CFD Analysis on Propeller Performance with Propeller Boss Cap Fin

Abstract

The global price of oil, which is both finite and limited in quantity, has been rising steadily because of the increasing requirements for energy in both developing and developed countries. Furthermore, regulations have been strengthened across all industries to address global warming. Many studies of hull resistance, propulsion and operation of ships have been performed to reduce fuel consumption and emissions. The present study examined the design parameters of the propeller boss cap fin (PBCF) and hub cap in improving the propeller efficiency. PBCF is the kind of hydrodynamic energy saving device which aims to reduce energy losses associated with propeller hub vortex by fitting fins to the cap of a propeller. The main principles of PBCF is breaking up hub vortex to straighten propeller wake, thus recovering the negative pressure on the cap. This reduces propeller’s rotational losses and produces negative torque to reduce propeller shaft torque and generating thrust. The study focuses on the size of the blades on boss cap and optimizing its geometry using CFD technique. Open Water Test has been modelled using dynamic meshing technology known as overset meshing. Seven variations of PBCF are modelled and tested to estimate the efficiency of the propeller. The obtained results are then compared with the simulation result with the propeller without PBCF arrangements. The propeller characteristics (without PBCF) has been initially validated using overset meshing strategy with the available experimental results. Overset mesh has been used to perform this analysis to give better control over the fluid flow. It has been observed that, the propeller with PBCF, one among seven variations is giving nearly 2.0% more efficient than the propeller without PBCF.