Vibration analysis and control of a screw compressor outlet piping system

Abstract

The severe vibration of a screw compressor outlet piping system caused the premature failures of some thermowells and the unplanned shut down of the compressor system. The root causes of the vibration problem were investigated by numerical simulations. An acoustic model was established to predict the pressure pulsation of the gas inside the pipelines, and two finite element models were built to study the vibration characteristics of the overall piping system and of the thermowells. The numerical results indicated that the vibration problem may be attributed to the excessive pressure nonuniformity of the gas inside the pipelines, low overall stiffness of the piping system and the first-order structural resonance occurred on the thermowells. A pulsation attenuator was added and the pipelines were rearranged to reduce the pressure pulsation, some pipe supports were added to improve the overall stiffness of the piping system, and the thermowells were reinforced to avoid the first-order structural resonance. After the modifications, the field measurement data showed that the vibration of the piping system decreased significantly, and the modified piping system has been operating normally for nearly two years.

A Review of Recent Research and Application Progress in Screw Machines

“…The gas pulsation and mechanical vibration occurred in the twin screw machines would be transported outwards and cause severe vibration in the outlet piping system. Zhao et al [96] proposed some practical measures to successfully reduce the vibration of the piping system, i.e., adding a pulsation attenuator, rearranging the pipelines, adding some pipe supports, and reinforcing the thermowells.…”

Vibration Diagnosis and Treatment for a Scrubber System Connected to a Reciprocating Compressor

“…The transfer matrices of the inlet pipeline, scrubber itself, and outlet pipeline are given by Equations ( 3), (4), and (5), respectively. So the matrix equation of an acoustic model for the scrubber system can be expressed by Equations (6).…”

“…Researches concerning such vibration have been focusing on three different areas: vibration theory and analysis, vibration diagnosis and identification techniques, and vibration control methods. Vibration theory and analysis mainly include establishment of a vibration model, analytical and numerical solutions of the vibration model [1,2], modal analysis for avoidance of resonance, vibration analysis and related experimental research [3], fluid-structure interaction (FSI) vibration study [4,5], vibration dynamic response of system, acoustic and pulsation analysis using acoustic wave theory, transfer matrix method, and finite element methods [6,7]. Numerous vibration analysis techniques are employed to predict the vibration level of system during the design phase and to identify the source of high vibration in the operation phase, which mainly focus on field measurement methods, test instrumentation, signal processing, and frequency spectrum analysis [8,9].…”

A methodology for flexibility analysis of pipeline systems

“…On the other hand, adoption of beam element model is considered reasonable if the pipeline length is considerably larger than the diameter value. 51 Several engineering practices validate the adoption of beam model if pipeline diameter-thickness ratio is less than 100. 52,53 For this reason, CAESAR II was duly utilized for beam modeling since pipeline diameter-thickness ratio is around 38 for the proposed model configuration.…”