Staggered cascade structure, gas compressor and aero-engine

Abstract

The staggered blade grid structure comprises a plurality of adjustable stator blades distributed in the circumferential direction, each adjustable stator blade comprises a rotating shaft, a rocker arm assembly and a blade body, and the axial positions of the rotating shafts are distributed in a staggered mode. The invention further provides a gas compressor and an aero-engine adopting the staggered cascade structure. According to the staggered blade grid structure, the rotating shafts of the adjustable stator blades are arranged in the axial staggered mode, the existing space is effectively utilized, the problem of interference of the blade structure is solved, and the design requirement for high consistency of the adjustable stator can be met.

Description

Technical Field

[0001] This invention relates to the field of aero-engines, and more specifically to the field of adjustable stator structures. Background Technology

[0002] Variable stator vanes (VSVs) are stator vanes that can rotate within a certain range along a radial axis. When the compressor operates at different speeds and the flow rates of the upstream and downstream stages are mismatched, the rotation angle of the variable stator vanes can be adjusted to achieve flow rate matching at different speeds, thus avoiding situations such as "upstream surge followed by downstream blockage" or "upstream blockage followed by upstream surge".

[0003] A blade cascade is formed by arranging multiple blades at certain intervals, and the geometric parameters of the cascade are directly related to the aerodynamic performance of the compressor. Blade cascade density indicates the density of the blade arrangement. The load in the front stage of an axial compressor is relatively high, requiring increased density to reduce the load on individual blades. However, further increasing the density can easily cause structural interference in the rotating frustum of the adjustable stator blades. Summary of the Invention

[0004] One objective of this invention is to provide an interleaved blade cascade structure that effectively avoids the problem of interference between the rotating frustum structure of the blades in high-density designs, while also meeting rotation requirements.

[0005] To achieve the above objective, the staggered blade cascade structure includes a plurality of circumferentially distributed adjustable stator blades, each of which includes a rotating shaft, a rocker arm assembly, and a blade body, with the axial positions of the rotating shafts being staggered.

[0006] In one or more embodiments, the axial positions of the blade bodies are staggered.

[0007] In one or more embodiments, each of the adjustable stator blade bodies has the same axial position.

[0008] In one or more embodiments, the adjustable stator blade further includes a frustum disposed at the end of the blade body, the axial positions of the frustums being staggered.

[0009] In one or more embodiments, the blade body includes a root portion and a tip portion, the tip portion being connected to the rocker arm assembly, the root portion forming a gap with the rotor disk, and the gap value of the root portion from the leading edge to the trailing edge being the same value, to form a cantilevered adjustable stator blade.

[0010] In one or more embodiments, the gap value is 0.2 to 0.6 mm.

[0011] In one or more embodiments, the axial deviation of the rotating shaft is 1 mm to 50 mm.

[0012] In one or more embodiments, the cascade density of the staggered cascade structure is greater than 1.5.

[0013] Another object of the present invention is to provide a compressor whose inlet adjustable stator adopts the above-described staggered cascade structure.

[0014] Another object of the present invention is to provide an aircraft engine including the above-described compressor.

[0015] The aforementioned staggered blade cascade structure effectively utilizes existing space and avoids interference issues in the blade structure by setting the rotation axes of the adjustable stator blades in an axially staggered arrangement, thus meeting the design requirements for high density of the adjustable stator. Furthermore, the adjustable stator blades are installed in a cantilever structure, eliminating the original boss structure and further avoiding interference between the rotating frustums at the root of the crowned stator. This simplifies the structural form at the root of the blade body, reduces structural weight, and simultaneously prevents the mixing of the grate leakage flow with the mainstream, reducing the accumulation of low-energy fluid at the root, lowering aerodynamic losses, and improving the stability margin of the compressor. Attached Figure Description

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

[0017] Figure 1 This is a schematic diagram of a traditional crowned imported adjustable stator structure;

[0018] Figure 2 This is a schematic diagram of a cantilevered adjustable stator structure.

[0019] Figure 3 It is a cross-sectional view of the blade body with staggered axial positions;

[0020] Figure 4 It is an oblique cross-sectional view of the blade body with the same axial position;

[0021] Figure 5 This is a top view of one embodiment of an axially staggered cascade structure;

[0022] Figure 6 This is a top view of another embodiment of the axially staggered blade cascade structure.

[0023] Explanation of reference numerals in the attached figures

[0024] 10 Adjustable stator

[0025] 11 Rotation axis

[0026] 12 Rocker arm assembly

[0027] 13. Blade body

[0028] 14. Rotating truncated cone of the casing

[0029] 15. Wheel hub rotating platform

[0030] 16. Honeycomb structure

[0031] 20 moving leaves

[0032] 21 Rotor disc

[0033] 30 Casing

[0034] 100 Engine rotation axis

[0035] 131 Leaf tip

[0036] 132 Leaf root part

[0037] 210 Toothpick

[0038] Gap A, C

[0039] B. Boss structure

[0040] E circumferential line Detailed Implementation

[0041] The present invention will be further described below with reference to specific embodiments and accompanying drawings. More details are set forth in the following description in order to provide a full understanding of the present invention. However, the present invention can obviously be implemented in many other ways different from those described herein. Those skilled in the art can make similar extensions and derivations based on actual application situations without departing from the spirit of the present invention. Therefore, the scope of protection of the present invention should not be limited by the content of this specific embodiment.

[0042] It should be noted that these and other accompanying figures are merely examples and are not drawn to scale. They should not be used as a limitation on the actual scope of protection of this invention. The X-axis represents the circumferential direction, the Y-axis represents the axial direction, and the Z-axis represents the radial direction.

[0043] An aero engine comprises major structures such as a fan, compressor, turbine, and combustion chamber. The fan draws in a large volume of air, while the compressor compresses the air drawn into the core, progressively increasing its pressure and temperature to achieve efficient combustion in the combustion chamber. The combustion chamber mixes the high-pressure air and fuel, igniting the fuel to produce high-temperature, high-pressure combustion gases. The turbine uses these gases to drive the fan and compressor, expelling the expanded airflow at high speed, generating thrust.

[0044] An air compressor is a component used to compress gas to increase its pressure and kinetic energy, mainly consisting of a rotor and a stator. The rotor consists of multiple stages of moving blades that compress the gas stage by stage as it rotates. The stator is a fixed annular structure that includes stationary blades located between the rotors, used to guide the airflow and increase the compression effect. In an axial-flow compressor, the airflow is parallel to the axis, flowing axially through the staged rotor-stator structure, with the pressure increasing stage by stage. The angle, velocity, and spacing of each stage of the blades directly determine the compressor's performance.

[0045] Variable stator vanes (VSVs) are a common adjustment mechanism used in compressors. They allow for adjustment of the stator vane angle to meet flow matching requirements at different compressor speeds. Multiple rows of adjustable stator vanes are circumferentially distributed to form a stator vane cascade structure, which guides and regulates the airflow direction.

[0046] Figure 1 The diagram illustrates a conventional crowned inlet adjustable stator structure. The blade cascade structure formed by the adjustable stator rotates around the engine's rotation axis 100. Moving blades 20 and 20' are mounted on the rotor disk 21. The adjustable stator 10 is positioned between two adjacent moving blades 20 and 20' and includes a rotating shaft 11, a rocker arm assembly 12, and a blade body 13. The rotating shaft 11 is rotatably mounted on the casing 30, and its rotation angle is adjusted via the rocker arm assembly 12.

[0047] For example, the rocker arm assembly 12 includes a rocker arm, an adjusting ring, a push rod or connecting rod mechanism, and a drive mechanism. The rocker arm is a lever structure fixedly connected to the stator blade and installed at the end of each stator blade. The rocker arm is connected to the adjusting mechanism through a connecting mechanism (such as a push rod or connecting rod), and its rotation drives the blade to rotate together. The adjusting ring is connected to all rocker arms and has a ring structure. The push rod or connecting rod connects the adjusting ring and the rocker arm. During operation, according to the compressor's operating status or working conditions, the control system sends a signal to the drive mechanism, which drives the adjusting ring to rotate through the push rod or connecting rod, causing all rocker arms to rotate synchronously, thereby changing the blade angle.

[0048] The blade body 13 includes a blade tip portion 131 and a blade root portion 132. At the top and bottom of the blade tip portion 131, a casing rotating platform 14 and a hub rotating platform 15 are respectively provided.

[0049] The trailing edge of the blade tip portion 131, that is, the tail end along the -Y direction, has a partial gap A with the casing flow channel; the leading edge of the blade tip portion 131 is fused with the rotation shaft 11. This blade configuration has the same radial clearance value as the outer casing from a certain chord length position of the blade to the trailing edge, such as 0.5 mm.

[0050] Furthermore, the leading edge of the blade root portion 132 is fused with the rotating shaft 11, forming a radial gap of 0.5 mm from a certain chord length position to the trailing edge and the inner flow channel. The blade root portion 132 has a honeycomb structure 16 arranged at the sealing ring position, which is spaced apart from the grates 210 of the rotor disk 21, with a gap value of 0.5 mm between it and the grates 210.

[0051] The honeycomb structure in this part of the blade root region forms a boss structure B. Boss structure B will interfere with the mainstream flow field, causing flow losses and introducing certain uncertainties into the aerodynamic design of the compressor; this boss structure will also cause interference between the roots of adjacent blades in conventionally designed adjustable stators.

[0052] Blade density refers to the ratio of the blade chord length to the pitch of adjacent blades, generally indicating the density of the blade arrangement. A higher blade density results in a denser blade arrangement. Arranging a sufficient number of blades within a limited space while ensuring adequate rotation space for each blade remains a design challenge. Furthermore, the boss structures in the aforementioned configuration exacerbate interference between adjacent blade bosses and the actuation mechanism. Structural interference and aerodynamic flow losses further complicate compressor design.

[0053] To address the above problems, this invention proposes a staggered blade cascade structure. Based on conventional adjustable stator blades, the axial positions of the rotation axes 11 of each adjustable stator are arranged in a staggered distribution, such as... Figure 3 and Figure 4 As shown, the rotation axes 11 and 11' of adjacent adjustable stators 10 and 10' are staggered in the axial direction.

[0054] Specifically, one of the rotation axes of adjacent blades is conventionally set, while the other is moved forward a certain distance along the axial direction to form an interleaved distribution structure, which allows each blade to have a certain rotation space. Under the premise of a large blade cascade density, this structure can fully meet the rotation requirements of each stationary blade and ensure that there is no interference between the frustums of adjacent blades.

[0055] Furthermore, the root of the adjustable stator is designed as a cantilever structure, such as... Figure 2 As shown, the blade root portion 132 and the rotor disk 21 form a gap C. Preferably, the gap value of the blade root portion 132 from the leading edge to the trailing edge is the same, so as to form a cantilevered adjustable stator blade.

[0056] Therefore, this cantilever structure design eliminates the root boss structure, avoiding interference problems caused by the root boss. Combined with the staggered design of the rotating shaft, it can prevent interference between adjacent blades and meet the rotation requirements.

[0057] The value of the gap C can range from 0.2 to 0.6 mm, preferably 0.5 mm. Those skilled in the art will understand that the range of the gap value can be adjusted according to the actual application.

[0058] Based on this, the axial position of the blade body 13 can be set to a staggered distribution, or it can be set to have the same axial position, as shown below. Figure 5 and Figure 6 As shown.

[0059] Figure 5 and Figure 3 The blade bodies 13 are shown in an alternating arrangement. The leading edges of the blade bodies 13, that is, the ends along the Y direction, are located at different axial positions. In an adjacent blade body 13, 13', the rotation axis and the end of the blade body of one blade are arranged normally, while the rotation axis and the end of the blade body of the other blade are moved a certain distance along the axial direction, forming a structure in which the blade bodies and rotation axes are alternating.

[0060] Figure 6 and Figure 4 The blade bodies 13 are shown in the same axial position. The leading edges of the blade bodies 13 are all located on the same circumferential line E, but the positions of adjacent blades and their respective rotation axes are different: the blades and adjacent blades are located in the same axial position, and the rotation axes of the blades and the rotation axes of the adjacent blades are staggered in the axial direction.

[0061] When the blade density is high, it is difficult to arrange the rotating bosses. Therefore, the rotating shafts are set to be staggered to solve the problem.

[0062] After the blade bodies are staggered, considering the adverse effects of the axial spacing between the upstream and downstream sides and the unevenness in the circumferential direction, the blade design needs to be improved accordingly. However, if the rotation axes are staggered while the blade bodies are aligned axially, the blades can still maintain their original aerodynamic design characteristics without adjustment.

[0063] In some embodiments, the frustums disposed at the ends of the blade body are staggered in axial position. For example... Figure 5 and Figure 6 As shown, the axial positions of the rotating frustum 14 of the casing are staggered, which can wrap the blade more fully, thereby reducing the range of the gap A, reducing the area of ​​the tip gap leakage flow, reducing the mixing of the leakage flow with the mainstream, and thus reducing aerodynamic losses. In addition, the adjustable stator blade tip is more fully wrapped with the rotating frustum, effectively improving the blade stiffness and avoiding blade structural damage caused by forced response.

[0064] In some embodiments, such as Figure 4 As shown, the axial deviation value L of the rotating shaft 11 is 1mm to 50mm, preferably 5mm to 20mm.

[0065] Based on conventional adjustable stator blades, the above-mentioned staggered blade structure designs the root of the adjustable stator as a cantilever structure, with the root clearance value being the same from the leading edge to the trailing edge. The position of the front mounting shaft of the outer casing is determined according to the position of the front mounting shaft, the size of the rotating frustum, and the blade consistency to ensure that adjacent blades do not interfere with each other, resulting in the final axially staggered cantilever structure adjustable stator blade.

[0066] The above structure simplifies the structural form of the adjustable stator root, eliminates the mixing of leakage flow and mainstream flow in the adjustable stator root cavity, avoids flow losses caused by root bosses, improves the flow field at the root of the adjustable stator blade, increases surge margin, meets the design requirement of non-interference between rotating bosses under high consistency conditions greater than 1.5, meets rotation requirements, reduces aerodynamic losses, and improves blade performance.

[0067] Based on the above description of the staggered blade cascade structure, it can also be understood that a compressor including an adjustable inlet stator employing the above staggered blade cascade structure has better aerodynamic performance.

[0068] It can also be understood as an aircraft engine with the aforementioned compressor.

[0069] In the description of this application, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is usually based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this application and simplifying the description. Unless otherwise stated, these directional terms do not 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 on the scope of protection of this application; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0070] Furthermore, this application uses specific terms to describe embodiments of the application. For example, "an embodiment," "one embodiment," and / or "some embodiments" refer to a particular feature, structure, or characteristic related to at least one embodiment of the application. Therefore, it should be emphasized and noted that "an embodiment," "one embodiment," or "an alternative embodiment" mentioned twice or more in different locations in this specification do not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of the application can be appropriately combined.

[0071] In some embodiments, numbers describing the quantity of components and attributes are used. It should be understood that such numbers used in the description of embodiments are modified in some examples with the terms "approximately," "approximately," or "generally." Unless otherwise stated, "approximately," "approximately," or "generally" indicates that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in the specification and claims are approximate values, which may be changed depending on the characteristics required by individual embodiments. In some embodiments, numerical parameters should take into account specified significant digits and employ a general method of digit reservation. Although the numerical ranges and parameters used to confirm their breadth of range in some embodiments of this application are approximate values, in specific embodiments, such numerical values ​​are set as precisely as feasible.

[0072] While the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Any variations and modifications can be made by those skilled in the art without departing from the spirit and scope of the invention. Therefore, any modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention, without departing from the scope of the invention, fall within the protection scope defined by the claims of the present invention.

Claims

1. A staggered stator structure, the stator structure comprising a plurality of circumferentially distributed adjustable stator blades, each of the adjustable stator blades comprising a rotating shaft, a rocker arm assembly, and a blade body, characterized in that, The axial positions of each of the aforementioned rotation axes are staggered.

2. The staggered cascade structure as described in claim 1, characterized in that, The axial positions of each blade body are staggered.

3. The staggered cascade structure as described in claim 1, characterized in that, Each of the adjustable stator blades has the same axial position.

4. The staggered cascade structure as described in any one of claims 1-3, characterized in that, The adjustable stator blade also includes a frustum disposed at the end of the blade body, the axial positions of the frustums being staggered.

5. The staggered cascade structure as described in claim 1, characterized in that, The blade body includes a root portion and a tip portion. The tip portion is connected to the rocker arm assembly. The root portion forms a gap with the rotor disk, and the gap value from the leading edge to the trailing edge of the root portion is the same, so as to form a cantilevered adjustable stator blade.

6. The staggered cascade structure as described in claim 5, characterized in that, The gap value is 0.2 to 0.6 mm.

7. The staggered cascade structure as described in claim 1, characterized in that, The axial deviation of the rotating shaft is 1mm to 50mm.

8. The staggered cascade structure as described in claim 1, characterized in that, The blade consistency of this staggered cascade structure is greater than 1.

5.

9. A compressor, including an adjustable inlet stator, characterized in that, The adjustable inlet stator adopts the staggered cascade structure as described in any one of claims 1-8.

10. An aircraft engine, characterized in that, Including the compressor as described in claim 9.

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