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Thermal insulation and backfilling as a way to save metal and anergy in foundry
Kos, Jan ; Sekanina, Bohumil (referee) ; Kavička, František (advisor)
Types were summarized, principles and thermo-physical properties of thermal insulation and backfilling and their use in the foundry industry to provide directionally solidified castings and then their quality. It summarized the need for numerical simulation of thermal field system casting-form (core)-around the control and prediction of directional solidification. They are some commercial software using different models of solidification. As an example, using one of the models describe the procedure as a pre calculation to decide which of two possible isolation of the riser will be more effective.
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Optimization of Slab Concasting Via Numerical Model of Temperature Field
Mauder, Tomáš ; Čarnogurská, Mária (referee) ; Pyszko, René (referee) ; Raudenský, Miroslav (referee) ; Kavička, František (advisor)
The thesis deals with optimization of the continuous slab casting process. The thesis summarizes the basic analytical and empirical findings concerning to the solidification process, the numerical modeling and the selected optimization techniques. Physical conditions and factors that affect the quality of steel including their relationships are also described. The basis of the solution strategy is the original numerical model of the temperature field in its off-line version. The numerical model was verified by the real historical data. The optimization part is based on the fuzzy logic implemented above the numerical model. The optimization algorithm is used for the optimal control of the casting process. The universal usage of the optimization model is demonstrated on several cases, e.g. the finding of optimal casting parameters that ensure the high quality of products, the optimal reactions on breakdown situations, the determination of an optimal relationship between casting parameters, etc. Based on optimization results, the suitable caster modification to increase the surface temperature at the unbending point was proposed. The whole concept of the numerical and optimization model is general and it can be applied to arbitrary slab or billet continuous casting.
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The used principles of industrial cooling
Machala, Jiří ; Sekanina, Bohumil (referee) ; Kavička, František (advisor)
This thesis summarizes the main cooling methods used in industrial cooling systems. It also discusses the fluids used in cooling, their influence on environment; ozone layer and climate change. The thesis closely describes the properties of ammonia and out of the many cooling methods on the market, it mostly concentrates on ammonia cooling systems. The thesis also discusses heat pumps, vortex tubes, and thermoelectric cooling.
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Research of Systems for Providing the Quality of the Environment in the Car Cabin
Šíp, Jan ; Kavička, František (referee) ; Volavý, Jaroslav (referee) ; Lízal, František (advisor)
Optimal conditions of indoor environmental quality, especially thermal comfort and indoor air quality, are important because they lead to the active safety of passengers. Long-term exposure to inconvenient temperatures may cause thermal stress and negatively affects the driver’s cognitive functions. These include important abilities of drivers, such as concentration, vigilance, speed of decision-making and others. The inappropriate temperature in the cabin is one of the most dangerous factors causing car crashes. Air indoor quality is negatively affected by exhaust gases or particles from tire wear, which enter the car cabin during ventilation. This can be prevented by using an air recirculation system which does not supply outside air, but it is a closed circuit. This mode, however, causes high CO2 concentration in the cabin which can lead to excessive fatigue. This thesis deals with the influence of different ventilation systems on indoor environmental quality, i. e. thermal comfort and indoor air quality. A partial factor of thermal comfort is the flow field which was investigated downstream of a benchmark automotive vent. CFD was applied to determine the flow field downstream of a vent. The results were validated by experimental data acquired by Constant Temperature Anemometry. CFD has been also used for the evaluation of the thermal comfort of three novel ventilation systems (mixing, ceiling and floor ventilation). The results were validated by experimental data acquired by thermal manikin and climate chamber. Indoor air quality has been evaluated based on the Age of Air. The analytical empirical equation by Rajaratnam can be successfully used also to determine the throw of the jet, which is favorable, especially in light of the fact that both computational methods were not very accurate in velocity decay predictions. The Large Eddy Simulation and Reynolds-averaged Navier–Stokes method are suitable for evaluating the flow field downstream of the automotive vent. The diagrams of comfort zones were evaluated for all regimes based on equivalent temperatures. The best performance in terms of the highest level of human comfort was achieved by the ceiling ventilation in the summer conditions and by the floor ventilation in the winter conditions. From the point of view of the Age of Air, the ceiling air ventilation system is the most suitable for the winter conditions. In the summer conditions the Age of Air values for individual air ventilation concepts are very similar for both interior types.
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Optimization of Slab Concasting Via Numerical Model of Temperature Field
Mauder, Tomáš ; Čarnogurská, Mária (referee) ; Pyszko, René (referee) ; Raudenský, Miroslav (referee) ; Kavička, František (advisor)
The thesis deals with optimization of the continuous slab casting process. The thesis summarizes the basic analytical and empirical findings concerning to the solidification process, the numerical modeling and the selected optimization techniques. Physical conditions and factors that affect the quality of steel including their relationships are also described. The basis of the solution strategy is the original numerical model of the temperature field in its off-line version. The numerical model was verified by the real historical data. The optimization part is based on the fuzzy logic implemented above the numerical model. The optimization algorithm is used for the optimal control of the casting process. The universal usage of the optimization model is demonstrated on several cases, e.g. the finding of optimal casting parameters that ensure the high quality of products, the optimal reactions on breakdown situations, the determination of an optimal relationship between casting parameters, etc. Based on optimization results, the suitable caster modification to increase the surface temperature at the unbending point was proposed. The whole concept of the numerical and optimization model is general and it can be applied to arbitrary slab or billet continuous casting.
|
|
|
Optimization of Slab Concasting Via Numerical Model of Temperature Field
Mauder, Tomáš ; Kavička, František (advisor)
The thesis deals with optimization of the continuous slab casting process. The thesis summarizes the basic analytical and empirical findings concerning to the solidification process, the numerical modeling and the selected optimization techniques. Physical conditions and factors that affect the quality of steel including their relationships are also described. The basis of the solution strategy is the original numerical model of the temperature field in its off-line version. The numerical model was verified by the real historical data. The optimization part is based on the fuzzy logic implemented above the numerical model. The optimization algorithm is used for the optimal control of the casting process. The universal usage of the optimization model is demonstrated on several cases, e.g. the finding of optimal casting parameters that ensure the high quality of products, the optimal reactions on breakdown situations, the determination of an optimal relationship between casting parameters, etc. Based on optimization results, the suitable caster modification to increase the surface temperature at the unbending point was proposed. The whole concept of the numerical and optimization model is general and it can be applied to arbitrary slab or billet continuous casting.
|
|
|
Thermal insulation and backfilling as a way to save metal and anergy in foundry
Kos, Jan ; Sekanina, Bohumil (referee) ; Kavička, František (advisor)
Types were summarized, principles and thermo-physical properties of thermal insulation and backfilling and their use in the foundry industry to provide directionally solidified castings and then their quality. It summarized the need for numerical simulation of thermal field system casting-form (core)-around the control and prediction of directional solidification. They are some commercial software using different models of solidification. As an example, using one of the models describe the procedure as a pre calculation to decide which of two possible isolation of the riser will be more effective.
|
|
|
The used principles of industrial cooling
Machala, Jiří ; Sekanina, Bohumil (referee) ; Kavička, František (advisor)
This thesis summarizes the main cooling methods used in industrial cooling systems. It also discusses the fluids used in cooling, their influence on environment; ozone layer and climate change. The thesis closely describes the properties of ammonia and out of the many cooling methods on the market, it mostly concentrates on ammonia cooling systems. The thesis also discusses heat pumps, vortex tubes, and thermoelectric cooling.
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