Damping of flutter oscillations by dry friction contacts

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61388998%3A_____%2F18%3A00495845" target="_blank" >RIV/61388998:_____/18:00495845 - isvavai.cz</a>

Výsledek na webu

—

DOI - Digital Object Identifier

—

Jazyk výsledku

angličtina

Název v původním jazyce

Damping of flutter oscillations by dry friction contacts

Popis výsledku v původním jazyce

Self-excited flutter vibrations of turbine blades are very dangerous phenomena for the service life of turbines. The various design treatments are therefore applied for suppression of blades’ flutter vibrations. The in-troduction of dry friction elements is one of the very effective methods.nThe dynamic behavior of a computational model of 30-blades turbine wheel is investigated in this paper. Due to the narrow frequency range, the blades can be modelled as systems with one degree of freedom and the blades cascade has then 30 eigen-frequencies. The blades in the rotating blades cascade are excited by aerodynamic forces arising from the spatially periodical flow of steam through the stator blades cascade. This flow produces both forced vibration and self-excited vibrations of blades – flutter. The simple Van der Pol models of excitation aero-elastic forces, acting on individual blades are considered. The possibility of application of dry friction elements on reduction or even on full elimination of these dangerous vibrations will be presented on several examples. It was shown that the dry friction forces needed for suppression of dangerous flutter vibrations strongly depends on the complexity of modes and they are inversely proportional to the number of nodal diameters in modes of vibrations.n

Název v anglickém jazyce

Damping of flutter oscillations by dry friction contacts

Popis výsledku anglicky

Self-excited flutter vibrations of turbine blades are very dangerous phenomena for the service life of turbines. The various design treatments are therefore applied for suppression of blades’ flutter vibrations. The in-troduction of dry friction elements is one of the very effective methods.nThe dynamic behavior of a computational model of 30-blades turbine wheel is investigated in this paper. Due to the narrow frequency range, the blades can be modelled as systems with one degree of freedom and the blades cascade has then 30 eigen-frequencies. The blades in the rotating blades cascade are excited by aerodynamic forces arising from the spatially periodical flow of steam through the stator blades cascade. This flow produces both forced vibration and self-excited vibrations of blades – flutter. The simple Van der Pol models of excitation aero-elastic forces, acting on individual blades are considered. The possibility of application of dry friction elements on reduction or even on full elimination of these dangerous vibrations will be presented on several examples. It was shown that the dry friction forces needed for suppression of dangerous flutter vibrations strongly depends on the complexity of modes and they are inversely proportional to the number of nodal diameters in modes of vibrations.n

Druh

O - Ostatní výsledky

CEP obor

—

OECD FORD obor

20302 - Applied mechanics

Projekt

<a href="/cs/project/GA16-04546S" target="_blank" >GA16-04546S: Aeroelastické vazby a dynamické chování rotačně periodických těles</a><br>

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2018

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů