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Design of contracted and tip loaded propellers by using boundary element methods and optimization algorithms

Author(s): 
Stefano Gaggeroa, Juan Gonzalez-Adalidb, Mariano Perez Sobrino (University of Genoa, Sistemar)

CHALLENGE - The design of marine propellers is driven by the enhancement of efficiency to reduce fuel consumption and emissions. New types of propellers have been studied to increase performances, in this paper a methodology to design and optimize contracted and tip-loaded (CLT) propellers is proposed.

SOLUTION - The performances of the propeller are evaluated using an in-house Panel Method/Boundary Element Method (BEM) code based on a parametric description of the propeller blade. modeFRONTIER is used to drive automatically the design process of both the endplate and the blade geometry. A genetic algorithm has been employed to perform a multi-objective optimization computing a total of 6000 designs in the first optimization and 10000 in the second.

BENEFITS - Using modeFRONTIER enabled to perform an automatic multi-objective optimization of the CLT propeller achieving a reduction of the extension of the cavity bubble. The reduction of the cavity bubble extension is beneficial also from the point of view of induced pressure pulses that achieved a 20% reduction of the first harmonic amplitude. A wide Pareto frontier was obtained although the constrained formulation of the problem.