A flow control method and structure coupling blade slotting with a self-circulation processing casing

Abstract

A flow control method and structure coupling blade slotting and a self-circulation processing casing according to the present invention belong to the technical field of internal flow control of turbomachinery; jet slots are opened on the stator blades; a deflector is arranged in the jet slots to divide the jet flowing into the inlet of the jet slots; a self-circulation structure is arranged between the jet slots and the rotor blade tip; under the action of the pressure difference between the suction surface and the pressure surface of the stator blade, the self-adaptive jet flows into from the inlet on the pressure surface side of the jet slots, flows through the deflector, and a part of the self-adaptive jet flows towards the top of the jet slots under the action of the deflector, enters the self-circulation structure, and finally flows into the mainstream channel at the rotor blade tip; another part of the self-adaptive jet flows out from the outlet on the suction surface side under the action of the deflector. The present invention solves the technical problem that the traditional self-circulation casing expands the stable operating range of the compressor, but causes losses to the efficiency at the design point.

Description

Technical Field

[0001] The present invention belongs to the technical field of internal flow control of turbomachinery, and particularly relates to a flow control method and structure coupling blade slotting and a self-circulating treatment casing. Background Art

[0002] Modern high-performance aero-engines are developing towards the direction of high thrust-to-weight ratio, low fuel consumption rate and high reliability. Researchers expect to use technical means to obtain a higher total pressure ratio of the compressor with fewer compressor stages, which puts higher requirements on the overall performance and stability of a single-stage compressor. As an effective stability augmentation measure, the self-circulating treatment casing can improve the stability of the compressor while taking into account the efficiency of the compressor at the design condition, so it has been widely used in engineering. On the other hand, due to the increase in the single-stage load of the compressor, there is a strong adverse pressure gradient in the compressor blade passage, and the air flow is prone to boundary layer separation at the suction surface of the blade, resulting in an increase in flow loss. Blade slotting, as a passive control measure, can form an adaptive jet using the pressure difference between the pressure surface and the suction surface of the blade, and expand the effective flow area in the blade passage and reduce the flow loss by increasing the kinetic energy of the fluid in the low-speed area. However, due to the existence of an adverse pressure gradient in the axial direction of the axial compressor, only blade slotting cannot achieve the purpose of expanding the stability of the compressor.

[0003] Therefore, based on the above technical problems, the present invention couples blade slotting with a self-circulating treatment casing, and designs a new flow control method coupling blade slotting and a self-circulating treatment casing, so as to achieve the design goal of both reducing the flow loss in the blade passage and improving the stability of the compressor. Summary of the Invention

[0004] Technical Problems to be Solved

[0005] In order to avoid the deficiencies of the prior art, reduce the flow loss in the stator blade passage, and expand the stable operating range of the compressor, the present invention provides a flow control method and structure coupling blade slotting and a self-circulating treatment casing, which separates the air extraction section of the self-circulating treatment casing into three air extraction sources, and arranges the three air extraction ports at the top of the stator blade (at the casing). Three jet slots are opened on the stator blade and air flow baffles with adjustable radial positions are arranged in the jet slots, and the air extraction ports of the self-circulating structure are connected to the tops of the jet slots (at the casing). Compared with the traditional self-circulating casing, the new flow control method coupling blade slotting and a self-circulating treatment casing not only expands the stable operating range of the compressor, but also can reduce the flow loss caused by boundary layer separation in the stator blade passage. It solves the technical problem that the traditional self-circulating casing expands the stable operating range of the compressor but causes a loss in the efficiency at the design point.

[0006] The technical solution of the present invention is as follows: A flow control method coupling blade slotting and a self-circulation processing casing, and the specific steps are as follows:

[0007] Jet slots are opened on the stator blades;

[0008] A deflector is arranged in the jet slot to split the jet flowing into the inlet of the jet slot;

[0009] A self-circulation structure is arranged between the jet slot and the rotor tip;

[0010] Under the pressure difference between the suction surface and the pressure surface of the stator blade, the self-adaptive jet flows in from the inlet on the pressure surface side of the jet slot, flows through the deflector, and a part of the self-adaptive jet flows to the top of the jet slot under the action of the deflector, enters the self-circulation structure, and finally flows into the mainstream channel at the rotor tip; another part of the self-adaptive jet flows out from the outlet on the suction surface side under the action of the deflector.

[0011] A further technical solution of the present invention is that the method for the deflector to split the jet is that the deflector is inclined in the jet slot, the position height of its near-suction surface end is set to be greater than the position height of the near-pressure surface end, and the control of the flow rates of the two parts is completed by adjusting the inclination; when the inclination direction of the deflector is closer to the radial direction, the airflow flowing into the self-circulation structure increases, and the airflow flowing out from the suction surface decreases; when the inclination direction of the deflector is closer to the axial direction, the airflow flowing into the self-circulation structure decreases, and the airflow flowing out from the suction surface increases.

[0012] A flow control structure coupling blade slotting and a self-circulation processing casing includes a jet slot opened on the stator blade for connecting the pressure surface and the suction surface, a deflector arranged in the jet slot for controlling the flow rate, and a self-circulation structure for connecting between the jet slot and the rotor tip;

[0013] The jet is introduced at the inlet on the pressure surface side of the jet slot, the jet flows through the deflector, and a part of the jet flows to the top of the jet slot under the action of the deflector, enters the self-circulation structure, and finally flows into the mainstream channel at the rotor tip; another part of the jet flows out from the outlet on the suction surface side under the action of the deflector.

[0014] A further technical solution of the present invention is that three jet slots are arranged on the stator blade, and their radial positions are in the range of 25% to 100% of the blade height; the inlet of the jet slot is located on the pressure surface side, and the width is 8% Ca; the outlet of the jet slot is located on the suction surface side, and the width is 5% Ca.

[0015] A further technical solution of the present invention is that the near-suction surface end of the deflector is installed at the rotor tip, and the radial height of the near-pressure surface end can be adjusted according to the flow rate requirement.

[0016] A further technical solution of the present invention is that for the end of the deflector with adjustable height, the lower its radial height, the more air flow flows into the self-circulation structure and the less air flow flows out from the suction surface; the higher its radial position, the less air flow flows into the self-circulation structure and the more air flow flows out from the suction surface.

[0017] A further technical solution of the present invention is that the self-circulation structure includes an air intake section, a bridge path, and a jet section arranged in sequence. The air intake port of the air intake section is located in the radial extension direction of the jet slot and is connected to the top opening of the jet slot to introduce the jet flow diverted by the deflector in the jet slot into the self-circulation structure; the bridge path extends along the casing wall towards the rotor direction, and the jet flow is introduced into the bridge path through a transition section at the air intake end. The inlet cross-section of the transition section rotates 60° towards the mainstream direction to obtain an outlet cross-section connected to the bridge path; the inlet of the jet section is connected to the outlet of the bridge path, and the jet port faces the leading edge of the rotor blade tip.

[0018] A further technical solution of the present invention is that the inner channel in the bridge path is separated by an internal baffle into bridge path channels corresponding one by one to the number of jet slots and air intake sections.

[0019] Alternatively, the inner channel in the bridge path is an integral channel to converge the jet flows of multiple air intake sections. When using an integral channel, it is necessary to ensure that the static pressures of the air flows at the outlets of the three air intake sections are approximately equal. Otherwise, due to the differences in the static pressure values of the three independent air intake sources, the air intake source with a lower static pressure will have a reverse flow or no flow phenomenon.

[0020] A further technical solution of the present invention is that the jet section adopts a Coanda curve design, with a throat height of 0.16 mm, the included angle between the jet direction of the circulating air flow and the mainstream is 10°, the axial distance of the jet port is 3 mm, the circumferential coverage rate is 12.5%, and the axial position of the trailing edge of the jet port is the same as the axial position of the leading edge of the rotor blade tip.

[0021] A compressor includes a flow control structure in which a novel blade slotting is coupled with a self-circulation processing casing, and the number of the flow control structures is the same as the number of stator blades, and they are arranged in one-to-one correspondence.

[0022] Beneficial effects

[0023] The beneficial effects of the present invention are as follows: By applying the flow control method coupling the new blade slotting and the self-circulation treatment casing on a single-stage subsonic axial compressor, the comprehensive stall margin of the compressor is increased by 3.7%, and the absolute value of the isentropic efficiency of the compressor under the near-stall condition of the solid wall casing is increased by 1.1%. That is, compared with the traditional self-circulation casing, the flow control method coupling the new blade slotting and the self-circulation treatment casing not only improves the comprehensive stall margin of the compressor, but also obtains a considerable efficiency increment under the stall condition. The flow control method coupling the new blade slotting and the self-circulation treatment casing overcomes the problem that the traditional self-circulation treatment casing causes a certain loss to the isentropic efficiency of the compressor during stability augmentation.

[0024] When the single-stage subsonic axial compressor is in the small flow rate condition, due to the excessive air flow attack angle, the boundary layer on the suction surface of the compressor stator blade will separate, generating a large amount of low-speed fluid and causing losses. Moreover, due to the expansion and fragmentation of the tip leakage flow of the rotor, a large area of low-speed region will also be generated in the rotor tip passage, inducing the instability of the compressor when the flow rate of the compressor further decreases. The air intake of the self-circulation structure introduces the air flow on the pressure surface of the stator blade into the self-circulation casing under the action of the air flow baffle in the jet slot. The circulating air flow with a high jet speed effectively blows away the low-speed fluid in the rotor tip passage, ultimately achieving the effect of improving the stability of the compressor. Another part of the jet directly sprays out on the suction surface of the blade, increasing the gas kinetic energy in the low-speed area on the suction surface, reducing the flow loss in the blade passage, and enhancing the efficiency of the compressor. Description of the Drawings

[0025] Figure 1 It is the overall three-dimensional view of the flow control method coupling the new blade slotting and the self-circulation treatment casing.

[0026] Figure 2 It is the three-dimensional geometric structure schematic diagram of the self-circulation treatment casing in the flow control method coupling the new blade slotting and the self-circulation treatment casing.

[0027] Figure 3 It is the partial enlarged view of the airflow direction turning part of the self-circulation treatment casing in the flow control method coupling the new blade slotting and the self-circulation treatment casing.

[0028] Figure 4 It is the schematic diagram of the relative axial position between the jet port of the self-circulation treatment casing and the leading edge of the rotor tip in the flow control method coupling the new blade slotting and the self-circulation treatment casing.

[0029] Figure 5 It is the schematic diagram of the three-stage design method of the stator jet slot in the flow control method coupling the new blade slotting and the self-circulation treatment casing.

[0030] Figure 6 ​In the flow control method coupling a new type of vane slotted with a self - circulating treatment casing, it is a schematic diagram of the stator jet slot and the baffle structure inside the jet slot (in order to make the picture clear and tidy, only one stator suction slot and the baffle structure are shown).

[0031] Figure 7 It is a schematic diagram of the air flow direction of the flow control method coupling a new type of vane slotted with a self - circulating treatment casing, where the solid - line arrow represents the mainstream direction, the dashed - line arrow represents the jet direction, and the dotted - line arrow represents the circulating air flow direction.

[0032] Explanation of reference numerals: 1. Rotor; 2. Stator vane; 3. Stator jet slot; 4. Air - extraction section (air - extraction port) of the self - circulating structure; 5. Bridge path of the self - circulating structure; 6. Jet section (jet port) of the self - circulating structure; 7. Adjustable deflector inside the jet slot. Detailed implementation manners

[0033] The embodiments described below by referring to the attached drawings are exemplary and intended to explain the present invention, and should not be construed as a limitation to the present invention.

[0034] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention.

[0035] Define the names of each direction as follows: Axial direction - along the axis direction of the cylinder; Radial direction - along the cross - section radius direction (perpendicular to the axis); Circumferential direction - around the axis direction of the cylinder (perpendicular to the axis and perpendicular to the cross - section radius), the blade tip - the side of the blade close to the casing is the blade tip, and the blade root - the side of the blade close to the hub is the blade root.

[0036] When a single - stage subsonic axial - flow compressor is in a small - flow condition, due to the excessive air - flow attack angle, the boundary layer on the suction surface of the compressor stator vane will separate, generating a large amount of low - speed fluid and causing losses. Moreover, due to the expansion and fragmentation of the tip leakage flow of the rotor, a large - area low - speed region will also be generated in the rotor tip passage, inducing the instability of the compressor when the compressor flow rate further decreases. The present invention provides a flow control method and system coupling a new type of vane slotted with a self - circulating treatment casing. The method is as follows:

[0037] Open jet slots on the stator vanes;

[0038] A flow deflector is arranged in the jet slot to split the jet flowing into the jet slot inlet;

[0039] A self - circulation structure is arranged between the jet slot and the rotor tip;

[0040] Under the action of the pressure difference between the suction surface and the pressure surface of the stator blade, the self - adaptive jet flows into from the inlet on the pressure surface side of the jet slot, flows through the flow deflector. Part of the self - adaptive jet flows towards the top of the jet slot under the action of the flow deflector, enters the self - circulation structure, and finally flows into the mainstream channel at the rotor tip; the other part of the self - adaptive jet flows out from the outlet on the suction surface side under the action of the flow deflector.

[0041] Specifically, the method for the flow deflector to split the jet is that the flow deflector is inclined in the jet slot, and the position height of its end near the suction surface is set to be greater than the position height of the end near the pressure surface. The control of the flow rates of the two parts is completed by adjusting the inclination. When the inclination direction of the flow deflector is closer to the radial direction, the airflow flowing into the self - circulation structure increases, and the airflow flowing out from the suction surface decreases; when the inclination direction of the flow deflector is closer to the axial direction, the airflow flowing into the self - circulation structure decreases, and the airflow flowing out from the suction surface increases.

[0042] Compared with the single self - circulation treatment casing and the single blade slotted flow control strategy, the new flow control method of coupling blade slotted and self - circulation treatment casing can firstly use the circulating airflow to improve the stability of the compressor; secondly, it can use the self - adaptive jet to blow away the low - speed fluid generated by the boundary layer separation and reduce the flow loss in the stator blade passage; in addition, the flow rate of the self - circulation airflow and the self - adaptive jet can also be adjusted by adjusting the radial height of the baffle near the pressure surface end.

[0043] Refer to Figure 1 As shown, the new flow control structure of coupling blade slotted and self - circulation treatment casing includes a jet slot opened on the stator blade for connecting the pressure surface and the suction surface, a flow deflector arranged in the jet slot for controlling the flow rate, and a self - circulation structure for connecting between the jet slot and the rotor tip; the inlet on the pressure surface side of the jet slot introduces the jet, the jet flows through the flow deflector, part of the jet flows towards the top of the jet slot under the action of the flow deflector, enters the self - circulation structure, and finally flows into the mainstream channel at the rotor tip; the other part of the jet flows out from the outlet on the suction surface side under the action of the flow deflector.

[0044] Specifically, refer to Figure 5 As shown, three jet slots are arranged on the stator blade, and their radial range is 25% - 100% of the blade height. The widths of the inlet and outlet of the jet slot are 8%Ca and 5%Ca respectively. The jet slot adopts a three - section design of an inlet section, a transition section and an outlet section. For blades with a smaller thickness, a two - section design of an inlet section and an outlet section can be adopted.

[0045] Specifically, refer toFigure 6 As shown, a baffle is arranged in the jet slot. The radial height of one end of the baffle near the suction surface is fixed at the blade tip, and the radial height of the other end near the pressure surface can be adjusted. Refer to Figure 7 As shown, due to the pressure difference between the suction and pressure surfaces of the blade, an adaptive jet that flows in from the pressure surface and out from the suction surface will be generated in the jet slot. Under the action of the baffle, a part of the adaptive jet flows along the baffle towards the top of the jet slot (flowing towards the casing), and is finally sucked into the self-circulation structure by the self-circulation air intake; another part of the adaptive jet flows out from the suction surface of the blade.

[0046] Specifically, for the end of the baffle near the pressure surface with adjustable radial height, the lower its radial height, the more air flows into the self-circulation structure and the less air flows out from the suction surface; the higher its radial position, the less air flows into the self-circulation structure and the more air flows out from the suction surface.

[0047] Specifically, refer to Figure 2 As shown, the self-circulation processing casing part is composed of three parts: an air intake section, a bridge path, and a jet section, using the traditional self-circulation casing design method. However, the air intake section has three air intake ports, corresponding to three independent air intake sources respectively. The air intake section inlet is connected to the top of the jet slot (near the casing).

[0048] Specifically, refer to Figure 7 As shown, the air flow direction in the compressor can be summarized as follows: due to the differential pressure between the suction and pressure surfaces of the stator blades, an adaptive jet is formed. A part of the adaptive jet flows out from the suction surface, and another part of the air flows upward into the self-circulation structure under the action of the baffle. After passing through the air intake section, bridge path, and jet section of the self-circulation structure, it finally flows into the mainstream channel at the blade tip of the rotor.

[0049] Specifically, refer to Figure 3 As shown, for the design of the transition part of the air intake section of the self-circulation structure, it is generated by rotating the cross-section of the transition part inlet by 60° in the direction of the mainstream incoming flow (the reverse direction of the Z-axis).

[0050] Specifically, the bridge path of the self-circulation processing casing can be divided into three independent bridge path channels with a smaller flow area by using two built-in baffles, or the baffles can be removed to design it as a bridge path channel with a larger flow area. When the baffles are removed and the bridge path is designed as a channel with a larger flow area, it is necessary to ensure that the static pressures of the air flows at the outlets of the three air intake sections are approximately equal. Otherwise, due to the differences in the static pressure values of the three independent air intake sources, the air intake source with a lower static pressure will have a reverse flow or non-flow phenomenon.

[0051] Specifically, the method to ensure that the static pressures of the airflows at the outlets of the three air extraction sections are approximately equal is to adjust the outlet areas of the air extraction sections to control the static pressures of the airflows at the outlets of the three air extraction sections to be approximately equal. The specific calculation process is as follows: There are the Bernoulli equation (Formula 1) and the mass conservation equation (Formula 2).

[0052]

[0053] ρ in A in v in =ρ out A out v out (2)

[0054] In the formula, the subscript "in" represents the connection section between the air extraction section of the self-circulation structure and the jet groove, and the subscript "out" represents the connection section between the air extraction section of the self-circulation structure and the bridge channel. It is considered that ρ in =ρ out . The total pressure of the airflow in a certain air extraction section of the self-circulation structure can be measured. After determining the static pressure value of the airflow at the outlet of the air extraction section, the airflow velocity v out at the connection section between the air extraction section and the bridge channel can be calculated by Formula (2). Then, according to Formula (1), the area A out of the connection section between the air extraction section and the bridge channel can be calculated, and finally, the static pressures of the airflows at the outlets of the three air extraction sections are ensured to be approximately equal.

[0055] Specifically, as shown in Figure 1 , the jet section is designed with a Coanda curve, the throat height is 0.16 mm, the included angle between the jet direction of the circulating airflow and the mainstream is 10°, the axial distance of the jet port is 3 mm, the circumferential coverage rate is 12.5%, and the axial position of the trailing edge of the jet port is the same as the axial position of the leading edge of the rotor blade tip.

[0056] In this embodiment, a compressor arranges 20 self-circulation structures within the full circumferential range, and the number thereof is the same as the number of stator blades.

[0057] The above technical solutions are further described through specific experiments below.

[0058] See Figures 1 to 6, A flow control method coupling a novel vane slotting and self - circulation processing casing in this embodiment. In the flow control method coupling the novel vane slotting and self - circulation processing casing, the air extraction position of the self - circulation structure is arranged above the stator vane passage. Three jet slots are opened on the stator vane, and radial baffles are arranged in the jet slots. The air extraction port of the self - circulation processing casing is connected to the top end of the stator vane jet slot, and the axial position of the trailing edge of the jet outlet is the same as the axial position of the leading edge of the rotor tip. Additionally, 20 self - circulation structures are arranged circumferentially, and this number is the same as the number of vanes. The advantages of the flow control method coupling the novel vane slotting and self - circulation processing casing are as follows: On the one hand, due to the pressure difference between the suction and pressure surfaces of the stator vane, the jet increases the kinetic energy of the low - speed fluid on the suction surface of the stator vane, expands the effective flow area, and effectively reduces the flow loss in the stator vane passage, thus improving the compressor efficiency; on the other hand, the self - circulation structure can use the baffles in the jet slots to suck in part of the air flow from the stator vane passage and eject it in the rotor tip passage to increase the kinetic energy of the low - speed fluid in the rotor tip passage and achieve the purpose of improving the compressor stability.

[0059] A flow control method coupling a novel vane slotting and self - circulation processing casing based on a single - stage subsonic axial - flow compressor, which is characterized by including the following steps:

[0060] Step 1: Open three jet slots on the compressor stator vane. The axial positions of the jet slot outlets are successively: 15% Ca, 50% Ca, and 85% Ca (Ca represents the axial chord length of the stator tip), the width of each slot is 8% Ca (which can be selected within the range of 8% Ca - 13% Ca), and the radial range of the jet slot is 25% - 100% blade height (the radial range can be selected and designed according to the boundary - layer separation degree of different blade - height sections).

[0061] Step 2: Arrange air flow baffles in the jet slots so that part of the jet is sucked into the self - circulation structure by the air extraction port under the action of the baffles. The larger the radial range of the baffle, the larger the flow rate of the circulating air flow and the lower the jet flow rate; the smaller the radial range of the baffle, the smaller the flow rate of the circulating air flow and the higher the jet flow rate.

[0062] Step 3: The axial position of the leading edge of the jet outlet of the self - circulation structure is the same as the axial position of the leading edge of the rotor tip. The profile of the jet section of the self - circulation structure is designed with a Coanda curve, the throat height is 0.16 mm, the jet angle is 10°, and the distance between the suction surface and the pressure surface of the jet outlet is 3 mm.

[0063] Step 4: Design the air extraction section of the self - circulation structure according to the maximum height of the jet section of the self - circulation structure. To ensure that the static pressures of the three air extraction sections at the connection section with the bridge are the same, calculate the corresponding outlet cross - sectional area of the air extraction section according to the Bernoulli equation (Formula 1) and the mass - conservation equation (Formula 2). The transition part of the air flow direction in the air extraction section is designed with an arc, and the rotation angle is 60°.

[0064] Step 5: Horizontally extend the inlet profile of the self - circulating structure jet section towards the stator blade direction to form a bridge path with a length of 50 mm.

[0065] Step 6: Connect the direction transition part of the air extraction section to the inlet section of the bridge path with a straight line to finally form a complete air flow path.

[0066] Step 7: Arrange 20 self - circulating structures generated as described in Steps 1 - 6 circumferentially, which is consistent with the number of stator blades.

[0067] The present invention is applied to the single - stage subsonic axial - flow compressor of Northwestern Polytechnical University, and the main parameters of this compressor are shown in Table 1.

[0068] Table 1 Design Parameters of the Single - Stage Subsonic Axial - Flow Compressor of Northwestern Polytechnical University

[0069]

[0070] Taking the single - stage subsonic axial - flow compressor of Northwestern Polytechnical University as the research object, a non - steady numerical simulation study on the flow control method coupling new blade slotting and self - circulating treatment casing is carried out. The implementation process is as follows:

[0071] 1. Use the Autogrid5 module of the NUMECA software package to perform structured grid division on the compressor blade passage grid.

[0072] 2. Use the IGG module of the NUMECA software package to perform grid division on the stator jet slots and the self - circulating structure.

[0073] 3. Use the Fine - Turbo module of the NUMECA software package for numerical calculation. Use the Euranas solver to perform full - three - dimensional calculation on the generated numerical calculation grid. The specific configuration is as follows: the rotational speed of the compressor rotor is 10765 r / min (70% of the design speed), the spatial discretization format of the governing equation adopts the Symmetric TVD scheme of the second - order upwind format, the oscillation - limiting type of the numerical solutions in the linear domain and the non - linear domain selects the Min Mod format, the temporal discretization of the governing equation adopts the fourth - order Runge - Kutta method, the unsteady calculation adopts the dual - time - step advancement method, set the number of physical time steps for the rotor to rotate through one blade row channel to be 20, and set 20 virtual time steps under each physical time step. And adopt the multi - grid method, local time step and implicit residual smoothing and other methods to accelerate the convergence speed.

[0074] 4. Use the CFView module of the NUMECA software package to obtain the numerical calculation results and perform data processing. Based on the compressor prototype, obtain the improvement amounts of the comprehensive stall margin and efficiency of the stator blade suction - type self - circulating treatment casing.

[0075] The research results show that the comprehensive stall margin improvement of the flow control method coupling the new blade slotting and the self-circulating casing is 3.7%, and the absolute value of the isentropic efficiency of the compressor is increased by 1.1% under the near-stall condition. That is, the flow control method coupling the new blade slotting and the self-circulating casing can not only improve the stable operating margin of the compressor, but also greatly improve the isentropic efficiency of the compressor under the near-stall condition.

[0076] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention without departing from the principles and purposes of the present invention.

Claims

1. A flow control method for coupling blade slotting with a self-circulating processing casing, characterized in that The specific steps are as follows: A jet groove is provided on the stationary blade; A guide plate is provided in the jet trough to divert the jet entering the jet trough inlet; A self-circulation structure is provided between the jet slot and the rotor blade tip; Under the action of the pressure difference between the suction and pressure surfaces of the stationary blades, the adaptive jet flows in from the inlet on the pressure side of the jet slot, flows through the guide plate, and a part of the adaptive jet flows to the top of the jet slot under the action of the guide plate, enters the self-circulation structure, and finally flows into the mainstream channel at the rotor blade tip; Another part of the adaptive jet flows out from the outlet on the suction side under the action of the guide plate; The method for the guide plate to divert the jet is that the guide plate is tilted in the jet groove, and the position height of the end near the suction surface is set to be greater than the position height of the end near the pressure surface, and the control of the diversion volume of the two parts is completed by adjusting the inclination; when the tilt direction of the guide plate is closer to the radial direction, the airflow flowing into the self-circulation structure increases, and the airflow flowing out of the suction surface decreases; when the tilt direction of the guide plate is closer to the axial direction, the airflow flowing into the self-circulation structure decreases, and the airflow flowing out of the suction surface increases.

2. A flow control structure coupling blade slots with a self-circulating processing casing, characterized by: A flow control method for implementing the coupling of blade slotting and a self-circulating processing casing as described in claim 1, comprising a jet slot provided on a stationary blade for connecting the pressure side and the suction side, a guide plate provided in the jet slot for controlling the flow rate, and a self-circulating structure for connecting the jet slot and the rotor blade tip; A jet is introduced into the inlet on the pressure side of the jet groove, and the jet flows through the guide plate. A part of the jet flows to the top of the jet groove under the action of the guide plate, enters the self-circulation structure, and finally flows into the mainstream channel at the top of the rotor blade; the other part of the jet flows out from the outlet on the suction side under the action of the guide plate.

3. The flow control structure of blade slots coupled with a self-circulating processing casing according to claim 2, characterized in that: Three jet grooves are arranged on the stationary blade, and their radial positions are in the range of 25% to 100% of the blade height; the jet groove inlet is located on the pressure surface side, and the width is 8%Ca; the jet groove outlet is located on the suction surface side, and the width is 5%Ca.

4. The flow control structure of blade slots coupled with a self-circulating processing casing according to claim 2, characterized in that: The guide plate is installed at the blade tip at one end near the suction surface, and the radial height of the guide plate at one end near the pressure surface can be adjusted according to flow requirements.

5. The flow control structure of blade slots coupled with a self-circulating processing casing according to claim 4, characterized in that: The guide plate has an adjustable height at one end. The lower its radial height is, the more air flows into the self-circulation structure and the less air flows out from the suction surface; the higher its radial position is, the less air flows into the self-circulation structure and the more air flows out from the suction surface.

6. The flow control structure of blade slots coupled with a self-circulating processing casing according to claim 2, characterized in that: The self-circulation structure includes an air bleed section, a bridge and an injection section arranged in sequence. The air bleed port of the air bleed section is located in the radial extension direction of the jet groove and is connected to the top opening of the jet groove, so that the jet diverted by the guide plate in the jet groove is introduced into the self-circulation structure; the bridge extends along the wall of the casing toward the rotor, and the air bleed end introduces the jet into the bridge through the transition section. The inlet section of the transition section is rotated 60° toward the direction of the mainstream flow to obtain an outlet section connected to the bridge; the inlet of the injection section is connected to the outlet of the bridge, and the nozzle faces the leading edge of the rotor blade.

7. The flow control structure of blade slots coupled with a self-circulating processing casing according to claim 6, characterized in that: The inner channel of the bridge is divided by built-in baffles into bridge channels corresponding to the number of jet slots and air entrainment sections; Alternatively, the channel within the bridge is an integral channel that merges the jets of multiple air bleed sections. When using an integral channel, it is necessary to ensure that the static pressures of the air flows at the outlets of the three air bleed sections are approximately equal. Otherwise, due to the differences in the static pressure values of the three independent air bleed sources, the air bleed source with lower static pressure will experience backflow or stagnation.

8. The flow control structure of blade slots coupled with a self-circulating processing casing according to claim 6, characterized in that: The jet section adopts a Coanda curve design, with a throat height of 0.16 mm, an angle of 10° between the circulating airflow jet direction and the mainstream, an axial distance of the jet port of 3 mm, a circumferential coverage rate of 12.5%, and the axial position of the trailing edge of the jet port is the same as the axial position of the leading edge of the rotor blade tip.

9. A compressor, characterized in that: A flow control structure comprising blade slots coupled with a self-circulating processing casing as described in any one of claims 2 to 8, the number of which is consistent with the number of stationary blades and is arranged in a one-to-one correspondence.

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