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Computational and experimental assessment of natural frequencies in a bladed disk system
Mekhalfia, Mohammed Lamine ; Procházka, Pavel ; Maturkanič, Dušan ; Voronova, Evgeniya ; Hodboď, Robert
This paper examines the modal characteristics of a bladed disk in rotating machinery systems using a combination of analytical and experimental modal analysis methods. The analysis involves measuring natural frequencies and mode shapes under different operational conditions. A comparative analysis is conducted to assess modal properties obtained from both analytical and experimental approaches, while also considering the influence of rotation speed. Additionally, Finite Element Method (FEM) outputs are used to accurately position the strain gauge. Integrating these techniques provides a comprehensive understanding of the bladed disk's behaviour under varying rotational speeds, enhancing result accuracy and facilitating thorough investigation within rotating machinery systems.
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Numerical and Experimental Investigation of the Flow Field in Five Blade Linear Cascade in Subsonic Flow
Šnábl, Pavel ; Chindada, Sony ; Bublík, O. ; Procházka, Pavel P. ; Prasad, Chandra Shekhar
In large steam turbines, last stage blades are very long and must be designed very thin and with no shroud to minimize the centrifugal force which leads to low eigenfrequencies and low structural damping. In this case, aero-elastic damping plays important role on last stage bladed disc’s dynamics. Three major aero-elastic issues found in turbomachinery are forced response, non-synchronous vibrations, and flutter. Flutter is an unstable, self-excited vibration resulting from coupling between the structural vibrations and unsteady aerodynamic forces. It is clear that this unstable behaviour must be avoided and predictions of flutter behaviour need to be performed during design stage of the turbine.\n
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Statistical Approach for BTT probes distribution
Mekhalfia, Mohammed Lamine ; Procházka, Pavel ; Šmíd, R. ; Tchawou Tchuisseu, Eder Batista
Blade tip timing (BTT) system is a non-invasive method used for measuring the blade tip timing of rotating machinery. The BTT system typically consists of sensor probes, signal conditioning system, and data acquisition unit. The sensor probes are placed in proximity to the rotating blade tips, Sensors measure the time at which each blade passes by the probe. By measuring the blade tip timing, the BTT system can detect changes in the blade tip vibration, which is an important for the health monitoring and performance optimization of rotating machinery [1]. To ensure accurate measurement of blade tip timing, the probe arrangement is crucial. The placement of the probe relative to the blade tips can affect the measurement accuracy, and thus, several arrangement algorithms have been developed to optimize the placement of the probes. Instead of considering the condition number, a statistical algorithms is followed to optimize the placement of probes for accurate measurement of blade tip timing in turbo-machinery. The statistical approach will be employed to determine the optimal locations for probes, with the aim of reducing errors in the measurement of blade tip timing. \n
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Design inverter using semiconductor on based SiC
Kharchenko, Vadym ; Procházka, Petr (referee) ; Kuzdas, Jan (advisor)
This work builds on a semester project 2. from the winter semester of this academic year. The aim of this thesis is the design of converter using semiconductor components based on SiC technology. This converter is used in the construction of quick charger for electric vehicles. The design of this converter must be based on the requirements for compliance voltage safety. It describes the design of power components used in the construction of this facility, the determination of their losses and determines the overall efficiency of the converter. There is also proposed mathematical model of high-frequency transformer and made his simulation in Matlab-Simulink.
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Car-battery charger
Kadlec, Josef ; Procházka, Petr (referee) ; Červinka, Dalibor (advisor)
This bachelor’s thesis is considered by projection and construction of the car battery charger with switching source. One-pulsed conducting changer is base of this charger. The charger is intended for accumulators of nominate voltage 6 and 12V. Accumulators are charged by method of constant voltage with current limitation of 0.5A, 5A, 20A and 50A. Value 50A has reason during stating of car for example in winter, because the charger helps to battery. The device is equipped with additional protection, which protects the charger and also the accumulator and the supply network. Three pilot lights are the next equipment of the device.
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Manufacturing of pin with flange
Procházka, Pavel ; Řiháček, Jan (referee) ; Podaný, Kamil (advisor)
The bachelor thesis is focused on the design of the towing hitch, which is used in the tractor. The component will be the production of a die forging technology made of low-alloy steel 13 242. The material is supplied as hot-rolled bars with a diameter of 60 mm and a length of 6 000 mm. The size of the production series has been set at 25,000 pieces per year. Due to the issue and the size of the forging, the component will be made on a power hammer. The machine Šmeral KHZ 8A, appears to be a suitable machine as the forging work was calculated at 89 kJ. The technical - economic evaluation takes into account material costs, which amount to 1,364,271 CZK. The die is made of tool steel 19 663, its purchase price is 73 000 CZK.
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Electric drive of lift model with EC motor
Kutrucz, Tomáš ; Procházka, Petr (referee) ; Koláčný, Josef (advisor)
This diploma thesis describes a simulator of home elevator driven by an EC engine (external combustion engine). The introductory chapter of the thesis deals with the history of elevators. It also contains the description of EC engines, the description of the construction of the simulator and of the mechanical, electrical, and software adjustments carried out as based on the thesis. The main part of the work concentrates on the description of the changes of the drive algorithms, the production of the 3D simulator and the animation in the background of 3D Solid Works. Moreover, it also deals with the experimental performance measurement based on the loading of the stimulator drive.
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Power supply module for servo-drive
Kudláček, Pavel ; Procházka, Petr (referee) ; Červinka, Dalibor (advisor)
The aim of the diploma thesis is to theoretically design and to put the mains power supply module for two-axis servo amplifier TZG 560 with the total power 28kW for the company TG Drives into practice. The analytical design of the power part with the braking circuit, the calculation of power components’ heat balance, EMI filter design and realization of measuring, controlling and indication circuits are described in the thesis. In addition, the mechanical device construction, structure of the controlling program and the results obtained in the verification process of the module functionality are presented.
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