Abstract :

A wave-rotor constant-volume pressure-gain combustor is being developed that uses traversing jet ignition. In laboratory testing, it achieved stable combustion at near-atmospheric inlet conditions and demonstrated the potential of pressure-gain combustion using a wave rotor. This technology has the potential for substantial improvements in gas turbine power, efficiency, and emissions. The experiment rig with a motor-driven, room-temperature rotor with large thermal mass operated for short durations within heating limits of extensive in-passage rotating instrumentation. Fast deflagrative combustion was observed with varied fuel distribution in the passages, showing good combustor operability, insensitive to leakage. Remarkably high flame speeds and a net pressure gain were indirectly indicated from measurements. Separate experimental testing of jet ignition in a long aspect ratio constant-volume combustion chamber was achieved with traversing motion of the jet by rotating a prechamber. High-speed Schlieren videography and dynamic pressure transducers showed that ignition delay increases with increasing equivalence ratio, but was relatively insensitive to initial gas temperature in a moderate range. Modeling of transient jet ignition reveals insights into the role of vortex mixing in successful ignition.