Study On The Propeller Load Simulation Of The Marine Hydraulic Propulsion System

The ship hydraulic propulsion refers to a new kind of marine power plant that the hydraulic pumps driven by one or more diesel engines pump the hydraulic oil to hydraulic motor which drives the propeller through the hydraulic pipes and valves to realize the movement of the ship. Namely the power from the diesel engines is passed to the propellers by hydraulic oil in the process. Hydraulic transmission has the advantages such as higher power mass ratio, better safety performance, making the ship hydraulic propulsion become an excellent ship propulsion. Ship propeller plays an important role as a thruster in the hydraulic propulsion system, the study on Propeller Load Simulation will play a catalyst role in the technology application of the ship hydraulic propulsion.In this paper, based on the marine hydraulic propulsion experimental apparatus developed by Ship Electromechanical Products Supporting R&D Center in Dalian, the basic principles and components of the marine hydraulic propulsion experimental apparatus were introduced. Combined with specific experiment, the defect hydraulic motor speed control mode in the current experimental device was pointed out, and then the closed-loop control strategy based on the actual speed of the hydraulic motor was given. Because of the current loading system cannot meet the requirements of the ship hydraulic propulsion bidirectional loading, the bidirectional loading scheme of the ship hydraulic propulsion experimental apparatus was put forward. In order to make the loading system to achieve propeller load characteristics, all condition of paddle mathematical model was derived through the analysis of the characteristics of the propeller load. Combined with the ship hydraulic propulsion two-way loading scheme, the propeller load simulation control strategy was presented. Namely through real-time acquisition of the output signal of the hydraulic motor speed (propeller speed), the actual torque propeller calculated by paddle model was used as given torque for the loading pump. Then the marine hydraulic propulsion system simulation model was built by LMS AMESim software which is on the principle of system oriented modeling, the paddle model was established by using Simulink simulation tool, combined the marine hydraulic propulsion model and load model, the whole simulation model was completed. The simulation results show that the hydraulic propulsion load simulation system can simulate well the actual propeller torque of various conditions. It is concluded that some basic rules of operating the marine hydraulic propulsion according to the pressure changes of hydraulic propulsion system in the ship sailing and inverted flight conditions.