Tip-jet rotor system has unique potential value in the area of vertical take-off and landing (VTOL) or short take-off and landing (STOL) concept aircrafts. This paper presents the results of a computational study on ducted fans with tip-jet that could be used in V/STOL vehicles. The rotor of fan is applied two rectangular, untwisted and untampered NACA0012 blades with different kinds of tip-jet nozzles. The first kind nozzle is positioned to discharge at the tip mid chord location, removing blade back half in the downstream region; the second kind nozzle is positioned at the blade tip trailing, adjusting the airfoil profile to fit the dimension of the pipe inside the blade; and the third kind nozzle has a conformal outlet at the blade tip. The goal of this study is to obtain and to analyze the detailed flow features and performance of tip-jet ducted fans with various nozzles by CFD method. Current results show that the circulation of blade could be influence by the tip-jets discharged from the nozzle and the configuration of the nozzle. Compared to other nozzle structure presented in this paper, the performance of ducted fan with conformal nozzle is the best, for achieving the highest fan lift with the lowest bleed air conditions.
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