Development Of A CAD Utility For Marine Propeller Based On Series Charts

The design of propeller needs the perfect integration of hull,propeller and main engine.Its effectiveness is related to the rapidity and economic benefits of the target vehicle.The hydrodynamic test charts of the series propellers provide practical and reliable design data for this purpose,and have been widely used in marine industry.However,the process of drawing and tabulation manually based on the charts is complicated and cumbersome,requiring designers' experience in selecting values and multiple iterations.After completing the design of propeller elements,it is necessary to generate 3D solid(sealed)model with high-precision to connect CFD,CAE,CAM and other engineering applications.However,the 3D modeling process is complicated,it deals with a lot of offset-points and is prone to cause high error rate.Especially for those research requiring a considerable number of different models,like open water hydrodynamic tests and some optimization of propeller,the workload of propeller modeling is extremely heavy.Therefore,the computerization of propeller design and the automation of high-precision 3D modeling are of great value to improve the level of intelligent manufacturing in China's shipbuilding industry today.In this paper,a set of propeller CAD utility based on a collection of illustrative plates is developed,which can easily and quickly complete all the propeller design work from optimum element calculation to 3D model output.The utility has two parts:propeller design and modeling,The former is a form program developed by C#,and the latter is a graphical program built under Grasshopper.The utility has the functions of optimization of geometrical parameters of a propeller,proving of cavitation limitation,strength checking and pitch correction,calculation and output of blade shape,and also automatic 3D modeling.Its main feature is the parametric and modular system design.Users can customize the propeller design requirements and the 3D model elements of the propeller,while not requiring users to have superb professional knowledge.The utility is mainly aimed at small and medium shipyards or other vehicle design manufacturers,and can complete propeller design in a very high cost-effective way.The main research contents are as follows in the research of propeller design utility:the overall process design based on the end design of propeller,parametric functional module design,the computerization of design process(algorithm research),the construction of database and the automatic generation of 3D model meeting the accuracy requirements for manufacture.After realizing the whole set of the utility,the accuracy and efficiency of the utility are verified by engineering design case test.In the extended application,two cases are used to demonstrate the practicability of the utility in propeller research and design.One is a multi-objective genetic algorithm based approach to the intelligent design of propellers.The second is to discuss the generality of Kappel Propeller tip in the design of series propellers.