WO2020180294A1

WO2020180294A1 - Fuel injection nozzle including a heat shield

Info

Publication number: WO2020180294A1
Application number: PCT/US2019/020538
Authority: WO
Inventors: Charalambos POLYZOPOULOS; Richard L. THACKWAY
Original assignee: Siemens Energy, Inc.
Priority date: 2019-03-04
Filing date: 2019-03-04
Publication date: 2020-09-10

Abstract

A fuel injection nozzle for a gas turbine (10) includes a nozzle body (65) defining a longitudinal axis (35) and including a plurality of fuel openings (125) arranged annularly around the longitudinal axis, and a heat shield (135) coupled to the nozzle body (65). The heat shield (135) includes a central aperture (165), a plurality of fuel apertures (185) arranged annularly around the longitudinal axis, and a plurality of key slots (195) arranged annularly around the longitudinal axis, each key slot (195) extending through the heat shield (135) and extending from the central aperture (165) to one fuel aperture (185) of the plurality of fuel apertures (185).

Description

FUEL INJECTION NOZZLE INCLUDING A HEAT SHIELD

TECHNICAL FIELD

[0001] The present disclosure is directed, in general, to a fuel nozzle for a gas turbine engine, and more specifically to a fuel nozzle that includes a heat shield.

BACKGROUND

[0002] Operation of a gas turbine engine requires high-temperature combustion. The higher the temperature, the more efficient the operation of the turbine engine. Additionally, high temperature combustion can increase the level of undesirable emission gasses. However, the high-temperature combustion can cause damage to many components and materials used in the gas turbine engine.

SUMMARY

[0003] A fuel injection nozzle for a gas turbine includes a nozzle body defining a longitudinal axis and including a plurality of fuel openings arranged annularly around the longitudinal axis, and a heat shield coupled to the nozzle body. The heat shield includes a central aperture, a plurality of fuel apertures arranged annularly around the longitudinal axis, and a plurality of key slots arranged annularly around the longitudinal axis, each key slot extending through the heat shield and extending from the central aperture to one fuel aperture of the plurality of fuel apertures.

[0004] In another construction, a fuel injection nozzle for a gas turbine includes a nozzle body defining a longitudinal axis and including a plurality of fuel openings arranged annularly around the longitudinal axis, and a heat shield coupled to the nozzle body. The heat shield includes a central aperture, a plurality of fuel apertures arranged annularly around the longitudinal axis, and a plurality of key slots, each key slot including a first portion that extends in a non-radial direction with respect to the longitudinal axis from one of the plurality of fuel apertures toward the central aperture and a second portion that extends from the first portion to the central aperture.

[0005] In another construction, a heat shield for a gas turbine fuel injection nozzle includes a heat shield body including a frustoconical portion, a central aperture centered on a longitudinal axis, and an annular portion centered on and extending parallel to the longitudinal axis, a plurality of fuel apertures formed in the frustoconical portion and spaced annularly around the longitudinal axis, and a plurality of key slots each extending through the heat shield body and extending from the central aperture to one of the fuel apertures of the plurality of fuel apertures, each key slot including a first portion arranged in a non-radial direction with respect to the longitudinal axis and extending from one of the fuel apertures.

[0006] The foregoing has outlined rather broadly the technical features of the present disclosure so that those skilled in the art may better understand the detailed description that follows.

Additional features and advantages of the disclosure will be described hereinafter that form the subject of the claims. Those skilled in the art will appreciate that they may readily use the conception and the specific embodiments disclosed as a basis for modifying or designing other structures for carrying out the same purposes of the present disclosure. Those skilled in the art will also realize that such equivalent constructions do not depart from the spirit and scope of the disclosure in its broadest form.

[0007] Also, before undertaking the Detailed Description below, it should be understood that various definitions for certain words and phrases are provided throughout this specification and those of ordinary skill in the art will understand that such definitions apply in many, if not most, instances to prior as well as future uses of such defined words and phrases. While some terms may include a wide variety of embodiments, the appended claims may expressly limit these terms to specific embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Fig. 1 is a perspective view of a gas turbine engine including a combustion section. [0009] Fig. 2 is section view of a fuel injection nozzle for use in the combustion section of Fig. 1

[0010] Fig. 3 is an enlarged section view of a portion of the fuel injection nozzle of Fig. 2 including a tip piece, a swirler member, and a heat shield.

[0011] Fig. 4 is a perspective view of the tip piece of Fig. 3.

[0012] Fig. 5 is a perspective view of the swirler member of Fig. 3.

[0013] Fig. 6 is a perspective view of the heat shield of Fig. 3.

[0014] Fig. 7 is a front view of the heat shield of Fig. 6.

[0015] Fig. 8 is an enlarged front view of one of the fuel openings of the heat shield of Fig. 6.

[0016] Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.

DETAILED DESCRIPTION

[0017] Various technologies that pertain to systems and methods will now be described with reference to the drawings, where like reference numerals represent like elements throughout.

The drawings discussed below, and the various embodiments used to describe the principles of the present disclosure in this patent document are by way of illustration only and should not be construed in any way to limit the scope of the disclosure. Those skilled in the art will understand that the principles of the present disclosure may be implemented in any suitably arranged apparatus. It is to be understood that functionality that is described as being carried out by certain system elements may be performed by multiple elements. Similarly, for instance, an element may be configured to perform functionality that is described as being carried out by multiple elements. The numerous innovative teachings of the present application will be described with reference to exemplary non-limiting embodiments.

[0018] Also, it should be understood that the words or phrases used herein should be construed broadly, unless expressly limited in some examples. For example, the terms“including,” “having,” and“comprising,” as well as derivatives thereof, mean inclusion without limitation.

The singular forms“a”,“an” and“the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. Further, the term“and/or” as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items. The term“or” is inclusive, meaning and/or, unless the context clearly indicates otherwise. The phrases“associated with” and“associated therewith,” as well as derivatives thereof, may mean to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, or the like.

[0019] Also, although the terms "first", "second", "third" and so forth may be used herein to refer to various elements, information, functions, or acts, these elements, information, functions, or acts should not be limited by these terms. Rather these numeral adjectives are used to distinguish different elements, information, functions or acts from each other. For example, a first element, information, function, or act could be termed a second element, information, function, or act, and, similarly, a second element, information, function, or act could be termed a first element, information, function, or act, without departing from the scope of the present disclosure.

[0020] In addition, the term "adjacent to" may mean: that an element is relatively near to but not in contact with a further element; or that the element is in contact with the further portion, unless the context clearly indicates otherwise. Further, the phrase“based on” is intended to mean “based, at least in part, on” unless explicitly stated otherwise. Terms“about” or“substantially” or like terms are intended to cover variations in a value that are within normal industry manufacturing tolerances for that dimension. If no industry standard as available a variation of 20 percent would fall within the meaning of these terms unless otherwise stated.

[0021] Fig. 1 illustrates a gas turbine engine 10 including a compressor section 15, a combustor section 20, and a turbine section 25. A rotor 30 extends along a longitudinal axis 35 the full length of the gas turbine engine 10 and includes a portion that resides in each section of the engine 10. Any compressor section design can be employed with the illustrated compressor section 15 including an inlet 40 and a plurality of rows of stationary blades or guide vanes. In some constructions, some of the guide vanes are movable to enhance operation of the gas turbine engine 10 under varying inlet and power output conditions. The portion of the rotor 30 disposed within the compressor section 15 supports rows of rotating blades that reside between the stationary blades with pairs of stationary blade rows and rotating blade rows cooperating to define compressor stages.

[0022] The turbine section 25 is similar to the compressor section 15 as it includes a number of stages with each stage including a row of stationary blades and a row of rotating blades attached to the rotor 30. In some constructions, the stationary blades may be movable to accommodate different operating conditions. The turbine section 25 also includes an outlet 45 downstream of the last stage of blades.

[0023] The design or arrangement of the compressor section and the turbine section are not critical to combustor section 20 discussed herein. As such, any compressor section 15 and/or turbine section 25 design could be employed.

[0024] The illustrated combustor section 20 is a can-annular design in which multiple separate combustor areas 50 are arranged around the longitudinal axis 35 for the combustion of fuel in the gas turbine engine 10. Each combustor area 50 is substantially the same as the others and includes a liner (not shown) that surrounds a fuel nozzle 60 (shown in Fig. 2). Combustion occurs within the liner with additional compressed air flowing outside of the liner. The additional compressed air mixes with the combustion gases exiting the liner to form a flow of gas that enters the turbine section 25. Of course, other combustor section designs could be employed as desired so long as they employ the fuel nozzle 60 illustrated in Figs. 2-7.

[0025] Turning to Fig. 2, the fuel nozzle 60 is illustrated in section to show the various components and possible flows through the nozzle 60. The illustrated nozzle 60 is a dual fuel nozzle (e.g., oil or natural gas) with optional water injection. The nozzle 60 includes a nozzle body 65 that defines a flange 70, an annular fuel space 75, a central injection space 80 (or central bore), and a nozzle tip 85. The flange 70 facilitates the attachment of the nozzle body 65 to the gas turbine engine 10. The flange 70 also delimits an interior portion 90 of the nozzle body 65 from an exterior portion 95. The exterior portion 95 includes a pipe connection 100 that facilitates the delivery of fuel to the nozzle body 65.

[0026] The central injection space 80 extends along a long axis 105 of the fuel nozzle 60 and provides a passage for the flow of water (liquid or steam). The annular fuel space 75 surrounds the central injection space 80 and provides a passage from the pipe connection 100 to the nozzle tip 85 for the flow of the selected fuel.

[0027] The nozzle tip 85, best illustrated in Figs. 2 and 3 includes a tip piece 110 (sometimes referred to as a tip housing) formed separate from the nozzle body 65 (shown in Fig. 4) that is then attached to the nozzle body 65 using a welding or other similar process. The tip piece 110 includes an outer annular wall 115 and an inner annular wall 120 that cooperate to complete the annular fuel space 75. A plurality of fuel holes 125 are arranged such that each hole 125 extend through the tip piece 110 to direct fuel from the annular fuel space 75 to the exterior 95 of the nozzle body 65. The inner annular wall 120 completes the central injection space 80 and provides a passage in the form of fuel holes 125 from the central injection space 80 to the exterior 95 of the nozzle body 65. The outer surface of the tip piece 110 includes a plurality of standoff members 130 (sometimes referred to as spacers) arranged circumferentially around the long axis of the nozzle body 65. The spacing of the standoff members 130 results in a castellated pattern on the top of the tip piece 110.

[0028] Figs. 2 and 3 illustrate the tip piece 110 attached to the nozzle body 65. A heat shield 135 is positioned on top of the tip piece 110 and a swirler member 140 is attached to the nozzle body 65. The swirler member 140, illustrated in Fig. 5 includes a plurality of windows 145 and a swirler plate 150 that surrounds the heat shield 135 and includes a plurality of apertures 155 arranged to direct a flow of air through the swirler plate 150 and to induce a swirling flow pattern in the air as it passes. Specifically, swirl is induced in a counterclockwise direction when looking in the direction of flow (arrow 160 in Fig. 5) and clockwise when looking into the direction or at a front face of the heat shield 135.

[0029] Figs. 6 and 7 illustrate the heat shield 135 in greater detail. As shown in Fig. 7, the heat shield 135 includes a large central opening 165 that is defined and surrounded by a lip portion 170 that is substantially planar. A frustoconical portion 175 extends from the lip portion 170 to an outer diameter and a cylindrical outer wall 180 extends from the outer diameter in a direction parallel to the longitudinal axis 105 of the nozzle body 65. Each of a plurality of fuel openings 185 extend though the frustoconical portion 175 and are arranged to align with the fuel holes 125 in the tip piece 110. The cylindrical wall 180 is substantially annular and includes a plurality of apertures 190 that extend through the wall 180. As illustrated in Fig. 6, the apertures 190 are oval with other shapes, arrangements or quantities being possible.

[0030] With reference to Fig. 7, a plurality of slots 195 each extend from the central opening 165 to one of the fuel openings 185. The slots 195 are arranged such that there is a one to one relationship between slots 195 and fuel openings 185. In other words, each fuel opening 185 intersects with one and only one slot 195 and each slot 195 extends to only one of the fuel openings 185. Each slot 195 includes a first portion 200 that extends from the central opening 165 across the lip portion 170. The first portion 200 is preferably radial with respect to the longitudinal axis 105 of the fuel nozzle 60 but can be non-radial if desired.

[0031] A second portion 205 of the slot 195 extends from the end of the first portion 200 to one of the fuel openings 185. The second portion 205 of the slot 195 is non-radial and intersects the fuel opening 185 at a point offset from the closest point to the central opening 165. More specifically, each fuel opening 185 can be broken into four distinct quadrants 210a, 210b, 210c, 21 Od separated by a point 215 closest to the central opening 165, a point 220 furthest from the central opening 165 and two points 225 that intersect a circle centered on the longitudinal axis 105 and passing through the center of the fuel opening 185. When looking into the flow at the top surface of the heat shield 135 as shown in Fig. 7, the four quadrants 210a, 210b, 210c, 210d include a first quadrant 210a that extends from the point 220 furthest from the central opening 165 (the 12 o’clock position) to one of the points 225 on the circle (the 3 o’clock position). A second quadrant 210b extends from the 3 o’clock position 225 to the point 215 nearest the central opening 165 (the 6 o’clock position). A third quadrant 210c extends from the 6 o’clock point 215 to the second point 225 that lies on the circle (the 9 o’clock position). A fourth quadrant 21 Od completes the circle and extends from the 9 o’clock position 225 to the 12 o’clock position 220. Using this description, each second portion 205 of the slot 195 ends in the third quadrant 210c of the fuel opening 185. In preferred constructions, the second portion 205 engages the fuel opening 185 between the 7 o’clock position and the 8 o’clock position. This intersection is such that the intersection is about 2-4 mm from a radial line 230 tangent to the point 225 that defines the 9 o’clock position.

[0032] The first portion 200 of the slot 195 is positioned so that the second portion 205 of the slot 195 can intersect the fuel opening 185 as just described and such that the second portion 205 extends at an angle 235 with respect to a radial line 230 of 25 to 30 degrees (plus or minus 20 percent). The placement of the slot 195 assures that the heat shield 135 remains flexible during operation.

[0033] To assemble the fuel nozzle 60, the tip piece 110 is first attached to the nozzle body 65. As noted earlier, it is preferred that the tip piece 110 be permanently welded to the nozzle body 65, but other attachment mechanisms or arrangements are possible. The heat shield 135 is positioned on top of the standoff members 130 to provide flow gaps therebetween. The fuel openings 185 in the heat shield 135 are aligned with the fuel holes 125 of the tip piece 110 and the heat shield 135 is removably affixed using fasteners or other similar means. The swirler member 140 is then attached to the nozzle body 65 using a series of fasteners to complete the assembly of the nozzle 60. The assembled nozzle 60 is then inserted into the combustor section 20 of the gas turbine engine 10 and attached using fasteners that pass through the nozzle body flange 70. The fuel supply, water supply, and any control mechanisms are then attached to complete the assembly.

[0034] In operation, the rotor 30 of the gas turbine engine 10 rotates to draw atmospheric air into the inlet 40 of the compressor section 15. The various stages of the compressor section 15 operate to increase the pressure of the air. The high-pressure air is then delivered to the combustor section 20.

[0035] In the combustor section 20, fuel is delivered to each of the fuel nozzles 60 and flows through the annular fuel space 75 to the tip piece 110. The fuel flows through the fuel holes 125 of the tip piece 110, the fuel openings 185 of the heat shield 135 and is ignited such that a standing flame extends from near the heat shield 135. A portion of the high-pressure air flows through the swirler member 140 and induces a swirl in the area downstream of the heat shield 135. In the illustrated construction, the swirl is in a counterclockwise direction 160 when facing in the direction of the flow. This swirl also has the effect of dragging the standing flames in the same counterclockwise direction 160.

[0036] Some of the high-pressure air passes through the windows 145 of the swirler member 140 and passes through the apertures 190 in the cylindrical outer wall 180 of the heat shield 135.

This air then flows between the standoff members 130 and out the central opening 165 to cool the heat shield 135.

[0037] After combustion, the products of combustion mix with the remaining high-pressure air to produce a flow of high pressure, high temperature gas that enters the turbine section 25 of the gas turbine engine 10. Within the turbine section 25, the gas expands and imparts rotational energy in the form of torque on the rotor 30. The torque is sufficient to drive the compressor section 15 and additional equipment such as an electrical generator.

[0038] The heat produced by the standing flame can cause large thermal gradients within the heat shield 135. The thermal gradients result in differential heating of the heat shield 135 that can lead to distortion, high stress, and residual stress build-ups during cycling operation. The slots 195 are arranged to pass through one of the hotter regions, and more preferably to the counterclockwise side of the hotter region to increase the flexibility of the heat shield 135 in an area of high thermal gradients by adding cooling air that will flow over the hotter region to reduce the thermal gradients. The slots 195 provide room for the heat shield 135 to grow and expand and also provide increased flexibility, thereby allowing the heat shield 135 to move and flex rather than distort and crack.

[0039] Although an exemplary embodiment of the present disclosure has been described in detail, those skilled in the art will understand that various changes, substitutions, variations, and improvements disclosed herein may be made without departing from the spirit and scope of the disclosure in its broadest form.

[0040] None of the description in the present application should be read as implying that any particular element, step, act, or function is an essential element, which must be included in the claim scope: the scope of patented subject matter is defined only by the allowed claims. Moreover, none of these claims are intended to invoke a means plus function claim construction unless the exact words "means for" are followed by a participle.

Claims

CLAIMS What is claimed is:

1. A fuel injection nozzle for a gas turbine comprising:

a nozzle body defining a longitudinal axis and including a plurality of fuel openings arranged annularly around the longitudinal axis; and

a heat shield coupled to the nozzle body, the heat shield including:

a central aperture;

a plurality of fuel apertures arranged annularly around the longitudinal axis; and a plurality of key slots arranged annularly around the longitudinal axis, each key slot extending through the heat shield and extending from the central aperture to one fuel aperture of the plurality of fuel apertures.

2. The fuel injection nozzle of claim 1 , wherein the nozzle body includes a central bore that aligns with the central aperture and is operable to inject a flow of non-fuel fluid.

3. The fuel injection nozzle of claim 1 , wherein the heat shield includes a frustoconical portion and an annular portion centered on and extending parallel to the longitudinal axis.

4. The fuel injection nozzle of claim 3, wherein each of the plurality of fuel apertures extends through the frustoconical portion.

5. The fuel injection nozzle of claim 1 , wherein each key slot extends to one and only one of the plurality of fuel apertures and each fuel aperture receives one and only one key slot.

6. The fuel injection nozzle of claim 1 , wherein each key slot extends from the fuel aperture in a non-radial direction with respect to the longitudinal axis.

7. The fuel injection nozzle of claim 1 , wherein each key slot includes a radial portion that extends from the central aperture and intersects a non-radial portion that extends from the fuel aperture.

8. The fuel injection nozzle of claim 1 , wherein each key slot defines an angle between 20 and 35 degrees with respect to a radial line extending from the intersection of the key slot and the fuel aperture.

9. The fuel injection nozzle of claim 8, wherein the angle is between 25 and 30 degrees.

10. The fuel injection nozzle of claim 1, further comprising a tip housing coupled to the nozzle body and positioned between the nozzle body and the heat shield, the tip housing including a plurality of spaced apart spacers that contact the heat shield to support the heat shield and define a plurality of cooling passages between the plurality of spaced apart spacers.

11. The fuel injection nozzle of claim 1, further comprising a swirler attached to the nozzle body and arranged to produce a swirling fluid flow around the longitudinal axis in a direction downstream of the heat shield.

12. A fuel injection nozzle for a gas turbine comprising:

a heat shield coupled to the nozzle body, the heat shield including:

a central aperture;

a plurality of fuel apertures arranged annularly around the longitudinal axis; and a plurality of key slots, each key slot including a first portion that extends in a non-radial direction with respect to the longitudinal axis from one of the plurality of fuel apertures toward the central aperture and a second portion that extends from the first portion to the central aperture.

13. The fuel injection nozzle of claim 12, wherein the nozzle body includes a central bore that aligns with the central aperture and is operable to inject a flow of non-fuel fluid.

14. The fuel injection nozzle of claim 12, wherein the heat shield includes a frustoconical portion and an annular portion centered on and extending parallel to the longitudinal axis, and wherein each of the plurality of fuel apertures extends through the frustoconical portion.

15. The fuel injection nozzle of claim 12, wherein each key slot extends to one and only one of the plurality of fuel apertures and each fuel aperture receives one and only one key slot.

16. The fuel injection nozzle of claim 12, wherein the second portion of each key slot extends in a radial direction from the central aperture.

17. The fuel injection nozzle of claim 12, wherein the first portion of each key slot defines an angle between 20 and 35 degrees with respect to a radial line extending from the intersection of an end of the key slot and the fuel aperture.

18. The fuel injection nozzle of claim 17, wherein the angle is between 25 and 30 degrees.

19. The fuel injection nozzle of claim 12, further comprising a tip housing coupled to the nozzle body and positioned between the nozzle body and the heat shield, the tip housing including a plurality of spaced apart spacers that contact the heat shield to support the heat shield and define a plurality of cooling passages between the plurality of spaced apart spacers.

20. The fuel injection nozzle of claim 19, wherein the tip housing includes a plurality of fuel openings each positioned in one of the spacers of the plurality of spaced apart spacers.

21. The fuel injection nozzle of claim 12, further comprising a s wirier attached to the nozzle body and arranged to produce a swirling fluid flow around the longitudinal axis in a direction downstream of the heat shield.

22. A heat shield for a gas turbine fuel injection nozzle, the heat shield comprising: a heat shield body including a frustoconical portion, a central aperture centered on a longitudinal axis, and an annular portion centered on and extending parallel to the longitudinal axis;

a plurality of fuel apertures formed in the frustoconical portion and spaced annularly around the longitudinal axis; and

a plurality of key slots each extending through the heat shield body and extending from the central aperture to one of the fuel apertures of the plurality of fuel apertures, each key slot including a first portion arranged in a non-radial direction with respect to the longitudinal axis and extending from one of the fuel apertures.

23. The heat shield of claim 22, wherein the first portion of each key slot defines an angle between 20 and 35 degrees with respect to a radial line extending from the fuel aperture and intersecting an end of the key slot.

24. The heat shield of claim 23, wherein the angle is between 25 and 30 degrees.