Interaction between non-uniform inflow and rotor–stator interference in a centrifugal pump

An unsteady numerical calculation method was performed to investigate the hydraulic excitation suppression mechanism in volute centrifugal pumps with non-uniform inflow. The propagation characteristics of hydraulic excitation interaction, influence of non-uniform inflow, and rotor–stator interference were systematically analyzed. Results reveal that non-uniform inflow primarily originates from three dominant vertical structures: secondary flow vortices in the elbow inlet, baffle-separated vortices, and high-curvature side-separated vortices. By the way, non-uniform inflow exhibits three periodic pressure peaks within a single rotation cycle: the first from the reverse vortex disturbance of the secondary flow vortices in the elbow inlet pipe, the second from the rotor–stator interaction between the blade trailing edge and the volute tongue; and the third from the flow separation induced by the high-curvature side-separated vortices in the elbow inlet pipe. By adjusting the elbow inlet deflection angle to modulate phase differences between adjacent pressure peaks, mutual energy cancelation was achieved, notably filling the first pressure valley with the second peak. This phase modulation reduced the maximum amplitude of the second peak by up to 33%, effectively suppressing hydraulic excitation and enhancing flow stability. It provides valuable theoretical support for the design and application of centrifugal pumps with non-uniform inflow.