Publication Date

2019-02-09

Availability

Open access

Embargo Period

2019-02-08

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Mechanical Engineering (Engineering)

Date of Defense

2018-07-06

First Committee Member

Ge-Cheng Zha

Second Committee Member

Weiyong Gu

Third Committee Member

Xiangyang Zhou

Abstract

The objective of this thesis is to investigate The objective of this thesis is to investigate the double surface Co-Flow Jet (CFJ) on the transonic supercritical RAE2822 airfoil. Configurations are explored to improved CFJ airfoil performance, such as aerodynamic efficiency CL and lift coefficient (L/D)C. All the configurations are simulated and verified using the in-house CFD code, FASIP. The Reynolds Averaged Navier-Stokes (RANS) equations with one-equation Spalart-Allmaras (SA) turbulence model is used. A 5th order weighted essentially nonoscillatory (WENO) scheme with a low diffusion Riemann solver is utilized to evaluate the inviscid utilized. A 2nd order central differencing scheme matching the stencil width of the WENO scheme is employed for the viscous terms. It is shown that CFJ can significantly enhance the aerodynamic performance of RAE2822 transonic supercritical airfoil. The standard CFJ airfoil has an injection slot near the leading edge and a suction slot near the trailing edge on the airfoil suction surface. A small amount of mass ow is sucked into the airfoil near the trailing edge, energized by a micro-compressor located inside the airfoil, and in the tangential direction near the leading edge. For the double surface CFJ airfoil proposed in this paper, an additional injection slot is placed on the pressure surface of the airfoil, and the suction slot remains on the airfoil upper surface. By adding additional injection to the traditional CFJ, lift coefficient CL is further improved, while aerodynamic efficiency (L/D)C is mostly kept same as the standard CFJ airfoil achieved. The jet along the lower surface of the airfoil reduces the local velocity which increase the pressure and lift. The baseline RAE2822 airfoil and the standard CFJ RAE2822 airfoil at a different angle of attacks (AoA) were simulated and compared for the reference. For the freestream condition of Minf = 0.729, Reinf = 6.5*106 and AoA from 1 degree to 5.5 degree, the new CFJ RAE2822 airfoil is able to increase CL by 5.489 % and (L/D)C by 0.83% at peak (L/D)C point compared to the standard airfoil. Different momentum coefficient is also studied. A low total Cmu of 0.002 will increase the CL from 0.7133 to 0.7524, and increase of 5.489%,a high total Cmu of 0.004 will increase the CL from 1.016 to 1.136, and an increase of 11.76%. The double surface airfoil provides a different approach to enhance the performance of transonic airfoils.

Keywords

Co-Flow Jet; CFJ; RAE2822; Transonic Airfoil; Circulation Control; CFD

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