Influence of blade trailing edge profile on unsteady pressure pulsations in a multistage centrifugal pump

Abstract

AbstractChanging the shape of the blade trailing edge profile of a centrifugal pump is one of the effective means to improve the internal unsteady flow and pressure pulsation of a centrifugal pump. In this paper, the effect of four shapes of the blade trailing edge profile on the internal nonconstant pressure pulsation and internal flow of a multistage centrifugal pump is investigated by numerical simulation. The four types of blade trailing edges include prototype impeller (original trailing edge), pressure surface cut (ellipse on pressure side [EPS]), suction surface cut (ellipse on suction side [ESS]), and two‐side cut (ellipse on both sides). The results show that reasonable cutting of the trailing edge of the blade can reduce the pressure pulsation of the centrifugal pump. By comparing the pressure pulsation at fBPF, we found that the blade trailing edge profile can change the pressure pulsation. When the speed decreases, the periodicity of pressure pulsation becomes worse and the amplitude of pressure pulsation at fBPF decreases. The static pressure distribution at the trailing edge of the blade shows that EPS and ESS can effectively reduce the area of the high‐pressure gradient region at the trailing edge of the blade, and the dynamic–static interference effect is weakened, which leads to a lower pressure pulsation amplitude. The distribution of turbulent energy in different blade trailing edge centrifugal pumps corresponds to the distribution of static pressure in different blade trailing edge centrifugal pumps, further demonstrating the reliability of the static pressure distribution. The results of this study will further provide theoretical support for the optimization of the blade trailing edge profile.