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Study of the flood protection measures
Žiaková, Tereza ; Duchan, David (referee) ; Dráb, Aleš (advisor)
The bachelor thesis focuses on the assessment of the channel capacity and the design of flood protection measures on the Kotojekda river from the mouth to the Morava River up to river kilometre 3,200. The thesis includes hydraulic calculations using a 1D model. As a result, the proposed flood protection measure is in the form of raising the dikes to the design flow of Q20 with a safety elevation of 40 cm. This design, in combination with the previously developed dry reservoir design, provides protection of the area up to Q100 and protection of the surrounding area from flooding.
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Comparison of 1D and 3D Hydrodynamic Models in Designing a Hydraulic Object of a Dry Reservoir
Skokan, Jiří ; Dráb, Aleš ; Duchan, David
This article describes and compares computational and result differences in 1D and 3D hydrodynamic models, which are used for capacity assessment of flow control structures. The paper focuses on a considered dry retention reservoir located on the Kotojedka stream near the city of Kroměříž, Czech Republic. Based on project documentation, a detailed 1D steady hydrodynamic model using functions of Microsoft Excel and its native VBA language was created for the functional object. The parameters of the functional object were optimized based on the results of the 1D model. During the 1D analysis, some uncertainties occurred which cannot be addressed using standard or even more complex hydraulic analytical methods, such as formation and course of hydraulic jump, manifestation of overflow and bottom inlet submergence and water surface elevation profile in apron. Experimental physical model research was not undertaken in this case due to the high cost of the model relative to its lower significance compared to other, much larger water structures. Therefore a 3D steady hydrodynamic model could bring the required solution in this case and provide the basis for object parameters optimisation. A 3D model was created using Flow – 3D software. The results were compared on a series of QN flow rates from Q10 to Q10000, where QN represents the discharge with a repetition period of once in every N years.
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Study of flood protection measures in the Kroměříž locality
Skokan, Jiří ; Golík, Pavel (referee) ; Dráb, Aleš (advisor)
The diploma thesis deals with the design and hydraulic assessment of a dry retention reser-voir on the Kotojedka (IDVT 10202906) and Vážanský potok (IDVT 10189772) streams in Kroměříž. The basic designs of the dam parameters and the associated dry retention re-servoir flow control structure were carried out using hydraulic analytical calculations. A 1D hydrodynamic model was built by the author in the HEC-RAS software to assess the flow through this object. In the 1D analysis, some uncertainties could not be resolved, such as the formation and evolution of the hydraulic jump, the effect of the safety spillway and bottom outlet submergence, the capacity of the bottom outlet, the capacity of the apron and the water surface elevation in the apron. It can be assumed that, due to the lower significance of the proposed reservoir, it will not be subjected to research on the phy-sical model. Therefore, a hydraulic analysis with 3D numerical software comes into conside-ration, which in this case can provide results for the hydraulic design or optimisation of the desig-ned object parameters. Using the Flow - 3D hydrodynamic model, hydraulic calculations of water flow through the flow control object were performed. The results were compared with the values determined by the 1D model and analytical calculations. The results were compared in the selected profiles of the dry retention reservoir’s flow control object and the transformation effect of the reservoir.
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Mathematical Modeling of Heat and Mass Transfer in a Rotary Kiln
Kozakovič, M. ; Havlica, Jaromír ; Huchet, F.
The main objective of this research was to compare the results of the proposed 1D transport model with numerical simulations of mass transport in a direct-heat rotary kiln at laboratory scale. Another objective was to investigate the effect of the number of flights on the formation of an active particle surface in the airborne phase, which enables efficient heat transport. The studied rotary kiln is a low-angle cylinder with a length of 0.5 meter and a diameter of 0.108 meter with regularly arranged flights on the inside. The heat is transported into the rotary kiln by hot air at the inlet. The load in the rotary kiln consists of spherical particles with 1 millimeter diameter. The rotary kiln rotation speed is 21.5 rpm. For each simulation, 20 rotations were performed. The Discrete Element Method implemented in an open-source code LIGGGHTS was used for simulations.Efficient heat transfer is made possible primarily by the large number of particles in the airborne phase, which are heated by the warm air blowing in. To begin with, the number of flights and their geometry were found to be a key parameter controlling the amount of particles in the gaseous regime. It was also found that an area in the right part of the base of the cylinder is formed which is not reached by particles from the flights. This phenomenon is due to the dynamics of particle transport, as the particles are not maintained in the active phase and move rapidly towards the load due to gravity. In conclusion, the effect of this zone is negative, as hot air flows through it without resistance, preventing the system from heating effectively.
Plný tet:  PDF
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Termodynamická analýza procesů v palivových článcích s pevnými oxidy
Vágner, Petr ; Maršík, František (advisor) ; Némec, Tomáš (referee)
The fuel cells are the technology of the future. Although their discovery dates back to the 19th century the nature of how they work hasnt been adequately explained so far. This thesis focuses on description of solid oxides fuel cells (SOFC) for which ion conductive electrolyte and high operating temperature are distinctive. The mathematical model of SOFC developed in this thesis is formulated in terms of the mixture theory. The model development was constrained and simplified by isothermality, time-stationery and 1D approximation. The model equations characterize gas and ion transport and electric current flow in the fuel cell. Eventually comparison of the thesis model equations with the SOEC (solid oxides electrolysis cell) model developed at the Institute of Chemical Technology in Prague showed that both approaches lead to a similar conclusion. This thesis can be used as a basis for an experimental verification of the mixture theory. 1
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