High-temperature load-bearing casing comprehensive cooling structure and method

Abstract

The application provides a high-temperature load-bearing casing comprehensive cooling structure and a cooling method. The high-temperature load-bearing casing comprehensive cooling structure is located between a high-pressure turbine and a low-pressure turbine and comprises a casing main body, a sandwich cavity arranged in the casing main body, and an air duct arranged on the casing main body in a circumferential direction and used for introducing cooling air flow from two gas streams of a combustion chamber into the sandwich cavity. The cooling air flow in the sandwich cavity flows in a direction opposite to a main flow direction, sequentially cools a rear section of the casing, a middle section of the casing and a low-pressure turbine guide vane, and then enters a front cavity of a low-pressure rotor to realize rim sealing. The load-bearing casing combines a flow channel thin-wall part, a thin-wall hollow support plate, a metal seal, a hollow guide vane and other structures, ensures a cooling air flow channel, and has the advantages of simple structure, light weight and complete functions.

Description

Technical Field

[0001] This invention relates to the field of aero-engine technology, specifically to a high-temperature load-bearing casing integrated cooling structure and method. Background Technology

[0002] In the field of aero-engine technology, the high-temperature load-bearing casing, as the core load-bearing and protective component of the turbine system, directly bears the scouring effect of the high-temperature exhaust gas from the combustion chamber and the complex loads transmitted by the rotor. Its operational reliability and service life directly determine the overall performance and flight safety of the aero-engine. To avoid failures such as material mechanical property degradation and cracking caused by excessive thermal stress due to high temperatures, existing technologies generally adopt a secondary air cooling scheme. This involves introducing the cooling airflow from the compressor into the high-temperature load-bearing casing area to achieve cooling and protection of the casing. This is also the mainstream technical approach for cooling aero-engine turbine casings.

[0003] The prior art closest to this application mainly falls into two categories: one category adopts a single cooling air path design, which introduces the cooling airflow from one end of the casing, flows unidirectionally along the surface or inner cavity of the casing, and then discharges it directly without making multi-area coordinated use of the cooling airflow; the other category adopts a segmented cooling method, which designs independent cooling channels for different sections of the casing, but each channel is independent of each other and does not cooperate. After completing the cooling of a single section, the cooling airflow directly merges into the mainstream and is not further used for cooling other high-temperature components of the engine.

[0004] While the aforementioned existing technologies can reduce the temperature of the high-temperature load-bearing casing to some extent, they still have many shortcomings and cannot meet the design requirements of high reliability and long service life for aero engines. Specific problems include: First, low cooling airflow utilization and significant energy waste; second, poor casing temperature control and prominent thermal stress risks; third, lack of effective high-temperature gas sealing synergy; and fourth, complex cooling structure design and poor adaptability.

[0005] In summary, existing cooling technologies for high-temperature load-bearing casings of aero engines have significant shortcomings in terms of cooling airflow utilization, casing temperature control, high-temperature gas sealing, and structural adaptability, and cannot fully meet the long-term stable operation requirements of high-temperature load-bearing casings. Summary of the Invention

[0006] In view of this, the present invention provides a comprehensive cooling structure and method for a high-temperature load-bearing casing, so as to maximize the utilization of cooling airflow and accurately control the casing temperature and temperature gradient.

[0007] This invention provides the following technical solution: a high-temperature load-bearing casing integrated cooling structure, located between high-pressure and low-pressure turbines, comprising: a casing body, wherein a jacketed cavity is provided within the casing body, the jacketed cavity being formed by thin-walled components welded to the casing body; and an air intake pipe, circumferentially distributed on the casing body, for introducing cooling airflow from two streams of airflow from the combustion chamber into the jacketed cavity; the cooling airflow within the jacketed cavity flows in a direction opposite to the mainstream direction, sequentially cooling the rear section of the casing, the middle section of the casing, and the low-pressure turbine guide vanes, before entering the front cavity of the low-pressure rotor to achieve rim sealing.

[0008] A comprehensive cooling method for a high-temperature load-bearing casing includes the following steps:

[0009] The two streams of airflow from the combustion chamber are introduced into the interlayer cavity of the high-temperature load-bearing casing body through circumferentially distributed air intake pipes. The cooling airflow flows in the sandwich cavity in the opposite direction to the mainstream direction, cooling the rear section of the casing, the middle section of the casing, and the low-pressure turbine guide vanes in sequence. The cooling airflow flowing out of the low-pressure turbine guide vanes enters the front cavity of the low-pressure rotor, sealing the wheel rim and preventing the mainstream high-temperature gas from entering the disk cavity.

[0010] Compared with the prior art, the beneficial effects that the at least one technical solution adopted by the present invention can achieve include at least the following: The designed high-temperature load-bearing casing integrated cooling air path and structure can achieve efficient utilization of cooling airflow. The airflow sequentially cools the rear section, middle section, and guide vane rear sealing rotor rim of the load-bearing casing. This air path scheme can realize multiple utilization of a single airflow and a more uniform cooling temperature difference, so as to achieve effective control of the casing temperature gradient. This load-bearing casing integrates thin-walled flow channel components, thin-walled hollow support plates, metal seals, hollow guide vanes, and other structures, ensuring a cooling airflow channel while being simple in structure, lightweight, and fully functional. Attached Figure Description

[0011] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0012] Figure 1 This is a schematic diagram of the cross-sectional structure of the load-bearing casing. Figure 2 This is a three-dimensional structural diagram of the load-bearing casing; Figure 3 yes Figure 2 A magnified view of a portion of the image.

[0013] The attached figures are labeled as follows: 1. High-temperature main stream; 2. Thin-walled hollow support plate; 3. Low-pressure turbine guide vane; 4. Low-pressure rotor; 5. Cooling airflow; 6. Two airflows in the combustion chamber; 7. Air intake pipe; 8. Casing body; 9. First metal seal; 10. Second metal seal; 11. Thin-walled component; 12. Rib. Detailed Implementation

[0014] The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0015] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0016] Example 1 See Figure 1 This embodiment provides a high-temperature load-bearing casing integrated cooling structure located between the high- and low-pressure turbines. The structure includes a casing body 8, which is axially divided into a front section, a middle section, and a rear section. The casing body 8 contains a sandwich cavity, which is enclosed by thin-walled members 11 welded to the casing body 8. The thin-walled members 11 are multiple circumferentially arranged, dividing the sandwich cavity circumferentially into multiple independent small chambers to ensure that the cooling airflow 5 is evenly distributed within each independent small chamber, avoiding uneven circumferential temperature distribution.

[0017] The air intake pipes 7 are evenly distributed around the casing body 8 and are used to introduce the cooling airflow 5 from the two airflows 6 in the combustion chamber into the interlayer cavity. The number of air intake pipes 7 corresponds to the number of independent small cavities formed by the circumferential division of the interlayer cavity. Each air intake pipe 7 supplies air to one independent small cavity, so as to achieve uniform air intake.

[0018] After the cooling airflow 5 enters the jacket cavity, it flows in the opposite direction to the high-temperature mainstream 1, that is, in the counter-current direction from back to front, it flows through the rear section of the casing (near the flange section), the middle section of the casing (outer ring section of the turbine rotor) in sequence, and then flows through the outer ring and inner wall of the low-pressure turbine guide vane 3, thereby cooling each of the above sections in sequence.

[0019] The inner and outer flow channels in the middle section of the casing are connected as one unit by the low-pressure turbine guide vane 3. The low-pressure turbine guide vane 3 is a hollow structure. The hollow inner cavity of the low-pressure turbine guide vane 3 allows the cooling airflow 5 to flow through, and at the same time, the low-pressure turbine guide vane 3 transfers the rotor load outward to realize the structural load-bearing function. The cooling airflow 5 flowing out of the hollow inner cavity of the low-pressure turbine guide vane 3 enters the front cavity of the low-pressure rotor 4 to seal the rim and prevent the high-temperature mainstream 1 high-temperature combustion gas from entering the disk cavity.

[0020] See Figure 1The front section of the casing is welded to the middle section of the casing via thin-walled components. The inner and outer flow channels of the front section of the casing are connected as one unit by thin-walled hollow support plates 2. The outer side of the thin-walled hollow support plate 2 forms a mainstream channel for adjusting the airflow direction, allowing the high-temperature mainstream 1 to flow. The support plate cavity of the thin-walled hollow support plate 2 allows the cooling airflow 5 to flow, and the support plate cavity is also used to install the supply and return oil pipelines, realizing the integrated arrangement of the supply and return oil pipelines in the bearing cavity.

[0021] The end of the front thin-walled component near the air intake side is not reinforced to allow the casing to undergo free thermal expansion under high-temperature operating conditions, thereby reducing thermal stress. A first metal seal 9 and a second metal seal 10 are provided between the end of the front thin-walled component near the air intake side and adjacent parts to prevent high-temperature combustion gas from flowing back into the interlayer cavity and the inner cavity of the casing.

[0022] Example 2 See Figure 2 and Figure 3 This embodiment further optimizes the cooling structure based on embodiment 1, adds ribs 12 to the inner wall of the sandwich cavity to enhance heat exchange, and strengthens the air intake end of the front thin-walled component.

[0023] In this embodiment, the basic arrangement of the casing body 8, thin-walled component 11, air duct 7, low-pressure turbine guide vane 3, thin-walled hollow support plate 2, first metal seal 9 and second metal seal 10 is the same as in embodiment 1. The interlayer cavity is also formed by being enclosed by thin-walled component 11 and is divided into multiple independent small cavities by multiple thin-walled components 11 in the circumferential direction. The number of air ducts 7 corresponds to the number of independent small cavities, and each air duct 7 supplies air to one independent small cavity.

[0024] In this embodiment, ribs 12 are arranged on the inner wall surface of the sandwich cavity (i.e. the wall surface near the high-temperature mainstream 1) along the flow direction of the cooling airflow 5. The rib spacing and rib height of the ribs 12 are set according to the heat exchange requirements of each section of the casing rear section, casing middle section and low-pressure turbine guide vane 3, so as to enhance the convective heat exchange between the inner wall surface of the sandwich cavity and the cooling airflow 5 and improve the cooling effect of each section.

[0025] In this embodiment, the end of the front thin-walled component near the air intake side is welded to an annular machined part. The annular machined part reinforces the end of the front thin-walled component, improving its structural rigidity under high-temperature conditions. Simultaneously, the annular machined part serves as the sealing end face of the first metal seal 9 and the second metal seal 10, cooperating with adjacent parts to prevent backflow of high-temperature combustion gases. The end of the front thin-walled component near the air intake side is not reinforced to ensure free thermal expansion under high-temperature conditions.

[0026] After entering the jacket cavity, the cooling airflow 5 flows in the opposite direction to the high-temperature mainstream 1. During the flow, it passes through the ribs 12 arranged on the inner wall of the jacket cavity, which enhance convective heat transfer, thereby cooling the rear section of the casing, the middle section of the casing, and the low-pressure turbine guide vane 3 in sequence. The cooling airflow 5 flows through the hollow inner cavity of the low-pressure turbine guide vane 3, providing convective cooling to the low-pressure turbine guide vane 3; at the same time, the cooling airflow 5 flows through the support plate cavity of the thin-walled hollow support plate 2, providing convective cooling to the thin-walled hollow support plate 2. Finally, the cooling airflow 5 enters the front cavity of the low-pressure rotor 4, sealing the rim and preventing the high-temperature mainstream 1 from entering the disk cavity.

[0027] Example 3 See Figure 1 This embodiment provides a comprehensive cooling method for a high-temperature load-bearing casing based on the cooling structure described in Embodiment 1, specifically including the following steps: The two airflows 6 from the combustion chamber are introduced into the independent small cavities of the jacket cavity of the casing body 8 through circumferentially distributed air intake pipes 7. The number of air intake pipes 7 corresponds to the number of independent small cavities, with each air intake pipe 7 supplying air to one independent small cavity, ensuring that the cooling airflow 5 is circumferentially and evenly distributed within the jacket cavity.

[0028] The cooling airflow 5 flows in the jacket cavity in the opposite direction to the high-temperature mainstream 1, and flows sequentially through the rear section of the casing (near the flange section), the middle section of the casing (outer ring section of the turbine rotor), and the outer ring and inner wall of the low-pressure turbine guide vane 3, thereby cooling the rear section of the casing, the middle section of the casing, and the low-pressure turbine guide vane 3 in sequence.

[0029] The cooling airflow 5 that flows out of the hollow inner cavity of the low-pressure turbine guide vane 3 enters the front cavity of the low-pressure rotor 4, and seals the wheel rim to prevent the high-temperature mainstream gas 1 from entering the disk cavity, thus protecting the disk cavity structure of the low-pressure rotor 4.

[0030] Example 4 See Figure 2 and Figure 3 This embodiment provides a comprehensive cooling method for a high-temperature load-bearing casing based on the cooling structure described in Embodiment 2. Building upon Embodiment 3, it further enhances the heat exchange and cooling effect of each component, specifically including the following steps: The two streams of airflow 6 from the combustion chamber are introduced into the interlayer cavity of the casing body 8 through the circumferentially distributed air intake pipes 7, and the cooling airflow 5 is evenly distributed to each independent small cavity.

[0031] The cooling airflow 5 flows in the jacket cavity in the opposite direction to the high-temperature mainstream 1. During the flow, it passes through the ribs 12 arranged on the inner wall of the jacket cavity. The rib spacing and rib height of the ribs 12 are set according to the heat exchange requirements. The ribs 12 enhance convective heat transfer, thereby providing enhanced cooling to the rear section of the casing, the middle section of the casing, and the low-pressure turbine guide vane 3 in sequence. The cooling airflow 5 flows through the hollow inner cavity of the low-pressure turbine guide vane 3 to achieve convective cooling of the low-pressure turbine guide vane 3; at the same time, the cooling airflow 5 flows through the support plate cavity of the thin-walled hollow support plate 2 to achieve convective cooling of the thin-walled hollow support plate 2.

[0032] The cooling airflow 5 that flows out of the hollow inner cavity of the low-pressure turbine guide vane 3 and the support plate cavity of the thin-walled hollow support plate 2 enters the front cavity of the low-pressure rotor 4, and seals the wheel rim to prevent the high-temperature mainstream 1 from entering the disk cavity.

[0033] The above description is merely a specific embodiment of the present invention and should not be construed as limiting the scope of the invention. Therefore, substitutions of equivalent components, or equivalent changes and modifications made within the scope of protection of the present invention, should still fall within the scope of the present invention. Furthermore, the technical features, technical features and technical solutions, and technical solutions in the present invention can be freely combined and used.

Claims

1. A high-temperature load-bearing casing integrated cooling structure, located between high and low pressure turbines, characterized in that, include: The casing body has a sandwich cavity inside, which is formed by thin-walled members welded to the casing body; The air intake pipes are circumferentially distributed on the main body of the casing and are used to introduce cooling airflow from the two airflows in the combustion chamber into the interlayer cavity. The cooling airflow in the sandwich cavity flows in the opposite direction to the mainstream direction, and cools the rear section of the casing, the middle section of the casing and the low-pressure turbine guide vanes in sequence before entering the front cavity of the low-pressure rotor to achieve rim sealing.

2. The high-temperature load-bearing casing integrated cooling structure according to claim 1, characterized in that, The thin-walled component is a circumferentially multi-component component, which divides the interlayer cavity into multiple independent small cavities along the circumference to ensure uniform distribution of cooling airflow.

3. The high-temperature load-bearing casing integrated cooling structure according to claim 2, characterized in that, The inner wall of the sandwich cavity is provided with ribs along the direction of cooling airflow, and the rib spacing and rib height are set according to the heat exchange requirements.

4. The high-temperature load-bearing casing integrated cooling structure according to claim 1, characterized in that, The inner and outer flow channels in the middle section of the casing are connected as one unit by low-pressure turbine guide vanes. The low-pressure turbine guide vanes are hollow structures that allow cooling airflow and transfer rotor load outward.

5. The high-temperature load-bearing casing integrated cooling structure according to claim 4, characterized in that, The main body of the casing also includes a front section, which is welded to the middle section of the casing by a thin-walled component; the inner and outer flow channels of the front section are connected as one piece by a thin-walled hollow support plate, which is a hollow structure with a main flow channel on its outer side that can adjust the airflow direction, and its support plate cavity is used for cooling airflow and for installing oil supply and return pipelines.

6. The high-temperature load-bearing casing integrated cooling structure according to claim 5, characterized in that, The end of the front thin-walled component near the air intake side is not reinforced to allow free thermal expansion at high temperatures; a metal seal is provided between the end and the adjacent component to prevent backflow of fuel gas.

7. The high-temperature load-bearing casing integrated cooling structure according to claim 6, characterized in that, The end of the front thin-walled component near the air intake side is welded to an annular machined component, which reinforces the thin-walled component and serves as the sealing end face of the metal seal.

8. The high-temperature load-bearing casing integrated cooling structure according to claim 1, characterized in that, The number of air intake tubes corresponds to the number of independent small cavities formed by the circumferential division of the interlayer cavity, with each air intake tube supplying air to one independent small cavity.

9. A comprehensive cooling method for a high-temperature load-bearing casing, characterized in that, Includes the following steps: The two streams of airflow from the combustion chamber are introduced into the interlayer cavity of the high-temperature load-bearing casing body through circumferentially distributed air intake pipes. The cooling airflow flows in the sandwich cavity in the opposite direction to the mainstream direction, cooling the rear section of the casing, the middle section of the casing, and the low-pressure turbine guide vanes in sequence. The cooling airflow flowing out of the low-pressure turbine guide vanes enters the front cavity of the low-pressure rotor, sealing the wheel rim and preventing the mainstream high-temperature gas from entering the disk cavity.

10. The comprehensive cooling method for high-temperature load-bearing casing according to claim 9, characterized in that, The cooling airflow flows through the ribs arranged on the inner wall of the sandwich cavity to enhance convective heat transfer; the cooling airflow flows through the hollow inner cavity of the low-pressure turbine guide vane and through the support plate cavity of the thin-walled hollow support plate to achieve convective cooling of the low-pressure turbine guide vane and the thin-walled hollow support plate.

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