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Applications of blade vibration measurements in the laboratory of rotational laser vibrometry
Maturkanič, Dušan; Procházka, Pavel; Hodboď, Robert; Mekhalfia, Mohammed Lamine; Voronova, Evgeniya
2023 - anglický
The Laboratory of Rotational Laser Vibrometry was established at the Institute of Thermomechanics AS CR, v.v.i. in 2015 and the first experiments were started the following year. The measurements are intended for the research of vibration of rotating blades. The paper includes a summary of measurement results using a special turbine model and their consequences in theoretical research, as well as measurements with a real compressor of aircraft engine and comparison with computational analysis. The paper also describes the complex system for measurement and analysis. Klíčová slova: laboratory; turbine; blade; vibration; precision method Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Applications of blade vibration measurements in the laboratory of rotational laser vibrometry

The Laboratory of Rotational Laser Vibrometry was established at the Institute of Thermomechanics AS CR, v.v.i. in 2015 and the first experiments were started the following year. The measurements are ...

Maturkanič, Dušan; Procházka, Pavel; Hodboď, Robert; Mekhalfia, Mohammed Lamine; Voronova, Evgeniya
Ústav termomechaniky, 2023

Experimental and numerical investigation of the frequency-modal properties of the switch box
Zolotarev, Igor; Pešek, Luděk; Bula, Vítězslav; Šnábl, Pavel; Gabriel, Dušan; Mračko, Michal; Masák, Jan
2023 - anglický
The research is linked to increase of seismic resistivity of data board switch boxes. Therefore we deal with numerical modelling of the box for finding the hot spots and designing appropriate modifications. This paper deals with numerical and experimental frequency-modal properties of the switch box and mutual comparison for numerical model validation. Klíčová slova: modal analysis; natural frequencies; eigen-modes of vibration Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Experimental and numerical investigation of the frequency-modal properties of the switch box

The research is linked to increase of seismic resistivity of data board switch boxes. Therefore we deal with numerical modelling of the box for finding the hot spots and designing appropriate ...

Zolotarev, Igor; Pešek, Luděk; Bula, Vítězslav; Šnábl, Pavel; Gabriel, Dušan; Mračko, Michal; Masák, Jan
Ústav termomechaniky, 2023

Calibrated finite volume method-based simulation framework for laser shock peening
Isoz, Martin; Gruber, Pavel; Schmidt, Jaroslav; Kubíčková, Lucie; Štefan, Jan; Kaufman, Jan; Brajer, Jan; Gabriel, Dušan
2023 - anglický
Modern and highly competitive industry seeks components with high strength and fatigue resistance. Both of these properties may be improved by peening of the component surface and the standard peening processes, such as the shot peening, are widely used in both automotive and aerospace industries. The laser shock\npeening (LSP), i.e. hardening of the material surface by a laser-induced shock wave, is a modern alternative to the standard peening. Concurrently, the industrial applications of LSP are promoted by recently emerged affordable high power-density lasers. However, the nascent LSP applications are still mostly a trial-and-error\nprocesses based on an extensive experimental testing. Consequently, we focused on a highly application-driven development of a framework for LSP modeling, and the internal workings and results of which are the focus of the present contribution. Klíčová slova: laser shock peening; modeling; finite volume method; OpenFOAM Dokument je dostupný na externích webových stránkách.
Calibrated finite volume method-based simulation framework for laser shock peening

Modern and highly competitive industry seeks components with high strength and fatigue resistance. Both of these properties may be improved by peening of the component surface and the standard peening ...

Isoz, Martin; Gruber, Pavel; Schmidt, Jaroslav; Kubíčková, Lucie; Štefan, Jan; Kaufman, Jan; Brajer, Jan; Gabriel, Dušan
Ústav termomechaniky, 2023

Mixing characteristics of a magnetically driven Rushton turbine in an unbaffled stirred tank reactor
Idžakovičová, Kristýna; Haidl, Jan; Gebouský, Ondřej; Isoz, Martin
2023 - anglický
The standard and well-researched stirred vessel configuration comprises a tank equipped with one or more impellers positioned in the vessel’s axis and multiple wall-mounted baffles preventing the central vortex creation. However, particular industries, such as biotechnology, have an increased need for a sterile environment that often results in the usage of atypical stirred vessel configurations. An example of a commonly equipped atypical stirred vessel is an unbaffled stirred tank with an eccentric magnetically driven impeller. However, there is only a little knowledge about the mixing characteristics of such designs. In this work, we list experimental results for both the standard and atypical stirred vessel configurations. Furthermore, we present a CFD model of the atypical configuration. The model is used to calculate its mixing characteristics that are subsequently compared against our experimental results. It is shown that for the liquid height (H) to the vessel diameter (T) ratio H/T ≲ 1.2, the characteristics of both the standard and atypical designs coincide. For higher liquid heights (i) the characteristics of the atypical design decrease dramatically, and (ii) the characteristics estimates based on approaches developed for the standard configuration become unreliable. Klíčová slova: stirred vessel; eccentric impeller; unbaffled tank; CFD; OpenFOAM; experiment Dokument je dostupný na externích webových stránkách.
Mixing characteristics of a magnetically driven Rushton turbine in an unbaffled stirred tank reactor

The standard and well-researched stirred vessel configuration comprises a tank equipped with one or more impellers positioned in the vessel’s axis and multiple wall-mounted baffles preventing the ...

Idžakovičová, Kristýna; Haidl, Jan; Gebouský, Ondřej; Isoz, Martin
Ústav termomechaniky, 2023

Engineering Mechanics 2023
Radolf, Vojtěch; Zolotarev, Igor
2023 - anglický
The proceedings contains papers presented at the 29th International Conference on Engineering Mechanics, which has been held in OREA Resort Devět Skal in Czech Republic under auspices of the Czech Society of Mechanics and being a part of IFTOMM (The International Federation for the Promotion of Mechanism and Machine Science) activities. As it corresponds with character of the conference, this proceedings consists of several topic oriented parts: Biomechanics, Fluid mechanics, Dynamics, Fracture mechanics, Mechatronics, Reliability of structures, Mechanics of solids, Technological processes, Thermodynamics. The volume represents a well-balanced overview of theoretical, numerical and experimental work on fundamental and applied studies. Klíčová slova: biomechanics; dynamics; mechatronics; fluid mechanics; mechanics of solids; fracture mechanics Dokument je dostupný na externích webových stránkách.
Engineering Mechanics 2023

The proceedings contains papers presented at the 29th International Conference on Engineering Mechanics, which has been held in OREA Resort Devět Skal in Czech Republic under auspices of the Czech ...

Radolf, Vojtěch; Zolotarev, Igor
Ústav termomechaniky, 2023

Přehledná dokumentace vrubů vyrobených technologií laserového vypalování do potrubních těles v rámci projektu TK01030108 (NEMENUS)
Štefan, Jan
2023 - český
Tato technická zpráva byla zpracována v rámci projektu DP_04_02_04: Výzkum aplikovatelnosti moderních SHM (Structural Health Monitoring) systémů pro zvýšení spolehlivosti a ekonomičnosti provozu jaderných elektráren (stávajících, nových i malých modulárních reaktorů). Účel této zprávy spočívá v přehledné dokumentaci zkušeností s technologií laserového vypalování, která byla v letech 2020 až 2022 úspěšně aplikována v rámci předchozího projektu TAČR TK01030108 (projekt NEMENUS) pro výrobu vrubů do potrubních zkušebních těles, a která může být dle předpokladů s výhodou využita také v experimentálním programu stávajícího projektu. Informace shromážděné v tomto dokumentu napomohou při specifikaci zadání poskytovateli této služby (spol. ATG, s. r. o.), a při optimalizaci parametrů laseru pro daný účel. This technical report has been prepared within the project DP_04_02_04: Research of applicability of modern SHM (Structural Health Monitoring) systems for increasing reliability and economic efficiency of nuclear power plant operation (existing, new and small modular reactors). The purpose of this report is to provide an overview documentation of the experience with laser technology, which has been successfully applied in the previous TAČR project TK01030108 (NEMENUS project, 2020 and 2022) for the production of notches into pipe test specimens, and which is expected to be advantageously used also in the experimental program of the current project. The information gathered in this document will help in the specification of the assignment to the provider of this service (ATG, s.r.o.), and in the optimization of the laser parameters for the purpose. Klíčová slova: material testing; high-cycle fatigue; laser technology Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Přehledná dokumentace vrubů vyrobených technologií laserového vypalování do potrubních těles v rámci projektu TK01030108 (NEMENUS)

Tato technická zpráva byla zpracována v rámci projektu DP_04_02_04: Výzkum aplikovatelnosti moderních SHM (Structural Health Monitoring) systémů pro zvýšení spolehlivosti a ekonomičnosti provozu ...

Štefan, Jan
Ústav termomechaniky, 2023

Measurements on Turbine Cascade KOBRA
Luxa, Martin; Hála, Jindřich; Šimurda, David
2023 - anglický
The report contains results and evaluation of aerodynamic measurement on a blade cascade representing the section imitating the conical stream line in the last rotor row of a gas trubine under considerable off-design condition. The research report contains detailed specifications of the measured model, overview of the results of the optical measurements (interferometry, schlieren method in Toepler configuration) and pneumatic measurements (traversing with five hole conical probe downstream the cascade). Klíčová slova: turbine cascade; turbine off-design condition; tarnsonic flow Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Measurements on Turbine Cascade KOBRA

The report contains results and evaluation of aerodynamic measurement on a blade cascade representing the section imitating the conical stream line in the last rotor row of a gas trubine under ...

Luxa, Martin; Hála, Jindřich; Šimurda, David
Ústav termomechaniky, 2023

Autonomous vehicles lane detection using particle filters
Věchet, Stanislav; Krejsa, Jiří; Chen, K.S.
2022 - anglický
Lane detection belongs among many others crucial tasks which an autonomous vehicles traveling in urban roads need to take care of. We present a lane detection method which uses particle filters combined with visual information from onboard camera to control the vehicles direction. Our initial experiments shows promising results as applied and tested in urban roads with focus on real-time data processing. Klíčová slova: mobile robot; signal processing; measurement Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Autonomous vehicles lane detection using particle filters

Lane detection belongs among many others crucial tasks which an autonomous vehicles traveling in urban roads need to take care of. We present a lane detection method which uses particle filters ...

Věchet, Stanislav; Krejsa, Jiří; Chen, K.S.
Ústav termomechaniky, 2022

Mobile Robot in the Elevator: What Floor Am i On?
Krejsa, Jiří; Věchet, Stanislav; Chen, K.S.; Havelka, M.; Černil, M.
2022 - anglický
Wheeled mobile robots in multiple stories buildings have to use elevator to access arbitrary floor of the building. To do so, the control system must be able to detect and access elevator controls and also determine on which floor the elevator stopped. The paper deals with the latter problem, using the fusion of relative floor change detected by onboard accelerometer and absolute floor number detected by the processing of elevator information screen panel image acquired by onboard camera. Bayesian filter is used for data fusion and convolution neural network for image processing. Field tests resulted in 97% correct detection. Klíčová slova: mobile robot; elevator floor determination; Bayesian filtering Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Mobile Robot in the Elevator: What Floor Am i On?

Wheeled mobile robots in multiple stories buildings have to use elevator to access arbitrary floor of the building. To do so, the control system must be able to detect and access elevator controls and ...

Krejsa, Jiří; Věchet, Stanislav; Chen, K.S.; Havelka, M.; Černil, M.
Ústav termomechaniky, 2022

Vysokonapěťový pulzní zdroj a řídící jednotka
Gruber, Jan; Janovec, Jiří; Šonský, Jiří; Němec, Tomáš
2022 - český
Zpráva obsahuje popis sestavy vysokonapěťového pulzního zdroje (PPSU) a řídící jednotky (SPCU), které jsou využívány v kombinaci s výbojovou komorou a párem elektrod k aerosolové syntéze nanomateriálů. Uvedena jsou schémata zapojení, seznam elektronických i mechanických součástek, jakožto i popis konektorů a zřetězeného propojení více soustav. Zpráva rovněž obsahuje informace o referenčních parametrech výbojů a popis komunikačního protokolu včetně nastavitelných proměnných. The report contains description of Pulsed Power Source Unit (PPSU) and Spark Control Unit (SPCU), which are utilized in combination with Spark Discharge Chamber and pair of electrodes for aerosol synthesis of nanomaterials. The report includes electronic schematics, list of components, description of connectors and way to chain-link and operate more sets of units. The report also includes information about discharge reference parameters and description of communication protocol and its variables. Klíčová slova: electrotechnics; high-voltage; power transformation; pulse generators Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Vysokonapěťový pulzní zdroj a řídící jednotka

Zpráva obsahuje popis sestavy vysokonapěťového pulzního zdroje (PPSU) a řídící jednotky (SPCU), které jsou využívány v kombinaci s výbojovou komorou a párem elektrod k aerosolové syntéze ...

Gruber, Jan; Janovec, Jiří; Šonský, Jiří; Němec, Tomáš
Ústav termomechaniky, 2022

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