Development of a Toroidal Propeller for Marine Applications

Abstract

Toroidal propellers have demonstrated promise for increased efficiency and reduced cavitation in an aerial environment, particularly in small-scale applications such as unmanned aerial vehicles. However, there is limited research on their performance in a marine environment. To address this gap, we developed a methodology to design marine toroidal propellers with an expanded area ratio (EAR) equivalent to that of a traditional screw propeller. The toroidal propeller geometry is parametrically varied by blade reference line and blade angle modifications to attempt to achieve an efficiency identical to the screw propeller. Using computational fluid dynamics (CFD), the baseline screw propeller and toroidal propeller geometries were simulated in identical marine environments, which were validated against experimental data. Thrust, torque, and efficiency were compared to assess effective parametric variation. This provides a process for evaluating toroidal propeller applications and contributes to a better understanding of how toroidal propellers behave in marine environments. CFD results revealed that toroidal propellers require a higher torque and produce a higher thrust than traditional screw propellers. A careful variation of propeller parameters is needed to balance torque and thrust for a noticeable increase in efficiency.