Patent Application
20180023509
This application relates to a gas turbine engine having a thrust reverser structure wherein at least a portion of the moveable structure is mounted on a fixed fan case.
Gas turbine engines are known and utilized to power aircraft. In a typical gas turbine engine, a fan delivers air into a bypass duct as bypass air and into a core engine as core air. The air in the core engine passes through a compressor where it is compressed and then passed into a combustor. In the combustor, the compressed air is mixed with fuel and ignited. Products of this combustion pass downstream over turbine rotors driving them to rotate.
A gas turbine engine has a number of components that may sometimes require maintenance. Thus, so-called “D-doors” are provided which may be pivoted between an open and a closed position. In the closed position, the D-doors define a portion of the bypass duct, and an inner housing for covering the core engine. When the D-doors are open, a maintenance operator has access to internal features. Forward of the D-doors is a fixed fan case, which surrounds the fan.
A gas turbine engine for aircraft typically has a thrust reverser function. As aircraft lands, its engines have a thrust reverser which is actuated to begin acting against the momentum carrying the aircraft along the runway. In one standard type of thrust reverse, so-called cascades and blocker doors are actuated once the aircraft has landed. The blocker doors block the bypass duct. The cascades are moved to a position such that they push the blocked air in a forward direction resisting the momentum of any movement of the aircraft.
In the prior art, the cascades have been mounted on the D-doors along with actuation structure. This makes the D-doors very heavy and cumbersome to move to an open position.
In a featured embodiment, a gas turbine engine has a core engine and a fan. A pivoting D-door structure includes a pivoting inner D-door portion and an outer D-door portion, which is axially moveable relative to the inner D-door portion between a stowed and thrust reverse position. A fan case surrounds the fan. Cascades are axially moveable along with the outer D-door portion between a stowed and a thrust reverse position. Structure supporting the cascades is mounted on the fan case.
In another embodiment according to the previous embodiment, an actuator is provided on the fan case for driving the cascades and the outer D-door portion between the stowed and thrust reverse positions.
In another embodiment according to any of the previous embodiments, the cascades include a plurality of openings for directing air in a direction opposing further movement of an aircraft receiving the gas turbine engine.
In another embodiment according to any of the previous embodiments, blocker doors are moved to a blocking position when the cascades and the outer D-doors portions are moved to the thrust reverse position.
In another embodiment according to any of the previous embodiments, the actuator for the cascades is a ball screw actuator.
In another embodiment according to any of the previous embodiments, a guide for guiding the cascades is provided with a channel receiving a portion moveable with the cascades.
In another embodiment according to any of the previous embodiments, the actuator for the cascades is a ball screw actuator.
In another embodiment according to any of the previous embodiments, blocker doors are moved to a blocking position when the cascades and the outer D-doors portions are moved to the thrust reverse position.
In another embodiment according to any of the previous embodiments, a guide guiding the cascades is provided with a channel receiving a portion moveable with the cascades.
In another embodiment according to any of the previous embodiments, the cascades include a plurality of openings for directing air in a direction opposing further movement of an aircraft receiving the gas turbine engine.
In another embodiment according to any of the previous embodiments, blocker doors are moved to a blocking position when the cascades and the outer D-doors portions are moved to the thrust reverse position.
In another embodiment according to any of the previous embodiments, an actuator for the cascades is a ball screw actuator.
In another embodiment according to any of the previous embodiments, a guide for guiding the cascades is provided with a channel receiving a portion moveable with the cascades.
In another embodiment according to any of the previous embodiments, a guide for guiding the cascades is provided with a channel receiving a portion moveable with the cascades.
In another embodiment according to any of the previous embodiments, blocker doors are moved to a blocking position when the cascades and the outer D-doors portions are moved to the thrust reverse position.
In another embodiment according to any of the previous embodiments, an actuator for the cascades is a ball screw actuator.
In another embodiment according to any of the previous embodiments, a guide for guiding the cascades is provided with a channel receiving a portion moveable with the cascades.
In another embodiment according to any of the previous embodiments, an actuator for the cascades is a ball screw actuator.
In another embodiment according to any of the previous embodiments, a guide for guiding the cascades is provided with a channel receiving a portion moveable with the cascades.
In another embodiment according to any of the previous embodiments, a guide for guiding the cascades is provided with a channel receiving a portion moveable with the cascades.
These and other features may be best understood from the following drawings and specification.
The exemplary engine 20 generally includes a low speed spool 30 and a high speed spool 32 mounted for rotation about an engine central longitudinal axis A relative to an engine static structure 36 via several bearing systems 38. It should be understood that various bearing systems 38 at various locations may alternatively or additionally be provided, and the location of bearing systems 38 may be varied as appropriate to the application.
The low speed spool 30 generally includes an inner shaft 40 that interconnects a fan 42, a first (or low) pressure compressor 44 and a first (or low) pressure turbine 46. The inner shaft 40 is connected to the fan 42 through a speed change mechanism, which in exemplary gas turbine engine 20 is illustrated as a geared architecture 48 to drive the fan 42 at a lower speed than the low speed spool 30. The high speed spool 32 includes an outer shaft 50 that interconnects a second (or high) pressure compressor 52 and a second (or high) pressure turbine 54. A combustor 56 is arranged in exemplary gas turbine 20 between the high pressure compressor 52 and the high pressure turbine 54. A mid-turbine frame 57 of the engine static structure 36 is arranged generally between the high pressure turbine 54 and the low pressure turbine 46. The mid-turbine frame 57 further supports bearing systems 38 in the turbine section 28. The inner shaft 40 and the outer shaft 50 are concentric and rotate via bearing systems 38 about the engine central longitudinal axis A which is collinear with their longitudinal axes.
The core airflow is compressed by the low pressure compressor 44 then the high pressure compressor 52, mixed and burned with fuel in the combustor 56, then expanded over the high pressure turbine 54 and low pressure turbine 46. The mid-turbine frame 57 includes airfoils 59 which are in the core airflow path C. The turbines 46, 54 rotationally drive the respective low speed spool 30 and high speed spool 32 in response to the expansion. It will be appreciated that each of the positions of the fan section 22, compressor section 24, combustor section 26, turbine section 28, and fan drive gear system 48 may be varied. For example, gear system 48 may be located aft of combustor section 26 or even aft of turbine section 28, and fan section 22 may be positioned forward or aft of the location of gear system 48.
The engine 20 in one example is a high-bypass geared aircraft engine. In a further example, the engine 20 bypass ratio is greater than about six (6), with an example embodiment being greater than about ten (10), the geared architecture 48 is an epicyclic gear train, such as a planetary gear system or other gear system, with a gear reduction ratio of greater than about 2.3 and the low pressure turbine 46 has a pressure ratio that is greater than about five. In one disclosed embodiment, the engine 20 bypass ratio is greater than about ten (10:1), the fan diameter is significantly larger than that of the low pressure compressor 44, and the low pressure turbine 46 has a pressure ratio that is greater than about five 5:1. Low pressure turbine 46 pressure ratio is pressure measured prior to inlet of low pressure turbine 46 as related to the pressure at the outlet of the low pressure turbine 46 prior to an exhaust nozzle. The geared architecture 48 may be an epicycle gear train, such as a planetary gear system or other gear system, with a gear reduction ratio of greater than about 2.3:1. It should be understood, however, that the above parameters are only exemplary of one embodiment of a geared architecture engine and that the present invention is applicable to other gas turbine engines including direct drive turbofans.
A significant amount of thrust is provided by the bypass flow B due to the high bypass ratio. The fan section 22 of the engine 20 is designed for a particular flight condition—typically cruise at about 0.8 Mach and about 35,000 feet (10,668 meters). The flight condition of 0.8 Mach and 35,000 ft (10,668 meters), with the engine at its best fuel consumption—also known as “bucket cruise Thrust Specific Fuel Consumption (‘TSFCT’)”—is the industry standard parameter of lbm of fuel being burned divided by lbf of thrust the engine produces at that minimum point. “Low fan pressure ratio” is the pressure ratio across the fan blade alone, without a Fan Exit Guide Vane (“FEGV”) system. The low fan pressure ratio as disclosed herein according to one non-limiting embodiment is less than about 1.45. “Low corrected fan tip speed” is the actual fan tip speed in ft/sec divided by an industry standard temperature correction of [(Tram° R)/(518.7° R)]0.5. The “Low corrected fan tip speed” as disclosed herein according to one non-limiting embodiment is less than about 1150 ft/second (350.5 meters/second).
In
The blocker door 78 has been pivoted inwardly through some type of mechanism which may be as known in the art. The outer D-door portion 74 and the cascade 76 have been moved rearwardly. The cascade is provided with holes such that air in the bypass duct, which is blocked by the blocker doors 78, will now pass outwardly of the cascade 76 and in a direction resisting further movement of an associated aircraft.
When moved to the deployed position, as shown in
As shown in
Although an embodiment of this invention has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this invention. For that reason, the following claims should be studied to determine the true scope and content of this invention.
