52 ND 3AF INTERNATIONAL CONFERENCE ON APPLIED AERODYNAMICS

Transcription

1 52 ND 3AF INTERNATIONAL CONFERENCE ON APPLIED AERODYNAMICS Numerical sizing of Active Flow Control concepts on the outer wing Lyon, March 28, 2017 Presenter: Jean-Pierre Rosenblum (Dassault Aviation)

2 NUMERICAL SIZING OF ACTIVE FLOW CONTROL CONCEPTS ON THE OUTER WING Jean-Pierre Rosenblum (Dassault Aviation), P. Vrchota (VZLU), S. Wallin, P. Eliasson (FOI), P. Ianelli (CIRA), V. Ciobaca, J. Wild (DLR), J.L. Hantrais-Gervois, M. Costes (ONERA)

3 Recall of Active Flow Control objectives Regions prone to separation In low speed, high lift conditions Global objectives: The aim is to increase the aerodynamic efficiency of the wing at Take-off by delaying potential flow separation in the outer wing region. The use of AFC should help in decreasing the associated drag and increasing L/D, thus leading to a steeper climb gradient in the second segment of climb (when the landing gear is retracted). This presentation is a status of the aerodynamical studies at the end of the first half of the AFLoNext project. Effect of flow separation at wing tip on forces and moments Take-off flight path with one engine inoperative 10 September

4 Take-off configuration Flow condition Name Symbol Value Freestream Mach number M 0.2 Reynolds number unity Re Freestream Temperature T [K] AoA [deg] 2 5 L/D September

5 AFC sizing and Workshare Two identified AFC locations: \ Separation line at the LE \ Wing tip root region Workshare. LE region: Between attachment line & separation line Before wing tip stall At the LE separation line: After wing tip stall On the upper surface: At 10% of chord + SJA Boundary conditions + PJA + SJA + PJA + SJA Volume forcing Boundary conditions Resolved slots Resolved slots Transposition at aircraft level: + SJA + PJA Resolved slots 10 September

6 Lessons from initial CFD with large slots \ Slot width: \ Ranging from 1mm to 4 mm \ 2mm needed at the separation line / 4mm at 10% chord on the upper surface \ Spanwise extension: \ From the wing tip root to nearly the tip end \ Peak velocities: \ Greater than 270 m/s (Mach blowing jet 0.8) \ Pitch angle to the surface: \ For steady blowing: 20 \ For unsteady blowing: 30 \ AFC at the LE separation line with continuous blowing baseline 1.5mm width 2.3mm width 2.3mm 1.5mm lift baseline drag : Mach-jet =1 Pitch angle to surface = 20 AoA=18 Cp 10 September

7 versus Synthetic Jet \ AFC on the upper surface (10% chord) with continuous blowing, Synthetic Jet (sinus or square): 4mm wide slots lift.mjet=0.8 (MF=1.3 kg/s) Synthetic Jet: max Mjet = 0.8 or 0.5 ; 100 Hz Pitch angle to surface = 30 drag Baseline Cfx 10 September

8 Baseline Ct. Blow 273m/s Initial CFD studies with large slots \ AFC on the upper surface (10% chord) with continuous blowing, Synthetic Jet (sinus or square): 4mm wide slots AoA=18 lift drag 10 September

9 Slots taking into account hardware constraints \ Limits due to the hardware technology To get enough peak velocity, do not exceed 5 mm 2 as slot area Typical slot size: 10 mm x 0.5 mm Spacing in span: 1mm Synthetic Jet 3mm Pulsed Jet Spacing between actuator rows: 50mm Synthetic Jet 30 mm Pulsed Jet \ AFC on the upper surface: 10 September

10 Slots taking into account hardware constraints \ AFC at the LE separation line with continuous blowing baseline AoA=18 0.5mm width AoA=18 Cp 0.5mm width AoA=19 lift 0.5mm baseline baseline drag 0.5mm 0.5mm at LE + 3mm at root : M jet = 1 Pitch angle to surface = 20 Cp lift AoA=19 drag 248 PJA at the LE 10 September

11 AFC sizing and Workshare Two identified AFC locations: \ Separation line at the LE \ Wing tip root region Workshare. LE region: Between attachment line & separation line Before wing tip stall At the LE separation line: After wing tip stall On the upper surface: At 10% of chord + SJA Boundary conditions + PJA + SJA + PJA + SJA Volume forcing Boundary conditions Resolved slots Resolved slots Transposition at aircraft level: + SJA + PJA Resolved slots 10 September

12 Conclusions \ The potential of AFC to delay flow separation in the outer wing region has been investigated in the AFLoNext project using CFD. The aim is to improve the L/D at Take-off. \ Several AFC locations have been considered by the partners: \ Either at the leading edge separation line and at the root of the outer wing \ Or on the upper surface (10% of local chord) in order to make integration easier \ First investigations with large slots (from 2mm to 4mm wide) has shown their ability to delay the wing tip stall by at least 2 in AoA. \ Differences in flow mechanisms between steady blowing and Synthetic Jets have been underlined. \ In order to take into account sizing constraints coming from Hardware development within the AFLoNext project, a new set of investigation is being performed. First results show that steady blowing sounds promising. Next investigations will be performed with Synthetic Jets and Pulsed Jets. 10 September

13 This project has received funding from the European Union s Seventh Framework Programme for research, technological development and demonstration under grant agreement No , AFLONEXT project. September