Experimental Study of Effects of Bleed Geometric Parameters on the Performance of a Supersonic Axisymmetric Intake

A supersonic axisymmetric mixed compression air intake has been experimentally studied in a wind tunnel at three free stream Mach numbers of 1.8, 2.0 and 2.2 at zero degrees angle of attack. Shadowgraph flow visualization has been used as well as the pressure transducers. By applying a suction slot over the external compression surface upstream of the throat, the effects of changing the area of the bleed entrance and exit on the intake performance parameters such as mass flow ratio, total pressure recovery, flow distortion and bleed mass flow ratio have been investigated. The results showed that by increasing the area of the bleed entrance, total pressure recovery increases in critical and subcritical conditions and if simultaneously the area of the bleed exit increases, the pressure recovery will be further improved, especially in subcritical condition. The results also indicated that if the area of the bleed entrance becomes very large, it can have an adverse effect on the intake performance, especially in critical condition even worse than the no bleed case. However, using a large bleed entrance can postpone the buzz onset at off-design conditions.