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Operating Data in TerraGear GIS Project
Samia, Michel ; Herout, Adam (referee) ; Hrubý, Martin (advisor)
This thesis is concerned with design and implementation of system for providing, loading and viewing geographical data from TerraGear GIS project with taking advance of SimGear library. System accesses digital terrain model and land cover data saved in Binary TerraGear file format via simple application protocol above TCP/IP and views it by FreeGLUT library.
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CFD modelling of granular flow in rotary kiln
Slowik, Roman ; Vondál, Jiří (referee) ; Juřena, Tomáš (advisor)
This work deals with modeling the flow of particulate matter in rotary kilns. For this purpose, a combined CFD and Discrete Element Method (DEM) model was used. Using Ansys Fluent software, several simulations were performed in order to determine the mean residence time and movement of the material in the rotary drum dryer. Results of the computational model were used to develop a regression model of the mean residence time and compared to the values as given by empirical equations. Furthermore, a simplified sensitivity analysis was performed for the selected input parameters of the model such as the stiffness constant, air mass flow rate and the particle size.
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Track's Elevation Profile View on a Public GIS
Doubal, Štěpán ; Šilhavá, Jana (referee) ; Fapšo, Michal (advisor)
This bachelor's thesis describes the design and implementation of a user script for GreaseMonkey (plug-in for Firefox). This script adds a functionality to show height profile of a defined route. The route is defined using public GIS tools from www.mapy.cz. The script extracts coordinates from page DOM structure, processes it and draws a height graph. The graph is created using http://www.heywhatsthat.com/profiler.html [2] or www.profile.hy.cz, which provides height graph drawing using www.vyskopis.cz JavaScript API [4].
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Improving computational efficiency of contact solution in fully resolved CFD-DEM simulations with arbitrarily-shaped solids
Studeník, Ondřej ; Kotouč Šourek, M. ; Isoz, Martin
The abundance of industrial processes containing both solid and liquid phases generate demand for fully resolved models allowing for detailed analysis and optimization of these processes. An established approach providing such models is based using a variant of an immersed boundary method to couple the computational fluid dynamics (CFD) and discrete element method (DEM). In the talk, we will present our custom and monolithic implementation of a fully-resolved CFDDEM solver and concentrate on the intricacies of solving contact between two arbitrarily-shaped solids. We shall propose an efficient contact treatment based on the concept of a virtual mesh, which provides the mesh resolution required by DEM through dividing the space around the contact point in a finite volume fashion without any changes to the CFD mesh itself. A substantial part of the talk will devoted to the parallelization of the contact solution, especially in the context of the domain decomposition method imposed by the CFD solver.
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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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Octree-generated virtual mesh for improved contact resolution in CFD-Dem coupling
Studeník, O. ; Kotouč Šourek, M. ; Isoz, Martin
The present work is focused on improving the efficiency of a computational fluid dynamics (CFD) – discrete element method (DEM) solver allowing for computations with non-spherical solids. In general, the combination of CFD and DEM allows for simulations of freely moving solid particles within a computational domain containing fluid. The standard approach of CFD-DEM solvers is to approximate solid bodies by spheres, the geometry of which can be fully defined via its radius and center position. Consequently, the standard DEM contact models are based on an overlap depth between particles, which can be easily evaluated for a sphere-sphere contact. However, for a contact between two non-spherical particles, the overlap depth cannot be used and has to be replaced by the more general overlap volume. The precision of the overlap volume computation is (i) crucial for the correct evaluation of contact forces, and (ii) directly dependent on the computational mesh resolution. Still, the contact volume evaluation in DEM for arbitrarily shaped bodies is usually by at least one order of magnitude more demanding on the mesh resolution than the CFD. In order to improve the computational efficiency of our CFD-DEM solver, we introduce the concept of an OCTREEbased virtual mesh, in which the DEM spatial discretization is adaptively refined while the CFD mesh remains unchanged.
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Recent improvements in CFD solver for fully coupled particle-laden flows
Šourek, M. ; Isoz, Martin
While new methods combining the computational fluid dynamics (CFD) and the discrete element method (DEM) have been developed to simulate freely moving solid particles, they tend to be focused on simulations with spherical particles only. Here, we present a strongly coupled CFD-DEM solver capable of simulating movement of arbitrarily-shaped particles dispersed in a fluid. The particles are assumed to be large enough to affect the fluid flow and distributed densely enough to come into contact with both the boundaries of the computational domain and with each other. In this paper, we will focus on the recent improvements of our solver, specifically, in the areas of (i) inclusion of solid bodies into the computational domain, (ii) general CFD-DEM coupling algorithm, and (iii) code parallelization and practical usability.
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Fotogrammetric analyses of aerial pictures of mountain landscape and generation of DEM
Hynštová, Marie ; Stuchlík, Evžen (advisor) ; Matějíček, Luboš (referee)
This thesis describes the stereo photogrammetric method used for digitalization of terrain elevation data of choosen area and the applications of digital elevation model (DEM). The main part of the thesis consists of DEM generation methodology, including stereo photogrammetric evaluation of aerial pictures, quality control of evaluating process, DEM creation and revision. DEM was created in software Edras Imagine 8.6. The thesis results in detailed description of DEM creation in the high mountain terrain selected in the High Tatra Mountains. Grid DEM of cell size 1x1 meter is attached. Key words: mountain lakes and catchments, photogrammetry, aerial pictures, DEM
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CFD modelling of granular flow in rotary kiln
Slowik, Roman ; Vondál, Jiří (referee) ; Juřena, Tomáš (advisor)
This work deals with modeling the flow of particulate matter in rotary kilns. For this purpose, a combined CFD and Discrete Element Method (DEM) model was used. Using Ansys Fluent software, several simulations were performed in order to determine the mean residence time and movement of the material in the rotary drum dryer. Results of the computational model were used to develop a regression model of the mean residence time and compared to the values as given by empirical equations. Furthermore, a simplified sensitivity analysis was performed for the selected input parameters of the model such as the stiffness constant, air mass flow rate and the particle size.
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