Adaptive,morphing flaps are taking ever-increasing attention in civil aviation thanks to the expected benefits this technology can bring at the aircraft level in terms of high-lift performance improvement and related ...Adaptive,morphing flaps are taking ever-increasing attention in civil aviation thanks to the expected benefits this technology can bring at the aircraft level in terms of high-lift performance improvement and related fuel burnt reduction per flight.Relying upon morphing capabilities,it is possible to fix a unique setting for the flap and adapt the flap shape to match the aerodynamic requirements for take-off or landing.The proper morphed shapes can assure better high-lift performances than those achievable by referring to a conventional flap.Moreover,standing the unique flap setting for take-off and landing,a dramatic simplification of the flap deployment systems may be achieved.As a consequence of this simplification,the deployment system can be fully hosted in the wing,thus avoiding under-wing nacelles with significantly better aerodynamics and fuel consumption.The first step for a rational design of an adaptive flap consists in defining the target morphed shapes and the unique optimal flap setting in the take-off and landing phases.In this work,aerodynamic optimization analyses are carried out to determine the best flap setting and related morphed shapes in compliance with the take-off and landing requirements of a reference civil transport aircraft.Four different initial conditions are adopted to avoid the optimization falling into local optima,thus obtaining four groups of optimal candidate configurations.After comparing each candidate’s performance through 2D and 3D simulations,the optimal configuration has been selected.2D simulations show that the optimal configuration is characterized by a maximum lift increase of 31.92%in take-off and 9.04%in landing.According to 3D simulations,the rise in maximum lift equals 22.26%in take-off and 3.50%in landing.Numerical results are finally verified through wind tunnel tests,and the aerodynamic mechanism behind the obtained improvements is explained by carefully analyzing the flow field around the flap.展开更多
The potential benefits of hybrid-electric or all-electric propulsion have led to a growing interest in this topic over the past decade.Preliminary design of propulsion systems and innovative configurations has been ex...The potential benefits of hybrid-electric or all-electric propulsion have led to a growing interest in this topic over the past decade.Preliminary design of propulsion systems and innovative configurations has been extensively discussed in literature,but steps towards higher levels of technological readiness,optimisation algorithms based on reliable weight estimation and simulationbased mission analysis are required.This paper focuses on the integration of a method for evaluating the lateral-directional controllability of an aircraft within a design chain that integrates aero-propulsive interactions,accurate modelling of the fuel system,and mid-fidelity estimation of the structural weight.Furthermore,the present work proposes a strategy for powerplant management in scenarios with an inoperative chain element.Benefits of hybrid-electric propulsion on the design of the vertical tail plane are evaluated involving the analysis of multiple failure scenarios and certification requirements.The proposed application concerns a commuter aircraft.展开更多
This paper presents the power-off, lateral-directional wind tunnel tests on the fixedwing, 19-passenger aircraft model developed within the Italian PROSIB project. The concept is an innovative small air transport airp...This paper presents the power-off, lateral-directional wind tunnel tests on the fixedwing, 19-passenger aircraft model developed within the Italian PROSIB project. The concept is an innovative small air transport airplane with distributed propellers and hybrid-electric powerplant. By measuring the aerodynamic forces and moments, the experimental investigation focused on the estimation of the power-off stability and control derivatives, highlighting the effects of the aerodynamic interference. Tests included a belly-mounted pod, simulating a battery storage unit, and two distinct empennage configurations: a body-mounted(low) horizontal tail and a T-tail(high). Numerical analyses were also used to further highlight the role of aerodynamic interference in the generation of forces and moments. For instance, wind tunnel data have shown a beneficial effect of the belly pod on the aircraft directional stability(+13%), but were in contrast with the results of numerical analyses(-30%). The measured sidewash depends also from the empennage layout, not only from the vertical tail planform area. Simulations confirmed an excessive directional stability with respect to the directional control in the ratio of 1.65, suggesting that such class of airplane should have a larger rudder chord ratio or a horn balance. Combined tests at different angles of attack and flap deflections revealed some issues on the lateral stability of the model, which are related to the velocity circulation on the wing in high-lift conditions counteracting the effective dihedral of the model's layout. The collected dataset of aerodynamic derivatives will serve as reference for a next experimental investigation on the aero-propulsive effects and provide useful information to researchers and professionals involved in similar design studies.展开更多
基金co-supported by the National Natural Science Foundation of China (Nos. 12172275, 12090030)the “111” Program, China (No. B18040)
文摘Adaptive,morphing flaps are taking ever-increasing attention in civil aviation thanks to the expected benefits this technology can bring at the aircraft level in terms of high-lift performance improvement and related fuel burnt reduction per flight.Relying upon morphing capabilities,it is possible to fix a unique setting for the flap and adapt the flap shape to match the aerodynamic requirements for take-off or landing.The proper morphed shapes can assure better high-lift performances than those achievable by referring to a conventional flap.Moreover,standing the unique flap setting for take-off and landing,a dramatic simplification of the flap deployment systems may be achieved.As a consequence of this simplification,the deployment system can be fully hosted in the wing,thus avoiding under-wing nacelles with significantly better aerodynamics and fuel consumption.The first step for a rational design of an adaptive flap consists in defining the target morphed shapes and the unique optimal flap setting in the take-off and landing phases.In this work,aerodynamic optimization analyses are carried out to determine the best flap setting and related morphed shapes in compliance with the take-off and landing requirements of a reference civil transport aircraft.Four different initial conditions are adopted to avoid the optimization falling into local optima,thus obtaining four groups of optimal candidate configurations.After comparing each candidate’s performance through 2D and 3D simulations,the optimal configuration has been selected.2D simulations show that the optimal configuration is characterized by a maximum lift increase of 31.92%in take-off and 9.04%in landing.According to 3D simulations,the rise in maximum lift equals 22.26%in take-off and 3.50%in landing.Numerical results are finally verified through wind tunnel tests,and the aerodynamic mechanism behind the obtained improvements is explained by carefully analyzing the flow field around the flap.
基金The ELICA project leading to this application has received funding from the Clean Sky 2 Joint Undertaking(JU)(No.864551)The JU receives support from the European Union’s Horizon 2020 research and innovation programme。
文摘The potential benefits of hybrid-electric or all-electric propulsion have led to a growing interest in this topic over the past decade.Preliminary design of propulsion systems and innovative configurations has been extensively discussed in literature,but steps towards higher levels of technological readiness,optimisation algorithms based on reliable weight estimation and simulationbased mission analysis are required.This paper focuses on the integration of a method for evaluating the lateral-directional controllability of an aircraft within a design chain that integrates aero-propulsive interactions,accurate modelling of the fuel system,and mid-fidelity estimation of the structural weight.Furthermore,the present work proposes a strategy for powerplant management in scenarios with an inoperative chain element.Benefits of hybrid-electric propulsion on the design of the vertical tail plane are evaluated involving the analysis of multiple failure scenarios and certification requirements.The proposed application concerns a commuter aircraft.
基金funded by the Italian PROSIB (Propulsione e Sistemi Ibridi per velivoli ad ala fissa e rotante-Hybrid Propulsion and Systems for fixed and rotary wing aircraft) project PNR 2015-2020 ARS01_00297 led by Leonardo S.p.A
文摘This paper presents the power-off, lateral-directional wind tunnel tests on the fixedwing, 19-passenger aircraft model developed within the Italian PROSIB project. The concept is an innovative small air transport airplane with distributed propellers and hybrid-electric powerplant. By measuring the aerodynamic forces and moments, the experimental investigation focused on the estimation of the power-off stability and control derivatives, highlighting the effects of the aerodynamic interference. Tests included a belly-mounted pod, simulating a battery storage unit, and two distinct empennage configurations: a body-mounted(low) horizontal tail and a T-tail(high). Numerical analyses were also used to further highlight the role of aerodynamic interference in the generation of forces and moments. For instance, wind tunnel data have shown a beneficial effect of the belly pod on the aircraft directional stability(+13%), but were in contrast with the results of numerical analyses(-30%). The measured sidewash depends also from the empennage layout, not only from the vertical tail planform area. Simulations confirmed an excessive directional stability with respect to the directional control in the ratio of 1.65, suggesting that such class of airplane should have a larger rudder chord ratio or a horn balance. Combined tests at different angles of attack and flap deflections revealed some issues on the lateral stability of the model, which are related to the velocity circulation on the wing in high-lift conditions counteracting the effective dihedral of the model's layout. The collected dataset of aerodynamic derivatives will serve as reference for a next experimental investigation on the aero-propulsive effects and provide useful information to researchers and professionals involved in similar design studies.
