TECHNICAL FIELD

The present disclosure generally relates to gas turbine engines, and more particularly relates to an exhaust system and method for a gas turbine engine.

BACKGROUND

Gas turbine engines may be employed to power various devices. For example, a gas turbine engine may be employed to supply power to a mobile platform, such as an aircraft. In certain examples, the gas turbine engine is an auxiliary power unit, which can supply power to run various electrical systems of the aircraft. Certain electrical systems are supplied by a generator, through a gearbox driven by the gas turbine engine. As needs for power increase, heat output by the generator into a compartment of the gas turbine engine may increase and a temperature of the lubricating fluid associated with the gearbox may also increase. Moreover, in certain instances, the auxiliary power unit can run while the aircraft is on the ground, prior to taxiing for flight. In these instances, noise generated by the auxiliary power unit may be undesirable to one or more passengers or crew onboard the aircraft and service personnel outside.

Accordingly, it is desirable to provide improved exhaust systems and methods for a gas turbine engine, such as an auxiliary power unit, which provides for increased cooling of a compartment of the gas turbine engine, increased cooling of a lubrication fluid, and that attenuates sound generated by the operation of the gas turbine engine. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.

SUMMARY

The various teachings of the present disclosure provide an exhaust system for a gas turbine engine. The exhaust system includes an eductor system adapted to receive a primary exhaust fluid. The eductor system includes a body that extends along a first axis, with a plurality of ducts spaced apart about a circumference of the body. Each of the plurality of ducts extend from the body along a second axis transverse to the first axis to define a plurality of eductor primary flow paths that terminate in a mixing chamber. The mixing chamber is adapted to receive a secondary cooling fluid and to mix the primary exhaust fluid with the secondary cooling fluid to create a mixed fluid flow.

Further provided is a method for attenuating sound generated by a gas turbine engine with an exhaust system. The method includes: receiving a primary exhaust fluid in a primary manifold; receiving a secondary cooling fluid in a secondary plenum; directing the primary exhaust fluid through a plurality of eductor primary flow paths associated with a respective plurality of ducts spaced circumferentially about a primary manifold, the plurality of eductor primary flow paths extending through the secondary plenum; and mixing the primary exhaust fluid and the secondary cooling fluid in a mixing chamber associated with a respective one of the plurality of ducts to create a mixed fluid flow.

Also provided is an exhaust system for a gas turbine engine. The exhaust system includes an eductor system adapted to receive a primary exhaust fluid. The eductor system includes a plurality of ducts spaced apart about a circumference of the eductor system, with each of the plurality of ducts including a plurality of eductor primary flow paths that terminate in a mixing chamber. The mixing chamber is adapted to receive a secondary cooling fluid and to mix the primary exhaust fluid with the secondary cooling fluid to create a mixed fluid flow. The exhaust system includes a muffler system downstream from the mixing chamber adapted to receive the mixed fluid flow from the eductor system. The muffler system includes a plurality of baffles that cooperate to define a tortuous path for the mixed fluid flow and attenuate sound generated by the gas turbine engine.

Further provided is a gas turbine engine. The gas turbine engine includes a combustion section that generates combustive gases that form a primary exhaust flow and an exhaust system downstream from the combustion section. The exhaust system includes an eductor system configured to receive the primary exhaust flow. The eductor system includes a body that extends along a first axis, with a plurality of ducts spaced apart about a circumference of the body, and each of the plurality of ducts define a plurality of eductor primary flow paths that terminate in a mixing chamber. The mixing chamber is adapted to receive a secondary cooling fluid and to mix the primary exhaust fluid with the secondary cooling fluid to create a mixed fluid flow. The exhaust system includes a muffler system downstream from the mixing chamber configured to receive the mixed fluid flow from the eductor system. The muffler system includes a plurality of baffles that cooperate to define a tortuous path for the mixed fluid flow and attenuate sound generated by the gas turbine engine. The exhaust system includes a housing that surrounds the eductor system and the muffler system such that the eductor system and the muffler system are contained within the housing.

Also provided according to various embodiments is an aircraft. The aircraft includes a source of a secondary cooling fluid and a gas turbine engine. The gas turbine engine includes a combustion section that generates combustive gases that form a primary exhaust flow. The aircraft includes an exhaust system downstream from the combustion section. The exhaust system includes an eductor system that receives the primary exhaust flow. The eductor system includes a body that extends along a first axis, with a plurality of ducts spaced apart about a circumference of the body, and each of the plurality of ducts define a plurality of eductor primary flow paths that terminate in a mixing chamber. The mixing chamber is configured to receive the secondary cooling fluid and to mix the primary exhaust fluid with the secondary cooling fluid to create a mixed fluid flow. The exhaust system includes a muffler system downstream from the mixing chamber configured to receive the mixed fluid flow from the eductor system. The muffler system includes a plurality of baffles that cooperate to define a tortuous path for the mixed fluid flow and attenuate sound generated by the gas turbine engine. The exhaust system includes a housing that surrounds the eductor system and the muffler system such that the eductor system and the muffler system are contained within the housing and the housing couples the exhaust system to the gas turbine engine.

