Geared turbofan gas turbine engine architecture

摘要

A gas turbine engine typically includes a fan section, a compressor section, a combustor section and a turbine section. A speed reduction device such as an epicyclical gear assembly may be utilized to drive the fan section such that the fan section may rotate at a speed different than the turbine section so as to increase the overall propulsive efficiency of the engine. In such engine architectures, a shaft driven by one of the turbine sections provides an input to the epicyclical gear assembly that drives the fan section at a speed different than the turbine section such that both the turbine section and the fan section can rotate at closer to optimal speeds providing increased performance attributes and performance by desirable combinations of the disclosed features of the various components of the described and disclosed gas turbine engine.

主权项

1. A gas turbine engine comprising:
a compressor section; a combustor in fluid communication with the compressor section; a turbine section in fluid communication with the combustor, the turbine section including a fan drive turbine and a second turbine, the fan drive turbine including a plurality of turbine rotors; a fan including a plurality of blades rotatable about an axis and a ratio between the number of fan blades and the number of fan drive turbine rotors is between about 2.5 and about 8.5; and a speed change system driven by the fan drive turbine for rotating the fan about the axis, the speed change system comprising a gear box including a sun gear driven by a first shaft of the fan drive turbine at a speed of the fan drive turbine and an output that drives the fan, wherein the fan and the fan drive turbine both rotate in a first direction about the axis; wherein the fan drive turbine includes a first aft rotor attached to the first shaft and the second turbine includes a second aft rotor attached to a second shaft, wherein a first bearing assembly is disposed axially forward of a first connection between the first aft rotor and the first shaft, and a second bearing assembly is disposed axially aft of a second connection between the second aft rotor and the second shaft, and a power density is greater than about 1.5 lbf/in3 and less than or equal to about 5.5 lbf/in3 at sea level take-off thrust, wherein the power density comprises thrust at sea level take-off produced by the engine divided by a volume of the turbine section.