Hydrodynamic Design and Pulsation Evolution in an Axial-Flow Pump Based on Control Mechanism of Flow-Induced Excitation

Abstract

The physical mechanism, evolution process, and control method on pulsation caused by flow-induced excitation vortex in an axial flow pump are elaborated by numerical calculation and experiment. The mechanism formulation of flow-induced excitation vibration and the unique hydrodynamic design method of airfoil are proposed with three contrast models. According to the action law of inertial centrifugal force in the rotor–stator interaction (RSI) region and guide vane airfoil, the evaluation method between vortex transport, turbulent kinetic energy (TKE) and flow structure under transient and steady-state of internal flow field is established, which navigates the instability of energy intensity determined by the uneven gradient distribution. The distribution characteristics of flow-induced excitation pulsation in the RSI region and the static region are quantitatively verified by experiment. Along the streamwise direction, the excitation loss changes from impact loss to flow loss, with the RSI vortex affected by wake-jet flow vortices transforming into intervane vortex in the guide vane. In pulsation evaluation, the excitation pulsation form changes from blade frequency fBPF to low frequency band. Overall, the generation analysis of the excitation pulsation is realized based on the hydrodynamic optimal design with the comparison of models, which provides guidance for the optimization design of the axial flow pump to reduce vibration and energy consumption of the cooling system.