Patent Description:
A typical geared turbofan engine includes a fan section, a compressor section, a combustor section and a turbine section. A rotor of the fan section is connected to and driven by a rotor of the turbine section through a shaft and a gear train. During engine operation, lubrication oil is provided to the gear train to lubricate and cool components of the gear train. The gear train may subsequently direct this lubrication oil to a gutter that circumscribes the gear train.

Various gutter configurations are known in the art, some of which may have relatively low oil capture efficiencies. Such a gutter therefore may collect a relatively small amount of the lubrication oil that is initially directed to the gutter by the gear train. The uncollected lubrication oil may churn in a space defined radially between the gutter and the gear train. The churning lubrication oil may re-contact the gear train, which may reduce power transfer efficiency of the gear train between the turbine rotor and the fan rotor. A low oil capture efficiency may also reduce the amount of lubrication oil available to an auxiliary lubrication system, which provides the lubrication oil to the gear train during negative g maneuvers.

There is a need in the art for a gutter with an improved fluid capture efficiency.

<CIT> and <CIT> disclose arrangements of the prior art.

According to an aspect of the invention, a turbine engine system is provided by claim <NUM>.

At least a portion of the channel located adjacent and upstream of the channel outlet has the channel geometry.

The width of the inner region may be greater than the width of the outer region.

The channel regions may include an intermediate region located radially between the inner region and the outer region. The geometry of the intermediate region may be substantially trapezoidal.

The channel geometry may be a first channel geometry. The first channel geometry may transition to a second (e.g., different) channel geometry as the channel extends circumferentially within the gutter.

The channel outlet may have a substantially triangular cross-sectional geometry. Alternatively, the channel outlet may have a substantially rectangular cross-sectional geometry, or any other shaped cross-sectional geometry.

The gutter may include a conduit that extends through the gutter and/or spirals at least partially around the centerline between the channel outlet and a conduit outlet.

The gear train may include one or more fluid passages arranged circumferentially around the centerline and aligned axially with the channel. The one or more fluid passages may be fluidly coupled to the channel outlet through the channel.

The gear train may be configured as a planetary gear train or a star gear train, or any other type of epicyclic gear train.

The system may include a plurality of turbine engine rotors arranged along the axial centerline and including a first rotor and a second rotor. Each of the engine rotors may include a plurality of rotor blades arranged around and connected to a rotor disk. The first rotor may be connected to and driven by the second rotor through the gear train.

The first rotor may be configured as a fan rotor. The second rotor may be configured as a turbine rotor. The first and/or the second rotors may alternatively be configured as any other type of turbine engine rotor.

<FIG> illustrates a turbine engine system <NUM> that includes a gear train <NUM> (e.g., an epicyclic gear train), a rotational input element <NUM> and a rotational output element <NUM>. The gear train <NUM> has an axial centerline <NUM>, and is connected to and transmits mechanical power between the input element <NUM> and the output element <NUM>. The input element <NUM> is a turbine engine shaft, and the output element <NUM> is a turbine engine rotor (e.g., a fan rotor).

Referring to <FIG> and <FIG>, the gear train <NUM> includes a plurality of gears <NUM>, 31a-e and <NUM> arranged in a star gear train configuration. Alternatively, the gears may be arranged in a planetary gear train configuration, or any other type of gear train configuration. For example, <FIG> is a schematic illustration of another gear train <NUM>' that includes a plurality of gears <NUM>', 31a-b' and <NUM>' arranged in a planetary gear train configuration. Referring again to <FIG> and <FIG>, the gears include a sun gear <NUM>, one or more star gears 31a-e, and a ring gear <NUM>.

The sun gear <NUM> is rotatable about the centerline <NUM>, and is connected to the input shaft <NUM> through a joint such as a spline joint. The star gears 31a-e are arranged circumferentially around the centerline <NUM>. The star gears 31a-e are radially meshed between the sun gear <NUM> and the ring gear <NUM>. Each of the star gears 31a-e is rotatable about a respective axis 34a-e.

Each of the star gears 31a-e is rotatably connected to a stationary gear carrier <NUM> through a respective bearing 38a-e. Each bearing 38a-e may be a journal bearing as illustrated in <FIG> and <FIG>, or alternatively any other type of bearing such as a roller element bearing, etc. The gear carrier <NUM> is connected to a turbine engine case through a support strut and/or a flexible support.

The ring gear <NUM> is rotatable about the centerline <NUM>, and is connected to the output element <NUM> through a joint such as a bolted flange joint. Alternatively, the ring gear may be connected to the input element and the sun gear may be connected to the output element.

The turbine engine system <NUM> also includes a fluid collection gutter <NUM> that at least partially circumscribes the gear train <NUM>. The gutter <NUM> of <FIG>, for example, is configured as an annular body that extends circumferentially around the centerline <NUM>. The gutter <NUM> includes a gutter inner surface <NUM>, a fluid collection channel <NUM> and a fluid return conduit <NUM>. The inner surface <NUM> at least partially defines a bore <NUM> (e.g., an axial gutter bore) in which the gear train <NUM> is arranged.

Referring to <FIG>, the bore <NUM> has an inner surface <NUM> that is defined by a substantially circular cross-sectional geometry. The inner surface <NUM> has a bore area defined by a surface radius <NUM>. Alternatively, the bore <NUM> may have various other non-circular (e.g., arcuate or polygonal) cross-sectional geometries that define the bore area.

Referring to <FIG>, the channel <NUM> is defined by one or more surfaces of the gutter <NUM>, which may include a channel end surface <NUM> and opposing channel side surfaces <NUM> and <NUM>. That is, geometrically, the channel <NUM> extends radially outward into the gutter <NUM> from the inner surface <NUM> to the end surface <NUM>. Axially, the channel <NUM> extends within the gutter <NUM> between the side surfaces <NUM> and <NUM>. Circumferentially, the channel <NUM> extends through the gutter <NUM> to a channel outlet <NUM>, which is also an inlet (e.g., scoop) for the conduit <NUM>.

The channel <NUM> has a substantially rectangular cross-sectional geometry with a cross-sectional channel area. Various other cross-sectional geometries may define the channel, as described below.

Referring to <FIG>, at least a portion of the area of the channel <NUM>, located proximate (e.g., adjacent) and upstream of the channel outlet <NUM>, is substantially equal to or less than between about two percent of the bore area. The channel height <NUM>, in the engine radial direction, extends from the gutter inner surface <NUM> to the gutter end surface <NUM>, and is substantially equal to or less than between about eight percent of the surface radius <NUM>. The channel width <NUM>, in the engine axial direction, extends between the gutter side surfaces <NUM> and <NUM>, and is substantially equal to or less than between about five and about fifteen percent of the surface radius <NUM>. These dimensional relationships may increase a fluid capture efficiency of the gutter <NUM> as described below.

Referring to <FIG>, the channel outlet <NUM> has a substantially rectangular cross-sectional geometry. Alternatively, the channel outlet may have various other cross-sectional geometries that define the outlet area as described below. Referring to <FIG>, the rectangular cross-sectional geometry defines a cross-sectional outlet area that is substantially equal to between about fifty-five and about seventy-five percent of the channel area. This dimensional relationship may further increase the fluid capture efficiency of the gutter <NUM> as described below.

The conduit <NUM> is defined by one or more interior surfaces of the gutter <NUM>, which may include opposing conduit end surfaces 64a-b and opposing conduit side surfaces 66a-b. In the engine radial direction, the conduit <NUM> extends within the gutter <NUM> between the end surfaces 64a-b. In the engine axial direction, the conduit <NUM> extends within the gutter <NUM> between the side surfaces 66a-b. The conduit <NUM> extends through the gutter <NUM> and may at least partially spiral around the centerline <NUM> from the channel outlet <NUM> to a conduit outlet <NUM> (see <FIG>).

Referring to <FIG>, <FIG>, <FIG>, the gutter <NUM> is connected to a stationary support <NUM> such as a support strut that connects a bearing <NUM> to the turbine engine case. The gear train <NUM> is arranged and mated with the gutter <NUM>. The channel <NUM> is aligned in the engine axial direction with one or more fluid passages <NUM> included in the gear train <NUM>. These fluid passages <NUM> are arranged circumferentially around the centerline <NUM>, and extend in the engine radial direction through the ring gear <NUM>. The channel <NUM> is arranged in the engine axial direction between a pair of annular seals <NUM> (e.g., knife edge seals), which engage (e.g., contact) the gutter inner surface <NUM> in the engine radial direction. In this manner, the fluid passages <NUM> are fluidly coupled to the channel <NUM> and thus to the conduit <NUM> through the channel <NUM>.

During system <NUM> operation, an inlet manifold <NUM> provides lubrication and/or heat exchange fluid (e.g., lubrication oil) to the gear train <NUM>. The fluid may lubricate meshing surfaces of the sun, star and ring gears <NUM>, 31a-e and <NUM> and/or engaging surfaces of the star gears 31a-e and the bearings 38a-e. The fluid may also or alternatively remove heat energy from the sun, star and ring gears <NUM>-<NUM> and/or the bearings 38a-e.

The fluid is collected from the gear train <NUM> with the gutter <NUM>. Centrifugal force induced by rotation of the ring gear <NUM>, for example, may cause at least a portion of the fluid within the gear train <NUM> to flow through the fluid passages <NUM> and radially into the channel <NUM>. The channel outlet <NUM> directs (e.g., scoops) the fluid from the channel <NUM> into the conduit <NUM>. The conduit <NUM> directs the fluid to the conduit outlet <NUM>, which may be fluidly coupled to a fluid reservoir (e.g., an auxiliary oil reservoir for the gear train <NUM>) or to any other lubrication system component. The fluid may subsequently be cooled and/or filtered, and re-circulated through the gear train <NUM> for further gear train component lubrication and/or cooling.

Under certain conditions, gas (e.g., air) within a plenum <NUM> surrounding the gear train <NUM> may flow with the fluid through the fluid passages <NUM> into the channel <NUM>. The gas may also or alternatively leak into the channel <NUM> from between the gutter <NUM> and one or more of the seals <NUM>. The ratio of gas to fluid within the channel <NUM> may affect the capture efficiency of the gutter <NUM>. The term "capture efficiency" may describe the ratio of an amount of fluid output by the channel outlet <NUM> to an amount of fluid that initially flows into the channel <NUM> from the gear train <NUM>.

Where the ratio of gas to fluid within a gutter channel is relatively large, the gas may reduce the velocity of the fluid in the engine circumferential direction. Such a reduction in circumferential velocity may cause the fluid to swirl within the channel increasing leakage at the end surface and thus the channel outlet; e.g., churn within the channel. The churning fluid may subsequently re-contact the ring gear, which may reduce power transfer efficiency of the gear train between the inlet and the outlet elements. The disclosed gutter <NUM>, however, may reduce the ratio of gas to fluid within the channel <NUM> and thus increase the capture efficiency of the gutter <NUM> where the channel area is sized substantially equal to or less than about two percent of the bore area as set forth above. Such a configuration, for example, balances the channel area to fluid velocity relationship. Where the channel is relatively large, for example, the fluid velocity slows and may be unable to pressurize the auxiliary tanks. Where the channel is relatively small, the side leakage increases causing low capture efficiency.

The ratio of the outlet area to the channel area may also affect the capture efficiency of the gutter <NUM>. For example, where the ratio of the outlet area to the channel area is relatively large, a relatively large channel outlet may receive (e.g., scoop) a relatively large amount of the gas from the channel along with the fluid. This received gas may choke or otherwise obstruct the flow of the fluid through the conduit, which may reduce the amount of the fluid the gutter collects and thus the capture efficiency of the gutter. Alternatively, where the ratio of the outlet area to the channel area is relatively small, a relatively small size of the channel outlet may restrict the amount of fluid that is received from the channel and thus reduce the capture efficiency of the gutter. The disclosed gutter <NUM>, however, may reduce air choking within the conduit <NUM> without restricting the amount of gas received from the channel <NUM> where the outlet area is substantially equal to between about fifty-five and about seventy-five percent of the channel area as set forth above.

<FIG> illustrates the gutter <NUM> with an alternative channel <NUM>. In contrast to the channel <NUM> of <FIG>, at least a portion of the channel <NUM> has a cross-sectional tapered channel geometry (e.g., a multi-region channel geometry) that defines the channel area. Referring to <FIG>, as the channel <NUM> extends around the centerline <NUM>, the tapered channel geometry transitions into a different (e.g., substantially rectangular) cross-sectional channel geometry. Alternatively, the entire channel <NUM> may have the tapered channel geometry.

Referring again to <FIG>, the tapered channel geometry axially tapers as the channel <NUM> extends radially into the gutter <NUM> towards a channel end <NUM>. The tapered channel geometry is formed by an inner region <NUM> and an outer region <NUM>, each having a unique (e.g., different) geometry. The inner region <NUM> extends radially into the gutter <NUM> from the inner surface <NUM>, and has a substantially rectangular geometry. The outer region <NUM> is located radially outboard of the inner region <NUM>. The outer region <NUM> extends radially into the gutter <NUM> from the inner region <NUM> to the channel end <NUM>, and has a substantially triangular geometry. Referring to <FIG>, the channel outlet <NUM>' has a corresponding substantially triangular cross-sectional geometry that defines the outlet area.

Referring to <FIG> and <FIG>, the tapered channel geometry may increase the capture efficiency of the gutter <NUM> by directing the received fluid radially outward towards the channel end <NUM>. Canted surfaces <NUM> that define the outer region <NUM>, for example, may funnel the fluid towards the channel end <NUM>, and reduce swirl within the channel. The fluid may therefore collect into a mass at (e.g., proximate, adjacent or on) the channel end <NUM> as the fluid flows through the channel <NUM> towards the channel outlet <NUM>'. Such a fluid mass may also be less affected by swirling gas within the channel <NUM> than dispersed fluid droplets. In contrast, as illustrated in <FIG>, swirling gas within a channel <NUM> with a rectangular cross-sectional geometry may cause some of the fluid to swirl out of the channel <NUM> and thus away from the channel outlet. The rectangular cross-sectional geometry therefore may decrease the capture efficiency of the gutter <NUM>.

<FIG> illustrates the gutter <NUM> with channel <NUM> in accordance with embodiments of the invention. In contrast to the channel <NUM> of <FIG>, the tapered channel geometry is formed by an inner region <NUM> and an outer region <NUM>, each having a unique (e.g., different) width in the engine axial direction. Each also has a substantially uniform geometry.

The inner region <NUM> extends in the engine radial direction into the gutter <NUM> from the inner surface <NUM>. The inner region <NUM> has a substantially rectangular geometry with a first width <NUM>. The outer region <NUM> is located outboard in the engine radial direction of the inner region <NUM>. The outer region <NUM> extends in the engine radial direction into the gutter <NUM> from the inner region <NUM> to the channel end <NUM>. The outer region <NUM> has a substantially rectangular geometry with a second width <NUM> that is less than the first width <NUM>.

Referring to <FIG>, the channel outlet <NUM>" has a corresponding substantially rectangular cross-sectional geometry. This geometry defines the outlet area.

<FIG> illustrates the gutter <NUM> with an alternative channel <NUM> in accordance with embodiments of the invention. In contrast to the channel <NUM> of <FIG>, the tapered channel geometry is formed by an inner region <NUM>, an intermediate region <NUM> and an outer region <NUM>, each having a unique geometry and/or a unique width in the engine axial direction. The inner region <NUM> extends into the gutter <NUM> in the engine radial direction from the inner surface <NUM>. The inner region <NUM> has a substantially rectangular geometry with a first width <NUM>. The intermediate region <NUM> is located outboard in the engine radial direction of the inner region <NUM>. The region <NUM> extends into the gutter <NUM> in the engine radial direction from the inner region <NUM>.

The intermediate region <NUM> has a substantially trapezoidal geometry. The outer region <NUM> is located outboard of the inner in the engine radial direction and the intermediate regions <NUM> and <NUM>. The region <NUM> extends into the gutter <NUM> in the engine radial direction from the intermediate region <NUM> to the channel end <NUM>.

The outer region <NUM> has a substantially rectangular geometry with a second width <NUM> that is less than the first width <NUM>. Referring to <FIG>, the channel outlet <NUM>‴ has a tapered (e.g., multi-region) cross-sectional geometry that corresponds to the geometries of the intermediate and the outer regions <NUM> and <NUM>.

The gutter <NUM> may have various configurations other than those described above and illustrated in the drawings. For example, the gutter <NUM> may have a tapered cross-sectional geometry where the channel area is greater than about two percent of the bore area. In addition or alternatively, the gutter <NUM> may have a channel height that is greater than about eight percent of the surface radius, and/or a channel width that is greater than about fifteen percent of the surface radius. In addition or alternatively, the gutter <NUM> may have an outlet area that is less than about fifty-five percent of the channel area, or that is greater than about seventy-five percent of the channel area. The tapered cross-sectional geometry may have a single channel region with a substantially triangular or trapezoidal geometry, or any other type of axially tapered geometry. The gutter <NUM> may include a fluid baffle <NUM> (e.g., an apertured oil baffle) as illustrated in <FIG>, or may be configured without a baffle as illustrated in <FIG>. The gutter <NUM> may be configured as a stator as described above, or alternatively configured to rotate about the centerline <NUM>; e.g., with the ring gear <NUM>. The present invention therefore is not limited to any particular gutter configurations.

<FIG> is a side cutaway illustration of a geared turbine engine <NUM> which may include the turbine engine system <NUM> of <FIG>. The turbine engine <NUM> is a two-spool turbofan that generally incorporates a fan section <NUM>, a compressor section <NUM>, a combustor section <NUM> and a turbine section <NUM>. The fan section <NUM> drives air along a bypass flowpath while the compressor section <NUM> drives air along a core flowpath for compression and communication into the combustor section <NUM> then expansion through the turbine section <NUM>. Although depicted as a turbofan gas turbine engine in the disclosed non-limiting embodiment, it should be understood that the concepts described herein are not limited to use with turbofans as the teachings may be applied to other types of turbine engines such as a three-spool (plus fan) engine wherein an intermediate spool includes an intermediate pressure compressor (IPC) between the LPC and HPC and an intermediate pressure turbine (IPT) between the HPT and LPT.

The engine <NUM> generally includes a low spool <NUM> and a high spool <NUM> mounted for rotation about an engine central longitudinal axis A relative to an engine static structure <NUM> via several bearing structures <NUM>. The low spool <NUM> generally includes an inner shaft <NUM> that interconnects a fan <NUM>, a low pressure compressor <NUM> ("LPC") and a low pressure turbine <NUM> ("LPT"). The inner shaft <NUM> drives a fan rotor <NUM> of the fan <NUM> directly or through a geared architecture <NUM> to drive the fan <NUM> at a lower speed than the low spool <NUM>. An exemplary reduction transmission is an epicyclic transmission, namely a planetary or star gear system.

The high spool <NUM> includes an outer shaft <NUM> that interconnects a high pressure compressor <NUM> ("HPC") and high pressure turbine <NUM> ("HPT"). A combustor <NUM> is arranged between the high pressure compressor <NUM> and the high pressure turbine <NUM>. The inner shaft <NUM> and the outer shaft <NUM> are concentric and rotate about the engine central longitudinal axis A (e.g., the centerline <NUM>) which is collinear with their longitudinal axes.

Core airflow is compressed by the low pressure compressor <NUM> then the high pressure compressor <NUM>, mixed with the fuel and burned in the combustor <NUM>, then expanded over the high pressure turbine <NUM> and low pressure turbine <NUM>. The turbines <NUM>, <NUM> rotationally drive the respective low spool <NUM> and high spool <NUM> in response to the expansion.

The main engine shafts <NUM>, <NUM> are supported at a plurality of points by bearing structures <NUM> within the static structure <NUM>. It should be understood that various bearing structures <NUM> at various locations may alternatively or additionally be provided.

In one non-limiting example, the gas turbine engine <NUM> is a high-bypass geared aircraft engine. In a further example, the gas turbine engine <NUM> bypass ratio is greater than about six (<NUM>:<NUM>). The geared architecture <NUM> can include an epicyclic gear train (e.g., the gear train <NUM>), such as a planetary gear system or other gear system. An example epicyclic gear train has a gear reduction ratio of greater than about <NUM>:<NUM>, and in another example is greater than about <NUM>:<NUM>. The geared turbofan enables operation of the low spool <NUM> at higher speeds which can increase the operational efficiency of the low pressure compressor <NUM> and low pressure turbine <NUM> and render increased pressure in a fewer number of stages.

A pressure ratio associated with the low pressure turbine <NUM> is pressure measured prior to the inlet of the low pressure turbine <NUM> as related to the pressure at the outlet of the low pressure turbine <NUM> prior to an exhaust nozzle of the gas turbine engine <NUM>. In one non-limiting embodiment, the bypass ratio of the gas turbine engine <NUM> is greater than about ten (<NUM>:<NUM>), the fan diameter is significantly larger than that of the low pressure compressor <NUM>, and the low pressure turbine <NUM> has a pressure ratio that is greater than about <NUM> (<NUM>:<NUM>). It should be understood, however, that the above parameters are only exemplary of one embodiment of a geared architecture engine and that the present disclosure is applicable to other gas turbine engines including direct drive turbofans.

In one embodiment, a significant amount of thrust is provided by the bypass flow path B due to the high bypass ratio. The fan section <NUM> of the gas turbine engine <NUM> is designed for a particular flight condition - typically cruise at about <NUM> Mach and about <NUM>,<NUM> feet (<NUM>). This flight condition, with the gas turbine engine <NUM> at its best fuel consumption, is also known as bucket cruise Thrust Specific Fuel Consumption (TSFC). TSFC is an industry standard parameter of fuel consumption per unit of thrust.

Fan Pressure Ratio is the pressure ratio across a blade of the fan section <NUM> without the use of a Fan Exit Guide Vane system. The low Fan Pressure Ratio according to one non-limiting embodiment of the example gas turbine engine <NUM> is less than <NUM>. Low Corrected Fan Tip Speed is the actual fan tip speed divided by an industry standard temperature correction of "T" / <NUM><NUM> in which "T" represents the ambient temperature in degrees Rankine. The Low Corrected Fan Tip Speed according to one non-limiting embodiment of the example gas turbine engine <NUM> is less than about <NUM> fps (<NUM>/s).

A person of skill in the art will recognize the turbine engine system <NUM> of <FIG> may be included in various turbine engines other than the one described above. The turbine engine system <NUM>, for example, may be included in a geared turbine engine where a gear train connects one or more shafts to one or more rotors in a fan section and/or a compressor section. Alternatively, the turbine engine system <NUM> may be included in a turbine engine configured without a gear train. The present invention therefore is not limited to any particular types or configurations of turbine engines.

The terms "upstream", "downstream", "inner" and "outer" are used to orient the components of the turbine engine system <NUM> described above relative to the turbine engine and its axis. A person of skill in the art will recognize, however, one or more of these components may be utilized in other orientations than those described above. The present invention therefore is not limited to any particular spatial orientations.

While various embodiments of the present invention have been disclosed, it will be apparent to those of ordinary skill in the art that many more embodiments and implementations are possible within the scope of the invention which is defined by the appended claims.

Claim 1:
A system for a gas turbine engine, comprising:
a gear train (<NUM>) with an axial centerline (<NUM>); and
a gutter (<NUM>) disposed radially outside of the axial centerline (<NUM>), the gutter at least partially circumscribing the gear train (<NUM>), and including:
an inner surface (<NUM>); and
a channel (<NUM>, <NUM>, <NUM>) configured to receive fluid directed out of the gear train (<NUM>), the channel (<NUM>, <NUM>, <NUM>) extending radially into the gutter (<NUM>) from the inner surface (<NUM>) to a channel end (<NUM>), and circumferentially to a channel outlet (<NUM>);
at least a portion of the channel (<NUM>, <NUM>, <NUM>) has a cross-sectional channel geometry that tapers axially as the channel (<NUM>, <NUM>, <NUM>) extends radially towards the channel end (<NUM>);
the cross-sectional channel geometry including an inner region (<NUM>, <NUM>) and an outer region (<NUM>, <NUM>);
the inner region (<NUM>, <NUM>) having a substantially rectangular geometry; and
the outer region (<NUM>, <NUM>) having a substantially rectangular geometry.