Effect of Blade Number on Open Water Performance of Ducted Propeller

In order to study the relationship between the number of blades and thrust, torque and open water efficiency of ducted propeller, the hydrodynamic characteristics of ducted propeller with different number of blades were analyzed by computational fluid dynamics method. A numerical model is established, and the relative motion between the propeller and the duct is realized by using the structured grid and the moving multi-reference frame. The hydrodynamic performance of JD7704+Ka4-55 ducted propeller is analyzed as an example, and the rationality of the model is verified by comparing the numerical results with the experimental results. The effects of different blade numbers on the hydrodynamic characteristics of ducted propellers were studied by numerical method, and the open water performance curves of JD7704 duct and Ka3-55 and Ka5-55 propellers were obtained. The results show that the Ka4-55+JD7704 propeller has a better fit with the duct when the advance ratio is low, and the propulsion efficiency and thrust coefficient are high. When the advance ratio coefficient is large, the Ka5-55+JD7704 propeller and the duct are more suitable, because the propulsion efficiency is higher, and the thrust coefficient is higher.