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Study of Thermal Properties of Materials
Štefková, Pavla ; Pavlík, Zbyšek (referee) ; Matiašovský, Peter (referee) ; Zmeškal, Oldřich (advisor)
The doctoral thesis deals with study of thermal properties of materials. Behavior of homogeneous matters at different temperatures is well described in theory and experimentally verified. Overall effect of all components of mixture and other influences related with material creation affect behaviour and properties of heterogeneous matters. For study of thermal properties can be used transient method of measurement which provide a picture about overall influence of all components of mixture on studied heterogeneous material and among others enable determination of thermophysical properties of whole macroscopic system in observed temperature range. Properties of solid matters, thin foil and liquids can be measured by means of pulse and step-wise transient method which is used for experimental activity in the thesis. It is contact measurement method and its principle is based on small quantity of heat generating inside the specimen and temperature response measuring. Theoretical part of thesis is focused on creation of method for determination of thermophysical parameters. The base is differential equation of the heat conduction. Its solution is temperature function. Three methods of evaluation are described mathematically. They start from general relations designed for study of fractal structure physical properties (maximum of function method, differential method and multi-parametric non-linear regression method).
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Study of thermal properties of selected coloids
Křivánková, Kateřina ; Krouská, Jitka (referee) ; Zmeškal, Oldřich (advisor)
The bachelor thesis is focused on the study of the thermal properties of colloidal systems, especially the properties of emulsions (water, oil), which can be used in the cosmetic industry as an essential component of various lotions and creams and in the food industry. In the introduction the first defined thermo-physical processes (conduction, convection and radiation) and temperature measurement (stationary, transient). Furthermore defined physical parameters (heat and thermal conductivity, heat capacity), that are determined using transient methods. The measured data were collected and analyzed by using the EMA (Electrical Measurement Analyser) and the HarFA (Harmonic and Fractal Image Analyser). The results will be used to determine the optimum conditions for the production of cosmetics and dietary supplements.
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Thermo-physical parameters of exo-sleeves and their application in simulation programmes
Zajíček, Roman ; Kuzma, Zbyněk (referee) ; Roučka, Jaromír (advisor)
Thesis discusses exothermic sleeves. The first chapter briefly described the defects can occur during solidification. Further, there are provided methods for removing these defects. The method is described in detail using risers with an emphasis on the exothermic sleeves and thermo-physical parameters characterizing these sleeves. It also describes the influence of these parameters on the accuracy of computer simulations. In the final part of the work is done measuring of the real casting, which is then simulated in the Quikcast.
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Study of thermal properties of phase change materials
Křivánková, Kateřina ; Krouská, Jitka (referee) ; Zmeškal, Oldřich (advisor)
The diploma thesis studies the thermal properties of materials, heat storage based on phase transformation. The aim of this study was to measure the thermal properties of materials using a heat accumulation phase transformation, particularly a commercial material available from the Phase Change Material Products Ltd. under the name PlusICE A118. Such materials are referred to as PCM (from Eng. Phase Change Material), and are used for instance as heat insulators in construction. First described the phase transformation of substances in general, then was defined accumulation of thermal energy. We have also described methods for determining the temperature (thermal analysis, stationary and transietní methods). Finally defined thermophysical parameters (thermal capacity, thermal conductivity, thermal conductivity), which were determined transient step method.
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Influence of exothermic sleaves on solidification of aluminium alloys
Zajíček, Roman ; Krutiš, Vladimír (referee) ; Roučka, Jaromír (advisor)
The master’s thesis deals with the influence of the exothermic risers on the solidification of aluminum alloys. The work is divided into three parts. The first theoretical part describes the differences of properties of cast aluminum alloys compared to other based metals, especially iron alloys. It also describes the methodology of designing risers, composition of exothermic mixtures and finally gives an overview on the simulation programs on the market, their application in foundry practice and briefly explains how to define the material in the simulation program ProCAST. The second part describes the experimental measurement of the solidification time of aluminum alloy AlSi7Mg0,3 in the sand form with exothermic riser. The final section describes the simulation of experimental measurements. Further with help of simulation software it is tried to find the general principles that have an influence on feed module rate of exothermic riser.
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Study of thermal properties of phase change materials
Křivánková, Kateřina ; Krouská, Jitka (referee) ; Zmeškal, Oldřich (advisor)
The diploma thesis studies the thermal properties of materials, heat storage based on phase transformation. The aim of this study was to measure the thermal properties of materials using a heat accumulation phase transformation, particularly a commercial material available from the Phase Change Material Products Ltd. under the name PlusICE A118. Such materials are referred to as PCM (from Eng. Phase Change Material), and are used for instance as heat insulators in construction. First described the phase transformation of substances in general, then was defined accumulation of thermal energy. We have also described methods for determining the temperature (thermal analysis, stationary and transietní methods). Finally defined thermophysical parameters (thermal capacity, thermal conductivity, thermal conductivity), which were determined transient step method.
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Influence of exothermic sleaves on solidification of aluminium alloys
Zajíček, Roman ; Krutiš, Vladimír (referee) ; Roučka, Jaromír (advisor)
The master’s thesis deals with the influence of the exothermic risers on the solidification of aluminum alloys. The work is divided into three parts. The first theoretical part describes the differences of properties of cast aluminum alloys compared to other based metals, especially iron alloys. It also describes the methodology of designing risers, composition of exothermic mixtures and finally gives an overview on the simulation programs on the market, their application in foundry practice and briefly explains how to define the material in the simulation program ProCAST. The second part describes the experimental measurement of the solidification time of aluminum alloy AlSi7Mg0,3 in the sand form with exothermic riser. The final section describes the simulation of experimental measurements. Further with help of simulation software it is tried to find the general principles that have an influence on feed module rate of exothermic riser.
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Study of Thermal Properties of Materials
Štefková, Pavla ; Pavlík, Zbyšek (referee) ; Matiašovský, Peter (referee) ; Zmeškal, Oldřich (advisor)
The doctoral thesis deals with study of thermal properties of materials. Behavior of homogeneous matters at different temperatures is well described in theory and experimentally verified. Overall effect of all components of mixture and other influences related with material creation affect behaviour and properties of heterogeneous matters. For study of thermal properties can be used transient method of measurement which provide a picture about overall influence of all components of mixture on studied heterogeneous material and among others enable determination of thermophysical properties of whole macroscopic system in observed temperature range. Properties of solid matters, thin foil and liquids can be measured by means of pulse and step-wise transient method which is used for experimental activity in the thesis. It is contact measurement method and its principle is based on small quantity of heat generating inside the specimen and temperature response measuring. Theoretical part of thesis is focused on creation of method for determination of thermophysical parameters. The base is differential equation of the heat conduction. Its solution is temperature function. Three methods of evaluation are described mathematically. They start from general relations designed for study of fractal structure physical properties (maximum of function method, differential method and multi-parametric non-linear regression method).
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|
|
Study of thermal properties of selected coloids
Křivánková, Kateřina ; Krouská, Jitka (referee) ; Zmeškal, Oldřich (advisor)
The bachelor thesis is focused on the study of the thermal properties of colloidal systems, especially the properties of emulsions (water, oil), which can be used in the cosmetic industry as an essential component of various lotions and creams and in the food industry. In the introduction the first defined thermo-physical processes (conduction, convection and radiation) and temperature measurement (stationary, transient). Furthermore defined physical parameters (heat and thermal conductivity, heat capacity), that are determined using transient methods. The measured data were collected and analyzed by using the EMA (Electrical Measurement Analyser) and the HarFA (Harmonic and Fractal Image Analyser). The results will be used to determine the optimum conditions for the production of cosmetics and dietary supplements.
|
|
|
Thermo-physical parameters of exo-sleeves and their application in simulation programmes
Zajíček, Roman ; Kuzma, Zbyněk (referee) ; Roučka, Jaromír (advisor)
Thesis discusses exothermic sleeves. The first chapter briefly described the defects can occur during solidification. Further, there are provided methods for removing these defects. The method is described in detail using risers with an emphasis on the exothermic sleeves and thermo-physical parameters characterizing these sleeves. It also describes the influence of these parameters on the accuracy of computer simulations. In the final part of the work is done measuring of the real casting, which is then simulated in the Quikcast.
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