Abstract: An auxiliary power unit (APU) includes a compressor, a turbine, a combustor, and a starter-generator unit all integrated within a single containment housing. The turbine has an output shaft on which the compressor is mounted, and the starter-generator unit is coupled to the turbine output shaft without any intervening gears. The rotating components are all rotationally supported within the containment housing using bearings that do not receive a flow of lubricating fluid.

Abstract: An auxiliary power unit (APU) includes a rotary fuel slinger, and a single-spool, two-stage turbine. The rotary fuel slinger receives a rotational drive force from the turbine, and a supply of fuel from a fuel source. The rotary fuel slinger injects the fuel into a combustor as a continuous “fuel sheet.” As a result, fuel mixing and atomization inside the combustor is improved, which reduces emissions and pattern factor, which in turn increases turbine life.

Abstract: A tortuous path quiet exhaust eductor system may be mounted to a gas turbine engine, such as commercial aircraft APU. The system includes an oil cooler, eductor primary nozzle, oil cooler air nozzle, and surge air dump nozzle. The primary nozzle, oil cooler air nozzle, and surge air dump nozzle direct exhaust flow to entrain APU compartment cooling air, oil cooling air and surge air in a direction having both radial and axial components with respect to the APU centerline axis. The exhaust flow is directed into an eductor mixing duct angled away from the centerline axis and then is turned to enter an exit duct angled toward the centerline axis so that direct line of sight acoustic paths from the tail pipe exit to the turbine exit are blocked, suppressing core noise. The tail pipe ducts may be acoustically treated, further enhancing noise suppression.

Abstract: A tortuous path quiet exhaust eductor system may be mounted to a gas turbine engine, such as commercial aircraft APU. The system includes an oil cooler, eductor primary nozzle, oil cooler air nozzle, and surge air dump nozzle. The primary nozzle, oil cooler air nozzle, and surge air dump nozzle direct exhaust flow to entrain APU compartment cooling air, oil cooling air and surge air in a direction having both radial and axial components with respect to the APU centerline axis. The exhaust flow is directed into an eductor mixing duct angled away from the centerline axis and then is turned to enter an exit duct angled toward the centerline axis so that direct line of sight acoustic paths from the tail pipe exit to the turbine exit are blocked, suppressing core noise. The tail pipe ducts may be acoustically treated, further enhancing noise suppression.

Abstract: A vortex whistle silencing member is secured to the leading and trailing portions of a compressor intake articulated guide vane in such manner that the silencing member is held in a stationary position during pivotal motion of the trailing vane portion between its fully open and closed positions.