Bubble Augmented Waterjet Propulsion: Two-Phase Model Development and Experimental Validation

摘要

The concept of thrust augmentation through bubble injection into a waterjet has been the subject of many patents and publications over the past several decades. Computational and experimental evidences of the augmentation of the jet thrust through bubble growth in the jet stream explain recent rise in interest in the concept. To generalize the idea to practical designs, an adequately validated modeling tool is needed especially since published models are based on significant simplifications. In this paper, we present numerical and experimental studies which aim at developing and validating a numerical code to simulate and predict the performance of a two-phase flow water jet propulsion system. The numerical model is based on the two-way coupling between the flow field and the Lagrangian tracking of large number of bubbles using the Surface Averaged Pressure (SAP) model. Validation studies are conducted using experiments with a two-dimensional flow bubble-augmented propulsion test setup. Bubbles were introduced into the flow with various injection methods, and the bubble behaviors were observed. The velocity and pressure fields were measured, and thrust augmentation was deduced from these measurements. Results show measurable thrust augmentation.