Research On Variable Hypersonic Axisymmetric Inlet

The scramjet inlet, which works in large Mach numbers, should have good performance in thewhole operating range, self-starting and large attack angle. Fixed geometry inlet cannot satisfy theperformance for its fixed structure. Nevertheless variable geometry inlet can improve the performancein all aspects. This paper investigated the performance of the variable hypersonic axisymmetric inlet.In the design of the original axisymmetric inlet, theory of rotational characteristics andTaylor-Maccoll（T-M）equation are applied according to the assigned pressure distribution. Comparedwith the normal triple-cone inlet, the inlet with curved compression surface, performances equally ondesign condition, but has better performance on off-design condition, at large attack angle and lessforces.The performance of three different variable geometry schemes are studied through numericalsimulation. The scheme of translating the whole spike, which changing the distance between thecurved shock and the cowl, the internal compression, improves the performance on off-designcondition. When the spike translates out62mm and16mm, the inlet can restart at Mach3.7and startat8°attack angle. The scheme of channeled spike, which rotating the spike partly and expanding theinternal area, can improve the self-starting performance and work at8°attack angle. The scheme oftranslating the part of the spike, which bleeding the separation region out, can improve theself-starting ability and the performance at large attack angle.