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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 - anglický
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.
Klíčová slova:
natural frequencies; FEM; LDV; strain gauge
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
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 ...
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 - anglický
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.
Klíčová slova:
natural frequencies; vibration; blade; laser; turbine
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
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 - anglický
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.
Klíčová slova:
blade; vibration; cooling system; measurement; laboratory
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
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 - anglický
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.
Klíčová slova:
dynamics; vibrations of mechanical systems; vibrodiagnostics; energy transformations
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
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, ...
Optical and Pneumatic Measurements on TR-U-11 Cascade
Luxa, Martin; Hála, Jindřich; Šimurda, David
2023 - anglický
The report contains results and evaluation of conducted optical (interferometry and schlieren technique) and pneumatic measurements on the first variant of the new tip section, intended for turbine rotor blade.
Klíčová slova:
transonic flow; rotor turbine blade; tip section
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Optical and Pneumatic Measurements on TR-U-11 Cascade
The report contains results and evaluation of conducted optical (interferometry and schlieren technique) and pneumatic measurements on the first variant of the new tip section, intended for turbine ...
Dynamics of Machines and Mechanical Systems with Interactions, DYMAMESI 2023
Zolotarev, Igor; Pešek, Luděk; Kozień, M. S.
2023 - anglický
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.
Klíčová slova:
dynamics; vibrations of mechanical systems; vibrodiagnostics; energy transformations
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
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, ...
Závěrečná zpráva o řešení projektu MPO čís. CZ.01.1.02/0.0/0.0ú20_321/0023673
Zolotarev, Igor; Pešek, Luděk; Gabriel, Dušan; Procházka, Pavel P.
2023 - český
Projektu MPO s názvem Vývoj rozvaděče pro těžké podmínky a snížení rizik ohrožení kritické infrastruktury byl zaměřen na výzkum, vývoj optimalizované konstrukce a zajištění konfigurační technologie pro opakovanou produkci různých variant modulárního systémového rozváděče pro použití v těžkých podmínkách a snížení rizik seizmického ohrožení, pro zajištění spolehlivosti kritické infrastruktury. Výstupem má být prototyp seizmicky robustního zařízení s dynamicky odlehčené konstrukce, vysokou spolehlivostí funkce sestavy rozvaděče a elektrovýzbroje a SW aplikace pro interaktivní návrhy a dokumentaci. The MIT project entitled Development of a switchgear for severe conditions and reduction of risks of critical infrastructure threat was focused on research, development of optimized design and provision of configuration technology for repeated production of different variants of modular system switchgear for use in severe conditions and reduction of risks of seismic threat, to ensure the reliability of critical infrastructure. The output is to be a prototype seismically robust device with a dynamically lightweight design, high reliability of switchgear and electrical equipment assembly function, and a software application for interactive design and documentation.
Klíčová slova:
vibration; natural frequencies; modes of vibration; seismic resistance; dynamic properties of structures
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Závěrečná zpráva o řešení projektu MPO čís. CZ.01.1.02/0.0/0.0ú20_321/0023673
Projektu MPO s názvem Vývoj rozvaděče pro těžké podmínky a snížení rizik ohrožení kritické infrastruktury byl zaměřen na výzkum, vývoj optimalizované konstrukce a zajištění konfigurační technologie ...
Simulating particle-laden flows: from immersed boundaries towards model order reduction
Isoz, Martin; Kubíčková, Lucie; Kotouč Šourek, M.; Studeník, Ondřej; Kovárnová, A.
2023 - anglický
Particle-laden flow is prevalent both in nature and in industry. Its appearance ranges from the trans-port of riverbed sediments towards the magma flow, from the deposition of catalytic material inside particulate matter filters in automotive exhaust gas aftertreatment towards the slurry transport in dredging operations. In this contribution, we focus on the particle-resolved direct numerical simulation (PR-DNS) of the particle-laden flow. Such a simulation combines the standard Eulerian approach to computational fluid dynamics (CFD) with inclusion of particles via a variant of the immersed boundary method (IBM) and tracking of the particles movement using a discrete element method (DEM). Provided the used DEM allows for collisions of arbitrarily shaped particles, PR-DNS is based (almost) entirely on first principles, and as such it is a truly high-fidelity model. The downside of PR-DNS is its immense computational cost. In this work, we focus on three possibilities of alleviating the computational cost of PR-DNS: (i) replacing PR-DNS by PR-LES or PR-RANS, while the latter requires combining IBM with wall functions, (ii) improving efficiency of DEM contact solution via adaptively refined virtual mesh, and (iii) developing a method of model order reduction specifically tailored to PR-DNS of particle-laden flows.
Klíčová slova:
particle-laden flow; CFD-DEM; arbitrarily-shaped particles; finite volume method
Dokument je dostupný na externích webových stránkách.
Simulating particle-laden flows: from immersed boundaries towards model order reduction
Particle-laden flow is prevalent both in nature and in industry. Its appearance ranges from the trans-port of riverbed sediments towards the magma flow, from the deposition of catalytic material ...
On Reynolds-averaged turbulence modeling with immersed boundary method
Kubíčková, Lucie; Isoz, Martin
2023 - anglický
The immersed boundary (IB) method is an approach in the computational fluid dynamics in which complex geometry conforming meshes are replaced by simple ones and the true simulated geometry is projected onto the simple mesh by a scalar field and adjustment of governing equations. Such an approach is particularly advantageous in topology optimizations (TO) where it allows for substantial speed-up since a single mesh can be used for all the tested topologies. In our previous work, we linked our custom IB variant, the hybrid fictitious domain-immersed boundary method (HFDIB), with a TO framework and successfully carried out an optimization under laminar flow conditions. However, to allow for optimizations of reallife components, the IB approach needs to be coupled with an affordable turbulence modeling. In this contribution, we focus on extending the HFDIB approach by the possibility to perform Reynolds-averaged simulations (RAS). In particular, we implemented the k − ω turbulence model and wall functions for closure variables and velocity.
Klíčová slova:
immersed boundary; RAS; wall functions; CFD; OpenFOAM
Dokument je dostupný na externích webových stránkách.
On Reynolds-averaged turbulence modeling with immersed boundary method
The immersed boundary (IB) method is an approach in the computational fluid dynamics in which complex geometry conforming meshes are replaced by simple ones and the true simulated geometry is ...
Finite element modal analysis of a silicone vocal fold filled with fluid
Hájek, P.; Radolf, Vojtěch; Horáček, Jaromír; Švec, J. G.
2023 - anglický
A three dimensional (3D) finite element (FE) model of a silicone vocal fold (VF) filled with fluid is presented here. The silicone part of the model is based on partial differential equations of the continuum mechanics and consider large deformations. The fluid domain encapsulated in the silicone VF is defined semianalytically as a lumped-element model describing the fluid in hydrostatic conditions. The elongated and pressurized silicone VF was subjected to perturbed modal analysis. Results showed that the choice of the fluid inside the VF substantially influences the natural frequencies. Namely, the water-filling lowers the natural frequencies approximately by half over the air-filling. Besides, the procedure of reverse engineering for obtaining the geometry of the VF from already 3D-printed mold is introduced.
Klíčová slova:
perturbed modal analysis; finite element method; vocal folds; reverse engineering; biomechanics of voice
Dokument je dostupný na externích webových stránkách.
Finite element modal analysis of a silicone vocal fold filled with fluid
A three dimensional (3D) finite element (FE) model of a silicone vocal fold (VF) filled with fluid is presented here. The silicone part of the model is based on partial differential equations of the ...
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