|
|
The Pump with a Diffuser with Stochastic Blades (Runner and Diffuser)
Dobšáková, Lenka ; Melichar, Jan (referee) ; Veselý, Jindřich (referee) ; Haluza, Miloslav (advisor)
This doctoral thesis studies the non-uniform blade cascade for centrifugal pumps. Influence of non-uniform blade cascade is investigated on the impeller and diffuser. A non-uniform blading impeller of pumps in this doctoral thesis was examined in terms of influence on efficiency characteristic. The idea of using non-uniform blading is to obtain a flat efficiency characteristic. Then the centrifugal pump could be used on larger scale of power with achieving a sufficiently high efficiency. The work is based on experimental measurements and numerical simulations of non-uniform hydraulic pump components. Non-uniform impeller and the diffuser were newly designed for this research. A new measuring track of small submersible pumps was needed to design and build for measurements. Different pump combinations with conventional hydraulics on one working point and hydraulics with non-uniform were measured. All measurements were evaluated and characteristics of efficiency, head and power were obtained for each measured combination. Some of pump combinations (which were measured in experiment) were numerically simulated by program Ansys Fluent. Data needed to evaluate the characteristic of efficiency and specific energy were collected from each numerical simulation. A theoretical consideration concerns the influence of non-uniform blade cascade applied on diffuser. The suggestion how to decrease hydraulic losses in canals was done. The theoretical consideration how to make a flat efficiency characteristic was made.
|
|
|
The pump with a diffuser with stochastic blades (runner and diffuser)
Dobšáková, Lenka ; Haluza, Miloslav (advisor)
This doctoral thesis studies the non-uniform blade cascade for centrifugal pumps. Influence of non-uniform blade cascade is investigated on the impeller and diffuser. A non-uniform blading impeller of pumps in this doctoral thesis was examined in terms of influence on efficiency characteristic. The idea of using non-uniform blading is to obtain a flat efficiency characteristic. Then the centrifugal pump could be used on larger scale of power with achieving a sufficiently high efficiency. The work is based on experimental measurements and numerical simulations of non-uniform hydraulic pump components. Non-uniform impeller and the diffuser were newly designed for this research. A new measuring track of small submersible pumps was needed to design and build for measurements. Different pump combinations with conventional hydraulics on one working point and hydraulics with non-uniform were measured. All measurements were evaluated and characteristics of efficiency, head and power were obtained for each measured combination. Some of pump combinations (which were measured in experiment) were numerically simulated by program Ansys Fluent. Data needed to evaluate the characteristic of efficiency and specific energy were collected from each numerical simulation. A theoretical consideration concerns the influence of non-uniform blade cascade applied on diffuser. The suggestion how to decrease hydraulic losses in canals was done. The theoretical consideration how to make a flat efficiency characteristic was made.
|
|
|
Analysis of current lead joints inside HV current transformers
Pálka, Marek ; Váňo, Pavel (referee) ; Drápela, Jiří (advisor)
The main focus of the dissertation thesis is determine the size of the fastening screw connection and fastening torque of the connection, which will be applied during assembly of the instrument current transformers and sensors. The large part of thesis is an experimental measurement of the proposed configurations of connections and modelling (simulating) certain model of connections in Ansys and SolidWorks analysis programs. The result of the dissertation will be design of tightening of the connection according to transient resistance and thermal losses.
|
|
|
Electrodynamic forces acting on moving contact of electrical apparatus
Šic, Pavel ; Valenta, Jiří (referee) ; Bušov, Bohuslav (advisor)
This master’s thesis is focused on calculation, simulation and experimental verification of electrodynamic forces acting upon movable contact piece of MCCB and experimental current carrying path. A short description of low voltage circuit breakers is briefly discussed in first chapter. Second chapter is focused upon contact system analysis of particular MCCB with thermomagnetic trigger. A hardness of contact materials is briefly described. A detailed analytical calculations were used to determine electrodynamic forces in MCCB. A FEM simulation in ANSYS Maxwell was carried out for comparison with analytical results. An experimental apparatus was designed and built for verification of constriction repulsion force, so called Holm’s force. A series of measurements is subsequently performed on proposed apparatus and results are compared with results from previous chapters.
|
|
|
GSM-EDGE and UMTS Systems Coexistence
Gleissner, Filip ; Hanus, Stanislav (advisor)
The dissertation thesis deals with the investigation of the coexistence of GSM–EDGE and UMTS systems with focus on the physical layer of the systems. The aim is to provide a set of recommendations for practical cooperation while the systems operate in both the separated and the common radio bands. A detailed description of signal processing of both the systems on the physical layer is presented. On the basis of this description, models of both systems were created and implemented in the MATLAB environment. The simulations are focused on the physical layer quality parameters, especially the bit error ratio evaluation for various ratios of useful signal power to noise power during the transmission over the radio channel. Simulation is also used to examine the quality of received useful signal while it is interfered by signals from the same and adjacent channels. The purpose is to determine the isolation between these adjacent channels, when the bit error ratio of the useful signal does not exceed a certain reference value. The simulation results are subsequently subjected to comparison with the results of the experimental measurements in laboratory conditions. Before the measurements are carried out, a study of possible interference types is performed. Consequently, the crucial parameters of the measuring equipment used are verified. From the results of simulations and measurements, the proposal of a minimum and recommended carrier separation between both the systems is presented in order to efficiently utilize the assigned frequency spectrum. Furthermore, for the cooperation in both the separated and the common radio bands, the necessary precautions are given for reaching the required isolation and thereby inter-system interference minimization.
|
|
|
Measurements on Turbine Cascade
Vondra, Marek ; Pospíšil, Jiří (referee) ; Fiedler, Jan (advisor)
The Aim of this Diploma thesis is the measurement on turbine cascade. The first part is focused on measurement of the flow characteristics of the turbine cascade using a three–hole pressure probe. The second part includes the blade profile pressure measurement. Both measurements are performed both experimentally and by computer simulation in Ansys and the results are compared. Part of the work is also file containining the computer simulation, which was carried out in CFX program.
|
|
| |
|
|
Model of an up-to-date commercial laundry premise
Tůma, Zdeněk ; Kšenzuliak, Vladimír (referee) ; Pavlas, Martin (advisor)
The thesis deals with a design of an up-to-date commercial laundry with focus on equipments applied. The proces is studied and analysed throughly first. Important aspects for choice of equipments are mentioned (i.e. steam, power and natural gas consumptions. These informations are summarized from data sheets provided by manufacturers as well as from experimental measurements in existing facilities.
|
|
|
The application of renewable energy in buildings
Panovec, Jan ; Formánek, Marian (referee) ; Hirš, Jiří (advisor)
The aim of this diploma thesis is to understand the functioning of heating and cooling systems in an administrative building built in passive standard using a renewable energy source. The thesis includes theoretical findings of heat pumps and designing the heating systems. The experimental part contains an analysis of working of heating and cooling systems in selected rooms in assigned building, which includes an experimental measurement of selected quantities and a thermographic measurement. In the last part of the thesis a comparison of measured and simulated values using simulation software was done.
|
|
| |
guest ::
