|
Mining and access shaft of the pilot adit with extended launch chamber
Kuhajdik, Adam ; Horák, Vlastimil (referee) ; Horák, Vladislav (advisor)
The diploma thesis deals with the design of a mining and access shaft with an extended launch chamber for the Vinohrady exploration adit in Brno. The requirements to be met by this underground work are defined. Based on an analysis of the applicable shaft sinking methods, two implementation procedures have been proposed. The combination of a drilled pile wall with extensive use of jet grouting appears to be preferable. This procedure is further elaborated in 2D and 3D models with static design assessment of the different structural parts and phases. The work further discusses displacements in the modelled environment and displacements on the structure. The static design of the shaft is complemented by a safety analysis of the embryo face of the exploration adit. A bill of quantities of the selected technical solution is also included in this work. The work with numerical models includes a comparison of the results of 2D and 3D models.
|
|
Numerical Modelling of Counter Flow in T-Junction
Míčka, Martin ; Šperka, Oldřich (referee) ; Štigler, Jaroslav (advisor)
The main objective of this master thesis is to implement the numerical modelling of the confluence of streams in the Tee-junction using Fluent CFD software. Modelling is carried out for different ratios of flow rates in steady flow. Calculations are evaluated, using a new mathematical model, by curves of loss coefficients. Furthermore, the influence of the selected type of the mesh in geometry on results from numerical modelling of flow is examined. Geometry of the Tee-junction is created in Gambit software. Finally, the results obtained from numerical modelling are confronted with results from an experiment.
|
|
Numerical model of aerosol formation during biomass combustion
Chýlek, Radomír ; Lízal, František (referee) ; Masaryk, Michal (referee) ; Pospíšil, Jiří (advisor)
This thesis focuses on creating a numerical model to describe the thermal impact on biomass with aerosol formation. The model is based on the modification of the network-based CPD model and is intended for simulating the thermal decomposition of biomass. The objective of this work was to verify the functionality of the model and perform comprehensive validation through laboratory measurements. The validation involved analyzing lignocellulosic biomass and its individual structural materials. The validation results confirmed the model’s ability to simulate slow pyrolysis with good agreement with experimental data. Prior research focused on determining the composition of biomass and selecting an appropriate model for biomass combustion/pyrolysis simulation. The thesis also describes other tested approaches and improvements to the CPD model.
|
|
Heat dissipation axially-cooled glassmaking
Hovorka, Martin ; Pospíšil, Jiří (referee) ; Baláš, Marek (advisor)
The presented thesis deals with a numerical simulation of axially cooled glassmaking parison. Several types of cooling channels have been investigated according to its usage in glassmaking process. Software Star CCM+ was used to describe properties throughout the channels and also the parison itself. The main focus of this thesis lies in comparing of temperature fields, cooling effects and cooling intensity among the chosen channel designs. The boundary condi-tions were kept the same accordingly to glassmaking conditions for every design. Some out-puts were transferred to non-dimensional diagrams in order to recalculation pursuant to other boundary conditions. Properties of diffuser channel designs were compared to an experiment. Transient temperature field of the parison were calculated with Ansys APDL in order to de-termine the accumulation and stationary zone of the parison and to verify the boundary conditions for cooling channels.
|
|
Vortex tube
Chýlek, Radomír ; Škorpík, Jiří (referee) ; Pospíšil, Jiří (advisor)
The purpose of this diploma thesis was to find optimal operational parameters of Ranque–Hilsch vortex tube that would give the best results of temperature separation, and to create a numerical model of the device. Firstly, extensive research of current literature was done and analytical model of the tube was created. Then, the numerical model of the vortex tube was designed using Star-CCM+ software. Afterward, best fitting turbulence model was chosen to do the calculation and optimal geometrical parameters of the tube were obtained as a result of CFD simulation. Then, inlet nozzles for the tube were designed and manufactured. Experimental evaluation of the vortex tube and description of its optimal settings form a substantial part of the project. Finally, the data obtained from the experiment were compared to the results of numerical analysis and conclusions were deduced.
|
|
Numerical modeling of the prestress hollow core slabs Spiroll type on the flexural support and the evaluation of the stresses
Kršík, Jakub ; Vejvoda,, Stanislav (referee) ; Kaplan,, Věroslav (referee) ; Křiváková, Jarmila (advisor)
The doctoral thesis describes the possibilities of numerical modelling of hollow core concrete panels, SPIROLL type. The commercial finite element program ANSYS 13.0 is used for the modelling. The focus is on the specific flexural support of the panel and on the distribution of the shear stresses in the panel ribs near the support. The goal is to valid actually used method for homogenization of the panel’s foreheads and its influence on the shear resistance by using four numerical models. The numerical models are compared and verified with two experiments. The first experiment is vacuum loading on the hollow core slab. Second experiment is about shear loading by applying the loading blocks. Four methods for design of hollow core panels are evaluated. It is the method based on main stresses, design according EN 1992 and EN 1168 and Yang’s method of prestress effects transfer. Based on the results, a method of considering flexural support for the evaluation of hollow core panels is proposed.
|
|
Jet Grouting
Kubín, Tomáš ; Boštík, Jiří (referee) ; Glisníková, Věra (advisor)
The aim of this thesis is to describe jet grouting. There are specified base methods of ground improvement and described possibilities of jet grouting. Furthermore thesis is focused on certain constructions and reconstructions in Brno, where this method was used. In detail it is concerned on reconstruction of the palace of Chlumecky, where jet grouting was used as shoring of foundation pit. Next part of this thesis is a numerical model of this foundation pit and comparison of the results from different constitutive models of soil.
|
|
Energy Piles
Buzgóová, Ivana ; Miča, Lumír (referee) ; Boštík, Jiří (advisor)
In the first part of bachelor thesis, a concept of energy pile is explained and also basic information about usage of geothermal energy, montage of pile, its design and the overall operation of the system is shown. Behaviour of axially loaded energy piles is observed in the individual section. In contrast with other foundation structures, energy piles are also under thermal loading. Next, the main factors of pile behaviour are mentioned, the methods of investigation of energy piles (analytical, experimental and numerical) are described and also characteristics, results from the specific studies that were made in different parts of the world under various conditions. In the second part of the thesis, a simple numerical analysis of energy pile is carried out. The simulation of pile is performed in Plaxis 2D. The description of model, calculation phases are discussed along with achieved results and compared with published studies.
|
|
Analysis of factors influencing internal forces in primary tunnel lining and its design
Rozmánek, Filip ; Rychtecký, Josef (referee) ; Chalmovský, Juraj (advisor)
This thesis deals with the mathematical modelling of the primary lining of a tunnel which finds itself in overconsolidated neogenic clay. This type of construction is typically solved by a combination of linear-elastic beams representing sprayed concrete and a linear elastic – perfectly plastic soil material model. Both of these approaches are a simplification of the behaviour of both sprayed concrete and soil. The real behaviour of concrete is nonlinear and time-dependent when it comes to stiffness and strength. In praxis, this issue is solved by implementing phases of young and cured concrete. The real behaviour of soils is, on the other hand, influenced by hardening. The main goal of this thesis is to use an advanced time-dependent elastoplastic material model (The Concrete model) to create shotcrete lining for the Dřevnovice tunnel, built by the Kernbauweise method. A nonlinear hyperbolic soil material model (The Hardening Soil model) is applied to the neogenic clay environment. Various modelling approaches are used to obtain internal forces and deformations of tunnel lining. These approaches are then graphically compared. The last part of this thesis focuses on verifying the primary lining design of a railway tunnel in central Moravia.
|
|
Defects of railway embankments resulting from their widening in the past
Buzgóová, Ivana ; Grepl, Jan (referee) ; Štefaňák, Jan (advisor)
First chapter of this master's thesis describes specific features of railway embankments in the past and it creates basics for appropriate understanding of following parts. Next, historical development of dimensions of railway platform is introduced. Historical development of dimensions is expected to be a possible reason in field of defects of embankments. Separate chapter refers to various locations in Czech republic where defects of railway embankments can be detected. Description contains not only defects of embankments but also ways of rehabilitation that were performed. Subsequently, the methods of rehabilitation of railway embankments are stated in regard to SŽ S4. In second part of the master's thesis, rehabilitation arrangement of particular railway embankment is designed. It is situated in Česká Kamenice in Děčín region. A numerical simulation of embankment is carried out in Plaxis 2D. The description of model and acquired results are given.
|