Analytical Study of Piping Flow-induced Vibration. Example of Implementation

摘要

The paper presents methodology for analysis of piping vibration state. The acoustic resonance of medium (steam orwater) is considered as most probable source of flow-induced vibration.For analysis of piping vibration induced by steady-state processes in a transmitted medium the mathematical modeland corresponding computer code NETPULS are developed for evaluation of an acoustic oscillation in a liquid orgaseous medium. Acoustic excitation can arise in the pipeline discontinuities such as tees, branches etc. And also can becaused by external sources connected to the pipeline. NETPULS is based on linearized mathematical model of quasistationaryacoustic oscillation in the compressed medium. Mathematical model of this process takes into accountinfluence of non-linear damping due to hydraulic friction and local hydraulic losses.The amplitude-frequency and phase-frequency characteristics of the gas-dynamic forces acting upon the pipingdiscontinuities (bends, tees, branches etc.) are defined. The output obtained by NETPULS can be used as input data forconsequent calculation of mechanical vibrations of pipelines and evaluation of effectiveness of damping devices.Implementation of the described approach is illustrated on a basis of practical measurements and numerical analysisof typical NPP steam line.