Combustion chamber outlet cooling structure

Abstract

The invention discloses a combustion chamber outlet cooling structure which is characterized in that an initial section of a small elbow is inserted into an inner beak ring, and an impact hole is formed in the inner beak ring and used for introducing part of inner two-channel airflow into a combustion chamber outlet runner, so that a wall-attached cooling air film is formed to cover the initial section of the small elbow. And a plurality of circles of diverging hole groups are formed in the small elbow middle section, so that part of inner two-channel airflow is introduced into the combustion chamber outlet runner through the plurality of circles of diverging hole groups, and a large cooling air film is formed at the large-curvature part of the small elbow middle section. The small elbow outlet section is provided with a tongue groove cooling structure and an air film groove hole so that part of inner two-channel airflow can be led into the tongue groove cooling structure to impact the tongue groove cooling structure, and a cooling air film flowing along the profile of the small elbow outlet section in a wall attaching mode is formed. The small elbow further comprises an annular upper edge plate supporting ring located behind the outlet section of the small elbow. By means of the structure, release of expansion stress in the thermal state can be guaranteed, and the inner ring wall face of the flame tube cannot be heated, arched and deformed to cause other faults or safety accidents.

Description

Technical Field

[0001] The invention relates to the technical field of aeroengines, and in particular to a combustion chamber outlet cooling structure. Background Art

[0002] Small and medium-sized gas turbine engines have the characteristics of high speed and high temperature rise. In order to avoid rotor dynamics problems, recirculation type combustion chambers are often considered when selecting combustion chambers. The small elbow is a unique structure in the recirculation combustion chamber. It forms the inner two-branch channel of the combustion chamber with the combustion chamber casing, and forms a high-temperature gas channel together with the large elbow and the inner and outer rings of the flame tube. The high-temperature gas passes through the large and small elbows and turns 180° to enter the gas turbine guide. The small elbow is subjected to extremely high temperatures when working. With the future development direction of high temperature rise and high speed of engines, it is extremely important to innovate the structure and cooling design of the small elbow.

[0003] At present, small bends mainly include two forms: double-wall structure and single-wall structure. Existing double-wall small bends often use impact cooling. The cooling gas after impact flows out to the gas turbine guide through the gap between the double walls and cools the upper edge plate of the gas turbine guide. Single-wall small bends are often designed as a whole with the inner ring of the flame tube. The impact holes on the inner ring of the flame tube form the initial air film of the small bend to protect the body. By adding an air film groove at the tail end of the small bend, the cooling of the small bend can be enhanced while cooling the upper edge plate of the gas turbine guide.

[0004] The existing double-wall small bend pipe has more parts, is difficult to machine, has high processing costs, and has multiple welds. Due to the large temperature gradient at the small bend pipe, the deformation of the inner and outer walls of the small bend pipe is inconsistent, which easily causes weld cracks. Once deformed, the cooling effect of the guide is greatly reduced.

[0005] Due to the extremely high temperature at the combustion chamber outlet, the small bend is subjected to greater thermal stress. The existing single-wall small bend is designed as an integral small bend with the inner ring of the flame tube, and has a small space for releasing thermal stress, which may eventually cause the thinner-walled inner ring of the flame tube to bulge and deform. On the other hand, the middle section of the small bend lacks cooling air, and the small bend is directly subjected to the erosion of high-temperature combustion gas, with a great risk of cracking and falling off. Summary of the invention

[0006] The present invention provides a combustion chamber outlet cooling structure to solve the technical problem that the thermal stress release space in the existing conventional structure is small, which may eventually cause the inner ring of the flame tube with a thin wall to bulge and deform.

[0007] The technical solution adopted by the present invention is as follows:

[0008] A combustion chamber outlet cooling structure comprises an inner ring bird beak ring at the tail of the inner ring of the flame tube, a small curved pipe with a single-layer wall and a gas turbine guide, wherein the starting section of the small curved pipe located at the air inlet end of the small curved pipe is inserted into the inner ring bird beak ring through the opening of the inner ring bird beak ring, and an impact hole is provided on the inner ring bird beak ring to introduce part of the inner two-stream airflow into the combustion chamber outlet flow channel after passing through the impact hole and the bird beak ring cavity of the inner ring bird beak ring, so as to form a wall-adhering cooling air film in the combustion chamber outlet flow channel to cover the starting section of the small curved pipe; a plurality of circles of divergent holes arranged in sequence along the radial direction are provided on the middle section of the small curved pipe located in the middle part of the small curved pipe, so as ... introduce part of the inner two-stream airflow into the combustion chamber outlet flow channel after passing through the impact hole and the bird beak ring cavity of the inner ring bird be The channel airflow is introduced into the combustion chamber outlet flow channel through a plurality of circles of divergent hole groups to form a large cooling air film at the large curvature in the middle section of the small bend pipe; a tongue-and-groove cooling structure and an air film slot hole are provided on the small bend pipe outlet section located at the exhaust end of the small bend pipe, so as to introduce part of the inner two channel airflows into the impact tongue-and-groove cooling structure through the air film slot hole to form a cooling air film flowing along the wall of the small bend pipe outlet section profile to cool the small bend pipe outlet section and the upper edge plate of the gas turbine guide; the small bend pipe also includes an annular upper edge plate support ring located behind the small bend pipe outlet section, and the gas turbine guide is arranged at the exhaust end of the small bend pipe and is located within the upper edge plate support ring.

[0009] Furthermore, a plurality of impact holes are arranged in sequence and at intervals on the circumference of the inner bird's beak ring; the plurality of impact holes have the same diameter and are arranged in sequence and at intervals in a sparse and dense manner along the circumference; or, the plurality of impact holes have different diameters and are arranged in sequence and at even intervals along the circumference.

[0010] Furthermore, there is an axial gap δ between the starting section of the small bend pipe and the bottom of the bird's beak ring cavity, 0.5mm≤δ≤3.5mm; there is a radial gap θ between the inner ring surface of the starting section of the small bend pipe and the inner ring surface of the bird's beak ring cavity, 0.07mm≤θ≤0.15mm; there is a radial gap D between the outer ring surface of the starting section of the small bend pipe and the outer ring surface of the bird's beak ring cavity, there is an axial gap L between the bottom of the bird's beak ring cavity to the end faces of the inner ring and the outer ring of the bird's beak ring, and D / L=0.1~0.2, and the angle α between the center line of the impact hole and the outer ring surface of the bird's beak ring cavity is related to D / L, the larger the D / L, the larger the angle α is to 90°, and the smaller the D / L is, the smaller the angle α is to greater than 0°.

[0011] Furthermore, each circle of divergent hole groups includes a plurality of divergent holes arranged in sequence along the circumferential direction, and the plurality of divergent holes of two adjacent circles of divergent hole groups are arranged one by one in a staggered manner along the circumferential direction; the tangential angle of the divergent holes of the remaining circles of divergent hole groups except the innermost circle is 80° to 100°, and the punching angle is 20° to 30°; the tangential angle of the divergent holes of the innermost circle of the divergent hole group is greater than 0° to 15°, and the punching angle is less than 30°

[0012] Furthermore, the outlet section of the small bend pipe is concavely extended to form an annular air film groove, and an annular tongue ring and tail ring located on both sides of the air film groove; the air film groove and the tongue ring form a tongue groove cooling structure; the air film groove hole is opened on the tail ring and connected to the air film groove to introduce part of the two inner channel airflows into the impact tongue ring, thereby forming a cooling air film that flows along the wall of the outlet section of the small bend pipe.

[0013] Furthermore, there are multiple air film slots, and the multiple air film slots are evenly spaced along the circumferential direction; the height of the air film slots is 1 mm to 2 mm.

[0014] Furthermore, the inner ring of the starting section of the small bend pipe is provided with a chamfer; and a thermal barrier coating is sprayed on the gas side profile of the small bend pipe.

[0015] Furthermore, the gas turbine guide vane includes guide vanes arranged in sequence along the circumferential direction, the guide vane includes a blade body and an upper edge plate, the upper edge plate is arranged at intervals corresponding to the upper edge plate support ring; the upper edge plate support ring is provided with branch ring holes arranged in sequence along the circumferential direction and penetrating therethrough, so as to introduce part of the two inner channel air flows through the branch ring holes and the upper edge plate into the blade body; the combustion chamber outlet cooling structure also includes a large bend pipe arranged at intervals outside the small bend pipe, and the large bend pipe flange edge is provided with flange side holes arranged in sequence along the circumferential direction and penetrating therethrough, so as to introduce the air flow outside the large bend pipe into the gas turbine guide vane and the blade body through the flange side holes.

[0016] Furthermore, the combustion chamber outlet cooling structure also includes a positioning pin, which is inserted into the upper edge plate after interference passing through the upper edge plate support ring to position the small bend pipe; the support ring holes and flange side holes are respectively arranged at even intervals along the circumferential direction, and the number of the two is proportional to the number of guide vanes.

[0017] Furthermore, the radial end surface of the outlet end of the upper edge plate support ring is concave to form a mounting ring groove, and the inner ring on the inner side of the mounting ring groove opens in sequence along the circumferential direction to form a boss; the combustion chamber outlet cooling structure also includes a special-shaped sealing ring clamped in the mounting ring groove, and the special-shaped sealing ring is used to seal the radial gap between the outlet end of the upper edge plate support ring and the outlet side of the upper edge plate.

[0018] The present invention has the following beneficial effects:

[0019] In the combustion chamber outlet cooling structure of the present invention, it is calculated that under the maximum thermal state, the wall temperature of the inner ring of the flame tube can reach up to about 1000°C, and the local average stress is more than 200 MPa. The inner ring of the flame tube is a large-diameter thin-walled part with a limited stress resistance level. Therefore, in the cooling structure of the present invention, the starting section of the small bend pipe located at the air inlet end of the small bend pipe is directly inserted into the bird's beak ring cavity of the inner ring bird's beak ring, and is not designed as an integral part with the inner ring bird's beak ring. That is, the small bend pipe and the inner ring of the flame tube are designed separately in the present invention, which is not only conducive to assembly, but also can ensure the release of expansion stress under hot state, so that the inner ring wall of the flame tube is not deformed by heat and causes other faults or safety accidents, and solves the problem of "small thermal stress release space, which may eventually lead to a thick wall" in the existing structure. The technical problem of "arching and deformation of the inner ring of the thin flame tube" is solved; in the cooling structure of the present invention, the upper edge plate support ring of the upper edge plate support plate used as the gas turbine guide is an integral part with the small bend pipe, which is formed by integral forging machining, thereby reducing the number of parts and reducing the difficulty of assembling the gas turbine guide; in the cooling structure of the present invention, a tongue-and-groove cooling structure is also added at the outlet of the small bend pipe. Compared with ordinary divergent cooling, the cooling air film at the outlet of the tongue-and-groove cooling structure has a long coverage distance along the flow direction and a large air film thickness, which can effectively reduce the near-wall gas temperature of the outlet section of the small bend pipe to a certain extent, thereby reducing the heat load of the upper edge plate of the gas turbine guide; the cooling structure of the present invention has been tested for combustion chamber components, whole machine bench tests and field test flights, and the effect is good.

[0020] In addition to the above-described purposes, features and advantages, the present invention has other purposes, features and advantages. The present invention will be further described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0022] Figure 1 2 is a schematic diagram of the main structure of the combustion chamber outlet cooling structure of the preferred embodiment of the present invention;

[0023] Figure 2 yes Figure 1 Schematic diagram of center support ring hole / flange side hole;

[0024] Figure 3 yes Figure 1 Schematic diagram of positioning of small and medium-sized elbows with gas turbine guides through positioning pins;

[0025] Figure 4 yes Figure 1 A schematic diagram of the structure of a boss formed on the inner ring inside the middle mounting ring groove;

[0026] Figure 5 yes Figure 1 Schematic diagram of divergent holes on small and medium-sized elbows;

[0027] Figure 6 yes Figure 1 Schematic diagram of the impact hole on the inner ring bird beak ring Figure 1 ;

[0028] Figure 7 yes Figure 1 Schematic diagram of the impact hole on the inner ring bird beak ring Figure 2 ;

[0029] Figure 8 yes Figure 1 Schematic diagram of the overlap dimensions of the starting section of the small and medium-sized elbow and the inner ring bird's beak ring;

[0030] Fig. 9 yes Figure 1 Schematic diagram of the layout of divergent holes in the middle section of small and medium-sized elbows;

[0031] Fig.10 yes Fig. 9 Schematic diagram of the angle at which the central divergent hole is opened in the middle section of the small elbow.

[0032] Legend:

[0033] 10. Small bend; 101. Thermal barrier coating; 102. Divergent holes; 103. Air film slots; 104. Tongue ring; 105. Pin holes; 106. Upper edge plate support ring; 107. Boss; 108. Support ring hole; 20. Inner ring bird beak ring; 201. Impact hole; 30. Large bend; 301. Flange side hole; 40. Gas turbine guide; 401. Upper edge plate; 402. Blade; 50. Airflow outside the large bend; 70. Combustion chamber outlet flow channel; 80. Positioning pin; 90. Special-shaped sealing ring. DETAILED DESCRIPTION

[0034] The embodiments of the present invention are described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways as defined and covered below.

[0035] Reference Figure 1The preferred embodiment of the present invention provides a combustion chamber outlet cooling structure, comprising an inner ring bird beak ring 20 at the tail of the inner ring of the flame tube, a small curved pipe 10 with a single wall, and a gas turbine guide 40. The starting section of the small curved pipe located at the air inlet end of the small curved pipe 10 is inserted into the inner ring bird beak ring 20 through the opening of the inner ring bird beak ring 20. The inner ring bird beak ring 20 is provided with an impact hole 201, which is used to introduce part of the inner two-stream airflow into the combustion chamber outlet flow channel 70 after passing through the impact hole 201 and the bird beak ring cavity of the inner ring bird beak ring 20, so as to form a wall-attached cooling air film in the combustion chamber outlet flow channel 70 to cover the starting section of the small curved pipe. A plurality of circles of divergent holes arranged in sequence along the radial direction are provided in the middle section of the small curved pipe located in the middle of the small curved pipe 10, so as to introduce part of the inner two-stream airflow into the combustion chamber outlet flow channel 70 through the plurality of circles of divergent holes, so as to form a large cooling air film at the large curvature of the middle section of the small curved pipe. The outlet section of the small bend pipe located at the exhaust end of the small bend pipe 10 is provided with a tongue-and-groove cooling structure and an air film slot hole 103, which is used to introduce part of the two inner channel airflows into the impact tongue-and-groove cooling structure through the air film slot hole 103, so as to form a cooling air film flowing along the profile of the outlet section of the small bend pipe and adhering to the wall, so as to cool the outlet section of the small bend pipe and the upper edge plate 401 of the gas turbine guide 40. The small bend pipe 10 also includes an annular upper edge plate support ring 106 located behind the outlet section of the small bend pipe, and the gas turbine guide 40 is arranged at the exhaust end of the small bend pipe 10 and is located in the upper edge plate support ring 106.

[0036] When the combustion chamber outlet cooling structure of the present invention is working, the temperature of the gas discharged from the combustion chamber into the combustion chamber outlet flow channel 70 is relatively high, and the small bend pipe 10 needs to withstand high temperature erosion, which is very prone to failures such as ablation. Therefore, in the cooling scheme of the present invention, firstly, an impact hole 201 is opened on the inner ring bird's beak ring 20 at the outlet end of the inner ring of the flame tube, and a part of the inner two-channel airflow from the inner two-channel is introduced into the bird's beak ring cavity in the inner ring bird's beak ring 20 through the impact hole 201. This part of the airflow then enters the combustion chamber outlet flow channel 70 from the bird's beak ring cavity and forms a good wall-adhering cooling air film to cover the starting section of the small bend pipe; secondly, a radial opening is opened on the middle section of the small bend pipe. A plurality of circles of divergent hole groups are arranged at intervals in sequence, and part of the inner two-channel airflow passes through the divergent hole group to enter the combustion chamber outlet flow channel 70, forming a large cooling air film at the large curvature position in the middle section of the small bend, cooling the middle section of the small bend and further cooling the metal matrix of the small bend 10; finally, a tongue-and-groove cooling structure and an air film slot hole 103 are arranged on the small bend end outlet section, and part of the inner two-channel airflow is introduced through the air film slot hole 103 to impact the tongue-and-groove cooling structure, thereby making the inner two-channel airflow form a cooling air film that flows along the downstream profile of the small bend outlet end, so as to cool the small bend outlet section and the upper edge plate 401 of the gas turbine guide 40.

[0037] In the combustion chamber outlet cooling structure of the present invention, it has been calculated that under the maximum thermal state, the wall temperature of the inner ring of the flame tube can reach up to about 1000°C, and the local average stress is more than 200 MPa. The inner ring of the flame tube is a large-diameter thin-walled part with a limited stress resistance level. Therefore, in the cooling structure of the present invention, the starting section of the small bend pipe 10 located at the air inlet end of the small bend pipe 10 is directly inserted into the bird's beak ring cavity of the inner ring bird's beak ring 20, and is not designed as an integral part with the inner ring bird's beak ring 20. That is, the small bend pipe 10 and the inner ring of the flame tube are designed as a separate body in the present invention, which is not only conducive to assembly, but also can ensure the release of expansion stress in the hot state, so that the inner ring wall of the flame tube is not deformed by heat and causes other faults or safety accidents, and solves the problem of "small thermal stress release space, which may eventually lead to a flame with a thin wall" in the existing structure. The technical problem of "arching and deformation of the inner ring of the flame tube" is solved; in the cooling structure of the present invention, the upper edge plate support ring 106 used as the upper edge plate support plate of the gas turbine guide 40 is an integral part with the small bend pipe 10, and the integral forging machine is formed to reduce the number of parts and reduce the difficulty of assembling the gas turbine guide 40; in the cooling structure of the present invention, a tongue-and-groove cooling structure is also added at the outlet of the small bend pipe. Compared with ordinary divergent cooling, the cooling air film at the outlet of the tongue-and-groove cooling structure has a long coverage distance along the flow direction and a large air film thickness, which can effectively reduce the near-wall gas temperature of the outlet section of the small bend pipe to a certain extent, thereby reducing the heat load of the upper edge plate 401 of the gas turbine guide 40; the cooling structure of the present invention has been tested for combustion chamber components, whole machine bench tests and field test flights, and the effect is good.

[0038] Alternatively, if Figure 1 , Figure 6-7 As shown, a plurality of impact holes 201 are arranged in sequence and spaced apart in the circumferential direction of the inner ring bird beak ring 20. The plurality of impact holes 201 have the same diameter and are arranged in sequence and spaced apart in the circumferential direction, as shown in FIG. Figure 7 Alternatively, the multiple impact holes 201 have different diameters and are evenly spaced in sequence along the circumferential direction, as shown in FIG. Figure 6 In actual design, multiple heads are arranged in the circumferential direction of the combustion chamber, and the wall temperature of the small bend facing the head of the flame tube is significantly higher than the wall temperature of other positions between the heads. Based on this, in this optional solution, while meeting the pressure loss of the combustion chamber, the impact holes 201 on the inner ring of the flame tube are arranged in a sparse and dense manner, as shown in FIG. Figure 7 As shown, or arranged in an alternating manner, such as Figure 6 As shown, the small curved tube 10 facing the flame tube head can be arranged with impact holes 201 with larger apertures or compact arrangements, and vice versa, to better meet cooling requirements.

[0039] Alternatively, if Figure 1 and Figure 8As shown, there is an axial gap δ between the starting section of the small bend pipe and the bottom of the bird's beak ring cavity, 0.5mm≤δ≤3.5mm; in actual design, δ should meet the requirements of the dimension chain calculation, and ensure that the small bend pipe 10 and the inner ring of the flame tube do not interfere with each other in both cold and hot states, ensure the release of expansion stress in the hot state, and prevent the inner ring wall of the flame tube from being deformed by heat and causing other faults or safety accidents.

[0040] Alternatively, if Figure 1 and Figure 8 As shown, there is a radial gap θ between the inner ring surface of the starting section of the small bend pipe and the inner ring surface of the bird's beak ring cavity, 0.07mm≤θ≤0.15mm; in this optional scheme, the small gap θ formed between the inner ring surface of the starting section of the small bend pipe and the inner ring surface of the bird's beak ring cavity not only meets the assembly requirements, but also ensures that the flame tube does not leak in the hot state.

[0041] Alternatively, if Figure 1 and Figure 8 As shown, there is a radial gap D between the outer ring surface of the starting section of the small bend and the outer ring surface of the bird's beak ring cavity, and an axial gap L is provided between the cavity bottom of the bird's beak ring cavity and the end surface of the outer ring of the inner ring bird's beak ring 20, and D / L=0.1~0.2, and the angle α between the center line of the impact hole 201 and the outer ring surface of the bird's beak ring cavity is related to D / L, the larger the D / L is, the larger the angle α is to 90°, and the smaller the D / L is, the smaller the angle α is to be greater than 0°.

[0042] Alternatively, if Figure 1 , Figure 9-10 As shown, each circle of the divergent hole group includes a plurality of divergent holes 102 arranged in sequence along the circumferential direction, and the plurality of divergent holes 102 of the two adjacent circles of the divergent hole group are staggered one by one in the circumferential direction, that is, the positions of the two adjacent circles are staggered from each other in the circumferential direction to form a rhombus arrangement. The tangential angle of the divergent holes 102 of the remaining circles of the divergent hole group except the innermost circle is 80°~100°, and the punching angle is 20°~30°. In the existing conventional method, the small bend pipe adopts a conventional air film + divergent cooling structure. Due to its special convex surface with a large curvature profile structure, it is extremely unfavorable for the cooling air film to adhere to the wall. In the cooling structure of the present invention, the divergent holes 102 of the remaining circles of the divergent hole group except the innermost circle all adopt a large angle (tangential angle of 80°~100°) compound angle (each divergent hole 102 has a tangential angle and a punching angle), which can greatly improve the air film wall adhesion effect. The tangential angle of the diverging holes 102 of the innermost circle of the diverging hole group is greater than 0° to 15°, and the punching angle is less than 30°.

[0043] In this option, if Figure 9-10 As shown, three rows of divergent holes 102 are arranged on the arc surface of the middle section of the small bend pipe, each row is arranged with small holes of 210×φ0.5, and the circumferential positions of two adjacent rows are staggered to form a rhombus arrangement, such as Figure 5As shown. The first two rows are selected to have tangential openings. The tangential angle of the first row of holes is 80° to 90°, preferably 86°, and the tangential angle of the second row of holes is 90° to 100°, preferably 92°. The opening direction is toward the same side, that is, toward the direction of the rotating airflow. The punching angles of the first two rows of holes are both 20° to 30°, preferably 25°. Thus, through the design of the larger tangential angle of the divergent hole 102 and the composite angle in two directions, the inner two channel airflows can form a large air film cooling at the large curvature in the middle section of the small bend, thereby better protecting the metal substrate of the small bend 10. The third row of divergent holes are punched along the airflow direction at 0° to 15° (excluding the tangential angle of 0°), and the punching angle is preferably less than 30° to ensure the formation of a more tightly adherent wall-adherent airflow to avoid flow to protect the metal substrate of the small bend 10.

[0044] Alternatively, if Figure 1 As shown, the outlet section of the small bend pipe is concavely extended to form an annular air film groove, and an annular tongue ring 104 and a tail ring are located on both sides of the air film groove. The air film groove and the tongue ring 104 form a tongue-groove cooling structure. The air film groove hole 103 is opened on the tail ring and communicates with the air film groove to introduce part of the two inner channel airflows into the impact tongue ring 104, thereby forming a cooling air film that flows along the profile of the outlet section of the small bend pipe and adheres to the wall.

[0045] In this option, if Figure 1 As shown, there are multiple air film slots 103, and the multiple air film slots 103 are evenly spaced along the circumferential direction. The height of the air film slot is 1mm to 2mm; preferably, the height of the air film slot is 1.5mm. During operation, the airflow passes through the air film slots 103 and impacts the tongue ring 104, so that a cooling air film flowing along the downstream profile of the small elbow outlet section is formed, which cools the gas turbine guide vane and further reduces the tip temperature.

[0046] Preferably, if Figure 8 As shown, the inner ring of the starting section of the small bend pipe is provided with a chamfer, which is conducive to guiding the small bend pipe 10 for assembly. Figure 1 As shown, a thermal barrier coating 101 is sprayed on the gas side profile of the small elbow 10 to improve its heat resistance.

[0047] Alternatively, if Figure 1As shown, the gas turbine guide vane 40 includes guide vanes arranged in sequence along the circumferential direction, and the guide vanes include a blade body 402 and an upper edge plate 401, and the upper edge plate 401 is arranged at intervals corresponding to the upper edge plate support ring 106. The upper edge plate support ring 106 is provided with support ring holes 108 arranged in sequence along the circumferential direction and penetrated therethrough, so as to introduce part of the two inner channel airflows through the support ring holes 108 and the upper edge plate 401 into the blade body 402. The combustion chamber outlet cooling structure also includes a large bend pipe 30 arranged at intervals outside the small bend pipe 10, and the flange edge of the large bend pipe 30 is provided with flange edge holes 301 arranged in sequence along the circumferential direction and penetrated therethrough, so as to introduce the airflow 50 outside the large bend pipe into the gas turbine guide vane 40 and the blade body 402 through the flange edge holes 301.

[0048] The cooling structure of the present invention further includes a support ring hole 108 opened on the upper edge plate support ring 106, and the support ring hole 108 is used to introduce part of the two inner channel airflows into the blade body 402 of the gas turbine guide 40 through the support ring hole 108. After the airflow enters the blade body 402, it flows along the holes densely distributed on both sides to cool the blade body 402, thereby reducing the probability of failures such as ablation and cracks caused by the high-temperature combustion gas scouring the blade body 402; further, the cooling structure further includes a flange side hole 301 opened on the flange side of the large bend pipe 30, and the gas outside the large bend pipe is cooled. The flow 50 enters the turbine through the flange side hole 301, a part of it cools the blade body 402 and then flows into the main channel, and the other part enters other parts for sealing cooling. Therefore, in the cooling structure of the present invention, through the cooperation of the impact hole 201, the diverging hole 102, the air film slot hole 103, the tongue ring 104, the branch ring hole 108 and the flange side hole 301, the two inner channel airflows and the outer airflow 50 of the large bend pipe are introduced to cool the small bend pipe 10 and the gas turbine guide 40, and the cooling effect of both is good, and it is not easy to cause ablation and cracks due to the scouring of high-temperature combustion gas.

[0049] Alternatively, if Figure 1 and Figure 3 As shown, the combustion chamber outlet cooling structure also includes a positioning pin 80, which is inserted into the upper edge plate 401 after being inserted through the upper edge plate support ring 106 to position the small bend pipe 10. In this optional solution, the small bend pipe 10 and the upper edge plate support ring 106 are designed as an integral part, and a pin hole 105 is provided in the circumference of the upper edge plate support ring 106. The positioning pin 80 can be used to fix the small bend pipe 10 and the gas turbine guide 40, that is, the small bend pipe 10 is positioned, and the positioning pin 80 is cleverly used to connect the small bend pipe 10 and the gas turbine guide 40 together. Compared with other connection methods, this method has a simple structure, a small number of parts, is economical and reliable, is simple and reliable to assemble, and is convenient to assemble and disassemble, thereby improving the level of combined design.

[0050] Alternatively, if Figure 1 and Figure 2As shown, the support ring holes 108 and the flange side holes 301 are evenly spaced along the circumferential direction, and the number of the two is proportional to the number of the guide vanes, that is, the support ring holes 108 and the flange side holes 301 are evenly arranged corresponding to the guide vanes, and the internal two-channel airflow is used to cool the gas turbine guide vanes, thereby improving the cooling effect of the guide vanes.

[0051] Preferably, if Figure 1 and Figure 4 As shown, the radial end surface of the outlet end of the upper edge plate support ring 106 is concave to form a mounting ring groove, and the inner ring of the mounting ring groove is opened in sequence along the circumferential direction to form a boss 107. The combustion chamber outlet cooling structure also includes a special-shaped sealing ring 90 clamped in the mounting ring groove, and the special-shaped sealing ring 90 is used to seal the radial gap between the outlet end of the upper edge plate support ring 106 and the outlet side of the upper edge plate 401. In this preferred embodiment, due to the circumferential opening on the inner ring inside the mounting ring groove, it is convenient to remove the special-shaped sealing ring 90 from the mounting ring groove, and it is also convenient to install the special-shaped sealing ring 90, and the operation is simple.

[0052] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A combustion chamber outlet cooling structure, comprising an inner ring bird beak ring (20) at the rear of the inner ring of the flame tube, a small curved pipe (10) with a single wall, and a gas turbine guide (40), characterized in that: The starting section of the small bend pipe located at the air inlet end of the small bend pipe (10) is inserted into the inner beak ring (20) through the opening of the inner beak ring (20), and the inner beak ring (20) is provided with an impact hole (201) for introducing part of the two inner channel air flows into the combustion chamber outlet flow channel (70) after passing through the impact hole (201) and the beak ring cavity of the inner beak ring (20), so as to form a wall-attached cooling air film in the combustion chamber outlet flow channel (70) to cover the starting section of the small bend pipe; A plurality of radially spaced diverging hole groups are provided on the middle section of the small curved tube (10) so as to be used for introducing part of the two inner channel air flows into the combustion chamber outlet flow channel (70) through the plurality of radially spaced diverging hole groups, so as to form a large cooling air film at the large curvature of the middle section of the small curved tube; A tongue-and-groove cooling structure and an air film slot hole (103) are provided on the outlet section of the small bend pipe (10) at the exhaust end of the small bend pipe, so as to introduce part of the two inner channel airflows into the impact tongue-and-groove cooling structure through the air film slot hole (103), so as to form a cooling air film flowing along the profile of the outlet section of the small bend pipe and adhering to the wall, so as to cool the outlet section of the small bend pipe and the upper edge plate (401) of the gas turbine guide vane (40); The small bend pipe (10) also includes an annular upper edge plate support ring (106) located behind the outlet section of the small bend pipe. The gas turbine guide (40) is arranged at the exhaust end of the small bend pipe (10) and is located inside the upper edge plate support ring (106).

2. The combustion chamber outlet cooling structure according to claim 1, characterized in that: A plurality of impact holes (201) are arranged in sequence and at intervals on the circumference of the inner bird beak ring (20); The plurality of impact holes (201) have the same diameter and are arranged in a sparse and dense manner in the circumferential direction; or The plurality of impact holes (201) have different diameters and are evenly spaced and arranged in sequence along the circumferential direction.

3. The combustion chamber outlet cooling structure according to claim 1, characterized in that: There is an axial gap δ between the starting section of the small bend and the bottom of the bird's beak ring cavity, 0.5mm≤δ≤3.5mm; There is a radial gap θ between the inner annular surface of the starting section of the small bend pipe and the inner annular surface of the bird's beak annular cavity, 0.07mm≤θ≤0.15mm; There is a radial gap D between the outer ring surface of the starting section of the small bend and the outer ring surface of the bird's beak ring cavity, and there is an axial gap L between the cavity bottom of the bird's beak ring cavity and the end surface of the outer ring of the inner ring bird's beak ring (20), and D / L=0.1-0.2, and the angle α between the center line of the impact hole (201) and the outer ring surface of the bird's beak ring cavity is related to D / L, the larger the D / L, the larger the angle α is to 90°, and the smaller the D / L is, the smaller the angle α is to be greater than 0°.

4. The combustion chamber outlet cooling structure according to claim 1, characterized in that: Each circle of diverging hole groups comprises a plurality of diverging holes (102) arranged in sequence and at intervals along the circumferential direction, and the plurality of diverging holes (102) of two adjacent circles of diverging hole groups are arranged one by one in a staggered manner in the circumferential direction; The tangential angle of the diverging holes (102) of the diverging hole groups of the remaining circles except the innermost circle is 80° to 100°, and the punching angle is 20° to 30°; The tangential angle of the divergent holes (102) in the innermost divergent hole group is greater than 0° to 15°, and the punching angle is less than 30°.

5. The combustion chamber outlet cooling structure according to claim 1, characterized in that: The outlet section of the small curved pipe is concavely extended to form an annular air film groove, and an annular tongue ring (104) and a tail ring are located on both sides of the air film groove; The air film groove and the tongue ring (104) form a tongue-and-groove cooling structure; The air film slot hole (103) is formed on the tail ring and is connected to the air film slot to introduce part of the two inner channel airflows into the impact tongue ring (104), thereby forming a cooling air film that flows along the wall of the outlet section of the small bend.

6. The combustion chamber outlet cooling structure according to claim 5, characterized in that: There are a plurality of air film slots (103), and the plurality of air film slots (103) are evenly spaced along the circumferential direction; The height of the air film groove is 1mm to 2mm.

7. The combustion chamber outlet cooling structure according to claim 1, characterized in that: The inner ring of the starting section of the small elbow is provided with a chamfer; A thermal barrier coating (101) is also sprayed on the gas side profile of the small elbow (10).

8. The combustion chamber outlet cooling structure according to claim 1, characterized in that: The gas turbine guide vane (40) comprises guide vane blades arranged in sequence along the circumferential direction, the guide vane comprising a blade body (402) and an upper edge plate (401), and the upper edge plate (401) is arranged at intervals corresponding to the upper edge plate support ring (106); The upper edge plate support ring (106) is provided with support ring holes (108) arranged in sequence along the circumferential direction and penetrating therethrough, so as to introduce part of the two inner channel air flows into the blade body (402) after passing through the support ring holes (108) and the upper edge plate (401); The combustion chamber outlet cooling structure also includes a large curved pipe (30) arranged at intervals outside the small curved pipe (10), and flange edge holes (301) arranged in sequence along the circumferential direction and penetrating therethrough are opened on the flange edge of the large curved pipe (30), so as to guide the airflow (50) outside the large curved pipe through the flange edge holes (301) into the gas turbine guide vane (40) and the blade body (402).

9. The combustion chamber outlet cooling structure according to claim 8, characterized in that: The combustion chamber outlet cooling structure also includes a positioning pin (80), which is inserted into the upper edge plate (401) after being inserted through the upper edge plate support ring (106) to position the small curved pipe (10); The support ring holes (108) and the flange side holes (301) are arranged at even intervals along the circumferential direction, and the number of the two is proportional to the number of the guide vanes.

10. The combustion chamber outlet cooling structure according to claim 1, characterized in that: The radial end surface of the outlet end of the upper edge plate support ring (106) is concave to form a mounting ring groove, and the inner ring of the mounting ring groove is opened in sequence along the circumferential direction to form a boss (107); The combustion chamber outlet cooling structure also includes a special-shaped sealing ring (90) clamped in the mounting ring groove, and the special-shaped sealing ring (90) is used to seal the radial gap between the outlet end of the upper edge plate support ring (106) and the outlet side of the upper edge plate (401).

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