导叶开度对混流式水轮机压力脉动特性及流动诱导噪声的影响

为研究导叶开度对混流式水轮机压力脉动特性及流动诱导噪声的影响,应用CFD和LMS Virtual Lab软件分别对混流式水轮机在三种导叶开度下进行非定常流场和声场数值计算。结果表明:混流式水轮机内压力脉动主要受到叶片通过频率(108.33Hz)以及低频脉动(4.15Hz)的影响;随着导叶开度的增大,叶频对转轮进口和蜗壳内压力脉动的影响逐渐增加;外场噪声的分布与混流式水轮机的几何轮廓相吻合;尾水管弯肘段有助于减弱混流式水轮机流动噪声声压;导叶开度越大,混流式水轮机辐射出的外场噪声声压值越大,偶极子特性越明显。研究结果可为混流式水轮机组的稳定运行及流动诱导噪声的控制提供参考。

The influence of guide vane opening on pressure pulsation characteristics and flow-induced noise in Francis turbine

In or der t o study the influence of different g uide v ane o penings on the pressur e pulsat ion characteristics and flow2in2 duced no ise in Fr ancis tur bine, we used CFD and LM S Virtual Lab softw are to calculate t he unsteady flow field and sound field in a Francis turbine under three g uide v ane o pening degr ees. The results showed that the pressure pulsat ion in the Francis tur2 bine was mainly affected by the r otation fr equency of blade ( 1081 33 H z) and the low2fr equency pressur e2pulse ( 41 15 Hz) . With the increase of t he g uide v ane opening, the influence of blade frequency on the pr essure pulsatio n in t he inlet of the r unner and the v olute w ould g radually increase. The distributio n of o utfield noise accor ded w ith the g eometric contour of the Fr ancis tur2 bine. T he elbow section o f the draft t ube w as helpful for the attenuation o f the flow2induced no ise of the Francis turbine. T he gr eat er the guide vane opening , the g reater the sound pr essure of the exter na l no ise g enerat ed by the Francis tur bine, and the more o bv ious the dipo le cha racteristics. The research results can pr ovide a r efer ence fo r the stable o per atio n o f Francis turbine and the co nt rol of flow2induced noise.