On the cavitation-induced collapse erosion of a turbofan fuel pump

Abstract

Cavitation is a challenging flow phenomenon that can adversely affect the hydraulic performance of centrifugal pumps. In this study, numerical investigations were carried out incorporating the Zwart cavitation model derived from Rayleigh–Plesset equation with the Navier–Stokes equations to study a damaged turbofan pump. Pressure fluctuation was analyzed with fast Fourier transform (FFT) in both non-cavitation and cavitation flow fields. The entropy production theory was used to further analyze the positions of vortex cores and energy-loss behaviors inside the pump. The results demonstrate that the numerically predicted positions of vortex cores in high-pressure regions agree well with the erosion positions determined under real working conditions. Herein, through combined analysis of the pressure contours and the vortex-core locations, we demonstrate that the erosion failure of the surface is caused by fatigue failure due to the collapse of cavities at vortex cores. The percentages of different kinds of entropy production rates under different mass flow rates in the whole calculation domain were calculated, and it was found that the impeller suffered the most energy loss. The results of the entropy production analysis can provide guidance for subsequent optimization of turbofan pumps.