Inlet particle separator for a turbine engine

A method and apparatus for separating particles from an inlet airflow of a turbine engine has a centerbody with a radially outer scavenge conduit. The inlet airflow has entrained particulate matter, which can impact an impact surface defining part of the centerbody. The impact surface can be disposed at an angle or have a low coefficient of restitution to reduce the velocity of the incoming particulate matter. The particulate matter is radially diverted radially outward through the scavenge conduit, unable to make a turn defined by the shape of the centerbody.

BACKGROUND OF THE INVENTION

Engines, and particularly gas or combustion turbine engines, are rotary engines that extract energy from a flow of combusted gases passing through the engine onto a multitude of turbine blades. Gas turbine engines have been used for land and nautical locomotion and power generation, but are most commonly used for aeronautical applications such as for aircraft, including helicopters. In aircraft, gas turbine engines are used for propulsion of the aircraft. In terrestrial applications, turbine engines are often used for power generation. Additionally, fluidic systems where the flow of dirty fluid, such as containing particulate matter, can include a downstream engine, such as in a tank or power plant.

Gas turbine engines for aircraft are designed to operate at high temperatures to maximize engine efficiency, so cooling of certain engine components, such as the high pressure turbine and the low pressure turbine, can be necessary. Typically, cooling is accomplished by ducting cooler air from the high and/or low pressure compressors to the engine components that require cooling. While the turbine air is a high temperature, it is cooler relative to the compressor air, and can be used to cool the turbine. When cooling the turbines, cooling air can be supplied to various turbine components, including the interior of the turbine blades and the turbine shroud.

Particles, such as dirt, dust, sand, volcanic ash, and other environmental contaminants in the engine intake air can cause sever compressor erosion. As the particles move through the engine they can melt in the combustion gases and subsequently resolidify on the turbine flow path surfaces. Particles entrained in the turbine cooling air can cause a loss of cooling due to deposition and plugging of the cooling passages. All of these effects cause reduced operational time or “time-on-wing” for the aircraft environment. This problem is exacerbated in certain operating environments around the globe where turbine engines are exposed to significant amounts of airborne particles.

BRIEF DESCRIPTION OF THE INVENTION

In one aspect, a method of separating particles from an inlet airflow of a turbine engine having a centerbody and defining an engine centerline. The method comprising impacting at least a portion of the inlet airflow against an impact surface, after impacting, turning the airflow about the centerbody, and radially diverting a portion of the airflow relative to the engine centerline during the turning to form a scavenge flow containing inertially bound particles incapable of making the turn.

In another aspect, a gas turbine engine comprising an inlet having a centerbody and defining an inlet duct defining an inlet airflow path, an engine core arranged downstream of the centerbody and defining an engine centerline, and an inlet particle separator having a scavenge plenum arranged radially outwardly about at least a portion of the centerbody and having a plenum inlet fluidly coupling the inlet duct to the scavenge plenum.

In yet another aspect, a gas turbine engine having a centerbody and defining an inlet duct defining an inlet airflow path, an engine core arranged downstream of the centerbody and defining an engine centerline, an inlet particle separator having a scavenge plenum arranged radially outwardly and forming a turn about at least a portion of the centerbody and having a plenum inlet fluidly coupling the inlet duct to the scavenge plenum, and an impact surface formed by at least a portion of the centerbody located upstream of the turn.

DESCRIPTION OF EMBODIMENTS OF THE INVENTION

The described embodiments of the present invention are directed to systems, methods, and other devices related to particle removal, particularly in a turbo shaft turbine engine, and more particularly to the removal of particles from the engine intake airflow to a turbine engine. For purposes of illustration, the present invention will be described with respect to an aircraft gas turbine engine. It will be understood, however, that the invention is not so limited and can have general applicability in non-aircraft applications, such as other mobile applications and non-mobile industrial, commercial, and residential applications.

As used herein, the terms “axial” or “axially” refer to a dimension along a longitudinal axis of an engine or along a longitudinal axis of a component disposed within the engine. The term “forward” used in conjunction with “axial” or “axially” refers to moving in a direction toward the engine inlet, or a component being relatively closer to the engine inlet as compared to another component. The term “aft” used in conjunction with “axial” or “axially” refers to a direction toward the rear or outlet of the engine relative to the engine centerline.

As used herein, the terms “radial” or “radially” refer to a dimension extending between a center longitudinal axis of the engine, an outer engine circumference, or a circular or annular component disposed within the engine. The use of the terms “proximal” or “proximally,” either by themselves or in conjunction with the terms “radial” or “radially,” refers to moving in a direction toward the center longitudinal axis, or a component being relatively closer to the center longitudinal axis as compared to another component.

As used herein, the terms “tangential” or “tangentially” refer to a dimension extending perpendicular to a radial line with respect to the longitudinal axis of the engine or the longitudinal axis of a component disposed therein.

All directional references (e.g., radial, axial, upper, lower, upward, downward, left, right, lateral, front, back, top, bottom, above, below, vertical, horizontal, clockwise, counterclockwise) are only used for identification purposes to aid the reader's understanding of the disclosure, and do not create limitations, particularly as to the position, orientation, or use thereof. Connection references (e.g., attached, coupled, connected, and joined) are to be construed broadly and can include intermediate members between a collection of elements and relative movement between elements unless otherwise indicated. As such, connection references do not necessarily infer that two elements are directly connected and in fixed relation to each other. The exemplary drawings are for purposes of illustration only and the dimensions, positions, order and relative sizes reflected in the drawings attached hereto can vary.

FIG. 1is a schematic cross-sectional diagram of a gas turbine engine10for an aircraft. The engine10has a generally longitudinally extending axis or centerline12extending forward14to aft16. The engine10includes, in downstream serial flow relationship, a compressor section22including a booster or low pressure (LP) compressor24and a high pressure (HP) compressor26, a combustion section28including a combustor30, a turbine section32including a HP turbine34, and a LP turbine36, and an exhaust section38. The HP compressor26, the combustor30, and the HP turbine34form a core44of the engine10, which generates combustion gases. The core casing46surrounds the core44.

A HP shaft or spool48disposed coaxially about the centerline12of the engine10drivingly connects the HP turbine34to the HP compressor26. A LP shaft or spool50, which is disposed coaxially about the centerline12of the engine10within the larger diameter annular HP spool48, drivingly connects the LP turbine36to the LP compressor24. The portions of the engine10mounted to and rotating with either or both of the spools48,50are referred to individually or collectively as a rotor51.

The LP compressor24and the HP compressor26respectively include a plurality of compressor stages52,54, in which a set of compressor blades58rotate relative to a corresponding set of static compressor vanes60,62(also called a nozzle) to compress or pressurize the stream of fluid passing through the stage. In a single compressor stage52,54, multiple compressor blades56,58can be provided in a ring and can extend radially outwardly relative to the centerline12, from a blade platform to a blade tip, while the corresponding static compressor vanes60,62are positioned downstream of and adjacent to the rotating blades56,58. It is noted that the number of blades, vanes, and compressor stages shown inFIG. 1were selected for illustrative purposes only, and that other numbers are possible. The blades56,58for a stage of the compressor can mount to a disk53, which mounts to the corresponding one of the HP and LP spools48,50, with each stage having its own disk. The vanes60,62mount to the core casing46in a circumferential arrangement about the rotor51.

The HP turbine34and the LP turbine36respectively include a plurality of turbine stages64,66, in which a set of turbine blades68,70are rotated relative to a corresponding set of static turbine vanes72,74(also called a nozzle) to extract energy from the stream of fluid passing through the stage. In a single turbine stage64,66, multiple turbine blades68,70can be provided in a ring and can extend radially outwardly relative to the centerline12, from a blade platform to a blade tip, while the corresponding static turbine vanes72,74are positioned upstream of and adjacent to the rotating blades68,70. It is noted that the number of blades, vanes, and turbine stages shown inFIG. 1were selected for illustrative purposes only, and that other numbers are possible.

In operation, air is supplied to the LP compressor24, which then supplies pressurized ambient air to the HP compressor26, which further pressurizes the ambient air. The pressurized air from the HP compressor26is mixed with fuel in the combustor30and ignited, thereby generating combustion gases. Some work is extracted from these gases by the HP turbine34, which drives the HP compressor26. The combustion gases are discharged into the LP turbine36, which extracts additional work to drive the LP compressor24, and the exhaust gas is ultimately discharged from the engine10via the exhaust section38. The driving of the LP turbine36drives the LP spool50to rotate the LP compressor24.

Some of the ambient air can bypass the engine core44and be used for cooling of portions, especially hot portions, of the engine10, and/or used to cool or power other aspects of the aircraft. In the context of a turbine engine, the hot portions of the engine are normally downstream of the combustor30, especially the turbine section32, with the HP turbine34being the hottest portion as it is directly downstream of the combustion section28. Other sources of cooling fluid can be, but is not limited to, fluid discharged from the LP compressor24or the HP compressor26.

Referring toFIG. 2, a cross-section of the gas turbine engine10illustrates an inlet section80and a conduit section82in axial arrangement upstream of the compressor section22, and an outlet section84downstream of the turbine section32. The inlet section80has an inlet particle separator88having an inlet90, a centerbody92, and a scavenge plenum98. The inlet90defines an opening for providing a flow of air to the downstream sections. Axially downstream of the inlet90is the centerbody92having an impact surface94formed by a portion of the centerbody92, confronting a flow of air provided from the inlet90. An inlet duct96is defined about the centerbody92and radially, outwardly bounded by the scavenge plenum98in fluid communication with the inlet duct96. One or more plenum inlets100provide fluid communication between the inlet duct96and the scavenge plenum98. The inlet90, centerbody92, and the scavenge plenum98are all annular, such that the inlet duct96is radially defined around the engine centerline12. It is contemplated that the scavenge plenum98can alternatively comprise other scrolls, scavenge conduits, or can be a combination of multiple scavenge conduits arranged radially about the engine centerline12.

The conduit section82has a flow conduit102fluidly coupling the inlet duct96to the compressor section22of the engine10. The flow of air provided to the inlet90can pass around the centerbody92through the inlet duct96and to the flow conduit102, providing air to the compressor section22. The outlet section84has one or more struts104arranged radially around the engine centerline12.

Turning toFIG. 3, an exploded view of the inlet particle separator88, best illustrating the combination of the components for providing an airflow to the engine core44. A front plate120mounts to a scavenge conduit122, defining the scavenge plenum98. The front plate120and centerbody92for the radially outward flowing inlet to the turn96. Particles are accelerated in a radially outward direction for scavenging through the plenum inlets100. The scavenge conduit122has a scavenge outlet124for providing a scavenge flow of air overboard. Radially within the scavenge conduit122is the centerbody92. A scavenge inlet section126can comprise a plurality of annular scavenge vanes128mounted to one or more bands130to define the plenum inlets100ofFIG. 2. The scavenge vanes128comprise wedge-shaped bodies oriented to define a radial disposition of the plenum inlets100is radial. Alternatively, it is contemplated that the scavenge vanes128can be any shape, such that the wedge-shape is non-limiting. Furthermore, the disposition of the scavenge vanes128can define an axial orientation for the plenum inlets100. While four scavenge vanes128are shown, any number of scavenge vanes128is contemplated to define any number of plenum inlets100. An inner member132and an outer member134can define the radially inner and outer bounds of the flow conduit102axially downstream of the centerbody92. The centerbody92and the inner member can couple in axial arrangement, being supported within the outer arrangement of the scavenge conduit122and the scavenge inlet section126.

The structural elements of the inlet particle separator88are easily interconnectable to form the inlet particle separator88. The inlet particle separator88can be mechanically removable from the conduit section82. Installation and maintenance of the inlet section80is facilitated with easy of removability. It should be understood, however, that differing manufacturing combinations are possible to develop the apparatus disclosed herein.

FIG. 4illustrates a cross-section of the inlet duct96of the inlet particle separator88, best illustrating radially outer136and inner138surfaces defining the inlet90, the inlet duct96, and the flow conduit102to define a flow path140. The inlet duct96further defines a turn142about the centerbody92, having the impact surface94upstream of the inlet duct96. The plenum inlets100fluidly couple to the inlet duct96at the turn142. The inlet duct96can further have an inlet144and an outlet146. The inlet144can have a minimum cross-sectional area to accelerate the air entering the inlet duct96. Additionally, the outlet146can have a minimum cross-sectional area downstream of the plenum inlets100, such that an airflow entering the flow conduit102decelerates before moving to the compressor section22. The turn142can be defined between the inlet144and the outlet146and can comprise a turn angle148of at least 120 degrees, while a turn having any angle is contemplated. The turn142can couple to the plenum inlets100at an apex of the turn142. The plenum inlets100as shown can be disposed in a manner complementary to the flow within the turn142. For example, if the centerbody92defines a particular angle for the turn142relative to the engine centerline12, the plenum inlet100at that portion of the turn142can be angled relative to or complementary to the turn142to prevent negative impact to the engine performance. Furthermore, more or less plenum inlets100can be utilized based upon the particular engine10or inlet90design.

An inlet flow150is provided through the inlet90, having a substantially axial flow direction. The inlet flow150turns to move into the inlet duct96in a substantially radially outward direction and accelerates into the turn142. Particular matter entrained within the inlet flow150can turn into the inlet duct96, or will have a great enough mass, that it will impact the impact surface94before moving into the inlet duct96, reducing the inertia of the particulate matter. A duct airflow152will pass through the turn142, having a portion of the air move into the flow conduit102, with the other portion of the duct airflow152passing through the plenum inlets100as a scavenge flow154. Particulate matter entrained within the duct airflow152will have a velocity to define an inertia that will carry a percentage of the particulate matter through the plenum inlets100with the scavenge flow154, removing a percentage of the particulate matter from a cleaner airflow156being provided to the compressor section22through the flow conduit102. It should be appreciated that utilizing a substantial turn142in combination with an impact surface94and radially disposed scavenge conduit122can remove a remove a greater portion of particulate matter entering the engine10, as compared to other inlet particle separators having a smaller turn142.

Turning now toFIGS. 5A and 5B, a flow of particulate matter is illustrated impacting the impact surface94. Looking atFIG. 5A, a stream of particulate matter160will move in a substantially axial flow path with a flow of air provided to the engine10. The impact surface94at a contact point161of the particulate matter160can be disposed at an angle. A radial axis162can extend through the contact point161orthogonal to the engine centerline12. An impact axis164can be defined along the impact surface94through the contact point161. A first forward angle166exists between the radial axis162and the impact axis164and a second forward angle168exists between the impact axis164and the axial flow streamline of the particulate matter160. The centerbody92can be shaped such that the impact surface94defines the first and second forward angles166,168being 90-degrees or less.

As can be appreciated, the particulate matter160will contact the impact surface94and can scatter in a plurality of directions before travelling into the inlet duct96and entering the turn142, before having a large portion of the particulate matter160pass through the plenum inlets100. The angles166,168defined by the impact surface94can vary to direct the trajectory of the particulate matter or to develop a region of aerodynamic stagnation to slow the particulate matter. The geometry of the impact surface provides an opportunity to rebound the particles into the oncoming inlet airflow150and slow the velocity of the particulate matter. Once the particle velocity is considerably reduced, aerodynamic drag will re-accelerate the particle and strongly influence the particle trajectory. After impact, the particle will be reaccelerated largely in a radial direction as It enters inlet144and continues in a radially outward direction to the scavenge plenum inlets100.

Looking atFIG. 5B, the impact surface94can have a low coefficient of restitution (CoR), such that the particulate matter160impacting the centerbody92will impact in an inelastic collision, acting in a less chaotic manner, while decreasing velocity and inertia of the particulate matter. The combination of the angled surface and the low CoR for the surface can result in particles having a significant decrease in velocity relative to their inlet speeds. The low CoR can provide a more direct path for the particulate matter toward the plenum inlets100, such that less plenum inlets100are required or system efficiency can be increased.

FIG. 6is a flow chart illustrating a method200of separating particles from an inlet flow of a turbine engine10. The turbine engine can define a centerbody and have a centerbody. At202, a flow of air is provided to the gas turbine engine10through an inlet90. As204, at least a portion of the airflow impacts against an impact surface94on the centerbody92. Impacting the airflow can comprise impacting the airflow against the impact surface94at a forward angle being 90 degrees or less relative to either the engine centerline12or the airflow streamline, or both, such that the impact surface94forms an acute forward angle. Additionally, the impact surface can have a low CoR, reducing the inertia of the particular matter after impact. The reduced inertia can determine a more directed flow path for the particulate matter after impact. The CoR can result in an inelastic collision of the particles at the impact surface.

After impacting, at206, the airflow can turn about the centerbody92. The airflow turns about the centerbody92. The turn can be greater than 120 degrees, while a turn of any angle is contemplated. The airflow can pass through a minimum cross-sectional area to accelerate the airflow during the turn. At208, a portion of the airflow is radially diverted, relative to the engine centerline12, during the turning of the airflow to form a scavenge flow containing inertially bound particles incapable of making the turn. The radially diverted scavenge flow can be diverted at the apex of the turn. A scavenge conduit122can have a scavenge plenum98for accepting the particle laden scavenge flow and moving the scavenge airflow to another portion of the engine10or overboard.

The impacted particles results in the particles scattering in a chaotic manner. Utilizing an impact surface94having a low CoR as well as an angled surface reduces the particle velocity, having the particle velocity then dominated by drag and can then direct the particulate matter toward the plenum inlets100. The direction of the particulate matter can increase the efficiency of the system in removing particles from the airflow moving into the engine10. Furthermore, direction of the particulate matter can reduce the number of required scavenge vanes128, reducing size and weight, while simplifying the inlet particle separator88.

It should be appreciated that the inlet particle separator as described comprising a radially outward entrance for the particle separation and scavenge flow in combination with a substantial flow turn efficiently separates both large and fine particulate matter from the airflow entering the engine. Additionally a forward impact surface with a low coefficient of restitution and an angled surface can decrease particulate matter velocity to increase the amount of particulate matter separated from the airflow.

Moving the scavenge conduit to a radially outbound position also allows for optimum mounting location for the gearbox.