An Optimization Framework for PBCF Energy Saving Devices

The need of continuously improving propulsive efficiency encourages the development of energy saving devices, the understanding of their underlying principles and the validation of their effectiveness. In this work, a design by optimization of Propeller Boss Cap Fin (PBCF) devices is carried out using Computational Fluid Dynamics analyses. RANS calculations (by the OpenFOAM library) are applied in an automatic optimization design approach involving a parametric description of the main characteristics of PBCFs. The optimization is carried out with multiple purposes: identify a reliable design strategy necessary to customize the PBCF geometry based on the propeller functioning and evaluate the influence of alternative configurations and of main geometrical parameters in achieving higher efficiency. The use of high-fidelity RANS calculations confirm that the decrease of the hub vortex strength, the reduction of the net torque and the influence of the additional fins on blades performance are the major contributors to the increase of efficiency. Results of detailed analyses of optimal PBCF configurations show model scale increases of efficiency of about 1%.