Research On Energy-Saving Characteristic Of Marine Propeller-Rudder System

With the developing of technology, the increasing demand for energy, marine energy conservation has been earned unprecedented attention. As a ship manipulation device, rudder is installed in the rear of propeller in the stern. Flow field between propeller and rudder is disturbed when the propeller is operating, and field around the propeller obtained the rotational energy. The energy wasted propulsive efficiency of propeller. It is an effective way to improve propulsive efficiency that the interference between propeller and rudder is utilized reasonably. The research methods of interference between propeller and rudder include test method, Computational Fluid Dynamics and theoretical method, and the paper choose the Boundary Element Method belongs to theoretical method. The main content includes:(1) Hydrodynamic performance is calculated by BEM after the grid model of open water propeller and open water rudder is established. The BEM method accuracy is verified by compared with test data.(2) The propulsion performance of propeller- common rudder system, propeller-twist rudder system and propeller-deformed becker rudder system is calculated and analyzed after the grid model is established.(3) The induced velocity of open water propeller and propeller- rudder system is calculated.It is found that transverse velocity is the main reason affecting the propeller- rudder system energy savings after axial velocity and transverse velocity are analyzed and compared.The paper will calculate and analysis circumferential speed because radial velocity is smaller than others.(4) Optimize twist rudder and deformed becker rudder sectional form is a great way to reduce the resistance of the rudder. Twist rudder were optimized by reducing the angle of cross-section and flow. Deformed becker rudder were optimized by changing the sectional deflection angle. The propulsion performance influence will be compared between pre-optimize and optimize.The calculations show that propeller- deformed becker rudder systemHydrodynamic performance is better than other two system.Circumferential speed is reduced due to the influence of the rudder. The decrease of circumferential speed is the main reason that rudderimprove the propulsion efficiency.The optimization for twist rudder and deformed becker rudder improve the propeller- rudder systempropulsion performance.