Integrated Analysis of Scramjet Flowpath with Innovative Inlets

Significant progress has been achieved during the first year of this Challenge effort, in developing and simulating configurations which highlight the main scramjet inlet flow path alternatives. In particular, three different types of inward-turning inlets have been explored, including the rectangular cross-section, scoop and "jaws" designs. Each flowpath has been discretized and subjected to inviscid, laminar and turbulent analyses with highly-scalable solvers at design and off-design conditions ranging from Mach 6 to Mach 10. Viscous/inviscid interactions are observed to have a profound impact on the flow, giving rise to distortion of the velocity profile at the exit of the inlet (entrance of the isolator/combustor component). For the jaws approach, the effects of angle-of-attack and yaw have been studied. A complex pattern of low and high total pressure variation is observed, suggesting strategies for the subsequent fuel injection processes. For the rectangular cross-section dual-plane compression inlet, combustor integration has been accomplished with finite-rate chemical kinetics. The effect on mixing characteristics of numerous injection strategies, both upstream and/or in the interior of a wall cavity, are examined. The injection process is observed to yield a separation shock, bow shock and Mach disk, as well as a reattachment shock. Potential phenomena that might generate instabilities and subsequent unstart have been identified, as are locations of high temperature, unburnt fuel gases and combustion efficiency. In a separate, but related effort, simulations have also been performed to yield data for flight-test experiments (HiFIRE program) to ensure survivability of mass capture diagnostic devices.