Řada strojní. 2010, roč. 56 / Mechanical Series. 2010, vol. 56

Permanent URI for this collectionhttp://hdl.handle.net/10084/111975

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Now showing 1 - 20 out of 96 results

Thermodynamics of combustion gases from LPG propane-butane
(Vysoká škola báňská - Technická univerzita Ostrava, 2010) Vitázek, Ivan; Havelka, Juraj
Liquefied LPG is a mixture of good quality hydrocarbons, propane and butane without inert gases. In their paper the authors would like to present the methodology for derivation of all necessary thermodynamic parameters of combustion gases of LPG and relations for modelling and control evaluation of LPG combustion in a specific appliance. Two computer programs in Q-Basic have been made to carry out these calculations.
Determination of the heat transfer coefficient by the inversion method
(Vysoká škola báňská - Technická univerzita Ostrava, 2010) Vaculík, Miroslav; Velička, Marek; Burda, Jiří
The surface of a blank, cast on the continuous casting equipment, is cooled by water nozzles. The intensity of heat dissipation for individual nozzles cannot be practically determined directly on the casting machine therefore it is investigated on a laboratory model of the Department of Thermal Engineering. A physical quantity that characterizes transport of heat from a surface is the heat transfer coefficient whose size depends on several operational parameters. This contribution describes determination of the heat transfer coefficient on a hot physical model. An inversion method, based on the measuring of heat gradient between two thermocouples placed on the body of a hot probe, has been used for the calculation.
Decomposition methods for a PIV data analysis with application to a boundary layer separation dynamics
(Vysoká škola báňská - Technická univerzita Ostrava, 2010) Uruba, Václav
Separation of the turbulent boundary layer (BL) on a flat plate under adverse pressure gradient was studied experimentally using Time-Resolved PIV technique. The results of spatio-temporal analysis of flow-field in the separation zone are presented. For this purpose, the POD (Proper Orthogonal Decomposition) and its extension BOD (Bi-Orthogonal Decomposition) techniques are applied as well as dynamical approach based on POPs (Principal Oscillation Patterns) method. The study contributes to understanding physical mechanisms of a boundary layer separation process. The acquired information could be used to improve strategies of a boundary layer separation control.
Modeling of flow in nuclear reactor fuel cell outlet
(Vysoká škola báňská - Technická univerzita Ostrava, 2010) Urban, František; Kučák, Ľubor; Muškát, Peter; Bereznai, Jozef
Safe and effective load of nuclear reactor fuel cells demands qualitative and quantitative analysis of relations between coolant temperature in fuel cell outlet temperature measured by thermocouple and middle temperature of coolant in thermocouple plane position. In laboratory at Insitute of thermal power engineering of the Slovak University of Technology in Bratislava was installed an experimental physical fuel cell model of VVER 440 nuclear power plant with V 213 nuclear reactors. Objective of measurements on physical model was temperature and velocity profiles analysis in the fuel cell outlet. In this paper the measured temperature and velocity profiles are compared with the results of CFD simulation of fuel cell physical model coolant flow.
The influence of chemical composition of steels on the numerical simulation of a continuesly cast of billet
(Vysoká škola báňská - Technická univerzita Ostrava, 2010) Štětina, Josef; Kavička, František; Mauder, Tomáš
The chemical composition of steels has significant influence on the actual concasting process, and on the accuracy of its numerical simulation and optimization. The chemical composition of steel affects the thermophysical properties (heat conductivity, specific heat capacity and density in the solid and liquid states) often requires more time than the actual numerical calculation of the temperature fields of a continuously cast steel billet. Therefore, an analysis study of these thermophysical properties was conducted. The order of importance within the actual process and the accuracy of simulation were also determined. The order of significance of the chemical composition on thermophysical properties was determined with respect to the metallurgical length. The analysis was performed by means of a so-called calculation experiment, i.e. by means of the original numerical concasting model developed by the authors of this paper. It is convenient to conduct such an analysis in order to facilitate the simulation of each individual case of concasting, thus enhancing the process of optimization.
Verification of methodology for determination of deposit thickness on heat transfer surface of natural gas coolers
(Vysoká škola báňská - Technická univerzita Ostrava, 2010) Příhoda, Miroslav; Čarnogurská, Mária; Molínek, Jiří; Pyszko, René
The paper describes briefly an original methodology for the determination of the deposit thickness on the inside heat transfer surface of natural gas cooler and a procedure of its verification at the cooler CH_R of the booster station KS01 in Velké Kapušany. The methodology is based on the measurement of the degree of the gas cooling. It has the universal validity and can be used to determine the thickness of the deposits of all types of coolers working on any booster station.
Experimental research of cavitation in channels of very small scales
(Vysoká škola báňská - Technická univerzita Ostrava, 2010) Olšiak, Róbert; Mlkvik, Marek
This paper deals with defining of experimental methods and with description of an experimental setup used in research of fluid flows in jets and other orifices of very small scales. The jet used in the experiments has an axissymetric shape with circular cross-section. The experimental setup used for experiments consists of these basic parts: a device used for microscopic visualization and capturing of image of the liquid flow in small scale channels, a digital image data acquisition system and a system of image data manipulation, a system for parallel acquisition and manipulation with other experimental data.
Numerical modelling of emission formation in domestic boiler for coal
(Vysoká škola báňská - Technická univerzita Ostrava, 2010) Nosek, Radovan; Jandačka, Jozef; Szlek, Andrzej
The aim of the work is to develop a method of simple characterization of solid fuels combustion in fixed bed, which would be useful for CFD modelling. In this work, the measurements were performed in a test rig, where a combustion front propagates against the airflow. Concentrations of flue gas species were registered at the exit of a fixed bed reactor and the temperature of burning coal was measured in selected points of the reactor as functions of time.
Nonlinear mathematical programming in engineering applications
(Vysoká škola báňská - Technická univerzita Ostrava, 2010) Mauder, Tomáš
This paper deals with suitable nonlinear optimization in engineering applications via mathematical programming. This tool is used for optimization and control of production of steel slabs and inverse tasks, such as determination of boundary conditions. Mathematical models contain 2D Fourier-Kirchhoff equation including boundary conditions. Presence of phase and structural changes is covered by enthalpy approach. The software implementation was executed as a link between MATLAB and modeling language GAMS.
Influence of heat radiation on a temperature sensor in a measuring chamber
(Vysoká škola báňská - Technická univerzita Ostrava, 2010) Mareš, Radim
Temperature in a chamber for measuring surface tension of metastable supercooled water by the elevation method is detected by resistance temperature sensors. Two copper blocks of different temperatures placed on two opposite sides of the measuring chamber serve as heat accumulators. This paper deals with the influence of heat radiation of the copper blocks on the sensor depending on its position in the chamber.
Experimental study of aerosol deposition in a realistic lung model
(Vysoká škola báňská - Technická univerzita Ostrava, 2010) Lízal, František; Elcner, Jakub; Jedelský, Jan; Jícha, Miroslav
The inhalation route for administration of medicaments is becoming more and more popular in recent years. The reason is non-invasiveness of the method and instantaneous absorption of drugs to the blood circulation. It is necessary to deliver exact amount of drug to the specific segment because of occurrence of diverse diseases in different segments of lungs. The aim of our work is to contribute to better understanding of transport and deposition of aerosolized drugs in lungs and hence to more effective treatment of respiratory diseases due to the targeted drug delivery. We provided measurements of aerosol deposition in segmented realistic model of lungs without a mouth cavity. Monodisperse particles marked with fluorescein were supplied to the model. The model was then disassembled to segments and each segment was rinsed with isopropanol, whereby fluorescent samples were created. Each sample was analysed by fluorometer and an amount of aerosol deposited in the segment was calculated. Experiences obtained by this study were used for creation of a new model with the mouth cavity. This model will be used for future studies with porous and fiber aerosols.
Temperature field progression in annular tube around heated rod in respect to the mass flow of coolant
(Vysoká škola báňská - Technická univerzita Ostrava, 2010) Lávička, David
The paper looks into liquid flow simulation in the annular tube around the heated rod. The numerical simulation serves primarily the purpose of describing the temperature field in the annular tube that represents a simplified model of a nuclear reactor fuel rod. The fuel rod model uses several configurations of spacers which affect the flow of coolant - water - in the annular flow channel. For selected variants of spacers, temperature fields have been mutually compared in respect to various mass flow characteristics of the coolant.
Study of raw materials treatment by melting and gasification process in plasma arc reactor
(Vysoká škola báňská - Technická univerzita Ostrava, 2010) Kurilla, Peter
The world consumption of metals and energy has increased in last few decades and it is still increasing. Total volume production results to higher waste production. Raw material basis of majority metals and fossil fuels for energy production is more complex and current waste treatment has long term tendency. Spent power cells of different types have been unneeded and usually they are classified as dangerous waste. This important issue is the main topic of the thesis, in which author describes pyrometallurgical method for storage batteries – power cells and catalysts treatment. During the process there were tested a trial of spent NiMH, Li – ion power cells and spent copper catalysts with metal content treatment by melting and gasification process in plasma arc reactor. The synthetic gas produced from gasification process has been treated by cogenerations micro turbines units for energy recovery. The metal and slag from treatment process are produced into two separately phases and they were analyzing continually.
Numerical simulation of flow in the annular tube
(Vysoká škola báňská - Technická univerzita Ostrava, 2010) Kovařík, Petr
This paper looks into numerical simulation of flow and heat transfer in the annular tube. For various values of inlet velocities are specified values of heat transfer in the annular tube and along the full length of the heated tube. The effect of various simplified spacer geometries on heat transfer in the annular tube is also monitored.
Description and application of the CE-SE scheme
(Vysoká škola báňská - Technická univerzita Ostrava, 2010) Kosík, Martin; Fürst, Jiří
The CE-SE scheme is new numerical methodology for conservation laws. It was developed by Dr.Chang of NASA Glenn Research Center and his collaborators. The 1D and 2D variant of CE-SE scheme for scalar convection and for Euler equations for incompressible flows is described. The CE-SE scheme is compared with classical schemes in 1D. The solution to inviscid incompressible flow in GAMM channel in 2D is presented.
Modeling and simulation of flow over a wavy surface
(Vysoká škola báňská - Technická univerzita Ostrava, 2010) Knotek, Stanislav; Jícha, Miroslav
This paper presents an analytical method for calculating the physical characteristics of laminar flow using the theory of Orr-Sommerfeld equation. The assembled linear model is one of the approaches applied to the problem of gas flow over a wavy surface. Assumptions and results are compared with simulations results obtained using CFD software StarCCM+.
The importance of thermophysical properties of steels for the numerical simulation of a concasting process
(Vysoká škola báňská - Technická univerzita Ostrava, 2010) Kavička, František; Štětina, Josef; Sekanina, Bohumil; Mauder, Tomáš
The thermophysical properties of steels have significant influence on the actual concasting process, and on the accuracy of its numerical simulation and optimization. The determination of these properties (heat conductivity, specific heat capacity and density in the solid and liquid states) often requires more time than the actual numerical calculation of the temperature fields of a continuously cast steel billet, cylinder or slab (generally a concasting). The influence of individual properties should be neither under- nor over-estimated. Therefore, an analysis/parametric study of these thermophysical properties was conducted. The order of importance within the actual process and the accuracy of simulation and optimization were also determined. Individual properties, which, in some cases, were obtained from tables, and in others experimentally, were substituted by an approximation using orthogonal polynomials. The accuracy of each polynomial is dependent on the precision of individual values. The order of significance of individual thermophysical properties was determined with respect to the metallurgical length. The analysis was performed by means of a so-called calculation experiment, i.e. by means of the original and universal numerical concasting model developed by the authors of this paper. It is convenient to conduct such an analysis in order to facilitate the simulation of each individual case of concasting, thus enhancing the process of optimization.
1D simulation of heat transfer in cable channel
(Vysoká škola báňská - Technická univerzita Ostrava, 2010) Hejčík, Jiří; Jícha, Miroslav
The paper deals with the use of 1D simulation tool AMESim to predict the steady state temperatures of a high-voltage electrical cables which are installed inside a cable channel.
1D software tools for simulations of indoor cabin environment
(Vysoká škola báňská - Technická univerzita Ostrava, 2010) Fišer, Jan; Jícha, Miroslav; Pokorný, Jan
Numerical simulation of air flow in realistic model of human upper airways
(Vysoká škola báňská - Technická univerzita Ostrava, 2010) Elcner, Jakub; Lízal, František; Forman, Matěj; Jícha, Miroslav
This article deals with CFD calculations of flow patterns in a realistic model of the upper respiratory tract. RANS method was used for the calculation. The flow was solved as an unsteady one due to its nature. Two breathing cycles were simulated, 15 l/min which corresponds to the idle breathing mode and 30 l/min which corresponds to light activity. The model of upper airways consists of the oral cavity, larynx and trachea, which branches up to the fourth generation. Values of the velocity field distribution calculated are the basis for future calculations of aerosol transport and deposition in the human respiratory tract.

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