In this paper, sensitivity approaches are taken to analyze and design an integrated flight propulsion control system where the interaction between subsystems direitly affects the stability property and handling perfor...In this paper, sensitivity approaches are taken to analyze and design an integrated flight propulsion control system where the interaction between subsystems direitly affects the stability property and handling performances of the aircraft. The eigenvalue sen sitivity approach is employed to study the effect of coupling parameters on system stability and gain sensitivity approach is used to direct the reduced states feedback suboptimal control system design. Simulation results show that the integrated flight propulsion control system designed by sensitivity approaches is of good performance.展开更多
Fundamental features of aerodynamic interference and integration of airframes and air-breathing jet engines for high-speed flight vehicles are studied within the framework of supersonic small perturbation theory.Both ...Fundamental features of aerodynamic interference and integration of airframes and air-breathing jet engines for high-speed flight vehicles are studied within the framework of supersonic small perturbation theory.Both the influence of airframe components on air intakes performance and influence of intakes on vehicle external aerodynamics are under consideration.Analytical relations and specific examples show that significant favorable interference between airframes and air intakes can be realized by using preliminary compression of the flow in front of intakes at flight Mach numbers exceeding approximately 3.展开更多
The inner rotors of distributed propulsion tilt-wing Unmanned Aerial Vehicles(UAVs)are often folded in the cruising state and deployed in vertical take-off and landing to cope with the huge difference in thrust requir...The inner rotors of distributed propulsion tilt-wing Unmanned Aerial Vehicles(UAVs)are often folded in the cruising state and deployed in vertical take-off and landing to cope with the huge difference in thrust requirements.However,the blades of the conventional rotor have poor conformality with the nacelle profile,which will greatly increase the drag of the UAV after folding.This paper proposes an integrated method for the design of rotor and nacelle considering geometric compatibility to reduce the drag of the folded rotor and nacelle,so as to further improve the aerodynamic efficiency in cruise while ensuring the rotor efficiency in the vertical flight mode.A geometric mapping model based on nacelle design parameters and rotor design parameters is established,and a parametric model and aerodynamic optimization model of the outer arc airfoil family are developed.In addition,a rotor performance analysis model and a neural network response surface model for nacelle drag prediction that meet the requirements of confidence level are established.Based on the oblique inflow blade element momentum theory method,numerical simulation method,and genetic algorithm,an integrated optimization framework of the design of the conformal rotor and nacelle is built.Then,a geometrically compatible integrated optimization for the rotor and nacelle is carried out with the objective of maximizing energy efficiency in the full mission profile.Finally,a conformal rotor and nacelle design solution is obtained,which satisfies geometric compatibility and thrust constraints while providing high thrust efficiency and low cruising drag.A comparison of the results of the integrated design and the conventional rotor optimization design shows that the drag of the conventional rotor is 3.45 times that of the conformal integrated design in the cruising state,which proves the effectiveness and necessity of the proposed method.展开更多
Aiming to maximize the aerodynamic performance of the Distributed Electric Propulsion(DEP)aircraft,a hybrid design framework which focuses on the aerodynamic performance of the propeller/wing integration has been deve...Aiming to maximize the aerodynamic performance of the Distributed Electric Propulsion(DEP)aircraft,a hybrid design framework which focuses on the aerodynamic performance of the propeller/wing integration has been developed and validated numerically.Variable-fidelity modelling for propeller aerodynamics has been used to achieve computational efficiency with reasonable accuracy.By optimizing the aerodynamic loading distributions on the tractor propeller disk,the induced slipstream is redistributed into a form that is beneficial for the wing downstream,based on which the propeller blade geometry is generated through a rapid inversed design procedure.As compared with the Minimum Induced Loss(MIL)propeller at a specified thrust level,significant improvements of both the lift-to-drag ratio of the wing and the propeller/wing integrated aerodynamic efficiency is achieved,which shows great promise to deliver aerodynamic benefits for the wing within the propeller slipstream without any additional devices.展开更多
文摘In this paper, sensitivity approaches are taken to analyze and design an integrated flight propulsion control system where the interaction between subsystems direitly affects the stability property and handling performances of the aircraft. The eigenvalue sen sitivity approach is employed to study the effect of coupling parameters on system stability and gain sensitivity approach is used to direct the reduced states feedback suboptimal control system design. Simulation results show that the integrated flight propulsion control system designed by sensitivity approaches is of good performance.
文摘Fundamental features of aerodynamic interference and integration of airframes and air-breathing jet engines for high-speed flight vehicles are studied within the framework of supersonic small perturbation theory.Both the influence of airframe components on air intakes performance and influence of intakes on vehicle external aerodynamics are under consideration.Analytical relations and specific examples show that significant favorable interference between airframes and air intakes can be realized by using preliminary compression of the flow in front of intakes at flight Mach numbers exceeding approximately 3.
基金the Fundamental Research Funds for the Central Universities(No.56XCA2205402).
文摘The inner rotors of distributed propulsion tilt-wing Unmanned Aerial Vehicles(UAVs)are often folded in the cruising state and deployed in vertical take-off and landing to cope with the huge difference in thrust requirements.However,the blades of the conventional rotor have poor conformality with the nacelle profile,which will greatly increase the drag of the UAV after folding.This paper proposes an integrated method for the design of rotor and nacelle considering geometric compatibility to reduce the drag of the folded rotor and nacelle,so as to further improve the aerodynamic efficiency in cruise while ensuring the rotor efficiency in the vertical flight mode.A geometric mapping model based on nacelle design parameters and rotor design parameters is established,and a parametric model and aerodynamic optimization model of the outer arc airfoil family are developed.In addition,a rotor performance analysis model and a neural network response surface model for nacelle drag prediction that meet the requirements of confidence level are established.Based on the oblique inflow blade element momentum theory method,numerical simulation method,and genetic algorithm,an integrated optimization framework of the design of the conformal rotor and nacelle is built.Then,a geometrically compatible integrated optimization for the rotor and nacelle is carried out with the objective of maximizing energy efficiency in the full mission profile.Finally,a conformal rotor and nacelle design solution is obtained,which satisfies geometric compatibility and thrust constraints while providing high thrust efficiency and low cruising drag.A comparison of the results of the integrated design and the conventional rotor optimization design shows that the drag of the conventional rotor is 3.45 times that of the conformal integrated design in the cruising state,which proves the effectiveness and necessity of the proposed method.
基金supported by the Key Research and Development Program of Shaanxi Province of China(No.2018ZDCXL-GY-03-04)。
文摘Aiming to maximize the aerodynamic performance of the Distributed Electric Propulsion(DEP)aircraft,a hybrid design framework which focuses on the aerodynamic performance of the propeller/wing integration has been developed and validated numerically.Variable-fidelity modelling for propeller aerodynamics has been used to achieve computational efficiency with reasonable accuracy.By optimizing the aerodynamic loading distributions on the tractor propeller disk,the induced slipstream is redistributed into a form that is beneficial for the wing downstream,based on which the propeller blade geometry is generated through a rapid inversed design procedure.As compared with the Minimum Induced Loss(MIL)propeller at a specified thrust level,significant improvements of both the lift-to-drag ratio of the wing and the propeller/wing integrated aerodynamic efficiency is achieved,which shows great promise to deliver aerodynamic benefits for the wing within the propeller slipstream without any additional devices.
