Abstract
This paper presents a 3D flapped co-flow jet (FCFJ) airfoil with a quasi-micro-compressor to study the performance at different operating conditions within the flight envelope from low speed takeoff/landing to cruise. The FCFJ airfoil has a flap of 60%C with CFJ implemented on the flap as part of the airfoil. CFJ injection and suction ducts are designed for the cruise condition of Mach 0.25 with a flap deflection angle (ss) of 10 degrees, which corresponds to an angle of attack (AoA) of 7 degrees. The FCFJ airfoil has an injection and suction duct that has a circular interface with the micro-compressor and transitions to a rectangle slot at the airfoil. Design iteration of the ducts is an important step in the integration of CFJ airfoil and micro-compressor by matching the mass flow rate and compressor total pressure ratio. The micro-compressor is represented by compressor boundary conditions provided by the compressor design and is therefore a quasi-micro-compressor. The purpose is to understand how the aerodynamic performance of the FCFJ varies as the airfoil flap deflection angle (ss) is changed from an initial position of 70 degrees at takeoff to 10 degrees at cruise. The takeoff condition is at low speed with a freestream Mach of 0.07 for ss = 60 degrees and 70 degrees. As ss is decreased from takeoff toward the cruise condition, the freestream Mach number is increased to Mach 0.17 for ss = 30 degrees, 40 degrees, and 50 degrees, and then to Mach 0.25 for ss = 0 degrees, 5 degrees, 10 degrees, 15 degrees, and 20 degrees. Results show both the lift coefficient (CL) and the drag coefficient (CD) decreasing as ss varies from takeoff to cruise. A high CL of 6.9 occurs at takeoff ss = 70 degrees with an AoA of 50 degrees. The lowest CFJ power coefficient (Pc) occurs at the cruise condition of Mach 0.25 and ss = 10 degrees, which is selected as the cruise condition with an AoA of 7 degrees, lift coefficient CL of 1.77, CL/CD of 89.8, (CL/CD) c of 44.6, and C2L/CDc of 79.2. The highest corrected aerodynamic efficiency (CL/CDc) is 45.5 at cruise Mach 0.25 and ss = 15 degrees. This study demonstrates that it is feasible to use the FCFJ airfoil for the entire flight envelope for short takeoff/landing with high lift coefficient and cruise with high aerodynamic efficiency and productivity efficiency.