a net profit, the amount of subsidiaries, the amount of services, an increase of tangible assets and labour costs are the basis for creating a ranking. These indicators are divided into four section according to the strategic tool Balanced Scorecard. There has been also created a complex ranking between the years 2011 and 2014 based on the above listed indicators.
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Business Model Analysis of the Company Aircraft Industries, a.s. and Suggestions for Improvement
Maturkanič, Michal ; Neumaierová, Inka (advisor) ; Hájek, Jiří (referee)
The graduation theses applies itself to business model analysis of the company Aircraft Industries, a.s. which run a business in production and sales of small civil aircrafts L-410. The company is struggling with period full of uncertainty which caused the fall of sales, fabrication restriction as well as loss in trading incomes. Unfortunately, according to some analysis performed in the diploma work, the current problems have not been caused just by contemporary events, though by long-term inappropriate set of processes in the firm, too. After all, the work shows possible development in the near future, its impact on the company, as well as suggestions which should be received and accepted by management to avoid any further negative impacts on the company.
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