Study Of Energy-Saving Rudder-Bulb-Fin Combination Behind Propeller

The thesis is concentrated on the rudder-bulb-fin system which is a simple energy-saving assembly device. As fuel prices continuously raise, all countries speed up the pace of the ship energy-saving technology. With lost cost, easy installation and etc, hydrodynamic additional energy-saving devices have been proved to have clear benefits. To improve the energy-saving effect of the devices, energy-saving assembly device were put forward.The surface panel method theory was introduced in the thesis, which is to calculate propeller,3d rudder performance and induced velocity field. The steady interference in uniform flow between propeller and rudder was considered by induced velocity superposition. The hydrodynamic performance of propeller-rudder-bulb system was predicted by the method deduced from propeller-rudder system. Comparing with experiment results, availability is testified for numerical calculation mentioned in this paper. The energy-saving effect of propeller-rudder-bulb-fin system was predicted based on the method of propeller-rudder-bulb system, of which fins were installed on bulb. Changing dimensions, this paper studied the principal parameters (rudder-bulb size, fin size and installation angle) that affect energy-saving effect. Theoretical studies have shown that the energy-saving effect of rudder-bulb-fin is better than rudder-bulb; Fin and bulb sizes have more significant effects on energy saving effect than the installation angle of fins; These fins before rudder will provide additional thrust and improve flow field of rudder; When the rudder and fins produce a total maximum additional thrust, the rudder-bulb-fin system has the best energy-saving effect.