TECHNICAL FIELD

[0001] Disclosed embodiments relate generally to a combustor liner in a gas turbine engine, and in particular, cooling rings of a combustor liner in a gas turbine engine.

DESCRIPTION OF THE RELATED ART

[0002] An industrial gas turbine engine typically includes a compressor section, a turbine section, and a mid-frame section disposed therebetween. The compressor section includes multiple stages of compressor rotating blades and stationary vanes and an outlet guide vane assembly aft of the last stage rotating blade and stationary vane. The mid-frame section typically includes a compressor exit diffusor and a combustor. The compressor exit diffusor diffuses the compressed air from the compressor section into a plenum through which the compressed air flows to the combustor which mixes the compressed air with fuel and ignites the mixture and transits the ignited mixture to the turbine section for mechanical power. The turbine section includes multiple stages of turbine rotating blades and stationary vanes.

[0003] The combustor includes a combustor liner that encloses a combustion chamber where the combustion process of the compressed air and fuel mixture occurs. The combustor liner must be designed and manufactured to withstand high temperature and high stress levels. Air cooling is typically required for the combustor liner. An effective cooling of the combustor liner is important for improving the combustor life.

BRIEF SUMMARY

[0004] Briefly described, aspects of the disclosed embodiments relate to a combustor liner in a gas turbine engine and a method for making a combustor liner in a gas turbine engine.

[0005] According to an aspect, a combustor liner in a gas turbine engine is presented. The combustor liner comprises an upstream combustor liner segment. The combustor liner comprises a downstream combustor liner segment attached to the upstream combustor liner segment. Each of the upstream combustor liner segment and the downstream combustor liner segment comprises a forward section extending downstream continuing into a middle section extending upward continuing into an aft section extending downstream. The combustor liner comprises a louver formed as a portion of the aft section of the upstream combustor liner segment. The louver extends downstream beyond the forward section of the downstream combustor liner segment. The combustor liner comprises a plurality of cooling holes arranged at each of the upstream combustor liner segment and the downstream combustor liner segment and circumferentially spaced apart from each other. The plurality of cooling holes are oriented to direct cooling air to impinge the louver to cool the louver with impingement cooling and convective film cooling.

[0006] According to an aspect, a method for cooling a combustor liner of a gas turbine engine is presented. The method comprises arranging an upstream combustor liner segment. The method comprises arranging a downstream combustor liner segment. The method comprises attaching the downstream combustor liner segment to the upstream combustor liner segment. Each of the upstream combustor liner segment and the downstream combustor liner segment comprises a forward section extending downstream continuing into a middle section extending upward continuing into an aft section extending downstream. The method comprises forming a louver as a portion of the aft section of the upstream combustor liner segment extending downstream beyond the forward section of the downstream combustor liner segment. The method comprises arranging a plurality of cooling holes at each of the upstream combustor liner segment and the downstream combustor liner segment and circumferentially spacing apart from each other. The method comprises directing cooling air through the plurality of cooling holes to impinge the louver to cool the louver with impingement cooling and convective film cooling.

[0007] According to an aspect, a combustor liner in a gas turbine engine is presented. The combustor liner comprises an upstream combustor liner segment. The combustor liner comprises a downstream combustor liner segment attached to the upstream combustor liner segment. Each of the upstream combustor liner segment and the downstream combustor liner segment comprises a forward section extending downstream continuing into a middle section extending obliquely upward continuing into a curved section continuing into an aft section extending downstream. The middle section is inclined downstream toward the aft section. The combustor liner comprises a louver formed as a portion of the aft section of the upstream combustor liner segment. The louver extends downstream beyond the forward section of the downstream combustor liner segment. The combustor liner comprises a plurality of cooling holes arranged at each of the upstream combustor liner segment and the downstream combustor liner segment and circumferentially spaced apart from each other. The plurality of cooling holes are oriented to direct cooling air to impinge the louver to cool the louver with impingement cooling and convective film cooling.

[0008] Various aspects and embodiments of the application as described above and hereinafter may not only be used in the combinations explicitly described, but also in other combinations. Modifications will occur to the skilled person upon reading and understanding of the description.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Exemplary embodiments of the application are explained in further detail with respect to the accompanying drawings. In the drawings: [0010] FIG. 1 is a schematic diagram of a gas turbine engine;

[0011] FIG. 2 is a schematic perspective view of a combustor liner of a gas turbine engine according to an embodiment;

[0012] FIG. 3 is a schematic section view of a combustor liner segment according to an embodiment;

[0013] FIG. 4 is a schematic perspective view of a cooling ring of a combustor liner according to an embodiment;

[0014] FIG. 5 is a schematic section view of a cooling ring of a combustor liner shown in FIG. 4; and

[0015] FIGs. 6 to 9 are schematic views of a cooling ring of a combustor liner having cooling holes at a curved section according to various embodiments.

[0016] To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures.

DETAILED DESCRIPTION

[0017] A detailed description related to aspects of disclosed embodiments is described hereafter with respect to the accompanying figures.

[0018] For illustration purpose, the term “axial” or “axially” refers to a direction along a longitudinal axis of a gas turbine engine, the term “radial” or “radially” refers to a direction perpendicular to the longitudinal axis of the gas turbine engine, the term “downstream” or “aft” refers to a direction along a flow direction, the term “upstream” or “forward” refers to a direction against the flow direction.

[0019] FIG. 1 illustrates a schematic diagram of a gas turbine engine 10. As illustrated in FIG. 1, the gas turbine engine 10 includes a plurality of components along a longitudinal axis 18. The plurality of components includes a compressor section 100, a turbine section 400 located downstream of the compressor section 100 with respect to a flow direction 12, and a mid-frame section 200 that is located therebetween. A rotor 14 longitudinally connects the compressor section 100, the mid-frame section 200 and the turbine section 400 and is circumferentially enclosed thereby. The mid-frame section 200 includes a compressor exit diffuser 220 and a combustor 300.

[0020] In operation of the gas turbine engine 10, the compressor section 100 inducts air via an inlet duct (not shown). The air is compressed and accelerated in the compressor section 100 while passing through multiple stages of compressor rotating blades (not shown) and compressor stationary vanes (not shown), as indicated by the flow direction 12. The compressed air passes through the compressor section 100 and enters the compressor exit diffuser 220 which passes the compressed air to a plenum 240 through which the compressed air flows to the combustor 300. The compressed air is mixed with fuel in the combustor 300. The mixture is ignited and burned in the combustor 300 to form a combustion gas. The combustion gas enters the turbine section 400, as indicated by the flow direction 12. The combustion gas is expanded in the turbine section 400 while passing through multiple stages of turbine stationary vanes (not shown) and turbine rotating blades (not shown) to generate mechanical power which drives the rotor 14 rotating along the longitudinal axis 18. The rotor 14 is linked to an electric generator or other devices (not shown) to convert the mechanical power to electrical power or work, such as to drive a gas compressor. The expanded gas constitutes exhaust gas and exits the gas turbine engine 10.

[0021] The combustor 300 includes a combustor liner 310. A portion of the combustor liner 310 is illustrated in FIG. 2. The combustor liner 310 extends from an upstream end 312 to a downstream end 314 along the flow direction 12. The combustor liner 310 circumferentially encloses an interior cavity that defines a combustor chamber 340 in which the compressed air from the compressor section 100 is mixed with fuel and ignited and burned and exit to the turbine section 400 at the downstream end 314, as indicated by the flow direction 12. The combustor liner 310 may have any suitable circumferential cross-section shapes. In one non-limiting embodiment as indicated in FIG. 2, the combustor liner 310 has a generally circular circumferential cross-section shape. The combustor liner 310 may have other circumferential cross-section shapes, such as oval or rectangular, etc. The combustor liner 310 may transition between different circumferential cross-section shapes, such as, for example, from a generally circular circumferential cross- section shape to a generally oval circumferential cross-section shape.

[0022] The combustor liner 310 includes a plurality of combustor liner segments 320 arranged axially along the flow direction 12. The plurality of combustor liner segments 320 include an upstream combustor liner segment 320 and a downstream combustor liner segment 320.

[0023] FIG. 3 is a schematic section view of a portion of one of the combustor liner segments 320. As shown in FIG. 2 and 3, each combustor liner segment 320 includes a forward section 321 extending generally downstream. The forward section 321 continues into a middle section 322 extends generally upward. The middle section 322 continues into an aft section 323 extending generally downstream. The middle section 322 is inclined downstream toward the aft section 323. An angle 326 between the middle section 322 and the aft section 323 is oblique. For example, the angle 326 between the middle section 322 and the aft section 323 may be 30 degrees, 45 degrees, or 60 degrees, or any other oblique angles, etc. As shown in FIG.2, at the upstream stages, the forward section 321 and the aft section 323 of the combustor liner segments 320 generally extend axially. At the downstream stages, the forward section 321 and the aft section 323 of the combustor liner segments 320 may generally extend toward a centerline of the combustor chamber 340.

[0024] Adjacent combustor liner segments 320 are attached to each other at respective adjacent end regions. As shown in FIG. 2, the forward section 321 of a downstream combustor liner segment 320 is attached to the aft section 323 of an upstream combustor liner segment 320. The combustor liner segments 320 may be attached by any industrial known methods, such as by any type of welding, for example, fusion welding, laser welding, resistance welding, etc. A louver 324 is formed as a portion of the aft section 323 of the upstream combustor liner segment 320. The louver 324 extends downstream beyond the forward section 321 of the downstream combustor liner segment 320.

[0025] Each combustor liner segment 320 includes a plurality of cooling holes 332. The cooling holes 332 perforate the combustor liner segment 320. The cooling holes 332 are arranged circumferentially around the combustor liner segment 320 and spaced apart from each other. The cooling holes 332 may be arranged circumferentially in line forming a row. The cooling holes 332 may also be arranged circumferentially staged to each other.

[0026] A plurality of cooling rings 330 are formed at the end regions between adjacent combustor liner segments 320. FIG. 4 is a schematic perspective view of a cooling ring 330 according to an embodiment. FIG. 5 is a schematic section view of the cooling ring 330 shown in FIG. 4 illustrating the cooling effects.

[0027] In operation of the gas turbine engine 10, cooling air 331 is fed from the compressor section 100 and flows over outer surface of the combustor liner 310 facing away from the combustion chamber 340. The cooling air 331 enters the combustor chamber 340 through the cooling holes 332 to provide a convective film cooling to inner surface of the combustor liner 310 facing the combustion chamber 340. The cooling air 331 also provides convective film cooling to the louver 324.

[0028] The combustor liner 310 endures high stress levels during operation of the gas turbine engine 10. Efficient heat extraction at the cooling ring 330 of the combustor liner 310 is important to relieve the thermal fight between the louver 324 of the cooling ring 330 and the combustor liner 310. Improvement of cooling to the combustor liner 310 is important to improve the life of the combustor liner 310.

[0029] In non-limiting embodiments as shown in FIGs. 2 to 5, the disclosed cooling holes 332 are located and oriented to direct the cooling air 331 to impinge the louver 324 to provide both impingement cooling and convective film cooling to the louver 324. As shown in FIGs. 4 and 5, the cooling holes 332 are located at the middle section 322 of the combustor liner segment 320. The middle section 322 extends obliquely upward and is inclined downstream toward the aft section 323. The cooling holes 332 perforate the middle section 322 with an angle with respect to the middle section 322. In one non limiting embodiment as shown in Figs. 4 and 5, the cooling holes 332 may be perpendicular to the middle section 322. It is understood that the cooling holes 322 may be oriented at the middle section 322 with any angles to direct the cooling air 332 to impinge the louver 324. The cooling air 331 enters the cooling holes 332 and impinges the louver 322 to provide impingement cooling to the louver 324 in addition to the convective film cooling to the louver 324.

[0030] The size of the cooling holes 332 and the number of cooling holes 332 are designed to efficiently improve the cooling effect to the louver 324. For example, the diameter of the cooling holes 332 maybe 1.5 mm, or 1.8 mm, or 2 mm, etc. The number of cooling holes 332 maybe 30, or 36, or 46, etc. The larger the diameter of the cooling holes 332, the less the number of the cooling holes 332. [0031] The louver 324 is designed to efficiently improve the cooling effect to the louver 324. For example, a length 327 of the louver 324 is selected to provide efficient cooling effect to the louver 324. A radial distance 328 between the louver 324 of the upstream combustor liner segment 320 and the aft section 323 of the downstream combustor liner segment 320 is also selected to provide efficient cooling effect to the louver 324. For example, the radial distance 328 between the louver 324 of the upstream combustor liner segment 320 and the aft section 323 of the downstream combustor liner segment 320 maybe 1.5 mm, or 2 mm, or 2.5 mm, etc.

[0032] In non-limiting embodiments as shown in FIGs. 2 to 5, the combustor liner segment 320 may include a curved section 325 disposed between the middle section 322 and the aft section 323. The curved section 325 continues from the middle section 322 and continues into the aft section 323. The curved section 325 may include any shapes, such as an arc, a semi-circle, etc. The curved section 325 further enhances the recirculation zone between the combustor liner segment 320 and the louver 324 to further improve the cooling effects to the louver 322. A size of the curved section 325 is selected to provide efficient cooling effects to the louver 324. For example, a radius of the curved section 325 maybe 1.8 mm, 2 mm, or 2.2 mm, etc.

[0033] FIG. 6 is a schematic section view of a cooling ring 330 according to an embodiment. As shown in FIG. 6, the cooling hole 332 is located at the curved section 325 of the combustor liner segment 320. The cooling hole 332 perforates the curved section 325 with an angle with respect to the curved section 325. In one non-limiting embodiment as shown in FIG. 6, the cooling hole 332 is not perpendicular to the curved section 325. It is understood that the cooling hole 332 may be oriented in the curved section 325 with any angles to direct the cooling air 331 to impinge the louver 324.

[0034] Orientation of the louver 324 is also selected to provide efficient cooling effect to the louver 324. In non-limiting embodiments as shown in FIGs. 5 and 6, the louver 324 is a straight portion of the axial section 323. In non-limiting embodiments as shown in FIGs. 7 and 8, the louver 324 is a bent portion of the aft section 323 bending towards the downstream combustor liner segment 320. A bent louver 324 may direct the cooling air 331 towards inner surfaces of the downstream combustor liner segments 320 facing to the combustor chamber 340 to improve cooling of the downstream combustor liner segments 320. A bent location at the louver 324 and an angle bending towards the downstream combustor liner segment 320 are designed to provide efficient cooling effect to the louver 324 and the combustor liner segments 320.

[0035] The disclosed embodiments may be combined to meet design criteria as needed. For example, in one non-limiting embodiment as shown in FIG. 7, the cooling ring 330 has the cooling hole 332 that is located at the middle section 322 of the combustor liner segment 320. In one non-limiting embodiment as shown in FIG. 8, the cooling ring 330 has the cooling hole 332 that is located at the curved section 323. It is also understood that the cooling hole 332 may be located at the aft section 323 of the combustor liner segment 320. The cooling hole 332 is oriented to direct the cooling air 331 to impinge the louver 324.

[0036] FIG. 9 is a schematic view of a cooling ring 330 according to an embodiment. As shown in FIG. 9, the cooling ring 330 has two rows of cooling holes 332. Each row of the cooling holes 332 are arranged circumferentially spaced apart from each other. The two rows of cooling holes 332 may be arranged circumferentially in line with each other or staggered with each other. The cooling holes 332 are oriented to direct the cooling air 331 to impinge the louver 324 to cool the louver 324 with impingement cooling and convective film cooling. In one non-limiting embodiment as shown in FIG. 9, the two rows of the cooling holes 332 are both located at the middle section 322. It is understood that the two rows of cooling holes 332 may be both located at the curved section 325, or both located at the aft section 323, or each located at different sections of the combustor liner segment 320.

[0037] The disclosed combustor liner 310 includes cooling ring 330 having features to improve cooling effectiveness to the combustor liner 310. The improved cooling effectiveness of the cooling ring 330 allows using comparable less strength materials for the combustor liner 310 while withstanding the high stress levels during operation of the gas turbine engine 10. The less strength materials may include thin sheet metal. Thickness of the sheet metal may be selected to meet the design requirements. For example, the thickness of the sheet metal maybe 6 mm or thicker. The thin sheet metal may include, for example, Hatelloy® X alloy, etc. The proposed combustor liner 310 avoids a need for high strength thick forged cooling ring to sufficiently cool the combustor liner 310 during operation of the gas turbine engine 10. Materials of a forged cooling ring is typically more expensive than thin sheet metal.

[0038] According to an aspect, the disclosed cooling ring 330 includes cooling holes 332 that are circumferentially arranged at the combustor liner segment 320. The cooling holes 332 are oriented to direct the cooling air 331 to impinge the louver 324 to cool the louver 324 with both impingement cooling and convective film cooling. The disclosed cooling ring 330 improves the cooling effects to the louver 324 and thus the combustor liner 310 with minimal modification to the flow field of the combustor 300. The disclosed combustor liner 310 thus significantly improves the life of the combustor liner 310.

[0039] According to an aspect, the disclosed combustor liner 310 may use cost- effective thin sheet metal design that avoids a need for expensive thick forged cooling ring design. The sheet metal combustor liner segments 320 may be welded to form the combustor liner 310. The disclosed combustor liner 310 is cost-effective and able to withstand the high stress levels caused by discrepancy in thermal expansion between the louver 324 and the combustor liner 310. The disclosed combustor liner 310 may avoid a need for additional cooling rings or a need to lengthen the louver 324 in order to provide sufficient cooling to the combustor liner 310.

[0040] Although various embodiments that incorporate disclosed concepts have been shown and described in detail herein, those skilled in the art can readily devise many other varied embodiments that still incorporate these disclosed concepts. Disclosed embodiments are not limited to the specific details of construction and the arrangement of components set forth in the description or illustrated in the drawings. Disclosed concepts may be implemented by other implementations, and of being practiced or of being carried out in various ways, which now would become apparent to one skilled in the art. 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. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless specified or limited otherwise, the terms “mounted,” “connected,” “supported,” and “coupled” and variations thereof are used broadly and encompass direct and indirect mountings, connections, supports, and couplings. Further, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings.

Reference List:

10: Gas Turbine Engine

12: Flow Direction

14: Rotor

18 : Longitudinal Axis

100: Compressor Section

200: Mid-Frame Section

220: Compressor Exit Diffusor

240: Compressed Air Plenum

300: Combustor

310: Combustor Liner

312: Upstream End of the Combustor Liner

314: Downstream End of the Combustor Liner

320: Combustor Liner Segment

321: Forward Section

322: Middle Section

323: Aft Section

324: Louver

325: Curved Section

326: Angle between the Middle Section and the Aft Section 327: Louver Length

328: Distance between Louver and Downstream Combustor Liner

330: Cooling Ring

331: Cooling Air

332: Cooling Hole

340: Combustor Chamber

400: Turbine Section