The Motion Simulation Of Waterjet Ship And Numerical Simulation Of Waterjet Inlet Pipe Flow Field

Water jet propulsion has the advantages of high efficiency, high control performance, strong anti cavitation ability, low vibration and low noise, suitable for shallow water navigation and so on. Water jet propulsion is widely applied to all types of ships, and has brought huge commercial interests. However, some problems in the technology of water jet propulsion are still not solved perfectly, and there are some shortcomings in the theory and in the design and manufacture. The purpose of this paper is to provide the basis and suggestion for the establishment of the high reliability of the ship motion model and the design of the water supply pipeline with good and low cavitation.In this paper, the pressure a nd velocity distribution of the MMG model based on the propeller driven by the water jet propulsion system and the pressure and velocity distribution in the inlet duct are studied. The three degree of freedom motion model of the water jet propulsion ship is established, and the influence of inertia force and viscous force on the ship hull under different working conditions is analyzed. The relationship between the flow velocity of the nozzle and the shaft power, and the calculation formula of the thrust and the backing force are derived. According to the model, the double jet propulsion ship motion simulation is carried out, the simulation results obtained from the ship motion, reversing rotary motion and Z type steering motion, and compared with the available experimental data. The simulation results show that the model of the separated MMG ship motion model is also applicable to the water jet propulsion. The use of K-ε and RNG K-ε Fluent model, by setting the boundary conditions and calculation parameters for numerical simulation of spray pipe flow under various conditions, obtained distribution of pressure and velocity in the flow field. Simulation results show that the pipeline lip and slope area prone to cavitation, water ratio is a key factor affecting the velocity and pressure distribution of pipeline.