A swirl heat shield cooling structure and method for a gas turbine combustor

Abstract

The application relates to a rotating flow heat-insulating cooling structure and a cooling method of a gas turbine combustion chamber, and belongs to the technical field of combustion chamber design. The structure comprises coaxial combustion chamber outer and inner shells, a nozzle mounting ring, a nozzle ring, a heat-insulating plate and a plurality of rotating flow supporting blocks. A secondary air channel is formed between the outer and inner shells. The heat-insulating plate is arranged between the inner shell and the nozzle ring and encloses a cooling cavity. The rotating flow supporting blocks have radial supporting and rotating flow guiding functions. The heat-insulating plate is provided with mixing holes which are connected with the cooling cavity and the main flow channel. The cooling method divides the secondary air into two parts, realizes cooling through a first mixing hole group, rotating flow cooling, a second mixing hole group and a third mixing hole group. The application realizes the synergistic effect of physical isolation, rotating flow enhanced heat exchange and staged mixing, reduces the heat load of the nozzle ring and the turbine inlet, and prolongs the service life of the hot end components.

Description

Technical Field

[0001] This invention relates to the technical field of combustion chamber design, and in particular to a swirling heat insulation cooling structure and cooling method for a gas turbine combustion chamber. Background Technology

[0002] As gas turbine technology continues to develop towards higher power density and higher combustion temperatures, more stringent requirements are being placed on the high-temperature resistance and cooling performance of key hot-end components downstream of the combustion chamber. To improve the uniformity of the combustion chamber outlet gas and reduce the heat load, existing gas turbines typically employ structures such as transition sections or nozzle rings between the combustion chamber outlet and the turbine inlet to guide the high-temperature gas smoothly into the turbine.

[0003] However, in the relevant technologies, there is no special heat insulation and cooling structure for the nozzle ring surface in the combustion chamber. The high-temperature gas flows directly along the nozzle ring surface and enters the turbine, causing the nozzle ring to be exposed to an extreme high-temperature environment for a long time, which is prone to severe high-temperature oxidation. At the same time, the turbine blades will undergo slow and irreversible creep deformation under the coupling effect of high speed and high temperature. As the operating time accumulates, the blades elongate and twist. When the deformation exceeds the design clearance, it will cause friction and collision with the casing, and even cause catastrophic consequences such as shutdown.

[0004] Therefore, how to effectively reduce the heat load at the nozzle ring and turbine inlet, and suppress high-temperature oxidation and creep damage, has become an urgent technical problem to be solved. Summary of the Invention

[0005] In response to the shortcomings of the existing production technology, the applicant provides a swirling heat insulation cooling structure and cooling method for a gas turbine combustion chamber. This structure reduces the heat load on the nozzle ring and turbine inlet and extends the service life of hot-end components through the synergistic effect of physical isolation, enhanced heat transfer by swirling flow, and staged mixing cooling.

[0006] The technical solution adopted in this invention is as follows: This invention provides a swirl-flow heat insulation and cooling structure for a gas turbine combustion chamber, the structure including a combustion chamber outer shell, a combustion chamber inner shell, a nozzle mounting ring, a nozzle ring, a heat insulation plate, and multiple swirl support blocks; The nozzle mounting ring is fixed to the front end of the combustion chamber. The outer shell of the combustion chamber and the inner shell of the combustion chamber are coaxially arranged. The front ends of the outer shell of the combustion chamber and the inner shell of the combustion chamber are fixedly connected to the nozzle mounting ring, forming a secondary air channel between the outer shell of the combustion chamber and the inner shell of the combustion chamber. The nozzle ring is fixed to the rear end of the combustion chamber; the heat insulation plate is coaxially disposed between the inner shell of the combustion chamber and the nozzle ring, the outer wall surface of the heat insulation plate is connected to the main flow channel of the combustion chamber, and the inner wall surface of the heat insulation plate and the nozzle ring enclose an independent cooling chamber, which is connected to the secondary air channel; The plurality of swirling support blocks are arranged obliquely in the circumferential direction and are spaced apart between the combustion chamber shell and the nozzle ring. One end of the swirling support block is fixedly connected to the rear end of the combustion chamber shell and the other end is fixedly connected to the front end of the nozzle ring. The swirling support block is configured to simultaneously provide radial support to the nozzle ring and guide the secondary air in a swirling manner, so that the secondary air enters the cooling chamber in a swirling manner. The heat insulation plate has multiple mixing holes that connect the cooling chamber and the main flow channel of the combustion chamber. This allows part of the secondary air entering the cooling chamber to undergo convective heat exchange along the inner wall of the heat insulation plate, while the other part enters the main flow channel of the combustion chamber through the mixing holes to mix with the high-temperature fuel gas for cooling.

[0007] Its beneficial effects are as follows: The heat insulation plate physically isolates the high-temperature combustion gas from the nozzle ring, fundamentally preventing the high-temperature combustion gas from directly eroding the nozzle ring surface and reducing the risk of high-temperature oxidation of the nozzle ring; the swirling support block integrates radial support and swirling guidance, solving the nozzle ring fixing problem and extending the residence time of secondary air in the cooling chamber through swirling air, thus enhancing the convective heat transfer effect of the inner wall of the heat insulation plate; the construction of a cooling system combining cooling chamber heat exchange with mixing hole cooling enables the cascade utilization of secondary air, improving energy utilization while ensuring cooling effect, reducing the nozzle ring surface temperature, and extending the service life of the nozzle ring and turbine blades.

[0008] As a further improvement, the heat insulation plate includes a cylindrical part, a transition part, and an annular part connected coaxially in sequence, wherein the transition part is arc-shaped; The cylindrical body portion is disposed near the inner shell of the combustion chamber, and the annular body portion is disposed near the nozzle ring; The ring portion extends toward one side of the nozzle ring to form an annular connecting portion that mates with the nozzle ring; The cylindrical part is provided with a second group of mixing holes evenly distributed in the circumferential direction, and the connecting part is provided with a third group of mixing holes evenly distributed in the circumferential direction. The second group of mixing holes and the third group of mixing holes together constitute the plurality of mixing holes. The second mixing hole group is located at one end of the cylinder near the inner shell of the combustion chamber, and is used to release some of the air in the cooling chamber in advance to form a mixing and cooling effect close to the wall at the front end of the heat insulation plate; the third mixing hole group is located at one end of the connecting part near the nozzle ring, and is used to release the remaining air before the inlet end of the nozzle ring to mix and cool the gas entering the nozzle ring.

[0009] Its beneficial effects are as follows: the arc-shaped transition section can effectively alleviate the stress concentration of the heat insulation plate under high-temperature alternating load, avoid thermal fatigue cracking, and improve structural reliability; the mixing holes are divided into two groups of axially distributed holes, which realizes the staged release of cooling air. The second mixing hole group releases some air in advance, forming a low-temperature gas film close to the wall at the front end of the heat insulation plate, which prevents the high-temperature gas from directly contacting the outer wall of the heat insulation plate; the third mixing hole group releases the remaining air before the nozzle ring inlet, which performs final mixing and cooling of the gas that is about to enter the nozzle ring, further reducing the turbine inlet gas temperature, while ensuring the uniformity of gas temperature.

[0010] As a further improvement, the swirl support block includes a cylindrical support body, with a first tip at the upstream end of the airflow and a second tip at the downstream end of the airflow; the plurality of swirl support blocks are tilted in the same direction relative to the combustion chamber axis.

[0011] Its beneficial effects are as follows: the pointed ends at both ends can significantly reduce the flow loss caused by upstream airflow collision and downstream airflow separation, reduce the pressure loss of secondary air, and improve the utilization rate of cooling air; all swirling support blocks are arranged in the same direction with an inclined arrangement, which can form a uniform and stable circumferential swirling flow field in the cooling cavity, avoid the generation of local eddies or dead zones, make the heat exchange of the inner wall of the heat insulation plate more uniform, and prevent local overheating.

[0012] Furthermore, the cross-section of the swirl support block is any one of the following: elliptical cylinder, teardrop shape, airfoil, rhombus, or spindle shape.

[0013] Its beneficial effects are as follows: the above-mentioned streamlined cross-section can further optimize the aerodynamic performance, reduce airflow resistance, enhance the swirling guiding effect, increase the swirling intensity of secondary air, and thus improve the convective heat transfer efficiency of the cooling chamber; the selection of various cross-sectional shapes can adapt to the spatial size and airflow parameter requirements of different combustion chambers, improving the versatility and adaptability of the structure.

[0014] As a further improvement, the rear end of the combustion chamber shell is provided with a first mixing hole group evenly distributed in the circumferential direction, the first mixing hole group connecting the secondary air passage and the main air passage of the combustion chamber.

[0015] Its beneficial effects are as follows: by introducing a portion of secondary air directly into the main flow channel of the combustion chamber through the first mixing hole group, the first-stage mixing and cooling of the high-temperature gas is achieved, thereby reducing the overall temperature of the gas in advance and reducing the heat load on the subsequent heat insulation plate and nozzle ring; in conjunction with the two-stage mixing holes on the heat insulation plate, a total of three-stage mixing and cooling system is formed, which can achieve a gradient reduction in gas temperature and also avoid the problem of unstable combustion that is easily caused by excessive mixing in a single operation.

[0016] Furthermore, each of the swirl support blocks is circumferentially offset from the first mixing hole in the adjacent first mixing hole group.

[0017] Its beneficial effects are: it can effectively prevent secondary air from directly short-circuiting into the cooling chamber after flowing out of the first mixing hole, ensuring that the secondary air entering the cooling chamber has sufficient flow rate and pressure to ensure the swirling cooling effect; at the same time, it makes the secondary air more evenly distributed in the secondary air channel, improving the mixing uniformity of the first mixing hole group.

[0018] As a further improvement, the top of both sides of the nozzle ring blades is provided with an axial slot structure, and the rear end of the combustion chamber shell and the annular connecting part of the heat insulation plate are respectively inserted into the corresponding slot structure and fixedly connected.

[0019] Its advantages are: the axial slot structure enables rapid positioning and assembly of the combustion chamber shell, heat shield and nozzle ring, improving installation efficiency.

[0020] The present invention also provides a cooling method for a gas turbine combustion chamber, employing the swirling heat insulation cooling structure described in any of the above claims, comprising the following steps: S1. The secondary air in the secondary air passage is divided into a first branch and a second branch. The first branch enters the main channel of the combustion chamber through the first mixing hole group on the inner shell of the combustion chamber and performs first-stage mixing and cooling with the high-temperature gas. S2. After being guided by multiple swirl support blocks arranged in the same direction, the second branch forms a swirling flow field that rotates in the circumferential direction and enters the cooling cavity between the heat insulation plate and the nozzle ring. The swirling air flows spirally along the inner wall of the heat insulation plate and undergoes forced convection heat transfer, while simultaneously providing radiative heat insulation and convective cooling to the nozzle ring. S3. The secondary air that has completed heat exchange in the cooling chamber enters the main flow channel of the combustion chamber through multiple mixing holes on the heat insulation plate, and undergoes a second stage of mixing and cooling with the fuel gas after the first stage of mixing and cooling. S4. After being mixed and cooled in two stages, the gas flows into the turbine after being rectified by the nozzle ring and expands to do work.

[0021] Its beneficial effects are as follows: by controlling the flow of secondary air, an orderly cooling process is achieved, which first mixes and cools, then swirls and cools, and then mixes and cools again, taking into account the needs of gas temperature control and cooling of hot-end components; during the swirl cooling process, the secondary air not only cools the heat insulation plate, but also indirectly cools the nozzle ring through thermal radiation and convection, realizing multiple uses of the air and improving the overall efficiency of the cooling system.

[0022] As a further improvement, in step S2, the pointed ends of the swirling support block at both ends reduce the flow loss caused by the collision of the upstream airflow and the flow separation of the downstream airflow, thereby improving the swirling intensity of the secondary air and the heat exchange efficiency of the cooling chamber.

[0023] Its beneficial effects are as follows: by optimizing the structure of the swirling support block, the swirling intensity and heat transfer coefficient of the cooling air are improved without increasing additional power consumption, thereby improving the heat transfer efficiency of the cooling chamber and further reducing the working temperature of the heat insulation plate and nozzle ring.

[0024] As a further improvement, in step S3, part of the secondary air in the cooling chamber enters the main channel through the second mixing hole group of the heat insulation plate cylinder, and another part enters the main channel through the third mixing hole group of the heat insulation plate annular connection, forming a multi-point graded mixing distributed along the axial direction.

[0025] Its beneficial effects are as follows: multi-point staged mixing can make the cooling air and high-temperature gas mix more fully, avoid local temperatures that are too high or too low, significantly improve the temperature uniformity of the gas at the combustion chamber outlet, and reduce the thermal stress of the turbine blades; at the same time, a continuous airflow is formed on the outer wall of the heat insulation plate, which further blocks the heat radiation and convective heat transfer of the high-temperature gas and extends the service life of the heat insulation plate. Attached Figure Description

[0026] Figure 1 This is a three-dimensional schematic diagram of the overall structure of the present invention.

[0027] Figure 2 This is a cross-sectional view of the internal structure of the present invention.

[0028] Figure 3 This is a schematic diagram of the structure of the heat insulation board of the present invention.

[0029] Figure 4 This is a schematic diagram of the swirl support block of the present invention.

[0030] The components include: 1. Nozzle mounting ring; 2. Combustion chamber outer shell; 3. Combustion chamber inner shell; 4. Heat insulation plate; 5. Nozzle ring; 6. Swirl support block; 31. First mixing pore group; 41. Ring body; 42. Cylindrical body; 43. Transition section; 44. Connecting section; 45. Second mixing hole group; 46. Third mixing hole group; 61. Support body; 62. First tip; 63. Second tip. Detailed Implementation

[0031] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. In the description of the present invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0032] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0033] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0034] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0035] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0036] like Figures 1 to 4 As shown, this embodiment provides a swirling heat insulation and cooling structure for a gas turbine combustion chamber, which mainly includes a nozzle mounting ring 1, a combustion chamber outer shell 2, a combustion chamber inner shell 3, a heat insulation plate 4, a nozzle ring 5, and multiple swirling support blocks 6.

[0037] In this embodiment, the nozzle mounting ring 1 is an integral annular structure, coaxially fixed to the front end of the combustion chamber; the front end face of the nozzle mounting ring 1 is uniformly provided with 12 circular holes along the circumference, the diameter of the circular holes is 100mm, and the central axis of the circular holes is parallel to the central axis of the combustion chamber and is equidistantly distributed.

[0038] In this embodiment, the combustion chamber outer shell 2 and the combustion chamber inner shell 3 are coaxially arranged, and the front end face of both is fixed to the rear end face of the nozzle mounting ring 1 by welding. The welding joint adopts continuous sealing welding to ensure airtightness. The inner diameter of the combustion chamber outer shell 2 is larger than the outer diameter of the combustion chamber inner shell 3. Furthermore, a first mixing hole group 31 is provided at the rear end of the combustion chamber shell 3 (the end away from the nozzle mounting ring 1). The first mixing hole group 31 includes a plurality of circular first mixing holes evenly distributed along the circumference of the combustion chamber shell 3. The diameter of the first mixing holes ranges from 8mm to 20mm, and the number of holes ranges from 12 to 36. In a preferred embodiment, the number of first mixing holes is 24, the diameter is 10mm, and the central axis of the first mixing holes is arranged radially along the combustion chamber shell 3, connecting the secondary air passage and the main combustion chamber passage.

[0039] In this embodiment, the nozzle ring 5 is coaxially fixed to the rear end of the combustion chamber and located upstream of the turbine. It is used to rectify the high-temperature gas and guide it to the turbine blades. The nozzle ring 5 includes an annular outer ring, an inner ring, and multiple guide blades connecting the outer ring and the inner ring. The guide blades are evenly distributed circumferentially. The top of both sides of the outer ring blades and the top of both sides of the inner ring blades of the nozzle ring 5 are provided with axially extending slot structures. The width of the slots is adapted to the wall thickness of the combustion chamber shell 2 and the wall thickness of the heat insulation plate 4.

[0040] In this embodiment, the heat insulation plate 4 is coaxially disposed between the inner shell 3 of the combustion chamber and the nozzle ring 5. The heat insulation plate 4 includes a cylindrical part 42, a transition part 43 and an annular part 41 connected coaxially in sequence. The cylindrical part 42 is disposed close to the inner shell 3 of the combustion chamber, the annular part 41 is disposed close to the nozzle ring 5, and the transition part 43 has an arc-shaped structure, which smoothly connects the rear end of the cylindrical part 42 and the front end of the annular part 41 to alleviate stress concentration under high temperature alternating load. Furthermore, the ring body portion 41 extends axially towards the side of the nozzle ring 5 to form an annular connecting portion 44. The outer diameter of the connecting portion 44 is adapted to the inner diameter of the slot of the inner ring of the nozzle ring 5. The connecting portion 44 is inserted into the slot of the inner ring of the nozzle ring 5 and fixedly connected by welding. The rear end of the combustion chamber shell 2 is inserted into the slot of the outer ring of the nozzle ring 5 and fixedly connected by spot welding. Furthermore, the front end of the cylindrical body 42 is fixed to the rear end of the inner shell 3 of the combustion chamber by welding, and the welding joint adopts continuous sealing welding; a second mixing hole group 45 is provided on the cylindrical body 42 near the inner shell 3 of the combustion chamber, and the second mixing hole group 45 includes a plurality of circular second mixing holes evenly distributed along the circumference of the cylindrical body 42; a third mixing hole group 46 is provided on the connecting part 44, and the third mixing hole group 46 includes a plurality of circular third mixing holes evenly distributed along the circumference of the connecting part 44; the diameter of the second mixing hole and the third mixing hole are both in the range of 1mm-3mm, and the number of holes is both in the range of 24-48; in a preferred embodiment, the number of the second mixing hole and the third mixing hole is 36, and the diameter of the hole is 2mm. The two together constitute a plurality of mixing holes on the heat insulation plate 4, connecting the cooling chamber and the main flow channel of the combustion chamber.

[0041] In this embodiment, the outer wall surface of the heat insulation plate 4 is in direct contact with the main flow channel of the combustion chamber, and the inner wall surface and the front end face of the nozzle ring 5 form an independent annular cooling chamber, and the front end of the cooling chamber is connected to the secondary air channel.

[0042] In this embodiment, multiple swirl support blocks 6 are spaced apart and evenly distributed circumferentially between the combustion chamber shell 3 and the nozzle ring 5, with a number ranging from 6 to 24; in a preferred embodiment, the number of swirl support blocks 6 is 12. The front end of each swirl support block 6 is welded and fixed to the rear end face of the combustion chamber shell 3, and the rear end is welded and fixed to the front end face of the inner ring of the nozzle ring 5, which is used to provide radial support for the nozzle ring 5 and prevent the nozzle ring 5 from undergoing radial deformation under high temperature and high pressure.

[0043] Furthermore, the swirl support block 6 includes a cylindrical support body 61. The upstream end (front end) of the support body 61 is integrally formed with a first tip 62, and the downstream end (rear end) of the airflow is integrally formed with a second tip 63. The tips of the first tip 62 and the second tip 63 face the airflow direction, which are used to reduce the flow loss caused by the collision of the upstream airflow and the flow separation of the downstream airflow, respectively, thereby improving the swirl intensity of the secondary air and the heat exchange efficiency of the cooling chamber.

[0044] All swirl support blocks 6 are arranged at an angle relative to the combustion chamber axis, with an inclination angle ranging from 15° to 45°, so that the secondary air flowing through the swirl support blocks 6 forms a swirling field that rotates in the circumferential direction. In practical applications, the cross-sectional shape of the swirl support block 6 can be any of the following: elliptical cylinder, teardrop shape, airfoil, rhombus, or shuttle shape, in order to optimize aerodynamic performance.

[0045] In this embodiment, each swirl support block 6 is circumferentially staggered with the first mixing hole in the adjacent first mixing hole group 31 to prevent secondary air from directly short-circuiting into the cooling chamber after flowing out of the first mixing hole, thus ensuring that the secondary air entering the cooling chamber has sufficient flow rate and pressure.

[0046] In addition, this embodiment also provides a cooling method for a gas turbine combustion chamber, which adopts the above-mentioned swirling heat insulation cooling structure, and the working process is as follows: When the combustion chamber is working, fuel and air burn at the front end of the combustion chamber to produce high-temperature gas. The high-temperature gas flows from the front end to the rear end along the main flow channel of the combustion chamber and flows along the outer wall of the heat insulation plate 4 to the nozzle ring 5. Secondary air (e.g., from an air compressor) enters the secondary air passage between the combustion chamber outer shell 2 and the combustion chamber inner shell 3, and is divided into a first branch and a second branch: Secondary air from the first branch is radially injected into the main flow channel of the combustion chamber through the first mixing hole group 31 on the inner shell 3 of the combustion chamber, and mixes with the high-temperature gas for the first stage of cooling, initially reducing the overall temperature of the gas and reducing the heat load on the subsequent heat insulation plate 4 and nozzle ring 5. The secondary air in the second branch continues to flow backward along the secondary air channel. When it passes through multiple swirl support blocks 6 arranged in the same direction and tilted, it is guided by the swirl support blocks 6 to form a swirling field that rotates in the circumferential direction. Then, it enters the cooling chamber between the heat insulation plate 4 and the nozzle ring 5 in a swirling manner. The swirling air flows spirally along the inner wall of the heat insulation plate 4 and undergoes forced convection heat exchange with the inner wall of the heat insulation plate 4, carrying away the heat absorbed by the heat insulation plate 4. At the same time, the low-temperature air in the cooling chamber cools the front end of the nozzle ring 5 through thermal radiation and convection, preventing the nozzle ring 5 from being directly exposed to the high-temperature combustion gas. After the secondary air temperature rises after heat exchange in the cooling chamber, it flows out of the cooling chamber in two parts: one part is radially injected into the main flow channel of the combustion chamber through the second mixing hole group 45 on the cylinder part 42 of the heat insulation plate 4, forming a low-temperature gas film close to the wall at the front end of the heat insulation plate 4, preventing direct contact between the high-temperature gas and the outer wall of the heat insulation plate 4, and at the same time, it undergoes the second stage of mixing and cooling with the gas after the first stage of mixing and cooling; the other part is radially injected into the main flow channel of the combustion chamber through the third mixing hole group 46 on the connecting part 44 of the heat insulation plate 4, and undergoes the second stage of mixing and cooling with the gas before the inlet end of the nozzle ring 5, further reducing the temperature of the gas entering the nozzle ring 5.

[0047] The uniformity of the gas temperature is improved after two-stage multi-point mixing and cooling. Then, after being rectified by nozzle ring 5, the gas flows into the turbine to expand and do work, driving the turbine to rotate.

[0048] This invention achieves physical isolation between high-temperature gas and nozzle ring 5 through heat insulation plate 4. Combined with the swirling support block 6 for enhanced heat exchange and a three-stage mixing and cooling system, it effectively reduces the heat load on nozzle ring 5 and turbine inlet, suppresses high-temperature oxidation of nozzle ring 5 and creep damage to turbine blades, and extends the service life of hot-end components.

[0049] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0050] The embodiments described above are merely illustrative of implementation methods of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A swirling heat insulation and cooling structure for a gas turbine combustion chamber, comprising a combustion chamber outer shell and a combustion chamber inner shell, characterized in that, Also includes: A nozzle mounting ring is fixed to the front end of the combustion chamber. The outer shell of the combustion chamber and the inner shell of the combustion chamber are coaxially arranged. The front ends of both the outer shell and the inner shell of the combustion chamber are fixedly connected to the nozzle mounting ring, forming a secondary air passage between the outer shell and the inner shell of the combustion chamber. The nozzle ring is fixed at the rear end of the combustion chamber; A heat insulation plate is coaxially disposed between the inner shell of the combustion chamber and the nozzle ring. The outer wall surface of the heat insulation plate is connected to the main flow channel of the combustion chamber, and the inner wall surface of the heat insulation plate and the nozzle ring enclose an independent cooling chamber. The cooling chamber is connected to the secondary air channel. A plurality of swirl support blocks are arranged obliquely in the circumferential direction and spaced apart between the combustion chamber shell and the nozzle ring. One end of each swirl support block is fixedly connected to the rear end of the combustion chamber shell and the other end is fixedly connected to the front end of the nozzle ring. The swirl support block is configured to simultaneously provide radial support to the nozzle ring and guide the secondary air in a swirling manner, so that the secondary air enters the cooling chamber in a swirling manner. The heat insulation plate has multiple mixing holes that connect the cooling chamber and the main flow channel of the combustion chamber. This allows part of the secondary air entering the cooling chamber to undergo convective heat exchange along the inner wall of the heat insulation plate, while the other part enters the main flow channel of the combustion chamber through the mixing holes to mix with the high-temperature fuel gas for cooling.

2. The swirling heat insulation and cooling structure for the gas turbine combustion chamber according to claim 1, characterized in that, The heat insulation plate includes a cylindrical part, a transition part and an annular part connected coaxially in sequence, wherein the transition part is arc-shaped; The cylindrical body portion is disposed near the inner shell of the combustion chamber, and the annular body portion is disposed near the nozzle ring; The ring portion extends toward one side of the nozzle ring to form an annular connecting portion that mates with the nozzle ring; The cylindrical part is provided with a second group of mixing holes evenly distributed in the circumferential direction, and the connecting part is provided with a third group of mixing holes evenly distributed in the circumferential direction. The second group of mixing holes and the third group of mixing holes together constitute the plurality of mixing holes. The second mixing hole group is located at one end of the cylinder near the inner shell of the combustion chamber, and is used to release some of the air in the cooling chamber in advance to form a mixing and cooling effect close to the wall at the front end of the heat insulation plate; the third mixing hole group is located at one end of the connecting part near the nozzle ring, and is used to release the remaining air before the inlet end of the nozzle ring to mix and cool the gas entering the nozzle ring.

3. The swirling heat insulation and cooling structure for the gas turbine combustion chamber according to claim 1, characterized in that, The swirl support block includes a cylindrical support body, with a first pointed end at the upstream end of the airflow and a second pointed end at the downstream end of the airflow. The multiple swirling support blocks are tilted in the same direction relative to the combustion chamber axis.

4. The swirling heat insulation and cooling structure for the gas turbine combustion chamber according to claim 3, characterized in that, The cross-section of the swirl support block can be any one of the following: elliptical cylinder, teardrop shape, airfoil, rhombus, or spindle shape.

5. The swirling heat insulation and cooling structure for the gas turbine combustion chamber according to claim 1, characterized in that, The rear end of the combustion chamber shell is provided with a first mixing hole group evenly distributed in the circumferential direction, and the first mixing hole group connects the secondary air passage and the combustion chamber main flow passage. The first mixing hole group is used to introduce a portion of secondary air into the main gas flow channel to form mixing and cooling.

6. The swirling heat insulation and cooling structure for the gas turbine combustion chamber according to claim 5, characterized in that, Each of the swirl support blocks is circumferentially staggered with the first mixing hole in the adjacent first mixing hole group to prevent secondary air from directly short-circuiting into the main flow channel of the combustion chamber.

7. The swirling heat insulation and cooling structure for the gas turbine combustion chamber according to claim 1, characterized in that, The top of both sides of the nozzle ring blades are provided with axial slot structures, and the rear end of the combustion chamber shell and the annular connecting part of the heat insulation plate are respectively inserted into the corresponding slot structures and fixedly connected.

8. A cooling method for a gas turbine combustion chamber, characterized in that, The swirling heat insulation cooling structure as described in any one of claims 1-7 includes the following steps: S1. The secondary air in the secondary air passage is divided into a first branch and a second branch. The first branch enters the main channel of the combustion chamber through the first mixing hole group on the inner shell of the combustion chamber and performs first-stage mixing and cooling with the high-temperature gas. S2. After being guided by multiple swirl support blocks arranged in the same direction, the second branch forms a swirling flow field that rotates in the circumferential direction and enters the cooling cavity between the heat insulation plate and the nozzle ring. The swirling air flows spirally along the inner wall of the heat insulation plate and undergoes forced convection heat transfer, while simultaneously providing radiative heat insulation and convective cooling to the nozzle ring. S3. The secondary air that has completed heat exchange in the cooling chamber enters the main flow channel of the combustion chamber through multiple mixing holes on the heat insulation plate, and undergoes a second stage of mixing and cooling with the fuel gas after the first stage of mixing and cooling. S4. After being mixed and cooled in two stages, the gas flows into the turbine after being rectified by the nozzle ring and expands to do work.

9. The cooling method for a gas turbine combustion chamber according to claim 8, characterized in that, In step S2, the pointed ends of the swirling support block at both ends reduce the flow loss caused by the collision of the upstream airflow and the flow separation of the downstream airflow, thereby improving the swirling intensity of the secondary air and the heat exchange efficiency of the cooling chamber.

10. The cooling method for a gas turbine combustion chamber according to claim 8, characterized in that, In step S3, part of the secondary air in the cooling chamber enters the main channel through the second mixing hole group of the heat insulation plate cylinder, and the other part enters the main channel through the third mixing hole group of the heat insulation plate annular connection, forming a multi-point graded mixing distributed along the axial direction.

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