Time-variable normal contact force influence on dry-friction damping of self-excited vibration of bladed turbine wheel

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61388998%3A_____%2F21%3A00549725" target="_blank" >RIV/61388998:_____/21:00549725 - isvavai.cz</a>

Výsledek na webu

<a href="http://repozytorium.p.lodz.pl/handle/11652/4116" target="_blank" >http://repozytorium.p.lodz.pl/handle/11652/4116</a>

DOI - Digital Object Identifier

—

Jazyk výsledku

angličtina

Název v původním jazyce

Time-variable normal contact force influence on dry-friction damping of self-excited vibration of bladed turbine wheel

Popis výsledku v původním jazyce

Recently [1-2], the new calculation approach based on modal synthesis method is proposed for evaluation of structural and dry-friction damping effect on self-excited vibrations due to aeroelasticninstability in the bladed turbine wheels. Due to the modal reduction, the calculations are made computationally very efficient. The method will be herein used to study a dry-friction damping ofnself-excited vibration of an industrial turbine wheel with 66 blades. The aerodynamic excitation arises from the spatially periodical flow of steam through the stator blade cascade. The self-excited aeroelastic forces of blades are described by Van der Pol model [3]. For evaluation of damping effect, the blade tie-boss couplings are applied on this particular turbine wheel. Therefore, neighboring blades are interconnected by rigid arms that are on one side fixed to one blade and are in friction contact ontheir free side with the other blade. The contact point pairs of two neighboring blades overlap in undeformed state of the cascade and static normal contact forces are prescribed. The relative contactdisplacements due to blade cascade deformation are calculated from kinematics of relative blade motions. Due to relative normal motions in contacts, the prescribed contact forces will vary in timeduring vibration. In the contribution, the effect of variable magnitude of normal contact forces with respect to the angle of contact surfaces on the wheel dynamics and on level of friction damping will be analyzed. Friction forces in contacts are driven by the modified Coulomb friction law. The analysis will be oriented on the narrow frequency range and on the case when a slip motion is prevailing in the contacts.

Název v anglickém jazyce

Time-variable normal contact force influence on dry-friction damping of self-excited vibration of bladed turbine wheel

Popis výsledku anglicky

Recently [1-2], the new calculation approach based on modal synthesis method is proposed for evaluation of structural and dry-friction damping effect on self-excited vibrations due to aeroelasticninstability in the bladed turbine wheels. Due to the modal reduction, the calculations are made computationally very efficient. The method will be herein used to study a dry-friction damping ofnself-excited vibration of an industrial turbine wheel with 66 blades. The aerodynamic excitation arises from the spatially periodical flow of steam through the stator blade cascade. The self-excited aeroelastic forces of blades are described by Van der Pol model [3]. For evaluation of damping effect, the blade tie-boss couplings are applied on this particular turbine wheel. Therefore, neighboring blades are interconnected by rigid arms that are on one side fixed to one blade and are in friction contact ontheir free side with the other blade. The contact point pairs of two neighboring blades overlap in undeformed state of the cascade and static normal contact forces are prescribed. The relative contactdisplacements due to blade cascade deformation are calculated from kinematics of relative blade motions. Due to relative normal motions in contacts, the prescribed contact forces will vary in timeduring vibration. In the contribution, the effect of variable magnitude of normal contact forces with respect to the angle of contact surfaces on the wheel dynamics and on level of friction damping will be analyzed. Friction forces in contacts are driven by the modified Coulomb friction law. The analysis will be oriented on the narrow frequency range and on the case when a slip motion is prevailing in the contacts.

Druh

O - Ostatní výsledky

CEP obor

—

OECD FORD obor

20302 - Applied mechanics

Projekt

<a href="/cs/project/GA20-26779S" target="_blank" >GA20-26779S: Výzkum nestabilit dynamického stall flutteru a jejich následků na aplikace turbostrojů pomocí matematických, numerických a experimentálních metod</a><br>

Návaznosti

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

Rok uplatnění

2021

Kód důvěrnosti údajů

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