To enhance the propulsive efficiency of ducted propeller for better endurance of underwater-vehicle

19A/Ka4 series ducted propeller is studied through numerical simulation to analyze the factors of the duct and blade on the hydrodynamic performance by change the such parameter such as length-diameter ratio

diameter ratio

blade area ratio and pitch ratio under different mesh models. It is discovered that the length-diameter ratio has almost no influence of the open water performance

though

the cavitation performance is better with the increase of length-diameter ratio. The lesser duct diameter ratio and blade area ratio will increase the efficiency

and accordingly

the thrust coefficient and torque coefficient will decrease. The influence of the pitch ratio on ducted propeller is similar to the conventional propeller

with the increase of pitch ratio

the peak efficiency will increase until to a constant value. Based on aforementioned research in a specified range of blade area ratio and diameter ratio

it is found that the minimum blade area ratio and minor diameter ratio will generate the extreme efficiency.