Characteristic Research On Slewing Hydraulic System Of Wing-sail

With the entry into force of Energy Efficiency Design Index (EEDI) and Ship Energy Efficiency Management Plan (SEEMP), the shipping industry needs to find solutions, like clean energy, to reduce CO2emission for vessels. Offshore wind is a clean, reproducible, and abundant resource, once abandoned; it is reappraised by human again. Therefore, modern sail-assisted technology emerged.When sailing, the wing-sail needs to adjust to the optimal attack angle according to the change of wind direction and ship course. Thus, a steady operation of wing-sail slewing mechanism is needed. Although sail-assisted technology has been developed for decades, research on slewing hydraulic system of wing-sail is seldom studied. Therefore, it is necessary to design a wing-sail slewing hydraulic system and to study the characteristics of it.In the first part, this thesis selects high lift-drag ratio multi-element wing as target sail and chooses bulk carrier "Wenzhuhai" as target ship, the area of wing-sail is determined, as well as the aerodynamics characteristic of wing-sail. In the second part, according to the actual operating feature of wing-sail, the form of slewing mechanism is designed. By comparing different types of hydraulic system, open circuit is chosen to be the form of hydraulic system. In the third part, the paper calculates the loads of slewing bearing and selects appropriate slewing bearing. Then, through force analysis of wing-sail, the gyroscopic moment is calculated and main devices of hydraulic system are selected. In the fourth part, the focus of the paper, slewing hydraulic system simulation model is established in AMESim. In the simulation model, the characteristic analysis of different moments on hydraulic system is made. From the view of control system, study of different control strategies on system characteristics is done. Finally, model of dynamic pressure damper, which improve the damping of the hydraulic system and lower the pressure fluctuation, is set up by AMESim to improve the stability and reliability of hydraulic system.This paper successfully designs a sail slewing hydraulic system, and studies its dynamic characteristic. The results show:the hydraulic slewing system can meet the requirements of Wing-sail; the moment of wind resistance, the heeling moment and the moment of inertia have larger influence on system characteristics than the friction moment; sinusoidal control signal of proportional velocity regulating valve can significantly reduce the system pressure fluctuations, it is suitable for the hydraulic system with2s of braking time and starting time; the installation of dynamic pressure damper can play good effect in pressure regulation. All of the research results provide theoretical foundation for further study to the slewing hydraulic system and control strategy.