ASPECTS OF PERFORMANCE EVALUATION OF WATERJET PROPULSION SYSTEMS AND A CRITICAL REVIEW OF THE STATE-OF-THE-ART
DAVID W TAYLOR NAVAL SHIP RESEARCH AND DEVELOPMENT CENTER BETHESDA MD DEPT OF HYDROMECHANICS
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Characteristics peculiar to waterjets may make this type propulsion capable of overcoming some of the problems facing high-speed marine propulsion. As a basis for judging the potential of waterjets in relation to other propulsion methods, a study was conducted to determine the state-of-the-art of waterjet technology. Available literature was surveyed with particular emphases on 1 performance criteria and performance data, and 2 performance evaluation and experimental techniques. Although the greatest apparent need is for experimental information on the design of efficient and cavitation-free high-speed inlets, work is also needed on light-weight pumps which are capable of sustained high performance under relatively severe cavitation conditions. It was found in the literature that thrust efficiency was usually confused with propulsive efficiency. Propulsion efficiency is equivalent to the product of thrust efficiency and the hullwaterjet interaction efficiency. Therefore, propulsive efficiency is a more definitive performance parameter but is inherently more difficult to obtain. The requirement of separating resistance and propulsive forces in determining this efficiency leads to model experiments. A review of model experimental techniques and facilities shows the capability for carrying out the necessary experiments.
- Marine Engineering