Research Projects

SCRAMJET engine technology is crucial for various applications, including single and dual-stage-to-orbit reusable launch systems, high-speed air breathing engines, and high-speed weapons delivery systems. When combined with a RAMJET engine, the Dual-Mode-SCRAMJET (DMSJ) can provide thrust to vehicles flying between Mach 3 and Mach 20 with minimal adjustments. However, the SCRAM-RAM transition problem, associated with throttle changes and vehicle acceleration, poses a major hurdle in the advancement of future hypersonic propulsion systems. These transitions can result in increased mechanical and thermal loading, sudden changes in engine thrust, inlet unstart, increased spillage drag, and even catastrophic failure of the entire vehicle. This study proposes experimental and numerical studies on SCRAM-RAM transitions to obtain a deeper physical understanding of the SCRAM-RAM transition dynamics in DMSJ combustors, predict such transitions before they occur, and suppress them using active and passive flow control methods. The study is critical to understanding flow physics in very high-speed air breathing engines and is relevant to the advancement of future high-speed propulsion systems. A dual-mode supersonic combustor with transverse and parallel injection capabilities will be used to simulate a Mach 4.4 flight condition at an altitude of 18.5 km on a total enthalpy basis. Kistler sensors and a linear photodiode array will be used to characterize pressure oscillations in the combustor, and numerical simulations of the transition process will be done using ANSYS-FLUENT.

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