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Selected heat transfer phenomena in air conditioning
Vojkůvková, Petra ; Gebauer, Günter (referee) ; Šikula, Ondřej (advisor)
Numerical simulation is a scientific method used to describe characteristics of examined system by means of experiments on its mathematical model. This thesis uses this method to elucidate the processes taking place in two different systems. Firstly it deals with the design of air conditioning systems for buildings, focusing on the mixing chambers. It focuses on the formation of condensation of water vapor in mixing chambers under conditions where the final temperature of the mixture does not drop below the saturation curve. Second prepared topic falls within the field of thermodynamics applied in food production. In order to assess the sufficiency of air-cooling method examines the thermal field in the product and evaluates the application of air-cooling assembly line in practice.
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Heat dissipation axially-cooled glassmaking
Hovorka, Martin ; Pospíšil, Jiří (referee) ; Baláš, Marek (advisor)
The presented thesis deals with a numerical simulation of axially cooled glassmaking parison. Several types of cooling channels have been investigated according to its usage in glassmaking process. Software Star CCM+ was used to describe properties throughout the channels and also the parison itself. The main focus of this thesis lies in comparing of temperature fields, cooling effects and cooling intensity among the chosen channel designs. The boundary condi-tions were kept the same accordingly to glassmaking conditions for every design. Some out-puts were transferred to non-dimensional diagrams in order to recalculation pursuant to other boundary conditions. Properties of diffuser channel designs were compared to an experiment. Transient temperature field of the parison were calculated with Ansys APDL in order to de-termine the accumulation and stationary zone of the parison and to verify the boundary conditions for cooling channels.
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Interaction of microwave radiation with moisture in porous building materials
Paťha, Martin ; Šuhajdová, Eva (referee) ; Šuhajda, Karel (advisor)
This thesis deals with interaction of microwave radiation with wet in porous material. It examines the distribution of the temperature field, the efficiency of the method and the financial demands of the method. The most important part of this thesis was an experiment, from which all important values ??were based. The first part deals with the necessary theory and the second part is the experiment itself. The experiment was carried out for three levels of material wet. Eight samples were used for this experiment, which remained unchanged throughout the experiment. The thesis draws on previous researches that were carried out on this or similar topic.
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Optimalization of Exhaust Manifold for Škoda 1,2 MPI
Kubiš, Milan ; Ramík, Pavel (referee) ; Beran, Martin (advisor)
The subject of this diploma thesis is optimalization of exhaust manifold of ŠKODA 1,2 MPI engine with respect for the plastic deformation at heat stress. The first part is focused on general description of converter module, whose component the exhaust manifold is. In the next part of the thesis is computation of a heat load of the exhaust manifold. The last part is devoted to the seal analysis of the whole converter module of a ŠKODA three-cylinder engine.
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Development of Methodology for Evaluating the Necessity of Shell Compensators fo Tubular Condensers
Pernica, Marek ; Reppich, Marcus (referee) ; Vincour, Dušan (referee) ; Jegla, Zdeněk (advisor)
This dissertation deals with strength analysis of shell and tube condenser with fixed tube sheet, which is equipped with shell expansion joint. The main aim of this thesis is to develop a methodology for determining of necessity of uses the expansion joint on the shell and tube condenser, while maintaining the safety and reliability of the equipment during operation, based on thermal-hydraulic and strength analyses. Industrial condenser is used as a safety equipment during the operation, therefore special attention is paid to the start-up process. The condenser start-up process is investigated by a number of transient strength and transient thermal analyses, which was solved by specialized software and with analytical calculations. The strength calculation of shell, tube and tube-sheet of shell and tube condenser is developed in detail according the ČSN EN 13445 standard with special attention to shell and tube process media thermal impact on condenser construction. Based on the performed calculations, the methodology for evaluating the necessity of shell expansion joints of tubular condensers was developed.
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Mathematical simulation of temperature profile in the subsoil and creation of a model corresponding its real state
Charvátová, Pavlína ; Katunský,, Dušan (referee) ; Ostrý, Milan (referee) ; Čupr, Karel (advisor)
Increasing demands for low heat losses and energy intensity of a building influence energy calculations. Higher demands are placed on the accuracy of the calculations. An important part of the thermal engineering calculations is the determination of the correct boundary conditions. An important input factor is primarily the indoor and outdoor environment, and temperature is the most important parameter for these types of enviromnent. It is not always the temperature of the external environment, but the environment that is adjacent to the soil or to unheated or differently heated spaces. The possibilities of modeling temperatures below the object are described in the standard ČSN EN ISO 10211. This standard specifies details for a geometric model for the numerical calculation of heat flows to assess the total heat loss of buildings or parts thereof, as well as to derive linear and point heat transfer factors. Furthermore, to calculate minimum surface temperatures to assess the risk of surface condensation and to determine the surface temperature factors. These are two different computational models. Therefore, it would be appropriate to simplify these calculations by simplifying the boundary conditions, namely to conduct an isotherm at a certain level below the terrain, which will be considered as a boundary condition, which is also based on long-term experience with "frost-free" depth. This calculation would be unambiguous, clear and simple.
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Temperature field in solid fuel
Ptáček, Pavel ; Šnajdárek, Ladislav (referee) ; Pospíšil, Jiří (advisor)
The diploma thesis deals with a temperature field in a solid fuel during the combustion process. At the beginning of this thesis, research of available literature was conducted to obtain information about the composition of wood, properties affecting the combustion process, and the basics of heat transfer. Afterward, the temperature profiles of the samples were recorded during the measurement in the observation furnace. The temperature profiles of samples of six different sizes which were made of spruce and beech wood were subsequently evaluated and compared. Based on experimentally obtained data, a mathematical model was created in the OpenModellica software. Finally, the results of the mathematical model were compared with experimentally obtained data and appropriate conclusions were deduced.
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Interaction of microwave radiation with moisture in porous building materials
Paťha, Martin ; Šuhajdová, Eva (referee) ; Šuhajda, Karel (advisor)
This thesis deals with interaction of microwave radiation with wet in porous material. It examines the distribution of the temperature field, the efficiency of the method and the financial demands of the method. The most important part of this thesis was an experiment, from which all important values ??were based. The first part deals with the necessary theory and the second part is the experiment itself. The experiment was carried out for three levels of material wet. Eight samples were used for this experiment, which remained unchanged throughout the experiment. The thesis draws on previous researches that were carried out on this or similar topic.
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Heat dissipation axially-cooled glassmaking
Hovorka, Martin ; Pospíšil, Jiří (referee) ; Baláš, Marek (advisor)
The presented thesis deals with a numerical simulation of axially cooled glassmaking parison. Several types of cooling channels have been investigated according to its usage in glassmaking process. Software Star CCM+ was used to describe properties throughout the channels and also the parison itself. The main focus of this thesis lies in comparing of temperature fields, cooling effects and cooling intensity among the chosen channel designs. The boundary condi-tions were kept the same accordingly to glassmaking conditions for every design. Some out-puts were transferred to non-dimensional diagrams in order to recalculation pursuant to other boundary conditions. Properties of diffuser channel designs were compared to an experiment. Transient temperature field of the parison were calculated with Ansys APDL in order to de-termine the accumulation and stationary zone of the parison and to verify the boundary conditions for cooling channels.
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Complex strength design of condenser
Denk, Jakub ; Naď, Martin (referee) ; Lošák, Pavel (advisor)
This diploma thesis focuses on strength design of steam condenser. The goal of the thesis is to make strength calculations for the specific operation conditions, introduce possible solutions, provide recommendations and refer to weak points of such calculation procedures. First, thermal-hydraulic design in HTRI software is performed. Strength calculations respect ČSN EN 13445 standard. Strength calculation with imported temperature field is performed in ANSYS Workbench software. In the next step, another strength calculation is realized in Sant´ Ambrogio software. Results are evaluated in conclusion chapter, including recommendations for the possible following work.
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