Circumferential large-interval small-hole distributed self-circulation treatment casing for stability expansion of aviation compressor with splitter blades

Abstract

The invention relates to a distributed self-circulation treatment casing with large circumferential intervals and small holes for stability expansion of an aviation compressor with splitter blades. Gas in a groove cavity is driven to flow by utilizing pressure difference between a main blade of a compressor rotor casing, a first jet hole structure and a second jet hole structure at the front edge of the splitter blades and a suction groove structure at the tail edge of a rotor; due to the fact that relative movement exists between the casing and the rotor, airflow in the first jet hole structure and the second jet hole structure periodically sweeps a working impeller runner of the gas compressor, and the periodic blowing effect on flowing in the gas compressor can be achieved. The influence range and strength of adverse low-energy flows (leakage vortexes, wake vortexes and the like) near front edge blade tips of main blades and splitter blades of a working impeller of the gas compressor are restrained; and meanwhile, a low-pressure source in the suction groove has a suction effect on the flow channel, the influence range and strength of adverse low-energy flow (wake vortex and the like) of the trailing edge are restrained, and the stable working margin is remarkably expanded under the condition that the maximum pressure ratio and efficiency of the gas compressor are not influenced.

Description

Technical Field

[0001] This invention relates to the field of aviation power plant technology, and in particular to a circumferentially large-spaced, small-aperture distributed self-circulating processing casing for stabilizing aviation compressors with split-flow blades. Background Technology

[0002] In the field of aero-engines, the aero-compressor is a key component, and its performance directly affects the energy conversion efficiency and stability of the aero-engine system. For some scenarios requiring small turbine engines with high pressure ratios and high efficiency, aero-compressors with split vanes can meet the requirements of compactness and high performance. Aero-compressors with split vanes can also adapt to gas compression needs under different operating conditions, improve the system's operating efficiency under partial load conditions, and enhance the system's reliability.

[0003] Existing research on splitter blades has effectively improved the thrust-to-weight ratio and reduced fuel consumption of engines with splitter blades. However, due to the complexity of the flow at the compressor rotor tip, high pressure ratio and high efficiency of the compressor often contradict high stability margin. Splitter blade design alone is insufficient to further alleviate this contradiction. Therefore, it is necessary to apply effective flow control to the internal flow of the compressor based on existing research results, especially by fully utilizing the internal flow mechanism of the compressor. This can be achieved through a self-circulating regulating mechanism independent of the external environment of the aero-engine, while simultaneously utilizing and improving flow structures that are detrimental to its performance. The goal is to further expand the stability margin of the splitter blade aero-compressor and broaden the operating envelope of the aero-engine while maintaining high pressure ratio and high efficiency.

[0004] For compressor rotors with split blades, the leakage flow at the tips of the main blades and split blades has a significant impact on their stable operation. The rotational stall problem caused by the overflow at the leading edge of the rotor impeller is a key factor restricting the stable operating range of aero-engines. By introducing periodic blowing excitation near the trailing edge of the working impeller and suction excitation near the trailing edge of the working impeller, the leakage flow at the rotor tips can be effectively improved, the rotor stall margin can be increased, and a better stability enhancement effect can be achieved.

[0005] Casing treatment is a common method to increase compressor stability margin. Based on the characteristics of the excitation applied to the flow field by the casing treatment structure, it is divided into casing treatment based on steady flow control and casing treatment based on unsteady flow control. The former has been extensively studied, and various treatment methods have been designed to effectively increase stability margin. Casing treatment based on unsteady flow control can apply excitation to the flow field at a certain frequency. When the excitation frequency is close to the frequency of the main vortex structure in the flow field, a certain degree of coherence can occur, ordering the corresponding quasi-ordered structures in the flow field, achieving the goal of improving the flow field with relatively small energy expenditure. Furthermore, since unsteady flow control requires an order of magnitude less excitation intensity to achieve the same control effect compared to steady flow control, its impact on the mainstream is smaller, and its impact on the efficiency of compressors with splitter blades is also smaller.

[0006] Therefore, the compressor self-circulating casing treatment method based on unsteady flow control has great advantages in improving compressor stability margin, and can be implemented in a simple, reliable and practical way. Summary of the Invention

[0007] The purpose of this invention is to provide a circumferentially large-spacing, small-aperture distributed self-circulating processing casing for expanding the stability of an aero-engine compressor with split-flow blades. Its purpose is to improve the stability margin while maintaining the compressor's maximum pressure ratio and efficiency essentially unchanged based on the unsteady control mechanism, thereby effectively expanding the operating envelope of the aero-engine.

[0008] To achieve the above objectives, the technical solution proposed by this invention is as follows: A circumferentially large-spacing, small-aperture distributed self-circulating processing casing for stabilizing an aero-compressor with split-flow blades, characterized in that it comprises: a casing, a suction groove structure, a first jet hole structure, a second jet hole structure, and a groove cavity; The casing includes an outer wall and an inner wall, which are arranged at intervals. Multiple slots are provided between the outer wall and the inner wall. The cross-sectional area of ​​the airflow direction of the multiple slots remains unchanged or gradually decreases. A working impeller is provided in the inner cavity of the casing. A suction groove structure is opened on the inner wall of the casing, and the suction groove structure is connected to the corresponding slot. The working impeller includes multiple main blades and multiple branch blades, with the multiple branch blades inserted one by one between two main blades; The first jet hole structure is inclinedly opened on the inner wall of the casing and is located downstream of the leading edge of the main blade. The second jet hole structure is inclinedly opened on the inner wall of the casing and is located downstream of the leading edge of the splitter blade. The first jet hole structure and the second jet hole structure are arranged alternately with the suction groove structure and are both connected to the groove cavity. The first jet hole structure and the second jet hole structure have a large interval along the circumferential direction. The compressor's circumferentially large-spaced, small-aperture distributed self-circulating pulse-excited casing utilizes the pressure difference between the first jet hole structure, the second jet hole structure, and the suction groove structure to drive the gas flow within the groove cavity. Due to the relative motion between the casing and the rotor, the airflow in the first and second jet hole structures periodically sweeps the compressor's working impeller flow channel, achieving a periodic blowing effect on the flow within the compressor. Simultaneously, the low-pressure source within the suction groove structure creates a suction effect on the flow field at the trailing edge of the compressor rotor.

[0009] Preferably, the suction groove structure is provided with N3 suction channels, and the distance between the suction groove structure and the end of the working impeller is L3. The N3 suction channels are evenly opened on the inner wall surface at a distance of L3 from the trailing edge of the main blade. The L3 distance section is the main influence area of ​​the wake vortex. The pressure inside the compressor at the location of the suction groove structure is higher than the pressure inside the groove cavity, thereby achieving an outward suction excitation effect on the airflow in the working impeller blade channel inside the compressor.

[0010] Preferably, the number of main blades is Z1, which is determined by the existing number of compressor main blades, and N3 / Z1 is 0.8 to 1.2; the axial chord length of the working impeller tip is L, which is determined by the existing axial chord length of the compressor working impeller tip, and L3 / L is -0.1 to 0.1.

[0011] Preferably, the cross-sectional area of ​​a single suction channel is A3, the radius of the inner wall of the working impeller outlet casing is R2, R2 is determined by the existing radius of the inner wall of the compressor working impeller outlet casing, B=0.02R2~0.04R2, η3=0.5~1.3, then the area of ​​a single suction channel is A3=2η3π(R2)B / Z1.

[0012] Preferably, the grooving direction of the suction channel is as follows: on the meridional plane, the direction pointing to the mainstream is positive, and the angle between the grooving direction on the casing and the outer normal F of the casing is 0° to 60°; on the cross-section, the direction pointing to the blade tip rotational linear velocity at that location is positive, and the angle between the grooving direction on the casing and the outer normal F of the casing is -45° to 45°.

[0013] Preferably, the first jet hole structure has N1 first jet holes uniformly formed on the inner wall of the casing at a distance L1 from the leading edge of the main blade, and the second jet hole structure has N2 second jet holes uniformly formed on the inner wall of the casing at a distance L2 from the leading edge of the split blade. In the L1 distance section, the evolution of the unfavorable low-energy flow near the tip of the main blade of the working impeller is in the initial growth stage, and in the L2 distance section, the evolution of the unfavorable low-energy flow near the tip of the split blade of the working impeller is in the initial growth stage. The internal pressure of the compressor at the locations of the first jet hole structure and the second jet hole structure is lower than the internal pressure of the slot cavity, thereby achieving a periodic inward blowing excitation effect on the airflow in the working impeller blade channel inside the compressor.

[0014] Preferably, the number of N1 first jet orifices is N1 / Z1, which is 0.8 to 1.2, the number of multiple split vanes is Z2, which is determined by the existing number of compressor split vanes, and the number of N2 second jet orifices is N2 / (Z1+Z2), which is 0.8 to 1.2.

[0015] Preferably, let A1 be the area of ​​a single first jet orifice and a single second jet orifice, let R3 be the inlet hub radius of the working impeller, R3 is determined by the existing inlet hub radius of the compressor working impeller, and let H be the inlet blade height of the main blade of the working impeller, H is determined by the existing inlet blade height of the main blade of the compressor working impeller. Then the inlet area of ​​the working impeller is S = π * ((R3 + H)). 2 -R3 2 A1 / S is taken as 0.02% to 0.2%; the opening angle is: on the meridional plane, with the direction pointing to the mainstream as positive, the angle between the opening direction on the casing and the outer normal F of the casing is -40° to -70°; on the cross section, with the linear velocity of the blade tip pointing to that location as positive, the angle between the opening direction on the casing and the outer normal of the casing is -50° to -80°.

[0016] Preferably, the suction groove structure, the first jet orifice, and the second jet orifice are all elliptical, rectangular, or superelliptical in shape. When the orifice is elliptical, the ratio of its major semi-axis b to its minor semi-axis a is 1.0 to 5.0, and its area is πab. When the orifice is rectangular, the ratio of its long side c to its short side d is 1.0 to 5.0, and it may also have a small radius rounded corner with radius r. The ratio of the rounded corner radius r to the short side d is 0.1 to 0.25, and its area is cd-4r. 2 +πr 2 When the shape of the hole is a hyperellipse, (x / a) n +(y / b) n =1, its major semi-axis b to minor semi-axis a ratio is 1.0 to 5.0, its exponent n is 2.0 to 10.0, and its area is 4ab*(Γ(1+1 / n)). 2 / Γ(1+2 / n), Γ(z) is t z-1 / e t Integrating t from 0 to positive infinity, when z is an integer, Γ(z) = (z-1)!.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. By utilizing the relative motion between the compressor casing and rotor, and the pressure difference between the first jet hole structure, the second jet hole structure, and the suction groove structure, the gas flow between the suction groove structure and the first and second jet hole structures is driven. The low-pressure source in the suction groove structure periodically sweeps the compressor rotor flow channel to achieve periodic suction of the flow inside the compressor. The airflow in the first and second jet hole structures periodically sweeps the compressor working impeller flow channel to achieve periodic blowing of the flow inside the compressor. At the same time, it suppresses the influence range and intensity of unfavorable low-energy flows (leakage vortices, wake vortices, etc.) near the tips of the compressor working impeller main blades and split blades, thereby significantly expanding the stable operating margin of the compressor and effectively expanding the working envelope of the aero-engine.

[0018] 2. By using the first and second jet holes on the stationary casing, the flow field at the leading edge of the rotor is periodically jetted in the rotating coordinate system, achieving a high-frequency dynamic excitation effect. Utilizing the unsteady excitation effect of "stopping the engine by stopping it", the total area of ​​the openings on the casing is more than an order of magnitude smaller than that of a typical processing casing, resulting in a smaller impact on compressor efficiency. Furthermore, the structure is simple and easy to implement.

[0019] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0020] The present invention will be further described below with reference to the accompanying drawings and embodiments; Figure 1 This is a cross-sectional structural diagram of the present invention.

[0021] Figure 2 This is another cross-sectional structural schematic diagram of the present invention.

[0022] Figure 3 This is a schematic diagram of one of the structures of the suction channel, the first jet orifice, and the hole in the second jet orifice in this invention.

[0023] Figure 4 This is a schematic diagram of the second structure of the suction channel, the first jet orifice, and the hole in the second jet orifice in this invention.

[0024] Figure 5 This is a schematic diagram of the three structures of the suction channel, the first jet orifice, and the second jet orifice in this invention.

[0025] Figure 6 This is a schematic diagram illustrating the flow control principle of the first and second jet orifices in this invention.

[0026] Figure 7 This is a schematic cross-sectional view of the cross-section where the suction groove structure is located in this invention.

[0027] Figure 8 This is a schematic cross-sectional view of the cross-section of the first and second jet holes in this invention.

[0028] The following labels in the attached diagram are: 1. Casing; 11. Impeller; 111. Main blade; 112. Diverter blade; 2. Suction groove structure; 21. Suction through groove; 3. First jet hole structure; 31. First jet through hole; 4. Second jet hole structure; 41. Second jet through hole; 5. Groove cavity; 6. Leakage vortex; F. Outer normal of the casing; G. Main flow direction; J. Slotting direction of the suction channel; K. Opening direction of the first jet orifice; P. Opening direction of the second jet orifice; Q. Rotation direction of the working impeller; L1, distance between the center of the first jet passage and the leading edge of the main blade; L2, distance between the center of the second jet passage and the leading edge of the main blade; L3, distance between the suction groove structure and the end of the working impeller; α1, angle between the slotting direction of the suction groove and the outer normal of the casing; β, angle between the opening directions of the first and second jet passages and the outer normal of the casing; β1, angle between the opening directions of the first and second jet passages on the meridional plane and the outer normal of the casing; β2, angle between the opening directions of the first and second jet passages on the cross-section. Angle between the hole direction and the outer normal of the casing; R2, radius of the inner wall of the casing at the impeller outlet; R3, radius of the impeller inlet hub; H, inlet blade height of the main blade; V, (dashed line) hyperellipse with n=4; W, (dashed line) hyperellipse with n=8; a, when the shape of the suction groove structure, the first jet orifice, and the second jet orifice are elliptical or hyperelliptical, their minor axis; b, when the shape of the suction groove structure, the first jet orifice, and the second jet orifice are elliptical or hyperelliptical, their major axis; c, when the shape of the suction groove structure, the first jet orifice, and the second jet orifice are rectangular, their long side; d, when the shape of the suction groove structure, the first jet orifice, and the second jet orifice are rectangular, their short side; r, when the shape of the suction groove structure, the first jet orifice, and the second jet orifice are rectangular, their fillet radius. Detailed Implementation

[0029] This section will describe in detail specific embodiments of the present invention. Preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the drawings is to supplement the textual description with graphics, so that people can intuitively and vividly understand each technical feature and overall technical solution of the present invention, but they should not be construed as limiting the scope of protection of the present invention.

[0030] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and 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. Therefore, they should not be construed as limiting this invention.

[0031] In the description of this invention, terms such as greater than, less than, and exceeding are understood to exclude the stated number, while terms such as above, below, and within are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0032] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0033] Reference Figures 1-8 This invention provides a circumferentially spaced, small-aperture distributed self-circulating processing casing for stabilization of an aero-compressor with splitter blades, comprising a casing 1, a suction groove structure 2, a first jet orifice structure 3, a second jet orifice structure 4, and a cavity 5; the casing 1 includes an outer wall surface and an inner wall surface, which are arranged at intervals, and multiple cavities 5 are provided between the outer wall surface and the inner wall surface. The cross-sectional area of ​​the multiple cavities 5 in the airflow direction remains constant or gradually decreases. A working impeller 11 is provided in the inner cavity of the casing 1, and the suction groove structure 2 is formed on the inner wall surface of the casing 1, and the suction groove structure 2 is correspondingly connected to the cavity 5; the working impeller... 11 includes multiple main blades 111 and multiple diverter blades 112, with the multiple diverter blades 112 inserted one by one between two main blades 111; the first jet hole structure 3 is inclinedly opened on the inner wall of the casing 1 and is located downstream of the leading edge of the main blade 111; the second jet hole structure 4 is inclinedly opened on the inner wall of the casing 1 and is located downstream of the leading edge of the diverter blade 112; the first jet hole structure 3 and the second jet hole structure 4 are arranged at intervals with the suction groove structure 2 and are all connected to the groove cavity 5; the first jet hole structure 3 and the second jet hole structure 4 have a large interval along the circumferential direction. In compressors, traditional casing treatments often involve creating numerous densely packed holes and multiple circumferential grooves of a certain length. In this invention, the first jet hole structure 3 and the second jet hole structure 4 have a larger circumferential spacing compared to traditional casing treatments. Utilizing the relative motion between the compressor casing 1 and the rotor, and the pressure difference between the first jet hole structure 3, the second jet hole structure 4, and the suction groove structure 2, the gas flow between the suction groove structure 2 and the first jet hole structure 3 and the second jet hole structure 4 is driven. The low-pressure source within the suction groove structure 2 achieves periodic suction of the compressor's internal flow by periodically sweeping the compressor's rotor flow channel. The first jet hole structure... The airflow within structure 3 and the second jet hole structure 4 periodically sweeps the flow channel of the compressor impeller 11 to achieve a periodic blowing effect on the flow inside the compressor. This can simultaneously suppress the influence range and intensity of unfavorable low-energy flows (leakage vortices, blade back separation vortices, etc.) near the tips of the main blades 111 and the split blades 112 of the compressor impeller 11, thereby significantly expanding the stable operating margin of the compressor and effectively expanding the operating envelope of the aero-engine. At the same time, due to the ingenious use of the unsteady excitation effect of "static braking", the total area of ​​the openings on the casing 1 is more than an order of magnitude smaller than that of a typical handling casing 1, which has a smaller impact on the compressor efficiency. Moreover, the structure is simple and easy to implement.

[0034] The suction groove structure 2 is provided with N3 suction channels 21. The distance between the suction groove structure 2 and the end of the working impeller 11 is L3. The N3 suction channels 21 are evenly opened on the inner wall surface at a distance of L3 from the trailing edge of the main blade 111. The L3 distance section is the main influence area of ​​the wake vortex. The pressure inside the compressor at the location of the suction groove structure 2 is higher than the pressure inside the groove cavity 5. This achieves a periodic outward suction excitation effect on the airflow in the blade channel of the working impeller 11 inside the compressor. To achieve a periodic blowing effect, the number of multiple main blades 111 is denoted as Z1, and the number of multiple branch blades 112 is denoted as Z2. The number of N3 suction channels 21 in the suction channel structure 2 is determined by referring to the existing number of compressor main blades 111 Z1 and the number of branch blades 112 Z2, and N3 / Z1 is taken as 0.8 to 1.2.

[0035] In the suction groove structure 2, the N3 suction grooves 21 are evenly distributed on the meridional plane. The center of each of the N3 suction grooves 21 on the casing 1 is L3 away from the trailing edge of the working impeller 11 blade. Let L be the axial chord length of the working impeller 11 blade tip. L is determined by the existing axial chord length of the compressor working impeller 11 blade tip. The range of L3 / L is -0.1 to 0.1. The area of ​​the N3 suction grooves 21 determines the suction volume of the casing 1. The area of ​​a single suction groove 21 is A3. Let R2 be the radius of the inner wall surface of the casing 1 at the outlet of the working impeller 11. R2 is determined by the existing radius of the inner wall surface of the casing 1 at the outlet of the compressor working impeller 11. B = 0.02R2 ~ 0.04R2, η3 = 0.5 ~ 1.3. Then the area of ​​a single suction groove 21 is A3 = 2η3π(R2)B / Z1.

[0036] To utilize airflow energy more effectively, on the meridional plane, the slotting direction of the N3 suction channels 21 is positive, pointing towards the mainstream direction G, and the angle between the slotting direction on the casing 1 and the outer normal F of the casing ranges from 35° to 65°; on the cross-section, the slotting direction of the N3 suction channels 21 is positive, pointing towards the blade tip rotational velocity at that location, and the angle between the slotting direction on the casing 1 and the outer normal F of the casing ranges from 45° to 75°.

[0037] To achieve the effect of periodic blowing excitation through openings on the inner wall of the compressor casing 1, a first jet hole structure 3 with a large circumferential interval is provided near the leading edge of the main blade 111 of the working impeller 11, and a second jet hole structure 4 with a large circumferential interval is provided near the leading edge of the split blade 112 of the working impeller 11. In the L1 distance range, the evolution of unfavorable low-energy flow near the tip of the main blade 111 of the working impeller 11 is in the initial growth stage, and in the L2 distance range, the evolution of unfavorable low-energy flow near the tip of the split blade 112 of the working impeller 11 is in the initial growth stage. The internal pressure of the compressor at the locations of the first jet hole structure 3 and the second jet hole structure 4 is lower than the internal pressure of the slot cavity 5, thereby achieving a relatively periodic inward blowing excitation effect on the airflow in the blade channel of the working impeller 11 inside the compressor.

[0038] To achieve a periodic blowing effect, the number of N1 first jet orifices 31 is selected with reference to the number of main blades 111 of the compressor impeller 11, and the number of compressor main blades 111 is denoted as Z1. Z1 is determined by the existing number of compressor main blades 111, and the range of N1 / Z1 is 0.8 to 1.2. The number of N2 second jet orifices 41 is selected according to the number of main blades 111 of the compressor impeller 11, and the number of compressor main blades 111 is denoted as Z2. Z2 is determined by the existing number of compressor main blades 111. 1. The number is determined, and the range of N2 / Z2 is 0.8 to 1.2; further, on the meridional plane, the distance between the center of the first jet hole 31 on the casing 1 and the leading edge of the main blade 111 of the working impeller 11 is L1; the distance between the center of the second jet hole 41 on the casing 1 and the leading edge of the main blade 111 of the working impeller 11 is L2; ​​let the axial chord length of the blade tip of the working impeller 11 be L, which is determined by the existing axial chord length of the blade tip of the compressor working impeller 11, and take L1 / L as -0.1 to 0.1; L2 / L as -0.1 to 0.1.

[0039] In a single first jet orifice 31 or a single second jet orifice 41, the blowing volume depends on the area of ​​the single first jet orifice 31 or the single second jet orifice 41 corresponding to the inner wall surface of the casing 1. Let the area of ​​the single first jet orifice 31 or the single second jet orifice 41 be A1, and let the inlet hub radius of the working impeller 11 be R3. R3 is determined by the existing inlet hub radius of the compressor working impeller 11, and the inlet blade height of the main blade 111 of the working impeller 11 is H. H is determined by the existing inlet blade height of the main blade 111 of the compressor working impeller 11. Then the inlet area of ​​the working impeller 11 is S = π * ((R3 + H)). 2 -R3 2 The range of A1 / S is 0.02% to 0.2%. In most cases, the compressor stability margin is better when the orifice area is near the middle value of the given range, and the compressor efficiency is higher when the orifice area is near the smaller value. To more effectively excite the impeller airflow, on the meridional plane, the opening angles of the first jet orifice 31 and the second jet orifice 41 are both positive, pointing towards the mainstream direction G, and the angle between the opening direction on the casing 1 and the outer normal F of the casing ranges from -40° to -70°; on the cross-section, the angle between the blade tip rotational linear velocity pointing to that location is positive, and the angle between the opening direction on the casing 1 and the outer normal F of the casing ranges from -50° to -80°.

[0040] To more effectively excite the impeller airflow, when the first jet orifice 31, the second jet orifice 41, and the suction channel 21 are elliptical in shape, the ratio of their major semi-axis b to their minor semi-axis a ranges from 1.0 to 5.0, and their area is πab. When the first jet orifice 31, the second jet orifice 41, and the suction channel 21 are rectangular in shape, the ratio of their long side c to their short side d ranges from 1.0 to 5.0. Such rectangles can have a small radius rounded corner (radius r), and their area is cd-4r. 2 +πr 2 When the shapes of the first jet orifice 31, the second jet orifice 41, and the suction channel 21 are determined by formula (x / a) n +(y / b) n When the hyperellipse is generated by =1, the ratio of its major semi-axis b to its minor semi-axis a ranges from 1.0 to 5.0, its exponent n ranges from 2.0 to 10.0, and its area is 4ab*(Γ(1+1 / n)). 2 / Γ(1+2 / n),Γ(z) is t z-1 / e t Integrating t from 0 to positive infinity, when z is an integer, Γ(z) = (z-1)!; For the above three hole types, in most cases, the ratio of their major and minor semi-axis (long and short sides) is better when it is near the middle value of a given range; At the same time, from the inner wall surface of the cavity 5 to the inner wall surface of the casing 1, the cross-sectional area of ​​the holes of the first jet hole 31, the second jet hole 41 and the suction channel 21 remains unchanged or gradually decreases; In most cases, the holes of the first jet hole 31, the second jet hole 41 and the suction channel 21 can be straight holes.

[0041] Example: Taking the centrifugal compressor of a micro turbojet engine as an example Reference Figures 1-8This invention provides a circumferentially spaced, small-aperture distributed self-circulating processing casing for stabilization of an aero-compressor with splitter blades, comprising a casing 1, a suction groove structure 2, a first jet orifice structure 3, a second jet orifice structure 4, and a cavity 5; the casing 1 includes an outer wall surface and an inner wall surface, which are arranged at intervals, and multiple cavities 5 are provided between the outer wall surface and the inner wall surface. The cross-sectional area of ​​the multiple cavities 5 in the airflow direction remains constant or gradually decreases. A working impeller 11 is provided in the inner cavity of the casing 1, and the suction groove structure 2 is formed on the inner wall surface of the casing 1, and the suction groove structure 2 is correspondingly connected to the cavity 5; the working impeller... 11 includes multiple main blades 111 and multiple diverter blades 112, with the multiple diverter blades 112 inserted one by one between two main blades 111; the first jet hole structure 3 is inclinedly opened on the inner wall of the casing 1 and is located downstream of the leading edge of the main blade 111; the second jet hole structure 4 is inclinedly opened on the inner wall of the casing 1 and is located downstream of the leading edge of the diverter blade 112; the first jet hole structure 3 and the second jet hole structure 4 are arranged at intervals with the suction groove structure 2 and are all connected to the groove cavity 5; the first jet hole structure 3 and the second jet hole structure 4 have a large interval along the circumferential direction. The suction groove structure 2 is provided with N3 suction channels 21. The distance between the suction groove structure 2 and the end of the working impeller 11 is L3. The N3 suction channels 21 are evenly opened on the inner wall surface at a distance of L3 from the trailing edge of the main blade 111. The L3 distance section is the main influence area of ​​the wake vortex. The internal pressure of the centrifugal compressor at the location of the suction groove structure 2 is higher than the internal pressure of the groove cavity 5. This achieves a periodic outward suction excitation effect on the airflow in the blade channel of the working impeller 11 inside the centrifugal compressor.

[0042] The suction channel 21 is a straight hole with an elliptical cross-section, with a major semi-axis a=1.59mm, a minor semi-axis b=0.80mm, a major-minor semi-axis ratio a / b=2.0, and n=2.0; the first jet hole 31 and the second jet hole 41 are both straight holes with a rounded rectangular cross-section, with a major side c=2.00mm, a minor side d=1.00mm, a major-minor side ratio c / d=2.0, a chamfer radius r=0.17mm, and a chamfer radius r to minor side d ratio of 0.17.

[0043] The number of suction channels 21 is N3=8, the number of existing centrifugal compressor main blades 111 is Z=8, and N1 / Z is 1.

[0044] On the meridional plane, the distance between the center of the suction channel 21 on the casing 1 and the trailing edge of the blade of the working impeller 11 is L3=3.14mm. The axial chord length of the blade tip of the centrifugal compressor working impeller 11 is L=31.43mm, and L3 / L is 0.1.

[0045] The suction capacity of the slotted casing 1 depends on the area of ​​the suction slot 21 on the inner wall of casing 1. The radius of the inner wall of casing 1 at the outlet of the working impeller 11 is R2 = 11 mm, and the area of ​​a single suction slot 21 is A3 = πab = 2η3π(R2)B / Z1 = 3.98 mm. 2 .

[0046] On the meridional plane, with the direction pointing to the mainstream G as positive, the angle α1 between the slotting direction of the suction groove 21 on the casing 1 and the outer normal F of the casing is 50°; on the cross-section, with the linear velocity of the blade tip pointing to that location as positive, the angle α2 between the slotting direction of the suction groove 21 on the casing 1 and the outer normal F of the casing is 60°.

[0047] N1 first jet orifices 31 are opened around the inner wall of the casing 1 at a certain distance L1 from the leading edge of the blade downstream of the main blade 111 of the working impeller 11. N2 second jet orifices 41 are opened in the casing 1 at a certain distance L2 from the leading edge of the blade downstream of the inlet of the split blade 112 of the working impeller 11. In the L1 distance range, the evolution of unfavorable low-energy flow near the tip of the main blade 111 of the working impeller 11 is in the initial growth stage. In the L2 distance range, the evolution of unfavorable low-energy flow near the tip of the split blade 112 of the working impeller 11 is in the initial growth stage. The internal pressure of the centrifugal compressor at the locations of the first jet orifice structure 3 and the second jet orifice structure 4 is lower than the internal pressure of the slot cavity 5. This achieves a relatively periodic inward blowing excitation effect on the airflow in the rotor blade channel of the working impeller 11 inside the centrifugal compressor.

[0048] The number of first jet orifices 31 is N1=8, the number of existing centrifugal compressor main blades 111 is Z1=8, and N1 / Z1 is 1.

[0049] The number of second jet orifices 41 is N2=8, the number of existing centrifugal compressor splitter blades 112 is Z2=8, and N2 / Z2 is 1.

[0050] On the meridional plane, the distance between the center of the first jet hole 31 on the casing 1 and the leading edge of the main blade 111 of the working impeller 11 is L1=3.14mm.

[0051] On the meridional plane, the distance between the center of the second jet hole 41 on the casing 1 and the leading edge of the main blade 111 of the working impeller 11 is L2=3.14mm.

[0052] The area of ​​each individual first jet orifice 31 and second jet orifice 41 is A1 = cd - 4r. 2 +πr 2 =1.97mm 2The inlet hub radius of the working impeller 11 is R3 = 8mm, and the inlet blade height of the main blade 111 of the working impeller 11 is H = 18.9mm. Therefore, the inlet area of ​​the working impeller 11 is S = π * (H + R3). 2 -R3 2 =2072.2mm 2 The A1 / S ratio is 0.09%.

[0053] On the meridional plane, taking the direction pointing to the mainstream G as positive, the angle β1 between the opening direction of the first jet flow hole 31 and the second jet flow hole 41 on the casing 1 and the outer normal F of the casing is -60°; on the cross-section, taking the rotational linear velocity of the blade tip pointing to that location as positive, the angle β2 between the opening direction of the first jet flow hole 31 and the second jet flow hole 41 on the casing 1 and the outer normal F of the casing is -65°.

[0054] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple 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 present invention shall still fall within the scope of the present invention.

Claims

1. A circumferentially large-spaced, small-aperture distributed self-circulating processing casing for stabilization of an aero-compressor with splitter blades, characterized in that, include: The casing (1), the suction groove structure (2), the first jet hole structure (3), the second jet hole structure (4), and the groove cavity (5); The casing (1) includes an outer wall surface and an inner wall surface, which are arranged at intervals. Multiple slots (5) are provided between the outer wall surface and the inner wall surface. The cross-sectional area of ​​the multiple slots (5) in the airflow direction remains unchanged or gradually decreases. A working impeller (11) is provided in the inner cavity of the casing (1). A suction groove structure (2) is opened on the inner wall surface of the casing (1), and the suction groove structure (2) is connected to the slots (5). The working impeller (11) includes multiple main blades (111) and multiple branch blades (112), with the multiple branch blades (112) inserted one by one between two main blades (111); The first jet hole structure (3) is inclinedly opened on the inner wall of the casing (1) and is located downstream of the leading edge of the main blade (111). The second jet hole structure (4) is inclinedly opened on the inner wall of the casing (1) and is located downstream of the leading edge of the splitter blade (112). The first jet hole structure (3) and the second jet hole structure (4) are arranged at intervals with the suction groove structure (2) and are connected to the groove cavity (5). The first jet hole structure (3) and the second jet hole structure (4) have a large interval along the circumferential direction. The compressor circumferential large-interval small-aperture distributed self-circulating pulse excitation casing (1) uses the pressure difference between the first jet hole structure (3), the second jet hole structure (4) and the suction groove structure (2) to drive the gas flow in the groove cavity (5). Due to the relative motion between the casing (1) and the rotor, the airflow in the first jet hole structure (3) and the second jet hole structure (4) periodically sweeps the flow channel of the compressor working impeller (11), which can realize the periodic blowing effect on the flow inside the compressor. At the same time, the low pressure source in the suction groove structure (2) forms a suction effect on the flow field at the tail edge of the compressor rotor.

2. The circumferentially large-spacing, small-aperture distributed self-circulating processing casing for stabilization of an aero-compressor with splitter blades according to claim 1, characterized in that, The suction groove structure (2) is provided with N3 suction channels (21). The suction groove structure (2) is L3 away from the end of the working impeller (11). The N3 suction channels (21) are evenly opened on the inner wall surface at a distance of L3 from the trailing edge of the main blade (111). The L3 distance section is the main area affected by the wake vortex. The pressure inside the compressor at the location of the suction groove structure (2) is higher than the pressure inside the groove cavity (5). This achieves the effect of applying an outward suction excitation to the airflow in the blade channel of the working impeller (11) inside the compressor.

3. A circumferentially large-spaced, small-aperture distributed self-circulating processing casing for stabilization of an aero-compressor with splitter blades according to claim 2, characterized in that, The number of the multiple main blades (111) is Z1, which is determined by the number of existing compressor main blades (111), and N3 / Z1 is 0.8 to 1.2; the axial chord length of the tip of the working impeller (11) is L, which is determined by the existing axial chord length of the tip of the compressor working impeller (11), and L3 / L is -0.1 to 0.

1.

4. A circumferentially large-spaced, small-aperture distributed self-circulating processing casing for stabilization of an aero-compressor with splitter blades according to claim 2, characterized in that, The cross-sectional area of ​​a single suction channel (21) is A3, and the radius of the inner wall of the outlet casing (1) of the working impeller (11) is R2. R2 is determined by the existing inner wall radius of the outlet casing (1) of the compressor working impeller (11). B = 0.02R2 ~ 0.04R2, η3 = 0.5 ~ 1.

3. Then the area of ​​a single suction channel (21) is A3 = 2η3π(R2)B / Z1.

5. A circumferentially large-spaced, small-aperture distributed self-circulating processing casing for stabilization of an aero-compressor with splitter blades according to claim 2, characterized in that, The grooving direction of the suction channel (21) is as follows: on the meridional plane, the direction pointing to the mainstream is positive, and the angle between the grooving direction on the casing (1) and the outer normal of the casing (1) is 0° to 60°; on the cross-section, the direction pointing to the blade tip rotation linear velocity is positive, and the angle between the grooving direction on the casing (1) and the outer normal of the casing (1) is -45° to 45°.

6. A circumferentially large-spaced, small-aperture distributed self-circulating processing casing for stabilization of an aero-compressor with splitter blades according to claim 1, characterized in that, The first jet hole structure (3) has N1 first jet holes (31) uniformly opened on the inner wall surface of the casing (1) at a distance L1 from the leading edge of the main blade (111). The second jet hole structure (4) has N2 second jet holes (41) uniformly opened on the inner wall surface of the casing (1) at a distance L2 from the leading edge of the split blade (112). The evolution of unfavorable low-energy flow near the tip of the main blade (111) of the working impeller (11) in the L1 distance section is in the initial growth stage. The evolution of unfavorable low-energy flow near the tip of the split blade (112) of the working impeller (11) in the L2 distance section is in the initial growth stage. The internal pressure of the compressor at the location of the first jet hole structure (3) and the second jet hole structure (4) is lower than the internal pressure of the slot cavity (5), thereby achieving the excitation effect of periodically blowing air into the airflow in the blade channel of the working impeller (11) inside the compressor.

7. A circumferentially large-spaced, small-aperture distributed self-circulating processing casing for stabilization of an aero-compressor with splitter blades according to claim 6, characterized in that, The number of N1 first jet orifices (31) is N1 / Z1, which is 0.8 to 1.

2. The number of multiple split vanes (112) is Z2, which is determined by the number of existing compressor split vanes (112). The number of N2 second jet orifices (41) is N2 / (Z1+Z2), which is 0.8 to 1.

2.

8. A circumferentially large-spacing, small-aperture distributed self-circulating processing casing for stabilization of an aero-compressor with splitter blades according to claim 6, characterized in that, Let the area of ​​a single first jet orifice (31) and a single second jet orifice (41) be A1. Let the inlet hub radius of the working impeller (11) be R3, which is determined by the existing inlet hub radius of the compressor working impeller (11). Let the inlet blade height of the main blade (111) of the working impeller (11) be H, which is determined by the existing inlet blade height of the main blade (111) of the compressor working impeller (11). Then the inlet area of ​​the working impeller (11) is S = π * ((R3 + H)). 2 -R3 2 ), take A1 / S as 0.02%~0.2%; the opening angle is: on the meridional plane, with the direction pointing to the mainstream as positive, the angle between the opening direction on the casing (1) and the outer normal of the casing (1) is -40°~-70°; on the cross section, with the linear velocity of the blade tip rotation pointing to that point as positive, the angle between the opening direction on the casing (1) and the outer normal of the casing (1) is -50°~-80°.

9. A circumferentially large-spaced, small-aperture distributed self-circulating processing casing for stabilization of an aero-compressor with splitter blades according to claim 6, characterized in that, The suction groove structure (2), the first jet orifice (31), and the second jet orifice (41) are all elliptical, rectangular, or superelliptical in shape. When the shape of the orifice is elliptical, the ratio of its major semi-axis b to its minor semi-axis a is 1.0 to 5.0, and its area is πab. When the shape of the orifice is rectangular, the ratio of its long side c to its short side d is 1.0 to 5.0, and it can also have a small radius rounded corner with a radius r. The ratio of the rounded corner radius r to the short side d is 0.1 to 0.25, and its area is cd-4r. 2 +πr 2 When the shape of the hole is a hyperellipse, (x / a) n +(y / b) n =1, the ratio of its major semi-axis b to its minor semi-axis a is 1.0 to 5.0, its exponent n is 2.0 to 10.0, and its area is 4ab*(Γ(1+1 / n)). 2 / Γ(1+2 / n), Γ(z) is t z-1 / e t Integrating t from 0 to positive infinity, when z is an integer, Γ(z) = (z-1)!.

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