Performance of a scramjet engine model in Mach 6 flight condition

The supersonic combustion ramjet (scramjet) is expected to be the most effective propulsion system for space transportation and hypersonic transportation of the next generation. Japan Aerospace Exploration Agency, Kakuda Space Propulsion Center (JAXA-KSPC) has been conducting firing tests of a variety of sub-scale scramjet engine models in Mach 4, 6, 8 simulated flight conditions using Ramjet Engine Test Facility (RJTF). [1] At each flight condition, the engines produced thrust greater than the engine drag. However, under relatively low Mach number conditions such as Mach 4 and 6, the obtained thrusts in these tests were insufficient because unstart transition occurred at fuel equivalence ratios less than unity. A modified sidewall-compression-type scramjet engine (E2) was fabricated to improve engine performance. It was designed to reduce distortions caused by the swept angle in the frame and the airflow. For this purpose, the E2 model has no swept angle on the sidewalls except in its inlet section.