Diffuser strut cover, exhaust diffuser with such diffuser strut cover and associated gas turbine

Abstract

Diffuser strut cover (100), comprising: a. an upper portion (102), a lower portion (104), a pressure side portion (106), a suction side portion (108), an inner surface (112) and an outer surface (114), the pressure side portion (106) and the suction side portion (108) extending between the upper portion (102) and the lower portion (104); b. a flow distributor (116) defined at least partially between the pressure side section (106) and the suction side section (108); and c. a plurality of openings (124) arranged along the suction side section (108), the plurality of openings (124) being in fluid communication with the flow distributor (116); characterized in that the diffuser strut shroud (100) further comprises an upper plate (118) extending along the inner surface (112) between the pressure side section (106) and the suction side section (108) proximate the upper section (102), and a lower plate (120) extending along the inner surface (112) between the pressure side section (106) and the suction side section (108) proximate the lower section (104), the upper plate (118) and the lower plate (120) at least partially defining the flow distributor (116).

Description

FIELD OF THE INVENTION

[0001] The present invention generally relates to a diffuser strut for an exhaust diffuser of a gas turbine. More specifically, the present invention relates to a diffuser strut cover that at least partially surrounds the diffuser strut, an exhaust diffuser having such a diffuser strut cover, and a gas turbine. BACKGROUND OF THE INVENTION

[0002] Gas turbines are used extensively in industry and for power generation. A typical gas turbine includes a compressor section, a combustor downstream of the compressor section, and a turbine section downstream of the combustor. A working fluid, such as ambient air, flows into the combustor section, where it is compressed before flowing into the combustor. The compressed working fluid is mixed with a fuel and burned in the combustor to produce combustion gases at high temperature, high pressure, and high velocity. The combustion gases flow from the combustor and rapidly expand through the turbine section to drive a shaft and produce work. The combustion gases are then exhausted from the turbine section through an exhaust diffuser positioned downstream of the turbine section.

[0003] The exhaust diffuser typically includes an inner shell and an outer shell radially separated from the inner shell to form an exhaust flow channel through the diffuser. One or more substantially airfoil-shaped diffuser struts extend between the inner and outer shells within the exhaust flow channel to provide structural support for the outer shell and / or a rear bearing supporting the shaft. The aerodynamic performance of the exhaust diffuser is an important component of the overall gas turbine power output and heat consumption.

[0004] As the combustion gases flow through the exhaust flow channel and over the diffuser struts, the overall aerodynamic performance of the gas turbine is affected. Consequently, diffuser strut designs are typically optimized for baseload or full-speed / full-load operation of the gas turbine to improve gas turbine efficiency during regular and peak power requirements. However, the gas turbine may also operate in a part-load operating condition, resulting in increased swirl of the combustion gases leaving the turbine and entering the exhaust diffuser. The increased swirl triggers flow separation from one suction side of the diffuser struts, which impairs the aerodynamic performance of the gas turbine during part-load operation and also impacts the overall efficiency of the gas turbine.Therefore, an improved diffuser strut design would be useful in this field, reducing flow separation across the diffuser struts when the gas turbine operates outside of base load and / or full speed / full load operation.

[0005] DE 10 2012 100 373 A1 discloses a diffuser strut cover having the features of the preamble of patent claim 1, and further discloses an exhaust gas diffuser having such a diffuser strut cover and an associated gas turbine.

[0006] US 2009 / 0 263 243 A1 discloses an exhaust diffuser having a diffuser strut extending between the inner shell and the outer shell of the exhaust diffuser in the flow channel, the diffuser strut having a diffuser strut fairing extending around the leading edge of the diffuser strut, the diffuser strut fairing having a suction side portion, a flow distributor defined at least partially by the diffuser strut fairing, and a plurality of openings arranged along the suction side portion of the diffuser strut fairing, the plurality of openings being in fluid communication with the flow distributor.

[0007] Based on this, it is an object of the invention to at least partially eliminate the above-mentioned deficiencies and in particular to reduce the flow separation over the diffuser struts of an exhaust gas diffuser in a gas turbine, especially when the gas turbine operates outside of base load and / or full speed / full load operation. BRIEF DESCRIPTION OF THE INVENTION

[0008] To achieve the above object, the invention provides a diffuser strut cowling, an exhaust diffuser, and a gas turbine as defined in the claims. Aspects and advantages of the invention will be set forth in the following description or may be apparent from the description or learned by practicing the invention.

[0009] One embodiment of the present invention is a diffuser strut shroud. The diffuser strut shroud has an upper portion, a lower portion, a pressure side portion, a suction side portion, an inner surface, and an outer surface. The pressure side portion and the suction side portion extend between the upper portion and the lower portion. The diffuser strut shroud further includes a flow distributor defined at least partially between the pressure side portion and the suction side portion and a plurality of openings disposed along the suction side portion. The plurality of openings are in fluid communication with the flow distributor.The diffuser strut fairing further includes an upper plate extending along the inner surface between the pressure side portion and the suction side portion proximate the upper portion, and a lower plate extending along the inner surface between the pressure side portion and the suction side portion proximate the lower portion, the upper plate and the lower plate at least partially defining the flow distributor.

[0010] One or more of the plurality of openings of each aforementioned diffuser strut fairing may be angled with respect to a flow direction of a combustion gas flowing over the suction side portion.

[0011] The plurality of openings of each aforementioned diffuser strut shroud may be configured to create a boundary layer of compressed working fluid over at least a portion of the suction side portion.

[0012] The diffuser strut fairing of any type mentioned above may further include a fluid conduit providing fluid communication into the flow distributor.

[0013] The pressure side portion and the suction side portion of each of the above-mentioned diffuser strut fairings may overlap to form a leading edge portion extending between the upper portion and the lower portion.

[0014] Another embodiment of the present invention is an exhaust diffuser. The exhaust diffuser includes an outer shell radially separated from an inner shell and an exhaust flow channel defined therebetween. A diffuser strut extends between the inner shell and the outer shell in the exhaust flow channel. The diffuser strut includes a pressure side, a suction side, and a leading edge. The exhaust diffuser further includes a diffuser strut fairing according to the invention, as described above, extending around the leading edge of the diffuser strut, wherein the suction side portion of the diffuser strut fairing extends over a portion of the suction side of the diffuser strut.

[0015] One or more of the plurality of openings of each aforementioned exhaust diffuser may be angled with respect to a flow direction through the flow channel.

[0016] At least some of the plurality of openings of each aforementioned exhaust diffuser may be configured to provide a boundary layer of a compressed working fluid over at least a portion of the suction side of the diffuser strut.

[0017] The exhaust diffuser of any type mentioned above may further include a fluid conduit providing fluid communication into the flow distributor.

[0018] The flow distributor of each aforementioned exhaust diffuser may be at least partially defined between the diffuser strut cover and the diffuser strut.

[0019] The diffuser strut cover of each aforementioned exhaust diffuser may further include a pressure side portion extending along a portion of the pressure side of the diffuser strut.

[0020] The exhaust diffuser of any aforementioned type may further include a top plate extending between the diffuser strut shroud and the diffuser strut proximate an upper portion of the diffuser strut shroud, the top plate at least partially defining the flow distributor.

[0021] The exhaust diffuser of any aforementioned type may further include a lower plate extending between the diffuser strut shroud and the diffuser strut proximate a lower portion of the diffuser strut shroud, the lower plate at least partially defining the flow distributor.

[0022] The present invention also includes a gas turbine. The gas turbine includes a compressor section, a combustor section downstream of the compressor section, a turbine section downstream of the combustor section, and an exhaust diffuser according to the invention, as described above, arranged downstream of the turbine section.

[0023] One or more of the plurality of openings may be angled with respect to a flow direction through the flow channel.

[0024] At least some of the plurality of openings may be configured to provide a boundary layer of a compressed working fluid over at least a portion of the suction side of the diffuser strut.

[0025] The gas turbine of any type mentioned above may further include a compressed working fluid supply device in fluid communication with the flow distributor.

[0026] The flow distributor of each of the above-mentioned gas turbines may be at least partially defined between the diffuser strut shroud and the diffuser strut.

[0027] The gas turbine of any aforementioned type may further include a top plate extending between the diffuser strut shroud and the diffuser strut proximate an upper portion of the diffuser strut shroud to at least partially define the flow distributor.

[0028] Those skilled in the art will better understand the features and aspects of such embodiments and others upon reading the description. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] A complete and basic description of the present invention, including the best mode thereof for one skilled in the art, is set forth below in the remainder of the specification with reference to the accompanying figures, in which: Fig. 1 illustrates a cross-sectional side view of an exemplary prior art gas turbine that may incorporate various embodiments of the present invention; Fig. 2 is a simplified cross-sectional view downstream of an exemplary exhaust diffuser as shown in Fig. 1, which may include various embodiments of the present invention; Fig. 3 a cross-sectional plan view of an exemplary diffuser strut along a section line 3-3 as shown in Fig. 2 in accordance with various embodiments of the present invention; Fig. 4 a perspective view of two adjacent diffuser struts and a portion of an inner shell of the exhaust diffuser as shown in Fig. 3, in accordance with at least one embodiment of the present invention; Fig. 5 a cross-sectional plan view of one of the Fig. 4 with a diffuser strut cover according to at least one embodiment of the present invention; Fig. 6 a perspective rear view of the diffuser strut cover as shown in Fig. 4 and Fig. 5 in accordance with an embodiment of the present invention; Fig. 7 a perspective front view of the diffuser strut cover as shown in Fig. 4, Fig. 5 and Fig. 6 in accordance with an embodiment of the present invention; and Fig. 8 is a cross-sectional side view of a portion of the exhaust diffuser and a portion of the diffuser strut cover as shown in Fig. 4 in accordance with an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0030] Reference will now be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. The detailed description uses numerical and letter designations to refer to features in the drawings. The same or similar designations in the drawings or in the description have been used to refer to the same or similar parts of the invention. As used herein, the terms "first," "second," and "third" may be used interchangeably to distinguish one component from another and are not intended to indicate the location or significance of the individual components. The terms "upstream" and "downstream" refer to the relative direction with respect to the fluid flow in the fluid path. For example, "upstream" refers to the direction from which the fluid flows, and "downstream" refers to the direction in which the fluid flows.The term "radial" refers to the relative direction that is substantially perpendicular to an axial centerline of a particular component, and the term "axial" refers to the relative direction that is substantially parallel to an axial centerline of a particular component.

[0031] Each example is provided by way of illustration of the invention rather than limitation thereof. Indeed, it will be apparent to those skilled in the art that modifications and variations may be made in the present invention without departing from its scope or spirit. For example, features shown or described as part of one embodiment may be used in another embodiment to provide yet another embodiment of the invention. Thus, the present invention is intended to include such modifications and variations as fall within the scope of the appended claims and their equivalents.Although exemplary embodiments of the present invention are generally described in the context of an exhaust diffuser incorporated into an industrial gas turbine for illustrative purposes, one skilled in the art will readily recognize that embodiments of the present invention may be applied to any exhaust diffuser incorporated into any industrial gas turbine and are not limited to an industrial gas turbine unless otherwise stated in the claims.

[0032] In the drawings, in which identical reference numerals designate the same elements throughout the figures, Fig. 1 shows an example of a known gas turbine 10, as may embody various embodiments of the present invention. As illustrated, the gas turbine 10 generally includes a compressor section 12. The compressor section 12 includes a compressor 14. The compressor includes an inlet 16 located at an upstream end of the gas turbine 10. The gas turbine 10 further includes a combustion section 18 having one or more combustors 20 located downstream of the compressor section 12. The gas turbine further includes a turbine section 22 located downstream of the combustion section 18. A shaft 24 extends substantially axially through the gas turbine 10. The turbine section 22 includes alternating stages of stationary nozzles 26 and turbine rotor blades 28 disposed within the turbine section 20 along an axial centerline 30 of the shaft 24.An outer casing 32 circumferentially surrounds the alternating stages of stationary nozzles 26 and the turbine rotor blades 28. An exhaust diffuser 34 is arranged downstream of the turbine section 22.

[0033] In operation, ambient air or other working fluid (air 36) is drawn into the inlet 16 of the compressor 12 and progressively compressed to deliver compressed air 38 to the combustion section 18. The compressed air 38 flows into the combustion section 18 and is mixed with fuel to create a combustible mixture, which is burned in a combustion chamber 40 defined by each burner 20, thereby producing a hot gas 42 that flows from the combustion chamber 40 into the turbine section 22. The hot gas 42 rapidly expands as it flows through the alternating stages of stationary nozzles 26 and turbine rotor blades 28 of the turbine section 22.

[0034] Thermal and / or kinetic energy is transferred from the hot gases 42 to each stage of the turbine rotor blades 28, thereby rotating the shaft 24 and generating mechanical work. The hot gas 42 exits the turbine section 22 and flows through the exhaust diffuser 34 and over a plurality of substantially vane-shaped diffuser struts 44 disposed within the exhaust diffuser 34. During various gas turbine operating conditions, such as during part-load operation, the hot gas 42 flowing into the exhaust diffuser 34 from the turbine section 22 has a high degree of swirl caused by the rotating turbine rotor blades 28.As a result of the swirling hot gas 42 leaving the turbine section 22, flow separation of the hot gas 42 from the exhaust diffuser struts occurs, which impairs the aerodynamic operating behavior of the gas turbine 10 and thus the overall output power of the gas turbine and the heat consumption.

[0035] Fig. 2 illustrates a simplified downstream cross-sectional view of an exemplary exhaust diffuser 34 as may be used for the present invention. As illustrated, the exhaust diffuser 34 generally includes an inner shell 46 and an outer shell 48. The inner shell 46 extends substantially axially along an axial centerline 50 of the exhaust diffuser 34. The inner shell 46 is substantially annular and may at least partially surround rotating components. For example, the inner shell 46 may surround or enclose a portion of the shaft 24.

[0036] According to the presentation in Fig. 2, the outer shell 48 is radially separated from the inner shell 46. In certain embodiments, the inner shell 46 is concentrically and coaxially aligned within the outer shell 48 with respect to the axial centerline 50. An exhaust flow channel 52 is substantially defined between the inner shell 46 and the outer shell 48. In certain embodiments, the outer shell 48 may be a double-walled construction with an inner casing 54 radially separated from an outer casing 56. A compressed working fluid plenum 58 may be defined within the outer casing 56. For example, the compressed working fluid plenum 58 may be at least partially defined between the inner casing 54 and the outer casing 56. In further embodiments, the compressed working fluid plenum 58 may be defined within the inner casing 54.The present disclosure is not limited to any particular size, shape, material, or other physical characteristics of the inner shell 46, the outer shell 48, and / or the inner and outer housings 54, 56 except as stated in the claims.

[0037] According to the presentation in Fig. 2, each of the diffuser struts 44 extends between the inner shell 46 and the outer shell 48 in the exhaust flow channel 52 defined therebetween. The diffuser struts 44 are spaced circumferentially around the inner shell 46. The diffuser struts 44 substantially align the inner shell 46 with the outer shell 48. Additionally, the diffuser struts 44 may provide structural support between the inner and outer shells 46, 48. As shown in Fig. 1, the diffuser struts 44 are positioned with respect to a direction of flow 60 of the hot gas 42 flowing from the turbine region 22 of the gas turbine 10.

[0038] According to the presentation in Fig. 2, each diffuser strut 44 generally includes a base portion 62 connected to the inner shell 46 and a tip portion 64 radially separated from the base portion 60. The tip portion 64 may be connected to the outer shell 48 and / or the inner housing 54. In the context of the present invention, the term "diffuser strut" includes any structure or support member extending between the inner shell 46 and the outer shell 48 and / or the inner housing 54.

[0039] Fig. 3 illustrates a cross-section of an exemplary diffuser strut 44 along line 3-3 as shown in Fig. 2 in accordance with various embodiments of the present invention. As in Fig. 3, the diffuser strut 44 may be substantially airfoil-shaped. For example, the diffuser strut 44 includes a leading edge 66, a trailing edge 68 located downstream of the leading edge 66 with respect to the flow direction 60 of the hot gas 42, a pressure side 70, and a suction side 72 opposite the pressure side 70. It will be appreciated by those skilled in the art that the pressure side 70 and the suction side 72 may correspond to each other on opposite sides of the diffuser strut 44 depending on the direction of flow 60 of the hot gas 42 exiting the turbine section 22. In particular embodiments, the airfoil shape of the diffuser strut 44 may be defined at least in part by a skin or shroud (not shown) that at least partially surrounds the diffuser strut 44.

[0040] Fig. Figure 4 provides a perspective view of two adjacent diffuser struts 44 and a portion of the inner shell 46 according to at least one embodiment of the present invention. In specific embodiments, as shown in Fig. 4, a diffuser strut shroud 100 extends at least partially around each exhaust strut 44. The diffuser strut shroud 100 can be retrofitted to existing exhaust diffusers or can be incorporated into new diffuser strut designs. The diffuser strut shroud 100 includes an upper portion 102, a lower portion 104, a pressure side portion 106, and a suction side portion 108. The pressure side portion 106 and the suction side portion 108 extend between the upper portion 102 and the lower portion 104.

[0041] Fig. 5 is a cross-sectional plan view of one of the diffuser struts 44 with the diffuser strut cover 100 as shown in Fig. 4 in accordance with specific embodiments. As shown in the Fig. 4 and Fig. 5, the diffuser strut fairing 100 extends around the leading edge 66 of the diffuser strut 44. In particular embodiments, the diffuser strut fairing 100 extends around the leading edge 66 of the diffuser strut 44 from the pressure side 70 to the suction side 72. As shown, the pressure side portion 106 and the suction side portion 108 intersect to form a leading edge portion 110 that extends between the upper portion 102 and the lower portion 104 of the diffuser strut fairing 100. In particular embodiments, the leading edge portion 110 of the diffuser strut fairing 100 is substantially aligned with the leading edge 66 of the diffuser strut 44.

[0042] According to the presentation in Fig. 5, the diffuser strut shroud 100 includes an inner surface 112 and an outer surface 114. The inner surface 112 and the outer surface 114 extend between the pressure side portion 106, the suction side portion 108, the upper portion 102, and the lower portion 104 of the diffuser strut shroud. The pressure side portion 106 may extend at least partially over a portion of the pressure side 70 of the diffuser strut 44. The suction side portion 108 extends at least partially over the suction side 72 of the diffuser strut 44. The pressure side portion 106 may be immediately adjacent to the pressure side 70 of the diffuser strut 44. The suction side portion 108 may be immediately adjacent to the suction side 72 of the diffuser strut 44. In specific embodiments, the pressure side portion 106 is mechanically attached to the pressure side 70 of the diffuser strut 44, e.g., by brazing or welding.In special embodiments, the suction side section 108 is mechanically attached to the suction side of the diffuser strut 44, e.g., by brazing or welding.

[0043] In specific embodiments, the diffuser strut fairing 100 at least partially defines a flow distributor 116. The flow distributor 116 is at least partially defined by at least one of the pressure-side portion 106, the leading-edge portion 110, or the suction-side portion 108. The flow distributor 116 may be at least partially defined between the diffuser strut fairing 100 and the diffuser strut 44. For example, the flow distributor 116 may be at least partially defined between the inner surface 112 of the diffuser strut fairing 100 and a portion of the diffuser strut 44.

[0044] Fig. 6 is a perspective rear view of the diffuser strut cover as shown in Fig. 4 and Fig. 5 in accordance with an embodiment of the present invention. In an embodiment as shown in Fig. 6, the diffuser strut shroud 100 includes an upper plate 118 and a lower plate 120. The upper plate 118 is disposed substantially proximate the upper portion 102 of the diffuser strut shroud 100. The lower plate 120 is disposed substantially proximate the lower portion 104 of the diffuser strut shroud 100. In particular embodiments, the upper plate 118 and / or the lower plate 120 at least partially define the flow distributor 116. For example, in one embodiment, the upper plate 118 and / or the lower plate 120 extend between the inner surface 112 of the diffuser strut shroud 100 and the diffuser strut 44 to at least partially define the flow distributor 116.In further embodiments, the upper plate 118 and / or the lower plate 120 extend along the inner surface 112 between the pressure-side portion 106 and the suction-side portion 108 to at least partially define the flow distributor 116. At least one of the upper plate 118 or the lower plate 120 may include a flow channel 122 to create fluid communication into the flow distributor 116.

[0045] Fig. Figure 7 is a front perspective view of the diffuser strut cover 100 as shown in Figures Fig. 4, Fig. 5 and Fig. 6 in accordance with at least one embodiment of the present invention. In particular embodiments as shown in Fig. 5, Fig. 6 and Fig. 7, a plurality of openings 124 are arranged along the suction side portion 108 of the diffuser strut cover 100. In particular embodiments, at least some of the plurality of openings 124 are arranged near and / or adjacent to the leading edge 110 of the diffuser strut cover 100. As shown in Fig. 5, the openings 124 are in fluid communication with the flow distributor 116. During operation, a compressed working fluid 126, such as compressed air or steam, is directed from the flow distributor 116 through the openings 124 and along the suction side 108 of the diffuser strut shroud 100 and the suction side 72 of the diffuser strut 44.

[0046] At least some of the openings 124 may be configured to provide and / or reenergize a boundary layer of the hot gas 42 over the suction side portion 108 of the diffuser strut shroud 100 and / or over at least a portion of the suction side 72 of the diffuser strut 44 during various operating modes of the gas turbine 10, such as during part-load operation. For example, as shown in Fig. 7, at least some of the plurality of openings 124 extend substantially axially transverse to the suction side portion 108 of the diffuser strut shroud 100. The compressed working fluid 126 increases the flow velocity across the suction side portion 108 of the diffuser strut shroud 100 and / or the suction side 72 of the diffuser strut 44. Accordingly, flow separation of the hot gas 42 from the suction side 108 of the diffuser strut 44 may be delayed and / or prevented, thereby improving the overall operating performance of the gas turbine 10 and reducing the heat consumption of the gas turbine 10.

[0047] As in Fig. 7, at least a portion of the plurality of openings 124 may be arranged at an angle 128 with respect to a plane that extends substantially parallel to the axial centerline 50 of the exhaust diffuser 34 and / or with respect to the direction of flow 60 through the exhaust flow passage 52. The angle 128 may be either acute or obtuse to thereby direct the flow of the compressed working fluid 126 to the upper portion 102 of the diffuser strut shroud 100 or the tip portion 64 ( Fig. 2) the diffuser strut 44 or to direct the flow of the compressed working fluid 126 to the lower portion 104 of the diffuser strut cover 100 and / or the base portion 62 ( Fig. 2) to direct the diffuser strut 44.

[0048] Fig. Figure 8 provides a cross-sectional side view of a portion of the exhaust diffuser 34 including a portion of the inner housing 54, a portion of the outer housing 56, a portion of the compressed working fluid plenum 58 126, and a portion of the diffuser strut shroud 100. As shown in Figures Fig. 4 and Fig. 8, the diffuser strut shroud 100 may further include a fluid conduit 130 or coupling that provides fluid communication into the fluid manifold 116. In one embodiment, the fluid conduit 130 may be in fluid communication with the compressed working fluid plenum 58. In other embodiments, the fluid conduit 130 may be in fluid communication with an external compressed working fluid supply device 126 (not shown) via one or more fluid couplings.

[0049] During operation, particularly during part-load operation of the gas turbine, the compressed working fluid 126 is injected into the flow distributor 116. The compressed working fluid 126 is guided through the openings 124 along the suction side portion 108 of the diffuser strut shroud 100. The compressed working fluid 126 flows through the outer surface 114 of the suction side section 108 and the suction side 72 of the diffuser strut 44 at a relatively high velocity relative to the hot gas 42 flowing over the diffuser struts 44. The compressed working fluid 126 delays flow separation from the suction side 108 of the diffuser strut 44, thereby increasing the overall power output of the gas turbine 10 and / or reducing the heat consumption of the gas turbine 10. This increases a separation-free operating envelope of the exhaust struts 44, which improves the overall operating behavior of the gas turbine 10, particularly at part load or less than base load operating conditions.

[0050] This description uses examples to disclose the invention, including its best mode, and to enable any person skilled in the art to practice the invention, including making and using all elements and systems and performing all incorporated methods. The patentable scope of the invention is defined by the claims and may include other examples that would be apparent to one skilled in the art. Such other examples are intended to be included within the scope of the invention if they contain structural elements that do not differ from the language of the claims, or if they contain equivalent structural elements with insubstantial changes from the language of the claims.

[0051] A diffuser strut shroud includes an upper portion, a lower portion, a pressure side portion, a suction side portion, an inner surface, and an outer surface. The pressure side portion and the suction side portion extend between the upper portion and the lower portion. The diffuser strut shroud further includes a flow distributor defined at least partially between the pressure side portion and the suction side portion. A plurality of openings are arranged along the suction side portion and are in fluid communication with the flow distributor. LIST OF REFERENCE SYMBOLS 10 gas turbines 12 Compressor area 14 compressors 16 Entrance 18 Combustion area 20 burners 22 Turbine area 24 Wave 26 stationary guide nozzles 28 turbine rotor blades 30 Center line 32 outer casings 34 Exhaust diffuser 36 Air 38 compressed air 40 combustion chamber 42 Hot gas, hot gas 44 Diffuser strut 46 inner shell 48 Outer shell 50 axial midline 52 Exhaust flow channel 54 inner casing 56 outer casing 58 Assembly room 60 current 62 foot section 64 peak section 66 leading edge 68 trailing edge 70 printed pages 72 suction side 100 diffuser strut trim 102 upper section 104 lower section 106 Printed Page Section 108 Suction side section 110 Leading edge section 112 Interior surface 114 Exterior surface 116 flow distributors 118 upper plate 120 lower plate 122 flow channel 124 openings 126 compressed working fluid 128 angles 130 Fluid line

Claims

[1] Diffuser strut cover (100), comprising: a. an upper portion (102), a lower portion (104), a pressure side portion (106), a suction side portion (108), an inner surface (112) and an outer surface (114), the pressure side portion (106) and the suction side portion (108) extending between the upper portion (102) and the lower portion (104); b. a flow distributor (116) defined at least partially between the pressure side section (106) and the suction side section (108); and c. a plurality of openings (124) arranged along the suction side section (108), the plurality of openings (124) being in fluid communication with the flow distributor (116); characterized byin that the diffuser strut cover (100) further comprises an upper plate (118) extending along the inner surface (112) between the pressure side section (106) and the suction side section (108) near the upper section (102), and a lower plate (120) extending along the inner surface (112) between the pressure side section (106) and the suction side section (108) near the lower section (104), the upper plate (118) and the lower plate (120) at least partially defining the flow distributor (116). [2] The diffuser strut cover (100) of claim 1, wherein one or more of the openings (124) are arranged at an angle (128) with respect to a direction of flow (60) of a combustion gas flowing over the suction side portion (108). [3] The diffuser strut cover (100) of claim 1, wherein the plurality of openings (124) are configured to create a boundary layer of a compressed working fluid (126) over at least a portion of the suction side portion (108). [4] The diffuser strut cover (100) of claim 1, further comprising a fluid conduit (130) providing fluid communication into the flow distributor (116). [5] The diffuser strut fairing (100) of claim 1, wherein the pressure side portion (106) and the suction side portion (108) intersect to form a leading edge portion (110) extending between the upper portion (102) and the lower portion (104). [6] Exhaust diffuser (34), comprising: a. an outer shell (48) radially separated from an inner shell (46) and an exhaust gas flow channel (52) defined therebetween; b. a diffuser strut (44) extending between the inner shell (46) and the outer shell (48) in the exhaust flow channel (52), the diffuser strut (44) having a pressure side (70), a suction side (72) and a leading edge (66); c. a diffuser strut cover (100) according to any one of the preceding claims extending around the leading edge (66) of the diffuser strut (44), wherein the suction side portion (108) of the diffuser strut cover (100) extends over a portion of the suction side (72) of the diffuser strut (44). [7] Gas turbine (10), comprising: a compressor section (12); b. a combustion region (18) arranged downstream of the compressor region (12); c. a turbine region (22) arranged downstream of the combustion region (18); and d. an exhaust diffuser (34) according to claim 6, arranged downstream of the turbine region (22).

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