A Study of Hydraulic Design of a Ducted Azimuth Thruster

Abstract

In order to obtain sufficient towing force, tug boats are usually equipped with high powered engines and special thrusters such as azimuth thrusters. The hydraulic design of a ducted azimuth thruster was carried out for a 2 MW-class tug boat by using CFD. Here, the azimuth thruster consists of a fixed-pitch screw propeller, a duct, a gear casing and a strut. To design the duct propeller, the effects of design parameters of a screw propeller and a nozzle on thruster performance were evaluated. The proper section shape of the strut is also important because it can largely affect inflow velocity distribution on the propeller. The model of the designed azimuth thruster was manufactured with a scale ratio of 10. Propeller open water and cavitation observation tests were carried out to confirm the performance of the design model.