Fully transient CFD analyses of waterjet pumps

This paper presents results of fully transient calculations of flow through waterjet pumps. The fully transient method is based on a moving mesh option to implement the rotation of the impeller. In this way, the time-dependent forces acting on the impeller can be determined. These forces can be divided into axial and radial forces, for example, as a result of rotor-stator interaction. In waterjet applications, the nonuniform inflow velocity distribution creates an additional radial impeller force that is steady in the inertial frame of reference. Computational fluid dynamics (CFD) analyses are made of two Lips-Jets waterjet pumps equipped with three- and six-bladed impellers to investigate the rotor-stator interaction force for various flow rates. Calculations with nonuniform inflow velocity distributions are made to determine the steady radial forces. The strength of this steady force depends on the level of inflow nonuniformity and the flow rate through the pump.