Hydrodynamic characteristics of a new thrust vectoring ducted propeller with slotted nozzle

Abstract

A thrust vectoring ducted propeller with slotted nozzle is a new approach for vector propulsion that can produce lateral forces and torques, leading to the ability of manipulating the autonomous underwater vehicle (AUV) for various movements. In this work, the geometric model of the thrust vectoring ducted propeller is designed based on slotted nozzle. The nozzle of the ducted propeller is slotted and then divided into several pieces. Divided auxiliary nozzles are deflected to redirect the outflow, achieving thrust vectoring. The key feature parameters of the slotted nozzle are extracted. The performance of the thrust vectoring ducted propeller is evaluated using Computational Fluid Dynamic (CFD) method. Different parameters of the slotted nozzle are set to evaluate the influence on the thrust vectoring capability of the ducted propeller. Through comparison, a thrust vectoring ducted propeller model is determined. Hydrodynamic characteristics including thrust vectoring performance, scale effect and vertical-horizontal interactions of the thrust vectoring ducted propeller are analyzed. It is shown that the ducted propeller with slotted nozzle at full capacity has a higher vector ratio and lower thrust loss than ideal tilted thruster with a maximum tilt angle of 40°. For high Reynolds (Re) number working conditions, all forces and torques including vector thrust can be nondimensionalized into hydrodynamic coefficients related to advance ratio J. At lower Re number working conditions, thrust vectoring capability improves in a certain extent. Interactions between perpendicular directions are caused by the counterclockwise rotation of the propeller. The pattern is quite clear and can be quantified. The performance of the thrust vectoring ducted propeller is verified through towing tank experiment. All the results show that the ducted propeller with slotted nozzle can be considered controllable with good thrust vectoring capability.