Research on the Optimization Design of Propeller Considered the Off-designed Conditions

Abstract. In order to improve the performance of propeller，the propeller efficiency optimization method under the off-designed conditions were studied. Taking the open water efficiency around the designed velocity of parent propeller as the objective function, taking the radial distribution of pitch ratio as the optimization variables and taking the thrust and the cavitation performance of the propeller as the constraints and the optimization mathematical model was established. The panel method was used to solve the hydrodynamic performance of propeller and the cavitation performance was described by the BaiLiEr merchant margin line. Based on the simple genetic algorithm, the optimized radial distribution of the pitch ratio was solved. The optimized results show that due to the changes of ship speed the method which takes the efficiency of design velocity as the objective function fails to achieve the expected energy-saving. And the multiple operating points corresponding efficiency around designed speed was supposed to considered