|
|
Model predictive Control for continuous casting of steel
Zemanová, Hana ; Mauder, Tomáš (referee) ; Štětina, Josef (advisor)
In this thesis an equation of heat conduction including phase and structural changes is derived, involving various boundary conditions. It seems to be the most suitable to calculate the equation by enthalpy method. In this equation not only enthalpy occurs, but also the temperature, and in consequence the relationship between these variables is quite complicated. In this paper I use the values measured or calculated using solidifcation models. The calculation is implemented in Matlab Simulink, which is a very popular blocks scheme in common practice of regulation. The calculation is based on steady state set up with help of experts and as a result, the program could be put into practice. The program calculates the intensity of cooling according to the initial casting speed, casting inlet temperature and the desired temperature curves. The rate of inuence of cooling can be changed according to the given criteria. The thesis compares the surface temperatures and cooling in the case of a predictive controller is or is not applied in the program.
|
|
|
Passive heat dissipation using carbon-based material
Genco, Ondřej ; Brázdil, Marian (referee) ; Pospíšil, Jiří (advisor)
The content of the diploma thesis is evaluation of the usability of carbon composites in the space industry. The aim of this work is to assess whether carbon composites can find application in mechanical systems of passive thermal protection of artificial objects. Model examples demonstrate the principle of operation of selected passive thermal protection. The evaluation is realized based on the results of thermal analysis. Analytical formulas from field theory of heat transfer are used as a calculation method. The diploma thesis consists from two parts. The theoretical part briefly describes the mechanisms of heat transfer, selected types of passive thermal protection and properties and applications of carbon composites. The practical part consists of the assignment, calculation and evaluation of three examples. The results show that carbon composites can compete with commonly used materials for specific requirements.
|
|
|
Thermal Losses of the Biomass Boiler
Suchánková, Lenka ; Milčák, Pavel (referee) ; Kracík, Petr (advisor)
The bachelor thesis focuses on the heat loss of the solid fuel boiler, especially on the loss of heat conduction and transfer to the surroundings. In order to minimalize thermal leaks through the boiler walls, materials with good isolation capabilities must be selected when designing. In Microsoft Excel, a universal mathematical model was created to calculate the heat flux flowing through the flat wall of the boiler, from which temperatures can be obtained on the inside of the wall. The work describes the calculation method on which the model is based and its correctness is verified on an experiment based on sensing of temperature fields of wall sur-faces of equipment burning biomass by thermal camera. The model can be used for a wall with up to 9 layers of material, where the wall can be cooled (heat loss) by air and water.
|
|
|
Design of optimal parameters of multilayer ceramic protective coating for high temperature applications
Dohnalík, Petr ; Hrstka, Miroslav (referee) ; Ševeček, Oldřich (advisor)
The main objective of this work was to design a suitable composition of a protective coatings, made of several different layers of specific materials - with respect to residual stress, induced due to a mismatch in thermal expansion coefficients of each layer. Protective coating in this work means both the thermal and the environmental barrier. These coatings protect components against high temperatures and harsh environment. In this work, necessary theoretical background in the field of the thermal and environmental barrier coatings is introduced. There are mentioned some basic design approaches, commonly used materials and processing methods for the coating structure. The literature review gives an overview of modeling of such coated structures, in particular it is devoted to the thermal barrier coatings deposited by air plasma spray process. The next chapter closely describes classical laminate theory used for calculation of residual stresses in the coating. One of the assumptions of this theory is homogenous temperature field through the coating’s thickness. However, in this work was revealed a way to extend the classical lamination theory of such cases, in which the temperatures vary along the thickness of the coating. In the practical part, the analytical model was used for designing suitable properties of some coatings, which were consists of two, three and four layers. The calculations were performed both for constant temperature and for the temperature gradient. All results obtained from analytical approach were verified by numerical calculations.
|
|
|
A Stefan problem of heat conduction with phase change and its exact solution
Kesler, René ; Mauder, Tomáš (referee) ; Klimeš, Lubomír (advisor)
This bachelor's thesis deals with analytical solutions of heat conduction problems with phase change which are known as classical Stefan problems. At the beginning a differential equation of heat conduction is derived and a mathematical model of Stefan problem is formed. The greatest attention is paid to the derivation of analytical solutions for cases in which these solutions are obtainable. The MATLAB environment was chosen for implementation of the obtained solutions. The thesis also includes a description of the program and its graphical interface in MATLAB. The applicability of the program is demonstrated in several phase change problems.
|
|
|
Apparatus for measuring the thermal resistance of the gloves
Pelikán, Jakub ; Fišer, Jan (referee) ; Hejčík, Jiří (advisor)
This thesis deals with common problem health protection at work. Namely hand protection during the work in very cold environment. It’s an analysis of materials suitable for apparatus used for measuring the thermal resistance of the gloves. There was analysed a range of materials. Every single sample was tested for heat conductivity and afterwards was assessed the suitability of materials. Heat was generated by electricity. Ocured heat fields was assessed with thermocamera. After performed experiments of carbon fiber we haven’t reached any satisfying results which we could use for manufacturing of this device. On the other hand kapton film has given very interesting results which we would recommend eventually. Kapton film needs to be modify according to the method listed in the conlusion. This thesis gives us a clear overview and inspiration for additional research of this device. It finds it’s place in research facilities and companies manufacturing protective clothing.
|
|
|
Heuristic Algorithms in Optimization
Komínek, Jan ; Šeda, Miloš (referee) ; Roupec, Jan (advisor)
This diploma thesis deals with genetic algorithms and their properties. Particular emphasis is placed on finding the influence of mutation and population size. Genetic algorithms are applied on inverse heat conduction problems (IHCP) in the second part of the thesis. Several different approaches and coding methods were tested. Properties of genetic algorithms were improved by definition of two new genetic operators – manipulation and sorting. Reported theoretical findings were tested on the real data of inverse heat conduction problem. The library for easy implementation of GA for solving general optimization problems in C ++ was created and is described in the last chapter.
|
|
|
Výpočet tepelných ztrát obvodovým pláštěm dřevostavby a teplotního pole ve vybraných konstrukčních detailech
Pokora, Radek
This diploma thesis clarifies a description of thermal field in a construction of wooden building and deals with heat loss issue in an envelope of a building in specificed constructions detailes. You can find in this thesis description of thermal diffusivity in buildings constructions. The task is to create 3-D models of selected construction details of selected wooden building. In those detailes, based on finite element method is created thermal field and thermal flux. And the calculation of heat loss in those construction details. A family house and a house envelope are designed by myself and simulations are made on that family house. I needed to know a boundary settings and heat transfer temperature gradient. The important result is what is the value of heat loss. Then I need to know why and what can I do to fix problém points. There are written stacionary calculations in selected detailes in the thesis. In the end is an evaluation of designed house envelope heat loss. Problem detailes are showed also.
|
|
|
Numerická analýza teplotního pole v konstrukci obvodového pláště dřevostavby rodinného domu s ohledem na možné způsoby osazování otvorových výplní
Kopal, Ondřej
This thesis describes the temperature field in the envelope wooden structures with regard to possible ways of mounting hole fillings. Furthermore, in this work we can find a description of the propagation of heat in the building structure. The challenge is to create a 2-D models of the selected design solutions for the mounting hole fillings in the envelope wooden buildings. Numerical simulation is performed in a computer software based on the finite element method under the given boundary conditions. The emphasis is on comparing the results of numerical simulations for two design solutions fitting windows using the same track of the structure. In conclusion, the results for both design solutions compared and evaluated.
|
|
|
Passive heat dissipation using carbon-based material
Genco, Ondřej ; Brázdil, Marian (referee) ; Pospíšil, Jiří (advisor)
The content of the diploma thesis is evaluation of the usability of carbon composites in the space industry. The aim of this work is to assess whether carbon composites can find application in mechanical systems of passive thermal protection of artificial objects. Model examples demonstrate the principle of operation of selected passive thermal protection. The evaluation is realized based on the results of thermal analysis. Analytical formulas from field theory of heat transfer are used as a calculation method. The diploma thesis consists from two parts. The theoretical part briefly describes the mechanisms of heat transfer, selected types of passive thermal protection and properties and applications of carbon composites. The practical part consists of the assignment, calculation and evaluation of three examples. The results show that carbon composites can compete with commonly used materials for specific requirements.
|
guest ::
