A parametric study of Limit Cycle Oscillation of a bladed disk caused by flutter and friction at the blade root joints

Lassalle, Marco; Firrone, Christian Maria

doi:10.1016/j.jfluidstructs.2017.10.004

Cited by 16 publications

(6 citation statements)

References 33 publications

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“…Some of these methods are based on frequency approach like the Harmonic Balance Method (HBM) [17,18]. Decoupled approaches have allowed to find Limit Cycle Oscillations (LCO) of the structure by using the HBM procedure, while modelling aerodynamic effects from Computational Fluid Dynamics (CFD) calculations [19,20]. More recently, a fully coupled method in the frequency domain has been established [21] in order to find LCO by using harmonic formulation in both flow and structure models, and iterating in a fixed point loop between the two physics.…”

Section: Introductionmentioning

confidence: 99%

Investigation of a Methodology for Describing Fan Blade Flutter Limitations Induced by Non-Linear Friction at Blade Roots

Ombret¹,

Pret²,

Dugeai³

et al. 2021

Proceedings of the 8th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering (COM

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Fan Blade Flutter is an aeroelastic instability which may occur during the operation of a jet engine, depending on the working conditions of the fan stage. It finds its origins in some various mechanisms, including the impact of the environment of the fan stage, which may play an important role in the stability limits due to acoustic effects. If not properly taken into account, flutter can lead to an anticipated ruin of the fan stage as the fluid keeps on giving energy to the structure. However, nonlinear phenomena may appear at some high vibratory amplitude of the blades, resulting in energy dissipation of the aeroelastic system. Blade roots friction is an example of such a case : by dry-friction dissipation at blade roots, a limitation of the vibratory amplitude may be reached, the so-called Limit Cycle Oscillations (LCO), within the unstable regions of the operating domain predicted with a usual linear structural modelling. By taking these nonlinear effects into account, it is then possible to define more precisely the stability limits of the fan stage. In this paper, we describe a methodology to predict LCO induced by blade roots friction, including acoustic effects on stability. First, assuming a linear behaviour of the structure, the stability limits of the fan stage are described using the cyclic symmetry hypothesis and Computational Fluid Dynamics (CFD). Acoustics effects are taken into account by including the fan inlet environment in the numerical model. Then, a nonlinear structural model of the blade is used to compute nonlinear complex modes in order to check for the presence of a LCO. To do so, a reduced model of the fluid response to the blade movement is used. To sum up, this work intends to establish a methodology to be used in an industrial context for the analysis of the nonlinear stability of the fan stage, including LCO phenomena. COMPDYN 2021 8 th ECCOMAS Thematic Conference on Computational Methods in Structural Dynamics and Earthquake Engineering M. Papadrakakis, M. Fragiadakis (eds.

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Section: Introductionmentioning

confidence: 99%

Investigation of a Methodology for Describing Fan Blade Flutter Limitations Induced by Non-Linear Friction at Blade Roots

Ombret¹,

Pret²,

Dugeai³

et al. 2021

Proceedings of the 8th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering (COM

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“…This work focusses on nonlinear contact forces. In the steady state, flutter-induced vibrations typically take the form of a periodic oscillation, denoted as Limit Cycle Oscillation (LCO) [7,8]. This is also the case when multiple modes of vibration are aeroelastically unstable [8].…”

Section: Introductionmentioning

confidence: 99%

Development of a Fully-Coupled Harmonic Balance Method and a Refined Energy Method for the Computation of Flutter-Induced Limit Cycle Oscillations of Bladed Disks with Nonlinear Friction Contacts

Berthold¹,

Gross²,

Frey³

et al. 2021

Preprint

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Flutter stability is a dominant design constraint of modern gas and steam turbines. To further increase the feasible design space, flutter-tolerant designs are currently explored, which may undergo Limit Cycle Oscillations (LCOs) of acceptable, yet not vanishing, level. Bounded self-excited oscillations are a priori a nonlinear phenomenon, and can thus only be explained by nonlinear interactions such as dry stick-slip friction in mechanical joints. The currently available simulation methods for blade flutter account for nonlinear interactions, at most, in only one domain, the structure or the fluid, and assume the behavior in the other domain as linear. In this work, we develop a fully-coupled nonlinear frequency domain method which is capable of resolving nonlinear flow and structural effects. We demonstrate the computational performance of this method for a state-of-the-art aeroelastic model of a shrouded turbine blade row. Besides simulating limit cycles, we predict, for the first time, the phenomenon of nonlinear instability, i.e. , a situation where the equilibrium point is locally stable, but for sufficiently strong perturbation (caused e.g. by an impact), the dry frictional dissipation cannot bound the flutter vibrations. This implies that linearized theory does not necessary lead to a conservative design of turbine blades. We show that this phenomenon is due to the nonlinear contact interactions at the tip shrouds, which cause a change of the vibrational deflection shape and frequency, which in turn leads to a loss of aeroelastic stability. Finally, we extend the well-known energy method to capture these effects, and conclude that it provides a good approximation and is useful for initializing the fully-coupled solver.

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“…And Xu has also done some meaningful works in friction contact by experimental and numerical methods [22][23][24][25][26]. By using a one-way coupled method, Lassalle and Firrone [27] investigated the nonlinear aeroelastic phenomena of a bladed disk system with friction contacts. In addition to the finite element (FE) model, the lump parameter model of the bladed disk system with dry friction damper was also established by some scholars.…”

Section: Introductionmentioning

confidence: 99%

Nonlinear Vibration Analysis of a Rotating Disk-Beam System Subjected to Dry Friction

She

Tang

et al. 2020

Shock and Vibration

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In this work, a continuum model is proposed to simulate and interpret the coupling vibration characteristics of a rotating disk-beam system with the dovetail interfaces. The dovetail interface feature is represented by a macroslip dry friction model. The present study also derives a new mode function to simulate the vibration of a rotating beam with loosely assembled dovetail attachment. The new proposed mode function is validated by comparing the natural characteristics and vibration response with those obtained from a finite element (FE) model. At last, based on the nonlinear response results obtained by the Newmark-β method, the effects of different parameters on the nonlinear dynamics of the coupling system are discussed. The following interesting phenomena have been revealed: the flexible disk can impose different influences on the response characteristics of the rotating beam. The effects of dry friction on the beam’s energy dissipation are significant, especially at a low rotational speed. Further analysis yields that the excitation level and friction coefficient also exhibit a significant impact on the damping effect of dry friction. Consequently, it should be noted that the optimal values of the contact surface’s parameters allow achieving a better damping effect in the engineering practice.

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A parametric study of Limit Cycle Oscillation of a bladed disk caused by flutter and friction at the blade root joints

Cited by 16 publications

References 33 publications

Investigation of a Methodology for Describing Fan Blade Flutter Limitations Induced by Non-Linear Friction at Blade Roots

Investigation of a Methodology for Describing Fan Blade Flutter Limitations Induced by Non-Linear Friction at Blade Roots

Development of a Fully-Coupled Harmonic Balance Method and a Refined Energy Method for the Computation of Flutter-Induced Limit Cycle Oscillations of Bladed Disks with Nonlinear Friction Contacts

Nonlinear Vibration Analysis of a Rotating Disk-Beam System Subjected to Dry Friction

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