Flowfield Structure in Generic Inward-Turning-Based Propulsion Flowpath Components

The flowfields encountered in generic scramjet components is described, with emphasis on inlet and combustor segments. In the former category, results are presented on two design approaches, including the so-called “jaws” and contoured “sugar-scoop” frameworks. A comparison is also made with previous analyses on a traditional rectangular cross-section inlet design comprised of planar surfaces. The features of the flowfield encountered in these configurations are shown to be strongly dependent on the shock structure and viscous-inviscid interactions. The main parameters, including particularly flowfield distortion and the correlation with shock/boundary layer interactions are obtained with inviscid, laminar and two-equation-based turbulent analyses. In the second part of the paper, the coupling of each of these inlet designs to a common generic downstream combustor is described. The focus is on the immediate vicinity of a hydrocarbon-based configuration utilizing a cavity-based flameholder of circular cross-section. The general propulsion analysis chemical kinetics and two phase procedure (GPACT) is employed with a 13-specie, 20 reaction ethylene chemistry model directly coupled to a two-equation turbulence model. The effect of a specific configuration comprised of a sequence of circumferentially distributed injectors on the backward facing cavity step is explored.