EP3663522A1

EP3663522A1 - Stator assembly for a gas turbine and gas turbine comprising said stator assembly

Info

Publication number: EP3663522A1
Application number: EP18425095.9A
Authority: EP
Inventors: Francesco BAVASSANO; Marco TAPPANI
Original assignee: Ansaldo Energia SpA
Current assignee: Ansaldo Energia SpA
Priority date: 2018-12-07
Filing date: 2018-12-07
Publication date: 2020-06-10
Anticipated expiration: 2038-12-07
Also published as: CN111287803B; CN111287803A; EP3663522B1; RU2019139258A

Abstract

A stator assembly (22) for a gas turbine comprising:
a stator ring (24), which extends about a longitudinal axis (A) and comprises an outer edge (29) provided with an annular groove (30); the annular groove (30) defining a leading edge wall (34) and a trailing edge wall (35); the leading edge wall (34) being provided with an annular leading edge radial face (56) and with an annular leading edge axial face (57); a plurality of stator vanes (25) radially arranged and coupled alongside one another to the outer edge (29) of the stator ring (24) so as to close the annular grove (30) and define an annular cooling channel (32); each stator vane (25) comprises an airfoil (38), an outer shroud (39) and an inner shroud (40) coupled to the stator ring (24); the inner shroud (40) comprising a platform (42) and a leading edge flange (43) and a trailing edge flange (44) extending radially inward from the platform (42); the leading edge flange (43) being coupled to the leading edge wall (34) and the trailing edge flange (44) being coupled to the trailing edge wall (35); the leading edge flange (43) being coupled to the leading edge wall (34) so as to leave a primary radial gap (48) between the leading edge wall (34) and the platform (42) and define a leading edge surface (50) of the leading edge flange (43); the leading edge flange (43) being provided, on the leading edge surface (50), with at least one primary cooling hole (55) in fluid communication with the annular cooling channel (32); the leading edge wall (34) comprising a primary baffle (59) protruding radially from the annular leading edge axial face (57) and axially facing the at least one primary cooling hole (55) .

Description

TECHNICAL FIELD

The present invention relates to a stator assembly for a gas turbine and to a gas turbine comprising said stator assembly. In particular, the gas turbine of the present invention is part of a plant for the production of electrical energy.

BACKGROUND

As is known, a gas turbine for power plants comprises a compressor, a combustor and a turbine.
In particular, the compressor comprises an inlet supplied with air and a plurality of rotating blades compressing the passing air. The compressed air leaving the compressor flows into a plenum, i.e. a closed volume delimited by an outer casing, and from there into the combustor. Inside the combustor, the compressed air is mixed with at least one fuel and combusted. The resulting hot gas leaves the combustor and expands in the turbine. In the turbine the hot gas expansion moves rotating blades connected to a rotor, performing work.
Both the compressor and the turbine comprise a plurality of stator assemblies axially interposed between rotor assemblies.
Each rotor assembly comprises a rotor disk rotating about a main axis and a plurality of blades supported by the rotor disk.
Each stator assembly comprises a plurality of stator vanes supported by a respective vane carrier and a stator ring arranged about the rotor.
A plurality of inter-assembly cavities are defined between the stator assemblies and the rotor assemblies.
In the turbine, sealing air is normally bled from the compressor and introduced in said inter-assembly cavities in order to avoid or limit the hot gas ingestion from the hot gas path in the inter-assemblies cavities.
The minimization of the amount of air spent to seal and cool the inter-assembly cavities is beneficial to the power plant performance. However, said minimization implies the use of expensive advanced materials and/or the adoption of arrangements having a very complex geometry.

SUMMARY

The object of the present invention is therefore to provide a stator assembly for a gas turbine, which enables avoiding or at least mitigating the described drawbacks.
In particular, it is an object of the present invention to provide a stator assembly having an improved structure able to minimize the amount of sealing air and guaranteeing, at the same time, a sufficient protection from thermal damages.
According to said objects the present invention relates to a stator assembly for a gas turbine comprising:

a stator ring, which extends about a longitudinal axis A and comprises an outer edge provided with an annular groove; the annular groove defining a leading edge wall and a trailing edge wall; the leading edge wall being provided with an annular leading edge radial face and with an annular leading edge axial face;
a plurality of stator vanes radially arranged and coupled alongside one another to the outer edge of the stator ring so as to close the annular grove and define an annular cooling channel; each stator vane comprises an airfoil, an outer shroud and an inner shroud coupled to the stator ring; the inner shroud comprising a platform and a leading edge flange and a trailing edge flange extending radially inward from the platform; the leading edge flange being coupled to the leading edge wall and the trailing edge flange being coupled to the trailing edge wall; the leading edge flange being coupled to the leading edge wall so as to leave a primary radial gap between the leading edge wall and the platform and define a leading edge surface of the leading edge flange;
the leading edge flange being provided, on the leading edge surface, with at least one primary cooling hole in fluid communication with the annular cooling channel;
the leading edge wall comprising a primary baffle protruding radially from the annular leading edge axial face and axially facing the at least one primary cooling hole.

The presence of at least primary cooling hole in the leading edge flange improves the thermal status of the upper part of the inter-assembly leading edge cavity. In particular, the primary cooling hole improves the thermal status of the annular leading edge axial face of the leading edge wall which is normally made of a material having poorer properties as compared to the vane.
Instead of providing a lot of air as usually done in the prior art solutions, cooling air is provided where it is more needed.
Moreover, thanks to the presence of a baffle facing the primary cooling hole some hot gas can be ingested in the zone comprising the primary radial gap from the main hot gas flow. This zone, in fact, is sufficiently cooled by cooling air coming from the primary cooling holes and the baffle deflects the flow of hot gas air ingested outside the zone comprising the primary radial gap.
The ingestion of hot gas can therefore be accepted, purged by means of the primary cooling holes and deflected away by means of the primary baffle. This leads to less overall consumption of sealing air therefore improving the engine global performance and the thermal status and integrity of the components of the stator assembly.
In other words, instead of completely avoiding hot gas ingestion by using high flow rate of sealing air, the present invention allows to confine hot gas inlet in the upper part of the inter-assembly cavity.
According to an embodiment of the present invention, the stator assembly comprises a plurality of primary cooling holes circumferentially aligned. In this way the cooling air could be provided along a circumferential direction.
According to an embodiment of the present invention, the primary cooling holes are evenly distributed. In this way the cooling air in uniformly distributed.
According to an embodiment of the present invention, the primary cooling hole extends along a primary extension axis; on a longitudinal axial plane defined by the longitudinal axis and a radial direction orthogonal to the longitudinal axis and intersecting the primary extension axis, the angle defined by the projection of the primary extension axis on the longitudinal axial plane and the radial direction is preferably comprised between 80° and 135°, while on a circumferential plane defined by the longitudinal axis and a circumferential direction, which is orthogonal to the longitudinal axis and orthogonal to a radial direction orthogonal to the longitudinal axis, the angle defined by the projection of the primary extension axis on the circumferential plane and the axial direction is preferably comprised between 100° and 200°.
According to an embodiment of the present invention, the primary baffle has an inner face facing the at least one primary cooling hole and an outer face opposite to the inner face; the primary baffle protruding radially from the annular leading edge axial face so as the outer face is an extension of the annular leading edge radial face. In this way, the baffle is easy to make and creates a recirculation zone sufficiently large.
According to an embodiment of the present invention, the primary baffle has at least one rounded connection to the annular leading edge axial face, which is preferably concave. In this way the deflection of flow induced by the baffle is improved. Specifically, rounded connection allows the recirculating hot gas ingested to be blown out from the cavity to the main stream.
According to an embodiment of the present invention, the primary baffle has an inner face facing the at least one primary cooling hole and an outer face opposite to the inner face; wherein the primary baffle comprises at least one fin protruding axially from the outer face. In this way, the fin defines a sort of barrier for the entry of hot gas in the inter-assembly cavity. Moreover, the fin drives the hot gas in the recirculation zone towards the main flow in the gas turbine channel avoiding the entry of said hot gas in the inter-assembly cavity. According to an embodiment of the present invention, the primary baffle comprises at least one fin protruding from the outer face in a direction which forms, on a radial plane, an angle β with respect to the axial direction. In this way, the driving action of the fin on the hot gas in the recirculation zone towards the main flow is improved.
According to an embodiment of the present invention, the primary baffle is made integral with the stator ring. In this way the time and costs to realize the stator assembly are reduced.
According to an embodiment of the present invention, the primary baffle is made of a material different from the one of the stator ring. In this way the baffle can be made of a material having high thermomechanical properties with respect to the material used for realizing the stator ring.
According to an embodiment of the present invention, the trailing edge flange is coupled to the trailing edge wall so as to leave a secondary radial gap between the trailing edge wall and the platform and define a trailing edge surface of the trailing edge flange; the trailing edge flange being provided, on the trailing edge surface, with at least one secondary cooling hole in fluid communication with the annular cooling channel.
The presence of at least secondary cooling hole in the trailing edge flange improves the thermal status of the upper part of the inter-assembly trailing edge cavity.
According to an embodiment of the present invention, the trailing edge wall is provided with an annular trailing edge radial face and with an annular trailing edge axial face; the trailing edge wall comprising a secondary baffle protruding radially from the annular trailing edge axial face and axially facing the at least one secondary cooling hole. Thanks to the presence of a secondary baffle facing the secondary cooling hole some hot gas can be ingested in the zone comprising the secondary radial gap from the main hot gas flow. This zone, in fact, is sufficiently cooled by cooling air coming from the secondary cooling holes. Moreover the secondary baffle deflects the flow of hot gas air ingested outside the zone comprising the secondary radial gap.
The ingested hot gas is therefore purged by the cooling hole and then expelled by means of the secondary baffle.
It is also an object of the present invention to provide a gas turbine which is reliable and wherein the consumption of sealing air is reduced. According to said objects the present invention relates to a gas turbine as claimed in claim 15.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described with reference to the accompanying drawings, which illustrate some non-limitative embodiment, in which:

Figure 1 is a schematic sectional front view, with parts removed for clarity, of a gas turbine electric power plant according to the present invention;
Figure 2 is a schematic sectional front view, with parts removed for clarity, of a first detail of Figure 1;
Figure 3 is a schematic perspective view, with parts in section and parts removed for clarity, of a second detail of Figure 1;
Figure 4 is a schematic sectional lateral view, with parts removed for clarity, of a third detail of Figure 1;
Figure 5 is a schematic up view, with parts in section and parts removed for clarity, of the third detail of Figure 4;
Figure 6 is a schematic sectional lateral view, with parts removed for clarity, of the detail of figure 4 according to a first variant of the present invention;
Figure 7 is a schematic sectional lateral view, with parts removed for clarity, of the detail of figure 4 according to a second variant of the present invention;
Figure 8 is a schematic sectional lateral view, with parts removed for clarity, of the detail of figure 4 according to a third variant of the present invention.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

In figure 1 reference numeral 1 indicates a gas turbine electric power plant (schematically shown in Figure 1).
The plant 1 comprises a compressor 3, a combustion chamber 4, a gas turbine 5 and a generator (for simplicity, not show in the attached figures).
The compressor 3, turbine 5 and generator (not shown) are mounted on the same shaft to form a rotor 8, which is housed in stator casings 9 and extends along an axis A.
In greater detail, the rotor 8 comprises a front shaft 10, a plurality of rotor assemblies 11 and a rear shaft 13.
Each rotor assembly 11 comprises a rotor disk 15 and a plurality of rotor blades 16 coupled to the rotor disk 15 and radially arranged.
The plurality of rotor disks 15 are arranged in succession between the front shaft 10 and the rear shaft 13 and preferably clamped as a pack by a central tie rod 14. As an alternative, the rotor disks may be welded together.
A central shaft 17 separates the rotor disks 15 of the compressor 3 from the rotor disks 15 of the turbine 5 and extends through the combustion chamber 4.
Further, stator assemblies 22 are alternated with the compressor rotor assemblies 11.
Each stator assembly 22 comprises a stator ring 24 and a plurality of stator vanes 25, which are radially arranged and coupled to the stator ring 24 and to the respective stator casing 9.
In figure 2 an enlarged view of a stator assembly 22 between two rotor assemblies 11 in the turbine 5 is shown.
Arrow D indicates the direction of the hot gas flow flowing in the turbine 5.
Between the rotor assemblies 11 and the stator assembly 22 inter-assembly cavities 27 are arranged.
In particular, each stator assembly 22 defines a leading edge inter-assembly cavity 27a and a trailing edge inter-assembly cavity 27b, wherein the leading edge inter-assembly cavity 27a is upstream the trailing edge inter-assembly cavity 27b along the hot gas flow direction D.
With reference to figure 3, the stator ring 24 (only a part of which is visible in figure 3) extends about the longitudinal axis A and comprises an inner edge 28 and an outer edge 29, which is provided with an annular groove 30.
The plurality of stator vanes 25 are coupled alongside one another to the outer edge 29 of the stator ring 24 so as to close the annular groove 30 and define an annular cooling channel 32.
The annular cooling channel 32 is fed with air preferably coming from the compressor 3.
The annular groove 30 defines a leading edge wall 34 and a trailing edge wall 35. The leading edge wall 34 is upstream the trailing edge wall 35 along the hot gas flow direction D.
Preferably, the leading edge wall 34 is provided with a plurality of cooling openings 36 in fluidic communication with the annular cooling channel 32.
Preferably, the cooling openings 36 are arranged in the proximity of the inner edge 28.
In the non-limiting example here disclosed and illustrated, the cooling openings 36 are circumferentially aligned and evenly distributed.
According to a variant not illustrated, also the trailing edge wall is provided with the cooling openings in fluidic communication with the annular cooling channel.
Each stator vane 25 comprises an airfoil 38, an outer shroud 39 and an inner shroud 40 coupled to the stator ring 24.
The airfoil 38 is provided with a cooling air duct 41a fed by a dedicated opening 41b on the outer shroud 39.
The outer shroud 39 is coupled to the respective stator casing 9.
The inner shroud 40 comprises a platform 42, a leading edge flange 43 and a trailing edge flange 44 extending radially inward from the platform 42. The leading edge flange 43 is upstream the trailing edge flange 44 along the hot gas flow direction D.
The leading edge flange 43 is coupled to the leading edge wall 34, while the trailing edge flange 44 is coupled to the trailing edge wall 35. In the non-limiting example here disclosed and illustrated, the leading edge flange 43 engages a respective annular seat 46 of the leading edge wall 34, while the trailing edge flange 44 engages a respective annular seat 47 of the trailing edge wall 35.
In particular, the leading edge flange 43 is coupled to the leading edge wall 34 so as to leave a primary radial gap 48 between the leading edge wall 34 and the platform 42 and to define a leading edge surface 50 of the leading edge flange 43 facing said primary radial gap 48.
Preferably, also the trailing edge flange 44 is coupled to the trailing edge wall 35 so as to leave a secondary radial gap 52 between the trailing edge wall 35 and the platform 42 and to define a trailing edge surface 53 of the trailing edge flange 44 facing said secondary radial gap 52.
The leading edge flange 43 is provided, on the leading edge surface 50, with at least one primary cooling hole 55 in fluid communication with the annular cooling channel 32.
Preferably, the leading edge flange 43 is provided, on the leading edge surface 50, with a plurality of primary cooling holes 55 circumferentially aligned.
In the non-limiting example here disclosed and illustrated, the primary cooling holes 55 are evenly distributed.
With reference to figure 4, each primary cooling hole 55 extends along a primary extension axis O.
On a longitudinal axial plane defined by the longitudinal axis and a radial direction orthogonal to the longitudinal axis and intersecting the primary extension axis, an angle α is defined by the projection of the primary extension axis Op on the longitudinal axial plane A-R and the radial direction R. Preferably the angle α of the primary cooling holes 55 is comprised between 80° and 135°.
With reference to figure 5 on a circumferential plane defined by the longitudinal axis A and a circumferential direction C, which is orthogonal to the longitudinal axis A and orthogonal to the radial direction R (in turn orthogonal to the longitudinal axis A), an angle is defined by the projection of the primary extension axis Op on the circumferential plane A-C and the axial direction A. preferably, the angle θ is comprised between 100° and 200°.
Preferably, the primary cooling holes 55 have different angles α and/or different angles θ.
According to a variant, primary cooling holes can be substantially identical to each other.
With reference to figure 3 and 4, the leading edge wall 34 is provided with an annular leading edge radial face 56 and with an annular leading edge axial face 57.
The leading edge wall 34 comprises a primary baffle 59 protruding radially outward from the annular leading edge axial face 57 and axially facing the at least one primary cooling hole 55.
The radial height w of the primary baffle 59 is comprised between 1% and 60% of a reference radial distance RF defined by the radial distance between the outer axial surface 58 of the platform 42 and the annular leading edge axial face 57.
In the non-limiting example here disclosed and illustrated, the primary baffle 59 has an inner face 60 facing the at least one primary cooling hole 55 and an outer face 61 opposite to the inner face 50.
Preferably, the primary baffle 59 protrudes radially from the annular leading edge axial face 57 so as the outer face 61 is an extension of the annular leading edge radial face 56.
In the non-limiting example here illustrated, the primary baffle 59 has at least one connection 63, preferably rounded, connecting the primary baffle 59 to the annular leading edge axial face 57. Preferably, the rounded connection 63 is concave.
According to a variant not illustrated, the connection is not rounded and has a triangular section along the longitudinal axial plane.
In the non-limiting example here disclosed and illustrated, the primary baffle 59 is made integral with the stator ring 24.
According to a variant not illustrated, the primary baffle and the stator ring are separate pieces coupled together. In this way, each piece can be replaced if required. Moreover, the primary baffle can be made of a material different from the one of the stator ring. For example, the primary baffle can be made of a material having higher thermomechanical properties with respect to the material of the stator ring. Alternatively, the primary baffle and the stator ring can be separate pieces made of the same material.
According to a further variant not illustrated, the stator ring could be coated with a specific material in order to improve its thermomechanical resistance.
With reference to figure 4, the radial distance S between the extension axis O of each primary cooling hole 55 and the annular leading edge axial face 57 is comprised between the 1% and the 40% of the reference radial distance RF defined by the radial distance between the outer axial surface 58 of the platform 42 and the annular leading edge axial face 57. It has to be considered, however, that the radial distance S should obviously have a value that allows the perforation of the leading edge surface 50.
The radial distance h between the lower point of the outlet of each primary cooling hole 55 and the annular leading edge axial face 57 is comprised between the 0% and the 20% of the reference radial distance' RF defined by the radial distance between the outer axial surface 58 of the platform 42 and the annular leading edge axial face 57.
With the expression "lower point of the outlet of each primary cooling hole" is intended the point having the minimum radial distance from the longitudinal axis at the outlet of the primary cooling hole 55; wherein the outlet is the terminal of the primary cooling hole 55 facing the primary baffle 59.
In figure 6 is illustrated a variant of the present invention wherein the primary baffle 59 comprises at least one fin 65 protruding axially from the outer face 61.
In figure 7 is illustrated another variant of the present invention wherein the primary baffle 59 comprises at least one fin 66 protruding from the outer face 61 in a direction which forms, on a radial plane A-R defined by the longitudinal axis A and a radial direction R orthogonal to the longitudinal axis A, an angle β with respect to the axial direction. Preferably angle β is lower than 90°.
In figure 8 is illustrated another variant of the present invention wherein the trailing edge flange 44 is provided, on the trailing edge surface 53, with at least one secondary cooling hole 68 in fluid communication with the annular cooling channel 32.
Preferably, the trailing edge flange 44 is provided, on the trailing edge surface 53, with a plurality of secondary cooling holes 68 circumferentially aligned.
In the non-limiting example here disclosed and illustrated, the secondary cooling holes 68 are evenly distributed.
According to the non-limitative embodiment here disclosed and illustrated, the secondary cooling holes 68 have a passage section smaller than the passage section of the primary cooling holes 55.
The trailing edge wall 44 is also provided with an annular trailing edge radial face 70 and with an annular trailing edge axial face 71.
The trailing edge wall 44 comprises a secondary baffle 73 protruding radially from the annular trailing edge axial face 71 and axially facing the at least one secondary cooling hole 68.
In the non-limiting example here disclosed and illustrated, the secondary baffle 73 has an inner face 75 facing the at least one secondary cooling hole 68 and an outer face 76 opposite to the inner face 75.
Preferably, the secondary baffle 73 protrudes radially from the annular trailing edge axial face 71 so as the outer face 76 is an extension of the annular trailing edge radial face 70.
In the non-limiting example here illustrated, the secondary baffle 73 has at least one rounded connection 78 to the annular trailing edge axial face 71. Preferably, the rounded connection 78 is concave.
In the non-limiting example here disclosed and illustrated, the secondary baffle 73 is made integral with the stator ring 24.
According to a variant not illustrated, the secondary baffle and the stator ring are separate pieces coupled together.
According to a variant not illustrated, the secondary baffle comprises at least one fin protruding axially from the outer face 76.
According to a variant not illustrated, the secondary baffle comprises at least one fin protruding from the outer face 76 in a direction which forms, on a radial plane A-R defined by the longitudinal axis A and a radial direction R orthogonal to the longitudinal axis A, an angle with respect to the axial direction, which is preferably lower than 90°.
Finally, it is clear that modifications and variants can be made to the stator assembly and to the gas turbine described herein without departing from the scope of the present invention, as defined in the appended claims.

Claims

Stator assembly (22) for a gas turbine comprising:
a stator ring (24), which extends about a longitudinal axis (A) and comprises an outer edge (29) provided with an annular groove (30); the annular groove (30) defining a leading edge wall (34) and a trailing edge wall (35); the leading edge wall (34) being provided with an annular leading edge radial face (56) and with an annular leading edge axial face (57);

a plurality of stator vanes (25) radially arranged and coupled alongside one another to the outer edge (29) of the stator ring (24) so as to close the annular grove (30) and define an annular cooling channel (32); each stator vane (25) comprises an airfoil (38), an outer shroud (39) and an inner shroud (40) coupled to the stator ring (24); the inner shroud (40) comprising a platform (42) and a leading edge flange (43) and a trailing edge flange (44) extending radially inward from the platform (42); the leading edge flange (43) being coupled to the leading edge wall (34) and the trailing edge flange (44) being coupled to the trailing edge wall (35); the leading edge flange (43) being coupled to the leading edge wall (34) so as to leave a primary radial gap (48) between the leading edge wall (34) and the platform (42) and define a leading edge surface (50) of the leading edge flange (43);

the leading edge flange (43) being provided, on the leading edge surface (50), with at least one primary cooling hole (55) in fluid communication with the annular cooling channel (32) ;

the leading edge wall (34) comprising a primary baffle (59) protruding radially from the annular leading edge axial face (57) and axially facing the at least one primary cooling hole (55).
Stator assembly according to anyone of the foregoing claims, comprising a plurality of primary cooling holes (55) circumferentially aligned.
Stator assembly according to claim 2, wherein the primary cooling holes (55) are evenly distributed.
Stator assembly according to anyone of the foregoing claims, wherein the primary cooling hole (55) extends along a primary extension axis (O); on a longitudinal axial plane (A-R) defined by the longitudinal axis (A) and a radial direction (R) orthogonal to the longitudinal axis (A) and intersecting the primary extension axis (O), a first angle (α) defined by the projection of the primary extension axis (O_P) on the longitudinal axial plane (A-R) and the radial direction (R) is comprised between 80° and 135°.
Stator assembly according to anyone of the foregoing claims, wherein the primary cooling hole (55) extends along a primary extension axis (O); on a circumferential plane defined by the longitudinal axis (A) and a circumferential direction (C), which is orthogonal to the longitudinal axis (A) and orthogonal to a radial direction (R) in turn orthogonal to the longitudinal axis (A), a second angle (θ) is defined by the projection of the primary extension axis (Op) on the circumferential plane and the axial direction (A) is comprised between 100° and 200°.
Stator assembly according to anyone of the foregoing claims, wherein the primary baffle (59) has an inner face (60) facing the at least one primary cooling hole (55) and an outer face (61) opposite to the inner face (60); the primary baffle (59) protruding radially from the annular leading edge axial face (57) so as the outer face (61) is an extension of the annular leading edge radial face (56).
Stator assembly according to anyone of the foregoing claims, wherein the primary baffle (59) has at least one rounded connection (63) to the annular leading edge axial face (57).
Stator assembly according to claim 7, wherein the rounded connection (63) is concave.
Stator assembly according to anyone of the foregoing claims, wherein the primary baffle (59) has an inner face (60) facing the at least one primary cooling hole (55) and an outer face (61)' opposite to the inner face (60); wherein the primary baffle (59) comprises at least one fin (65) protruding axially from the outer face (61).
Stator assembly according to anyone of claims from 1 to 8, wherein the primary baffle (59) has an inner face (60) facing the at least one primary cooling hole (55) and an outer face (61) opposite to the inner face (60); the primary baffle (59) comprises at least one fin (65) protruding from the outer face (61) in a direction which forms, on a radial plane, a third angle (β) with respect to the axial direction (A); the angle (β) being preferably lower than 90°.
Stator assembly according to anyone of the foregoing claims, wherein the primary baffle (59) is made integral with the stator ring (24).
Stator assembly according to anyone of the foregoing claims, wherein the primary baffle (59) is made of a material different from the one of the stator ring (24).
Stator assembly according to anyone of the foregoing claims, wherein the trailing edge flange (44) is coupled to the trailing edge wall (35) so as to leave a secondary radial gap (52) between the trailing edge wall (35) and the platform (42) and define a trailing edge surface (53) of the trailing edge flange (44); the trailing edge flange (44) being provided, on the trailing edge surface (53), with at least one secondary cooling hole (68) in fluid communication with the annular cooling channel (32).
Stator assembly according to claim 14, wherein the trailing edge wall (35) is provided with an annular trailing edge radial face (70) and with an annular trailing edge axial face (71); the trailing edge wall (35) comprising a secondary baffle (73) protruding radially from the annular trailing edge axial face (71) and axially facing the at least one secondary cooling hole (68).
Gas turbine extending along a longitudinal axis (A) and comprising:
a plurality of rotor assemblies (11), each of which comprises a rotor disk (15) and a plurality of rotor blades (16) radially arranged and coupled to the rotor disk (15);

a plurality of stator assemblies (22); the stator assemblies (22) and the rotor assemblies (11) are alternated along the axial direction (A);

at least one of the stator assemblies (22) being of the type claimed in anyone of the foregoing claims.