Abstract: An aircraft turbofan engine configuration is described that has two or more high-pressure core modules operating in parallel flowpaths, each comprised of a compressor, a combustor, and a turbine, the axes of which are adjacent to but removed from the engine axis, in lieu of a single high-pressure core serving the same purpose that is coaxial with the engine axis in prior-art designs. An intercooler is included between the low-pressure compressor and the high-pressure compressor that differs from prior-art designs by being made an integral part of the fan stator rather than inserted as a separate entity. Both features offer advantages relative to prior-art designs.

Abstract: An airfoil for use in an axial flow compressor, a high-bypass turbofan or as a turning vane in an airflow duct having a crenelated trailing edge. The crenelated trailing edge produces pairs of counterrotating vortices which promote rapid mixing between the low momentum fluid, in the wake of the airfoil, and the adjacent fluid streams. The mixing of the adjacent streams with the low momentum wake acts to re-energize the wake.

Abstract: An axial flow compressor having a vortex generator system positioned upstream of a rotor with the height of the blades of the vortex generator system being greater then the running clearance of the rotor.The vortex generator system has at least three blades for each of the rotor blades and is spaced from the rotor blades such that the leading edge of the rotor is a distance from the vortex generator system greater then ten times the height of the vortex generator blades and the trailing edge of the rotor blades is a distance from the leading edge of the vortex generator system less then eighty times the height of the vortex generator blades. The spacing between the vortex generator blades is at least four times the height of the vortex generator blades.

Abstract: A reference mark for photo detection is placed on the disc or shaft of a blade carrying rotor of a turbomachine. A first light source and photodetector are aimed at the referencce mark and provide an electrical pulse per revolution. A second light source and photodetector are positioned in the casing of the turbomachine adjacent to the rotor of interest. A first signal from the first photodetector turns on a first and second counter, counting pulses from a high frequency source. A signal from the second photodetector turns off the second counter. The next signal from the first photodetector turns off the first counter. The first counter provides a count of pulses per revolution. The second counter provides a count of pulses representative of arc of movement of the blade tip in interest from the time the reference mark passed the first photodetector until the next blade tip passed the second photodetector.

Abstract: A direct digital measurement proportional to tip clearance of the blades of a turbomachine is obtained by placing at each position on the casing where clearance is to be measured a pair of optical sensors. Each sensor comprises the ends of fiber-optic bundles communicating with a remotely positioned light emitter and a light detector. The sensors in the casing are spaced a short distance apart in the circumferential direction but both located at the same axial coordinate with respect to the axis of rotation. The two sensors each emit a beam of light at an angle to one another measured in a surface of revolution containing both light beams. The light reflected and scattered by a blade passing each beam is transmitted back through the adjacent or concentric fiber optics to photodiode detectors. A signal generator producing a stable frequency of pulses in the megacycle range provides the digital time base.