Simulation Research On Main Engine Acceleration Performance Of Waterjet Propulsion System

Waterjet propulsion has become an important research object around the world since the1950s at ship industry. Now, it is the preferred method for High-performance ship and gainrapid development and wide application in both the civilian and military aspects.It haspositive significance for the design and application of waterjet system to reveals the inherentmechanism and study the steady-state and dynamic process based on modeling andsimulation.This paper launch it’s work from water-jet propulsion system structure, to simulatingfault state by using the mathematical model which has been established and validated.Atfirst,the working principle,development,as well as domestic and foreign research status of jetpropulsion technology have been outlined. Sequential Turbocharged Diesel model, dieselspeed control model and jet pump model has been built respectively in AMESim andSimulink based on a certain type ship.Secondly, according to the diesel engine factory testingand navigation data, the diesel model and entire system model has been calibrated. Finally,acceleration performance and turbocharger failure impaction have been researched in the formof AMESim and Simulink co-simulation.First of all, to meet the requirements of the maximum acceleration mobility,themaximum acceleration rate of four pump mode has been stimulated under the limitation ofdiesel load limit,acceleration rate as well as water-jet pump cavitation.Secondly,Due to thedecrease of the total thrust,the ship’s acceleration process is slow.the highest Diesel Enginespeed has been calculated to avoid the cavitation restricted zone of water-jet pump under twomachines-two pump mode.Considering the host does not give full play to its power under thissitutation, this paper discussed the possiblity of Segmented acceleration and Reduction of thespeed rate.The results failed to improve the acceleration process.At last,the host loadlimitation, the rack displacement constraints and cycle fuel injection quantity limitation havebeen received under supercharger fault state.Turbocharger failure not only reduces theultimate ship speed, but also make the water-jet pump work under cavitation restricted zoneat the end of the acceleration process.Therefore, the acceleration time should be extended.