A Review of Aerodynamically Induced Forces Acting on Centrifugal Compressors, and Resulting Vibration Characteristics of Rotors

Abstract

This tutorial reviews the various types of forces that can cause non-synchronous vibrations in centrifugal compressors. Many of these forces are aerodynamically-induced, such as impeller or diffuser stall or impeller / diffuser misalignment. The presentation includes a description of the phenomena, their most common root causes, the resulting impact on the rotor vibration characteristics, and ways to distinguish between the various phenomena. Attendees will see examples of real time wave forms (oscilloscope output) and frequency spectra (FFT output) captured from compressors that experienced the various phenomena. This tutorial should be of interest to compressor operators, field service personnel, rotating equipment specialists and/or anyone who works with turbomachinery.