AN INTEGRATED NONLINEAR APPROACH FOR TURBOMACHINERY FORCED RESPONSE PREDICTION. PART I: FORMULATION

• Published in: Journal of fluids and structures Vol. 14; no. 1; pp. 87 - 101
• Main Authors: SAYMA, A.I., VAHDATI, M., IMREGUN, M.
• Format: Journal Article
• Language: English
• Published: London Elsevier Ltd 01-01-2000; Elsevier
• Subjects: Aerodynamics; Applied fluid mechanics; Exact sciences and technology; Fluid dynamics; Fundamental areas of phenomenology (including applications); Physics; Turbulence; Blades; Forced vibration; Digital simulation; Prediction; Aerodynamics; Boundary conditions; Data structures; Turbomachinery; Unsteady flow; Structural models; Vibration damping; Friction; Specifications; Non linear effect; Iterative methods; Navier-Stokes equations
• ISSN: 0889-9746; 1095-8622
• DOI: 10.1006/jfls.1999.0253

This paper describes the formulation of an advanced numerical model for the simulation of high- and low-engine-order forced response for turbomachinery applications. The various forced response mechanisms are explained in some detail and a specification for an accurate prediction system is discussed with emphasis on both fluid and structural modelling aspects. The Favre-averaged Navier–Stokes equations are used to represent the unsteady flow in a nonlinear time-accurate fashion. Features such as turbulence modelling, boundary conditions, meshing strategies and numerical treatments are discussed in detail. The structural model is based on a linear modal model, though local nonlinearities due friction dampers can be accommodated using an iterative scheme. The fluid mesh is moved at each-time step according to the structural motion, so that changes in blade aerodynamic damping and flow unsteadiness can be accommodated. It is concluded that the model can be used for large simulations involving multi-bladerow whole-annulus calculations.