Cooling method and structure of a gas turbine blade

Abstract

A method for cooling a turbine guide vane is provided. The turbine includes a blade profile, an outer cover located at an outer radial end of the blade profile, and an inner cover. The blade profile includes a plurality of air channels extending along the radial direction of the turbine, the air channels comprising a first air channel and a second air channel. Cooling air is caused to flow in the first air channel to cool the first air channel and then cool either the outer cover or the inner cover. Cooling air is caused to flow in the second air channel to cool the second air channel and then cool either the outer cover or the inner cover.

Description

[TECHNICAL FIELD]

[0001] The present disclosure relates to a cooling method of a guide vane of a gas turbine and also relates to a cooling structure of a guide vane of a gas turbine. [State of the art]

[0002] A gas turbine guide vane and a gas turbine rotor blade are exposed to high-temperature combustion gas. Thus, the guide vane and rotor blade are cooled by cooling air. For example, Japanese Patent Application Laid-Open No. 2013-019348 (JP '348) describes the cooling of a static turbine blade. Fig. 3 of JP '348 describes that cooling gas RG first flows into an outer cover 12, then flows downward into a blade body 11 and is discharged through a plurality of openings 223 to cool the blade body 11, then flows downward toward an inner cover 13, flows into the inner cover 13 to cool the inner cover 13. In other words, Fig. 3 of JP '348 first cools the outer cover 12, then cools the blade body 11 using the cooling gas RG that has cooled the outer cover 12, then cools the inner cover 13 using the cooling gas RG that has cooled the blade body 11. [Citation list][Patent documents]

[0003] [Patent Document 1] Japanese Laid-Open Patent Application, First Publication No. 2013-019348 [Overview of the invention][Technical problem]

[0004] Recently, gas turbine inlet temperatures have been rising, and therefore, it is desirable to further facilitate the cooling of the inlet guide vane. One approach to addressing the above is to supply cooling air with higher pressure and lower temperature (compared with conventional technology) to the inlet guide vane. According to the inventor's study, in a case where the higher pressure and lower temperature cooling air is used to cool the inlet guide vane, even after the cooling air has been used to cool a blade profile or shroud edge, there is a possibility that the cooling air can be reused to cool other elements or components of the inlet guide vane. However, in conventional technology, the efficiency of using the cooling air is limited.

[0005] It is desirable to provide a cooling method or structure of a gas turbine guide vane that enables better efficiency in the use of cooling air. [Solution to the problem]

[0006] According to a first aspect of the present disclosure, a method is provided for cooling a guide vane of a turbine, the turbine having a blade profile, a cover arranged at one end of the blade profile, the end being a radial end along a radial direction of the turbine, the cover comprising an outer cover arranged at a radially outer end of the blade profile in the radial direction of the turbine, and an inner cover arranged at a radially inner end of the blade profile in the radial direction of the turbine, the blade profile comprising a plurality of air channels extending along the radial direction of the turbine, the air channels comprising a first air channel and a second air channel. The method comprises the steps: (i) causing cooling air to flow in the first air duct to cool the first air duct, then cooling the outer cover or the inner cover using the cooling air that has flowed in the first air duct; and (ii) causing a cooling air to flow in the second air duct to cool the second air duct, then cooling the other of the outer cover or the inner cover using the cooling air that has flowed in the second air duct.

[0007] With the above-described feature, the cooling air used to cool the blade profile can be used to cool other components of the stationary blade, such as the outer cover or the inner cover, without discharging the cooling air into a hot gas passage. Thus, it becomes possible to improve the efficiency of using cooling air. In addition, the outer cover and the inner cover can be cooled using cooling air with a relatively lower temperature immediately after cooling the blade profile. Furthermore, the cooling air used to cool the first air passage can be used to cool the outer cover or the inner cover, and the cooling air used to cool the other air passage can be used to cool another one of the outer cover and the inner cover. Thus, it becomes possible to improve the efficiency of using cooling air.

[0008] According to a second aspect of the present disclosure, a turbine guide vane is provided, comprising a blade profile; and a cover arranged at one end of the blade profile, the end being a radial end along a radial direction of the turbine, the cover comprising an outer cover arranged at a radially outer end of the blade profile in the radial direction of the turbine, and an inner cover arranged at a radially inner end of the blade profile in the radial direction of the turbine. The blade profile comprises a plurality of air channels extending along the radial direction of the turbine, the air channels comprising a first air channel and a second air channel. The blade profile comprises an air inlet configured to introduce cooling air from outside the guide vane into the first air channel and the second air channel.The first air duct communicates with the outer cover or the inner cover to supply the cooling air introduced into the first air duct to the outer cover or the inner cover to cool the outer cover or the inner cover. The second air duct communicates with the other of the outer cover or the inner cover to supply the cooling air introduced into the second air duct to the other of the outer cover or the inner cover to cool the other of the outer cover or the inner cover.

[0009] With the above-described feature, the cooling air used to cool the blade profile can be used to cool other components of the stationary blade, such as the outer cover or the inner cover, without discharging the cooling air into a hot gas passage. Thus, it becomes possible to improve the efficiency of using cooling air. In addition, the cooling air is first introduced into the air ducts to cool the blade profile, and the outer cover and the inner cover can be cooled using cooling air with a relatively lower temperature immediately after cooling the blade profile. Furthermore, the cooling air used to cool the first air duct can be used to cool the outer cover or the inner cover, and the cooling air used to cool the other air duct can be used to cool another of the outer cover or the inner cover.This makes it possible to improve the efficiency of using cooling air. [Brief description of the drawings] Fig. 1 is a schematic sectional view of a gas turbine in one embodiment according to the present disclosure. Fig. 2 is a perspective view of a guide vane in a first embodiment. Fig. 3 is a sectional view along the line III-III of Fig. 2. Fig. 4 is a partial enlarged view of the guide vane. Fig. 5 is a perspective view of a part of a guide vane in the first embodiment. Fig. 6 is a perspective view of a portion of a guide vane in another embodiment. Fig. 7 is a flowchart illustrating a cooling method of the stationary vane of the first embodiment. Fig. 8 is a flowchart illustrating a cooling method of the guide vane of the second embodiment. Fig. 9 schematically illustrates cooling steps of the second embodiment. Fig. 10 is a flowchart illustrating a cooling method of the guide vane of the third embodiment. Fig. 11 is a schematic sectional view of a guide vane according to the fourth embodiment. Fig. 12A and Fig. 12B are each a schematic sectional view of a guide vane according to the fifth embodiment. Fig. 13A and Fig. 13B are each a schematic sectional view of a guide vane according to the sixth embodiment. [Description of the embodiments]

[0010] A preferred embodiment of the present disclosure will be described in detail below with reference to the drawings. Fig. 1 is a schematic sectional view of a gas turbine in one embodiment according to the present disclosure. As shown in Fig. 1, a gas turbine 10 of this embodiment includes a turbine 20 driven by combustion gas generated by a combustor 30. The turbine 20 has a rotor shaft 24, a turbine rotor 26 rotating about an axis Ar, a turbine casing 22 covering the turbine rotor 26, and a plurality of vane stages 28.

[0011] Fig. 2 schematically illustrates a guide vane of a gas turbine according to an embodiment of the present disclosure. Fig. 2 is a perspective view of a guide vane in a first embodiment. Fig. 3 is a sectional view along the line III-III of Fig. 2. Fig. 4 is a partial enlarged view of the guide vane. As shown in Fig. As shown in Fig. 2, a guide vane 50 includes a guide vane body (blade profile) 51 extending in a radial direction of a gas turbine, an inner cover 60 disposed on the radially inner side of the guide vane body 51, and an outer cover 70 disposed on the radially outer side of the guide vane body 51. The guide vane body 51 is disposed in a combustion gas flow passage (hot gas passage) through which the combustion gas flows. Generally, an annular combustion gas flow passage is defined by the inner cover 60 on the radially inner side thereof and by the outer cover 70 on the radially outer side thereof. The inner cover 60 and the outer cover 70 are plate-shaped members that define a part of the combustion gas flow passage.

[0012] As in Fig. As shown in Figure 2, one end of the vane body 51 on the upstream side has a leading edge 52, and one end of the vane body 51 on the downstream side has a trailing edge 53. Among the surfaces of the vane body 51, a convex surface is a suction-side surface 54 (negative pressure surface), and a concave surface is a pressure-side surface 55 (positive pressure surface). For convenience, in the following descriptions, the pressure side (positive pressure surface side) of the vane body 51 and the suction side (negative pressure surface side) of the vane body 51 are referred to as a pressure side and a suction side, respectively.

[0013] The inner cover 60 and the outer cover 70 have basically the same structure. Therefore, the outer cover 70 will be mainly described below.

[0014] As in Fig. 2 and Fig. 3, the outer cover 70 is a plate-shaped cover member including a cover base 72, a cover edge 74 disposed at a periphery of the cover base 72, and a peripheral wall 76 extending along the cover edge 74 and projecting from the cover base 72 toward the radially outer side of the gas turbine.

[0015] The outer cover 70 has a front end surface that is an end surface on the upstream side, a rear end surface that is an end surface on the downstream side, a pressure-side end surface that is an end surface on the pressure side, and a suction-side end surface that is an end surface on the suction side. The outer cover 70 has a gas path surface 78 that faces the radially inner side and faces the hot gas passage. The front end surface and the rear end surface are substantially parallel to each other. The pressure-side end surface and the suction-side end surface are substantially parallel to each other. Thus, the outer cover 70 has a substantially parallelogram shape when viewed from the radial direction, as shown in Fig. 3 shown.

[0016] The cover edge 74 is a brim- or rim-shaped structure that protrudes from the cover body 72. The cover edge 74 includes a front cover edge 74 L , which is arranged on the upstream side of the outer cover 70, a rear cover edge 74 T , which is arranged on the downstream side of the outer cover 70, a suction-side cover edge 74 N , which is arranged on the suction side of the outer cover 70, and a pressure-side cover edge 74 P which is arranged on the pressure side of the outer cover 70. For example, as shown by Fig. 3, the front cover edge 74 L , the rear cover edge 74 T , the suction-side cover edge 74 N and the pressure-side cover edge 74 Parranged on a circumference of the cover base body 72 to completely surround the cover base body 72.

[0017] The front cover edge 74 L includes a front cover edge passage 75 L in it. The rear cover edge 74 T includes a rear cover edge passage 75 T in it. The suction-side cover edge 74 N includes a suction-side cover edge passage 75 N in it. The pressure-side cover edge 74 P includes a pressure-side cover edge passage 75 P in it.

[0018] In this embodiment, the front cover edge passage 75 L with the suction-side cover edge passage 75 N at one end of it and is connected to the pressure-side cover edge passage 75 Pat the other end of it. The rear cover edge passage 75 T stands with the suction-side cover edge passage 75 N at one end of it and is connected to the pressure-side cover edge passage 75 P at the other end of it. As in Fig. 2, Fig. 3 and Fig. 4, the front cover edge passage 75 L a cover edge passage inlet 171. The rear cover edge passage 75 T has a cover edge passage outlet 172. A portion of the cooling air passing through the cover edge passage inlet 171 into the front cover edge passage 75 L flows through the suction-side cover edge passage 75 N and the pressure-side cover edge passage 75 P , then flows through the rear cover edge passage 75 Tand then flows out of the cover edge passage outlet 172. As in Fig. 3, the cover edge passages include 75 L , 75 T , 75 P , 75 N Turbulators 175. The turbulator 175 may be a rib disposed on an inner surface of the cover edge passages. To improve cooling of the cover edge, the turbulator 175 may be disposed on a bottom surface of the passage defining a radially inner side of the passage. Here, the bottom surface of the passage may extend substantially parallel to the radially inner wall 81. Furthermore, the turbulator 175 may be disposed on a side surface of the passage defining an outer lateral side of the passage.

[0019] In the present embodiment, the cover edge passage inlet 171 for the front cover edge passage 75 Lprovided and the cover edge passage outlet 172 is for the rear cover edge passage 75 T However, the structure of the guide vane is not limited to this embodiment. The shroud edge passage inlet 171 may be provided for another shroud edge passage, such as the suction-side shroud edge passage 75. N , the pressure-side cover edge passage 75 P or the rear cover edge passage 75 T . The cover edge passage outlet 172 may be provided for another cover edge passage, such as the suction side cover edge passage 75 N , the pressure-side cover edge passage 75 P or the front cover edge passage 75 L Alternatively, a plurality of cover edge passage inlets 171 for one or more of the cover edge passages 75 L , 75T , 75 N , 75 P be provided. In addition, a plurality of cover edge passage outlets 172 for one or more of the cover edge passages 75 L , 75 T , 75 N , 75 P be provided.

[0020] The cover body 72 includes a radially inner wall 81 and a radially outer wall 82 opposite the radially inner wall 81. The cover body 72 includes a cavity S therein between the radially inner wall 81 and the radially outer wall 82. The radially inner surface of the inner wall 81 forms the gas path surface 78 of the outer cover 70. The radially inner wall 81 forms a part of the cover body 72. The radially inner wall 81 may extend continuously outward to form a part of the cover edge 74. Fig. Figure 2 describes as an embodiment that the radially inner wall 81 extends continuously outwardly to form a part of the rear cover edge 74 T The cover main body 72 includes a baffle plate 73 that divides the space S of the outer cover 70 into an outer region on the radially outer side and an inner region (cavity), which is a region on the radially inner side. The outer region is connected to the cover edge passage outlet 172, so that part of the cooling air from the rear cover edge passage 75 T flows into the outer region. The inner region is defined between the baffle plate 73 and the radially inner wall 81 of the outer cover 70.

[0021] A plurality of air holes 79 are provided in the baffle plate 73 to extend through the baffle plate 73 in the radial direction. A portion of the cooling air present in the outer region flows through the air holes 79 of the baffle plate 73 into the inner cavity.The cooling air is ejected from the air holes 79 toward a radially outer surface of the radially inner wall 81 for impingement cooling of the radially outer surface of the radially inner wall 81, and then discharged through the radially outer wall 82 toward the outer side of the outer wall 82. For example, the cooling air is ejected from the air holes 79 toward a radially outer surface of the radially inner wall 81 for impingement cooling of the radially outer surface of the radially inner wall 81, and then discharged through a passage connecting the inner region (cavity) of the cavity (S) and an outer space located on the opposite side of the radially outer wall 82 with respect to the cavity (S). Such a passage may be insulated from the outer region of the cavity (S). More specifically, in this embodiment, the cooling air is discharged through a hole of an exhaust duct 83.The outlet conduit 83 is provided to penetrate through the radially outer wall 82 and the baffle plate 73 to connect the inner region and the outer space. (blade profile)

[0022] The guide vane body 51 comprises a plurality of air channels 141, 142, 143. More specifically, the interior of the guide vane body 51 is separated by radially extending partition walls 51 Pdivided into the plurality of air channels 141, 142, 143. A plurality of inserts 151, 152, 153 are inserted into the respective air channels 141, 142, 143. The plurality of inserts 151, 152, 153, which include respective radially extending inner air channels 161, 162, 163, extend in the radial direction from the outer cover 70 through the guide vane body 51 to the inner cover 60. Each of the inserts 151, 152, 153 is formed continuously from the outer cover 70 through the guide vane body 51 to the inner cover 60. Each of the inner air channels 161, 162, 163 has an air inlet 58 open to the inside of an intake manifold 56.

[0023] Each of the inserts 151, 152, 153 has a plurality of openings (through holes) 59 that communicate with the respective inner air channels 161, 162, 163. A portion of the cooling air supplied to the inner air channels 161, 162, 163 of the inserts 151, 152, 153 is expelled from the plurality of openings 59 toward an inner surface of the vane body 51 for impingement cooling of the inner surface of the blade profile 51. The plurality of air channels 141, 142, 143 have respective outer air channels defined between the inserts 151, 152, 153 and the inner surface of the vane body 51. The part of the cooling air which is expelled through the openings 59 is guided through the outer air channels in the radially outward direction, in the radially inward direction or in both the radially outward direction and the radially inward direction through the outer air channels and flows through them.As an example shows . Fig. 3 the outer air channel 57 between the side surface of the insert 151 and the inner surface of the front end part of the guide vane body 51.

[0024] The intake manifold 56 and the exhaust duct 83 are connected to a forced air cooling system in which cooling air taken from inside a combustor casing is cooled by an external cooler (not shown) and then compressed by an external compressor (not shown). The compressed air is used for cooling and then returned to the interior of the combustor casing. In the above description, the air cooling system is applied to the present embodiment. However, the present vane is not limited to such an embodiment. The present disclosure may be applied to a different type of cooling system. For example, the intake manifold 56 and the exhaust duct 83 may be connected to a closed-cycle steam cooling system or a closed-cycle air cooling system.The compressed air used for cooling is supplied to the intake manifold and first provided directly to the air inlet 58 without passing through the cover base 72 or the cover edge 74. In other words, the cooling air is first used to cool the blade profile 51 before being used to cool the cover base 72 or the cover edge 74.

[0025] In the present embodiment, the air duct 141 is a front-end air duct positioned at an upstream end of the vane body 51. For example, in the insert 151, which is a front-end insert, a portion of the cooling air supplied to the inner air duct 161 through the air inlet 58 is expelled through the openings 59 toward the inner surface of the front end portion of the blade profile 51 and then guided to flow outward in the radial direction through the outer air duct 57. The outer air duct 57, which is a space between the insert 151 and the inner surface of the front end portion of the vane body 51, communicates with the shroud edge passage inlet 171 of the front shroud edge passage 75. LThe part of the cooling air discharged toward the inner surface of the leading end portion of the blade profile 51 flows into the cover edge passage inlet 171 of the leading cover edge passage 75. L through the outer air duct 57, which is connected to the cover edge passage inlet 171.

[0026] Fig. 5 is a perspective view of a part of a guide vane in the first embodiment. In the present embodiment, the air duct 142 is an intermediate air duct positioned on a downstream side of the front-end air duct 141 and also positioned between the front-end air duct 141 and a rear-end air duct 143 (described below). For example, in the insert 152, which is an intermediate insert, a part of the cooling air supplied to the inner air duct 162 through the air inlet 58 is discharged through the openings 59 toward the inner surface of the center part of the blade profile 51 and then guided to flow inward in the radial direction through its own outer air duct toward the inner cover 60, then, as shown by Fig. 5, into the cover edge passage inlet 181 of the inner cover 60 (which is located on a rear cover edge 64 Tis arranged). The cooling air then flows through the cover edge passage 65 of the inner cover 60 to cool the cover edge 64 of the inner cover 60, and then flows into the cover main body 62 of the inner cover 60 through the cover edge passage outlet 182 of the inner cover 60 (which is arranged on a front cover edge 64 L is arranged). In a similar manner to the outer cover 70, the cooling air is expelled from the air holes of the baffle plate 63 to cool the radially outer wall of the inner cover 60, which has a gas path surface facing the radially outer side and facing the hot gas path.

[0027] In the present embodiment, a part of the cooling air discharged from the front-end inner air passage 161 toward the inner surface of the front end portion of the blade profile 51 is guided to flow outward in the radial direction through the outer air passage 57 toward the outer cover 70. Furthermore, a part of the cooling air discharged from the intermediate inner air passage 162 toward the inner surface of the intermediate portion of the blade profile 51 is guided to flow inward in the radial direction through the outer air passage 57 toward the inner cover 60. However, the structure of the stationary vane is not limited to this embodiment.A portion of the cooling air discharged from the front-end inner air duct 161 toward the inner surface of the front end portion of the blade profile 51 may be guided to flow inward in the radial direction through the outer air duct 57 toward the inner cover 60. Furthermore, a portion of the cooling air discharged from the intermediate inner air duct 162 toward the inner surface of the intermediate portion of the blade profile 51 may be guided to flow outward in the radial direction through the outer air duct 57 toward the outer cover 70. Such a modification will be further described below as another embodiment.

[0028] In some embodiments of this disclosure, as by Fig. 2, the air duct 143 is a rear-end air duct positioned at a downstream end of the vane body 51. The rear-end air duct 142 also includes a blade profile cooling structure 154 on a downstream side of the insert 153. The blade profile cooling structure 154 includes a passage in which a plurality of pin fins 164 are arranged. For example, in the insert 153, which is a rear-end insert, a part of the cooling air supplied to the inner air duct (rear-end inner air duct) 163 through the air inlet 58 is discharged through the openings 59 toward the inner surface of a rear end portion of the blade profile 51, then guided to flow to the blade profile cooling structure 154. A portion of the cooling air flows through the passage with the pin ribs 164 and is then expelled to the hot gas passage at the trailing edge 53 of the blade profile 51.

[0029] Fig. 6 is a perspective view of a portion of a guide vane in another embodiment. As in Fig. 6, in this embodiment, the cover edge passage inlet 181 of the inner cover 60 is at the front cover edge 64 L In addition, the cover edge through-outlet 182 of the inner cover 60 is arranged at the rear cover edge 64 T arranged. In addition, in this embodiment, the cover edge passage inlet 171 of the outer cover 70 is arranged at the rear cover edge 74 T In addition, the cover edge passage outlet 172 of the outer cover 70 is arranged on the front cover edge 74 LIn this embodiment, in the insert 151, which is the front end insert, a part of the cooling air supplied to the inner air duct 161 through the air inlet 58 is discharged through the openings 59 toward the inner surface of the front end part of the blade profile 51 and then guided to flow inward in the radial direction through the outer air duct 57 toward the inner cover 60, then, as shown in Fig. 6, into the cover edge passage inlet 181 of the inner cover 60 (which is located at the front cover edge 64 L is arranged). The cooling air then flows through the cover edge passage 65 of the inner cover 60 to cool the cover edge 64 of the inner cover 60, and then flows into the cover main body 62 of the inner cover 60 through the cover edge passage outlet 182 of the inner cover 60 (which is arranged at the rear cover edge 64 Tis arranged). Furthermore, in this embodiment, in the insert 152, which is an intermediate insert, a part of the cooling air supplied to the inner air duct 162 through the air inlet 58 is discharged through the openings 59 toward the inner surface of the center part of the blade profile 51 and then guided to flow outward in the radial direction through the outer air duct toward the outer cover 70, then flows into the cover edge passage inlet 171 of the outer cover 70 (which is provided at the rear cover edge 74 T is arranged). The cooling air then flows through the cover edge passage 75 of the outer cover 70 to cool the cover edge 74 of the outer cover 70, and then flows into the cover main body 72 of the outer cover 70 through the cover edge passage outlet 172 of the outer cover 70 (which is located at the front cover edge 74 L is arranged). (COOLING PROCESS)

[0030] Next, a cooling method of a guide vane of the first embodiment will be described. Fig. 7 is a flowchart illustrating a cooling method of the guide vane of the first embodiment. As shown by Fig. 7, in a step S102, a portion of the cooling air is supplied to the front-end air duct 141 to cool the front-end air duct 141. The cooling air is discharged from the front-end inner air duct 161 through the openings 59 of the insert 151 toward the inner surface of the front end portion of the blade profile 51, and is guided in either the radially outward direction or the radially inward direction through the outer air duct 57 toward the outer cover 70 or the inner cover 60 to cool the outer cover 70 or the inner cover 60.

[0031] In a step S104, a portion of the cooling air is supplied to the intermediate air duct 142 to cool the intermediate air duct 142. The cooling air is expelled from the intermediate inner air duct 162 through the openings 59 of the insert 152 toward the inner surface of the intermediate part of the blade profile 51, and is guided in the other of the radially outward direction or the radially inward direction through the outer air duct 57 toward the outer cover 70 or the inner cover 60 to cool the other of the outer cover 70 or the inner cover 60.

[0032] Next, a cooling method of a guide vane of the second embodiment will be described. Fig. 8 is a flowchart illustrating a cooling method of the guide vane of the second embodiment.

[0033] This method will be described using the air duct 141 and the outer cover 70 as examples. Fig. Figure 9 schematically illustrates cooling steps of the second embodiment. As shown by Fig. 8 and Fig. As shown in Figure 9(a), in a step S202, a portion of the cooling air is supplied through the air inlet 58 to the inner air passage 161 of the insert 151. The cooling air is then expelled through the openings 59 toward the inner surface of the leading end portion of the blade profile 51 to cool the blade profile 51, and then flows outward in the radial direction through the outer air passage 57. In some of these embodiments, the portion of the cooling air supplied to the inner air passage 161 may be introduced from the forced air cooling system.

[0034] As through Fig. As shown in Figure 9(b), in a step S204, the cooling air is supplied to the cover edge passage 75 through the cover edge passage inlet 171. The cooling air flows along and through the cover edge passage 75 to cool the cover edge 75.

[0035] As through Fig. 9(c), in a step S206, the cooling air flows into the outer region of the cover main body 72 and is discharged through the air holes 79 toward the radially outer surface of the radially inner wall 81 for impingement cooling of the radially outer surface of the radially inner plate 81 to cool the cover main body 72.

[0036] Next, a cooling method of a guide vane of a third embodiment will be described. Fig. 10 is a flowchart illustrating a cooling method of the guide vane of the third embodiment. As shown by Fig. As shown in Figure 10, in a step S302, a portion of the cooling air is supplied through the air inlet to the inner air duct of the insert in at least one of the air ducts. The cooling air is then expelled through the openings toward the inner surface of the leading end portion of the blade profile to cool the blade profile and then flows radially outward through the outer air duct. In some of these embodiments, the portion of the cooling air supplied to the inner air duct may be introduced by the forced air cooling system.

[0037] In a step S304, the cooling air is supplied to the outer region of the cover main body and is expelled through the air holes toward the radially outer surface of the radially inner wall for impingement cooling of the radially outer surface of the radially inner wall to cool the cover main body.

[0038] In step S306, the cooling air is supplied to the cover edge passage through the cover edge passage inlet. The cooling air flows along and through the cover edge passage to cool the cover edge. In some embodiments, the cooling air may be recirculated to the forced air cooling system through the cover edge passage outlet.

[0039] Next, the fourth embodiment of the present application will be described below. Fig. 11 is a schematic sectional view of a guide vane according to the fourth embodiment. As shown by Fig. 11, in the fourth embodiment, a plurality of the blade profiles 51 (two blade profiles in this embodiment) are separated from the cover edge passages 75 L , 75 T , 75 N , 75 P Unlike the first embodiment ( Fig. 3) are two cover edge passage inlets 171 for the front cover edge passage 75 L provided.

[0040] The respective outer air channels, which are a space between the insert 151 and the inner surface of the front end part of the two blade profiles 51, are connected to the respective cover edge passage inlets 171 of the front cover edge passage 75 L through the respective air passages provided in an outer end of the respective outer air channels of the respective blade profiles 51. The cooling air flows through the respective cover edge passage inlets 171 into the front cover edge passage 75. L and flows through the suction-side cover edge passage 75 N or the pressure-side cover edge passages 75 P, then flows through the cover edge passage outlet 172 into the outer region of the cover body 72.

[0041] In the above embodiments, the vane body (blade profile) includes three air channels 141, 142, 143. However, the number of air channels included in the vane body (blade profile) is not limited to three. The vane body (blade profile) may include a different number of air channels, such as two, four, five, or more. In such a modified embodiment, each air channel may be connected to the outer cover or the inner cover.

[0042] For example, the fifth embodiment of the present application will be described below. Fig. 12A and Fig. 12B are each a schematic sectional view of a guide vane according to the fifth embodiment. As shown by Fig. 12A and Fig. 12B, the vane body (blade profile) in the fifth embodiment includes air passages 191, 192, 193, 194, and 195 arranged in this order from an upstream end to a downstream end thereof with respect to the hot gas flow in the turbine.

[0043] The air channels 191, 192, 193, 194 and 195 each include an insert and an inner air channel (not shown). As indicated by Fig. 12A, the first air duct 191 and the second air duct 192 are connected to the cover edge passage inlet 171 of the outer cover 70, which is provided on the front cover edge 74 L In addition, as shown by Fig. 12B, the third air duct 193 and the fourth air duct 194 with the cover edge passage inlet 181 of the inner cover 60, which is located at the rear cover edge 64 T is arranged in connection.

[0044] In the present embodiment, part of the cooling air introduced into the first air duct 191 flows in the first air duct 191 and is discharged from a first inner air duct through the openings 59 of a first insert toward the inner surface of the front end part of the blade profile 51, then guided to flow outward in the radial direction through the outer air duct 57 toward the outer cover 70. Similarly, part of the cooling air discharged from a second inner air duct of the second air duct 192 through the openings 59 of a second insert toward the inner surface of the intermediate part of the blade profile 51 is guided to flow outward in the radial direction through its own outer air duct 57 toward the outer cover 70. Then, the cooling air is guided into the cover edge passage inlet 171 of the outer cover 70.

[0045] In the present embodiment, a portion of the cooling air discharged from a third inner air passage of the third air passage 193 through the openings 59 of a third insert toward the inner surface of the intermediate part of the blade profile 51 is guided to flow radially inward through the dedicated outer air passage 57 toward the inner cover 60. Furthermore, a portion of the cooling air discharged from a fourth inner air passage of the fourth air passage 194 through the openings 59 of a fourth insert toward the inner surface of the intermediate part of the blade profile 51 is guided to flow radially inward through the dedicated outer air passage 57 toward the inner cover 60.

[0046] Then, the cooling air is guided into the cover edge passage inlet 181 of the inner cover 60.

[0047] The fifth air duct 195 is a rear-end air duct positioned at a downstream end of the vane body 51. As described above, in the fifth air duct 195, a portion of the cooling air supplied to a fifth internal air duct through the air inlet 58 is discharged through the openings 59 toward the inner surface of a rear end portion of the airfoil 51, then guided to flow to the airfoil cooling structure 154. A portion of the cooling air flows through the passage with the pin fins 164 and is then discharged to the hot gas passage at the trailing edge 53 of the airfoil 51.

[0048] The structure of the guide vane is not limited to this embodiment. As an alternative embodiment, the cover edge passage inlet 171 of the outer cover 70 may be provided at the rear cover edge 74. Tbe arranged and the cover edge passage outlet 172 of the outer cover 70 can be arranged on the front cover edge 74 L In addition, the cover edge passage inlet 181 of the inner cover 60 can be arranged on the front cover edge 64 L be arranged and the cover edge passage outlet 182 of the inner cover 60 is at the rear cover edge 64 T In this embodiment, the first air duct 191 and the second air duct 192 are connected to the cover edge passage inlet 181 of the inner cover 60, which is arranged on the front cover edge 64 L In addition, the third air duct 193 and the fourth air duct 194 are connected to the cover edge passage inlet 171 of the outer cover 70, which is arranged on the rear cover edge 74 T is arranged in connection.

[0049] Next, the sixth embodiment of the present application will be described below.

[0050] Fig. 13A and Fig. 13B are each a schematic sectional view of a guide vane according to the sixth embodiment. In this embodiment, the outer cover 70 includes two cover edge passage inlets (a front cover edge passage inlet 171 L and a rear cover edge passage inlet 171 T ), and two cover edge passage outlets (one pressure-side cover edge passage outlet 172 P and a suction-side cover edge passage outlet 172 N ). The front cover edge passage inlet 171 L is for the front cover edge 74 L provided. The rear cover edge passage inlet 171 T is for the rear cover edge 74 Tprovided. The pressure-side cover edge passage outlet 172 P is for the pressure-side cover edge 74 P provided. The suction-side cover edge passage outlet 172 N is for the suction-side cover edge 74 N provided. The air channels 191, 192, 193, 194 and 195 each include an insert and an inner air channel (not shown).

[0051] In this embodiment, the inner cover 60 includes two cover edge through inlets (a front cover edge through inlet 181 L and a rear cover edge passage inlet 181 T ) and two cover edge passage outlets (one pressure-side cover edge passage outlet 182 P and a suction-side cover edge passage outlet 182 N ). The front cover edge passage inlet 181 L is for the front cover edge 64L provided. The rear cover edge passage inlet 181 T is for the rear cover edge 64 T provided. The pressure-side cover edge passage outlet 182 P is for the pressure-side cover edge 64 P provided. The suction-side cover edge passage outlet 182 N is for the suction-side cover edge 64 N provided.

[0052] As through Fig. 13A, the first air duct 191 is connected to the cover edge passage inlet 171 L the outer cover 70, which is on the front cover edge 74 L In addition, the fourth air duct 194 is connected to the cover edge passage inlet 171 T the outer cover 70, which is on the rear cover edge 74 T arranged in connection. As shown by Fig. 13B, the second air duct 192 is connected to the cover edge passage inlet 181 L the inner cover 60, which is on the front cover edge 64 L The third air duct 193 is connected to the cover edge passage inlet 181 T the inner cover 60, which is on the rear cover edge 64 T is arranged in connection.

[0053] In this embodiment, for example, a part of the cooling air supplied to the first air duct 191 is discharged from a first inner air duct through the openings 59 of a first insert toward the inner surface of the front end part of the blade profile 51 and then guided to flow outward in the radial direction through its own outer air duct toward the outer cover 70, then flows as shown by Fig. 13A, into the front cover edge passage inlet 171 L. The cooling air then flows along the front cover edge passage 75 L . Then the cooling air flows along the pressure-side cover edge passage 75 P , then flows out of the pressure-side cover edge passage outlet 172 P out, also flows along the suction-side cover edge passage 75 N , then flows out of the pressure-side cover edge passage outlet 172 N out. In this embodiment, for example, a part of the cooling air supplied to the fourth air duct 194 is discharged from a fourth inner air duct through the openings 59 of a fourth insert toward the inner surface of the center end portion of the blade profile 51 and then guided to flow outward in the radial direction through its own outer air duct toward the outer cover 70, then flows as shown by Fig. 13A, into the rear cover edge passage inlet 171T . The cooling air then flows along the rear cover edge passage 75 T . Then the cooling air flows along the pressure-side cover edge passage 75 P , then flows out of the pressure-side cover edge passage outlet 172 P out, also flows along the suction-side cover edge passage 75 N , then flows out of the pressure-side cover edge passage outlet 172 N out of here.

[0054] In this embodiment, for example, a part of the cooling air supplied to the second air duct 192 is discharged from a second inner air duct through the openings 59 of a second insert toward the inner surface of the center part of the blade profile 51 and then guided to flow inward in the radial direction through its own outer air duct toward the inner cover 60, then flows as shown by Fig. 13B, into the front cover edge passage inlet 181 L . The cooling air then flows along the front cover edge passage 65 L . Then the cooling air flows along the pressure-side cover edge passage 65 P , then flows out of the pressure-side cover edge passage outlet 182 P out, also flows along the suction-side cover edge passage 65 N , then flows out of the pressure-side cover edge passage outlet 182 N out. In this embodiment, for example, a part of the cooling air supplied to the third air duct 193 is discharged from a third inner air duct through the openings 59 of a third insert toward the inner surface of the center end part of the blade profile 51 and then guided to flow inward in the radial direction through its own outer air duct toward the inner cover 60, then flows as shown by Fig. 13B, into the rear cover edge passage inlet 181 T . The cooling air then flows along the rear cover edge passage 65 T . Then the cooling air flows along the pressure-side cover edge passage 65 P , then flows out of the pressure-side cover edge passage outlet 182 P out, also flows along the suction-side cover edge passage 65 N , then flows out of the pressure-side cover edge passage outlet 182 N out of here.

[0055] The fifth air duct 195 is a rear-end air duct positioned at a downstream end of the vane body 51. As described above, in the fifth air duct 195, a portion of the cooling air supplied to a fifth internal air duct through the air inlet 58 is discharged through the openings 59 toward the inner surface of a rear end portion of the airfoil 51, then guided to flow to the airfoil cooling structure 154. A portion of the cooling air flows through the passage with the pin fins 164 and is then discharged to the hot gas passage at the trailing edge 53 of the airfoil 51.

[0056] The structure of the guide vane is not limited to this embodiment. As an alternative embodiment, the first air duct 191 may be connected to the cover edge passage inlet 181. L the inner cover 60, which is on the front cover edge 64 LIn addition, the fourth air duct 194 can be connected to the cover edge passage inlet 181 T the inner cover 60, which is on the rear cover edge 64 T In addition, the second air duct 192 can be connected to the cover edge passage inlet 171 L the outer cover 70, which is on the front cover edge 74 L The third air duct 193 is connected to the cover edge passage inlet 171 T the outer cover 70, which is on the rear cover edge 74 T is arranged in connection.

[0057] The present disclosure is not limited to the embodiment described above and may be implemented in various forms. Although a specific form of embodiment has been described above and illustrated in the accompanying drawings for clarity of understanding, the above description is given by way of example and not as limiting the scope of the invention, which is defined by the appended claims. The scope of the invention is to be determined by the appended claims. Various modifications obvious to one of ordinary skill in the art could be made without departing from the scope of the invention. The appended claims cover such modifications. [List of reference symbols] 10 gas turbines 20 turbines 22 Turbine housing 24 Rotor shaft 26 Turbine rotor Ar axis 30 combustion chamber 50 guide vanes 51 Guide vane body (blade profile) 51 P Partition walls 52 leading edge 53 trailing edge 54 suction-side surface 55 print-side surface 56 intake manifold 57 outer air duct 58 Air intake 59 openings 141, 142, 143 Air duct 151, 152, 153 Use 161, 162, 163 inner air duct 191, 192, 193, 194, 195 air duct 154 Blade profile cooling structure 164 pin ribs 60 inner cover 70 outer cover 62, 72 cover body 63, 73 baffle plate 64, 74 cover edge 65, 75 cover edge passage S cavity 171 Cover edge passage inlet 172 Cover edge passage outlet 175 Turbulator 76 Perimeter wall 78 Gas path surface 79 air holes 81 radial inner wall 82 radial outer wall 83 Outlet line 181 Cover edge passage inlet 182 Cover edge passage outlet QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 2013-019348 [0002, 0003]

Claims

[1] Guide vane for a turbine, comprising: a blade profile; and a cover arranged at one end of the blade profile, the end being a radial end along a radial direction of the turbine, the cover comprising an outer cover arranged at a radially outer end of the blade profile in the radial direction of the turbine and an inner cover arranged at a radially inner end of the blade profile in the radial direction of the turbine, wherein the blade profile comprises a plurality of air channels extending along the radial direction of the turbine, the air channels comprising a first air channel and a second air channel, the blade profile comprises an air inlet which is intended to introduce cooling air from outside the guide vane into the first air duct and the second air duct, the first air duct is connected to the outer cover or the inner cover to supply the cooling air introduced into the first air duct to the outer cover or the inner cover to cool the outer cover or the inner cover, and the second air duct communicates with the other of the outer cover or the inner cover to supply the cooling air introduced into the second air duct to the other of the outer cover or the inner cover to cool the other of the outer cover or the inner cover. [2] A guide vane for a turbine according to claim 1, wherein the first air passage is a leading-end air passage positioned at an upstream end of the blade profile with respect to a hot gas flow in the turbine, and wherein the second air passage is an air passage positioned at a downstream side of the leading-end air passage. [3] A guide vane for a turbine according to claim 2, wherein the first air passage communicates with the outer cover so that the outer cover is cooled using the cooling air that has flowed in the first air passage, and the second air passage communicates with the inner cover so that the inner cover is cooled using the cooling air that has flowed in the second air passage. [4] The turbine vane of claim 3, wherein the outer cover comprises an outer cover base body and an outer cover edge disposed at a periphery of the outer cover base body to surround the outer cover base body, the outer cover edge including an outer cover edge passage therein, the inner cover comprises an inner cover base body and an inner cover edge disposed at a periphery of the inner cover base body to surround the inner cover base body, the inner cover edge comprising an inner cover edge passage therein, the first air duct is connected to the outer cover edge passage and the second air duct is connected to the inner cover edge passage. [5] The turbine guide vane according to claim 4, wherein the outer shroud edge includes an outer shroud edge passage inlet disposed at a front end portion of the outer shroud edge, and the first air duct communicates with the outer shroud edge passage through the outer shroud edge passage inlet, and the inner shroud edge includes an inner shroud edge passage inlet disposed at a rear end portion of the inner shroud edge, and the second air duct communicates with the inner shroud edge passage through the inner shroud edge passage inlet. [6] The turbine guide vane according to claim 4, wherein the outer shroud edge includes an outer shroud edge passage inlet disposed at a front end portion of the outer shroud edge, and the first air duct communicates with the outer shroud edge passage through the outer shroud edge passage inlet, and the inner shroud edge includes an inner shroud edge passage inlet disposed at a front end portion of the inner shroud edge, and the second air duct communicates with the inner shroud edge passage through the inner shroud edge passage inlet. [7] The turbine guide vane according to claim 2, wherein the blade profile further comprises a rear-end air duct positioned at a downstream end of the blade profile with respect to the hot gas flow in the turbine, the rear-end air duct extending along the radial direction of the turbine and having an outlet arranged at a downstream end thereof, the outlet being opened to a hot gas passage of the turbine so that cooling air flows in the rear-end air duct to cool the rear-end air duct and is then discharged through the outlet to the hot gas passage of the turbine. [8] The turbine guide vane according to claim 1, wherein the air inlet is arranged to receive the cooling air taken from an interior of a combustor casing and compressed by an external compressor, and the outer cover and the inner cover each comprise an exhaust passage arranged to discharge the cooling air into the interior of the combustor casing. [9] The turbine guide vane according to claim 8, wherein the air inlet is arranged to introduce the cooling air from the interior of the combustor casing into the first air passage and the second air passage without passing through the outer cover or the inner cover. [10] A method for cooling a guide vane of a turbine, the turbine comprising a blade profile, a cover arranged at one end of the blade profile, the end being a radial end along a radial direction of the turbine, the cover comprising an outer cover arranged at a radially outer end of the blade profile in the radial direction of the turbine, and an inner cover arranged at a radially inner end of the blade profile in the radial direction of the turbine, the blade profile comprising a plurality of air channels extending along the radial direction of the turbine, the air channels comprising a first air channel and a second air channel, the method comprising the following steps: Causing cooling air to flow in the first air duct to cool the first air duct, then cooling the outer cover or the inner cover using the cooling air that has flowed in the first air duct; and Causing cooling air to flow in the second air duct to cool the second air duct, then cooling the other of the outer cover or the inner cover using the cooling air that has flowed in the second air duct. [11] A method of cooling the guide vane of the turbine according to claim 10, wherein the first air duct is a leading-end air duct positioned at an upstream end of the blade profile with respect to a hot gas flow in the turbine, and wherein the second air duct is an air duct positioned at a downstream side of the leading-end air duct. [12] A method for cooling the guide vane of the turbine according to claim 11, wherein the outer cover is cooled using the cooling air that has flowed in the first air passage, and the inner cover is cooled using the cooling air that has flowed in the second air passage. [13] A method for cooling the turbine vane according to claim 12, wherein the outer cover comprises an outer cover base body and an outer cover edge disposed at a periphery of the outer cover base body to surround the outer cover base body, the outer cover edge including an outer cover edge passage therein, the inner cover comprises an inner cover base body and an inner cover edge disposed at a periphery of the inner cover base body to surround the inner cover base body, the inner cover edge comprising an inner cover edge passage therein, the cooling air that has flowed in the first air duct is passed through a front end portion of the outer cover edge and introduced into the outer cover edge passage to cool the outer cover edge, and the cooling air that has flowed in the second air duct is guided through a rear end portion of the inner cover edge and introduced into the inner cover edge passage to cool the inner cover edge. [14] A method for cooling the turbine vane according to claim 12, wherein the outer cover comprises an outer cover base body and an outer cover edge disposed at a periphery of the outer cover base body to surround the outer cover base body, the outer cover edge including an outer cover edge passage therein, the inner cover comprises an inner cover base body and an inner cover edge disposed at a periphery of the inner cover base body to surround the inner cover base body, the inner cover edge comprising an inner cover edge passage therein, the cooling air that has flowed in the first air duct is passed through a front end portion of the outer cover edge and introduced into the outer cover edge passage to cool the outer cover edge, and the cooling air that has flowed in the second air duct is guided through a front end portion of the inner cover edge and introduced into the inner cover edge passage to cool the inner cover edge. [15] A method for cooling the guide vane of the turbine according to claim 11, wherein the blade profile further comprises a trailing end air duct positioned at a downstream end of the blade profile with respect to the hot gas flow in the turbine, the trailing end air duct extending along the radial direction of the turbine, the method further comprising: Causing cooling air to flow in the rear-end air duct to cool the rear-end air duct, then discharging the cooling air that has flowed in the rear-end air duct through an outlet disposed at a downstream end of the rear-end air duct to a hot gas passage of the turbine. [16] A method for cooling the turbine vane according to claim 10, further comprising: Introducing the cooling air from outside the guide vane into the first air duct and the second air duct without passing through the outer cover or the inner cover. [17] A method for cooling the turbine vane according to claim 10, further comprising: Introducing the cooling air, which is taken from the interior of a combustion chamber housing and compressed by an external compressor, into the first air duct and the second air duct; and Discharge of cooling air into the interior of the combustion chamber casing from the outer cover and the inner cover.

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