Study for Starting Characteristics of Scramjet Engine Test Facility (SETF)

Korea Aerospace Research Institute started on design and development of a hypersonic air-breathing engine test facility from 2000 and completed the test facility installation in July 2009. This facility, designated as the Scramjet engine test facility (SETF), is a blow-down type high enthalpy wind tunnel which has a pressurized air supply system, air heater system, free-jet type test chamber, fuel supply system, facility control/measurement system, and exhaust system with an air ejection. Unlike most aerodynamic wind-tunnel, SETF should simulate the enthalpy condition at a flight condition. To attain a flight condition, a highly stagnated air comes into the test cell through a supersonic nozzle. Also, an air ejector of the SETF is used for simulating altitude conditions of the engine, and facility starting. SETF has a storage air heater (SAH) type heating system. This SAH can supply a hot air with a maximum temperature of 1300K. Using the SAH, SETF can achieve the Mach 5.0 flight at an altitude of 20 km condition. SETF has a free-jet type test cell and this free-jet type test cell can simulate a boundary layer effect between an airplane and engine using the facility nozzle, but it is too difficult to predict the nature of the facility. Therefore it is required to understand the starting characteristics of the facility by experiments. In 2009, a Mach 3.5 test of SETF was done for acceptance testing which is a maximum air supply condition of 20 kg/s. SETF showed the facility efficiency of a 100% without a test model at the Mach 3.5 condition. In 2010, a Mach 6.7 aerodynamic test campaign with a scramjet engine intake. But SETF could not start at the Mach 6.7 condition with the existing ejector system at that time. To get a facility starting, we modified the ejector system. After modification of the ejector system, SETF started at the Mach 6.7 condition with a facility efficiency of 58%. In this paper, the starting characteristics of the SETF with various flight conditions, and modifications of the ejector system will be described.