Patent Description:
Aircraft engines, such as gas turbine engines, use compressed air from the compressor section for cooling components of the turbine section. This compressed air may be channelled within cavities defined by stator vanes of the turbine section. In some cases, this air may flow in an undesired manner. Improvements are therefore sought.

<CIT> <CIT> and <CIT> disclose prior art stators of turbine sections.

In one aspect of the invention, there is provided a stator of a turbine section, comprising: vanes circumferentially distributed around a central axis, a vane of the vanes extending along a spanwise axis from a first end to a second end, the vane defining an internal passage extending from the first end to the second end; an insert received within the internal passage of the vane, the insert defining a cavity for receiving cooling air, the insert defining impingement cooling apertures in fluid communication with the cavity and facing an inner face of the vane; a splitter plate secured within the cavity of the insert between the first end and the second end and being transverse to the spanwise axis, the splitter plate having a base secured to the insert and a tip protruding from the base; and a flow passage defined between the tip of the splitter plate and the insert, the flow passage fluidly connecting a first section of the cavity located on a first side of the splitter plate to a second section of the cavity located on a second side of the splitter plate, the tip of the splitter plate secured to the insert at at least one location along a perimeter of the tip.

The stator described above may include any of the following features, in any combinations.

In some embodiments, the tip extends from a proximal end at the base to a distal end, the distal end secured to the insert.

In some embodiments, the insert includes a rear end proximate a trailing edge of the vane and a fore end, the at least one location corresponding to the fore end.

In some embodiments, the flow passage includes two flow passages.

In some embodiments, the two flow passages are located on opposite sides of the tip.

In some embodiments, the splitter plate is free of a cantilevered section.

In some embodiments, a perimeter of the base is secured to the insert via a braze joint.

In some embodiments, the insert includes a rear end proximate a trailing edge of the vane and a fore end, the insert defining a slit extending from the rear end toward a front end of the insert, the splitter plate received within the slit.

In some embodiments, the insert includes a portion free of the slit, the portion extending from the front end towards the rear end, the flow passage defined between the portion of the insert and the tip of the insert.

In some embodiments, a braze joint is at the at least one location where the tip is secured to the insert.

In another aspect of the invention, there is provided a turbine section as set forth in claim <NUM>.

<FIG> illustrates a gas turbine engine <NUM> of a type preferably provided for use in subsonic flight, generally comprising in serial flow communication an inlet <NUM> receiving ambient air, a compressor section <NUM> for pressurizing the air, a combustor <NUM> in which the compressed air is mixed with fuel and ignited for generating an annular stream of hot combustion gases, a turbine section <NUM> for extracting energy from the combustion gases and for driving the compressor section <NUM> and for driving an output shaft <NUM> via a gearbox <NUM>, and an outlet <NUM> for outputting combustion gases. The compressor section <NUM> and the turbine section <NUM> are rotatable about a central axis A of the gas turbine engine <NUM>.

In the embodiment shown, the gas turbine engine <NUM> comprises a high-pressure spool having a high-pressure shaft <NUM> drivingly engaging a high-pressure turbine 14A of the turbine section <NUM> to a high-pressure compressor 12A of the compressor section <NUM>, and a low-pressure spool having a low-pressure shaft <NUM> drivingly engaging a low-pressure turbine 14B of the turbine section <NUM> to a low-pressure compressor 12B of the compressor section <NUM> and drivingly engaged to the output shaft <NUM>, herein via the gearbox <NUM>. It will be understood that the contents of the present disclosure may be applicable to any suitable engines, such as turbofans, turboshafts, auxiliary power units, and hybrid aircraft engines without departing from the scope of the present disclosure.

The term "spool" is herein intended to broadly refer to drivingly-connected turbine and compressor rotors and is, thus, not limited to a compressor and turbine assembly on a single shaft. It also includes a rotary assembly with multiple shafts geared together.

Referring to <FIG>, the turbine section <NUM> includes a stator <NUM> upstream of a rotor of the high-pressure turbine 14A relative to a flow direction F1 within a core gaspath <NUM> of the gas turbine engine <NUM>. This stator <NUM> includes a plurality of stator vanes, referred to simply as vanes <NUM> below, circumferentially distributed about the central axis A for orienting the flow of combustion gases before it meets blades of the rotor of the high-pressure turbine 14A. The stator <NUM> may be located immediately downstream of the combustor <NUM>. The principles of the present disclosure may apply to any stator of the turbine section <NUM>.

The vanes <NUM> are hollow and internally cooled using cooling air, such as air from the compressor section <NUM>. More specifically, a plenum <NUM> surrounds the combustor <NUM>. This plenum <NUM> may be annular and is in fluid communication with an outlet of the high-pressure compressor 12A. The high-pressure compressor 12A may be an impeller having an outlet in fluid communication with diffuser pipes <NUM>. These diffuser pipes <NUM> may deliver the flow of compressed air in the plenum <NUM>. A portion of this flow of compressed air may flow around the combustor <NUM> along a cooling flow direction F2. This portion may thus flow through inner passages defined by the vanes <NUM>.

Referring to <FIG>, a portion of the stator <NUM> is shown. In the embodiment shown, the stator <NUM> includes a plurality of vane segments <NUM> circumferentially distributed around the central axis A. The stator <NUM> is therefore a segmented ring. In some embodiments, the turbine stator may be a full ring. One of the vane segments <NUM> is shown in <FIG> and includes some of the vanes <NUM>, herein two, but each vane segments <NUM> may include more or less than two vanes <NUM>. The vane segments <NUM> includes a radially outer wall <NUM> and a radially inner wall <NUM>. The vanes <NUM> extend from the radially outer wall <NUM> to the radially inner wall <NUM>. Each of the vane segments <NUM> may be a monolithic body defining the radially outer wall <NUM>, the radially inner wall <NUM>, and some (e.g. <NUM>) of the vanes <NUM>. Other configurations are contemplated as well.

Referring to <FIG>, the vanes <NUM> are described in greater detail. The singular form is used below for simplicity, but the below description may apply to each of the vanes <NUM>. The vane <NUM> has a radially outer end 31A secured to the outer wall <NUM> and a radially inner end 31B secured to the inner wall <NUM>. The vane <NUM> has a leading edge 31C and a trailing edge 31D downstream of the leading edge 31C relative to a flow in the core gaspath <NUM>. The vane <NUM> is hollow and includes a front internal passage 31E and a rear internal passage 31F separated from the front internal passage 31E by a rib <NUM> that extends within the vane <NUM> from the outer end 31A to the inner end 31B. The front internal passage 31E and the rear internal passage 31F may extend from the radially outer end 31A to the radially inner end 31B of the vane <NUM>.

A front insert <NUM> is received within the front internal passage 31E and a rear insert <NUM> is received within the rear internal passage 31F. The front and rear inserts <NUM>, <NUM> are hollow to receive the cooling air and define impingement cooling apertures <NUM> extending through walls of the inserts <NUM>, <NUM>. In other words, the front and rear inserts <NUM>, <NUM> define cavities for receiving the cooling air. The impingement cooling apertures <NUM> are designed to output the flow of cooling air from internal passages of the front and rear inserts <NUM>, <NUM> and to direct this flow of cooling air in the form of impingement jets against the inner faces 31I (i.e. the wall surfaces bounding the hollow interior of the vanes) of the vanes <NUM>. In other words, the impingement cooling apertures <NUM> face the inner faces 31I of the vanes <NUM>. By doing so, heat that is transferred from the combustion gases to outer faces 31O of the vanes <NUM>, and by conduction from the outer faces 31O to the inner faces 31I, may be at least partially transferred by convection to the air that exits the impingement cooling apertures <NUM> of the inserts <NUM>, <NUM> and that impinges the inner faces 31I of the vanes <NUM>.

Posts or spacers <NUM> may be disposed between the inner faces 31I and the inserts <NUM>, <NUM> to maintain adequate spacing between the inner faces <NUM> of the vanes <NUM> and the inserts <NUM>, <NUM> to allow the air to exit the internal passages of the inserts <NUM>, <NUM> and to impinge on the vanes <NUM>. These spacers <NUM> may be secured to the vanes <NUM> and/or to the inserts <NUM>, <NUM>.

Referring to <FIG>, the outer wall <NUM> defines front outer apertures 33A for receiving the compressed air. These front outer apertures 33A are in registry and communicate with the front internal passages 31E of the vanes <NUM>. The outer wall <NUM> further defines rear outer apertures 33B that are in registry and communicate with the rear internal passages 31F of the vanes <NUM>. As shown in <FIG>, the inner wall <NUM> defines rear inner apertures 34A for receiving the compressed air. These rear inner apertures 34A are in registry and communicate with the rear internal passages 31F of the vanes <NUM>. In the embodiment shown, the inner wall <NUM> does not define front inner aperture. Thus, cooling air may be supplied to the front internal passage 31E of the vane <NUM> solely via the radially outer end 31A of the vane <NUM>. In some other embodiments, the inner wall <NUM> may define front inner apertures.

As illustrated in <FIG> and <FIG>, cooling air is flown through the vanes <NUM> via both the radially outer and inner ends 31A, 31B of the vanes <NUM> via the rear outer and inner apertures 33B, 34A. As shown in <FIG>, cooling air is flown inside the front and rear inserts <NUM>, <NUM> via their radially-outer ends along flow direction F3 and flown inside the rear insert <NUM> via its radially-inner end along flow direction F4. This cooling air then flows through the impingement cooling apertures <NUM> defined by the rear inserts <NUM> received within the vanes <NUM>. After exiting these impingement cooling apertures <NUM> along flow direction F5, the cooling air impinges on the inner faces <NUM> of the vanes <NUM> for impingement cooling. However, since the rear internal passages 31F of the vanes <NUM> are fed with cooling air via both of the outer ends 31A and inner ends 31B, care should be taken to ensure that this cooling air exits the rear inserts <NUM> via the impingement cooling apertures <NUM> rather than simply flow through the vanes <NUM>. In some cases, the cooling air may experience more resistance by flowing through the impingement cooling apertures <NUM> compared than flowing across the vanes <NUM>.

Referring now to <FIG>, an example of one of the rear inserts <NUM> is illustrated and described below using the singular form. The below description may apply to all of the rear inserts <NUM>. In the embodiment shown, the rear insert <NUM> defines a slit <NUM> that is sized to accept a splitter plate <NUM>. The splitter plate <NUM> is secured within the cavity of the rear insert <NUM> between the radially outer end 31A and the radially inner end 31B of the vane <NUM> and is transverse to a spanwise axis of the vane <NUM>. The splitter plate <NUM> may be located at a mid-span location of the rear insert <NUM>, or at any other suitable spanwise location. The splitter plate <NUM> may be made of sheet metal. This splitter plate <NUM> is used to prevent the cooling air from flowing through the vane <NUM> and bypassing the impingement cooling apertures <NUM>. With the splitter plate <NUM>, a major portion the air (e.g., <NUM>% or more) is forced to flow through the impingement cooling apertures <NUM> along the flow direction F5 (<FIG>). The rear insert <NUM> and the splitter plate <NUM> may be cast, MIM, or 3D printed as a single monolithic part.

In the present embodiment, the slit <NUM> is used to allow the insertion of the splitter plate <NUM> within the rear insert <NUM>. More specifically, in some embodiments, it may not be possible to insert the splitter plate <NUM> via the inner or outer ends of the rear insert <NUM> because of a varying cross-sectional area or shape of the rear insert <NUM>. To insert the splitter plate <NUM> inside the rear insert <NUM>, the slit <NUM> may be manufactured (e.g., machined). This slit <NUM> may extend from the rear end 41C of the rear insert <NUM> towards the fore end 41D. This slit <NUM> may not extend all the way to the fore end 41D. Thus, the rear insert <NUM> may include a portion free of the slit <NUM>. This may avoid splitting the rear insert <NUM> in two parts. The splitter plate <NUM> may be inserted inside the rear insert <NUM> by being inserted inside this slit <NUM>. The splitter plate <NUM> may thus be received within the slit <NUM>. It will be appreciated that, in some other embodiments, the splitter plate <NUM> may be inserted within the rear insert <NUM> via one of the ends of the rear insert <NUM>.

<FIG> represents a top cross-sectional view of the rear insert <NUM> taken along a plane normal to a spanwise axis of the vane <NUM> to illustrate the splitter plate <NUM> and to show how the splitter plate <NUM> is secured to the rear insert <NUM>. As shown in <FIG>, the rear insert <NUM> has a substantially triangular cross-section. Consequently, a width of the rear insert <NUM> increases from a rear end 41C to a fore end 41D. To be able to insert the splitter plate <NUM> inside the slit <NUM>, a width of the tip 43B is less than a width of the rear insert <NUM> at the fore end 41D. More specifically, the width of the tip 43B is less than the width of the rear insert <NUM> at a location corresponding to where the slit <NUM> ends. This may ensure that there is no interference between the tip 43B of the splitter plate <NUM> and the rear insert <NUM> during the insertion of the splitter plate <NUM> within the slit <NUM>. Other configurations are contemplated. In some embodiments, it may be possible to insert the splitter plate via one of the two ends 31A, 31B of the vane <NUM>.

In the embodiment shown, the splitter plate <NUM> has a base 43A and a tip 43B protruding from the base 43A. A dashed line is shown in <FIG> to illustrate an intersection between the base 43A and the tip 43B. The base 43A is secured to the rear insert <NUM>. In the present embodiment, the base 43A abuts against the insert <NUM>. A perimeter 43P of the base 43A may be secured to the rear insert <NUM> via a braze joint <NUM>. An entirety of the perimeter 43P of the base 43A may be secured to the rear insert <NUM>. Alternatively, the base 43A may be secured at a plurality of discrete locations around the perimeter 43P of the base 43A. The tip 43B may start where a width of the splitter plate <NUM> defines a sudden decrease.

Referring to <FIG>, the splitter plate <NUM> is used to limit the cooling air from flowing from one of the ends of the vane <NUM> to the other. However, should one of the outer end 31A or the inner end 31B of the vane <NUM> become clogged, it may be desirable to maintain appropriate cooling air through the impingement cooling apertures <NUM>. Consequently, at least one flow passage <NUM> (<FIG>), two in the embodiment shown, are defined to fluidly connect inner and outer sections 41A, 41B of the cavity of the rear inserts <NUM>. In the present embodiment, these flow passages <NUM> are defined between the tip 43B of the splitter plate <NUM> and the rear insert <NUM>. These flow passages <NUM> may be a by-product of a shape of the splitter plate <NUM> required for its insertion within the insert <NUM> via the slit <NUM> as explained herein above. The flow passages <NUM> may be defined between the portion of the rear insert <NUM> that is free of the slit <NUM> and the tip 43B of the splitter plate <NUM>. In the embodiment shown, the flow passages <NUM> include two flow passages <NUM> for each of the splitter plates <NUM>. The two flow passages <NUM> may be located on opposite sides of the tip 43B. The flow passage(s) <NUM> fluidly connects the outer section 41A of the cavity of the insert <NUM>, which is located on a first side of the splitter plate <NUM>, to the inner section 41B of the cavity of the insert <NUM>, which located on a second side of the splitter plate <NUM>.

Therefore, air may flow past the splitter plate <NUM> via these flow passages <NUM>. Therefore, if the outer end 31A of the vane <NUM> becomes clogged, cooling air may reach the impingement cooling apertures <NUM> defined within the outer section 41A of the rear insert <NUM> via the flow passages <NUM>. Similarly, if the inner end 31B of the vane <NUM> becomes clogged, cooling air may reach the impingement cooling aperture <NUM> of the inner section 41B of the rear insert <NUM> via the flow passages <NUM>. The outer section 41A of the rear insert <NUM> defines an outer cavity of the rear insert <NUM>. The outer section 41A is in fluid flow communication with an outer group of the impingement cooling apertures <NUM>. Similarly, the inner section 41B of the rear insert <NUM> define an inner cavity of the rear insert <NUM>. The inner section 41B is in fluid flow communication with an inner group of the impingement cooling apertures <NUM>. The flow passage(s) <NUM> may provide adequate fluid communication between the outer and inner cavities of the rear insert <NUM>. Thus, should the inner end of the vane <NUM> or rear insert <NUM> become clogged or partially clogged, the inner group of the impingement cooling apertures <NUM> may receive cooling air from the outer section 41A of the rear insert <NUM> via the flow passage(s) <NUM>. Similarly, should the outer end of the vane <NUM> or rear insert <NUM> becomes clogged or partially clogged, the outer group of the impingement cooling apertures <NUM> may receive cooling air from the inner section 41B of the rear insert <NUM> via the flow passage(s) <NUM>.

In some embodiments, the cooling air flowing within the flow passages <NUM> between the outer section 41A and the inner section 41B of the rear insert <NUM> may induce vibrations of the tip 43B of the splitter plate <NUM>. It may not be possible to simply increase a thickness of the splitter plate <NUM> because a thicker splitter plate may interfere with some of the impingement cooling apertures <NUM>. In the present embodiment, to at least partially alleviate this issue, a perimeter of the tip 43B of the splitter plate <NUM> is secured to the rear insert <NUM> at at least one location L1. By securing the tip 43B of the splitter plate <NUM> as such vibrations and dynamic concerns may be at least partially addressed. The splitter plate <NUM> of the present embodiment may therefore be free of a cantilevered section because its perimeter is secured to the rear insert <NUM> at the at least one location L1.

In the embodiment shown, the tip 43B extends from a proximal end 43C at the base 43A to a distal end 43D. The distal end 43D may be secured to the rear insert <NUM>. In the embodiment shown, the distal end 43D is secured to the rear insert <NUM> at the at least one location L1 via a brazed or weld joint <NUM>. The rear end 41C of the rear insert <NUM> is proximate the trailing edge 31D of the vane <NUM> and the fore end 41D is proximate the rib <NUM> (<FIG>). The at least one location L1 may be at the fore end 41D of the rear insert <NUM>. The tip 43B of the splitter plate <NUM> may be free of attachment to the rear insert <NUM> at locations registering with the flow passages <NUM>.

Put differently, the tip 43B of the splitter plate <NUM> has a perimeter that may define a free portion 43E being free of abutment with the rear inserts <NUM> to define the flow passages <NUM> between the free portion 43E of the perimeter of the tip 43B and the rear insert <NUM>, and an attached portion 43F secured to the rear insert <NUM>. In the present embodiment, the free portion 43E includes two free portions 43E each on opposite sides of the tip 43B and each facing a respective one of the two flow passages <NUM>. The attached portion 43F may correspond to the distal end 43D of the tip 43B. An entirety of a perimeter of the distal end 43D of the tip 43B may be brazed to the rear insert <NUM>. Alternatively, the perimeter of the distal end 43D of the tip 43B may be brazed to the rear insert <NUM> at one or more discrete locations separated from one another.

In some embodiments, the tip 43B of the splitter plate <NUM> may be secured at any suitable locations that may avoid undesired vibrations of the tip 43B. This may include one or more attachment points between the distal end 43D of the tip 43B and the rear insert <NUM>; attachment points between lateral sides of the tip 43B and the rear insert <NUM> to decrease an effective length of a cantilevered portion of the tip 43B; and so on.

Securing the tip 43B of the splitter plate <NUM> as described herein may at least partially reduce the vibrations and dynamic issues of said splitter plate <NUM>. The splitter plate <NUM> may therefore have a longer lifespan. The stator <NUM> may have improved performance.

The principles of the present disclosure may also apply to the front insert <NUM>. In other words, the front insert <NUM> may, in some embodiments, require a front splitter plate, which may present the same characteristics of the splitter plate <NUM> described herein. The inserts <NUM> described herein may be replaced by two inserts being closed at one end, and welded in the vanes <NUM> to create two separate cavities instead of using a splitter plate. The splitter plates <NUM> may be at any suitable spanwise positions within the rear inserts <NUM>.

Claim 1:
A stator (<NUM>) of a turbine section (<NUM>), comprising:
vanes (<NUM>) circumferentially distributed around a central axis (A), a vane of the vanes (<NUM>) extending along a spanwise axis from a first end (31A) to a second end (31B), the vane defining an internal passage (31F) extending from the first end (31A) to the second end (31B);
an insert (<NUM>) received within the internal passage (31F) of the vane (<NUM>), the insert (<NUM>) defining a cavity for receiving cooling air, the insert (<NUM>) defining impingement cooling apertures (<NUM>) in fluid communication with the cavity and facing an inner face (31I) of the vane (<NUM>);
a splitter plate (<NUM>) secured within the cavity of the insert between the first end (31A) and the second end (31B) and being transverse to the spanwise axis,
characterized in the splitter plate (<NUM>) having a base (43A) secured to the insert (<NUM>) and a tip (43B) protruding from the base (43A); and
a flow passage (<NUM>) defined between the tip (43B) of the splitter plate (<NUM>) and the insert (<NUM>), the flow passage (<NUM>) fluidly connecting a first section (41A) of the cavity located on a first side of the splitter plate (<NUM>) to a second section (41B) of the cavity located on a second side of the splitter plate (<NUM>),
the tip (43B) of the splitter plate (<NUM>) secured to the insert (<NUM>) at at least one location along a perimeter of the tip (43B).