Reduced Order Modeling of Mistuned Bladed Disks considering Aerodynamic Coupling and Mode Family Interaction

Authors

Sebastian Willeke - Institute of Dynamics and Vibration Research, Leibniz Universität Hannover
Christian Keller - Institute of Turbomachinery and Fluid Dynamics, Leibniz Universität Hannover
Lars Panning-von Scheidt - Institute of Dynamics and Vibration Research, Leibniz Universität Hannover
Joerg R. Seume - Institute of Turbomachinery and Fluid Dynamics, Leibniz Universität Hannover
Joerg Wallaschek - Institute of Dynamics and Vibration Research, Leibniz Universität Hannover

Abstract

A substructure-based reduced order model for the numerical prediction of the mistuned dynamics of bladed disks is presented. The structural mistuning is introduced to the tuned disk by blade-to-blade variations of the natural frequencies. Aeroelastic influence coeffi-cients provide aerodynamic inter-blade and inter-modal coupling via the fluid flow. The accuracy and efficiency of the reduced modeling approach are highlighted by a compar-ison with conventional FEA simulations and unsteady CFD results. In total, the model reduction provides a computational saving of up to 90% while predicting the amplitudes of forced vibrations within a tolerance of 0.7%. The proposed modeling technique is used to analyze the forced response and the aeroelastic stability of an axial compressor blisk. This exemplary study reveals an attenuation of the mistuned response due to an increase in aerodynamic damping. The intentionally provoked interaction of two mode families illustrates the significance of the inter-modal aerodynamic coupling.