No (3139)
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3139
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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
2024 - English
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.
Keywords:
natural frequencies; FEM; LDV; strain gauge
Available at various institutes of the ASCR
Computational and experimental assessment of natural frequencies in a bladed disk system
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 ...
Flow simulations approach for flocculation tanks
Idžakovičová, Kristýna; Bílek, V.; Haidl, J.; Isoz, Martin; Pivokonský, M.
2024 - English
Flocculation in water treatment facilities plays a key role in the separation of colloidal inorganic and organic substances. Its optimization leads to a significant increase in its efficiency and savings of operational costs. However, it is currently based on trial-and-error experimental approaches. In this contribution, we focus on flow modeling in stirred flocculation tanks that would, after coupling with a calibrated model of particle aggregation, enable simulationbased flocculation optimization. Despite the abundance of literature on stirred tank modeling, there is no universal agreement on the methodology used to describe turbulence nor on the approach to the computational mesh creation. Consequently, there is no unified methodology for simulations and their validation. To address this, we present a best-practice methodology for economical, yet reliable flow simulations in the said device. This methodology includes the choice of the turbulence model, the approach to the design of a high quality mesh suitable for arbitrary geometries, and results evaluation. It is developed based on an extensive literature review, a multitude of flow simulations using several meshes of progressively higher quality and resolution, and various strategies to converge to steady-state flow conditions. The simulation quality indicators used here involve comparison with the experimental data on fluid velocity, stirrer power output, and flow rate through the impeller zone. Additionally, the resulting flow simulation models are compared using tracer transport simulations, hinting at their potential for coupling with particle aggregation models.
Keywords:
flocculation tank; stirring; MRF; CFD; OpenFOAM
Available at various institutes of the ASCR
Flow simulations approach for flocculation tanks
Flocculation in water treatment facilities plays a key role in the separation of colloidal inorganic and organic substances. Its optimization leads to a significant increase in its efficiency and ...
Verification of the dynamic properties of a new model turbine wheel with free blades
Voronova, Evgeniya; Procházka, Pavel; Maturkanič, Dušan; Mekhalfia, Mohammed Lamine; Hodboď, Robert
2024 - English
The paper describes a new experimental model of turbine wheel with free blades. Verification tests were carried out using a Doppler laser vibrometer, with a focus on the equipment parameters under various conditions. The measurements were performed in the Laboratory of Rotational Laser Vibrometry originated at the Institute of Thermomechanics AS CR, v.v.i.
Keywords:
natural frequencies; vibration; blade; laser; turbine
Available at various institutes of the ASCR
Verification of the dynamic properties of a new model turbine wheel with free blades
The paper describes a new experimental model of turbine wheel with free blades. Verification tests were carried out using a Doppler laser vibrometer, with a focus on the equipment parameters under ...
Modification of cooling system for laboratory measurement of rotor blade vibration
Maturkanič, Dušan; Procházka, Pavel; Hodboď, Robert; Voronova, Evgeniya; Mekhalfia, Mohammed Lamine
2024 - English
Last year, the replacement of the turbine wheel model was completed in the Laboratory of Rotational Laser Vibrometry of the Institute of Thermomechanics AS CR, v.v.i. Based on previous experience and the expected higher operating load planned for the new wheel, the cooling system was modified at the same time. The paper describes the main effort in this direction and the results that clarify the previous damage of the measuring device.
Keywords:
blade; vibration; cooling system; measurement; laboratory
Available at various institutes of the ASCR
Modification of cooling system for laboratory measurement of rotor blade vibration
Last year, the replacement of the turbine wheel model was completed in the Laboratory of Rotational Laser Vibrometry of the Institute of Thermomechanics AS CR, v.v.i. Based on previous experience and ...
DYNAMICS OF MACHINES AND MECHANICAL SYSTEMS WITH INTERACTIONS : PROCEEDINGS DYMAMESI 2024
Zolotarev, Igor; Pešek, Luděk; Kozień, M. S.
2024 - English
The aim of the DYMAMESI is to facilitate the exchange of up to date information and knowledge among specialists in structural and multibody dynamics, in coupled interacting systems as aero-elasticity, hydro-elasticity, biomechanics, systems with feedbacks and mechatronics. In 2023 will be hosted by Cracow University of Technology, Institute of Applied Mechanics, Section of Dynamics of Systems.
Keywords:
dynamics; vibrations of mechanical systems; vibrodiagnostics; energy transformations
Available at various institutes of the ASCR
DYNAMICS OF MACHINES AND MECHANICAL SYSTEMS WITH INTERACTIONS : PROCEEDINGS DYMAMESI 2024
The aim of the DYMAMESI is to facilitate the exchange of up to date information and knowledge among specialists in structural and multibody dynamics, in coupled interacting systems as aero-elasticity, ...
Design analysis of the heat exchanger between the primary and the intermediate circuits of the small modular reactor DAVID
Kobylka, D.; Hrubý, Jan; Kordík, Jozef; Gabriel, Dušan; Marek, René; Isoz, Martin
2023 - Czech
The report summarizes the joint results of the Department of Nuclear Reactors FNSPE, CTU and IT CAS, in the area of thermal and hydraulic calculations of the heat exchanger between the primary and intermediate circuits of the developed small modular reactor (SMR) DAVID. The assignment parameters were further specified during control days and with updated documentation. During the analysis of the initial system parameters, it was found that the original geometric configuration of the exchanger had a completely insufficient surface for heat transfer. A decision was made, several parameters were modified and based on a series of calculations using two independent simplified models, a reasonable configuration with a significantly smaller diameter of the tubes in a significantly larger number was chosen. The pressure losses on both sides of the heat exchanger are within normal ranges and will not cause problems with the construction of these circuits. Although there are differences between the results from both used models, their comparison shows that the chosen different calculation methods lead to approximately the same results and the models do not show fundamental errors.
Keywords:
small modular reactor DAVID; thermodynamics; heat exchanger
Available at various institutes of the ASCR
Design analysis of the heat exchanger between the primary and the intermediate circuits of the small modular reactor DAVID
The report summarizes the joint results of the Department of Nuclear Reactors FNSPE, CTU and IT CAS, in the area of thermal and hydraulic calculations of the heat exchanger between the primary and ...
Assessment of a report evaluating the impact analysis of the EDU II reactor unit power increase on the vertical stability and dynamic response of the internal parts of the reactor, including consideration of the LOCA DN500 event
Pták, Svatopluk
2023 - Czech
This technical report summarizes the results of the assessment aimed at evaluation of the impact analysis of the increase in the performance of EDU II units in connection with the project '6729 - Use of design margins of the Dukovany reactor units' on the vertical stability and dynamic response of the reactor internal components, including consideration of the LOCA DN500 event, specifically, it is an assessment of two reports of author collectives from ÚJV, a. s.: M. Klemenc and P. Gál: 'Analyzes of the impact of the power increase on the dynamic behavior of RIC during the LOCA DN500 event, report ÚJV DITI 2301/1242, 12/2020 and M. Švrček a J. Vyčichl: 'Analyzes of the impact of increasing power on vertical stability and vibration response (high-cycle fatigue) of RIC', report ÚJV DITI 2301/1307, 08/2021. Tato technická zpráva shrnuje výsledky posouzení výpočtové dokumentace zaměřené na hodnocení analýzy dopadu zvýšení výkonu bloků EDU II v souvislosti s projektem '6729 − Využití projektových rezerv bloků EDU II' na vertikální stabilitu a dynamickou odezvu vnitřních částí reaktoru včetně uvažování nehody LOCA DN500, konkrétně se jedná o posouzení dvou zpráv autorských kolektivů z ÚJV, a. s.: 'M. Klemenc a P. Gál: Analýzy dopadu zvýšení výkonu na dynamické chování VČR při nehodě LOCA DN500, zpráva ÚJV DITI 2301/1242, 12/2020' a M. Švrček a J. Vyčichl: Analýzy dopadu zvýšení výkonu na vertikální stabilitu a vibrační odezvu (vysokocyklovou únavu) VČR, zpráva ÚJV DITI 2301/1307, 08/2021.
Keywords:
loss coolant accident; dynamic response; primary pipelime of nuclear reactor; internal parts of nuclear reactor
Available at various institutes of the ASCR
Assessment of a report evaluating the impact analysis of the EDU II reactor unit power increase on the vertical stability and dynamic response of the internal parts of the reactor, including consideration of the LOCA DN500 event
This technical report summarizes the results of the assessment aimed at evaluation of the impact analysis of the increase in the performance of EDU II units in connection with the project '6729 - Use ...
Contract summary report OZM-LCF-2023: Experimental evaluation of low cycle fatigue properties of steel 1.4529
Štefan, Jan; Parma, Slavomír
2023 - Czech
This technical report was prepared within the framework of the contract "OZM-LCF-2023: Experimental evaluation of the properties of steel 1.4529 in terms of low cycle fatigue". The report clearly documents all relevant information concerning the technical performance of the contract, starting from the design of the experimental program, through the protocols of the experiments performed, to the summary evaluation of the program, including proposals for possible contract extension and follow-up experimental activities. Tato technická zpráva byla zpracována v rámci zakázky „OZM-LCF-2023: Experimentální hodnocení vlastností oceli 1.4529 z hlediska nízkocyklové únavy“. Ve zprávě jsou přehledně zdokumentovány všechny podstatné informace týkající se odborného plnění zakázky počínaje návrhem experimentálního programu, přes protokoly o provedených experimentech až po souhrnné vyhodnocení programu vč. návrhů pro případné rozšíření zakázky a navazující experimentální činnost.
Keywords:
material testing; low-cycle fatigue; austenitic stainless steels
Available at various institutes of the ASCR
Contract summary report OZM-LCF-2023: Experimental evaluation of low cycle fatigue properties of steel 1.4529
This technical report was prepared within the framework of the contract "OZM-LCF-2023: Experimental evaluation of the properties of steel 1.4529 in terms of low cycle fatigue". The report clearly ...
Measurements on KR-D-11B Optimized Subsonic Blade Cascade
Šimurda, David; Hála, Jindřich
2023 - English
This report contains results and evaluation of aerodynamic measurements conducted on a subsonic compressor blade cascade.
Keywords:
compressor blade cascade; experiment; subsonic flow; optimized profile
Available at various institutes of the ASCR
Measurements on KR-D-11B Optimized Subsonic Blade Cascade
This report contains results and evaluation of aerodynamic measurements conducted on a subsonic compressor blade cascade.
Dynamics of Machines and Mechanical Systems with Interactions, DYMAMESI 2023
Zolotarev, Igor; Pešek, Luděk; Kozień, M. S.
2023 - English
The aim of the DYMAMESI is to facilitate the exchange of up to date information and knowledge among specialists in structural and multibody dynamics, in coupled interacting systems as aero-elasticity, hydro-elasticity, biomechanics, systems with feedbacks and mechatronics. The colloquium DYMAMESI 2021 is cofunded by the Strategy AV21 initiative of the Czech Academy of Sciences of the Czech Republic, and in 2021 will be hosted by Cracow University of Technology, Institute of Applied Mechanics, Section of Dynamics of Systems.
Keywords:
dynamics; vibrations of mechanical systems; vibrodiagnostics; energy transformations
Available at various institutes of the ASCR
Dynamics of Machines and Mechanical Systems with Interactions, DYMAMESI 2023
The aim of the DYMAMESI is to facilitate the exchange of up to date information and knowledge among specialists in structural and multibody dynamics, in coupled interacting systems as aero-elasticity, ...
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