Simulation of 3D Co-Flow Jet Airfoil with Integrated Micro-Compressor Actuator at Different Cruise Mach Numbers

Abstract

This paper presents a 3D Co-Flow Jet (CFJ) active flow control airfoil with an integrated micro-compressor at different flight conditions that make the micro-compressor actuator work at different operating conditions. The simulations are performed at Mach 0.25, 0.3, and 0.4 with the angle of attack varying around the cruise condition. The RPM of the embedded micro-compressor is controlled to achieve a variety of operating conditions to satisfy the different flight conditions. The micro-compressor actuator is designed for high efficiency at a required mass flow rate in order for the CFJ airfoil to maintain a desired momentum coefficient (Cµ). For each Mach number, different operating points are studied by fixing the compressor RPM at different values and varying the angle of attack (AoA) of the CFJ airfoil. The aerodynamic performance, CFJ mass flow rate, energy expenditure, and 3D flow field are studied for each case. Results show the micro-compressor mass flow rate linearly increases with the CFJ airfoil AoA until the airfoil stalls. The CFJ airfoil will stall before the micro-compressor chokes. Airfoil stall decreases the mass flow rate going through the compressor, preventing the compressor from obtaining a higher mass flow. The aerodynamic performance of the CFJ airfoil shows a maximum CL/CD of 625.9 and a maximum corrected aerodynamic efficiency (CL/CD)c of 66.7 for the case of M = 0.25 at compressor RPM 27,000 and AoA = 0° where the micro-compressor efficiency (η) is 76.6%. As a comparison with the baseline airfoil at cruise AoA of 5°, the integrated CFJ airfoil achieves an increase of CL, CL/CD, (CL/CD)c, and (C2L/CD)c by 26%, 89%, 1.2%, and 27% respectively. This indicates that the CFJ airfoil can indeed be used for efficiency cruise with high cruise lift coefficient. For large AoAs leading to airfoil stall, the micro-compressor RPM needs to be increased to shift the micro-compressor operating line towards a higher mass flow rate and Cµ. This study is a virtual simulation of the integrated system of the CFJ airfoil and the micro-compressor actuator to examine the aerodynamic performance and show how the CFJ airfoil can be controlled within a flight envelope at different operating conditions.