A.C.H.E.O.N.: Aerial Coanda High Efficiency Orienting-jet Nozzle 2011-01-2737

This paper analyzes the use of a recently patented 2D nozzle, which is able to produce a jet deviation depending on momentums of incoming jets and nozzle geometry. The considered nozzle architecture is a general-purpose fluid dynamic application. The research activity presented in this paper aims to verify the suitability of this nozzle architecture for aerial propulsion and in particular for small electric UAVs. This nozzle requires two primitive fluid streams, which produce a variable orientation synthetic jet. This preliminary feasibility study is related to a configuration propelled by two commercial electric turbofans for RC models and small electric UAVs. It can be used for both shortening take off and landing operations if mounted in a vertical plane and for enhancing the horizontal maneuvering if mounted on a horizontal plane. The shape of the considered nozzle has not been geometrically optimized to maximize the jet deflection. This study has investigated the possibility to produce a vector orienting and controllable jet, which can change angular position dynamically as a function of momentum (or velocity) of the two flows. Fluid dynamic parameters have been considered in terms of speed of rotation of the propellers. CFD simulations performed both in static and dynamic conditions permit to define a methodology that could help the definition of system controls. CFD simulations have produced a model describing the synthetic jet angle versus ducted fan rotational speed considering a constant mass flow through the nozzle. The dynamic behavior of the system has been considered demonstrating very low system inertia.