Capturing the Dynamics of Rotating Machines A Modern Global Approach Based on SAMCEF Rotor精品.pdfVIP

Capturing the Dynamics of Rotating Machines: A Modern Global Approach Based on SAMCEF Rotor P. Morelle Abstract The paper presents first a description of the methods used for the analysis of global dynamics of rotating systems like jet engines, gas and steam turbines. The growing necessity to simulate not just the rotating parts, but the global assembly of rotors, stators and linking devices leads to new design methodologies allowing to capture more accurately global but also local phenomena as well as the impact of more and more demanding features like highly nonlinear bearings, the effect of gaps and clearances, etc. The fact a machine is not one single piece but an assembly of parts connected by semi-rigid joints has an influence on the global and local dynamics of the system. More importantly, novel methods are described with the goal to calculate very accurately both global (bending, torsion …) but also local (blade) modes related to multistage compressors. The use of inertial and rotating frame approaches is discussed when the goal is to describe rotors and stators in a full 3D way so to take into account not just 3D geometrical details but also, for example, centrifuge stiffening. Different applications related to jet engines, gas and steam turbines, turbochargers are described and discussed. 1 Introduction When dealing with dynamics of rotating machines, gyroscopic effect has the con- sequence that eigenmodes and frequencies are not constant any more but vary with the speed of rotation. At the mathematical point of view, the dynamics of the system (natural vibrations) is described by a complex eigenvalue problem: k2M þ kB ðXÞ þ K ðXÞq ¼ 0 ð1Þ P. Morelle () Samcef Rotor, Siemens PL, Samtech (Liege), Munich, Germany e-mail: Patrick.morelle@ © Springer International Publishing Switzerland 2015