Abstract: The performance of a fixedgeometry twodimensional mixedcompression supersonic inlet with twininlet 90° configuration at the venter of the missile is investigated by wind tunnel tests in this article. Results indicate: ①With the increase of back pressure ratio, the total pressure recovery coefficient at the exit of the inlet increases and the terminal shocks can be stabilized at the convergence area of the inlet. During stablesubcritical operation, the total pressure recovery coefficient is the highest, but the mass flow ratio decreases slightly. ②The total pressure recovery coefficient declines with the increase of the free stream Mach number, while the mass flow ratio ascends gradually and remains at 1.0 when the oblique shock is attached the cowl lip. ③With the increase of the angle of attack, the total pressure recovery coefficient and the mass flow ratio increase. The inlet cannot be started when the angle of attack α rises to 6°at Ma＝2.5 and the angle of yaw β＝0°. ④With the increase of the angle of yaw, the total pressure recovery coefficient and the mass flow ratio decrease, with more decrease at the windward inlet is decrease more than at the leeward inlet. The inlet cannot be started when β=2° at Ma＝2.5 and α＝2°. ⑤The small angle of roll has very slight impact on the performance of the inlet.

Key words: aerospace propulsion system, ramjet engines, twin-inlet 90° configuration at the venter, two-dimensional supersonic inlet, wind tunnel test