The EU-funded project ACHEON (Aerial Coanda high efficiency orienting-jet nozzle) produced a system that will significantly impact industrial innovation. Four universities, one technology transfer organisation together with a research-intensive small to medium-sized enterprise developed a new technology that overcomes the limitations of traditional propulsion systems. The main advantage of the ACHEON system is its ability to produce thrust without the movement of mechanical parts by exploiting fluid dynamic effects. Specifically, the new concept is based on the combination of a high-speed orienting momentum with enhanced reversibility (HOMER) nozzle and a plasma enhanced actuator for Coanda effect (PEACE). The HOMER nozzle is designed to utilise its own geometry to control the direction of a synthetic jet created by the mixture of two high speed air streams. It is exploiting the tendency of a fluid jet to adhere to a curved surface because of the reduced pressure produced by high velocity. The principle is named after the Romanian aerodynamics pioneer Henri Coanda that recognised its practical applications in aircraft design. The PEACE actuator ensures active control of Coanda adhesion using dielectric barrier discharge technology. When high voltage (of several kilovolts) is applied to two electrodes – one exposed to the air and the other fully covered by a dielectric material – air in the proximity of the surface is accelerated. Different air vehicle architectures were tested and validated through computational fluid dynamics simulations. The most promising solutions were then implemented to obtain operational experience. In particular, various nozzle designs were tested to demonstrate that a propulsion system with direction control of the air jet is realisable. A very advanced concept that was intuited more than a century ago couldn't be applied because of the absence of an effective jet vectoring system. With the funding of the ACHEON project, researchers explored a radically new propulsion concept and proved its viability. Although the ACHEON system can be utilised with current jet technologies, it is expected to be the enabling technology for all-electric aircraft in the near future.
Propulsion, plasma enhanced actuator, HOMER, Coanda effect, PEACE actuator, computational fluid dynamics