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Dynamic properties of tuned branch
Čepl, Ondřej ; Kůrečka, Jan (referee) ; Habán, Vladimír (advisor)
The main part of the thesis is experimental determination of transmission in side-branch resonator. In first part are described basics of digital signal processing and sound damping in piping systems. A special attention is payed to Fourier transform. The second part deals with experimental measurement of damping in a side-branch resonator for several lengths of the resonator. The collected data were analyzed using Fourier transform with a fulfilled coherence condition. At the end of this section are shown graphs, which describe tuning frequency dependence of side-branch resonator's length. There are seven different lengths. The thesis contains comparison of theoretical and measured tuning frequencies.
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Study of plunger pump with linear motor
Machát, Pavel ; Habán, Vladimír (referee) ; Pochylý, František (advisor)
The aim of this thesis is an engineering design of plunger pump with linear motor. This type of pump is used especially for blood pumping in heart surgery. The theoretical part is focused on distribution of pumps, description of extracorporeal circuit and booster heart history. There are basic calculations derived, which describe plunger pump performance. Then varied designs of plunger pumps follows, which are differed in size, shape and application. Next part includes design of reverse valves and their CFD computation.
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Characteristics of gels used in the fluids engineering
Hudák, Igor ; Habán, Vladimír (referee) ; Fialová, Simona (advisor)
Not only in common life, but also in the technical area the usage of gels presents some kind of standard. Gels offer a unique possibility of usage in numerous areas. The gel structure itself is a very interesting material however it’s hard to specify its characteristics. The gel system presents a huge macromolecular network which enables to observe its different characteristics in comparison to other materials. In some circumstances gels act almost as conventional materials, in other circumstances, however, they act significantly otherwise. Therefore this bachelor thesis deals with a description and summarization of single characteristics of gels in chosen branches of the mechanical engineering industry where gels are used on a daily basis, such as sealant of pipeline systems, wires or electronic components. The thesis also describes principles of gel formation, with the emphasis to building of gel substance and with respect to its mechanical and physical features. In the end, the thesis gives a comparison of chosen characteristics of gels that are used as sealants and gels that are used for encapsulation of electrical set.
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Modulated ultrasonic water jet cutting – optimization of the liquid wave guide shape
Veselý, Radek ; Foldyna, Josef (referee) ; Habán, Vladimír (advisor)
High speed water jets have un-substitutable place in unconventional technologies in the machining of materials. Indeed its larger spreading is limited above all by its really high purchase price and also high costs of the operation. Certain possibility is represented by high-speed pulsating jets, which don’t put such a high pretension on arrangement of generating the pressure during the comparable operation. Probably the most effective method of the generating of pulsating water jets is ultrasonic modulation. This work could benefit to understanding spreading of pressure impulses between ultrasonic generator and output nozzle. Pulsating is solved by the numerical calculation using transfer matrix method.
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The influence of decreasing of impeller diameter, change Q - Y characteristic
Hyriak, Maroš ; Habán, Vladimír (referee) ; Haluza, Miloslav (advisor)
The purpose of the thesis is to familiarize with the fundamental characteristics of ta centrifugal pump while changing geometry of the output section of its impeller trimming. Characteristics of a pump is calculated whilst diameter of the impeller is changed. More specifically, changes in the flow and energy are observed while diameter of the impeller is decreasing. Two possible solutions, approximate and accurate, are offered for both parameters. The thesis suggests that an application of the approximate solution is satisfactory for the flow calculation of the impeller. In contrast, for the energy calculation is the approximate solution sufficient only in case of the slight trimming. Increase in the trimming results in the drop of the hydraulic efficiency and decrease in the accuracy of the results. Consequently, the accurate solution is recommended for the energy calculations. Limitations of the paper may be represented by two facts. First, in comparison with the calculations, results are in reality affected my numerous variables that have not been included in the calculations due to their unpredictability. Second, calculations were based on the several assumptions that are rarely met in the reality. The results of the thesis are applicable in the every-day life when adapting the pump to the customer needs.
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The influence of the impeller diameter decreasing on the pumps characteristic
Jelen, Richard ; Haluza, Miloslav (referee) ; Habán, Vladimír (advisor)
This master’s thesis deals with changing the geometry of the output section of the impeller of the radial centrifugal pumps and its influence on the characteristics of the pump. In engineering practice for these radial centrifugal pumps it is possible to change the parameters based on the requirements. This adaptation of parameters is called impeller trimming. Impeller trimming means the reduction of the impeller diameter thereby decreasing the flow, head and efficiency. Existing equations for calculating the changes in the characteristics of the impeller trimming are inaccurate. In this thesis is describes a possible method of putting for the recalculation characteristics of a pump based on the impeller diameter on the available characteristics of pumps.
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Computation of compression force on surface
Stejskal, Jiří ; Habán, Vladimír (referee) ; Čermák, Libor (advisor)
In technical computing we often need to find the resulting load on surface caused by the compression force. The aim of this thesis is to suggest one of the possible approaches to do so if the surface is given explicitly or by the coordinates of some of it's points. In the first section, the mathematical definition of the surface with some of it's important properties is mentioned. There is a basic theory of Bézier surfaces, which form the main part of this thesis in the second part. Further on, some results from the theory of surface integrals are mentioned. The last section describes the whole algorithm of computing the resulting load together with the MATLAB program which is added to this thesis. Three examples are given at the end.
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Machine diagnostics based on models
Kapusta, Juraj ; Habán, Vladimír (referee) ; Huzlík, Rostislav (advisor)
The main idea is focused on the diagnostics of a specific hydraulic system, i.e. sensing the physical quantities of the hydraulic circuit with a tank and a centrifugal pump driven by an asynchronous motor. It is a system of pipes connected to the pump, where due to its work it creates a water flow and a pressure increase. In practice, this issue is also addressed in the energy and nuclear industries. Primary circuits in some cases cannot be designed or modified to be able measure locally the pressure value. It is necessary to measure this quantity indirectly - from the motor currents. The main idea of the work is to diagnose the system by an indirect method - specifically to detect the state of the hydraulic circuit (pressure, flow) from the values that we are able to measure and detect damage in advance. In the second part of the thesis is the application of the parts of a specific hydraulic system in the simulation environment MATLAB Simulink. The model of the hydraulic circuit contains mathematical-physical relations that simulate the course of the mentioned experiment. The results of the simulation are compared with the results of the experiment. The model also investigates the simulation of a fault condition, when we supply pressure pulsations to the hydraulic circuit. It is these changes in the hydraulic part that affect the characteristics of the pump and the asynchronous motor, so we are able to diagnose this system.
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Description unsteady operating conditions of siphon swirl turbine
Krejčiřík, Stanislav ; Habán, Vladimír (referee) ; Hudec, Martin (advisor)
The master´s thesis focuses on the behavior of the siphon turbine during unsteady flow. There are two possible conditions. The first condition involves commissioning the turbine. In this situation turbine works like a pump. In the second case, it includes shutting down the turbine by aerating the siphon and thereby breaking the water column. This thesis deals with the second case, where the results of the experiment and the mathematical model are compared.
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Monitoring of hydraulic machines using acoustic emissions
Závorka, Dalibor ; Pochylý, František (referee) ; Habán, Vladimír (advisor)
The goal of this diploma thesis is to clarify possibilities of usage of acoustic emission as a hydraulic machinery diagnostics tool. Especially for exposing presence of ruptures or cracks in the parts of machine, assuming changes in acoustic exposure of the part during operation. This clarification is based on series of simple measured experiments, which consist of monitoring the bolt placed in fluid stream inside of a pipe. This bolt was preloaded against inner wall of pipe by appropriate tightening torque. This preload is supposed to simulate effects of the size of rupture. High preload simulates small rupture or none in object and respectively small preload is supposed to simulate big rupture. A group of pressure sensors and accelerometers measures experiments and their evaluations are processed by script created in software MATLAB. Outputs of this script are charts with effective values of respective sensors from the entire record split into individual frequency spectrums. These charts compare spectrums of each configuration to judge effects of parameters changes.
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