A study on the design methodologies of propeller root fillet surfaces having nT-T/m section

Abstract

The blade root fillets which are the mechanical parts for a smooth connection surface between a propeller blade and a flange, have strong influences on the performance of propellers from both structural and hydrodynamic points of view. A few related studies (Sabol, 1983; Kennedy, et al., 1997) have issued that 3T-T/3 double radius section design would be more suitable for increasing CIS (Cavitation Inception Speed). However, all surfaces used at the experiments are the simple symmetrical, constant chord, uncambered, and untwisted NACA foil section and only a planar hub and NACA hub. On the other hand, our models are designed for the real CPP (Controllable Pitch Propeller) blades and flanges, and experimented for the performance of SCF (Stress Concentration Factor) and CIS as well. All generated models are examined through the numerical finite element method and the higher-order panel method.