Flange structure of outer casing of combustion chamber and combustion chamber

Abstract

The combustion chamber outer casing flange structure is installed on a combustion chamber outer casing, the rear end of the combustion chamber outer casing is connected with a turbine casing front flange, and the structure comprises a heat insulation layer which is arranged on the inner wall face of the rear end of the combustion chamber outer casing. A combustion chamber is also provided. According to the combustion chamber outer casing flange structure, the heat insulation layer is arranged on the inner wall face of the rear end of the combustion chamber outer casing, heat transfer from a flame tube to the outer casing is reduced, the temperature and the temperature gradient near the rear flange of the outer casing are reduced, then thermal stress near the rear flange is reduced, and the service life of the combustion chamber outer casing is prolonged.

Description

Technical Field

[0001] The utility model relates to the field of gas turbines, in particular to the field of combustion chamber casing connection structures. Background Art

[0002] The combustion chamber is one of the core components of the gas turbine. The outer casing of the combustion chamber mainly connects the pressure-bearing seal and provides an installation interface. It is connected to the compressor outer casing upstream and the turbine outer casing downstream. The outer casing of the combustion chamber is the main load-bearing structure of the combustion chamber, and plays a role in transmitting loads such as axial force and torque. The stress near the rear flange where the outer casing of the combustion chamber is connected to the outer casing of the turbine is relatively large, which affects the overall service life of the outer casing.

[0003] In view of this, it is necessary to propose a combustion chamber outer casing flange structure to improve the service life of the outer casing. Utility Model Content

[0004] One purpose of the utility model is to provide a combustion chamber outer casing flange structure, which can improve the stress at the outer casing rear flange and increase the service life of the outer casing.

[0005] To achieve the above purpose, a combustion chamber outer casing flange structure is installed on the combustion chamber outer casing, the rear end of the combustion chamber outer casing is connected to the turbine casing front flange, and the structure includes a heat insulation layer arranged on the rear end inner wall surface of the combustion chamber outer casing.

[0006] In one or more embodiments, the combustion outer casing includes a first axial segment and a first radial segment, the turbine casing front flange includes a second axial segment and a second radial segment, the thermal insulation layer includes a third axial segment and a third radial segment, the third axial segment is arranged on the first axial segment, the third radial segment is arranged on the first radial segment, and is arranged to have a gap with the second radial segment.

[0007] In one or more embodiments, the third radial segment is fastened to the first radial segment via a connecting member.

[0008] In one or more embodiments, the first radial segment and the second radial segment are located radially outside the third radial segment and are fastened together via a connecting member.

[0009] In one or more embodiments, an outer wall surface of the outer casing of the combustion chamber is further provided with a thermal insulation blanket.

[0010] In one or more embodiments, the front end face of the thermal insulation layer is upstream of the rear end face of the thermal insulation blanket.

[0011] In one or more embodiments, the combustion chamber outer casing is further provided with a root thickened section, and the root thickened section is located downstream of the thermal insulation blanket.

[0012] In one or more embodiments, the thermal insulation layer is a ceramic-based composite material or a porous material.

[0013] In one or more embodiments, the thermal insulation layer is an annular thermal insulation layer.

[0014] Another object of the utility model is to provide a combustion chamber, which comprises the above combustion chamber outer casing flange structure.

[0015] The above-mentioned combustion chamber outer casing flange structure arranges a thermal insulation layer on the inner wall surface of the rear end of the combustion chamber outer casing, thereby reducing the heat transfer from the flame tube to the outer casing, reducing the temperature and temperature gradient near the rear flange of the outer casing, thereby reducing the thermal stress near the rear flange and extending the service life of the combustion chamber outer casing. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The above and other features, properties and advantages of the present invention will become more apparent through the following description in conjunction with the accompanying drawings and embodiments, in which:

[0017] Figure 1 It is a schematic diagram of the structure of a gas turbine;

[0018] Figure 2 It is a schematic diagram of the structure of the combustion chamber;

[0019] Figure 3 It is a schematic diagram of the combustion chamber outer casing flange structure. DETAILED DESCRIPTION

[0020] The present invention is further described below in conjunction with specific embodiments and drawings. More details are elaborated in the following description to facilitate a full understanding of the present invention. However, the present invention can obviously be implemented in a variety of other ways different from the description. Those skilled in the art can make similar generalizations and deductions based on actual application situations without violating the connotation of the present invention. Therefore, the protection scope of the present invention should not be limited by the content of this specific embodiment.

[0021] It should be noted that these and other subsequent drawings are only examples and are not drawn in proportion, and should not be used as a limitation on the actual scope of protection required by the present utility model.

[0022] Figure 1 The basic structure of the gas turbine is shown, including an air inlet 1, a fan 2, a planetary gearbox 3, a low-pressure compressor 4, a high-pressure compressor 5, a combustion chamber 6, a high-pressure turbine 7, a low-pressure turbine 8, a low-speed shaft 9, and a high-speed shaft 10. Atmosphere 101 enters from the air inlet 1 and forms an external airflow 102 and an internal airflow 103.

[0023] Figure 2The basic structure of the combustion chamber 6 is shown, including a combustion chamber outer casing 61, a diffuser 62, a combustion chamber outer casing 63, a fuel nozzle 64, a thermal insulation blanket 65, a head transition section 66, a flame tube outer ring 67, and a flame tube inner ring 68. The combustion chamber 6 is used to mix high-temperature and high-pressure gas and fuel and burn them to achieve the purpose of heating and pressurization. Since the combustion is organized in the combustion chamber, the temperature inside the combustion chamber is very high (the highest point can reach about 2000K), while the temperature outside the combustion chamber is relatively low, so the combustion chamber outer casing 61 has a large internal and external temperature difference. The upstream of the combustion chamber outer casing 61 ( Figure 2 The left side of the center) is connected to the compressor outer casing, and the downstream ( Figure 2 The turbine casing front flange 701 is connected to the turbine casing front flange 701 (center right side).

[0024] The stress near the rear flange of the outer casing is large, mainly due to the following reasons: (1) The part where the high-temperature and high-pressure gas and fuel are mixed and burned is located in the flame tube, and the flame tube 60 is located in the rear half of the outer casing 61. The heat convection and heat radiation of the flame tube cause the temperature of the rear half of the outer casing to be much higher than that of the front half of the outer casing 61, and the working conditions are even worse; (2) In order to reduce the temperature gradient between the inside and outside of the outer casing, an insulation blanket 65 is designed in the outer casing body section for heat preservation. However, it is not convenient to arrange an insulation blanket at the rear end A flange because connecting bolts need to be arranged. This results in a large temperature gradient near the rear flange, which in turn leads to large thermal stress near the rear flange; (3) The temperature of the rear flange of the combustion chamber outer casing is relatively high, while the temperature of the front flange of the turbine outer casing connected to it is relatively low. The two are fixed together by bolts, so there will be problems with thermal deformation inconsistency, which will bring considerable stress; (4) The combustion chamber outer casing 61 is the main load-bearing structure of the combustion chamber, which plays the role of transmitting loads such as axial force and torque. The axial force and torque are both transmitted through the flange. There is stress concentration near the transition between the flange and the cylinder.

[0025] Therefore, the area near the rear flange of the combustion chamber outer casing becomes the part with the greatest stress in the entire outer casing. In order to improve the service life of the rear flange of the outer casing, the utility model proposes a combustion chamber outer casing flange structure, which can significantly improve the service life of the rear flange, thereby improving the service life of the outer casing.

[0026] For the flange structure of the combustion chamber outer casing, see Figure 3 As shown, the rear end A of the combustion chamber outer casing 61 is connected to the front flange 701 of the turbine casing, and the flange structure includes a heat insulation layer 601 arranged on the rear end inner wall surface of the combustion chamber outer casing 61. The heat insulation layer 601 is preferably annular. The material of the heat insulation layer 601 can be a material with low thermal conductivity such as a ceramic-based composite material and a porous material.

[0027] Ceramic matrix composites are a type of composite material that uses ceramic as a matrix and various fibers. The ceramic matrix can be high-temperature structural ceramics such as silicon nitride and silicon carbide. Porous materials are materials that have a network structure consisting of interconnected or closed pores, and the boundaries or surfaces of the pores are composed of pillars or plates.

[0028] The matching gap between the heat insulation layer 601 and the matching surface 611 of the combustion chamber outer casing 61 should be as small as possible to prevent the high temperature gas from directly contacting the inner wall surface of the combustion chamber outer casing 61 .

[0029] Further, the combustion chamber outer casing 61 includes a first axial section 651 and a first radial section 652, the turbine casing front flange 701 includes a second axial section 720 and a second radial section 710, and the heat insulation layer 601 includes a third axial section 661 and a third radial section 662, the third axial section 661 is arranged on the first axial section 651, and the third radial section 662 is arranged on the first radial section 652, and is arranged to have a gap with the second radial section 710. For example, the third radial section 662 is fastened to the first radial section 652 by a connecting member such as a screw 602. It can be understood that the annularly distributed heat insulation layer 601 is connected to the rear flange 610 of the combustion chamber outer casing 61 by a plurality of circumferentially distributed screws 602.

[0030] The first radial section 652 of the combustion chamber outer casing 61 and the second radial section 710 of the turbine casing front flange 701 are located radially outside the third radial section 662 and are fastened together by connecting members such as bolts, so a bolt hole 606 is provided on the rear flange 610 of the combustion chamber outer casing.

[0031] In order to reduce the temperature gradient between the inner and outer sides of the outer casing, a heat insulation blanket 65 is designed on the outer wall of the combustion chamber outer casing to keep the outer casing warm. The front end face 604 of the heat insulation layer 601 is preferably arranged upstream of the rear end face 605 of the heat insulation blanket 65, and the two overlap in a certain area, so as to ensure that the temperature gradient of the entire outer casing is reduced.

[0032] A root thickening section 603 is designed at the rear flange 610 of the combustion chamber outer casing 61, which is located downstream of the thermal insulation blanket. The root thickening section 603 can increase the wall thickness of the combustion chamber outer casing 61 to improve the stress condition of the flange root.

[0033] The above-mentioned combustion chamber outer casing flange structure covers the thermal insulation layer concentratedly near the casing rear flange, which is easy to assemble; the thermal insulation layer is used in conjunction with the thermal insulation blanket to ensure that the life of the entire casing is extended; the inner wall surface of the casing and the internal thermal insulation layer are tightly fitted to avoid direct contact between the high-temperature gas and the inner wall of the casing, reducing convective heat exchange; the root of the casing flange is locally thickened, which can significantly improve the stress situation in this area.

[0034] In combination with the introduction to the combustion chamber outer casing flange structure, it can also be understood that a combustion chamber including the combustion chamber outer casing flange structure has a better service life of the outer casing rear flange.

[0035] The present application uses specific words to describe the embodiments of the present application. For example, "one embodiment", "an embodiment", and / or "some embodiments" refer to a certain feature, structure or characteristic related to at least one embodiment of the present application. Therefore, it should be emphasized and noted that "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or multiple times in different positions in this specification does not necessarily refer to the same embodiment. In addition, some features, structures or characteristics in one or more embodiments of the present application can be appropriately combined.

[0036] Although the utility model is disclosed as above with preferred embodiments, it is not intended to limit the utility model. Any person skilled in the art can make possible changes and modifications without departing from the spirit and scope of the utility model. Therefore, any modification, equivalent change and modification made to the above embodiments based on the technical essence of the utility model without departing from the content of the technical solution of the utility model shall fall within the protection scope defined by the claims of the utility model.

Claims

1. A combustion chamber outer casing flange structure is installed on the combustion chamber outer casing, wherein the rear end of the combustion chamber outer casing is connected to the turbine casing front flange, and is characterized in that: It comprises a heat insulation layer which is arranged on the rear end inner wall surface of the combustion chamber outer casing.

2. The combustion chamber outer casing flange structure according to claim 1, characterized in that: The combustion outer casing includes a first axial section and a first radial section, and the turbine casing front flange includes a second axial section and a second radial section. The heat insulation layer includes a third axial segment and a third radial segment. The third axial segment is arranged on the first axial segment. The third radial segment is arranged on the first radial segment and is arranged to have a gap with the second radial segment.

3. The combustion chamber outer casing flange structure according to claim 2, characterized in that: The third radial segment is fastened to the first radial segment via a connecting member.

4. The combustion chamber outer casing flange structure according to claim 2, characterized in that: The first radial segment and the second radial segment are located radially outside the third radial segment and are fastened together via a connecting member.

5. The combustion chamber outer casing flange structure according to claim 1, characterized in that: The outer wall surface of the outer casing of the combustion chamber is also provided with a heat insulation blanket.

6. The combustion chamber outer casing flange structure according to claim 5, characterized in that: The front end face of the thermal insulation layer is upstream of the rear end face of the thermal insulation blanket.

7. The combustion chamber outer casing flange structure according to claim 5, characterized in that: The combustion chamber outer casing is also provided with a root thickened section, and the root thickened section is located downstream of the thermal insulation blanket.

8. The combustion chamber outer casing flange structure according to claim 1, characterized in that: The heat insulation layer is a ceramic-based composite material or a porous material.

9. The combustion chamber outer casing flange structure according to claim 1, characterized in that: The heat insulation layer is an annular heat insulation layer.

10. A combustion chamber, characterized in that It comprises the combustion chamber outer casing flange structure as described in any one of claims 1 to 9.

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