A Modal Coupling for Fluid and Structure Analyses of Turbomachine Flutter: Application to a Fan Stage

Abstract

The paper presents an approach for the modal aeroelastic analysis of three-dimensional turbomachinery bladings with several fluid and structure analyzers. Structure analyzers are three-dimensional solvers for static and dynamic analyses of axisymmetric/cyclic-symmetric blade-shroud-disk-shaft assemblies with/without elastic coupling between blades. Fluid analyzers are two-dimensional/three-dimensional solvers for single/multi-stage steady/unsteady turbomachinery flows. An automatic interfacing procedure for exchanging data at the incompatible fluid-structure boundary and the development of a multi-model interfacing software are discussed. The modal aeroelastic analysis of a first stage shrouded fan is carried out to illustrate the main issues of the paper. In particular, two structural models for the elastic coupling of the part-span shrouds are discussed. The results show the strong dependence of the structure dynamics and aeroelastic analysis on this modelling.

Aeroelasticity in Turbomachines: Some Aspects of the Effect of Coupling Modeling and Blade Material Changes

“…Third, since different discretizations and different meshes are usually used for structure and fluid, compatibility problems at the interface should be solved before any computation. As shown for example by JacquetRichardet et al (1994) and by Moyroud et al (1996), these drawbacks can be efficiently overcome using a linearized modal approach. ( 12) In this case, the aeroelastic eigenvalue/eigenvector problem reduces to (15) is homogeneous to the work per…”

“…(1984), Srinivasan and Fabunmi (1984), Smith (1991), Gerolymos (1993), Jacquet-Richardet and Henry (1994), Imregun (1995), Moyroud et al (1996). This paper first describes a modal aeroelastic analysis method adapted to turbomachinery flutter analyses.…”

Comportement dynamique des ensembles tournants de turbomachines couplés aux fluides environnants

“…Sur chaque élément la pression est connue en chaque noeud. Les forces modales sont obtenues, simplement, après calcul des forces nodales équivalentes, assemblage et interpolation des déplacements sur le maillage d'interface [9] .…”

A Coupled Fluid–structure Analysis for 3-D Inviscid Flutter of Iv Standard Configuration

“…Since the early 1980s a number of time accurate Euler and Navier}Stokes procedures have been developed to predict blade row unsteady #ows in which unsteadiness is caused by aerodynamic disturbances at the in#ow or out#ow boundaries, relative motions between the blade rows, or blade vibrations. The traditional approach in #utter calculations of bladed disks is based on frequency domain analysis [1,2], in which the blade motions are assumed to be harmonic functions of time with a constant phase lag between adjacent blades, and the mode shapes and frequencies are obtained from structural computations. This approach ignores the feedback e!ect of the #uid on the structural vibration.…”