Aerojet, under contract to the US Air Force Research Laboratory (AFRL), has completed ground testing of an advanced Scramjet (supersonic combustion ramjet) engine combustor demonstrating a new thermal management approach.
This approach, called core burning, forces the combustion flames away from the Scramjet surfaces thereby reducing overall heat load, the company says in a news release.
The technology overcomes the long-standing challenge of flight speed limiting thermal loads in the combustor. It is expected that the embodiment of core burning will require significantly less fuel to cool the engine and will enable Scramjet engines to have more thermal margin and/or to fly faster than with conventional approaches.
This will be crucial as the Air Force looks to progress from “laboratory” engine scales to those of operational sizes for long-range, time-critical missiles and high-speed military aircraft.
Testing was conducted at Aerojet’s Airbreathing Test Facility in Orange, Virginia. The scramjet test article operated robustly as data were obtained at simulated flight conditions of Mach 3 to Mach 5 and at various simulated altitudes and fuel injection settings.
An Air Force-provided video camera recorded views of the combustion process clearly showing the flame holding and flame propagation processes occurring from the combustor center, thereby proving the core burning concept.
“We are very pleased with the results of the testing,” said Vice President of Defense Programmes, Dick Bregard. “Initial observations clearly indicate the potential for both significant thermal management and engine length improvements.” Further analysis is ongoing to better quantify the improvements, and the results will guide the Air Force and Aerojet in future scramjet propulsion development.