Ducted Propeller Optimized Design

The design of the ducted fan applied for WIG Craft (Wing In Ground Craft) is discussed in this thesis. Instead of propeller, the ducted fan is designed as a propulsor of small WIG Craft. This will not only satisfy the demand of thrust at take-off but also prevent the propeller tips disturbed by water. WIG Craft differs from aircraft, it possesses the low cruising speed. So far there is less research work on it domestically.The present paper discusses how to design a numerical model calculating the vortices of ducted fan blades, based on the classical slip theory of Theodorsen, Kutta conditions and vortices induced equations. Then this vortices model is applied in the optimum propeller design method instead of the Prandtl momentum loss factor. Finally, based on the overseas" data of propeller and duct, educe all of the geometry parameters of the propellers and the duct.In the whole design process, the free propeller design method based on the minimum energy loss is extended to the ducted fan design, it is the first try for the set-up of the ducted fan design method.