Analysis on Performances and Flow Fields of a Single Waterjet Propeller Based on SST k −ω Model

Abstract

As a special method of ship propulsion, waterjet propeller has been widely used in military and civilian fields due to its advantages of simple structures and high propulsion efficiency. Affected by waves of sea and rotation of impeller, the internal flow of waterjet propeller is extremely complex on three dimensions. When waterjet propeller works, its turbulent flow is often accompanied with unstable phenomena like flow separation, secondary flow, and backflow. On the other hand, the impeller of the propeller will be easily cavitated if it runs at high speed. That has a serious impact on performance and structure of the propeller. Therefore, understanding the open water performance and cavitation characteristics is imperative. In this study, we analyze the performance and flow field of a single marine external waterjet propeller based on the SST k−ω model. We focus on examining its performance under various advance coefficients in open water conditions. The experimental results show that the distributions of streamline and inlet velocity are more uniform at the highest efficiency point than other operating conditions. The loss for the generation of entropy is relatively low at the same time. The analysis on cavitation shows that the volume of the cavitation bubble will increase gradually as the cavitation number of the propeller decreases. Meanwhile, the performance of the propeller decreases obviously at the blade tip extending from the rim to the hub.