Prediction of Cavitation Evolution and Cavitation Erosion on Centrifugal Pump Blades by the DCM-RNG Method.

Han Zhu,Fanjie Deng,Xiang Liu,Chuan Wang,Ning Qiu,Jie Wu,Qiaorui Si,Qiao Yanxin

doi:10.1155/2021/6498451

Abstract

Cavitation can reduce the efficiency and service life of the centrifugal pumps, and a long-term operation under cavitation conditions will cause cavitation damage on the surface of material. The external characteristic test of the IS65-50-174 single-stage centrifugal pump was carried out. Moreover, the cavitation mechanism under specific conditions was analyzed by numerical simulation. Considering the macroscopic cavitation flow structure in the centrifugal pump, three different cavitation erosion prediction methods were used to predict the erodible areas. The results show that the calculation results obtained by the density correction method (DCM) can well match the flow characteristics of the centrifugal pump under the rated conditions. When the centrifugal pump head drops by 3%, cavitation mainly occurs on the suction surface, and the cavity on the pressure surface is mainly concentrated near the front cover. The cavitation prediction method based on the time derivation of pressure change is not suitable for centrifugal pumps, while the prediction result of the erosive power method is more reasonable than the others. At time 0.493114 s, the maximum erosive power appears on the blade near the volute tongue, and its value is 1.46e − 04 W.

Highlights

Cavitation is a common phenomenon in centrifugal pumps
The unsteady cavitation in the centrifugal pump is studied and analyzed by the method of combining experiment and numerical simulation, and the results show that
(2) the existence of cavitation in the centrifugal pump causes the blockage of the flow channel and the generation of vortexes, which leads to the decline of the performance of the centrifugal pump

Summary

Introduction

Cavitation is a common phenomenon in centrifugal pumps. When the centrifugal pump is running, the liquid pressure in local areas will be lower than the saturated vapor pressure at the operation temperature, resulting in cavitation [1]. Wang et al [14] studied the cavitation at the inlet of the centrifugal pump impeller and initially obtained the relationship between the cavitation distribution in the impeller and the vibration and noise characteristics of the pump. Wang et al [19] established the RZGB cavitation model considering the rotation effect, the structural characteristics of large curvature, and the compressibility of the liquid when studying the cavitation flow field in the centrifugal pump. Wang [21] proposed a cavitation prediction method based on Matlab image processing of cavitation clouds in the centrifugal pump. Their results show that the cavitation location in the centrifugal pump is basically the same as the cavitation erosion area. The density-corrected RNG k − ε model was used for cavitation simulation, and three different cavitation erosion prediction methods were used to predict cavitation erosion on the blade surface of the centrifugal pump

Centrifugal Pump Parameters and Experimental Setup

Numerical Simulation Methods

Results and Discussion

Conclusion