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Woodgas cooler
Koláček, Martin ; Toman, Filip (referee) ; Lachman, Jakub (advisor)
This bachelor thesis deals with problematics of designing a cooler suitable for gas produced by gasification of biomass. The current state of knowledge is presented in research part of this thesis. Subsequent design segment contains detailed calculations, design and construction solution of cooler suitable for producer gas. Cooling of gas created by biomass gasification is more problematic than cooling of pure gases or water vapor because producer gas contains many impurities that condense during cooling process and settle inside cooler. Thus, complicating design of effective cooling device. Our motivation for cooling producer gas is increasing its energy density and decreasing its volume. Basic technical documentation of designed cooler is also part of this thesis.
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Design concept of the facility for the educational objectives of the boiling crisis
Vojáčková, Jitka ; Škorpík, Jiří (referee) ; Martinec, Jiří (advisor)
This thesis deals with a design concept of the facility for the educational objectives of the boiling crisis. In the first part, the issue of boiling crisis is explained. There are also examples of some experimental facilities in the world. The second part includes design concept of a loop, which is accompanied by designs of individual devices, such as separator, condenser, exchanger, pump, water tank, electric heater. The thesis also states designs of throttle control, temperature control and flow control.
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Heat transfer in the tubular exchangers
Horvát, Petr ; Krištof, Ondřej (referee) ; Svěrák, Tomáš (advisor)
Shell and tube heat exchangers and their use in cooling processes are the major topic of this thesis. The theoretical part of the thesis starts with the mechanisms of heat transfer and then deals with shell and tube heat exchangers. Their position, design specifications and equations for calculations are given. In the experimental part, the heat transfer on semi-operating shell and tube heat exchangers with baffles and glass or silicon carbide heat exchange surface is examined by cooling the humid air by 50% propylene glycol in tubes. For four or five coolant flows and three airflows, input and output flow temperatures including relative air humidity were measured. Differences in exchanged heat between the exchangers were negligible due to the low local air heat transfer coefficient, although silicon carbide has two orders of magnitude better thermal conductivity than glass. Much higher efficiency was performed by the carbide heat exchanger because the difference between air outlet temperature and liquid inlet temperature was one and half times higher for the glass heat exchanger. That was reflected in a decrease in mean temperature difference, which resulted in a 16 % higher experimental heat transfer coefficient compared with the glass surface. The theoretical model using the j factor, the correction factors for the baffles, and the correction for air humidity condensation have proven to be appropriate. For the glass surface, for the highest air flow rates the model gives an appropriate heat-transfer coefficient; at lower flow rates it gives slightly higher values. For the silicon carbide surface, it gives a lower heat-transfer coefficient because the model failed to consider a lower mean temperature difference. The results also evaluate the heat loss through the shell and the heat exchanged in addition by air humidity condensation.
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Prediction of fluids temperature profiles in heat exchanger
Havelková, Pavla ; Kilkovský, Bohuslav (referee) ; Jegla, Zdeněk (advisor)
This master’s thesis is focused on the description and processing of the cell method, which is generally recommended for prediction of fluids temperature profiles in heat exchanger. In the thesis the basic equations for calculating heat transfer are presented and is also described the current situation in the field of computational prediction of fluids temperature profiles in heat exchangers. The cell method is solved by using the software Maple and is applied to the specific case of industrial heat exchangers. The results obtained by the cell method are compared with the results obtained by educational version of software HTRI Xchanger Suite. By this comparison explicitness of the cell method is assessed.
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Heat exchanger conversion for new media
Guliš, Jan ; Toman, Filip (referee) ; Baláš, Marek (advisor)
This thesis deals with calculation of the existing tube heat exchanger conversion for new media air-water. The theoretical part is devoted to the introduction to the topic of heat exchangers and deals with their basic divisions including descriptions of various types of design. The heat and hydraulic calculation for usage of new media is processed in the second part. The conclusion of the thesis is the result evaluation and proposal of the heat exchanger modifications which could lead to higher efficiency. The thesis includes an appendix with technical documentation of heat exchanger.
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Heat exchanger design to improve the efficiency of industrial plant
Hofbauer, Jan ; Kilkovský, Bohuslav (referee) ; Freisleben, Vít (advisor)
In thesis is done thermal-hydraulic design of cross-flow tubular heat exchanger for combustion air preheating. In software Chemcad is done simulation of technological unit based on known operating data, which is used for behavior prediction of unit after heat exchanger installation. Then there are discussed essential mechanisms of heat transfer. After that there is overview of different heat exchanger types used for combustion air preheating. Before particular design there is performed optimalization of heat duty of heat exchnger based on payback time. Thermal-hydraulic design is performed using F-LMTD method in software GNU Octave. Obtained results are verified using software HTRI Xchanger Suite®. At the end there are discussed economical and ecological benefits of designed heat exchanger.
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Condensation heat transfer of water steam on cylindrical wall
Horká, Lucie ; Bašta,, Jiří (referee) ; Kabele,, Karel (referee) ; Hirš, Jiří (advisor)
The doctoral thesis is aimed at condensation heat transfer of water steam on a cylindric wall. This physical phenomenon of water steam condensation is examined and published in leading scientific journals for more than 100 years. The main aim of the doctoral thesis is study of the water steam condensation on a cylindrical wall. The result of the doctoral thesis is the theoretical and experimental determination of the heat transfer coefficient during the water steam condensation on the cylindrical wall. This coefficient is a basic parameter of design of all the thermal devices, which use the condensation heat of water steam in technical practice.
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Heat exchanger design to improve the efficiency of industrial plant
Hofbauer, Jan ; Kilkovský, Bohuslav (referee) ; Freisleben, Vít (advisor)
In thesis is done thermal-hydraulic design of cross-flow tubular heat exchanger for combustion air preheating. In software Chemcad is done simulation of technological unit based on known operating data, which is used for behavior prediction of unit after heat exchanger installation. Then there are discussed essential mechanisms of heat transfer. After that there is overview of different heat exchanger types used for combustion air preheating. Before particular design there is performed optimalization of heat duty of heat exchnger based on payback time. Thermal-hydraulic design is performed using F-LMTD method in software GNU Octave. Obtained results are verified using software HTRI Xchanger Suite®. At the end there are discussed economical and ecological benefits of designed heat exchanger.
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Heat exchanger conversion for new media
Guliš, Jan ; Toman, Filip (referee) ; Baláš, Marek (advisor)
This thesis deals with calculation of the existing tube heat exchanger conversion for new media air-water. The theoretical part is devoted to the introduction to the topic of heat exchangers and deals with their basic divisions including descriptions of various types of design. The heat and hydraulic calculation for usage of new media is processed in the second part. The conclusion of the thesis is the result evaluation and proposal of the heat exchanger modifications which could lead to higher efficiency. The thesis includes an appendix with technical documentation of heat exchanger.
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Heat transfer in the tubular exchangers
Horvát, Petr ; Krištof, Ondřej (referee) ; Svěrák, Tomáš (advisor)
Shell and tube heat exchangers and their use in cooling processes are the major topic of this thesis. The theoretical part of the thesis starts with the mechanisms of heat transfer and then deals with shell and tube heat exchangers. Their position, design specifications and equations for calculations are given. In the experimental part, the heat transfer on semi-operating shell and tube heat exchangers with baffles and glass or silicon carbide heat exchange surface is examined by cooling the humid air by 50% propylene glycol in tubes. For four or five coolant flows and three airflows, input and output flow temperatures including relative air humidity were measured. Differences in exchanged heat between the exchangers were negligible due to the low local air heat transfer coefficient, although silicon carbide has two orders of magnitude better thermal conductivity than glass. Much higher efficiency was performed by the carbide heat exchanger because the difference between air outlet temperature and liquid inlet temperature was one and half times higher for the glass heat exchanger. That was reflected in a decrease in mean temperature difference, which resulted in a 16 % higher experimental heat transfer coefficient compared with the glass surface. The theoretical model using the j factor, the correction factors for the baffles, and the correction for air humidity condensation have proven to be appropriate. For the glass surface, for the highest air flow rates the model gives an appropriate heat-transfer coefficient; at lower flow rates it gives slightly higher values. For the silicon carbide surface, it gives a lower heat-transfer coefficient because the model failed to consider a lower mean temperature difference. The results also evaluate the heat loss through the shell and the heat exchanged in addition by air humidity condensation.
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