Study on the influence of blade outlet cutting on hydraulic noise of centrifugal pump with low specific speed

Abstract

In order to study the influence of blade outlet cutting width on hydrodynamic excitation noise of the centrifugal pump with low specific speed, five schemes are used to perform V-shaped cutting on the outlet of the impeller blade are studied in this study. Based on Lighthill acoustic analogy, combining computational fluid dynamics and computational acoustics, RNG k-ε turbulence model is used to calculate internal unsteady flow field of the centrifugal pump, and the acoustic solution is based on the flow field calculation. The results show that the pressure pulsation can reflect the sound pressure level to a certain extent; proper cutting of the blade outlet can improve the flow state of the rear cavity of the centrifugal pump and make the flow uniform; the V-shaped cutting of the blade outlet also can reduce the dynamic and static interference between the impeller outlet and the volute tongue, effectively reducing the sound pressure level of the internal sound field, when the blade outlet cutting width is a/ b2 = 33.33%, the inlet sound pressure level and the outlet sound pressure level are decreased by 4.8% and 7.2%, respectively. In terms of internal sound field, the sound pressure level at the outlet of the pump is obviously higher than that at the inlet.

Numerical Study of the Effect of Splitter Blades on the Flow-Induced Noise of Hydraulic Turbine

“…The noise source of the FW-H equation in the dipole source term is related to the pressure pulsation. Some scholars believe that the strongest point of pressure pulsation inside the hydraulic turbine occurs at the volute tongue, so it is particularly important to analyze the induced noise of the hydraulic turbine of the pressure pulsation at the volute tongue [22]. In the unsteady calculation of the flow field, the monitoring point P1 is located at the tongue of the volute spacer, as shown in Fig.…”

“…As a typical rotating machinery, research on the vibration and noise of centrifugal pumps has been fruitful at home and abroad [5][6][7][8][9]. Cheng et al [10] improved the noise of a centrifugal pump by cutting the outlet side of the impeller, and found that there exists an optimal cutting width to weaken the rotorstator interaction between the impeller and the volute, which effectively reduces its internal and external sound field. To study the mechanism of noise induced by unstable flow inside a centrifugal pump, Lu et al [11] analyzed it through a combination of experiments and numerical simulations and found that the noise could effectively react to the phenomena of flow stall and instability inside the pumps.…”

Investigation on the Changing Characteristics of Flow-Induced Noise in a Centrifugal Pump

“…It was showed that the noise decreased first, then increased with the increase of blade number. Cheng et al [20] investigated the impact of blade outlet cutting on the noise at pump inlet and outlet. The results showed that the V-shaped cutting improved the noise performance.…”