Centrifugal impeller and centrifugal compressor

Abstract

The present invention discloses a centrifugal impeller and a centrifugal compressor, comprising an impeller body, a support ring arranged on the back surface of the impeller body, and a mounting ring arranged on the support ring and extending toward the center of the impeller body, the back surface of the impeller body, the support ring and the mounting ring forming a groove, a plurality of mounting holes evenly distributed along the circumference of the mounting ring, a counterweight structure arranged in at least one of the mounting holes, the counterweight structure comprising a counterweight head adapted to the groove, a limiting plate connected to one end of the counterweight head and a counterweight pin, a positioning hole corresponding to the mounting hole being provided on the counterweight head, the counterweight pin passing through the mounting hole and connected to the positioning hole, and the limiting plate blocking the counterweight pin after being bent; the structure is simple, the assembly and disassembly is convenient, the versatility is strong, and the adjustment range is wide, so that the centrifugal impeller can be repeatedly used.

Description

Technical Field

[0001] The present invention relates to the technical field of aero-engines, and in particular to a centrifugal impeller. In addition, the present invention also relates to a centrifugal compressor comprising the centrifugal impeller. Background Art

[0002] Centrifugal compressors are widely used in small and medium-sized aircraft engines due to their advantages, such as simple structure, high single-stage compression ratio, and wide stable operating range. The centrifugal impeller is a key component of the centrifugal compressor. Due to its high rotational speed, dynamic balancing of the centrifugal impeller is crucial for its operation. Dynamic balancing primarily reduces energy loss and improves efficiency; reduces vibration during operation and extends the impeller's service life; and reduces the risk of wear and fatigue, minimizing failures and improving reliability.

[0003] like Figure 1 As shown, the existing centrifugal impeller achieves dynamic balancing adjustment by removing material from the protruding structure arranged on its back surface. On the one hand, since the unremoved part of the protruding structure will increase the weight of the rotor and reduce efficiency during use, the protruding structure is generally designed with a limited weight and a small adjustable range, which makes it difficult to meet the dynamic balancing adjustment requirements of the entire engine rotor; on the other hand, when the rotor is assembled for the second time (such as structural changes or installation of different turbines), it is necessary to perform dynamic balancing adjustment again based on the original removed centrifugal impeller. Since the removal operation is irreversible, it may make it difficult to achieve dynamic balancing adjustment of the centrifugal impeller, reducing the scope of application of the centrifugal impeller and increasing production costs.

[0004] The centrifugal impeller back cavity is an inherent structure of the centrifugal compressor. The flow within the cavity is a complex rotating-static disc cavity flow with inlet pre-swirl, characterized by a large radial pressure gradient, significant sudden expansion and contraction effects, and the presence of vortex flow within the cavity. The gas flow characteristics of the centrifugal impeller back cavity have a significant impact on the axial force of the engine rotor and the heat exchange of the impeller disc. On the other hand, it also affects the overall performance of the centrifugal compressor. If the airflow is not smooth, it will lead to reduced compressor efficiency and may also cause vibration, thereby affecting the performance and life of the entire engine. Therefore, adjusting the flow characteristics of the impeller back cavity is of great significance for improving the working efficiency and stability of the compressor, optimizing engine performance, and extending engine life.

[0005] Existing centrifugal compressors do not have the ability to regulate back cavity flow. Their regulation is often achieved through complex structures of other parts. The impeller back cavity structure is limited by the structure of the stator and does not have the ability to regulate swirl. Summary of the Invention

[0006] The present invention provides a centrifugal impeller and a centrifugal compressor to solve the technical problem that the centrifugal impeller has a small dynamic balance adjustment range, cannot be repeatedly used, and has obvious disadvantages during use.

[0007] According to one aspect of the present invention, a centrifugal impeller is provided, comprising an impeller body, a support ring arranged on the back surface of the impeller body, and a mounting ring arranged on the support ring and extending toward the center of the impeller body, the back surface of the impeller body, the support ring and the mounting ring forming a groove, a plurality of mounting holes evenly distributed along the circumference of the mounting ring, a counterweight structure being arranged in at least one of the mounting holes, the counterweight structure comprising a counterweight head adapted to the groove, a limiting plate connected to one end of the counterweight head, and a counterweight pin, a positioning hole corresponding to the mounting hole being provided on the counterweight head, the counterweight pin passing through the mounting hole and connected to the positioning hole, and the limiting plate being bent to block the counterweight pin.

[0008] Furthermore, the radius height of the support ring is 2 / 3 of the outer radius of the impeller body.

[0009] Furthermore, the limiting plate is vertically connected to one end of the counterweight head.

[0010] Furthermore, an internal thread is provided on the inner wall of the mounting hole and / or the positioning hole, and an external thread matching the internal thread is provided on the counterweight pin.

[0011] Furthermore, a guide surface is provided on the free end of the mounting ring and / or the free end of the counterweight head.

[0012] A centrifugal compressor comprises the centrifugal impeller mentioned above and a stator casing. A flow regulating structure and a swirl regulating structure are arranged between the impeller body and the stator casing.

[0013] Furthermore, the flow regulating structure includes a plurality of grate teeth arranged on the impeller body and a sealing ring arranged on the stator casing, and the grate teeth are clearance-matched with the sealing ring.

[0014] Furthermore, a wear-resistant layer is provided on the side of the sealing ring facing the comb teeth.

[0015] Furthermore, the grate tooth gap between the grate teeth and the sealing ring is 0.2-0.6 mm, the tooth spacing between two adjacent grate teeth is 2.7 mm, and the thickness of the wear-resistant layer is 0.05-0.15 mm.

[0016] Furthermore, the swirl adjustment structure includes a support plate arranged on the stator casing and an adjustment plate arranged on the support plate. The adjustment plate extends radially toward the sealing ring, and the size conversion of the back cavity is achieved by adjusting the axial position of the adjustment plate.

[0017] The present invention has the following beneficial effects:

[0018] The centrifugal impeller of the present invention, during the dynamic balancing adjustment process, if it is necessary to add weight at a certain circumferential position, the counterweight head is inserted into the groove, the counterweight pin is inserted into the positioning hole after passing through the mounting hole, and then the limit plate is bent to wrap the support ring and block the counterweight pin, so as to prevent the counterweight pin from loosening; during the secondary assembly of the rotor, for some counterweight structures that need to be disassembled, the limit plate is straightened, and the counterweight pin can be taken out after exposing the counterweight pin, thereby removing the counterweight head from the groove. It has a simple structure, is easy to assemble and disassemble, has strong versatility, and a wide adjustment range, so that the centrifugal impeller can be repeatedly used many times; during use, the counterweight structure will press the support ring upward due to the action of centrifugal force, thereby increasing its stability when rotating at high speed, and can be suitable for high-speed usage scenarios; the support ring, mounting ring and counterweight structure are arranged inside the impeller back cavity away from the main airflow, and have little effect on the gas flow state in the main channel, which can reduce the influence of the structure on the aerodynamic efficiency and stability of the engine.

[0019] In addition to the above-described objects, features and advantages, the present invention has other objects, features and advantages. The present invention will be further described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0021] Figure 1 It is a structural diagram of an existing centrifugal impeller;

[0022] Figure 2 1 is a schematic structural diagram of an impeller body according to a preferred embodiment of the present invention;

[0023] Figure 3 is a schematic structural diagram of a mounting ring according to a preferred embodiment of the present invention;

[0024] Figure 4 This is a schematic structural diagram of a counterweight pin according to a preferred embodiment of the present invention;

[0025] Figure 5 is a cross-sectional view of a counterweight head according to a preferred embodiment of the present invention;

[0026] Figure 6 is a side view of a counterweight head according to a preferred embodiment of the present invention;

[0027] Figure 7 is a structural schematic diagram of a counterweight structure according to a preferred embodiment of the present invention;

[0028] Figure 81 is a schematic structural diagram of a centrifugal impeller according to a preferred embodiment of the present invention;

[0029] Figure 9 is a structural diagram of a flow regulating structure according to a preferred embodiment of the present invention;

[0030] Figure 10 2 is a schematic structural diagram of a swirl regulating structure according to a preferred embodiment of the present invention;

[0031] Figure 11 Schematic diagram of the temperature of the impeller body under different grate gaps in a preferred embodiment of the present invention, wherein: Figure 11 The gap between the teeth of (a) is 0.3 mm. Figure 11 (b) The grate tooth gap is 0.4 mm;

[0032] Figure 12 : is a vortex structure diagram of different sizes of impeller disc cavities in a preferred embodiment of the present invention, wherein: Figure 12 (a) The vortex structure corresponding to the large cavity, Figure 12 (b) Vortex structure diagram corresponding to the small cavity;

[0033] Figure 13 : is a swirl coefficient distribution diagram of impeller disc cavities of different sizes in a preferred embodiment of the present invention, wherein: Figure 13 (a) The swirl coefficient distribution corresponding to the large cavity, Figure 13 (b) Distribution of swirl coefficient corresponding to the small cavity.

[0034] Legend:

[0035] 1. Impeller body; 11. Support ring; 12. Mounting ring; 121. Mounting hole; 13. Groove; 2. Counterweight structure; 21. Counterweight head; 211. Positioning hole; 212. Guide surface; 22. Limit plate; 23. Counterweight pin; 3. Stator casing; 4. Flow adjustment structure; 41. Grate teeth; 42. Sealing ring; 421. Wear-resistant layer; 5. Swirl adjustment structure; 51. Support plate; 52. Adjustment plate; 6. Impeller back cavity. DETAILED DESCRIPTION

[0036] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways as defined and covered below.

[0037] like Figures 2 to 8As shown, the centrifugal impeller of this embodiment includes an impeller body 1, a support ring 11 arranged on the back surface of the impeller body 1, and a mounting ring 12 arranged on the support ring 11 and extending toward the center of the impeller body 1. The back surface of the impeller body 1, the support ring 11 and the mounting ring 12 form a groove 13. A plurality of mounting holes 121 are evenly distributed along the circumference of the mounting ring 12. A counterweight structure 2 is arranged in at least one of the mounting holes 121. The counterweight structure 2 includes a counterweight head 21 adapted to the groove, a limiting plate 22 connected to one end of the counterweight head 21, and a counterweight pin 23. A positioning hole 211 corresponding to the mounting hole 121 is opened on the counterweight head 21. The counterweight pin 23 passes through the mounting hole 121 and is connected to the positioning hole 211. The limiting plate 22 is bent to block the counterweight pin 23.

[0038] During the dynamic balancing adjustment process of the centrifugal impeller of this embodiment, if it is necessary to add weight at a certain circumferential position, the counterweight head 2 is inserted into the groove 13, the counterweight pin 23 passes through the mounting hole 121 and is inserted into the positioning hole 211, and then the limiting plate 22 is bent to wrap around the support ring 11 and block the counterweight pin 23, so as to prevent the counterweight pin 23 from loosening; during the secondary assembly of the rotor, for the counterweight structure 2 that needs to be disassembled, the limiting plate 22 is straightened, and the counterweight pin 23 can be taken out after the counterweight pin 23 is exposed, thereby removing the counterweight head 21 from the rotor. It can be taken out from the groove 13. It has a simple structure, is easy to assemble and disassemble, has strong versatility and a wide adjustment range, so that the centrifugal impeller can be repeatedly used. During use, the counterweight structure 2 will press the support ring 11 upward due to the action of centrifugal force, which increases its stability when rotating at high speed and can be used in high-speed use scenarios. The support ring 11, the mounting ring 12 and the counterweight structure 2 are arranged inside the impeller back cavity 6 away from the main airflow, and have little effect on the gas flow state in the main channel, which can reduce the impact of the structure on the aerodynamic efficiency and stability of the engine. Optionally, by setting counterweight heads 21 of different thicknesses to form different weight specifications, the adjustment range can be further improved. Optionally, the counterweight head 21 and / or the counterweight pin 23 are made of materials of different densities to form different weight specifications, which can further improve the adjustment range.

[0039] In this embodiment, the radius height of the support ring 11 is 2 / 3 of the outer radius of the impeller body 1. Since the imbalance amount is the product of the unbalanced mass and the radius, setting the support ring 11 at a high radius position can increase the adjustment range of the imbalance amount.

[0040] like Figure 5 As shown, in this embodiment, the limit plate 22 is vertically connected to one end of the counterweight head 21. When the counterweight head 21 is inserted into the groove 13, the raised limit plate 22 only needs to bend once to cover the counterweight pin 23, which can improve assembly efficiency.

[0041] In this embodiment, the inner walls of the mounting hole 121 and / or the positioning hole 211 are provided with internal threads, and the counterweight pin 23 is provided with external threads that match the internal threads, which further enhances the stability of the counterweight structure 2 and prevents the counterweight structure 2 from shaking. Optionally, the head of the counterweight pin 23 is provided with a slot, a cross slot, or a hexagonal slot, and the counterweight pin 23 is tightened using a suitable tool, resulting in a simple structure and convenient operation.

[0042] like Figure 5 As shown, in this embodiment, a guide surface 212 is provided on the free end of the mounting ring 12 and / or the free end of the counterweight head 21, which can guide the counterweight head 21 to be quickly inserted into the groove 13, thereby improving assembly efficiency and avoiding scratches.

[0043] like Figure 8 As shown, in this embodiment, the number of mounting holes 121 on the centrifugal impeller of a certain type of engine is 30, the diameter of the mounting hole 121 is 2.2mm, and the tolerance is 0 to +0.1mm; the diameter of the counterweight pin 23 is 2.2mm, and the tolerance is -0.03 to -0.01mm; the diameter of the positioning hole 211 is 2.2mm, and the tolerance is 0 to +0.1mm; during the adjustment process, four counterweight blocks are installed, and the assembly position is as shown in FIG. Figure 8 As shown, the dynamic balancing speed was adjusted to 1800r / min, and the residual unbalance after balancing did not exceed 6g.mm at this adjustment position. The engine test was carried out using the rotor after dynamic balancing adjustment. The test ran for a total of 2000h and the maximum transient speed reached 50000r / min. During the test, the engine vibration was always within the planned limit range, and no parts wear and fatigue failure were found in the disassembly inspection after the test.

[0044] like Figure 2 、 Figure 9 and Figure 10 As shown, the centrifugal compressor of this embodiment includes the above-mentioned centrifugal impeller and a stator casing 3. A flow regulating structure 4 and a swirl regulating structure 5 are arranged between the impeller body 1 and the stator casing 3. Through the combined use of the flow regulating structure 4 and the swirl regulating structure 5, continuous regulation of flow and pressure within a very wide range can be achieved, meeting the large-scale regulation requirements of the engine rotor axial force and the impeller disc heat exchange.

[0045] like Figure 9 As shown, in this embodiment, the flow regulating structure 4 includes a plurality of grate teeth 41 arranged on the impeller body 1 and a sealing ring 42 arranged on the stator casing 3, and the grate teeth 41 and the sealing ring 42 are clearance-matched; the grate teeth 41 and the impeller body 1 are integrated into a design, and the back cavity flow and pressure regulation capability is achieved by adjusting the grate tooth gap between the grate teeth 41 and the sealing ring 42. The structure is simple, the number of parts is small, and the adjustment method is simple and easy to implement.

[0046] like Figure 9 As shown, in this embodiment, a wear-resistant layer 421 is provided on the side of the sealing ring 42 facing the grate teeth 41. The grate tooth gap is adjusted by directly grinding the tooth tips of the grate teeth 41 or adjusting the thickness of the wear-resistant layer 421. The operation is convenient and rapid adjustment within a small range can be achieved.

[0047] In this embodiment, the gap between the grate teeth 41 and the sealing ring 42 is 0.2-0.6 mm, the tooth spacing between two adjacent grate teeth 41 is 2.7 mm, and the thickness of the wear-resistant layer 421 is 0.05-0.15 mm.

[0048] In this embodiment, a temperature diagram of the impeller disk when the grate gap of the flow regulating structure 4 is 0.3 mm and 0.4 mm respectively is obtained by simulation, as shown in FIG. Figure 11 As shown in the figure, it can be seen that the temperature at the grate position is reduced by about 20℃ under large gap conditions.

[0049] like Figure 10 As shown, in this embodiment, the swirl regulating structure 5 includes a support plate 51 arranged on the stator casing 3 and an adjusting plate 52 arranged on the support plate 51, and the adjusting plate 52 extends radially toward the sealing ring 42, and the size conversion of the back cavity is achieved by adjusting the axial position of the adjusting plate 52; one end of the support plate 51 is connected to the stator casing 3, and the other end is connected to the sealing ring 42. By assembling the adjusting plates 52 with different axial positions, the free conversion of the large cavity and the small cavity of the impeller back cavity 6 is achieved. Since the size structure of the back cavity directly affects the flow vortex structure of the fluid, the swirl of the back cavity fluid is regulated by controlling the size of the back cavity, thereby achieving the regulation function of the back cavity flow and pressure.

[0050] In this embodiment, the flow characteristics of the large cavity and the small cavity under the structure of the grate tooth gap of 0.3mm are obtained by simulation. Figure 12 and Figure 13 As shown in the figure, it can be seen that the flow vortex structures of the two schemes are quite different, which also leads to differences in the swirl coefficients: in the fluid core area at the bottom of the large cavity, the swirl coefficient is generally around 0.5; in the fluid core area at the bottom of the small cavity, the swirl coefficient is mostly above 0.6. It can be seen that the swirl regulating structure 5 has a good swirl regulating effect, and the swirl coefficient has a direct impact on the back cavity flow and pressure. Therefore, changing the axial position of the regulating plate 52 can achieve the purpose of flow and pressure regulation.

[0051] In this embodiment, the flow calculation results of the impeller back cavity with different structures under specific working conditions were obtained by simulation, as shown in Table 1.

[0052] Table 1 Calculation results of impeller back cavity flow under different structures Unit: g / s

[0053] Small cavity Large cavity Grate tooth gap 0.3mm 21.3 28.3 Grate tooth gap 0.4mm 27.6 34.8

[0054] As can be seen from the table, increasing the back cavity flow rate can be achieved by either increasing the grate gap or enlarging the disc cavity. Increasing the grate gap by 0.1 mm or enlarging the disc cavity can achieve a regulation effect of 6 to 7 g / s. Using both regulation methods simultaneously can achieve a combined effect of approximately 13 g / s. Simulation results demonstrate that the two flow regulation methods of the present invention can be combined to achieve a wider range of flow regulation.

[0055] In this embodiment, the axial force of the back cavity of the impeller with different structures under specific working conditions was obtained by simulation (since the axial force depends on the product of the back cavity pressure and the corresponding area, the pressure size and distribution of the back cavity directly affect the size of the axial force) calculation results are shown in Table 2.

[0056] Table 2 Calculation results of impeller back axial force under different structures Unit: N

[0057] Small disc cavity Large disc cavity Grate tooth gap 0.3mm 27109 26292 Grate tooth gap 0.4mm 26448 25659

[0058] Table 2 shows that increasing the grate gap or enlarging the disc cavity can both reduce the impeller's back-axial force. Increasing the grate gap by 0.1 mm or enlarging the disc cavity can achieve a regulation effect of 600 N to 800 N. Using both regulation methods simultaneously can achieve a combined effect of approximately 1450 N. Simulation results demonstrate that the two pressure regulation methods of the present invention can be combined to achieve a wider range of pressure regulation.

[0059] The centrifugal compressor of the present invention achieves large-scale dynamic balance adjustment by installing a counterweight structure 2 on the mounting hole 121 on the mounting ring 12. The counterweight structure 2 can be reused many times without affecting the engine efficiency and is a dynamic balance adjustment structure suitable for high speeds. The counterweight structure 2 on the impeller body 1 is at a high radius position and has a large adjustment range. The impeller body 1 is integrated with a comb 41, and the air flow and pressure of the impeller back cavity 6 are adjusted by controlling the comb gap between the tooth tip of the comb 41 and the sealing ring 42. The large and small cavities of the impeller back cavity 6 can be freely converted by installing adjustment plates 52 with different axial positions to achieve the swirl adjustment function, thereby achieving the adjustment of the flow and pressure parameters of the impeller back cavity 6. In particular, the combination of the flow adjustment structure 4 and the swirl adjustment structure 5 can have superimposed adjustment functions, thereby having a larger parameter adjustment range. The centrifugal compressor has the advantages of a wide range of application, high applicable speed, multiple adjustment parameters, a large adjustment range, a simple adjustment method, and low processing cost.

[0060] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A centrifugal impeller, characterized in that: The invention comprises an impeller body (1), a support ring (11) arranged on the back surface of the impeller body (1), and a mounting ring (12) arranged on the support ring (11) and extending toward the center of the impeller body (1), wherein the back surface of the impeller body (1), the support ring (11) and the mounting ring (12) form a groove (13), and the mounting ring (12) is uniformly distributed along the circumference with a plurality of mounting holes (121), and a counterweight is arranged in at least one of the mounting holes (121). The counterweight structure (2) comprises a counterweight head (21) adapted to the groove (13), a limiting plate (22) connected to one end of the counterweight head (21), and a counterweight pin (23); the counterweight head (21) is provided with a positioning hole (211) corresponding to the mounting hole (121); the counterweight pin (23) passes through the mounting hole (121) and is connected to the positioning hole (211); and the limiting plate (22) is bent to block the counterweight pin (23).

2. The centrifugal impeller according to claim 1, characterized in that: The radius height of the support ring (11) is 2 / 3 of the outer radius of the impeller body (1).

3. The centrifugal impeller according to claim 1 or 2, characterized in that: The limiting plate (22) is vertically connected to one end of the counterweight head (21).

4. The centrifugal impeller according to claim 3, characterized in that: Internal threads are provided on the inner walls of the mounting hole (121) and / or the positioning hole (211), and external threads matching the internal threads are provided on the counterweight pin (23).

5. The centrifugal impeller according to claim 4, characterized in that: A guide surface (212) is provided on the free end of the mounting ring (12) and / or the free end of the counterweight head (21).

6. A centrifugal compressor, characterized in that: The invention comprises a centrifugal impeller according to any one of claims 1 to 5, and further comprises a stator casing (3), wherein a flow regulating structure (4) and a swirl regulating structure (5) are arranged between the impeller body (1) and the stator casing (3).

7. The centrifugal compressor according to claim 6, characterized in that: The flow regulating structure (4) comprises a plurality of grate teeth (41) arranged on the impeller body (1) and a sealing ring (42) arranged on the stator casing (3), wherein the grate teeth (41) and the sealing ring (42) are clearance-matched.

8. The centrifugal compressor according to claim 7, characterized in that: A wear-resistant layer (421) is provided on the side of the sealing ring (42) facing the comb teeth (41).

9. The centrifugal compressor according to claim 8, characterized in that: The grate tooth gap between the grate teeth (41) and the sealing ring (42) is 0.2-0.6 mm, the tooth spacing between two adjacent grate teeth (41) is 2.7 mm, and the thickness of the wear-resistant layer (421) is 0.05-0.15 mm.

10. The centrifugal compressor according to claim 7, characterized in that: The swirl regulating structure (5) comprises a support plate (51) arranged on the stator casing (3) and an adjusting plate (52) arranged on the support plate (51); the adjusting plate (52) extends radially toward the sealing ring (42); and the size conversion of the back cavity is achieved by adjusting the axial position of the adjusting plate (52).

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