The Investigation On A Hypersonic Sidewall-compression Scramjet Inlet With Varied Geometry

Scramjet inlet with fixed geometry cannot satisfy the design point and off-design pointperformance and the start at low Mach number due to the wide Mach number working range of thehypersonic vehicle. Scramjet inlet with varied geometry improves the start performance while keepsthe required quality at the design point. The influence of the sidewall compression angle, thecompression distribution between side compression and ramp compression, inlet aspect ratio, cowlangle and compensatory angle are investigated on the fixed geometry sidewall-compression inletwithin Mach number4to7. A comprehensive model with translating cowl, variable throat andtopwall and rotating cowl is simulated to compare the start performance of the three variablegeometry programs. A regulation law of fixed geometry sidewall-compression inlet within Machnumber4to7is presented. As a result, the three variable geometry programs fulfill both low Machnumber start and design point performance. When the angle of attack is0and8degree, the inlet canself-start.Based on2D rotational flow theory and given wall pressure rise law, a curved topwall isdesigned under the same size and compression to increase total pressure recovery coefficient and flowcoefficient of the sidewall-compression inlet. On this basis, the design of triangle cowl and improvedisentropic compression sidewall further improves the comprehensive property of the inlet. Thesimulation of the new curved sidewall-compression inlet proves the feasibility of the variablegeometry program.