Numerical computation for the impact of flow rate and rotational speed on the flow-induced noise of the centrifugal pump

Abstract

This paper adopted an indirect mixed method (computational fluid dynamics + boundary element method) based on computational fluid dynamics + Lighthill acoustic analogy theories to compute the flow field and flow-induced noise of the centrifugal pump, and experimentally verified the correctness of computational results. The pressure distribution of the centrifugal pump through an unsteady computation showed that there were obvious separation vortexes at the outlet of the centrifugal pump and pressure at the edge of impellers was obviously more than that of other parts. There were many peak noises on the sound pressure level curve at the outlet of the centrifugal pump. The sound pressure level gradually decreased with the increased frequency. However, sound pressure levels will be a stable value when the analyzed frequency was more than 3000 Hz. Sound pressures at the inlet and outlet of the centrifugal pump were relatively large. Sound pressures at the inlet pipeline gradually decreased from outside to inside and sound pressures of outlet pipeline gradually decreased from inside to outside. The structure of the centrifugal pump was not completely symmetrical, and the sound field was not symmetrical. In addition, the radiation noises in the external field at the inlet and outlet of the centrifugal pump were similar to the radiation of many point sound sources. Peak values of flow-induced noises at the outlet of the centrifugal pump were more than those at the inlet of the centrifugal pump under the working condition of different rotational speeds and flow rates. In the meanwhile, sound pressure levels at the inlet and outlet of the centrifugal pump did not show many differences in amplitudes when the rotational speed was small. When the rotational speed reached up to 3000 r/min, the sound pressure at inlet was more than that at outlet within 1500 Hz-4500 Hz. At many peak frequency points, peak noises at outlet were obviously more than those at inlet, which thus proved that fluid caused large pressure fluctuations due to the interaction between impellers and volutes after flowing through the centrifugal pump and flow-induced noises caused by pressure fluctuations were mainly reflected in blade frequency. The change of the rotational speed and flow rate would not only increase the flow-induced noise in the centrifugal pump, but also seriously affect the external radiation sound field of the centrifugal pump.

Impact of Transient Gas Injection on Flow-Induced Noise in Centrifugal Pumps

“…Subsequently, research on the noise induced by gasliquid two-phase flow in the pump was conducted, and the noise mechanism caused by the gas-liquid two-phase flow in the pump was preliminarily elaborated. Wang et al (2017), Si et al (2020), Liu et al (2016), Gao et al (2017), and Dong et al (2018) studied the noise in centrifugal pumps under different operating conditions by performing experiments and numerical simulations. They analysed the effects of rotational speed, flow rate, cavitation (Rehman et al 2013;Jaiswal et al 2019Jaiswal et al , 2022, and backflow (Si et al 2013) on flow-induced noise in pumps.…”

Influence of rotational speed on performance of low specific speed hydraulic turbine in turbine mode

“…However, in the experimental test and production operation of pump, variable speed operation is generally used to solve this problem and the technology is mature. 17–23 Therefore, based on the experience of pump, some scholars have studied the effect of rotational speed on performance of turbine. 24 Buono et al 25 and Yang et al 26 theoretically deduced the performance of reverse pump turbine at different rotational speeds, and verified the feasibility of the theory by experiment and numerical calculation.…”

Study on acoustic source characteristics of gas pipeline leakage

“…Based on the analysis of the flow field, the characteristics of the acoustic source emitted by gas pipeline leakage with the leakage hole diameter of 5 mm and below are simulated by the Lighthill acoustic analogy method. 10 Then, the simulation results are compared with experimental results and the feasibility and accuracy of the method are proved. Finally, the simulation and experimental methods are summarized to study the characteristics of acoustic source emitted by gas pipeline leakage, which provide theoretical basis for the engineering application of leak detection for gas pipeline based on acoustic method.…”