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Zprovoznění modelu buňkového měniče v zapojení do úplného trojúhelníka
Janovec, Jiří; Kokeš, Petr; Semerád, Radko
2022 - Czech
Byl postaven a odzkoušen fyzikální model měniče MMC (Modular Multilevel Converter), který se skládá ze sériově zapojených jednotek FHB (Full H-bridge) a dalších nezbytných obvodů (pro měření, synchronizaci a předbíjení). MMC byl testován na síti nízkého napětí v konfiguraci úplného trojúhelníka s 5 buňkami v každé ze 3 větví. Měnič byl zatěžován pro symetrizaci odporové 1-fázové zátěže 3,4 kW (proud jednou větví měniče se blížil 5Aef). Výkonové buňky byly doplněny podřízenými jednotkami EPX a poté řízeny systémem TwinCat po průmyslové datové síti EtherCat. Na měniči byly testovány algoritmy řízení pro symetrizaci a kompenzaci jednofázového odběru na trojfázové síti. A laboratory model of MMC (Modular Multilevel Converter) was created and put into operation. The converter consists of series-connected FHB (Full H-bridge) cells and other necessary devices (for measurement, synchronization and pre-charging). The MMC was tested in topology of full Delta connection with 5 cells in each of 3 branches. The MMC was loaded for symmetrization of 1-phase 3.4kW resistive load (i.e. the branch current approached 5Amp rms). The power cells were completed with Slave units EPX and then controlled using TwinCat development system and EtherCat industrial data network. With the converter, control algorithms for symmetrization and compensation of 1-phase load for 3-phase power grid were tested.
Keywords:
modular multilevel converter; delta connection; full H-bridge; TwinCAT
Available at various institutes of the ASCR
Zprovoznění modelu buňkového měniče v zapojení do úplného trojúhelníka
Byl postaven a odzkoušen fyzikální model měniče MMC (Modular Multilevel Converter), který se skládá ze sériově zapojených jednotek FHB (Full H-bridge) a dalších nezbytných obvodů (pro měření, ...
Wake Behind a Cylinder: An Overview of Spatio-Temporal Aspects
Uruba, Václav
2022 - English
A circular cylinder in crossflow is subjected to the overview study from the point of view spatial and temporal characteristics. It represents itself a typical engineering problem, appearing in practice frequently in various forms. In fluid mechanics, this case is considered to be a typical canonical case, with relatively simple and straightforward definition, but complex and dynamical flow topology. The typical dynamics is characterized by quasi-periodic behavior called von Kármán – Bénard vortex street with a typical frequency expressed in dimensionless number called Strouhal number. The wake flow structure is considered to be characterized by a single frequency and 2D topology, homogeneous along the cylinder axis, very often. The presented paper concentrates on differences between this commonly accepted model and physical reality. Both temporal and spatial aspects of the flow in the wake behind a cylinder are to be addressed. The turbulent subcritical wake characterized by Reynolds number about 5 thousand will be considered, as this situation is a typical case in mechanical engineering applications.
Keywords:
circular cylinder; wake; vortex; dynamics; 3D structure
Fulltext is available at external website.
Wake Behind a Cylinder: An Overview of Spatio-Temporal Aspects
A circular cylinder in crossflow is subjected to the overview study from the point of view spatial and temporal characteristics. It represents itself a typical engineering problem, appearing in ...
TAČR TJ04000365: Projekt EDIMO
Chaloupecká, Hana; Jakubcová, Michala; Fiala, R.; Kozohorský, Jan
2022 - Czech
Zpráva popisuje postup hlavních prací na projektu TAČR TJ04000365 po celou dobu jeho řešení. Postup prací popsaný již v předešlých zprávách o projektu je shrnut jen stručně. Naopak hlouběji se zpráva zabývá validací modelu. Pro validaci byla použita data získaná fyzikálním modelováním. The report describes the work procedure on the project TACR TJ000365 for the entire duration of its solving. The work procedure, which is already described in the previous reports, is summarized in brief. In contrast, the report is engaged in the validation of the model in deep. The data acquired by the wind-tunnel modelling were utilized for the validation.
Keywords:
validation; wind tunnel; lagrangian model
Available at various institutes of the ASCR
TAČR TJ04000365: Projekt EDIMO
Zpráva popisuje postup hlavních prací na projektu TAČR TJ04000365 po celou dobu jeho řešení. Postup prací popsaný již v předešlých zprávách o projektu je shrnut jen stručně. Naopak hlouběji se zpráva ...
Aerodynamic Measurements on Transonic Compressor Blade Cascades KR-D-5 and KR-D-6
Šimurda, David; Hála, Jindřich; Luxa, Martin
2022 - English
This report contains results and evaluation of aerodynamic measurements conducted on two variant transonic compressor blade cascades with MCA profile (KR-D-5) and DCA profile (KR-D-6).
Keywords:
compressor blade cascade; experiment; transonic flow; MCA profile; DCA profile
Available at various institutes of the ASCR
Aerodynamic Measurements on Transonic Compressor Blade Cascades KR-D-5 and KR-D-6
This report contains results and evaluation of aerodynamic measurements conducted on two variant transonic compressor blade cascades with MCA profile (KR-D-5) and DCA profile (KR-D-6).
Topical Problems of Fluid Mechanics 2022
Šimurda, David; Bodnár, T.
2022 - English
Proceedings consist of papers presented during the conference Topical Problems of Fluid Mechanics 2022. \n
Keywords:
experimental fluid mechanics; mathematical modelling; CFD; turbulence; stratified fluid; multiphase flow; vortex structures; supersonic flow
Available at various institutes of the ASCR
Topical Problems of Fluid Mechanics 2022
Proceedings consist of papers presented during the conference Topical Problems of Fluid Mechanics 2022. \n
V7: Souhrnná zpráva NEMENUS pro SÚJB
Štefan, Jan; Joch, Jaroslav; Převorovský, Zdeněk; Gabriel, Dušan; Krofta, Josef; Chlada, Milan; Kober, Jan; Masák, Jan; Kunz, J.; Ashhab, B.
2022 - Czech
Toto je finální zpráva projektu TK01030108: Inovativní posuzování bezpečnosti jaderných elektráren na základě nových technologií SHM a návazných procedur - NEMENUS (NEw MEthods for NUclear Safety). Ve zprávě jsou prezentovány nejvýznamnější výsledky a výstupy projektu NEMENUS a je zde podáno souhrnné vyhodnocení přínosů ve vazbě na projektovou dokumentaci a z hlediska dlouhodobých technologických perspektiv. This is the final report of project TAČR TK01030108: Innovative methods for nuclear plant safety evaluation based on SHM technologies and related procedures - NEMENUS (NEw MEthods for NUclear Safety). In this report, the most important project results and outputs are presented, as well as a summary of its contributions with respect to long-term technological horizons.
Keywords:
structural health monitoring; nondestructive testing; fatigue testing
Available at various institutes of the ASCR
V7: Souhrnná zpráva NEMENUS pro SÚJB
Toto je finální zpráva projektu TK01030108: Inovativní posuzování bezpečnosti jaderných elektráren na základě nových technologií SHM a návazných procedur - NEMENUS (NEw MEthods for NUclear Safety). Ve ...
Use of active power filter to reduce flicker caused by electric arc furnace operation
Čerňan, Martin; Bejvl, Martin; Šimek, Petr; Valouch, Viktor
2022 - English
Effectiveness of using a parallel active power filter to compensate for the flicker of an electric arc furnace,\nand mitigate the reactive power consumption and terminal\nvoltage variation in the grid is presented and evaluated in the contribution. The model of a power system with the electric arc furnace and parallel active power filter in the frequency domain has been developed. The selected results of simulation in the frequency domain using the data collected from the 60 t EAF are presented and evaluated.
Keywords:
electric arc furnace; flicker mitigation; active power filter; power system model; simulation in frequency domain
Available at various institutes of the ASCR
Use of active power filter to reduce flicker caused by electric arc furnace operation
Effectiveness of using a parallel active power filter to compensate for the flicker of an electric arc furnace,\nand mitigate the reactive power consumption and terminal\nvoltage variation in the grid ...
V5: Zpráva o další programové spolupráci s R6 Panel
Joch, Jaroslav; Štefan, Jan
2022 - Czech
Výzkumná zpráva je závazným výstupem V5 projektu TK01030108: Inovativní posuzování bezpečnosti jaderných elektráren na základě nových technologií SHM a návazných procedur - NEMENUS (NEw MEthods for NUclear Safety). Ve zprávě je prezentován program další spolupráce s R6 Panel a s dalšími zahraničními partnery, který vznikl na základě spolupráce v rámci projektu. This report presents obligatory output V5 of project TAČR TK01030108: Innovative methods for nuclear plant safety evaluation based on SHM technologies and related procedures - NEMENUS (NEw MEthods for NUclear Safety). The report presents program of further collaboration with R6 Panel and other foreign partners established during the project.
Keywords:
structural health monitoring; nondestructive testing; fracture mechanics
Available at various institutes of the ASCR
V5: Zpráva o další programové spolupráci s R6 Panel
Výzkumná zpráva je závazným výstupem V5 projektu TK01030108: Inovativní posuzování bezpečnosti jaderných elektráren na základě nových technologií SHM a návazných procedur - NEMENUS (NEw MEthods for ...
Identification of the blade tip possition and measurement techniques using the BTT method
Maturkanič, Dušan; Procházka, Pavel; Hodboď, Robert; Mekhalfia, Mohammed Lamine
2022 - English
This paper describes the existing practice in identifying and defining the position of the blade tips and the relevant technique for measuring their vibration during rotation. In connection with the effort to precisely define the position of the vibrating blade, the paper also analysed the possibilities of unambiguous determination of its position. This work creates a parallel branch to signal processing in the complex system of precision measurement and analysis of blade vibration, which was mentioned in previous papers.
Keywords:
turbine blade; vibration; precision method; modification; harmonic function
Available at various institutes of the ASCR
Identification of the blade tip possition and measurement techniques using the BTT method
This paper describes the existing practice in identifying and defining the position of the blade tips and the relevant technique for measuring their vibration during rotation. In connection with the ...
Measurement and analysis of vibration and acoustic emissions of a railway wheel under defined dynamic excitations
Pešek, Luděk; Prasad, Chandra Shekhar; Šnábl, Pavel
2022 - English
The paper deals with experimental vibro-acoustics of railway wheel. The methodology for evaluation of effect of vibrational plate dampers was elaborated. The four variants of the wheel was measured and analyse to achieve the optimal solution of the dampers.
Keywords:
vibro-acoustics; railway wheel; dampers; noise
Available at various institutes of the ASCR
Measurement and analysis of vibration and acoustic emissions of a railway wheel under defined dynamic excitations
The paper deals with experimental vibro-acoustics of railway wheel. The methodology for evaluation of effect of vibrational plate dampers was elaborated. The four variants of the wheel was measured ...
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