基于Lighthill声类比理论,采用计算流体力学(CFD)和计算声学(CA)相结合的方法对离心泵内部声场进行了求解。首先采用SST SAS湍流模型对离心泵内部流场进行了三维非定常计算,并导出声源信息,然后在流场计算的基础上进行声学求解,比较研究声学边界元法和声学有限元法在应用时的优劣。结果表明:蜗壳隔舌附近压力脉动强度最大、声压级最高,叶片通过频率及其倍频是各监测点上压力脉动的主频,叶轮与隔舌间的动静干涉作用是离心泵流动诱导噪声的主要原因;随着流量的增加,总声压级逐步减小,在效率最高工况点上达到最小,随后上升,偏离效率最高工况点越多,宽频分量越明显;声学有限元法对离散噪声的预估比较有优势,能综合考虑湍流噪声的各种声源,对内流场宽频噪声问题的研究更占优势。
Based on Lighthill acoustic analogy theory,the interior acoustic field of a centrifugal pump was solved by using the method of CFD combined with the computational acoustics (CA).Firstly,the 3D unsteady computation was performed for the inner flow field in the centrifugal pump with the SST SAS turbulence model to deduce the acoustic source information,solve the acoustic field problem based on the results of the flow field computation,and compare advantages and disadvantages of BEM and FEM applied in this acoustic field problem.The results showed that the pressure fluctuation intensity near the volute tongues is the maximum and the sound pressure level is the highest; the blade passing frequency and its double-frequency is the main frequency of pressure fluctuation at each monitored point,the dynamic-static interaction between the impeller and volute tongues is the main cause of the centrifugal pump’s flow-induced noise; with increase in flow rate,the total sound pressure level gradually decreases to reach its minimum value at the operation case point with the highest efficiency and then increases; the more the deviation from the operation case point with the highest efficiency,the more obvious the wide-frequency band components; the acoustic FEM has obvious advantages in predicting discretized noise,this method can comprehensively consider various acoustic sources of turbulent noise,and it is more advantageous to studying the inner flow field wide-frequency band noise problems.