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Analysis of the thermal load of the workpiece during the cutting grinding of high-strength bearing rings
Felgentreu, Sven ; Blecha, Petr (advisor)
Práce se zabývá tepelným namáháním valivých ložisek s vysokou pevností, které jsou řezány pomocí brusného kotouče. Při lineárním způsobu řezání brousícím kotoučem značně vzrůstá teplota podél střižnice. Takto vzniklé teplo se hromadí v malém průřezu materiálu a dochází k tepelnému ovlivnění okolí místa řezu. Cíl této práce spočívá v navržení dvouosého řezání kotoučem za účelem snížit tepelné poškození materiálu. Nejdříve byl teoreticky posouzen současný postup řezání a na základě toho navržena dvouosá řezací strategie, která byla poté experimentálně ověřena. Použitím dvouosé strategie je možné dosáhnout významné redukce nárůstu teploty ve střižné ploše tak, že materiál není tepelně poškozen a současně nevzniká otřep. Nicméně, dvouosý způsob řezání vede ke zvýšení doby procesu, jenž je tedy nutné dále optimalizovat.
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Simulation of a temperature field of the FDM printhead
Rousek, Jakub ; Dvořák, Jaromír (referee) ; Zemčík, Oskar (advisor)
The aim of this thesis is to analyze the thermal behaviour of the printhead used on RepRap 3D printers. The main focus was on heatbreak zone, where are located important processes in terms of softening and melting of materiál. For choosed printheads is looked at effect of their design on the temperature profile and lenght of thermoplastic transition phase. For the purpose of simulations, 3D models were created using CAD system. These models were then used as vase for the simulation models of temperature distribution and spreading. The prinhead used for CR10 printer reach significantly worse result of heat distribution in heatbreak for model with bolt attachment between heat block and heatsink. This attachment is increasing temperature at the bottom of of heatsink and also increasing length of transition zone. The same attachment is look at for the second type of printhead – A10M. Here is difference less noticable. The heat transfer by attachment bolts is compenzated by reducing thickness of wall in the heatbreaks. For the printhead type diamond was deemed necessery usage of insulation materiál between heat block and rst of the components. Insufficient insulation is increasing risk of clogging and thermal damage to construction supporting fan.
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Energy consumption of equipressure and various pressures technical alcohol distillation
Audy, Dan ; Leštinský, Pavel (referee) ; Smejkal, Quido (advisor)
This hork compares the heat consumption of two units for the production of technical alcohol. The aim is to compare ordinary arrangement of rectifying distillery with an alternative arrangement, based on a modified pressure device profile. The first unit is based on the classic arrangement brewhouse, working at atmospheric pressure. The alternative unit works with different pressures in columns. In this case, the pressures are chosen so that it was possible to use heat from the head of overpressure rectification column for reboiler of vacuum mash column. The principle of pressure differences between the two columns and appropriate choice for this difference also allows the beneficial use of surplus heat. It also reduces the risk of clinkering incrusts in reboiler mash column because this works at lower temperatures than the mash column atmospheric embodiment. The comparisons of the media in this work are: The amount of steam used for reboilers of both columns, the amount of cooling water used for condensation and cooling of process streams. Furthermore, an approximate estimate of electricity consumption for pumps and other machinery. For both units is considered the same amount of mash and the same amount of product of comparable quality. The product was a technical alcohol 96.4% aa at a temperature of 25 ° C.
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Using thermochromic systems for testing heat distribution
Klimeš, Jan ; Sedlaříková, Marie (referee) ; Zatloukal, Miroslav (advisor)
This thesis deals with principles of thermochromism and its possible applications in heat distribution testing. Theoretical part describes mechanisms which allow the thermochromic properties of the substances. Particular attention is paid to cholesteric liquid crystals. Ability to measure the heat for this type of liquid crystals was varified. Also long service life in high humidity environment, enviroment with intense UV radiation, cyclic changes in temperature or immersion in water was tested. A possibility of their practical use in diagnosis was verified as well. Specifically mapping of heat distribution on an assembled PCB. Conclusion contains comparison and evaluation of this method in terms of accuracy, user comfort and economic advantages compared to conventional infrared sensors.
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Design of heated print bed for FDM 3D printer with FEM simulation
Bartoš, Radko ; Slaný, Martin (referee) ; Zemčík, Oskar (advisor)
Master´s thesis deals with desing of a heated bed for FDM 3D printer using the finite element method. It is briefly described the history of RepRap printers, construction and mechanical parts. Are discussed two methods of heating, heated by PCB boards and using power resistors. Furthermore is work closely focused on power resistors. There are presented methods and procedures which leads to an optimal distribution of heated components on the board of heated bed. In conclusion are presented results of testing which are compared with the simulations in ANSYS.
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Simulation of a temperature field of the FDM printhead
Rousek, Jakub ; Dvořák, Jaromír (referee) ; Zemčík, Oskar (advisor)
The aim of this thesis is to analyze the thermal behaviour of the printhead used on RepRap 3D printers. The main focus was on heatbreak zone, where are located important processes in terms of softening and melting of materiál. For choosed printheads is looked at effect of their design on the temperature profile and lenght of thermoplastic transition phase. For the purpose of simulations, 3D models were created using CAD system. These models were then used as vase for the simulation models of temperature distribution and spreading. The prinhead used for CR10 printer reach significantly worse result of heat distribution in heatbreak for model with bolt attachment between heat block and heatsink. This attachment is increasing temperature at the bottom of of heatsink and also increasing length of transition zone. The same attachment is look at for the second type of printhead – A10M. Here is difference less noticable. The heat transfer by attachment bolts is compenzated by reducing thickness of wall in the heatbreaks. For the printhead type diamond was deemed necessery usage of insulation materiál between heat block and rst of the components. Insufficient insulation is increasing risk of clogging and thermal damage to construction supporting fan.
|
|
|
Using thermochromic systems for testing heat distribution
Klimeš, Jan ; Sedlaříková, Marie (referee) ; Zatloukal, Miroslav (advisor)
This thesis deals with principles of thermochromism and its possible applications in heat distribution testing. Theoretical part describes mechanisms which allow the thermochromic properties of the substances. Particular attention is paid to cholesteric liquid crystals. Ability to measure the heat for this type of liquid crystals was varified. Also long service life in high humidity environment, enviroment with intense UV radiation, cyclic changes in temperature or immersion in water was tested. A possibility of their practical use in diagnosis was verified as well. Specifically mapping of heat distribution on an assembled PCB. Conclusion contains comparison and evaluation of this method in terms of accuracy, user comfort and economic advantages compared to conventional infrared sensors.
|
|
|
Analysis of the thermal load of the workpiece during the cutting grinding of high-strength bearing rings
Felgentreu, Sven ; Blecha, Petr (advisor)
Práce se zabývá tepelným namáháním valivých ložisek s vysokou pevností, které jsou řezány pomocí brusného kotouče. Při lineárním způsobu řezání brousícím kotoučem značně vzrůstá teplota podél střižnice. Takto vzniklé teplo se hromadí v malém průřezu materiálu a dochází k tepelnému ovlivnění okolí místa řezu. Cíl této práce spočívá v navržení dvouosého řezání kotoučem za účelem snížit tepelné poškození materiálu. Nejdříve byl teoreticky posouzen současný postup řezání a na základě toho navržena dvouosá řezací strategie, která byla poté experimentálně ověřena. Použitím dvouosé strategie je možné dosáhnout významné redukce nárůstu teploty ve střižné ploše tak, že materiál není tepelně poškozen a současně nevzniká otřep. Nicméně, dvouosý způsob řezání vede ke zvýšení doby procesu, jenž je tedy nutné dále optimalizovat.
|
|
|
Design of heated print bed for FDM 3D printer with FEM simulation
Bartoš, Radko ; Slaný, Martin (referee) ; Zemčík, Oskar (advisor)
Master´s thesis deals with desing of a heated bed for FDM 3D printer using the finite element method. It is briefly described the history of RepRap printers, construction and mechanical parts. Are discussed two methods of heating, heated by PCB boards and using power resistors. Furthermore is work closely focused on power resistors. There are presented methods and procedures which leads to an optimal distribution of heated components on the board of heated bed. In conclusion are presented results of testing which are compared with the simulations in ANSYS.
|
|
|
Energy consumption of equipressure and various pressures technical alcohol distillation
Audy, Dan ; Leštinský, Pavel (referee) ; Smejkal, Quido (advisor)
This hork compares the heat consumption of two units for the production of technical alcohol. The aim is to compare ordinary arrangement of rectifying distillery with an alternative arrangement, based on a modified pressure device profile. The first unit is based on the classic arrangement brewhouse, working at atmospheric pressure. The alternative unit works with different pressures in columns. In this case, the pressures are chosen so that it was possible to use heat from the head of overpressure rectification column for reboiler of vacuum mash column. The principle of pressure differences between the two columns and appropriate choice for this difference also allows the beneficial use of surplus heat. It also reduces the risk of clinkering incrusts in reboiler mash column because this works at lower temperatures than the mash column atmospheric embodiment. The comparisons of the media in this work are: The amount of steam used for reboilers of both columns, the amount of cooling water used for condensation and cooling of process streams. Furthermore, an approximate estimate of electricity consumption for pumps and other machinery. For both units is considered the same amount of mash and the same amount of product of comparable quality. The product was a technical alcohol 96.4% aa at a temperature of 25 ° C.
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