Design of High Wing Loading Compact Electric Airplane Utilizing Co-Flow Jet Flow Control

Lefebvre, Alexis; Zha, Gecheng

doi:10.2514/6.2015-0772

Cited by 28 publications

(17 citation statements)

References 15 publications

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“…Recently, a promising ZNMF coflow jet (CFJ) flow-control airfoil developed by Zha et al [7,[12][13][14][15][16][17][18][19] achieved a radical lift augmentation, drag reduction, and stall margin increase at a low energy expenditure [7,17]. In addition to augmenting the maximum lift coefficient with increased circulation and high-stall AoA, the CFJ airfoil also is shown to have a very appealing feature: it could significantly increase the airfoil lift coefficient and aerodynamic efficiency at cruise condition with low AoA from the subsonic to transonic regime [20][21][22]. This superior advantage at cruise condition so far is demonstrated mostly by numerical simulation [20][21][22].…”

Section: Introductionmentioning

confidence: 99%

Performance and Energy Expenditure of Coflow Jet Airfoil with Variation of Mach Number

Lefebvre

Dano

Bartow

et al. 2016

Journal of Aircraft

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This paper conducts a numerical and experimental investigation of a coflow jet airfoil to quantify lift enhancement, drag reduction, and energy expenditure at a Mach number range from 0.03 to 0.4. The jet momentum coefficient is held constant at 0.08, and the angle of attack varies from 0 to 30 deg. The two-dimensional flow is simulated using a Reynolds-averaged Navier-Stokes solver with a fifth-order-weighted essentially non-oscillatory scheme for the inviscid flux and a fourth-order central differencing for the viscous terms. Turbulence is simulated with the one equation Spalart-Allmaras model. The predicted coflow jet pumping power has an excellent agreement with the experiment. At a constant Mach number, the power coefficient is decreased when the angle of attack is increased from 0 to 15 deg. When the Mach number is increased from 0.03 to 0.3, the suction effect behind the airfoil leading edge is further augmented due to the compressibility effect. This results in an increased maximum lift coefficient and reduced power coefficient at the higher Mach number because of the lower jet-injection pumping pressure required. At Mach 0.4, the lift coefficient is further improved. However as the angle of attack is increased, a λ shock wave interrupts the jet and triggers the boundary layer separation with increased drag and power coefficient. A corrected aerodynamic efficiency that includes the coflow-jet pumping power is introduced. Because of the high lift coefficient and low coflowjet power required, the coflow-jet airfoil in this study achieves a comparable peak aerodynamic efficiency to the baseline airfoil, but the lift coefficient at peak efficiency is substantially increased by 120%. This study indicates that the coflow-jet airfoil is not only able to achieve very high maximum lift coefficient, but also able to improve cruise performance at low angle of attack when the flow is benign.

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Section: Introductionmentioning

confidence: 99%

Performance and Energy Expenditure of Coflow Jet Airfoil with Variation of Mach Number

Lefebvre

Dano

Bartow

et al. 2016

Journal of Aircraft

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“…The previous subsonic CFJ airfoil designs 16,18,21,36 create the suction slot opening mostly normal to the local suction surface. Under this condition, the suction slot reactionary force contributes significantly to the drag due to ram effect as indicated by Equation (1) and Equation (2).…”

Section: Iiib2 Cfj Suction Slot Opening Anglementioning

confidence: 99%

“…The previous subsonic CFJ 16,18,21,36 airfoil configurations create the injection and suction slots by translating the suction surface slightly downward. Such suction surface translation(SST) may not affect subsonic flows much, but appears to be very sensitive in transonic regime to affect the shock position and the airfoil performance.…”

Section: Iiib1 Airfoil Suction Surface Translationmentioning

confidence: 99%

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Transonic Airfoil Performance Enhancement Using Co-Flow Jet Active Flow Control

Liu

Zha

2016

8th AIAA Flow Control Conference

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This paper performs a numerical proof of concept study to enhance transonic supercritical airfoil cruise performance using Co-Flow Jet(CFJ) active flow control technique. The Reynolds averaged Navier-Stokes(RANS) equations with one-equation Spalart-Allmaras turbulence model is used. A 5th order weighted essentially non-oscillatory(WENO) scheme with a low diffusion Riemann solver is utilized to evaluate the inviscid fluxes. A 4th order central differencing scheme matching the stencil width of the WENO scheme is employed for the viscous terms. Numerical trade studies are carried out to investigate the CFJ geometric effects on the performance enhancement. This research discovers that CFJ can significantly enhance the aerodynamic performance of RAE2822 transonic supercritical airfoil for both lift coefficient CL and aerodynamic efficiency ( L D )c that includes the CFJ pumping power. For the free-stream condition of M∞=0.729, Re∞=6.5 × 10 6 , and AoA from 0 • to 5.5 • , the CFJ RAE2822 airfoil is able to achieve a performance enhancement with both CL and ( L D )c increased simultaneously by 18.7% and 14.5%, respectively at the peak aerodynamic efficiency point. At the maximum lift coefficient point, the CFJ airfoil is able to increase the CL from 0.93 to 1.16 by 25.6% while slight decreasing the ( L D )c from 21.3 to 19.6. Rigorous mesh refinement study is conducted to ensure solution convergence of the numerical results. Since the baseline airfoil drag is over-predicted by more than 30% due to the inadequacy of the RANS model, the predicted improvement of the CFJ airfoil tends to be on the conservative side. The unique feature of CFJ airfoil to augment lift and reduce drag at low energy expenditure is shown to be able to drastically improve the transonic airfoil cruise performance when the flow is benign at low AoA. The performance enhancement of CFJ transonic airfoil needs to be further proved by wind tunnel experiment as the next step. It is hoped that this research will open a door to significantly enhance transonic airfoil performance since the supercritical airfoil was invented in 1960's.

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“…However, those studies [8][9][10][11][12][13][14][15][16][17] have not report sufficient results on energy expenditure of the sweeping jets actuators, which tend to suffer large energy loss due to jet sweeping, turning, and flow separation. This paper explores a new control surfaces active flow control using Co-Flow Jet (CFJ) airfoil, which is a zero-net mass flux (ZNMF) flow control that has demonstrated radical lift enhancement, drag reduction, and ultra-high stall AoA [2,5,18,19,20,21,22,23,24,25,26,27]. Furthermore, the energy expenditure of the CFJ airfoil is very low [5,18,23].…”

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confidence: 99%

Aircraft Control Surfaces Using Co-flow Jet Active Flow Control Airfoil

Zhang

Yang

et al. 2018

2018 Applied Aerodynamics Conference

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This paper investigates the effects using high lift zero-net mass-flux Co-Flow Jet (CFJ) active flow control airfoil for aircraft control surfaces with plain flaps and with no flap. The goal is to reduce the size and weight of conventional aircraft control surfaces and save energy expenditure.Two-dimensional simulation of NACA 0012 airfoil used as a control surface is conducted for parametric trade study using a Reynolds-averaged Navier-Stokes (RANS) solver with Spalart-Allmaras (SA) model. A 5th order WENO scheme for the inviscid flux and a 4th order central differencing for the viscous terms are used to resolve the Navier-Stokes equations.The 2D numerical studies indicate that the CFJ airfoil for aircraft control surfaces with a plain flap can dramatically increase the lift coefficient and aerodynamic efficiency simultaneously compared with the conventional control surface with the same size of flap and deflection angle. CFJ airfoil control surface shows great potential to substantially reduce the size and weight of conventional aircraft control surfaces with high control authority.A series of trade study is done based on NACA0012 airfoil for control surface. The CFJ airfoil is modified from the baseline NACA0012 airfoil by translating the upper surface downward by 0.1%C. A constant deflection angle of 30° is used.The final preferred configuration has the flap length of 35%C, deflection angle of 30°, injection location at 2%C from leading edge, injection slot size of 0.5%C, and suction slot right upstream of the flap with the size twice larger than the injection size.The final trade study is to investigate the effect of injection jet momentum coefficient Cµ at 0.05, 0.15, 0.25. The lower Cµ value of 0.05 is the most energy cost effective to increase the lift coefficient. Comparing with the baseline airfoil with the same flap size and deflection angle, at sideslip angle of 0°, the case of Cµ=0.05 of the final configuration achieves a lift coefficient increase by 106.4% from CL=1.09 to 2.25 at very low power coefficient of 0.0285. At the same time, it substantially reduces the drag by 67.17%. All these compound effects result in an increase of aerodynamic efficiency(including CFJ power consumption) by 232.2%. In other words, while the CFJ control surface substantially increases the lift, it simultaneously reduces the net energy cost in a dramatical manner. This even does not count the additional benefit due to the reduced control surface size and weight Finally, CFJ airfoil with no flap is also simulated at injection jet momentum coefficient Cµ=0.05, 0.10, 0.15, 0.20, 0.25 and 0.30. The result shows that the maximum lift coefficients of 3.048 (an increase of 114%) is achieved at Cµ=0.30 with a reduced drag. The aerodynamic efficiency of the flapless control surface is not studied in this work and will be reported in future.The results indicate that flapless control surface may be a feasible option.

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Design of High Wing Loading Compact Electric Airplane Utilizing Co-Flow Jet Flow Control

Cited by 28 publications

References 15 publications

Performance and Energy Expenditure of Coflow Jet Airfoil with Variation of Mach Number

Performance and Energy Expenditure of Coflow Jet Airfoil with Variation of Mach Number

Transonic Airfoil Performance Enhancement Using Co-Flow Jet Active Flow Control

Aircraft Control Surfaces Using Co-flow Jet Active Flow Control Airfoil

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