Toward Predicting Performance of an Axial Flow Waterjet Including the Effects of Cavitation and Thrust Breakdown

Abstract

Waterjet propulsion has gained increasing attention from the U.S. Navy in recent years. Waterjets enjoy several advantages over traditional screw propellers including shallow draft, increased maneuverability, and high-speed capability. Also in recent years, significant progress has been made in the prediction of waterjet performance with Reynold’s Averaged Navier Stokes (RANS) based Computational Fluid Dynamics (CFD) tools. These predictions have included detailed analysis of torque and head rise values which are essential to the design and analysis of a waterjet system. The ultimate goal of the present work is to predict these values including the effects of cavitation and thrust breakdown using a Naval Surface Warfare Center Carderock Division (NSWCCD) internally developed version of a non-commercial RANS code. This paper outlines the preliminary progress that has been made towards this goal. The following sections outline the mesh generation and flow solver development, and give comparisons with the measured data at model scale. The waterjet of interest is the U.S. Navy Office of Naval Research’s Axial-flow Waterjet One pump. The model scale test comparison calculations are made at several steady-state flow conditions for a rotor only case. The RANS solver developed in the study is based on the Open Field Operation and Manipulation (OpenFOAM) CFD library. The computational mesh was generated using the commercially available Ansys IcemCFD Hexa utility.