Abstract:
A gas turbine combustor including a fuel nozzle for injecting mixed gas of fuel and air, a cylindrical liner for burning and reacting the mixed gas of fuel and air in a combustion chamber, a transition piece which is a flow path for leading combustion gas generated in the liner to turbine blades, and a transition piece flow sleeve for wrapping an outside surface of the transition piece, wherein a plurality of air introduction holes for introducing air into the transition piece flow sleeve are formed in regions of the transition piece flow sleeve excluding regions which are corner portions of the transition piece flow sleeve in a sectional direction thereof.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional of U.S. application Ser. No. 13/252,262, filed Oct. 4, 2011, which claims priority from Japanese Patent Application 2010-225391, filed on Oct. 5, 2010, the disclosures of which are expressly incorporated by reference herein. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a gas turbine combustor and more particularly to a structure of a gas turbine combustor intending to improve the reliability and cooling property of a transition piece for leading combustion gas generated in a combustion chamber of the gas turbine combustor to the turbine blades. 
     2. Description of Related Art 
     The transition piece composing the gas turbine combustor is a flow path for leading high-temperature and high-pressure combustion gas generated by an oxidation reaction of fuel and air in the combustion chamber of the gas turbine combustor to the turbine blades. 
     The transition piece of the gas turbine combustor is a duct having an entrance portion in a circular shape on the side of the combustion chamber and an exit portion in a fan shape on the side of the turbine blades and therein, high-temperature combustion gas at 1300° C. or higher flows at high speed, so that it is necessary to install some cooling facility to reduce the temperature of the member composing the transition piece to the allowable temperature or lower. 
     As one of the means for cooling the transition piece of the gas turbine combustor, as disclosed in Japanese Patent Laid-open No. 2001-289061, impingement cooling for cooling the transition piece by covering the whole surface of the transition piece of the gas turbine combustor with a transition piece flow sleeve and permitting an air current injected from many air holes formed in the transition piece flow sleeve to collide with the transition piece may be cited. 
     Further, as another one of the means for cooling the transition piece of the gas turbine combustor, as disclosed in Japanese Patent publication No. Hei 7(1995)-52014, there is a method for cooling the end portion of the transition piece of the gas turbine combustor by covering the transition piece of the gas turbine combustor with the transition piece flow sleeve, executing the impingement cooling for the downstream side of the transition piece and convection cooling for the upstream side of the transition piece through convection cooling holes, and permitting cooling air to flow to the end of the transition piece flow sleeve on the turbine side. 
     DOCUMENT OF PRIOR ART 
     Patent Document 1: Japanese Patent Laid-open No. 2001-289061 
     Patent Document 2: Japanese Patent Publication No. Hei 7(1995)-52014 
     SUMMARY OF THE INVENTION 
     In the cooling structure of the transition piece of the gas turbine combustor disclosed in Japanese Patent Laid-open No. 2001-289061, many air holes are formed over the entire surface of the transition piece flow sleeve for surrounding the transition piece. Further, also in the cooling structure of the transition piece of the gas turbine combustor disclosed in Japanese Patent Publication No. Hei 7(1995)-52014, many air holes are formed over the entire surface of the downstream portion of the transition piece flow sleeve. 
     Here, a general manufacturing method of the transition piece flow sleeve with air holes formed will be explained. The transition piece flow sleeve is manufactured by performing a boring process of many air holes for a flat sheet of a raw material and then press-molding it. 
     However, the section of the exit portion of the transition piece flow sleeve is fan-shaped, so that the corner portion of the exit portion of the transition piece flow sleeve is bent at an angle of 90° or more. Therefore, a problem arises that at the time of press molding, the air holes formed in the corner portion of the transition piece flow sleeve are stretched and deformed. And, when the deformation amount of the air holes is large, there is a possibility that the surroundings of the air holes may be cracked. 
     Further, when the gas turbine is in operation, the air pressure outside the transition piece flow sleeve is higher than that inside the flow sleeve, so that due to the pressure difference between the inside and the outside, force is acted in the direction for compressing the transition piece flow sleeve toward the inside from the outside. At this time, particularly in the corner portion of the transition piece flow sleeve, stress is concentrated. Therefore, if air holes are formed in the corner portion of the transition piece flow sleeve, the strength of the surrounding member of the corner portion of the transition piece flow sleeve is reduced, thus there is a possibility that due to the stress in operation, there is a possibility that the main unit of the transition piece flow sleeve may be deformed. 
     Furthermore, the transition piece is impingement-cooled by air injected from the air holes of the transition piece flow sleeve, though when air holes are formed in the corner portion of the transition piece flow sleeve, the cooling air injected from the air holes of the corner portion toward the transition piece flows on both sides along the corner portion of the transition piece. This air current is called a cross flow and it may be considered that the air current weakens the effect of collision of the jet flow injected from the air holes in the vicinity of the corner portion to the transition piece and reduces the impingement cooling property. 
     An object of the present invention is to provide a gas turbine combustor for suppressing the occurrence of deformation and cracking in the transition piece flow sleeve of the gas turbine combustor and intending to improve the reliability of the transition piece flow sleeve and improve the cooling property of the transition piece. 
     A gas turbine combustor of the present invention, comprising a fuel nozzle for injecting mixed gas of fuel and air, a cylindrical liner for burning and reacting the mixed gas of fuel and air in the combustion chamber, a transition piece which is a flow path for leading combustion gas generated in the liner to the turbine blades, and a transition piece flow sleeve for wrapping the outside surface of the transition piece, wherein a plurality of air introduction holes for introducing air into the transition piece flow sleeve are formed in the region of the transition piece flow sleeve excluding the region which is the corner portion of the transition piece flow sleeve in the sectional direction thereof. 
     Also, a gas turbine combustor of the present invention, comprising a fuel nozzle for injecting mixed gas of fuel and air, a cylindrical liner for burning and reacting the mixed gas of fuel and air in the combustion chamber, the transition piece which is a flow path for leading combustion gas generated in the liner to the turbine blades, and a transition piece flow sleeve for wrapping the outside surface of the transition piece, 
     wherein a plurality of first air introduction holes are formed in regions which are corner portions of the transition piece flow sleeve in a sectional direction thereof, a plurality of second air introduction holes are formed in regions of the transition piece flow sleeve excluding the regions which are the corner portions of the transition piece flow sleeve, and 
     a diameter of the first air introduction holes formed in the region of the corner portion of the section of the transition piece flow sleeve is made smaller than a diameter of the second air introduction holes formed in the region of the transition piece flow sleeve excluding the regions of the corner portions. 
     According to the present invention, a gas turbine combustor for suppressing the occurrence of deformation and cracking in the transition piece flow sleeve of the gas turbine combustor and intending to improve the reliability of the transition piece flow sleeve and improve the cooling property of the transition piece can be realized. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram showing the constitution of the gas turbine to which the gas turbine combustor of the present invention is applied; 
         FIG. 2  is a partial cross sectional view showing the structure of the transition piece of the gas turbine combustor that is the first embodiment of the present invention; 
         FIG. 3  is a cross sectional view taken along the line A-A of the transition piece of the gas turbine combustor of the first embodiment shown in  FIG. 2 ; 
         FIG. 4  is a partial diagram showing only the transition piece flow sleeve of the gas turbine combustor of the first embodiment of the present invention shown in  FIG. 2 ; 
         FIG. 5  is a schematic diagram showing the outline of deformation of a hollow article in a rectangular parallelepiped shape when pressure is applied from the outside; 
         FIG. 6  is a schematic diagram showing the outline of deformation of the transition piece flow sleeve of the gas turbine combustor when pressure is applied from the outside; 
         FIG. 7  is a schematic diagram of the transition piece flow sleeve with the curvature of the outside surface portion of the transition piece flow sleeve specified showing the form of the transition piece flow sleeve of the gas turbine combustor which is an embodiment of the present invention; 
         FIG. 8  is a schematic diagram of the transition piece flow sleeve with the width of the transition piece flow sleeve specified showing the form of the transition piece flow sleeve of the gas turbine combustor which is an embodiment of the present invention; 
         FIG. 9  is a schematic diagram showing the air current on the outside surface of the transition piece when air holes are formed in the corner portion showing the partial cross sectional view of the transition piece flow sleeve of the gas turbine combustor; 
         FIG. 10  is a schematic diagram showing the air current on the outside surface of the transition piece when no air holes are formed in the corner portion showing a partial cross sectional view of the transition piece flow sleeve of the gas turbine combustor which is the first embodiment and second embodiment of the present invention; 
         FIG. 11  is a partial cross sectional view showing the structure of the transition piece of the gas turbine combustor that is the second embodiment of the present invention; 
         FIG. 12  is a cross sectional view taken along the line B-B of the transition piece of the gas turbine combustor of the second embodiment shown in  FIG. 11 ; and 
         FIG. 13  is a partial diagram showing only the transition piece flow sleeve of the gas turbine combustor of the second embodiment shown in  FIG. 11 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The gas turbine combustor that is an embodiment of the present invention will be explained below with reference to the accompanying drawings. 
     Embodiment 1 
     The gas turbine combustor that is the first embodiment of the present invention will be explained below by referring to  FIGS. 1 to 4 . 
       FIG. 1  is a schematic diagram showing the constitution of the gas turbine unit to which a gas turbine combustor  1  of the first embodiment of the present invention is applied. As shown in  FIG. 1 , high-pressure air  120  compressed and introduced by an air compressor  110  is introduced into a plenum chamber  140  via a diffuser  130  and flows into the gap between a transition piece  30  and a transition piece flow sleeve  10  from air introduction holes  20  formed in the transition piece flow sleeve  10  composing the gas turbine combustor  1 . 
     The high-pressure air  120  flowing into the gap between the transition piece  30  and the transition piece flow sleeve  10  flows through the gap between a liner  40  and a liner flow sleeve  50  arranged on the concentric circle on the outer periphery of the liner, then reverses the flow, is mixed with fuel injected from fuel nozzles  60 , is injected into a combustion chamber  70 , burns in the combustion chamber  70  formed inside the liner  40 , forms a flame, and thereby becomes high-temperature and high-pressure combustion gas  80 . 
     The combustion gas  80  generated in the combustion chamber  70  of the gas turbine combustor  1  flows down in the transition piece  30  and is introduced into a turbine  160 . The gas turbine unit converts the workload generated when the high-temperature and high-pressure combustion gas  80  expands adiabatically to the shaft rotation force by the turbine  160 , and thereby obtains output from a generator  170  connected to the turbine  160 . 
     The air compressor  110  and the generator  170  are connected to the turbine  160  with one shaft. However, the air compressor  110 , the turbine  160 , and the generator  170  may be structured so as to connect to each other with two or more shafts. Further, generally, the gas turbine unit widely used in a thermal power plant adopts a constitution that for the rotary shaft of the turbine, the gas turbine combustor  1  is arranged radially in the form of a plurality of cans. 
     The gas turbine combustor  1  which is the first embodiment of the present invention will be explained in more detail by referring to  FIGS. 2 to 4 . 
     The structure of the gas turbine combustor  1  of this embodiment shown in  FIGS. 2 to 4  is composed of the cylindrical liner  40  for internally forming the combustion chamber  70  of the gas turbine combustor  1 , the cylindrical liner flow sleeve  50  arranged on the concentric circle with the liner on the outer periphery side of the liner  40 , the transition piece  30  installed on the downstream side of the liner  40 , the transition piece flow sleeve  10  for covering the transition piece  30  at a predetermined flow path interval from the transition piece  30 , and the plurality of air holes  20  formed in the transition piece flow sleeve  10 . 
     The air discharged from the air compressor  110  is introduced from the air holes  20  formed in the transition piece flow sleeve  10 , and the jet flow thereof collides with the transition piece  30 , thereby impingement-cooling the downstream portion of the transition piece  30  exposed to the high-temperature combustion gas  80  generated in the combustion chamber  70  of the gas turbine combustor  1 . The air impingement-cooling the downstream portion of the transition piece  30 , thereafter, flows around the transition piece  30  at high speed, thereby convection-cooling the main unit of the transition piece  30 . 
     The characteristic of the structure of the gas turbine combustor  1  of this embodiment is that, as shown in  FIGS. 2 to 4 , the air holes  20  formed in the transition piece flow sleeve  10  are formed over the entire region of the transition piece flow sleeve  10  excluding corner portions  11  and  12  of the transition piece flow sleeve  10 . 
       FIG. 4  is an external view of the exit portion in the single state of the transition piece flow sleeve  10  of the gas turbine combustor  1  of this embodiment, showing the state that the plurality of air holes  20  are formed over the entire region of the transition piece flow sleeve  10  excluding the corner portions  11  and  12  of the transition piece flow sleeve  10 . 
     On the other hand, when manufacturing the transition piece flow sleeve  10  of the gas turbine combustor  1 , generally, the transition piece flow sleeve  10  is manufactured by pressing and molding a flat sheet of a raw material, though when forming the air holes  20  in the transition piece flow sleeve  10 , it is said that a method for performing a boring process at the stage of a flat sheet of a raw material is good. 
     As a methodology, there is a measure available for press molding the transition piece flow sleeve  10  and then performing a boring process of the air holes  20 , though for that purpose, a boring machine operating three-dimensionally is necessary and time is required to set the position and angle for boring, so that not only the boring time becomes longer but also the boring cost is increased. Furthermore, when performing the boring process of the air holes  20 , to keep the transition piece flow sleeve  10  in an undeformed three-dimensional shape, the necessity of installing a reinforcing member on the transition piece flow sleeve  10  may be considered. 
     For the aforementioned reason, to realize shortening of the boring time at a low cost, it is said that a method for performing the boring process of the air holes  20  at the stage of a flat sheet of a raw material of the transition piece flow sleeve  10  and press molding it is good. 
     However, the transition piece  30  and the transition piece flow sleeve  10  have a circular entrance portion and a fan-shaped exit portion and at the four corner portions of the exit portion, the two units are bent at an angle of almost 90°. When press molding the flat sheet, at the bending portion, force is applied in the pulling direction of the raw material sheet, so that a problem arises that when pressing the bored flat sheet, the air holes  20  formed at the corner portions of the transition piece flow sleeve  10  are stretched and deformed. At this time, when the deformation amount is large, there is a possibility that the surroundings of the air holes may be cracked. 
     Furthermore, when the gas turbine unit is in operation, the air pressure outside the transition piece flow sleeve  10  is higher than that inside the transition piece flow sleeve  10 , so that due to the pressure difference between the inside and the outside, force is acted in the direction for compressing the transition piece flow sleeve  10  toward the inside from the outside. At this time, particularly in the corner portions  11  and  12  of the transition piece flow sleeve  10 , stress is concentrated. 
     The reason that the stress is concentrated in the corner portions  11  and  12  of the transition piece flow sleeve  10  will be explained by referring to the schematic diagrams of  FIGS. 5 and 6 . As shown in  FIG. 5 , generally, if an article  16  in a rectangular parallelepiped shape is applied pressure  15  from the surroundings, it is deformed as shown by a line  17 . At this time, the deformation amounts of the four peak portions (corner portions) are large, so that large stress is applied to the corner portions. The same may be said with the transition piece flow sleeve  10  of the gas turbine combustor  1  and as shown in  FIG. 6 , if the pressure  15  is applied from the outside of the transition piece flow sleeve  10 , an outside surface line  13  of the transition piece flow sleeve  10  indicated by a solid line is deformed like an outside surface line  14  indicated by a dashed line and large stress in the bending direction is applied to the corner portions  11  and  12  of the transition piece flow sleeve  10 . 
     Therefore, when air holes are formed in the corner portions  11  and  12  of the transition piece flow sleeve  10 , the strength of the surrounding members of the corner portions  11  and  12  is reduced, thus due to the stress caused by the pressure difference between the inside and the outside when the gas turbine unit is in operation, there is a possibility that the main unit of the transition piece flow sleeve  10  may have large plastic deformation. 
     Therefore, in the transition piece flow sleeve  10  of the gas turbine combustor  1  of this embodiment, with reference to the air holes  20  formed in the transition piece flow sleeve  10 , a plurality of air holes are arranged over the entire region of the transition piece flow sleeve  10  excluding the region of the corner portions  11  and  12  of the transition piece flow sleeve  10 , thus at the time of manufacture of the transition piece flow sleeve  10 , the occurrence of air holes  20  deformation and cracking can be avoided and the deformation of the transition piece flow sleeve  10  when the gas turbine unit is in operation can be prevented. 
     The installation region of the air holes  20  in the transition piece flow sleeve  10  of the gas turbine combustor  1  of this embodiment will be explained by referring to  FIGS. 7 and 8 . In  FIGS. 7 and 8 , the outside surface line  13  in the section of the exit portion of the transition piece flow sleeve  10  is shown. 
     As shown in  FIG. 7 , the transition piece flow sleeve  10  is formed by regions of a plurality of radii of curvature where the respective radii of curvature for specifying the external form of the transition piece flow sleeve  10  are different from each other. In the transition piece flow sleeve  10  shown in  FIG. 7 , the regions are respectively formed assuming the radius of curvature within the range of L1 on the back side which is the upper side of the transition piece flow sleeve  10  (hereinafter, indicated as the back side) as R1, the radius of curvature within the range of L5 on the abdomen side which is the lower side of the transition piece flow sleeve  10  (hereinafter, indicated as the abdomen side) as R3, the radius of curvature within the range of L2 in the back side corner portion which is the interval between the back side and the side of the transition piece flow sleeve  10  as R2, and the radius of curvature within the range of L4 in the abdomen side corner portion which is the interval between the abdomen side and the side of the transition piece flow sleeve  10  as R2. 
     As a range of forming the air holes  20  in the transition piece flow sleeve  10  shown in the gas turbine combustor  1  of this embodiment, among a plurality of regions for specifying the form of the outside surface portion of the transition piece flow sleeve  10  by different values of radii of curvature, it is desirable to form the air holes  20  in a region excluding regions where the values of the radii of curvature are smaller than the radii of curvature in other regions. 
     Explaining the radii of curvature of different values for specifying the form of the outside surface portion of the transition piece flow sleeve  10  by referring to  FIG. 7 , in comparison of the radii of curvature R1, R2, and R3, R2 is smaller than R1 and R3, so that in the regions of L1, L3, and L5 of the transition piece flow sleeve  10  excluding the regions of L2 and L4 of R2, the plurality of air holes  20  are formed. 
     In addition to the aforementioned method due to the difference in the radius of curvature, as shown in  FIG. 8 , on the basis of the maximum width W of the transition piece flow sleeve  10 , the installation region of the air holes  20  may be decided. For example, on the back side of the transition piece flow sleeve  10 , in the region X1 of 80% or more of the maximum width W of the transition piece flow sleeve  10 , on the abdomen side of the transition piece flow sleeve  10 , in the region X3 of 60% or more of the maximum width W, and on both sides of the transition piece flow sleeve  10 , in each of the regions X2 which are a straight line portion, a plurality of air holes  20  may be formed. 
     Further, in the gas turbine combustor  1  of this embodiment, not only the transition piece flow sleeve  10  can be suppressed from deformation and cracking but also the cooling property of the transition piece  30  can be improved. 
     The schematic diagram of the air current on the outside surface of the transition piece  30  of the gas turbine combustor  1  of this embodiment is shown in  FIGS. 9 and 10 .  FIGS. 9 and 10  are a drawing in which the vicinity of the corner portion  11  of the transition piece flow sleeve  10  shown in  FIG. 3  is enlarged. 
       FIG. 9  shows the structure that in the corner portion of the transition piece flow sleeve  10  of the gas turbine combustor  1 , air holes  22  are formed. In this structure, air  1  injected from the air holes  22  formed in the corner portion collides with the transition piece  30  in a right angle shape, then becomes a current flowing in the direction of jet flow  2  adjacent along the surface of the transition piece  30 , and thereby obstructs the current of collision of the jet flow  2  with the surface of the transition piece  30 . 
     Here, the transition piece  30  is impingement-cooled by air jet flow  3  from the plurality of air holes  20  formed, so that when the air jet flow does not collide with the outside surface of the transition piece  30 , the impingement cooling property becomes worse. Such a current for obstructing the current of jet flow is generally referred to as cross flow and it is a cause of deterioration of the impingement cooling property. 
     Therefore, in the structure of the transition piece flow sleeve  10  shown in  FIG. 9 , in the periphery of the corner portion of the transition piece  30 , the jet flow  3  hardly collides with the surface of the transition piece  30 , so that deterioration of the impingement cooling property is a concern. 
     Therefore, the transition piece flow sleeve  10  of the gas turbine combustor  1  of this embodiment, as shown in  FIG. 10 , is structured so that no air holes are formed in the corner portions of the transition piece flow sleeve  10 , and in the region of the transition piece flow sleeve  10  excluding the corner portions of the transition piece flow sleeve  10 , the plurality of air holes  20  are formed, thus the occurrence of cross flow in the periphery of the corner portions of the transition piece flow sleeve  10  can be avoided, thereby the deterioration of the cooling property in the periphery of the corner portions of the transition piece  30  can be suppressed. 
     Further, also the corner portions of the transition piece  30  are convection-cooled by a large amount of high-speed air flowing in from the air holes  20  formed on both sides of the corner portions, so that the members of the transition piece  30  will not become high in temperature. 
     Further, no air holes are formed in the corner portions of the transition piece flow sleeve  10  and a plurality of air holes  20  are formed in all the regions of the transition piece flow sleeve  10  except the corner portions, thus a large amount of cooling air can be distributed to the transition piece flow sleeve  10  except the corner portions, so that the cooling property of the whole transition piece  30  is improved. 
     According to this embodiment, a gas turbine combustor for suppressing the occurrence of deformation and cracking in the transition piece flow sleeve of the gas turbine combustor and intending to improve the reliability of the transition piece flow sleeve and improve the cooling property of the transition piece can be realized. 
     Embodiment 2 
     Next, the gas turbine combustor  1  which is the second embodiment of the present invention will be explained by referring to  FIGS. 11 to 13 . The gas turbine combustor  1  which is the second embodiment of the present invention is the same in the basic constitution as for the gas turbine combustor  1  of the first embodiment shown in  FIGS. 1 to 4 , so that the explanation of the common constitution to the two is omitted and the different portions will be explained. 
     As shown in  FIGS. 11 to 13 , in the gas turbine combustor  1  of this embodiment, in the corner portions  11  and  12  of the transition piece flow sleeve  10 , air holes  21  with a diameter smaller than that of the air holes  20  in other regions other than the corner portions  11  and  12  are formed. 
       FIG. 13  shows an external view of the exit portion in the single state of the transition piece flow sleeve  10 , wherein the air holes  21  with a diameter smaller than that of the air holes  20  in other regions other than the corner portion  11  are formed. 
     The gas turbine combustor  1  of this embodiment shown in  FIGS. 11 to 13  is a measure applied to a situation that due to a rise in the combustion gas temperature, the cooling property of the corner portions of the transition piece  30  needs to be improved more. 
     If air holes are formed in the corner portions  11  and  12  of the transition piece flow sleeve  10 , deformation of the air holes at the time of press molding and deformation of the transition piece flow sleeve  10  due to reduction in the member strength when the gas turbine is in operation are a concern, though if the diameter of the air holes  21  is made smaller than that of the air holes  20 , the aforementioned deformations are reduced to the greatest degree possible. 
     According to this embodiment, a gas turbine combustor for suppressing the occurrence of deformation and cracking in the transition piece flow sleeve of the gas turbine combustor and intending to improve the reliability of the transition piece flow sleeve and improve the cooling property of the transition piece can be realized. 
     The present invention can be applied to a gas turbine combustor having a transition piece flow sleeve in a transition piece of the combustor.