An adjustable centrifugal compressor wheel shroud structure
By designing an adjustable centrifugal compressor impeller casing structure and adjusting the blade tip clearance to adapt to different operating conditions, the problem of balancing aerodynamic noise and performance was solved, achieving performance improvement and noise reduction under different operating conditions.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-03
- Publication Date
- 2026-03-27
AI Technical Summary
Existing centrifugal compressors struggle to balance aerodynamic noise and performance under different operating conditions. Increased tip clearance leads to flow losses and noise issues, and their adaptability to operating conditions is limited.
Design an adjustable centrifugal compressor impeller casing structure, including an impeller body, an impeller casing, and an intake bypass recirculation structure. Through a radial adjustment mechanism and a labyrinth seal structure, the blade tip clearance can be adjusted to adapt to different operating conditions, reduce aerodynamic noise, and improve performance.
By adjusting the blade tip clearance under different operating conditions, aerodynamic noise can be reduced, flow losses can be decreased, compressor performance and safety margin can be improved, and the stable operating range can be widened.
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Figure CN120027086B_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of centrifugal compressor, in particular to an adjustable centrifugal compressor impeller cover structure. BACKGROUND
[0002] Turbocharging technology is widely used in the field of marine low-speed engine due to its energy saving, noise reduction and economic improvement. With the development of turbocharged centrifugal compressor towards high pressure ratio and large flow, aerodynamic noise has become a key factor restricting its development.
[0003] The maximum sound power of centrifugal compressor aerodynamic noise mainly occurs in the impeller part. For semi-open centrifugal compressor, the composition of aerodynamic noise at impeller part is different under different working conditions. In low speed working condition, the main component of aerodynamic noise is the dipole noise caused by dynamic and static interference between impeller and inlet pipe and between impeller and diffuser. In high speed working condition, in addition to the dynamic and static interference noise, the dipole noise caused by blade leading edge shock wave is also added.
[0004] In the existing research, the increase of blade tip clearance can weaken the blade leading edge shock wave, thereby reducing the noise, but there are certain defects. First, it will reduce the performance of the compressor. The increase of tip clearance will lead to the increase of tip clearance leakage flow, which will aggravate the internal flow loss of the impeller, thereby reducing the performance of the compressor. Second, the application working condition is limited. The increase of tip clearance can only simply reduce the aerodynamic noise under high speed working condition, but for low speed working condition, it will not only increase the internal flow loss of the impeller and reduce the performance of the compressor, but also increase the vortex noise of the compressor due to the increase of tip clearance leakage flow.
[0005] Based on the above situation, an adjustable centrifugal compressor impeller cover structure is proposed to solve the problems existing in the prior art. SUMMARY
[0006] The purpose of the present application is to provide an adjustable centrifugal compressor impeller cover structure to solve the problems existing in the prior art, which can meet the needs of aerodynamic performance and improve the aerodynamic noise.
[0007] To achieve the above purpose, the present application provides the following scheme:
[0008] The present application provides an adjustable centrifugal compressor impeller cover structure, which comprises an impeller body, an impeller cover and an intake bypass recirculation structure.
[0009] The impeller cover wraps the impeller body in the middle.
[0010] The shroud casing comprises a front edge shroud casing and a tail edge shroud casing arranged in sequence along the axial direction, and an air inlet gap is arranged between the front edge shroud casing and the tail edge shroud casing; and the gap between the impeller body and the front edge shroud casing and the tail edge shroud casing forms a centrifugal compressor tip clearance.
[0011] The front edge shroud casing comprises a plurality of front edge shroud casing units distributed along the circumference; each of the front edge shroud casing units is connected in sequence along the circumference; and each adjacent two of the front edge shroud casing units are connected through a labyrinth seal structure.
[0012] The air inlet bypass recirculation structure comprises a recirculation structure outer wall, the recirculation structure outer wall is arranged around the outside of the shroud casing, the tail edge of the recirculation structure outer wall is fixedly connected with the tail edge shroud casing, and the recirculation structure outer wall and the shroud casing form a recirculation structure cavity therebetween; and the air inlet gap is communicated with the centrifugal compressor tip clearance and the recirculation structure cavity.
[0013] Each of the front edge shroud casing units is fixedly provided with a front edge shroud casing fixing structure on the outer side wall; the recirculation structure outer wall is fixedly provided with a fixing structure cavity corresponding to each of the front edge shroud casing fixing structures; the front edge shroud casing fixing structure and the fixing structure cavity are nestedly connected; and each of the front edge shroud casing fixing structures is provided with a radial adjusting mechanism for adjusting the radial position of the front edge shroud casing fixing structure.
[0014] In an embodiment, the front edge shroud casing comprises six front edge shroud casing units distributed along the circumference.
[0015] In an embodiment, the radial adjusting mechanism comprises a lead screw and a lead screw knob; the lead screw is rotationally connected to the recirculation structure outer wall and fixedly arranged in radial opposition to the recirculation structure outer wall; the front edge shroud casing fixing structure is provided with a threaded hole threadedly connected with the lead screw; and the lead screw knob is connected to the radially outward end of the lead screw for rotating the lead screw.
[0016] In an embodiment, the inner side of the fixing structure cavity is fixedly provided with a limiting convex ring, and the front edge shroud casing fixing structure is provided with an annular limiting groove corresponding to the limiting convex ring; and the limiting convex ring is gap-fittingly arranged in the annular limiting groove.
[0017] In an embodiment, the front edge shroud casing fixing structure comprises an axially inclined elliptical type structure or a streamline type structure; and the fixing structure cavity is a structure cavity matched with the shape of the front edge shroud casing fixing structure.
[0018] In an embodiment, the lead screw is rotatably connected to the outer wall of the recirculation structure through a bearing.
[0019] In an embodiment, the lead screw knob is sleeved on the lead screw and connected to the lead screw through a flat key.
[0020] In an embodiment, the outer wall of the recirculation structure, the tail edge impeller cover shell and the fixed structure cavity are integrated.
[0021] In an embodiment, the front edge impeller cover shell unit and the front edge impeller cover shell fixing structure thereon are integrated.
[0022] The present application has the following technical effects relative to the prior art:
[0023] The adjustable centrifugal compressor impeller cover shell structure provided by the present application can change the front edge blade tip clearance as needed, can reduce the centrifugal compressor aerodynamic noise on the basis of meeting the aerodynamic performance needs, can increase the front edge blade tip clearance in high speed working conditions to weaken the front edge shock wave and reduce the aerodynamic noise, can reduce the front edge blade tip clearance in low speed working conditions to reduce the flow loss inside the impeller and improve the compressor performance, and can also reduce the vortex noise of the compressor due to the reduction of blade tip clearance leakage flow.
[0024] The adjustable centrifugal compressor impeller cover shell structure provided by the present application can not only be used in high and low speed working conditions, but also can be adjusted according to the deformation of the blade caused by the influence of thermal load, centrifugal force and aerodynamic load during the operation of the compressor, so as to change the blade tip clearance and improve the performance and safety margin of the compressor.
[0025] The present application starts from changing the blade tip clearance structure itself, adopts a mechanical transmission structure, is relatively safe and reliable, and is provided with a radial limiting structure (limiting convex ring and annular limiting groove) to ensure the safe operation of the compressor and avoid blade wear and other problems. BRIEF DESCRIPTION OF DRAWINGS
[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.
[0027] Figure 1 The structural schematic diagram of the adjustable centrifugal compressor impeller cover shell structure in the embodiments of the present application is shown in the figure.
[0028] Figure 2 The structural schematic diagram of the adjustable centrifugal compressor impeller cover shell structure in the embodiments of the present application is shown in the figure. Figure 1A partial enlarged view of the middle part A;
[0029] Figure 3 For Figure 1 A partial enlarged view of the middle part B;
[0030] Figure 4 A side view of the front edge impeller cover shell in the embodiment of the present application;
[0031] Figure 5 A sectional view of the recirculation structure outer wall and the trailing edge impeller cover shell in the embodiment of the present application;
[0032] Figure 6 A sectional view of the radial adjustment mechanism in the embodiment of the present application.
[0033] In the figure: 1-impeller body, 2-impeller cover shell, 3-inlet bypass recirculation structure, 4-front edge impeller cover shell, 5-trailing edge impeller cover shell, 6-inlet gap, 7-front edge impeller cover shell unit, 8-maze seal structure, 9-recirculation structure outer wall, 10-recirculation structure cavity, 11-front edge impeller cover shell fixing structure, 12-fixing structure cavity, 13-radial adjustment mechanism, 14-screw rod, 15-screw rod knob, 16-thread hole, 17-limiting convex ring, 18-annular limiting groove. DETAILED DESCRIPTION
[0034] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.
[0035] The purpose of the present application is to provide an adjustable centrifugal compressor impeller cover shell structure to solve the problems in the prior art, which can meet the needs of aerodynamic performance and improve aerodynamic noise.
[0036] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application will be further described in detail below with reference to the drawings and specific embodiments.
[0037] As Figures 1-6 shown, the present embodiment provides an adjustable centrifugal compressor impeller cover shell structure, which comprises an impeller body 1, an impeller cover shell 2 and an inlet bypass recirculation structure 3.
[0038] The impeller cover shell 2 wraps the impeller body 1 in the middle in the circumferential direction.
[0039] The shroud 2 comprises a leading edge shroud 4 and a trailing edge shroud 5 arranged in sequence along the axial direction, and the leading edge shroud 4 and the trailing edge shroud 5 are provided with an air inlet gap 6 therebetween, and the gap between the shroud body 1 and the leading edge shroud 4 and the trailing edge shroud 5 forms a centrifugal compressor tip clearance;
[0040] The leading edge shroud 4 comprises a plurality of leading edge shroud units 7 arranged uniformly along the circumferential direction, each of the leading edge shroud units 7 is connected in sequence along the circumferential direction, and each adjacent two leading edge shroud units 7 are connected through a labyrinth seal structure 8; the labyrinth seal structure 8 can not only ensure the air tightness of the leading edge shroud 4, but also provide space for the radial movement of each part of the leading edge shroud 4 by using the gap allowance of the labyrinth seal structure 8;
[0041] In the embodiment, the leading edge shroud 4 comprises six leading edge shroud units 7 arranged uniformly along the circumferential direction; so that the circumferential variation of the leading edge tip clearance is as uniform as possible, and the error of the central leading edge tip clearance variation of each part of the leading edge shroud unit 7 and the leading edge tip clearance variation on the labyrinth seal side is only 13.3%;
[0042] The air inlet bypass recirculation structure 3 comprises a recirculation structure outer wall 9, the recirculation structure outer wall 9 is arranged around the outside of the shroud 2, the trailing edge of the recirculation structure outer wall 9 is fixedly connected with the trailing edge shroud 5, and the recirculation structure outer wall 9 and the shroud 2 form a recirculation structure cavity 10 therebetween, and the air inlet gap 6 connects the centrifugal compressor tip clearance and the recirculation structure cavity 10;
[0043] The gas enters the compressor impeller flow passage axially through the leading edge shroud 4, the rotating shaft drives the shroud body 1 to rotate, under the action of centrifugal force and the restriction of the trailing edge shroud 5, the blades compress the gas entering the impeller flow passage, and convert mechanical energy into kinetic energy and pressure energy of the gas, and then the gas is discharged at the trailing edge of the shroud.
[0044] The gas blocked between the shroud body 1 and the leading edge shroud 4 and the trailing edge shroud 5 flows back into the recirculation structure cavity 10 from the air inlet gap 6, and then mixes with the normal air and enters the centrifugal compressor impeller flow passage axially through the leading edge shroud 4.
[0045] Each of the leading edge shroud units 7 is fixedly provided with a leading edge shroud fixing structure 11 on the outer side wall, the recirculation structure outer wall 9 is fixedly provided with a fixing structure cavity 12 corresponding to each of the leading edge shroud fixing structures 11, the leading edge shroud fixing structure 11 and the fixing structure cavity 12 are nested and connected, the nested connection structure fixes the circumferential position of the leading edge shroud unit 7, but does not limit the radial movement of the leading edge shroud unit 7, and each of the leading edge shroud fixing structures 11 is provided with a radial adjusting mechanism 13 for adjusting the radial position of the leading edge shroud fixing structure 11.
[0046] In the embodiment, the radial adjustment mechanism 13 comprises a screw rod 14 and a screw knob 15. The screw rod 14 is rotationally connected to the outer wall 9 of the recirculation structure and fixed radially opposite to the outer wall 9 of the recirculation structure. The front edge impeller cover shell fixed structure 11 is provided with a threaded hole 16 threadedly connected to the screw rod 14. The screw knob 15 is connected to the radially outward end of the screw rod 14 and used to rotate the screw rod 14. The radial position of the front edge impeller cover shell unit 7 can be finely adjusted by rotating the screw rod 14, so as to change the blade leading edge tip clearance. Since the tip clearance is a small structure, most of which is about 0.65 mm, the range of change of the tip clearance is also small. In order to finely move the front edge impeller cover shell unit 7 radially, the thread pitch of the threaded hole 16 and the screw rod 14 can be reduced, so as to realize fine radial movement.
[0047] The inlet bypass recirculation structure 3 serves as a fixed structure and plays a role of fixing the screw rod 14 and the screw knob 15 in the radial direction, so as to realize the function of the radial adjustment mechanism 13. The gas recirculation can utilize the pressure difference principle to suck the high-pressure low-speed flow blocked in the tip area into the recirculation structure cavity 10 through the inlet gap 6, and then mix with the normal inlet gas to enter the centrifugal compressor impeller flow passage axially through the front edge impeller cover shell 4, so as to effectively relieve the surge of the centrifugal compressor, thereby expanding the stable operation range of the centrifugal compressor.
[0048] In the embodiment, the inner side of the fixed structure cavity 12 is fixedly provided with a limiting convex ring 17, and the front edge impeller cover shell fixed structure 11 is provided with an annular limiting groove 18 corresponding to the limiting convex ring 17. The limiting convex ring 17 is gap-fitted in the annular limiting groove 18. Through the cooperation of the limiting convex ring 17 and the annular limiting groove 18, the radial movement distance of the front edge impeller cover shell unit 7 can be controlled within a safety margin. The size of the gap can be determined by tests, which can prevent the blade from being worn and collided due to the too small front edge tip clearance, and can prevent the compressor efficiency from being significantly reduced due to the too large front edge tip clearance.
[0049] In order not to hinder the flow of gas in the recirculation structure cavity 10, the front edge impeller cover shell fixed structure 11 comprises an axially inclined elliptical structure or a streamline structure. The fixed structure cavity 12 is a structure cavity matched with the shape of the front edge impeller cover shell fixed structure 11. In the embodiment, the front edge impeller cover shell fixed structure 11 is an elliptical structure. The streamline structure includes an airfoil structure. The shape of the front edge impeller cover shell fixed structure 11 is not limited to the above shapes, and can be based on the function of the present application.
[0050] In the embodiment, the screw rod 14 is rotationally connected to the outer wall 9 of the recirculation structure through a bearing.
[0051] In this embodiment, the lead screw knob 15 is sleeved on the lead screw 14 and connected to the lead screw 14 via a flat key.
[0052] In this embodiment, the outer wall 9 of the recirculation structure, the tail impeller cover 5, and the fixed structure cavity 12 are an integral structure.
[0053] In this embodiment, the leading edge impeller housing unit 7 and the leading edge impeller housing fixing structure 11 thereon are an integral structure.
[0054] This invention features six lead screw knobs 15, which are simultaneously rotated under the control of a controller. When the speed sensor detects a decrease in the centrifugal compressor speed, it sends a signal to the controller, which then simultaneously controls the rotation of all six lead screw knobs 15. The controller can control the rotation of the lead screw knobs 15 via a rotary motor or rotary cylinder, causing the six leading edge impeller casing units 7 to move radially inward simultaneously, reducing the leading edge tip clearance. This reduces internal flow losses in the impeller, improves compressor performance, and also reduces compressor vortex noise due to the reduced tip clearance leakage. When the speed sensor detects an increase in the centrifugal compressor speed, it sends a signal to the controller, which then simultaneously controls the rotation of all six lead screw knobs 15, causing the six leading edge impeller casing units 7 to move radially outward simultaneously, increasing the leading edge tip clearance. This weakens the leading edge shock wave and reduces aerodynamic noise.
[0055] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.
Claims
1. An adjustable centrifugal compressor impeller casing structure, characterized in that: Includes the impeller body, impeller casing, and intake bypass recirculation structure; The impeller casing circumferentially encloses the impeller body in the middle; The impeller casing includes a leading edge impeller casing and a trailing edge impeller casing arranged sequentially along the axial direction. An air inlet gap is provided between the leading edge impeller casing and the trailing edge impeller casing. The gap between the impeller body and the leading edge impeller casing and the trailing edge impeller casing constitutes the centrifugal compressor blade tip gap. The leading edge impeller casing includes a plurality of leading edge impeller casing units evenly distributed along the circumference. Each of the leading edge impeller casing units is connected end to end along the circumference, and each pair of adjacent leading edge impeller casing units is connected by a labyrinth sealing structure. The intake bypass recirculation structure includes a recirculation structure outer wall, which is arranged around the outside of the impeller casing. The trailing edge of the recirculation structure outer wall is fixedly connected to the trailing edge impeller casing. A recirculation structure chamber is formed between the recirculation structure outer wall and the impeller casing. The intake gap connects the centrifugal compressor blade tip gap and the recirculation structure chamber. Each of the aforementioned leading edge impeller casing units has a leading edge impeller casing fixing structure fixedly provided on its outer side wall. The outer wall of the recirculation structure has a fixing structure cavity that corresponds one-to-one with each of the aforementioned leading edge impeller casing fixing structures. The leading edge impeller casing fixing structure and the fixing structure cavity are nested and connected. Each of the aforementioned leading edge impeller casing fixing structures is provided with a radial adjustment mechanism for adjusting the radial position of the leading edge impeller casing fixing structure.
2. The adjustable centrifugal compressor impeller casing structure according to claim 1, characterized in that: The leading edge impeller casing includes six leading edge impeller casing units evenly distributed circumferentially.
3. The adjustable centrifugal compressor impeller casing structure according to claim 1, characterized in that: The radial adjustment mechanism includes a lead screw and a lead screw knob. The lead screw is rotatably connected to the outer wall of the recirculation structure and is radially fixed relative to the outer wall of the recirculation structure. The leading edge impeller housing fixing structure is provided with a threaded hole that is threadedly connected to the lead screw. The lead screw knob is connected to the radially outward end of the lead screw and is used to rotate the lead screw.
4. The adjustable centrifugal compressor impeller casing structure according to claim 1, characterized in that: A limiting protrusion is fixedly provided on the inner side of the fixed structure cavity, and an annular limiting groove corresponding to the limiting protrusion is provided on the leading edge impeller cover fixing structure. The limiting protrusion is disposed in the annular limiting groove with clearance fit.
5. The adjustable centrifugal compressor impeller casing structure according to claim 1, characterized in that: The leading edge impeller casing fixing structure includes an axially inclined elliptical structure or a streamlined structure; the fixing structure cavity is a structural cavity adapted to the shape of the leading edge impeller casing fixing structure.
6. The adjustable centrifugal compressor impeller casing structure according to claim 3, characterized in that: The lead screw is rotatably connected to the outer wall of the recycling structure via a bearing.
7. The adjustable centrifugal compressor impeller casing structure according to claim 3, characterized in that: The lead screw knob is sleeved on the lead screw and connected to the lead screw via a flat key.
8. The adjustable centrifugal compressor impeller casing structure according to claim 1, characterized in that: The outer wall of the recirculation structure, the tail impeller cover, and the fixed structure cavity are an integral structure.
9. The adjustable centrifugal compressor impeller casing structure according to claim 1, characterized in that: The leading edge impeller housing unit and the leading edge impeller housing fixing structure thereon are an integral structure.
Citation Information
Patent Citations
Centrifugal compressor for use with low global warming potential (GWP) refrigerant
CN114080507A
Guide wheel recirculator for mixed fluid booster
CN2804446Y