• Increasing aeronautic electric propulsion performances by cogeneration and heat recovery

      Trancossi, Michele; Dumas, Antonio; Stewart, Paul; Vucinic, Dean; University of Lincoln; University of Hull (Society of Automotive Engineers, 2014)
      Emissions from aviation have become a focus of increasing interest in recent years. The growth of civil aviation is faster than nearly all other economic sectors. Increased demand has led to a higher growth rate in fossil fuels consumption by the aviation sector. Despite more fuel-effcient and less polluting turbofan and turboprop engines, the growth of air travel contributes to increase pollution attributable to aviation. Aircraft are currently the only human-made in situ generators of emissions in the upper troposphere and in the stratosphere. The depletion of the stratosphere's ozone layer by CFCs and related chemicals has underscored the importance of anticipating other potential insults to the ozone layer. Different possible solutions have been advanced to reduce the environmental impact of aviation, such as electrication of ground operations, optimization of airline timetables and airspace usage, limitation of cruise altitude and increased use of turboprop aircrafts. Those improvements seem very limited answers, which allow only marginal reduction of the environmental footprint of air transport. Breakthrough concepts such as the all-electric aircrafts must be considered. Today state of electric-propulsion is demonstrating a lack of performance and operative range if compared to traditional propulsion concepts. This paper presents a novel concept which has been only envisaged before based on the increase of the performance and range of electric airplanes by an effective cogeneration on board. This concept aims to allow effective and more efcient electric aeronautic propulsion through next generation of green all electric propulsion
    • A new aircraft architecture based on the ACHEON Coanda effect nozzle: flight model and energy evaluation

      Marques, Jose Pascoa; Porreca, Eliana; Smith, Tim; Stewart, Paul; Subhash, Maharshi; Sunol, Anna; Vucinic, Dean; Trancossi, Michele; Madonia, Mauro; Dumas, Antonio; et al. (Springer, 2016-03-12)
      Aeronautic transport has an effective necessity of reducing fuel consumption and emissions to deliver efficiency and competitiveness driven by today commercial and legislative requirements. Actual aircraft configurations scenario allows envisaging the signs of a diffused technological maturity and they seem very near their limits. This scenario clearly shows the necessity of radical innovations with particular reference to propulsion systems and to aircraftarchitecture consequently. Methods This paper presents analyses and discusses a promising propulsive architecture based on an innovative nozzle, which allows realizing the selective adhesion of two impinging streams to two facing jets to two facing Coanda surfaces. This propulsion system is known with the acronym ACHEON (Aerial Coanda High Efficiency Orienting Nozzle). This paper investigates how the application of an all-electric ACHEONs propulsion system to a very traditional commuter aircraft can improve its relevant performances. This paper considers the constraints imposed by current state-of-the-art electric motors, drives, storage and conversion systems in terms of both power/energy density and performance and considers two different aircraft configurations: one using battery only and one adopting a more sophisticated hybrid cogeneration. The necessity of producing a very solid analysis has forced to limit the deflection of the jet in a very conservative range (±15°) with respect to the horizontal. This range can be surely produced also by not optimal configurations and allow minimizing the use of DBD. From the study of general flight dynamics equations of the aircraft in two-dimensional form it has been possible to determine with a high level of accuracy the advantages that ACHEON brings in terms of reduced stall speed and of reduced take-off and landing distances. Additionally, it includes an effective energy analysis focusing on the efficiency and environmental advantages of the electric ACHEON based propulsion by assuming the today industrial grade high capacity batteries with a power density of 207 Wh/kg. Results It has been clearly demonstrated that a short flight could be possible adopting battery energy storage, and longer duration could be possible by adopting a more sophisticated cogeneration system, which is based on cogeneration from a well-known turboprop, which is mostly used in helicopter propulsion. This electric generation system can be empowered by recovering the heat and using it to increase the temperature of the jet. It is possible to transfer this considerable amount of heat to the jet by convection and direct fluid mixing. In this way, it is possible to increase the energy of the jets of an amount that allows more than recover the pressure losses in the straitening section. In this case, it is then possible to demonstrate an adequate autonomy of flight and operative range of the aircraft. The proposed architecture, which is within the limits of the most conservative results obtained, demonstrates significant additional benefits for aircraft manoeuvrability. In conclusion, this paper has presented the implantation of ACHEON on well-known traditional aircraft, verifying the suitability and effectiveness of the proposed system both in terms of endurance with a cogeneration architecture and in terms of manoeuvrability. It has demonstrated the potential of the system in terms of both takeoff and landing space requirements. Conclusions This innovation opens interesting perspectives for the future implementation of this new vector and thrust propulsion system, especially in the area of greening the aeronautic sector. It has also demonstrated that ACHEON has the potential of renovating completely a classic old aircraft configuration such as the one of Cessna 402.