The hydrodynamic characteristics analysis of a centrifugal pump with the impeller angular misalignment fault

As a typical fluid machine, the centrifugal pump system experiences impeller angular misalignment resulting from manufacturing and assembly errors. A new computational fluid dynamics (CFD) simulation model is developed to investigate the effect of impeller angle misalignment on the internal flow characteristics of a centrifugal pump. The transient flow is described by applying the shear stress transport (SST) k-ω turbulence model. The results reveal that an increase in the impeller angular misalignment exacerbates the flow inhomogeneity and instability. This failure can reduce the head and efficiency; it can increase the flow turbulence in the pump. Furthermore, the angular misalignment leads to an elevated circumferential pressure gradient at the inlet and outlet of the impeller. It amplifies the peaks of axial frequencies and their harmonics, which can disrupt the uniformity of the radial force distribution. This study provides some valuable numerical references for the analysis of angular misalignment failures and vibration control. It can also offer a basis for the optimal design and vibration mitigation of centrifugal pump impellers.