Fluid dynamics optimization of a Shaft-less rim-driven propeller

Amedeo Migali, Daniele Bruno, Daniele Malgieri, Marco De Santis (MICAD Srl)

CHALLENGE - The shaft-less rim-driven propeller (RDP) can provide many advantages over traditional ship propulsion plants, including enhanced onboard comfort and propulsion efficiency, locations arrangement flexible installation, light weight and compact size. For this reason, during last years it become an attractive ship propulsion device in the marine industry.

SOLUTION - Within the project P. E. R. Na. “Propulsore elettrico reversibile per la Nautica” financed by the FvG region with Uni-TS, Uni-UD and MW.FEP as partners, a hydrodynamic optimization (DoE) was developed with the aim of determining the feasibility of this type of thrusters for propulsion of sailing boats. The electric motor will have the possibility of generating electricity by extracting energy from the boat's motion when it sails. In this preliminary study, only the propulsion phase was investigated. A completely parametric model of the rotor (blades, rim and hydrodynamics cover) has been created with Grasshopper inside the Rhinoceros 3D environment, a selection of variables has been included in the multi-objectives optimization process carried out through modeFRONTIER (ESTECO) by measuring the parameters chosen by performing CFD simulations with the Star-CCM+ solver (SIEMENS).


BENEFITS - Optimization strategy, has proved cost effective and smart in driving project towards the optimal design comparing hundreds of variants. The optimum propeller blades design has been realized through additive manufacturing in syntherized nylon, each blade was printed and consequently assembled on the engine rotor, as well the external carter. The entire device, electric engine plus propeller blades, will be tested in next months in operative conditions.