Flow Separation Control on a NACA 0015 Airfoil using Co-Flow Jet (CFJ) Flow

Abstract

This thesis describes the effort to experimentally verify the high performance characteristics of the co-flow jet (CFJ) airfoil. The CFJ utilizes tangentially injected air at the leading edge and tangentially removed air at the trailing edge to increase lift and stall margin and also decrease drag. The mass flow rates of the injection and suction are equal, so there is a zero net mass flow rate. The existing ME subsonic Aerolab wind tunnel with a one-meter by one-meter test section was modified to accommodate the injection and suction needed for the CFJ airfoils. The compressor and vacuum systems were reconfigured so the mass flow rate of air could be measured and controlled. The sting balance used to hold the airfoil in the test section and gather lift and drag information was also modified from a previous design. One modified airfoil CFJ NACA 0015 and one Basic Airfoil NACA 0015 were tested at KUET. The injection slot and suction slot of Modified airfoil CFJ NACA 0015 had the same slot height which is 0.195 m or 0.65% of chord length. The smaller injection slot size performed superior for increased lift and stall margin, whereas the larger injection slot size performed superior for decreased drag. This type of modified airfoil improved the lift percentage to 82.5% (stall AOA) and a decrease in drag to 16.7% at A0A=25 deg and Cµ= 0.07 when compared to the baseline airfoil. When the mass flow rate was run at high levels, negative drag (i.e., thrust) was measured for both airfoils.