Tip-to-tail scramjet simulation with plasma-assisted control

A prominent pacing item in the quest for sustained hypersonic flight, and affordable access-to-space capability, is the development of an efficient air-breathing propulsion system. Key barriers of fluid dynamic origin includes, high thermal loads, shock/boundary layer interactions (SBLI) and fuel-air mixing at high-speeds, among other, all of which significantly degrade propulsion efficiency. One approach towards alleviating or eliminating these and other problems, and to provide a crucial energy management function, is to employ electromagnetic fields to control the relatively high temperature, low pressure environment encountered in proposed flight envelopes. To this end, several aspects of magnetogasdynamic (MGD) assisted scramjet flowpaths have been simulated using three-dimensional, integrated, multidisciplinary models requiring the large-scale resources available through the High Performance Computing Modernization Program (HPCMP). In this paper, we describe the complex flow field encountered in a scramjet and its control at various electromagnetic parameters. Among the key conclusions derived from these high-fidelity simulations are the limiting nature of separation and vortical structure formation on MGD generator operation and the deleterious effects of Hall currents, which induce nonintuitive system level asymmetries. Efforts have also focused on obtaining computationally intensive first-principles solutions for various high-temperature effects where phenomenological models have failed. Results from one of these, the modeling of detailed state-to-state kinetics of oxygen and nitrogen mixtures, is described, with emphasis on the derived insight into the phenomenon of vibrational freezing in nozzles, which is a key factor in loss of scramjet propulsion efficiency.