A Procedure for Optimizing Cavitating Propeller Blades in a Given Wake

摘要

With more understanding and research on the prediction of propeller performance, it is natural for propeller designers to try to find an optimum design propeller. This problem was addressed already by Betz in 1919. Glauert combined the momentum theory and blade element theory for predicting and optimizing the efficiency of a propeller. Adkins et al extended Glauert's propeller theory by eliminating the light loading and small angle assumptions in the optimization design theory and calculated the vortex displacement velocity accurately. De Jong carried out an optimization including the viscosity effects of ship propellers with end plates. Rizk developed a scheme to update design parameters and flow variables iteratively. The accuracy, efficiency and sensitivity of the computational parameters were tested with a single equality constraint. It is possible to extend this method to solve more general optimization problems with more constraints, even of the inequality types. Triantafyllou formulated a preliminary B-series design process considering the interaction of engine, hull, wake and propeller, the fuel consumption being the optimization objective. The blade number, expanded area ratio and advance coefficient were investigated. A similar but more recent method for propeller optimization is presented by Benini. In this research a multi-objective evolutionary algorithm was used for preliminary design of a B-Screw propeller. Kinnas and Mishima applied a numerical optimization method for designing both partial and super-cavitating sections. The drag was minimized with given cavitation number and lift force. They coupled a numerical optimization technique with MPUF for the analysis and optimization of a cavitating propeller. The objective and constraints were expressed in terms of design parameters, which are movements of B-Spline control points. The method was applied on 2D partially and supercavitating hydrofoil sections, 3D propeller blades in uniform flow and cavitating blades in non-uniform flow.