Abstract: A combustion system for a gas turbine engine includes a Catalyst (CAT) combustion sub-system for generating combustion products under a lean premixed fuel/air condition in the presence of a Catalyst and a Dry-Low-Emissions (DLE) combustion sub-system, for generating combustion products under a lean premixed fuel/air condition. Gaseous and liquid fuels are used for the DLE combustion sub-system while only gaseous fuel is used for the CAT combustion system. The engine operates at start-up and under low load conditions with the DLE combustion system and switches over the combustion process to the CAT combustion sub-system under high load conditions. Thus the combustion system according to the invention combines the advantages of DLE and CAT combustion processes so that the gas turbine engine operates over an entire operating range thereof at high engine efficiency while minimizing emissions of nitrogen oxides and carbon monoxide from the engine.

Abstract: A method and apparatus carrying the method for sealing a radial gap between coaxial inner and outer rotating shafts of a gas turbine engine includes using a radial seal as a main seal to seal the gap for a normal engine operation condition, and using an axial seal as a back-up seal for a double seal of the gap. The radial seal provides a seal which meets relatively restrictive leakage requirements for the normal engine operation condition and the axial seal provides a back-up seal which meets less restrictive leakage requirements but is much more tolerant of radial displacement and vibration between the coaxial inner and outer rotating shafts. Thus, an engine operable condition is ensured under abnormal conditions, such as bird strikes, in which the coaxial relationship between the inner and outer rotating shafts are affected by unbalancing forces caused by the bird strike, thereby causing a failure of the radial seal.

Abstract: A combustion system for a gas turbine engine includes a Catalyst (CAT) combustion sub-system for generating combustion products under a lean premixed fuel/air condition in the presence of a Catalyst and a Dry-Low-Emissions (DLE) combustion sub-system, for generating combustion products under a lean premixed fuel/air condition. Gaseous and liquid fuels are used for the DLE combustion sub-system while only gaseous fuel is used for the CAT combustion system. The engine operates at start-up and under low load conditions with the DLE combustion system and switches over the combustion process to the CAT combustion sub-system under high load conditions. Thus the combustion system according to the invention combines the advantages of DLE and CAT combustion processes so that the gas turbine engine operates over an entire operating range thereof at high engine efficiency while minimizing emissions of nitrogen oxides and carbon monoxide from the engine.

Abstract: A ball bearing assembly has an outer ring and an inner ring defining the respective outer and inner races, and a plurality of balls separated on the circumference by a cage ring. The inner ring is split into a loaded half and a non-loaded half. The cage lands on the inner ring halves support the cage ring. An annular groove having a non-rectangular cross-section is disposed at the inner ring bore and at the split face. A plurality of radial grooves extend in the split face of one inner ring half to form radial passages between the annular groove and the inner race for directing oil under centrifugal forces collected in the annular groove, into the inner race. Each radial passage has an aperture in the annular groove located in an intermediate section thereof so that the bottom section of the annular groove acts as a reservoir to feed all the radial passages as well as provide a longer residence time for the oil on loaded inner ring surfaces.