This paper presents the theoretic and numerical background of a recent patent about an innovative Coanda Effect application. This innovative jet is designed to enhance the controllability of the system and to encompass static deflection of the fluid jet but especially the dynamic variation of the Coanda deflection with a very low inertia. This innovative nozzle is formerly named H.O.M.E.R., acronym of “High-speed Orienting Momentum with Enhanced Reversibility”. H.O.M.E.R. constitutes an application based on a dual propeller system. It explains how a vector controllable flux can be produced, with the ability to change angular position dynamically as a function of momentum (or velocity) of the two primitive streams. CFD based simulation in a configuration is provided and main calculations are produced to define the control model. Nozzle design guidelines are provided. The proposed system can be used both for aeronautical naval propulsion and industrial applications
Abstract:The advantages associated to Vertical Short-Take-Off and Landing (V/STOL) have been demonstrated since the early days of aviation, with the initial technolology being based on airships and later on helicopters and planes. Its operational advantages are enormous, being it in the field of military, humanitarian and rescue operations, or even in general aviation. Helicopters have limits in their maximum horizontal speed and classic V/STOL airplanes have problems associated with their large weight, due to the implementation of moving elements, when based on tilting rotors or turbojet vector mechanical oriented nozzles. A new alternative is proposed within the European Union Project ACHEON (Aerial Coanda High Efficiency Orienting-jet Nozzle). The project introduces a novel scheme to orient the jet that is free of moving elements. This is based on a Coanda effect nozzle supported in two fluid streams, also incorporating boundary layer plasma actuators to achieve larger deflection angles. Herein we introduce a state-of-the-art review of the concepts that have been proposed in the framework of jet orienting propulsion systems. This review allows to demonstrate the advantages of the new concept in comparison to competing technologies in use at present day, or of competing technologies under development worldwide.
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
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