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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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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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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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Turbine Housing of Turbocharger VNT with Separated Pulses in Exhaust Manifold
Polášek, Jan ; Drápal, Lubomír (referee) ; Novotný, Pavel (advisor)
This master thesis deals with the design of the turbine housing of turbocharger VNT for supplying separated pressure pulses from the exhaust manifold. Subsequently, the work includes strength analysis of the designed turbine housing. The aim of the thesis is to create components for the supply of separate pressure pulses as close as possible to the turbine. Furthermore, the modification of the existing turbine housing and the assessment of the functionality of the VNT mechanism after this modification and strength analysis. The final aim of this thesis is the creation of 2D and 3D technical documentation of newly designed and modified parts.
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Dialysis pump
Švagera, Roman ; Rudolf, Pavel (referee) ; Fialová, Simona (advisor)
Dialysis is still very important treatment process today which needs to be constantly improved. This thesis focuses on the development of a pump for dialysis units, specifically on the pressure pulsations reduction in the rotary peristaltic pump. Using experiments, the problem of peristaltic pumps is explained. With the computational modelling there are proposed design modifications leading to the pressure pulsations reduction.
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Peristaltic pump
Burda, Radim ; Fialová, Simona (referee) ; Pochylý, František (advisor)
Cílem této diplomové práce je navrhnout peristaltické čerpadlo pro hemodialýzu s ohledem na minimalizaci tlakových pulzací. Pomocí analytické analýzy je navržen nový koncept redukce tlakových pulzací, který využívá zrychlení k navýšení tlaku v prostoru mezi válečky. Fungování peristaltického čerpadla je simulováno pomocí programu Ansys Fluent pro získání lepší představy o proudění v čerpadle. Souběžně s návrhem nového konceptu bylo navrženo více tradiční čerpadlo, které bylo následně vyrobeno a experimentálně odzkoušeno. Data získaná z experimentu mohou být dále použita pro nový koncept.
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Pressure surge in the flowing gas simulation
Sedlmajer, Jakub ; Himr, Daniel (referee) ; Habán, Vladimír (advisor)
Creation of vacuum is very slow, energetically and technologicaly demanding process. Closing of valve is very simple and fast process which produces pressure surges when moving cylinder of fluid is stopped. The goal of this thesis is to find out, if it is possible to combine these processes. To reach this goal, 1D model of compressible gas flow and pressure surges in direct pipeline was made. Then follows experimental measurement evaluation and assessment of potential that the technology offers.
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CFD simulation of vortex structure in the Francis turbine draft tube at part load operating point - comparison with measurements
Neděla, Jiří ; Urban, Ondřej (referee) ; Štefan, David (advisor)
This master's thesis deals with simulation of vortex structure which is created in the draft tube of Francis turbine, at part load flow conditions. The main objective is to get the most accurate results from the calculations, using the student license of Ansys Fluent 19.1. The results from the calculations are compared with the experiment under the Francis-99 project. Mainlly in terms of dynamic properties of vortex rope – aplitude and frequency of pressure pulsations. Additionaly the time-averaged velocity profiles are compared. I used the test-case provided by NTNU – Norwegian University of Science and Technology under the Francis-99 workshop series.
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Oscillation of the compressible fluid in the cylindrical space
Smolík, Adam ; Habán, Vladimír (referee) ; Pochylý, František (advisor)
The thesis includes two main parts. The first part comprises the theoretical analysis, i.e. literary research. It has been focused on questions regarding compressive pulsation and possible damping elements. The second part focuses on the formation of mathematical model of transition of matrix gas accumulator, the hydraulic set formation by the transition matrix method, the deduction of innate and constrained values and the compressible liquid mode shapes in cylindrical space.
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