A new pulse facility for studies on rocket based combined cycles

The new high-enthalpy pulse facility developed at CNR-IENI-Milano for basic studies on combined cycles propulsion systems is described. The facility is based on a 100 liters volume free-piston compressor. The test chamber, embodied into a large dump tank, is wide enough to contain small scale models of motors and all necessary diagnostic systems. Mach number profiles, pressure and temperature of the test section air flow have been obtained in the Mach number range 3 - 7. The test gas is clean air for Mach numbers lower than 4.5 and vitiated air for higher speeds, as hydrogen pre-combustion is used to enhance the flow enthalpy. Dynamic pressure data fall in the flight corridor generally accepted for air-breathing propulsion. The results of a preliminary experimental investigation on a miniaturized hydrogen/oxygen rocket motor are given. On this ground, a small size rocket-based air-breathing prototype was designed, built and instrumented with pressure and temperature probes. A number of preliminary tests at simulated flight Mach numbers in the range 3.5 - 6.5 successfully demonstrated the actual capabilities of the experimental facility, the correct synchronization of air flow and rocket motor operation, and the global performance of the data acquisition system.