Computational Fluid Dynamic Study on a Novel Propulsive System: ACHEON and Its Integration with an Unmanned Aerial Vehicle (UAV)

In the present paper, numerical investigations are carried out in a newly proposed propulsive system Aerial Coanda high-efficiency orienting jet nozzle (ACHEON), which supports thrust vectoring and its application to prototype unmanned aerial vehicles (UAVs). The ACHEON system is presently being proposed for propelling a new vertical and short takeoff (V/STOL) airplane in the European Union. This system is powered by two axial electric turbofans and uses the Coanda effect (attachment of the jet to a curved surface) to achieve precise control of the thrust angle. The present study investigates the thrust vectoring efficiency of this newly patented nozzle and its integration with UAVaircraft. This study numerically investigates the 3D effects on this new machine and proposes remedies to solve the associated problems. Further, swirling effects generated by electric turbofans were studied in great detail. The effect of uniform and nonuniform velocity profiles were investigated on thrust vectoring efficiency of the nozzle. Then, the aerodynamic features of prototype UAVs were determined under various flow conditions. The interaction of the exit nozzle flow with incoming airstream was studied. Computational fluid dynamics (CF) calculations were carried out using Reynolds averaged Navier-Stokes (RANS) equations. A numerical method based on finite volume formulation (FVM) was used. Turbulent flow is modeled by using the SST k-omega model. Numerical results show that the presence of swirling velocities in the flow field significantly affects the thrust vectoring efficiency of the nozzle. From numerical simulations of the aircraft, it was found that the aerodynamic characteristics are strongly affected by the exit air jet angle. (C) 2015 American Society of Civil Engineers.