JP5320177B2 - Gas turbine combustor - Google Patents

Description

  The present invention relates to a gas turbine combustor having an improved cooling structure for cooling a combustion cylinder with a part of compressed air from a compressor.

  In recent years, in gas turbine engines, the combustion gas temperature at the turbine inlet tends to be set higher in order to improve thermal efficiency. However, as the flame temperature increases, the amount of NOx generated increases, so the amount of NOx generated is reduced. In order to reduce this, it is necessary to increase the amount of combustion air to suppress the rise in flame temperature. When the amount of combustion air is increased, the amount of air used as cooling air for the combustion cylinder out of the compressed air from the compressor is reduced, so the cooling structure that effectively cools the combustion cylinder with the small amount of cooling air Is desired.

  Conventionally, impingement cooling, convection cooling, film cooling, and the like are known as cooling structures for the combustion cylinder. For example, a gas turbine combustor employing all these three cooling methods has also been proposed (Patent Document 1). The cooling structure of this combustor has a double wall structure in which the combustion cylinder is composed of an inner wall and an outer wall, and the impingement cooling is performed on the inner wall with compressed air introduced into the inner space of the double wall from the impingement cooling hole of the outer wall. The compressed air is cooled by causing the compressed air to flow in the inner space of the double wall while flowing the compressed air toward the upstream side in the flow direction of the combustion gas. The aim is to increase the convective heat transfer efficiency by air and to cool the inner wall effectively by convection cooling.

Japanese Patent No. 3590666

  In Patent Document 1, a film cooling hole is further provided in the vicinity of the downstream end of the inner wall of the combustion cylinder, and a part of the compressed air flowing in the inner space of the double wall toward the upstream side of the combustion gas is passed through the film cooling hole. Then, it is introduced inside the inner wall in a folded form, and flows toward the downstream side of the combustion gas to cool the inner surface of the inner wall with a film. However, in this cooling structure, only a small portion of the compressed air in the double wall is used for film cooling, so that the cooling effect of the combustion cylinder is insufficient.

  It is an object of the present invention to provide a gas turbine combustor having an improved cooling structure so that the combustion cylinder can be effectively cooled with high cooling efficiency by effectively using compressed air for cooling with an inexpensive structure. To do.

  In order to achieve the above object, a gas turbine combustor according to the present invention has a double wall structure in which a part of a combustion cylinder forming a combustion chamber is composed of an outer wall and an inner wall, and an impingement is provided upstream of the double wall structure. A cooling region and a convection cooling region downstream thereof are set, and at least an impingement cooling hole for introducing compressed air from a compressor toward the inner wall is formed on the outer wall of the impingement cooling region. A turbulent flow generating means for disturbing the compressed air in the double wall is provided on the outer peripheral surface of the inner wall, and a space in the double wall is opened in the downstream direction at the downstream end of the convection cooling region. A discharge port for discharging the entire amount of compressed air in the heavy wall as film cooling air is provided. Here, the “upstream part” refers to an upstream part along the flow direction of the combustion gas in the combustion chamber inside the combustion cylinder.

  According to this gas turbine combustor, the compressed air introduced into the double wall from the impingement cooling hole formed in the outer wall of the impingement cooling region provided in the upstream portion of the double wall structure collides with the inner wall, and the inner wall The impingement cools down. When the compressed air after impingement cooling flows in the convection cooling region on the downstream side of the impingement cooling region, turbulent flow is generated in the compressed air by the turbulent flow generating means provided on the outer peripheral surface of the inner wall. The heat transfer from the inner wall to the compressed air is promoted by the turbulent flow, and the inner wall is effectively cooled by the convection cooling by the compressed air. The compressed air in the double wall is further discharged into the combustion chamber as film cooling air from an outlet provided at the downstream end of the convection cooling region. As the film cooling air flows from the impingement cooling region toward the convection cooling region, both the flow rate and the flow velocity increase due to the inflow from the impingement cooling hole, so that the compressed air is injected from the outlet at a high flow velocity. . Thus, all the compressed air in the double wall flows in layers along the inner surface of the inner wall at high speed, so that the inner wall is effectively film cooled. In this way, in this gas turbine combustor, after impingement cooling and convection cooling of the inner wall with compressed air for cooling, all of the compressed air is injected from the discharge port to cool the inner wall with a film. The combustion cylinder can be cooled with high cooling efficiency by effectively using the compressed air.

  In addition, since the combustion cylinder is simply provided with impingement cooling holes on the outer wall and turbulent flow generating means such as ribs on the outer peripheral surface of the inner wall, the structure is simple and the manufacturing cost can be kept low.

  In the present invention, it is preferable that an impingement cooling hole is formed at least in an upstream portion of the outer wall in the convection cooling region. According to this configuration, since the inner wall can be impingement cooled in addition to the convection cooling in the upstream portion of the convection cooling region, the cooling effect is increased. In addition, the compressed air introduced from the impingement cooling hole acts to stir the compressed air flowing in the double wall, so that the convection cooling effect is further promoted.

  In the present invention, a nozzle unit for supplying fuel to the combustion chamber is attached to the head of the combustion cylinder, and the double wall structure is formed in an upstream portion including the head in the combustion cylinder. Is preferred. According to this configuration, the upstream portion of the combustion cylinder is likely to become high temperature due to the combustion of fuel injected from the head nozzle unit into the combustion chamber, but this upstream portion is effectively cooled by impingement cooling and convection cooling. The

  Thus, in the form in which the double wall structure is formed in the upstream part including the head part in the combustion cylinder, the combustion cylinder has a cylindrical part connected to the downstream side of the head part, and the head It is preferable that the impingement cooling region is formed in the upstream portion of the portion and the cylindrical portion. According to this configuration, in the upstream portion of the combustion cylinder, the impingement cooling region having a cooling efficiency superior to that of the convection cooling is provided in the head portion that is likely to be a high temperature and the upstream portion of the cylindrical portion, so that the combustion cylinder Can be effectively cooled.

  In the present invention, the turbulent flow generation means may be an annular rib concentric with the combustion cylinder. According to this configuration, the annular rib concentric with the combustion cylinder can be easily formed by machining as well as being etched, so that the inner wall of the combustion cylinder can be manufactured at low cost.

  According to the gas turbine combustor of the present invention, by providing the impingement cooling region in the upstream portion of the double wall structure, the upstream portion can be effectively cooled by impingement cooling with excellent cooling efficiency. In addition, in the convection cooling region on the downstream side of the impingement cooling region, the flow rate of the compressed air increases as the flow rate of the compressed air increases due to the inflow from the impingement cooling hole. Since the turbulent flow is generated by the surface turbulent flow generating means, heat transfer is promoted and effective convection cooling is performed. In addition, all of the high-speed compressed air that has flowed through the convection cooling region in the double wall is injected into the combustion chamber as film cooling air from the outlet opening at the downstream end of the convection cooling region. The film can be cooled. Moreover, since the combustion cylinder has a simple structure in which the impingement cooling holes are provided on the outer wall and the turbulent flow generating means is provided on the outer peripheral surface of the inner wall, the manufacturing cost can be kept low.

It is a schematic structure figure showing gas turbine equipment to which a gas turbine combustor concerning a 1st embodiment of the present invention is applied. It is a longitudinal cross-sectional view which shows a gas turbine combustor same as the above. It is an expanded longitudinal cross-sectional view which shows the principal part of the combustion cylinder in a gas turbine combustor same as the above. It is the IV-IV sectional view taken on the line of FIG. It is the VV sectional view taken on the line of FIG. It is a perspective view which shows the turbulent flow production | generation means in the gas turbine combustor of 2nd Embodiment of this invention. It is a perspective view which shows the turbulent flow production | generation means in the gas turbine combustor of 3rd Embodiment of this invention. It is a top view which shows the turbulent flow production | generation means in the gas turbine combustor of 4th Embodiment of this invention. (A), (b) is a top view which shows the turbulent flow production | generation means in the gas turbine combustor of 5th Embodiment of this invention, respectively. It is a top view which shows the turbulent flow production | generation means in the gas turbine combustor of 6th Embodiment of this invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic configuration diagram of a gas turbine facility in which the gas turbine combustor according to the first embodiment of the present invention is used. In the figure, a gas turbine GT includes a compressor 1, a combustor 2, and a turbine 3 as main components, and a fuel supply device 4 and a fuel control device 8 are connected to the combustor 2. . Compressed air A supplied from the compressor 1 and fuel F supplied from the fuel supply device 4 via the fuel control device 8 are combusted in the combustor 2, and high-temperature and high-pressure combustion gas G generated thereby is converted into a turbine. 3 to drive the turbine 3. The compressor 1 is driven by a turbine 3 via a rotating shaft 9, and this turbine 3 also drives a load such as a generator 11 via a speed reducer 10. The combustor 2 includes a can type and an annular type. In this embodiment, a can type is used. The present invention can also be applied to an annular type.

  FIG. 2 shows a longitudinal sectional view of the combustor 2, which is a backflow can type in which compressed air A and combustion gas G introduced into the combustor 2 flow in opposite directions in the combustor 2. A substantially cylindrical combustion cylinder 12 is accommodated in a cylindrical housing H, and a combustion chamber 13 is formed inside the combustion cylinder 12. A plurality of (for example, six) combustors 2 are arranged on a cylinder concentric with the axis of the rotating shaft 9 of FIG. The housing H is obtained by connecting a housing top H2 to the head of the housing main body H1 with a bolt 14, and an end cover 18 is fixed to the head on the distal end side of the housing top H2 with a bolt 19.

  The combustion cylinder 12 has a double wall structure in the upstream portion along the flow direction of the combustion gas G due to the outer wall 20 and the inner wall 21. That is, the combustion cylinder 12 has a head portion 12a to which a nozzle unit (burner unit) 28 is attached via an outer duct 28a, and a cylindrical portion 12b connected to the downstream side thereof. Correspondingly, the outer wall 20 has an outer head part 20a and an outer cylindrical part 20b, and the inner wall 21 arranged concentrically with the outer wall 20 is only the inner head part 21a and the upstream part of the combustion cylinder 12. And a short inner cylindrical portion 21b.

  An annular support member 25 projecting radially outward is provided at an upstream portion of the outer cylindrical portion 20b of the outer wall 20, and the radially outer end portion of the support member 25 is formed on the head of the housing body H1. They are connected by bolts 22. As a result, the outer wall 20 of the combustion cylinder 12 is supported by the housing H via the support member 25. The support member 25 is provided with a plurality of air passage holes arranged in the circumferential direction. The outer wall 20 supports the outer duct 28 a of the nozzle unit 28 at the upstream end, and the outer duct 28 a supports the inner wall 21. An annular air passage 23 that guides the compressed air A from the compressor 1 to the head 12a of the combustion cylinder 12, that is, the upstream side, is formed between the cylindrical portion 12b of the combustion cylinder 12 and the housing main body H1 that covers the cylinder portion 12b. Has been. An air introduction chamber 24 is formed inside the end cover 18 in the housing H.

  The nozzle unit 28 attached to the head portion 12a of the combustion cylinder 12 includes a partial premixing type pilot nozzle 29 that directly injects the fuel F into the combustion chamber 13, and the fuel F so as to surround the outer periphery of the pilot nozzle 29. And a premixed main nozzle 30 for jetting a premixed gas M generated by mixing the compressed air A into the combustion chamber 13.

  The upstream end of the L-shaped premixing passage 31 of the main nozzle 30 opens outward in the radial direction, and a plurality of main fuel nozzles 32 are located on the radially outer side of the opened annular air intake port 31a. The nozzles 30 are arranged at equal intervals in the circumferential direction. A plurality of main fuel injection holes 32a are formed in a portion of the main fuel nozzle 32 facing the air intake port 31a. The base end of the main fuel nozzle 32 is connected to a main fuel introduction port 33 provided in the end cover 18. A plurality of swirlers 34 are arranged in the air intake port 31 a in a direction along the axis C of the combustion cylinder 12 (axial direction P). The fuel F supplied from the main fuel injection hole 32a is introduced into the premixing passage 31 along with a part of the compressed air A introduced into the air introduction chamber 24 from the air passage 23 while a swirling force is applied by the swirler 34. After being premixed in the premixing passage 31, the premixed gas M is ejected from the annular premixing outlet 38 into the combustion chamber 13.

  Fuel F is supplied from the fuel supply device 4 of FIG. 1 through the fuel control device 8 to the pilot fuel introduction port 39 and the main fuel introduction port 33 that supply the fuel F to the pilot nozzle 29.

  In the vicinity of the downstream end of the inner cylindrical portion 21 b in the outer cylindrical portion 20 b of FIG. 2, one or a plurality of spark plugs 40 are arranged with the tip thereof facing the combustion chamber 13. The spark plug 40 penetrates the housing H and is fixed to the housing H. At the time of startup, the fuel F is injected into the combustion chamber 13 from the pilot nozzle 29 and diffusion combustion is performed by ignition by the spark plug 40. Subsequently, during normal operation, the premixed gas M injected from the main nozzle 30 into the combustion chamber 13 is combusted, and a first combustion region S <b> 1 is formed in the upstream portion of the combustion cylinder 12. Further, on the downstream side of the first combustion region S1 in the combustion cylinder 12, a plurality of (for example, four) through holes 41 penetrating the outer cylindrical portion 20b of the outer wall 20 of the combustion cylinder 12 are equally spaced in the circumferential direction. Is provided. A chasing burner 42 is attached to a portion of the housing H that faces each through hole 41, and its tip end faces the combustion chamber 13 through the through hole 41. Thus, the second combustion region S2 is formed on the downstream side of the first combustion region S1 by the fuel F injected from the reheating burner 42.

  As shown in FIG. 3, the upstream portion including the head portion 12 a of the combustion cylinder 12 has a double wall structure in which an outer wall 20 and an inner wall 21 are arranged to face each other with a predetermined gap. In this double wall structure, an impingement cooling region 43 is set at the head portion 12 a of the outer wall 20 and the upstream end portion of the cylindrical portion 12 b, and a convection cooling region 44 is set downstream of the impingement cooling region 43. That is, the upstream portion of the combustion cylinder 12 includes an impingement cooling region 43 and a convection cooling region 44. A film cooling region 48 is set on the outer wall 20 on the downstream side of the convection cooling region 44. On the outer wall 20 in the impingement cooling region 43, a plurality of impingement cooling holes 49 are formed at equal intervals for introducing the compressed air A as cooling air A1 toward the inner wall 21 into the double wall.

  In the convection cooling region 44, a turbulent flow generating means 50 </ b> A is provided on the outer peripheral surface of the inner wall 21 on the downstream side of the impingement cooling region 43. The turbulent flow generation means 50A has a configuration in which a plurality of annular ribs extending in the circumferential direction of the inner wall 21 are formed at equal intervals and in parallel with each other. In this embodiment, the case where the impingement cooling hole 49 is formed in the entire convection cooling region 44 in the outer wall 20 is illustrated. However, the impingement cooling is effective only in the upstream portion where the impingement cooling in the convection cooling region 44 is effectively obtained. Only the cooling holes 49 may be provided.

The film cooling region 48 is set by providing a discharge port 51 that opens the space in the double wall in the downstream direction at the downstream end of the convection cooling region 44 that matches the downstream end of the inner wall 21. Since the inner wall 21 is not perforated from the discharge port 51, all of the cooling air A1 flowing toward the downstream side in the space in the double wall becomes the film cooling air A2 of the outer wall 20 in the combustion chamber 13. It is discharged in the direction along the inner peripheral surface. Although not shown in FIG. 2, a large number of small turbulence generating ribs 20e are integrally formed on the entire outer peripheral surface downstream of the convection cooling region 44 in the cylindrical portion 12b of the outer wall 20 in FIG. . The turbulence generating rib 20e also has an effect of promoting the convection cooling portion of the outer wall 20 by the compressed air A passing through the air passage 23.

Spacers 52, 53, and 53 are disposed at three locations corresponding to the upstream end of the head 12 a and the cylindrical portion 12 a of the outer wall 20 and the downstream end of the inner wall 21 in the space within the double wall. These spacers 52, 53, 53 ensure a space between the outer wall 20 and the inner wall 21. As shown in FIG. 4 which is a cross-sectional view taken along the line IV-IV in FIG. 3, the spacer 53 is an annular member in which a large number of projections and depressions 53a and 53b arranged in the circumferential direction are directly formed on the plate material. A cooling air A1 outlet 51 is formed between the outer wall 20, the inner wall 21, and the spacer 53. The spacer 52 provided on the head portion 12a of the outer wall 20 has a single convex portion 52a and two concave portions 52b on both sides in the circumferential direction, as shown in FIG. A plurality of spacers 52 (for example, six) are provided side by side in the circumferential direction.

  The gas turbine combustor 2 of this embodiment includes cooling air introduced into the double wall from the impingement cooling holes 49 formed in the outer wall 20 of the impingement cooling region 43 provided in the upstream portion of the combustion cylinder 12 shown in FIG. A1 collides with the inner wall 21 to impinge cool the inner wall 21. When the cooling air A1 after this impingement cooling flows in the double wall of the convection cooling region 44 on the downstream side, turbulent flow is generated in the cooling air A1 by the turbulent flow generating means 50A provided on the outer peripheral surface of the inner wall 21, Heat transfer from the inner wall 21 to the cooling air A1 is promoted by the turbulent flow of the cooling air A1, and the convection cooling effect by the cooling air A1 is improved.

  In the convection cooling region 44, the cooling air A1 introduced from the impingement cooling holes 49 provided in the outer wall 20 collides with the inner wall 21, so that impingement cooling is also performed in addition to convection cooling, so that the cooling effect is further improved. In particular, in the upstream portion of the convection cooling region 44, the flow rate of the cooling air A1 flowing from the impingement cooling region 43 is not so large and the flow velocity is relatively slow. The compressed air A introduced into the double wall from the impingement cooling hole 49 collides with the inner wall 21 without much interference from the crossflow caused by the cooling air A1 flowing through the space in the double wall. Therefore, impingement cooling is effectively performed at least upstream of the convection cooling region 44.

  Further, in the entire convection cooling region 44, particularly in the downstream portion, the compressed air A introduced into the double wall from the impingement cooling hole 49 of the outer wall 20 is converted into the cooling air A1 generated by the turbulent flow generation means 50A. Since it stirs, the cooling effect by convection cooling improves further.

  Therefore, in the gas turbine combustor 2 of this embodiment, the inner wall 21 corresponding to the upstream portion in the combustion chamber 13 of FIG. 2 where the first high-temperature combustion region S1 is formed is used for impingement cooling with an excellent cooling effect. In addition, since effective and efficient cooling can be achieved by convection cooling, the expected life of the combustion cylinder 12 can be ensured.

  Further, the cooling air A1 in the double wall is provided at the downstream end of the convection cooling region 44 in a state where both the flow rate and the flow velocity increase as it flows from the impingement cooling region 43 to the convection cooling region 44 in FIG. The film cooling air A2 is discharged into the combustion chamber 13 from the discharge port 51 that opens the space in the double wall in the downstream direction. The large amount of film cooling air A2 flows in a layered manner along the inner surface of the outer wall 20 at a high flow rate, so that the high-temperature combustion gas G in the first and second combustion regions S1 and S2 in FIG. The outer wall 20 is effectively film-cooled by acting so as to prevent it. In particular, in this gas turbine combustor 2, since the inner wall 21 is non-porous and the impingement cooling holes 49 are provided in the entire outer wall 20 in the convection cooling region 44 of FIG. Since a large amount of the cooling air A1 is introduced into this, all of the large amount of the cooling air A1 is effectively utilized as the film cooling air A2, so that the outer wall 20 of the combustion cylinder 12 can be cooled with high cooling efficiency. it can.

  Moreover, the combustion cylinder 12 is simply provided with the impingement cooling hole 49 in the outer wall 20 and the turbulent flow generating means 50A made of an annular rib that can be easily formed by etching or machining on the outer peripheral surface of the non-perforated inner wall 21. Therefore, it becomes a simple structure compared to a structure in which many small film cooling holes are formed in a general combustion cylinder and a structure in which a plurality of inner walls and outer walls divided along the axial center direction of the combustion cylinder are overlapped and connected, It can be manufactured at low cost.

  In the above embodiment, the case where the annular rib is provided as the turbulent flow generation means 50A for giving turbulence to the cooling air A1 in the double wall is illustrated, but the turbulent flow generation means 50A is not limited to the annular rib. For example, you may provide the turbulent flow production | generation means 50B as shown in FIG. The turbulent flow generation means 50B has a honeycomb structure in which a number of regular hexagonal cells 59 each including six ribs 58A and 58B protruding from the outer peripheral surface of the inner wall 21 of the combustion cylinder 12 are arranged. In this turbulent flow generation means 50B, a swirling flow 55 is generated when the cooling air A1 gets over the ribs 58B inclined with respect to the flow direction thereof, and the cooling air A1 is stirred by the swirling flow 55 from the inner wall 21. The heat transfer to the cooling air A1 is efficiently performed, so that the convection cooling effect of the inner wall 21 is further improved.

  Moreover, you may provide the turbulent flow generation means 50C as shown in FIG. The turbulent flow generating means 50C has a honeycomb structure in which a large number of regular hexagonal cells 59 similar to the turbulent flow generating means 50B in FIG. 6 are continuously arranged on the outer peripheral surface of the inner wall 21 of the combustion cylinder 12 (FIG. 2). In addition, a cylindrical independent rib 60 having the same height as the ribs 58A and 58B is erected at the center of each cell 59. In the turbulent flow generation means 50C, in addition to the same effects as described with reference to FIG. 5, a vortex 56 of compressed air A is generated behind the independent rib 60 at the center of the cell 59. Since the cooling air A1 is agitated by 56, there is an advantage that the inner wall 21 is cooled evenly in place.

  Furthermore, a turbulent flow generation means 50D as shown in FIG. 8 may be provided. This turbulent flow generation means 50D has a honeycomb structure in which rhombic cells 62 are continuous in a plan view surrounded by four ribs 61, and the ribs 61 forming the four sides of the rhombus all have cooling air A1. Since the swirl flow is generated in the cooling air A1 by all the ribs 61 and the cooling air A1 is sufficiently agitated, the inner wall 21 is efficiently formed. To be cooled.

  Furthermore, you may provide the turbulent flow generation means 50E and 50F as shown to Fig.9 (a) (b). The turbulent flow generating means 50E of FIG. 9A has a honeycomb structure in which parallelogram cells 64 are continuous in a plan view surrounded by four ribs 63, and each cell 64 has a combustion cylinder 12 ( Those adjacent to the circumferential direction R in FIG. 2) are inclined in the opposite direction to the flow direction of the cooling air A1, and are shifted by a predetermined pitch along the axial direction P of the combustion cylinder 12 (FIG. 2). Are arranged. Similarly, the turbulent flow generating means 50F shown in FIG. 9B has a honeycomb structure in which parallelogram cells 69 surrounded by four ribs 68 are continuous, but the turbulent flow shown in FIG. Unlike the generating means 50E, the cells 69 adjacent to each other in the circumferential direction R of the combustion cylinder 12 (FIG. 2) are arranged at the same position along the axial direction P of the combustion cylinder 12 (FIG. 2). The arrangement pitch along the axial direction P is not shifted. Also in these turbulent flow generating means 50E and 50F, a swirl flow is generated in the cooling air A1 by the two ribs 63 and 68 that obliquely intersect the flow direction of the cooling air A1 in the cells 64 and 69, and the cooling air A1. Is sufficiently stirred.

  Furthermore, a turbulent flow generation means 50G as shown in FIG. 10 may be provided. The turbulent flow generation means 50G has a honeycomb structure in which regular triangular cells 71 surrounded by three ribs 70A and 70B are continuous, and one side of each triangle extends along the flow direction of the cooling air A1. The other two sides are formed by diagonal ribs 70B. A triangular shape other than a regular triangle may be used. Regardless of the orientation of the triangle, at least one side intersects the direction of flow of the cooling air A1 at an angle of less than 90 °. Thereby, at least one side generates a swirl flow in the cooling air A1, thereby improving the convection cooling effect.

  The present invention is not limited to the contents shown in the above embodiments, and various additions, modifications or deletions can be made without departing from the gist of the present invention. Included within the scope of the invention.

DESCRIPTION OF SYMBOLS 1 Compressor 12 Combustion cylinder 12a Head part 12b Cylindrical part 13 Combustion chamber 20 Outer wall 21 Inner wall 28 Nozzle unit 43 Impingement cooling area 44 Convection cooling area 49 Impinge cooling hole 50A Turbulent flow generating means (annular rib)
50B-50G Turbulent flow generation means 51 Discharge port A Compressed air A2 Film cooling air

Claims (5)

A part of the combustion cylinder forming the combustion chamber has a double wall structure consisting of an outer wall and an inner wall,
An impingement cooling region and a convection cooling region downstream thereof are set in the upstream portion of the double wall structure,
Impinge cooling holes for introducing compressed air from the compressor toward the inner wall are formed on the outer wall of at least the impingement cooling region of the impingement cooling region and the convection cooling region,
Turbulent flow generating means is provided on the outer peripheral surface of the inner wall of the convection cooling region to disturb the compressed air in the double wall,
A gas turbine combustor having a discharge port for opening the space in the double wall in the downstream direction at the downstream end of the convection cooling region and discharging the compressed air in the double wall as film cooling air .   2. The gas turbine combustor according to claim 1, wherein impingement cooling holes are formed at least upstream of the outer wall in the convection cooling region.   In Claim 1 or 2, the nozzle unit which supplies fuel to a combustion chamber is attached to the head of the combustion cylinder, and the double wall structure is formed in the upstream part including the head in the combustion cylinder. Gas turbine combustor. 4. The gas turbine combustor according to claim 3 , wherein the combustion cylinder has a cylindrical portion continuously provided on a downstream side of the head portion, and the impingement cooling region is formed in an upstream portion of the head portion and the cylindrical portion. .   5. The gas turbine combustor according to claim 1, wherein the turbulent flow generation means is an annular rib concentric with the combustion cylinder. 6.

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