Numerical investigation and flow interactions of a mixed-compression hypersonic inlet

Abstract

A numerical investigation of a fixed geometry mixed-compression scramjet inlet is presented in this paper to illustrate the compression process and flow interactions of a hypersonic inlet prior to supersonic combustion. Through the use of an AUSM (Advection Upstream Splitting Method) differencing scheme, applied for both inviscid and turbulent scenarios, this analysis explores the complex phenomena associated with hypersonic flows such as shock-shock and shock-boundary layer interactions. Particular attention is placed in the vicinity of the inlet throat area, where such interactions may cause flow separation and give rise to further complications such as inlet unstart. The inlet geometry is a modified version of the hydrogen-fueled axisymmetric scramjet used on the Hypersonic Flying Laboratory (HFL) named "Kholod", designed and tested by NASA and the Central Institute of Aviation Motors (CIAM) on February 12, 1998. The inlet is computationally solved using the commercial software FLUENT 6.3 and the computational grids were generated using the grid generator GAMBIT 2.4.6. Grid nodes were clustered near the critical flow path areas in order to accurately capture any viscous interactions within the flow field. Solutions presented in this paper assumed free stream properties equivalent to an altitude of 10,000 meters, at 0 degree angle of attack, with Mach numbers of 5, 7, and 9, all solved through both inviscid and turbulent models.