Compressor Discharge Pipe Failure Investigation With A Review Of Surge, Rotating Stall, And Piping Resonance.

LecturePg. 49-60Rotating stall, even with multiple cells, can contribute to piping excitation due to acoustic energy traveling down the pipe as a plane wave. The main objective of the paper is to describe causes and solution of fatigue cracks in discharge piping due to two forms of acoustic energy, with occasional direct surge loading of a 50,000 hp centrifugal compressor. Described are transverse modes of the gas inside pipes, as well as structural mode interaction of pipe shell modes. Also reviewed are frequency and force evaluation for two other cases of one-cell, rotating stall due to impeller eye incidence that caused rotor vibration in high-pressure centrifugal compressors. Single-stage rig tests, correlated with analytical results including computational fluid dynamics (CFD), are essential to validate aerodynamic design calculations for new impeller stages. Some typical test results are shown to confirm why a design not only is accepted, but also can occasionally be rejected