Centrifugal impeller

Abstract

This invention relates to the field of aero-engine technology, specifically to centrifugal impellers. The centrifugal impeller includes: a body comprising a shaft hole and a plurality of blades spaced circumferentially along the shaft hole; a first air hole and a second air hole, respectively disposed on both sides of the blades along the axial direction of the body and communicating with the shaft hole to form a gas passage; and a first sealing structure disposed on the body and corresponding to the first air hole, allowing high-pressure gas to flow out from the first sealing structure. In the centrifugal impeller of this invention, when the high-pressure, high-speed airflow flows along the back of the centrifugal impeller, it enters the shaft hole of the body through the second air hole, and then flows out from the first sealing structure through the first air hole, thereby forming a high-pressure gas chamber. The pressure difference between the inside and outside of the chamber ensures that the lubricating oil near the first air hole does not leak into the flow channel. Because the first air hole, shaft hole, and second air hole are all integrally formed on the body, no additional structures are required, thus reducing processing costs and cycle time while achieving the air intake function.

Description

Technical Field

[0001] This invention relates to the field of aero-engine technology, and more specifically to centrifugal impellers. Background Technology

[0002] With the development of general aviation propulsion, the need for low-cost, miniaturized, and lightweight aero engines has become increasingly urgent. Existing centrifugal impellers have low integration levels and simple functions, often requiring the design of other components to meet other engine performance requirements. This increases manufacturing costs, engine size and weight, and processing and assembly cycles. Summary of the Invention

[0003] This invention provides a centrifugal impeller to solve the problems of high manufacturing cost and long processing and assembly cycle of existing centrifugal impellers.

[0004] This invention provides a centrifugal impeller, comprising: The body includes a shaft hole and multiple blades spaced apart circumferentially along the shaft hole; The first and second air holes are respectively arranged on both sides of the blade along the axial direction of the body, and both are connected to the shaft hole to form a gas channel. The first sealing structure is located on the main body and is positioned corresponding to the first vent, so that high-pressure gas can flow out from the first sealing structure.

[0005] Beneficial effects: When the high-pressure, high-speed airflow flows along the back of the centrifugal impeller, it enters the shaft hole of the main body through the second air hole, and then flows out through the first air hole from the first sealing structure, thus forming a high-pressure air chamber. The pressure difference between the inside and outside of the chamber ensures that the lubricating oil near the first air hole will not leak into the flow channel. Because the first air hole, shaft hole, and second air hole are all integrally formed on the main body, no additional structures are needed. Therefore, while fulfilling the air-entraining function, processing costs and cycle time are reduced.

[0006] In one alternative embodiment, a second sealing structure is further provided on the body, and along the axial direction of the body, the second vent is located between the blade and the second sealing structure.

[0007] The second sealing structure works in conjunction with the first sealing structure to precisely control the pressure distribution on both sides of the impeller, significantly stabilizing the axial force; it also reduces leakage on both sides, significantly improving the overall efficiency; and it suppresses airflow vibration, enhancing the stability of the rotor system.

[0008] In one optional embodiment, both the first sealing structure and the second sealing structure include two sets of helical teeth with opposite inclination directions along the axial direction of the body, and the gas flow direction is opposite to the inclination direction of the helical teeth.

[0009] The inclined direction of the helical teeth is opposite to the direction of gas flow, which can cause the gas to actively flow in the opposite direction, significantly improving the sealing performance and reducing leakage.

[0010] In one optional embodiment, the angle of the helical teeth is 15°-20°, and the angle between the helical teeth and the axis of the body is 45°-60°.

[0011] The aforementioned helical teeth configuration makes it more difficult for fluid to "flow smoothly" within the sealed cavity by altering the airflow direction, enhancing vortex dissipation, reducing the effective flow area, and weakening the return channel, thereby significantly reducing leakage.

[0012] In one alternative implementation, the first vent is located between two sets of helical teeth of the first sealing structure.

[0013] High-pressure airflow flows out from the center of the two sets of helical teeth of the first sealing structure, which can form a stable air seal barrier in the sealing gap, effectively blocking the direct leakage of high-pressure fluid along the sealing gap. At the same time, it increases the pressure and aerodynamic damping of the sealing cavity, suppresses airflow vibration, balances the pressure distribution on both sides of the impeller, reduces axial force fluctuation, and improves the stability of the rotor system and the overall efficiency of the machine.

[0014] In one optional embodiment, the blade includes a first blade and a second blade spaced apart circumferentially, and the length of the first blade is 50%-70% of the length of the second blade along the axial direction of the body.

[0015] By configuring the centrifugal impeller blades into combinations of long and short blades of different lengths, the internal flow channels of the impeller can be effectively divided without increasing the number of inlet blades or avoiding inlet blockage. This suppresses the separation of secondary flow and airflow, reduces flow losses, improves the impeller's work capacity and the uniformity of the outlet flow field, thereby enhancing aerodynamic efficiency and operational stability. At the same time, it reduces aerodynamic noise, expands the stable operating range, and improves pressure ratio and efficiency.

[0016] In one alternative implementation, the ratio of the number of the first blade to the number of the second blade is 1:1.

[0017] The use of the same number of long and short blades in a uniform staggered arrangement allows the impeller to form a completely symmetrical flow channel structure and flow field distribution in the circumferential direction, effectively eliminating aerodynamic imbalance forces and periodic pressure pulsations, reducing rotor vibration and noise, while ensuring consistent flow state in each flow channel, and improving impeller aerodynamic efficiency, operational stability and structural fatigue life.

[0018] In one optional embodiment, along the axial direction of the body, external splines and internal splines are respectively provided on both sides of the blade. The external splines are located near the first air hole and are suitable for spline connection with the drive shaft, while the internal splines are located near the second air hole and are suitable for connection with the turbine disk.

[0019] The external spline is connected to the drive shaft spline, which can directly output torque; the internal spline is connected to the turbine disk, which drives the centrifugal impeller to rotate and is the power source for the centrifugal impeller.

[0020] In one optional embodiment, along the axial direction of the body, a shaft positioning surface and a spline positioning surface are respectively provided in the shaft hole, with the shaft positioning surface located near the outer spline and the spline positioning surface located near the inner spline.

[0021] The shaft positioning surface is used for centering and installing the inner shaft of the centrifugal impeller. Applying axial force to the inner shaft can be used for pre-tightening the centrifugal impeller. The spline positioning surface is used for centering the parts. Both positioning surfaces adopt interference fit to ensure that the centrifugal impeller will not be eccentric during rotation.

[0022] In one alternative embodiment, the body is further provided with an oil-slinging hole, which is located near the first air hole.

[0023] The main function of the oil slinger hole is to ensure that there is no oil accumulation in the shaft hole. During the rotation of the centrifugal impeller, the lubricating oil in the shaft hole is thrown out through the oil slinger hole due to centrifugal force. Attached Figure Description

[0024] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of a centrifugal impeller according to an embodiment of the present invention; Figure 2 This is a schematic cross-sectional view of a centrifugal impeller; Figure 3 This is a schematic diagram of high-pressure airflow flowing in a centrifugal impeller; Figure 4 This is a schematic diagram showing the gas flow at the first sealing structure. Figure 5 This is a schematic diagram showing the gas flow at the second sealing structure. Figure 6 This is a schematic diagram of the helical gear structure.

[0026] Explanation of reference numerals in the attached figures: 1. Body; 101. Shaft hole; 102. Blade; 1021. First blade; 1022. Second blade; 103. Bushing; 2. First vent; 3. Second vent; 4. First sealing structure; 5. Second sealing structure; 6. External spline; 7. Internal spline; 8. External thread; 9. Shaft positioning surface; 10. Spline positioning surface; 11. Oil slinger hole. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] The following is combined Figures 1 to 6 Embodiments of the present invention are described.

[0029] According to an embodiment of the present invention, a centrifugal impeller is provided, which adopts an integrated design and has functions such as pressurization, speed increase, centering, torque transmission, sealing, air evacuation, and oil slinging. It can effectively reduce costs, decrease the number of parts, reduce size and weight, and shorten the processing and assembly cycle. The impeller includes: The body 1 includes a shaft hole 101 and a plurality of blades 102 distributed circumferentially along the shaft hole 101; The first pore 2 and the second pore 3 are respectively arranged on both sides of the blade 102 along the axial direction of the body 1, and both are connected to the shaft hole 101 to form a gas channel. The first sealing structure 4 is provided on the body 1 and is correspondingly provided with the first vent 2 so that high-pressure gas flows out from the first sealing structure 4.

[0030] like Figure 1 As shown, the main body 1 is a one-piece machined metal part with a centrally located bushing 103. A shaft hole 101 is formed in the center of the bushing 103 for mounting a shaft. Multiple blades 102 are circumferentially arranged at one end of the bushing 103, thus forming a centrifugal impeller. Figure 2 As shown, the blade 102 has a first air hole 2 and a second air hole 3 on its left and right sides, respectively, and both are located close to the blade 102. The first air hole 2 and the second air hole 3 can be multiple holes spaced apart along the circumference, or they can be a single annular hole; no specific limitation is made here. The first sealing structure 4 consists of multiple annular rings spaced apart along the axial direction of the body 1, and distributed on both sides of the first air hole 2.

[0031] Beneficial effects: When the high-pressure, high-speed airflow flows along the back of the centrifugal impeller, it enters the shaft hole 101 of the body 1 through the second air hole 3, and then flows out through the first sealing structure 4 through the first air hole 2, thus forming a high-pressure air chamber. Through the pressure difference between the inside and outside, the lubricating oil near the first air hole 2 is prevented from leaking into the flow channel. Since the first air hole 2, the shaft hole 101, and the second air hole 3 are all integrally formed on the body 1, no other structures need to be added. Therefore, while playing the role of air intake, the processing cost and cycle are reduced.

[0032] In one embodiment, a second sealing structure 5 is provided on the body 1, and along the axial direction of the body 1, the second vent 3 is located between the blade 102 and the second sealing structure 5.

[0033] like Figure 2 As shown, the second sealing structure 5 is located on the right side of the impeller and is basically completely distributed on the right side bushing 103. It is also a plurality of rings spaced apart along the axial direction of the body 1.

[0034] The second sealing structure 5 works in conjunction with the first sealing structure 4 to precisely control the pressure distribution on both sides of the impeller, significantly stabilizing the axial force; it also reduces leakage on both sides, significantly improving the overall efficiency; and it suppresses airflow vibration, enhancing the stability of the rotor system.

[0035] In one embodiment, both the first sealing structure 4 and the second sealing structure 5 include two sets of helical teeth that are tilted in opposite directions along the axial direction of the body 1, and the gas flow direction is opposite to the tilt direction of the helical teeth.

[0036] like Figure 2 and Figure 3 As shown, the two sets of helical teeth in the first sealing structure 4 and the second sealing structure 5 are symmetrically arranged, with a certain gap reserved in between. Figure 4 As shown, after the high-pressure gas flows out of the first vent 2, it flows to the left and right sides respectively, and the two sets of helical teeth of the first sealing structure 4 are inclined towards the direction of the first vent 2; as Figure 5 As shown, when the external gas reaches the second sealing structure 5, it flows to the left and right sides respectively. The gas on the left enters the shaft hole 101 through the second air hole 3, while the gas on the right continues to flow to the right. The two sets of helical teeth of the second sealing structure 5 are symmetrically inclined towards the center.

[0037] The inclined direction of the helical teeth is opposite to the direction of gas flow, which can cause the gas to actively flow in the opposite direction, significantly improving the sealing performance and reducing leakage.

[0038] In one embodiment, the angle B of the helical tooth is 15°-20°, and the angle A between the helical tooth and the axial direction of the body 1 is 45°-60°.

[0039] The angle of the helical teeth and the angle between the helical teeth and the axis of the body 1 can be selected from any value within the above range according to actual needs, and no specific restrictions are imposed here.

[0040] The aforementioned helical teeth configuration makes it more difficult for fluid to "flow smoothly" within the sealed cavity by altering the airflow direction, enhancing vortex dissipation, reducing the effective flow area, and weakening the return channel, thereby significantly reducing leakage.

[0041] In one embodiment, the first vent 2 is located between two sets of helical teeth of the first sealing structure 4.

[0042] like Figure 4 As shown, the first air hole 2 is located exactly in the center of the two symmetrically arranged helical teeth, that is, the two sets of helical teeth wrap around the first air hole 2. In this way, the high-pressure airflow flows out from the center of the two sets of helical teeth of the first sealing structure 4, which can form a stable air seal barrier in the sealing gap, effectively blocking the direct leakage of high-pressure fluid along the sealing gap. At the same time, it increases the sealing cavity pressure and aerodynamic damping, suppresses airflow vibration, balances the pressure distribution on both sides of the impeller, reduces axial force fluctuation, and improves the stability of the rotor system and the overall efficiency of the machine.

[0043] In one embodiment, the blade 102 includes a first blade 1021 and a second blade 1022 arranged circumferentially, and along the axial direction of the body 1, the length of the first blade 1021 is 50%-70% of the length of the second blade 1022.

[0044] like Figure 1 As shown, a first blade 1021 is provided in the center of the flow channel formed by two adjacent second blades 1022. One end of the first blade 1021 and the second blade 1022 are located at the outer edge of the same circle, and the other end extends toward the center of the impeller. The extension length of the first blade 1021 is less than the extension length of the second blade 1022, thus forming a pattern of large blades and small blades distributed alternately.

[0045] By configuring the centrifugal impeller blades into a combination of long and short blades 102 of different lengths, the internal flow channel of the impeller can be effectively divided without increasing the number of inlet blades or avoiding inlet blockage. This suppresses the separation of secondary flow and airflow, reduces flow loss, improves the impeller's work capacity and the uniformity of the outlet flow field, thereby improving aerodynamic efficiency and operational stability. At the same time, it reduces aerodynamic noise, expands the stable operating range, and improves pressure ratio and efficiency.

[0046] In one embodiment, the ratio of the number of first blades 1021 to the number of second blades 1022 is 1:1.

[0047] In this embodiment, it is preferred that the number of the first blade 1021 and the second blade 1022 are equal. Of course, the number of the first blade 1021 can also be set to be greater than or less than the number of the second blade 1022. No specific restrictions are imposed here.

[0048] The long and short blades 102 are arranged in the same number and in a uniform staggered manner, which can make the impeller form a completely symmetrical flow channel structure and flow field distribution in the circumferential direction. This effectively eliminates aerodynamic unbalance forces and periodic pressure pulsations, reduces rotor vibration and noise, and ensures that the flow state of each flow channel is consistent, thereby improving the impeller's aerodynamic efficiency, operational stability and structural fatigue life.

[0049] In one embodiment, along the axial direction of the body 1, an external spline 6 and an internal spline 7 are respectively provided on both sides of the blade 102. The external spline 6 is located near the first air hole 2 and is suitable for spline connection with the drive shaft. The internal spline 7 is located near the second air hole 3 and is suitable for connection with the turbine disk.

[0050] like Figure 2 As shown, the external spline 6 and the internal spline 7 are respectively located near the two ends of the bushing 103, as... Figure 1 As shown, the external spline 6 consists of multiple key teeth spaced apart circumferentially along the bushing 103, and the internal spline 7 is provided on the inner wall of the shaft hole 101. An external thread 8 is also provided between the external spline 6 and the first sealing structure 4. The external thread 8 is used to install the bearing lock nut.

[0051] The external spline 6 is connected to the drive shaft spline and can directly output torque; the internal spline 7 is connected to the turbine disk, which drives the centrifugal impeller to rotate and is the power source for the centrifugal impeller.

[0052] In one embodiment, along the axial direction of the body 1, a shaft positioning surface 9 and a spline positioning surface 10 are respectively provided in the shaft hole 101. The shaft positioning surface 9 is located on the side near the outer spline 6, and the spline positioning surface 10 is located on the side near the inner spline 7.

[0053] like Figure 2 As shown, the inner diameter of the shaft positioning surface 9 is smaller than the inner diameter of the end of the shaft hole 101, thus forming a boss-shaped positioning surface. An inclined guide surface is provided on one side of the boss. The spline positioning surface 10 is formed between two adjacent splines and is also boss-shaped with a smaller inner diameter.

[0054] Shaft positioning surface 9 is used for centering and installing the inner shaft of the centrifugal impeller. An axial force is applied to the inner shaft, which can be used for pre-tightening of the centrifugal impeller. Spline positioning surface 10 is used for centering the parts. Both positioning surfaces adopt interference fit to ensure that the centrifugal impeller will not be eccentric during rotation.

[0055] In one embodiment, the body 1 is further provided with an oil-throwing hole 11, which is located near the first air hole 2.

[0056] like Figure 2 As shown, the oil slinger hole 11 is located between the external spline 6 and the external thread 8, and is connected to the shaft hole 101. It is an annular hole or multiple holes are provided at intervals.

[0057] The main function of the oil slinger hole 11 is to ensure that there is no oil accumulation in the shaft hole 101. During the rotation of the centrifugal impeller, the lubricating oil in the shaft hole 101 is thrown out through the oil slinger hole 11 due to the centrifugal force.

[0058] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A centrifugal impeller, characterized in that, include: The body (1) includes a shaft hole (101) and a plurality of blades (102) distributed circumferentially along the shaft hole (101). The first air hole (2) and the second air hole (3) are respectively arranged on both sides of the blade (102) along the axial direction of the body (1), and both are connected to the shaft hole (101) to form a gas channel; The first sealing structure (4) is provided on the body (1) and is provided corresponding to the first air hole (2) so that high-pressure gas flows out from the first sealing structure (4).

2. The centrifugal impeller according to claim 1, characterized in that, It also includes a second sealing structure (5) disposed on the body (1), and along the axial direction of the body (1), the second vent (3) is located between the blade (102) and the second sealing structure (5).

3. The centrifugal impeller according to claim 2, characterized in that, Both the first sealing structure (4) and the second sealing structure (5) include two sets of helical teeth with opposite inclination directions along the axial direction of the body (1), and the gas flow direction is opposite to the inclination direction of the helical teeth.

4. The centrifugal impeller according to claim 3, characterized in that, The angle of the helical tooth is 15°-20°, and the angle between the helical tooth and the axial direction of the body (1) is 45°-60°.

5. The centrifugal impeller according to claim 3, characterized in that, The first vent (2) is located between the two sets of oblique teeth of the first sealing structure (4).

6. The centrifugal impeller according to any one of claims 1 to 5, characterized in that, The blade (102) includes a first blade (1021) and a second blade (1022) arranged circumferentially, and along the axial direction of the body (1), the length of the first blade (1021) is 50%-70% of the length of the second blade (1022).

7. The centrifugal impeller according to claim 6, characterized in that, The ratio of the number of the first blade (1021) to the number of the second blade (1022) is 1:

1.

8. The centrifugal impeller according to claim 6, characterized in that, Along the axial direction of the body (1), an external spline (6) and an internal spline (7) are respectively provided on both sides of the blade (102). The external spline (6) is located near the first air hole (2) and is suitable for spline connection with the drive shaft. The internal spline (7) is located near the second air hole (3) and is suitable for connection with the turbine disk.

9. The centrifugal impeller according to claim 8, characterized in that, Along the axial direction of the body (1), a shaft positioning surface and a spline positioning surface (10) are respectively provided in the shaft hole (101). The shaft positioning surface (9) is located on the side close to the outer spline (6), and the spline positioning surface (10) is located on the side close to the inner spline (7).

10. The centrifugal impeller according to any one of claims 1 to 5, characterized in that, The main body (1) is also provided with an oil-throwing hole (11), which is located near the first air hole (2).

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