Distributed Electric Propulsion(DEP)aircraft use multiple electric motors to drive the propulsors,which gives potential benefits to aerodynamic-propulsion interaction.To investigate and quantify the aerodynamic-propul...Distributed Electric Propulsion(DEP)aircraft use multiple electric motors to drive the propulsors,which gives potential benefits to aerodynamic-propulsion interaction.To investigate and quantify the aerodynamic-propulsion interaction effect of the wing section,we built a DEP demonstrator with 24"high-lift"Electric Ducted Fans(EDFs)distributed along the wing’s trailing edge.This paper explores and compares the aero-propulsion coupling characteristics under various upstream speed,throttle,and EDF mounting surface deflection angles using a series of wind tunnel tests.We compare various lift-augmentation power conditions to the clean configuration without propulsion unit under the experiment condition of 15-25 m/s freestream flow and angles of attack from-4°to 16°.The comparison of computational results to the experimental results verifies the effectiveness of the computational fluid dynamic analysis method and the modeling method for the DEP configuration.The results show that the EDFs can produce significant lift increment and drag reduction simultaneously,which is accordant with the potential benefit of Boundary Layer Ingestion(BLI)at low airspeed.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
Distributed electric propulsion(DEP)uses multiple propellers driven by motors distributed along the leading edge of the wing to produce beneficial aerodynamic interactions.However,the wing will be in the sliding flow ...Distributed electric propulsion(DEP)uses multiple propellers driven by motors distributed along the leading edge of the wing to produce beneficial aerodynamic interactions.However,the wing will be in the sliding flow of the propeller and the lift and drag characteristics of the wing will change accordingly.The performance of the propeller will also be affected by the wing in its rear.In this paper,combined with wind tunnel tests,the low Reynolds aerodynamic properties of multiple DEP structures are numerically simulated by solving the Reynolds averaged Navier-Stokes(RANS)equation of multiple reference frames(MRF)or slip grid technology.The results demonstrate that the lift and drag of DEP increase in all cases,with the magnitude depending on the angle of attack(AOA)and the relative positions of propellers and wing.When the AOA is less than 16°(stall AOA),the change of lift is not affected by it.By contrast,when the AOA is greater than 16°the L/D(lift-to-drag ratio)of the DEP system increases significantly.This is because the propeller slipstream delays laminar flow separation and increases the stall AOA.At the same time,the inflow and the downwash effect,which is generated on both sides of the rotating shaft,result in the actual AOA of the wing being greater than the free flow AOA with a fluctuation distribution of the lift coefficient along the span.Also,for the propeller in the DEP,the blocking effect of the wing and the vortex of the trailing edge of the wing result in a significant increase in thrust.展开更多
基金supported by the National Natural Science Foundation of China(No.51877178)。
文摘Distributed Electric Propulsion(DEP)aircraft use multiple electric motors to drive the propulsors,which gives potential benefits to aerodynamic-propulsion interaction.To investigate and quantify the aerodynamic-propulsion interaction effect of the wing section,we built a DEP demonstrator with 24"high-lift"Electric Ducted Fans(EDFs)distributed along the wing’s trailing edge.This paper explores and compares the aero-propulsion coupling characteristics under various upstream speed,throttle,and EDF mounting surface deflection angles using a series of wind tunnel tests.We compare various lift-augmentation power conditions to the clean configuration without propulsion unit under the experiment condition of 15-25 m/s freestream flow and angles of attack from-4°to 16°.The comparison of computational results to the experimental results verifies the effectiveness of the computational fluid dynamic analysis method and the modeling method for the DEP configuration.The results show that the EDFs can produce significant lift increment and drag reduction simultaneously,which is accordant with the potential benefit of Boundary Layer Ingestion(BLI)at low airspeed.
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.
基金This work is supported by the National Natural Science Foundation of China(No.51505087)the Fujian Provincial Industrial Robot Basic Components Technology Research and Development Center(No.2014H2004),China.
文摘Distributed electric propulsion(DEP)uses multiple propellers driven by motors distributed along the leading edge of the wing to produce beneficial aerodynamic interactions.However,the wing will be in the sliding flow of the propeller and the lift and drag characteristics of the wing will change accordingly.The performance of the propeller will also be affected by the wing in its rear.In this paper,combined with wind tunnel tests,the low Reynolds aerodynamic properties of multiple DEP structures are numerically simulated by solving the Reynolds averaged Navier-Stokes(RANS)equation of multiple reference frames(MRF)or slip grid technology.The results demonstrate that the lift and drag of DEP increase in all cases,with the magnitude depending on the angle of attack(AOA)and the relative positions of propellers and wing.When the AOA is less than 16°(stall AOA),the change of lift is not affected by it.By contrast,when the AOA is greater than 16°the L/D(lift-to-drag ratio)of the DEP system increases significantly.This is because the propeller slipstream delays laminar flow separation and increases the stall AOA.At the same time,the inflow and the downwash effect,which is generated on both sides of the rotating shaft,result in the actual AOA of the wing being greater than the free flow AOA with a fluctuation distribution of the lift coefficient along the span.Also,for the propeller in the DEP,the blocking effect of the wing and the vortex of the trailing edge of the wing result in a significant increase in thrust.
