Abstract:

：The numerical simulation and experimental investigation are performed on flow-induced interior noise in a centrifugal pump as turbine(PAT). Under typical flow conditions, the casing dipole source is obtained using Reynolds-average method. The flow-borne noise and flow-induced structure noise in interior acoustic field are solved by boundary element method(BEM) and finite element method/ boundary element method(FEM/BEM), respectively. On the basis of this, the spectrum characteristics of each noise source and their contribution to interior noise are distinguished. Meanwhile, the noise spectra are evaluated by hydrophone placed at the outlet of PAT. The results show that the spectrum of flow-induced noise is mainly concentrated on low and medium frequency bands, with enhanced low-frequency spectrum behavior under small flow conditions. The spectrum versus frequency curve of flow-borne noise considering structure agrees well with experimental results, especially in larger flow conditions. The flow-borne noise is the biggest contributor to interior noise, followed by flow-borne noise considering structure, and the flow-induced structure noise is least. The structure increases sound pressure at second order blade passing frequency, lowers sound pressure at the rest discrete and broadband frequencies. The results can provide some reference for low noise design of similar turbomachinery.

Key words: Zigong 643000), Sichuan University of Science & Engineering