Multiphase numerical analysis of the vortex formation near the suction of the vertically mounted axial-flow pump with influence of the free water level

Abstract

Presented paper deals with the numerical investigation of a flow in a complete hydraulic system of a pump station. The station uses a recently developed high-efficiency axial-flow pump with the specific speed ns=680 min-1. The pump is vertically mounted in the suction object with the free water level and equipped with the suction bell and the suction cone with one rib. For the numerical simulations, the lowest possible water level is considered. Such scenario is the most limiting for the pump station design and need to be analysed properly. The unsteady multiphase numerical simulations were focused on the creation of the complex vortical structures at the suction part of the mentioned axial-flow pump. This phenomenon strongly influences the pump performance (hydraulic efficiency, delivery and suction head, etc.) and operation (especially the vibrations and noise) characteristics. The unsteady flows inside the investigated domains are simulated using Ansys Fluent with appropriate solver settings. The Scale Resolving Simulations (SRS) are used to model large vortices and the interaction between stationary and rotating parts.