Scramjets are the technology that will allow for hypersonic cruise to be achieved in the future, allowing for vehicles capable of travelling from London to Tokyo in a couple hours. Additionally, they are a promising technology for reducing the cost of access to space and could allow for single stage to orbit vehicles. However, the internal aerodynamics of a scramjet engine are extremely complicated and not well understood. Scramjet unstart, combustion stability, and off-design operation are several prominant issues severely restricting the functionality and widespread adoption of scramjets as a high speed propulsion technology.
Professor Juliano's group utilizes high spatial resolution techniques such as Background-Oriented Schlieren (BOS), Temperature-Sensitive Paint (TSP), and Pressure-Sensitive Paint (PSP) to investigate axisymmetric and geometrically-complex streamtraced inlets. A key focus is quantifying the behaviour of inlet-generated shockwaves and other flow features in the isolator under steady cold-flow conditions. Injecting air at the aft portion of the isolator allows simulation of combustion-induced choking and inlet unstart. Utilizing high spatial resolution techniques will allow for greater understanding of unstart and methods to predict it, enabling feedback control of scramjet engines in the future.
The Indiana Inlet (INlet). A streamtraced Busemann inlet designed in collaboration with Purdue University and the Air Force Research Lab.
Pressure distribution on the top wall of the Indiana Inlet. Pressure distribution obtained using high speed pressure-sensitive paint sampled at 10 kHz, in collaboration with Professor Hirotaka Sakaue's research group.