空化流对管路振动的影响与分析

Influence and analysis of cavitation flow on pipeline vibration

管路系统空化流动诱导的管路振动是导致管路破坏的重要因素.重点研究流动扰动与空化的相互作用,以及对管路振动的影响.采用Zwart-Gerber-Belamri(ZGB)空化模型研究小扰动下空化云随空化数及雷诺数的动态演变规律,发现空化云会引起管路的不平衡力和流量脉动.同时,空化云会加剧不平衡力和流量脉动的脉动幅值以及改变频率的调幅变频特性.在此基础上,将空化激励等效为激励源项引入传统管路流固耦合动力模型,得到一种改进的分析管路振动空化诱导机制的流固耦合动力学模型,对空化激励下的管路进行振动求解,给出临界空化数区间,同时揭示小扰动下空化诱导管路振动的原因.所得结果对研究空化管路系统的减振降噪及安全运行具有重要意义.

Pipe vibration induced by cavitatingflow in a pipe system is an important factor that damages the pipe system.This paper focuses on the interaction betweenflow disturbance and cavitation,as well as its impact on pipeline vibration.Zwart-GerberBelamri(ZGB)cavitation model is used to study the dynamic evolution of the cavitation cloud with the cavitation number and Reynolds number under the influence of small perturbations.The cavitation cloud is found to cause an unbalanced force andflow pulsation in the pipeline.Furthermore,the cavitation cloud has amplitude modulation and frequency conversion characteristics,which aggravate the amplitude and change the frequency of the unbalanced force andflow pulsation.Based on this,an excitation source term,cavitation excitation,is introduced into thefluid structure coupling dynamic model,and an improvedfluid structure coupling dynamic model for analyzing the mechanism of pipeline vibration induced by cavitation is established.The equations for the vibration of a pipeline under cavitation excitation are solved,and the critical cavitation number interval is determined.Moreover,the causes of pipeline vibrations induced by cavitation under small perturbations are revealed.The results are essential for studying vibration and noise reduction and the safe operation of pipeline systems.