A research on the internal sound field characteristics was conducted in order to reduce the running noise of self-priming vortex pump. The CFX software and Acoustic Harmonic BEM of LMS Virtual Lab software were combined to study the internal pressure pulsation and the noise generated. Firstly, the pressure fluctuations of self-priming vortex at 0.4 Qd, 0.6 Qd and Qd were obtained from the unsteady simulations with RNG k-ε turbulence model in the CFX software. Secondly, pressure fluctuations data were extracted and input into the LMS Virtual Lab software. Finally, the SPL of the pump discharge and the internal sound pressure distributions at different flows were obtained by acoustic field calculations. From the analysis of the CFD results and acoustic field calculations, it is concluded that the rotor-tongue interaction is the main cause of the noise. Results from the sawtooth structures on the trailing edge of turbine blade for reducing pressure pulsation, the CFD and acoustic field calculations show that the maximum amplitude of pressure pulsation decreases, by 20.0 % and 26.6 % respectively at Qd and low-flow rate. The SPL at Qd, decreases by 1.01 dB and 1.03 dB respectively in the inlet and outlet pipes. The SPL at low-flow rate, decreases by 8.57 dB and 2.65 dB respectively in the inlet and outlet pipes.
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