JPH04214932A - Gap seal structure between adjacent segments in circumferential direction of turbine nozzle and shround - Google Patents

Abstract

PURPOSE: To effectively seal the gap between the edges of two segment-form elements by providing an elastic spring clip which is engaged to the under-parts of the edges of the segments, overlapped on a seal member, and biases the seal member in the sealed contacting condition with the plane of each edge and in the gap sealing relation. CONSTITUTION: A structure to seal the gap between edges 52 of a pair of adjoining segments 54 comprises a pair of flanges 66 inclined in the opposite directions, a thin and long seal rod 70 in cylindrical form to block the gap in such a way as striding the inter-flange gap, and an elastic spring clip 72 having a channel-shaped section and capable of yielding. The clip 72 is engaged to the under-part of the edge flange and holds the seal rod in the sealed contacting condition with the plane of the edge flange. The edge parts of the spring clip on both sides are extending from around the edge flange to the under-part and the middle part of the spring clip has a shape to be identical to the shape of the side face part of the seal rod to be fitted.

Description

[Detailed description of the invention]

0001

TECHNICAL FIELD This invention relates generally to gas turbine engines, and more particularly to an improved structure for sealing gaps between adjacent circumferential segments of a turbine nozzle and shroud.

0002

BACKGROUND OF THE INVENTION The efficiency of gas turbine engines depends on many factors. One factor is the degree to which the high pressure cooling air generated in the compressor section of a gas turbine engine and used primarily to drive the turbine section of the engine is diverted to other uses of the engine. One such use of cooling air is to cool metal surfaces along the main core flow path and maintain them below melting temperature. The more cooling air that can be diverted to other uses within the engine, the less air is left to drive the turbine.
Therefore, the motion efficiency of the turbine deteriorates.

It is therefore important to limit the amount of cooling air diverted from turbine driving applications to only that amount absolutely necessary to perform such other auxiliary functions. Sealing structures have been proposed in the past to prevent such diverted air from being lost by leaking between adjacent segments of the engine element. Representative conventional examples include Bertelson U.S. Patent No. 3,728,041, Kildea U.S. Patent No. 4,311,432, Grosjean U.S. Patent No. 4,537,024, and Holowach et al. U.S. Patent No. No. 4,662,658, Miracourt et al., U.S. Pat. No. 4,759,687, and Cleveng et al.
There is a seal structure disclosed in US Pat. No. 4,767,260 to Er et al.

One conventional seal structure commonly used to seal gaps between adjacent segment edges of turbine nozzles and shrouds is called a spline seal structure. It is. The advantage of this structure is that it is simple to construct. However, this structure is susceptible to leakage whenever the geometry of the segment edges is no longer suitable as a result of the cutting method used, the tolerances adopted, misalignment of the segments, etc. It is not effective as a control mechanism. Therefore, there is a need for a structure that effectively seals gaps between segment edges while avoiding the problems described above.

[0005]

SUMMARY OF THE INVENTION The present invention provides an improved seal arrangement designed to meet the needs set forth above. The improved seal structure of this invention maintains an effective seal in the gap between adjacent segment edges at all times, even with limited movement or relative misalignment of the segment edges. It has the effect of Because of this ability, the improved seal structure of this invention seals gaps between adjacent segments of turbine nozzles and shrouds where thermal expansion and contraction of the segments can cause such relative movement and misalignment. It is particularly suitable for

[0006] Accordingly, this seal structure is effective in preventing cooling air from leaking through the gap into the main core flow path of the gas turbine engine. The invention is applicable to all turbine engines that use cooled segmented nozzles and shrouds. The improved seal structure of the present invention improves the efficiency of the turbine engine due to improved coolant sealing performance. The improved seal structure also has better segment edge wear characteristics and improved segment edge cooling.

Accordingly, the present invention provides a structure for sealing gaps between adjacent edges of segment-like elements, in which: a pair of oppositely inclined flanges; (b) a sealing member disposed between the flanges and seated on an oppositely inclined plane for spanning and closing the gap between the flange edges;
c) a yieldable elasticity secured to the underside of the flange, overlapping the sealing member and biasing the sealing member into sealing contact and clearance sealing relationship with the plane of the flange; A sealing structure with a spring clip is provided.

Specifically, the spring clip has a channel-like cross-sectional shape and includes a pair of opposite longitudinal edge portions and an intermediate portion interconnecting the opposing longitudinal edge portions. Both edge portions of the spring clip have a hook shape, one opposite in shape to the other, extending downwardly around the edge of the segment-like element. The intermediate portion of the clip overlaps and engages the seal member, and has a shape that matches the shape of the side portion of the seal member with which the intermediate portion of the clip engages.

Further, the seal member is an elongated straight rod having a curved portion that engages the plane of the flange of the segment edge. The sealing rod has a circular cross-sectional shape and makes substantially linear sealing contact with the plane of the flange.

In order to further clarify the above-mentioned and other features, effects and advantages of the present invention, the present invention will now be described in detail with reference to preferred embodiments illustrated in the accompanying drawings.

[0011]

[Specific Structure] In the following description, the same reference numerals in a series of drawings indicate the same or corresponding parts. In addition, in the following explanation, "front", "rear", "left", "right", "
Terms such as "upper" and "lower" are used for convenience.
It should not be considered a limiting term. General In FIG. 1, a gas turbine engine to which the present invention can be applied is shown, generally designated by 10. Engine 10 has an annular casing 12 coaxially and concentrically disposed about a longitudinal centerline or axis A. Engine 10 includes a core gas generator engine 14 that includes a compressor 16, a combustor 18, and a single or multi-stage high pressure turbine 20, all about a longitudinal axis or centerline A of engine 10. are arranged coaxially in series and in axial flow relationship. The annular drive shaft 22 is the compressor 1
6 and the high pressure turbine 20 are rigidly interconnected.

Core engine 14 functions to generate combustion gases. Compressed air from compressor 16 is mixed with fuel in combustor 18 and ignited, thus producing combustion gases. A high pressure turbine 20 extracts some work from the combustion gases, thereby driving the compressor 16. The remainder of the combustion gas is transferred from the core engine 14 to a low-pressure power turbine 24.
to be discharged.

Low pressure power turbine 24 includes an annular drum rotor 26 and a stator 28. The rotor 26 is rotatably mounted by suitable bearings 30 and includes a plurality of axially spaced rows 34 of turbine blades extending radially outwardly therefrom. Stator 28 is disposed radially outwardly of rotor 26 and includes a plurality of rows 36 of stator vanes affixed to stationary casing 12 and extending radially inwardly therefrom. Stator vane rows 36 are axially spaced apart and alternate with turbine blade rows 34. Rotor 26 is secured to drive shaft 38 and interconnected thereto via actuation bearing 32 .

On the other hand, the drive shaft 38 rotationally drives the front booster rotor 39. The front booster rotor 39 forms part of the booster compressor 40 and supports a front fan blade row 41, which is connected to the stationary casing 12. It is housed within a nacelle 42 that is supported around the circumference by a plurality of struts or posts 43 (only one shown). The booster compressor 40 is
a plurality of rows 44 of booster blades affixed to and extending radially outwardly therefrom and rotating therewith; and a plurality of rows 46 of extending booster stator vanes. Both the booster blade row 44 and the stator vane row 46 are spaced apart in the axial direction.
They are arranged in an alternating manner. Conventional Seal Structures Conventional seal structures commonly used in FIG. 2 are collectively indicated at 48. The conventional seal structure, referred to as a spline seal structure in the following description, is for preventing cooling air from leaking from the external cooling air side 14A of the core engine 14 to the internal flow path side 14B. The spline seal structure 48 extends between adjacent edges 52 of a plurality of circumferential segments 54 (only one pair shown) forming part of a nozzle and shroud (only a portion shown) of the gas turbine engine 10. are provided to seal each of a plurality of gaps 50 (only one is shown).

The clearance or gap 50 provides a passageway for cooling air to leak from the high pressure exterior side 14A of the core engine 14 to the low pressure interior side 14B. Typically, cooling air is directed at low velocity and high pressure toward an impingement baffle 56 overlying the segment 54 to be cooled. Air baffle 5
As the air accelerates as it passes through orifice 58 of 6, it impinges on the exterior side of segment 54 at a relatively high velocity which increases heat transfer from the segment.

To prevent cooling air from leaking through gap 50, spline seal structure 48 employs an elongated, thin, flat spline seal member 60. The spline seal member 60 is formed along both longitudinal edges 60A of the spline seal member 60 by grooves 6 formed in adjacent segment edges 52.
2, so as to straddle the gap 50 between the edges 52, and to tightly contact the lower surface 62A of the groove 62.

However, because the grooves 62 of adjacent segment edges 52 cannot be maintained in a coplanar relationship, the seal arrangement with the spline seal structure 48 is prone to leakage and is ineffective. The inability to maintain adjacent grooves 62 in coplanar alignment is due to machining tolerances and segment movement. Therefore, the spline seal member 60 does not properly seat and seal the groove 62, thereby creating a leakage path. Further, although the spline seal groove 62 is typically produced by electric discharge machining, the flat seal member 6
Roughness remains on the groove surface including the lower surface 62A on which the groove 0 contacts and seats. The rough lower surface 62A leads to a cooling air leakage path.

Additionally, the geometry that spline seal structure 48 forms at segment edge 52 makes efficient cooling difficult. Because of this cooling difficulty and increased turbine operating temperatures, segment edges 52 are susceptible to oxidative attack. Modification of conventional spline seal structures to improve cooling at the segment edges is limited by its unique seal geometry. Improved seal structure of this invention FIGS. 3 and 4 show a conventional spline seal structure 4.
An improved seal structure constructed in accordance with the present invention, which overcomes the problems discussed above with respect to 8, is indicated generally at 64. The improved seal structure 64 includes a pair of oppositely sloped flanges 66 on the edges 52 of the circumferential segments 54 that are typically spaced apart by a gap 50 . The flanges 66 each define a generally equal, oppositely sloped, flat upwardly facing surface 68 on the upper side.

Seal structure 64 also includes a seal member 70, preferably in the form of an elongated, generally linearly extending cylindrical rod 70. A cylindrical sealing rod 70 is disposed between and seated on the oppositely sloped flat surfaces 68 of the sloped flange 66 and is connected to the flange 66.
6 and close the gap 50 between them. The circular cross-sectional shape of rod 70 and the oppositely sloped orientation of flat surface 68 provide
A line contact is easily obtained between the curved portion 70A on each side of the rod 70 and the flat surface 68 to seal them both.

Seal structure 64 further includes a yieldable resilient spring clip 72. This clip 72 is locked to the lower side of the flange 66 and covers the seal rod 70 so that the seal rod 70 is in a sealed line contact relationship with the flat surface 68 of the flange 66 and in a sealed relationship with the gap 50 by straddling the gap 50. bias towards. Also shown in FIG. 3 is a cooling air impingement plate 74.
are also shown (holes omitted for convenience of illustration), but these impingement plates do not form part of the seal structure 64 of the present invention.

Spring clip 72 has a channel-like cross-sectional configuration and includes a pair of opposite longitudinal edge portions 72A and an intermediate portion 72B interconnecting the opposite edge portions 72A. As can be seen in FIG. 4, the opposite longitudinal edge portions 72A of the spring clip 72 are generally hook-shaped, one being the opposite of the other. Hook-shaped edge portion 72A extends from around edge flange 66 of segment 54 to the underside of edge portion 72A.
contacts the lower surface 69 of the flange 66 at its tip to anchor the spring clip 72 thereto. Lower surface 69 is also substantially planar and substantially parallel to upper planar surface 68 .

The intermediate portion 72B of the clip 72 overlies and engages the cylindrical seal rod 70. The clip intermediate portion 72B has an arcuate cross section that matches the curved shape of the upper side of the seal rod 70, and contacts the rod 70 there. The spring clip 72 deflects relatively easily and has relatively low stiffness, so it
Only a light load or bias is applied to the rod 70.

The flexibility of spring clip 72 retains seal rod 70 in a clevis formed by generally equal and oppositely sloped flat surfaces 68 of flange 66. Due to the fact that the planes of the inclined surfaces 68 always intersect each other under engine operating conditions, this seal structure remains relatively uniform even as the flanges move relative to each other. Thus, the segments 54 are free to move apart or angularly radially or circumferentially, yet the seal structure functions equally as if perfect alignment was maintained. As the clip 72 biases the rod 70 downwardly, the rod 70 moves up and down over the flange 66 as the flanges 66 move closer and further apart and the gap 50 narrows and widens accordingly. Can be moved. The edge portion 72A of the clip lip may be attached to the flange 6 depending on the expected operating conditions.
It may be slidably held on the lower surface 69 of 6 or may be fixed, and in either case, a sealing relationship is maintained.

It is clear that spring clip 72 and seal rod 70 need not be of the same length. The spring clip 72 can be shorter than the rod. Furthermore, by changing the cross-sectional shape of the clip, the magnitude of the seal biasing force can be changed. Additionally, the sealing surface of flange 66 can be manufactured by grinding, which provides a smooth surface finish that is more suitable for sealing, and which reduces the cost of manufacturing such a finish. The ends of the spring clips can be capped to prevent air leakage therefrom.

The configuration and effects of the present invention should be understood from the above description, and the shape, configuration, and arrangement of parts may be changed without departing from the gist of the present invention.
It will also be clear that various modifications may be made without sacrificing its important advantages. The embodiments described above are merely preferred or exemplary embodiments of the invention. for example,
The present invention seals not only circumferentially adjacent segments but also gaps between adjacent segments and can be easily adapted to seal.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a gas turbine engine.

FIG. 2 is a partial cross-sectional view of a conventional seal structure for sealing gaps between adjacent circumferential segments of a turbine nozzle and shroud.

FIG. 3 is a partial perspective view of an improved seal structure according to the present invention.

FIG. 4 is an enlarged cross-sectional view of the seal structure taken along line 4-4 in FIG. 3;

[Explanation of symbols]

50 gap, 52 edge, 54 segment,
64 Seal structure, 66 Inclined flange, 68
Inclined plane, 70 cylindrical rod, 72 spring clip, 72A edge section, 72B intermediate section.

Claims (21)

[Claims] Claim 1. In a structure for sealing a gap between adjacent edges of segment-like elements having planes inclined in opposite directions to each other, there is provided the following: (b) a sealing member seated on and spanning the gap between the edges and closing the gap; a sealing structure comprising a yieldable resilient spring clip biasing the clip into sealing contact and gap sealing relationship with the plane of said edge; 2. The segmented element is a circumferentially segmented element, and the spring clip has a pair of opposing longitudinal edge portions and an intermediate portion interconnecting the opposite edge portions. The seal structure according to claim 1, comprising: 3. A seam according to claim 2, wherein both edge portions of the spring clip have a hook shape, one opposite the other and extending downwardly around the edge of the segment-like element. le structure. 4. The clip according to claim 2, wherein an intermediate portion of the clip engages with the sealing member, and the intermediate portion of the clip has a shape that matches the shape of a side portion of the sealing member with which the clip is engaged. Seal structure as described. 5. The seal structure of claim 1, wherein said seal member is an elongated straight rod having a curved portion that engages the plane of said edge. 6. The seal structure of claim 5, wherein said seal rod has a circular cross-sectional shape and makes substantially linear sealing contact with the plane of said edge. 7. The seal structure according to claim 1, wherein the spring clip has a channel-like cross-sectional shape. 8. A seal structure in combination with a pair of spaced apart adjacent segments defining a gap between the edges, comprising: (a) defining planes located on the edges of the segments and sloped in opposite directions; a pair of flanges, (b)
a sealing member disposed between the edge flanges and seated on a plane inclined in the opposite direction, straddling the gap between the edges and sealably closing the gap; and (c) a lower side of the edge flange. The sealing member is engaged with the flat surface of the edge flange, overlaps the sealing member, and seals the sealing member with the plane of the edge flange.
A seal structure comprising a yieldable resilient spring clip that biases the seal into contact and into gap sealing relationship. 9. The seal structure of claim 8, wherein the spring clip includes a pair of opposite longitudinal edge portions and an intermediate portion interconnecting the opposite edge portions. 10. Both edge portions of the spring clip have a hook shape, one opposite in shape to the other, extending downwardly around the edge of the segment.
Seal structure described in . 11. An intermediate portion of the clip is attached to the seam.
a seal member that engages with the clip intermediate portion;
The seal structure according to claim 9, wherein the seal structure has a shape that matches the shape of the side portion of the seal member. 12. The seal structure of claim 8, wherein said seal member is an elongated straight rod having a curved portion that engages the plane of said edge. 13. The seal structure of claim 12, wherein said seal rod has a circular cross-sectional shape and makes substantially linear sealing contact with the plane of said edge. 14. The seal structure according to claim 8, wherein the spring clip has a channel-like cross-sectional shape. 15. A plurality of segments arranged circumferentially and spaced apart from each other, wherein the pressurized gas may flow from the high pressure side of the segment to the low pressure side of the segment through a gap defined between the adjacent segments. for use in a gas turbine engine, comprising: (a) a pair of oppositely sloped edge flanges located on said segment and defining oppositely sloped planes; (b) disposed between said edge flanges; (c) a sealing member that is seated on a plane inclined in the opposite direction and straddles the gap between the edge flanges and closes the gap; . A seal structure comprising a yieldable resilient spring clip biasing the seal member into sealing contact and gap sealing relationship with the plane of the edge flange. 16. The seal structure of claim 15, wherein the spring clip includes a pair of opposite longitudinal edge portions and an intermediate portion interconnecting the opposite edge portions. 17. Both edge portions of the spring clip have a hook shape, one opposite in shape to the other, extending downwardly around the edge of the segment.
The seal structure described in 6. 18. An intermediate portion of the clip is attached to the seam.
a seal member that engages with the clip intermediate portion;
17. The seal structure according to claim 16, wherein the seal structure has a shape that matches the shape of the side portion of the seal member. 19. The seal structure of claim 15, wherein said seal member is an elongated straight rod having a curved portion that engages the plane of said edge. 20. The seal structure of claim 19, wherein said seal rod has a circular cross-sectional shape and makes substantially linear sealing contact with the plane of said edge. 21. The seal structure according to claim 15, wherein the spring clip has a channel-like cross-sectional shape.