Design And Flow Control Study Of A Variable-Geometry Inlet For ATR

A two-dimensional variable geometry inlet with bleed cavity was designed in this paper,which is matched to air turbo rocket(ATR).With cowl bleed slot,the working range at the over-rated design mach number is expanded.Research on bilateral inlet aerodynamic performance with missile and influence of transition tube on distortion at the engine entrance was conduct with 3D numerical simulations.First,a two-dimensional variable geometry inlet with the flight mach number from 0~3.5 was designed.The results indicate that with higher second ramp angle better inlet performances are obtained at a relatively high free stream mach number.Appropriate increase in the third ramp angle of the inlet make the shock wave intensity more evenly to reduce the loss of total pressure,however which will reduce the inlet of flow coefficient at a relative low free stream mach number.The inlet is able to work at mach number changing from 0 to 3.5.The total pressure recovery coefficient is 0.519 and the flow coefficient is 0.965 at design mach number 3.5.Second,in order to expand the working range at the over-rated design mach number,cowl bleed slot was designed.with numerical simulations,inlet's flowfield characteristics and aerodynamic performances influenced by variable geometry parameters of the cowl bleed slot were studied.The results indicate that with cowl bleed slots the upper limit of inlet working range is increased from Ma3.5 to Ma4.5.With cowl bleed slot of forward sloping,width of 1mm,(?)?1,the flowfield of inlet was improved by the bleed slots,while the influence to aerodynamic performances of cowl bleed slot would be slight.Then,3D numerical simulation study was performed about bilateral inlet with missile The results indicate that.the influence of missile body on total pressure recovery coefficient and flow coefficient increases with the increase of mach number.At the surface behind inlet,total pressure recovery coefficient is 0.942,flow coefficient is 0.949 at design mach number.The inlet's total pressure recovery coefficient is 0.450,and the flow coefficient is 0.913 at design mach number.At positive angle of attack,the performance of the inlet is increased,but separation area appears at high angle of attack,and the performance of the inlet decrease remarkably at negative angle of attack.Flow coefficient and total pressure recovery coefficient at exit of transition tube increases with the increase of side-slip angle.At last,the influence of the transition tube on the total pressure distortion is studied.The results indicate that the total pressure distortion coefficient increases with the increase of length of the transition tube.The combination of the centerline distribution with rapid turning at the entrance and the area distribution with rapid turning at the exit improve the distortion enlarging the inlet exit area reduce the total pressure distortion effectively at Ma1.8.