CAJ | 학술논문

空化流动诱导的非定常激励是引起泵振动噪声的主要因素之一，为研究其特性，运用完整空化模型和混合流体两相流模型，对比转数为86的离心泵流道内部的空化流动进行非定常数值计算。结果表明，空化的初生位于叶片背面进口边附近，随着进口压力的下降，空泡不断向叶轮出口方向扩散，当空化现象严重时，流道内会出现低速漩涡区；流场中压力脉动频率存在明显离散特性，叶片通过频率下的脉动幅值较大；流场内压力脉动强度大小会随着空化发展程度的强弱相应发生改变，空化越严重，压力脉动越强烈，且叶轮所受径向力合力大小及监测时间内始末两时刻瞬时径向力差异也越大，同时非定常径向力波动幅度也较大；空化的发展还会导致轴向力的大幅增加，对泵运行的稳定性及泵轴的安全性造成影响。
공화류동유도적비정상격려시인기빙진동조성적주요인소지일，위연구기특성，운용완정공화모형화혼합류체량상류모형，대비전수위86적리심빙류도내부적공화류동진행비정상수치계산。결과표명，공화적초생위우협편배면진구변부근，수착진구압력적하강，공포불단향협륜출구방향확산，당공화현상엄중시，류도내회출현저속선와구；류장중압력맥동빈솔존재명현리산특성，협편통과빈솔하적맥동폭치교대；류장내압력맥동강도대소회수착공화발전정도적강약상응발생개변，공화월엄중，압력맥동월강렬，차협륜소수경향력합력대소급감측시간내시말량시각순시경향력차이야월대，동시비정상경향력파동폭도야교대；공화적발전환회도치축향력적대폭증가，대빙운행적은정성급빙축적안전성조성영향。
Unsteady excitation induced by cavitating flow is one of the main factors causing the vibration and noise of the pump. In order to study the characteristics of unsteady excitation, the unsteady numerical simulation of the cavitating flow in the flow-passage of a centrifugal pumps is carried out by using the full cavitation model and the mixed two-phase flow model. Simulation results indicates that the cavitation bubbles generate at the suction side of blades near the leading edge, the region of bubbles extends with the reduction of inlet total pressure. When cavitation becomes serious, low-speed vortex is observed in the flow-passage. The frequency of the pressure fluctuations has the obvious discrete characteristics and the blade passing frequency dominates the pressure fluctuations. Along with the development of cavitation, cavitating flow can induce the increase of pressure fluctuation amplitude in the flow-passage, and there is a corresponding relationship between them. The cavitation can also induce the increase of unsteady radial force fluctuation amplitude and substantial increase of axial force. So cavitation affects operation stability and reliability of pumps.