Performance Analysis of a Four Waterjet Propulsion System for a Large Sealift Ship

摘要

The prediction of waterjet propulsion performance using tow tank model testing has been a recent, ongoing area of research. The ITTC Waterjet Performance Prediction Specialist Committee was active in the 21~(st) (Hoyt 1999), 22~(nd) (Van Terwisga 2002), and 23~(rd) (Van Terwisga 2005) ITTC committee period tasked with developing a model testing procedure for waterjet propulsion. It has been generally accepted that conventional shaft dynamometer propulsion tests are not suitable due to scale effects on pump performance, and often the use of surrogate model pumps. The committee adopted a control volume approach balancing momentum and energy through the waterjet system to arrive at system thrust, thrust deduction, and delivered power. From assumptions made for the full scale pump efficiency, and inflow wake scaling, a prediction of full scale delivered power can be made. The committee identified areas of largest uncertainty as the accurate measure of the pump mass flow due to flow nonuniformity in the exhaust nozzles, the measure of hull resistance, and the establishment of the proper tow force.