Gas turbine air intake casing and air intake system

Abstract

This application proposes a gas turbine intake casing for compressing air from a main intake passage and supplying it to the gas turbine. The casing comprises a casing port and an airflow path. The airflow path includes a first airflow branch and a second airflow branch. The first airflow branch supplies air from the casing port to the gas turbine compressor, while the second airflow branch supplies air from the casing port to the bearing cavity of the gas turbine shaft, thereby sealing the lubricating oil and gas within the bearing cavity. The intake casing proposed in this application eliminates the influence of the boundary layer effect on the intake casing by introducing the second airflow branch, while simultaneously sealing the lubricating oil and gas within the bearing cavity, resulting in a simple and compact structure.

Description

Technical Field

[0001] The present invention relates to a gas turbine, and in particular to an air intake casing and an air intake system of a gas turbine. Background Art

[0002] Boundary layers are easily formed within the intake duct of a gas turbine. This effect can further impact the turbine's intake efficiency and even cause intake separation. Specifically, according to the formula Re = ρvL / μe (where Re is the Reynolds number, ρ and μ are the fluid density and dynamic viscosity coefficients, and v and L are the characteristic velocity and characteristic length of the flow field), as the characteristic length L decreases (i.e., compact dimensions), the Reynolds number Re also decreases. For gas turbines, a lower Reynolds number makes boundary layer formation more likely. Therefore, compact gas turbine intake systems are more prone to boundary layer effects, significantly impacting intake efficiency.

[0003] To reduce the boundary layer effect of gas turbines, existing intake systems typically undergo multiple design changes. Furthermore, to avoid distortion of the overall intake flow field, the intake casing, serving as the compressor inlet, must be designed to be smoother, resulting in increased overall size, structural weight, and floor space. Furthermore, a dedicated air intake is provided within the front bearing housing to seal the oil and gas using a pressure differential. This significantly increases the complexity of the intake structure, preventing a more compact design and placing further constraints on rotor dynamics and overall turbine rigidity.

[0004] Patent CN113279988A discloses a compressor comprising an intake casing, wherein a guide cone is provided within the intake casing. The guide cone is provided with vents, allowing air to enter the guide cone through an auxiliary airflow channel. The auxiliary airflow flows from the auxiliary airflow channel into the bearing cavity, where the pumping effect of the rotating impeller draws the fuel in the bearing into the compressor system. The fuel then flows into the combustion chamber with the airflow, where it is ultimately burned. The auxiliary airflow also removes heat from the bearing. This intake casing structure directs air from the intake port into the bearing cavity through the vents in the guide cone to cool the bearing cavity, without involving any structure related to eliminating the boundary layer effect of the intake casing.

[0005] In view of the above technical problems, the present invention is specially introduced. Summary of the Invention

[0006] The main purpose of the present invention is to provide a gas turbine air intake casing and an air intake system, which are suitable for compact air intake casings and introduce a second air flow branch to eliminate the influence of the flow channel boundary layer caused by the compact structure without affecting the air intake volume of the first air flow branch; at the same time, the air flow introduced by the second air flow branch has an induced effect on the normal pressure air introduced into the bearing cavity, thereby accelerating the air flow into the bearing cavity to seal the oil and gas.

[0007] To achieve the above objectives, according to one aspect of the present invention, a gas turbine intake casing is provided. The casing is used to compress air from a main intake passage and supply it to the gas turbine. The casing comprises a casing port and an airflow path. The airflow path comprises a first airflow branch and a second airflow branch. The first airflow branch supplies air from the casing port to the gas turbine compressor, and the second airflow branch supplies air from the casing port to the bearing cavity of the gas turbine's rotating shaft, thereby sealing lubricating oil gas in the bearing cavity and reducing lubricating oil consumption.

[0008] Furthermore, the air intake casing includes a first shell and a second shell, the first shell is arranged inside the second shell, and the first shell and the second shell form a first cavity. Air enters the compressor from the casing port through the first cavity to define a first airflow branch.

[0009] Furthermore, the first shell includes a boundary layer eliminating structure, which eliminates the boundary layer effect in the airflow path and separates the second airflow branch from the first airflow branch.

[0010] Furthermore, the first shell includes a first wall plate and a second wall plate, the first wall plate is close to the first cavity, the first wall plate and the second wall plate surround and form a second cavity, and air enters the bearing cavity through the casing opening, the first cavity, and the second cavity to define a second airflow branch.

[0011] Furthermore, the second wall panel encloses and forms a bearing cavity, and the air in the second air flow branch enters the bearing cavity from the second cavity, thereby sealing the lubricating oil gas in the bearing cavity.

[0012] Furthermore, a first through-hole unit is provided on the first wall plate, and the air in the second air flow branch enters the second cavity from the first cavity through the first through-hole unit, and the first through-hole unit and the second cavity form a boundary layer elimination structure.

[0013] Furthermore, the first through hole unit includes a plurality of rows of first through hole groups distributed axially along the first wall plate.

[0014] Furthermore, the first through hole group includes a plurality of first through holes distributed along the circumference of the first wall plate.

[0015] Furthermore, the first through hole is provided in the area where the boundary layer of the first wall plate is located.

[0016] Furthermore, the amount of air in the second air flow branch is determined by one or more factors of the number of first through holes in the first through hole unit, the circumferential distance between the through holes, the axial distance between the through holes, and the diameter of the through holes.

[0017] Furthermore, the second wall plate is provided with a second through-hole unit, and the air in the second air flow branch enters the bearing cavity from the second cavity through the second through-hole unit.

[0018] Furthermore, the first through hole unit is close to the casing opening of the air intake casing.

[0019] Furthermore, the second through hole unit is away from the casing opening of the air intake casing.

[0020] Furthermore, the second through hole unit includes second through holes, and the second through holes are distributed along the circumference of the second wall plate.

[0021] Furthermore, the sum of the cross-sectional areas of the first through-holes in the first through-hole unit is smaller than the sum of the cross-sectional areas of the second through-holes in the second through-hole unit.

[0022] Furthermore, the number of the second through holes is smaller than the number of the first through holes.

[0023] Furthermore, a bearing and a lubricating oil chamber are provided in the bearing chamber. The air in the second air flow branch enters the bearing chamber, increasing the pressure on one side of the lubricating oil chamber, preventing the lubricating oil gas from escaping from the lubricating oil chamber, and reducing the lubricating oil consumption.

[0024] Furthermore, the end face of the bearing is provided with an air sealing tooth, and the air in the second air flow branch can pass through the air sealing tooth to seal the lubricating oil gas in the lubricating oil chamber.

[0025] The application of the air intake casing of the present invention achieves at least the following beneficial effects:

[0026] 1. The second airflow branch is separated from the first airflow branch in the air intake casing. This ensures the air supply flow in the compressor without affecting the airflow of the first airflow branch, and eliminates the boundary layer effect in the compact air intake casing.

[0027] 2. The second airflow branch is introduced into the bearing cavity in the intake casing. This eliminates the boundary layer in the intake casing and seals the lubricating oil and gas in the bearing cavity through air pressure, preventing the lubricating oil and gas from leaking into the flow channel and reducing lubricating oil consumption.

[0028] 3. By optimizing the boundary layer elimination structure of the air intake casing, the boundary layer elimination effect of the air intake casing is improved. The high-speed airflow generated has an ejection effect on the normal-pressure air in the bearing cavity, accelerating the airflow into the bearing cavity to seal the oil and gas;

[0029] 4. By setting up an air flow branch in the air intake casing, the dual functions of eliminating the boundary layer and bearing sealing are achieved, simplifying the air intake casing structure, making the structure compact and reducing the floor space.

[0030] To achieve the above objectives, according to another aspect of the present invention, a gas turbine intake system is provided. The gas turbine intake system includes an intake casing, an intake volute, and a central cone. The intake volute is connected to the intake casing to form a connected air passage. The central cone is disposed within the intake volute, near one end of the intake casing opening, and is connected to the bearing cavity.

[0031] The air intake system of the present invention achieves at least the following beneficial effects:

[0032] 1. In the air intake system, the second airflow branch is separated from the first airflow branch. Without affecting the airflow of the first airflow branch, the boundary layer effect in the compact air intake system is eliminated, ensuring the air supply flow in the compressor.

[0033] 2. In the intake system, the second air flow branch is led into the bearing cavity. On the basis of eliminating the boundary layer of the intake system, the lubricating oil and gas in the bearing cavity are sealed by air pressure to prevent the lubricating oil and gas from leaking into the flow channel, while reducing lubricating oil consumption.

[0034] 3. By optimizing the boundary layer elimination structure of the intake system, the boundary layer elimination effect of the intake system is improved, and the high-speed airflow generated has an ejection effect on the normal-pressure air in the bearing cavity, accelerating the airflow into the bearing cavity to seal the oil and gas;

[0035] 4. By setting up an air flow branch in the intake system, the dual functions of eliminating the boundary layer and bearing sealing are achieved, simplifying the structure of the intake system, making the structure compact and reducing the floor space. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The accompanying drawings, which constitute part of the present invention, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0037] Figure 1 A cross-sectional view of the interior of a gas turbine intake system according to an embodiment of the present invention is shown;

[0038] Figure 2 A cross-sectional view of the interior of a gas turbine intake casing according to an embodiment of the present invention is shown;

[0039] Figure 3 A schematic diagram of a first wall panel of an air intake casing of a gas turbine according to an embodiment of the present invention is shown.

[0040] The above drawings include the following reference numerals:

[0041] 10. Intake casing; 11. First air flow branch; 12. Second air flow branch; 20. Intake volute; 30. Central cone; 110. Casing opening; 120. Bearing cavity; 121. Bearing; 122. Lubricating oil cavity; 123. Gas seal tooth; 130. First shell; 140. Second shell; 131. First wall panel; 132. Second wall panel; 134. First cavity; 133. Second cavity; 1311. First through hole unit; 1312. First through hole group; 1313. First through hole; 1321. Second through hole unit. DETAILED DESCRIPTION

[0042] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0043] The present invention is described in further detail below with reference to specific embodiments. These embodiments are not to be construed as limiting the scope of protection claimed by the present invention. The term "including" when used indicates the existence of a feature, but does not exclude the existence or addition of one or more other features; the terms "lateral", "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside" and the like indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be construed as limiting the present invention; in addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be construed as indicating or implying relative importance.

[0044] In this description, it should be noted that, unless otherwise specified or limited, the terms "installed," "connected," and "connected" should be understood broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to direct connections, indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art will understand the specific meanings of these terms in the present invention. Furthermore, in the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0045] Example

[0046] The present invention provides an air intake casing of a gas turbine, such as Figure 1As shown, the intake casing is 10 in the figure, which is used to compress air from the main intake passage and supply it to the gas turbine. The air undergoes initial compression in the intake casing 10 and is then supplied to the compressor. Specifically, the intake casing 10 includes a casing port 110 and two airflow paths, namely a first airflow branch 11 and a second airflow branch 12. The first airflow branch 11 is used to supply air from the casing port 110 to the gas turbine compressor; the second airflow branch 12 is used to supply air from the casing port 110 to the bearing cavity 120 of the gas turbine's rotating shaft, thereby sealing the lubricating oil gas in the bearing cavity 120.

[0047] like Figure 2 The internal cross-sectional view of the intake casing 10 is shown. Specifically, the intake casing 10 includes a first housing 130 and a second housing 140. The first housing 130 is disposed within the second housing 140. The first and second housings 130, 140 enclose a first cavity 134. Air in the first airflow branch 11 enters through the casing opening 110 and flows into the compressor through the first cavity 134.

[0048] Furthermore, due to the relatively compact structure of the intake casing, boundary layer effects exist, affecting intake efficiency. To address this, the present invention further provides a boundary layer elimination structure on the first housing 130. This boundary layer elimination structure separates the second airflow branch 12 from the first airflow branch 11, eliminating boundary layer effects in the airflow path and simultaneously achieving a gas-tight seal for the lubricating oil within the bearing cavity 120.

[0049] Specifically, if Figure 2 As shown, the first housing 130 includes a first wall panel 131 and a second wall panel 132. The first wall panel 131 is located near the first cavity 134. The first wall panel 131 and the second wall panel 132 enclose a second cavity 133. Air enters the bearing cavity 120 through the casing opening 110, the first cavity 134, and the second cavity 133 to define a second airflow branch 12.

[0050] After entering through the casing opening 110, air is split into two paths within the first cavity 134. The second airflow branch exits the first cavity 134 and enters the second cavity 133, eliminating the boundary layer effect within the first cavity 134. Air then enters the bearing cavity 120 from the second cavity 133, sealing the lubricating oil and gas within the bearing cavity 120. The first airflow branch also enters the compressor from the first cavity 134 for further compression. Furthermore, the airflow of the second airflow branch is less than that of the first airflow branch. In other words, the exit of the second airflow branch does not affect the airflow of the first airflow branch, ensuring the compressor's air intake while eliminating the boundary layer and sealing the bearing cavity.

[0051] like Figure 3As shown, a first through-hole unit 1311 is provided on the first wall panel 131. Air in the second airflow branch 12 enters the second cavity 133 from the first cavity 134 through the first through-hole unit 1311. The first through-hole unit 1311 and the second cavity 133 together form a boundary layer elimination structure. The first through-hole unit 1311 guides part of the airflow in the first cavity 134 out, eliminating the boundary layer effect in the first cavity 134.

[0052] Specifically, the first through hole unit 1311 includes a plurality of rows of first through hole groups 1312 distributed axially along the first wall plate 131 . The first through hole group 1312 includes a plurality of first through holes 1313 distributed circumferentially along the first wall plate 131 .

[0053] The first through holes 1313 are positioned in an area of ​​the first wall panel 131 where the boundary layer is most likely to form. Furthermore, the first through holes 1313 of the first through hole unit 1311 are regularly arranged on the first wall panel 131 and are angled relative to the first wall panel 131. The accompanying drawings are for illustrative purposes only, and it should be understood that this application does not impose specific limitations on the location and arrangement of the first through holes 1313, which may be adjusted in conjunction with the air intake structure.

[0054] Furthermore, in the present application, the amount of air in the second airflow branch 12 is determined by one or more of the following factors: the number of first through holes 1313 in the first through hole unit 1311, the circumferential distance between the through holes, the axial distance between the through holes, and the through hole diameter. The amount of air in the second airflow branch 12 is calculated based on the area of ​​the boundary layer and the minimum amount of bleed air required to seal the bearing cavity 120. It should be understood that the present application does not specifically limit the number of first through holes, the circumferential distance between the through holes, the axial distance between the through holes, and the through hole diameter; these can be set based on the area of ​​the boundary layer and the minimum amount of bleed air required to seal the bearing cavity.

[0055] like Figure 2 As shown, the second wall plate 132 encloses and forms the bearing cavity 120 , and the air in the second air flow branch 12 enters the bearing cavity 120 through the second cavity 133 , thereby sealing the lubricating oil gas in the bearing cavity 120 .

[0056] The second wall plate 132 is provided with a second through-hole unit 1321. Air in the second airflow branch 12 enters the bearing cavity 120 from the second cavity 133 through the second through-hole unit 1321. The air in the second airflow branch 12 is introduced from the second cavity 133 into the bearing cavity 120 through the second through-hole unit 1321, thereby sealing the lubricating oil gas in the bearing cavity 120.

[0057] Specifically, the first through-hole unit 1311 is located near the casing opening 110 of the air intake casing 10, while the second through-hole unit 1321 is located away from the casing opening 110. The second through-hole unit 1321 includes second through-holes distributed along the circumference of the second wall panel 132. The sum of the cross-sectional areas of the first through-holes 1313 in the first through-hole unit 1311 is smaller than the sum of the cross-sectional areas of the second through-holes in the second through-hole unit 1321. Due to the differential pressure effect, airflow in the boundary layer is more likely to escape through the first through-holes 1313 into the second cavity, and then flow into the bearing cavity through the second through-holes. Furthermore, the number of second through-holes is smaller than the number of first through-holes 1313. By providing multiple first through-holes, the boundary layer is more effectively eliminated.

[0058] like Figure 2 As shown, a bearing 121 and a lubricating oil chamber 122 are provided in the bearing chamber 120. The bearing 121 is located between the bearing seat and the shaft. Air in the second airflow branch 12 enters the bearing chamber 120, increasing the pressure on one side of the lubricating oil chamber 122 to prevent the lubricating oil gas from escaping from the lubricating oil chamber 122.

[0059] Furthermore, the end surface of bearing 121 is provided with air-sealing teeth 123, through which air in second airflow branch 12 can pass to seal the lubricating oil vapor in lubricating oil chamber 122. In other words, second airflow branch 12 is injected into bearing chamber 120 and, through air pressure, cooperates with air-sealing teeth 123 to seal the lubricating oil vapor in bearing chamber 120, preventing the lubricating oil vapor from leaking into the flow channel.

[0060] The gas turbine drive device proposed in the present application has the following advantages: 1. The second air flow branch is separated from the first air flow branch in the air intake casing, and the air supply flow in the compressor is guaranteed without affecting the air flow of the first air flow branch, and the boundary layer effect in the compact air intake casing is eliminated; 2. The second air flow branch is led into the bearing cavity in the air intake casing, and on the basis of eliminating the boundary layer of the air intake casing, the lubricating oil gas in the bearing cavity is sealed by air pressure to prevent the lubricating oil gas from leaking into the flow channel; 3. By optimizing the boundary layer elimination structure of the air intake casing, the boundary layer elimination effect of the air intake casing is better, and the high-speed airflow formed has an induced effect on the normal-pressure air in the bearing cavity, accelerating the airflow into the bearing cavity to seal the oil and gas; 4. By arranging an air flow branch in the air intake casing, the dual effects of eliminating the boundary layer and bearing sealing are achieved, the air intake casing structure is simplified, and the structure is compact, reducing the footprint.

[0061] To achieve the above object, the present invention also proposes a gas turbine intake system 1, such as Figure 1As shown, a gas turbine air intake system 1 includes an air intake casing 10, an air intake volute 20, and a central cone 30. The air intake volute 20 is connected to the air intake casing 10 to form a continuous air passage. The central cone 30 is disposed within the air intake volute 20, near one end of the air intake casing 10, and connected to the bearing cavity 120. The assembly structure of the air intake volute 20, the air intake casing 10, and the central cone 30 together form a compact air intake system that is simpler and more compact than the prior art.

[0062] The gas turbine intake system proposed in the present application has the following advantages: 1. The second air flow branch is separated from the first air flow branch in the intake system, and the boundary layer effect in the compact intake system is eliminated without affecting the air flow of the first air flow branch, thereby ensuring the air supply flow in the compressor; 2. The second air flow branch is led into the bearing cavity in the intake system, and on the basis of eliminating the boundary layer of the intake system, the lubricating oil gas in the bearing cavity is sealed by air pressure to prevent the lubricating oil gas from leaking into the flow channel, while reducing the lubricating oil consumption; 3. By optimizing the boundary layer elimination structure of the intake system, the boundary layer elimination effect of the intake system is better, and the high-speed airflow formed has an induced effect on the normal-pressure air in the bearing cavity, accelerating the airflow into the bearing cavity to seal the oil and gas; 4. By setting an air flow branch in the intake system, the dual effects of eliminating the boundary layer and bearing sealing are achieved, the structure of the intake system is simplified, and the structure is compact, reducing the footprint.

[0063] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A gas turbine intake casing, used for compressing air from a main intake passage and supplying it to the gas turbine, characterized in that: The gas turbine comprises a casing port and an airflow passage, wherein the airflow passage comprises a first airflow branch and a second airflow branch, wherein the first airflow branch supplies the air from the casing port to the compressor of the gas turbine, and the second airflow branch supplies the air from the casing port to the bearing cavity of the rotating shaft of the gas turbine to seal the lubricating oil gas in the bearing cavity; The air intake casing includes a first shell and a second shell, the first shell is arranged inside the second shell, and the first shell and the second shell enclose a first cavity. The air enters the compressor from the casing opening through the first cavity to define the first airflow branch. The first housing includes a first wall plate and a second wall plate, the first wall plate being close to the first cavity, the first wall plate and the second wall plate enclosing and forming a second cavity, the air entering the bearing cavity through the casing opening, the first cavity, and the second cavity to define the second airflow branch; The first wall plate is provided with a first through-hole unit, and the air in the second air flow branch passes through the first through-hole unit and enters the second cavity from the first cavity, and the first through-hole unit and the second cavity form a boundary layer elimination structure; The second wall plate is provided with a second through-hole unit, and the air in the second air flow branch passes through the second through-hole unit and enters the bearing cavity from the second cavity; The first through hole unit is close to the casing opening of the air intake casing; The second through hole unit is away from the casing opening of the air intake casing; The second through hole unit includes second through holes, and the second through holes are distributed along the circumference of the second wall plate; The sum of the cross-sectional areas of the first through-holes in the first through-hole unit is smaller than the sum of the cross-sectional areas of the second through-holes in the second through-hole unit; The number of the second through holes is smaller than the number of the first through holes.

2. The air intake casing according to claim 1, characterized in that: The first shell includes a boundary layer elimination structure, which eliminates the boundary layer effect in the airflow path and separates the second airflow branch from the first airflow branch.

3. The air intake casing according to claim 2, characterized in that: The second wall panel encloses and forms the bearing cavity. The air in the second air flow branch enters the bearing cavity through the second cavity, thereby sealing the lubricating oil gas in the bearing cavity.

4. The air intake casing according to claim 1, wherein: The first through-hole unit includes a plurality of rows of first through-hole groups distributed axially along the first wall plate.

5. The air intake casing according to claim 4, characterized in that: The first through-hole group includes a plurality of first through-holes distributed along the circumference of the first wall plate.

6. The air intake casing according to claim 5, characterized in that: The first through hole is arranged in the area where the boundary layer of the first wall plate is located.

7. The air intake casing according to claim 5 or 6, characterized in that: The amount of air in the second air flow branch is determined by one or more factors of the number of first through holes in the first through hole unit, the circumferential distance between the through holes, the axial distance between the through holes, and the diameter of the through holes.

8. The air intake casing according to claim 1, characterized in that: The bearing cavity is provided with a bearing and a lubricating oil cavity. The air in the second air flow branch enters the bearing cavity, increasing the pressure on one side of the lubricating oil cavity, preventing lubricating oil gas from escaping from the lubricating oil cavity, and reducing lubricating oil consumption.

9. The air intake casing according to claim 8, characterized in that: The end surface of the bearing is provided with air sealing teeth, and the air in the second air flow branch can pass through the air sealing teeth to seal the lubricating oil gas in the lubricating oil chamber.

10. A gas turbine air intake system, characterized in that: The gas turbine intake system comprises an intake casing, an intake volute and a central cone according to any one of claims 1 to 9, The air intake volute is connected to the air intake casing to form a connected air passage, and the central cone is arranged inside the air intake volute. The central cone is close to one end of the casing opening of the air intake casing, and the central cone is connected to the bearing cavity.

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