Research of relationship between waterjet power absorption and ship speed

The relationship between the waterjet power absorption and ship speed is analyzed by a case study about anewly-designed waterjet propulsion system. Firstly, from the application of the dyna- mic equations of waterjet propulsion system the waterjet power absorption characteristic isintroduced in the research ofsteady-state and dynamic propertiesof the waterjet propulsion system. Then the torque property of the waterjet is analyzed after the rotary speed curvesof the waterjet, i.e. the rotary speed versus absorbed power boat speeds, are transformedto the torque curves, which iscompared with the screw propulsion systemas well. The effect of ship speed onthe waterjet power absorption characteristic is analyzed after three power absorption curves at different ship speedsare obtained according to the rotary-speed curvesof waterjet, and these power absorption curves are also compared with those of the screw propulsion system. The conclusions drawn from the research are that the characteristic of the waterjet power absorptiondoes not present uniqueness, and it will be affected by the ship speed after installed on board a vessel, but such an influenceon the characteristic of the waterjet power absorptionby ship speed is not as remarkableas that in the propeller′s propulsion. A ratiocinationfrom the conclusions is gotten that the prime mover in waterjet propulsion will not be overloaded in matching of hull-waterjet-engine and in service.