Effects of non-uniform inflow on the spatial and temporal distribution of impeller excitation in axial flow pumps in water tunnels

The effect of non-uniform inflow on the spatial and temporal distribution of impeller excitation is investigated. The experiments are first conducted to verify the hydraulic performance of the axial flow pump and to provide a reference for the accuracy of the numerical simulations. Subsequently, the effect of non-uniform inflow on the spatial and temporal distribution of the flow field and impeller load is investigated. The results indicate that the non-uniform inflow modifies the velocity distribution at the impeller inlet, resulting in alterations in the attack angle and subsequently affecting the radial and circumferential distribution of the impeller load. The extreme difference in the head between the different blades can reach up to 36 % of the total head. Furthermore, velocity pulsation and attack pulsation exhibit more pronounced fluctuations in the low-speed region, and there exists a strong correlation between the amplitude of unsteady forces and the magnitude of the impeller load.