Effects of tip-jet on the performance of a ducted fan

摘要

Tip-jet technology has potential value for application in vertical take-off and landing or short take-off and landing concept aircraft. The main objective of this current work is to investigate the effects of the tip-jet on the performance of a ducted fan in hover. The overall flow field of the ducted fans with tip-jet was simulated by using the shear-stress transport k-omega turbulence model with a refined high-quality structured grid at various rotational speeds. The comparative analysis of the performances of the ducted fans with different tip-jet locations was carried out. The results indicate that the circulation of the blade with tip-jet is affected by the flow blockage, Coanda effect, and edge-shed vortex. These flow features were formed by the tip-jet. The fan's thrust could be augmented when the nozzle was a little farther from the blade trailing edge. However, a higher jet flow utility efficiency could be achieved when the nozzle was close to the blade trailing edge.