A single stage compressor rotor blade with double type multi-channel vent holes to reduce noise

Abstract

The present application aims to provide a single-stage compressor rotor blade with double-type multi-channel ventilation holes to reduce noise, comprising a blade tip, a blade root, a leading edge, a trailing edge, a suction surface, a pressure surface, an A-type ventilation hole penetrating through the blade tip and the trailing edge and a B-type ventilation hole penetrating through the middle position of the pressure surface and the trailing edge are arranged inside the blade body, the inlet of the A-type ventilation hole is located at the blade tip, the outlet is located at the trailing edge, and the inlet is a straight line segment perpendicular to the blade tip with a length of D, the inlet of the B-type ventilation hole is located at the middle position of the pressure surface, and the outlet is located at the trailing edge. On the one hand, the double-type ventilation holes can reduce the vortex noise formed by the tip clearance leakage vortex and the trailing edge shedding vortex. On the other hand, reducing the size of the blade trailing edge shedding vortex can also reduce the interference between the rotor blade and the static blade, thereby reducing the single-frequency discrete noise of the compressor. Moreover, the double-type multi-channel ventilation hole structure reduces the difficulty of opening a single A-type ventilation hole.

Description

Technical Field

[0001] The present invention relates to a blade, specifically a compressor rotor blade. Background Technology

[0002] As is well known, noise is a significant source of environmental pollution in modern industrial society, with aerodynamic noise accounting for a considerable proportion. The primary source of aerodynamic noise is the aircraft propulsion system. With the rapid increase in the number and widespread use of civil aircraft, aviation noise has increasingly attracted global attention. The Federal Aviation Administration's regulations in the United States and Annex No. 1 of the International Civil Aviation Convention signify that noise has become a crucial indicator for evaluating aircraft airworthiness. Therefore, developing low-noise aircraft propulsion systems has become an urgent engineering challenge.

[0003] The engines used in modern aircraft are highly complex noise systems, with four main noise sources: compressor noise, combustion noise, turbine noise, and jet noise. Among these, the compressor noise and jet noise are the primary noise sources of the engine.

[0004] Compressor noise includes single-frequency discrete noise and broadband eddy noise at the blade passage frequency. Single-frequency discrete noise is caused by the mutual interference between the rotor and stator during compressor operation: (1) interference between the rotor blade potential flow field and the stator; (2) interference between the stator blade potential flow field and the rotor; (3) interference between the stator blade cutting the rotor blade wake; (4) interference between the rotor blade cutting the stator blade wake. Broadband eddy noise mainly includes: (1) separation eddy noise formed by the separation of turbulent boundary layer at the blade suction surface; (2) noise generated by leakage eddies at the blade tip; (3) noise formed by eddies formed by the shedding of rotor blade trailing edges.

[0005] Among them, the generation of single-frequency discrete noise and broadband eddy current noise are closely related to the generation of trailing edge vortices. For eddy current noise, trailing edge vortices occupy a dominant position in the overall eddy current noise, while for single-frequency discrete noise, the increase of trailing edge vortices will lead to more severe interference between the rotor and the stator.

[0006] Current compressor noise reduction methods mainly include using serrated blade trailing edges and multi-curvature blade surfaces to disrupt trailing edge vortices, thereby achieving the purpose of compressor noise reduction. Summary of the Invention

[0007] The purpose of this invention is to provide a single-stage compressor rotor blade with dual-type multi-channel vent holes for noise reduction.

[0008] The objective of this invention is achieved as follows:

[0009] This invention discloses a single-stage compressor rotor blade with dual-type multi-channel vent holes for noise reduction. The blade comprises a blade tip, blade root, leading edge, trailing edge, suction surface, and pressure surface. The blade body contains an A-type vent hole connecting the blade tip and trailing edge, and a B-type vent hole connecting the middle of the pressure surface and the trailing edge. The inlet of the A-type vent hole is located at the blade tip, and the outlet is located at the trailing edge. The inlet is a straight line segment perpendicular to the blade tip and of length D. The inlet of the B-type vent hole is located at the middle of the pressure surface, and the outlet is located at the trailing edge.

[0010] The present invention may also include:

[0011] 1. The inlet position of the type A vent at the blade tip is in the half section near the trailing edge. The inlet area of ​​the type A vent at the blade tip accounts for 0.5%-0.7% of the blade tip area, and the outlet area at the trailing edge accounts for 1%-1.2% of the trailing edge area.

[0012] 2. The diameter d of type A and type B ventilation holes is 1.5%-2% of the leaf height h. The spacing between each ventilation hole is evenly distributed at the leaf tip and at the trailing edge. The distance between two adjacent ventilation holes at the trailing edge is D3. The distance between the type B ventilation hole closest to the leaf root and the leaf root is D1. The distance between the type A ventilation hole closest to the leaf tip and the leaf tip is D2. D1 and D2 are equal and are 4%-8% of the leaf height h. D3 is 8%-12% of the leaf height h.

[0013] 3. The axis of the type A vent is a spatial curve distributed on the mid-curved surface, and the projection of these spatial curves on the projection surface is an arc with a central angle of 45°.

[0014] 4. The angle α between the inlet of the type B vent and the pressure surface can be taken as 30°. The axis of the type B vent is distributed in a plane parallel to the blade root.

[0015] 5. The spacing between adjacent A-type vents is L2. The distance between the first A-type vent on the blade tip and the trailing edge is L1. The last vent is located at the midpoint of the centerline of the blade tip. L1 is 3%-5% of the centerline length, and L2 is 1 / 15-1 / 10 of the centerline length.

[0016] 6. The intersection of the mid-curve at the blade tip and the trailing edge is the first point, and the intersection of the mid-curve at the blade root and the trailing edge is the second point. The straight line connecting the first and second points is called the first straight line. The chord of the blade tip profile is designated as the second straight line, and the chord of the blade root profile is designated as the third straight line. The plane formed by the first, second, and third straight lines is the projection plane. A2 is the projection of the axis A1 of the type A vent onto the projection plane. A coordinate system is established on the projection plane, with the origin O located on the first straight line and a distance D from the blade tip. D is the length of the straight line segment perpendicular to the blade tip at the inlet of the type A vent. The straight line passing through the origin O and coinciding with the first straight line is designated as the Y-axis. The straight line passing through the origin O and perpendicular to the Y-axis in the projection plane is designated as the X-axis. The straight line passing through the origin O and perpendicular to the XOY plane is designated as the Z-axis, with the positive direction of the Z-axis pointing towards the suction surface of the blade. The projection line A2 of the type A1 axis onto the projection plane is represented by the following equation:

[0017]

[0018] The mid-surface F1 is represented by the following equation:

[0019]

[0020] The axis of the type A vent can be represented by the following equation:

[0021]

[0022] In the above formula, i represents the distance from the axis of the i-th type A vent at the blade tip; b is the chord length, and d1 is the distance between the point on the corresponding arc at b / 2 and the chord.

[0023] 7. Curve B2 is the projection of the B1 type vent axis onto the blade root plane. The intersection of curve B2 and the pressure surface is set as the origin O. The straight line connecting the start and end points of curve B2 is set as the X-axis. The straight line in the blade root plane passing through the origin O and perpendicular to the X-axis is set as the Y-axis. The straight line passing through the origin O and perpendicular to the XOY plane is set as the Z-axis, with the positive direction of the Z-axis pointing towards the blade tip. Let the distance between the start and end points of projection line B2 be L, and the distance between the point on projection line B2 at L / 2 and the X-axis be d2. Then, the projection B2 of the B-type vent axis onto the blade root plane is represented by the following equation:

[0024]

[0025] The equation of the plane containing the axis of the i-th type B vent at the leaf root is as follows:

[0026] z = D1 + (i-1)D3

[0027] The axis of the type B vent is represented by the following equation:

[0028]

[0029] In the above formula, i represents the distance from the axis of the i-th type B vent at the leaf root.

[0030] The advantages of this invention are as follows: First, in the vortex noise of a single-stage compressor, tip clearance leakage vortices account for a considerable proportion. Tip clearance leakage vortices occur because the static pressure on the blade pressure surface is greater than the static pressure on the blade suction surface during blade operation. Furthermore, due to centrifugal force, gas from the blade pressure surface flows through the gap between the blade tip and the outer casing to the blade suction surface, forming vortices at the tip clearance and thus generating significant vortex noise. In addition, according to boundary layer theory, when airflow passes over the blade surface, vortex shedding occurs after the boundary layer develops to a certain extent. This shedding often reaches a very severe stage at the blade trailing edge, forming numerous shedding vortices. In compressor vortex noise, the noise caused by blade trailing edge shedding vortices plays a major role. The feature of this invention is the provision of a series of A-type vent holes penetrating the blade tip and trailing edge, and B-type vent holes penetrating the middle of the pressure surface and the trailing edge inside the rotor blade. Therefore, when part of the airflow flows into the dual-type vent from the middle position between the blade tip clearance and the pressure surface, and then exits from the trailing edge of the blade, the leakage vortex at the blade tip clearance is reduced to the greatest extent, and the large-sized shedding vortex located near the trailing edge is blown into a small-sized vortex, thereby significantly reducing the vortex noise of the single-stage compressor.

[0031] Secondly, in the single-frequency discrete noise of the compressor, whether it is the discrete noise generated by the interference between the blade potential flow field and another blade, or the noise generated by the viscous wake of one blade cutting another, the size of the trailing edge shedding vortex has a significant impact on these single-frequency noises. The feature of this invention is that a series of A-type vent holes penetrating the blade tip and trailing edge, and B-type vent holes penetrating the middle of the pressure surface and the trailing edge are opened inside the compressor rotor blades. Gas flowing into the dual-type vent holes will be ejected from the trailing edge, thereby dispersing the trailing edge shedding vortex. After the size of the trailing edge shedding vortex is reduced, the noise generated when the stator blade cuts the rotor viscous wake will be reduced. Furthermore, the interference noise between the potential flow fields of the stator blade and the rotor blade will also decrease.

[0032] Third, in addition to setting type A ventilation holes inside the blade, setting type B ventilation holes can greatly reduce the difficulty of opening holes from the entire blade tip to the trailing edge.

[0033] In summary, this invention reduces vortex noise generated by tip clearance leakage vortices and trailing edge shedding vortices through the dual-type venting structure. Furthermore, reducing the size of the trailing edge shedding vortex also reduces interference between the rotor blades and the stator blades, thereby lowering the compressor's single-frequency discrete noise. Additionally, the dual-type multi-channel venting structure simplifies the process of creating a single type A venting port. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the structure of the present invention installed in a compressor;

[0035] Figure 2 This is a schematic diagram of the structure of the present invention;

[0036] Figure 3 This is a schematic diagram of blade interference.

[0037] Figure 4 This is a schematic diagram of the blade tip structure;

[0038] Figure 5 This is a schematic diagram of the trailing edge structure;

[0039] Figure 6 This is a schematic diagram of the axis distribution;

[0040] Figure 7 This is a projection diagram of the A1 type axis;

[0041] Figure 8 This is a B1-type axis projection diagram. Detailed Implementation

[0042] The invention will now be described in more detail with reference to the accompanying drawings:

[0043] Combination Figure 1-8 This invention relates to a single-stage compressor rotor blade that reduces noise by incorporating dual-type multi-channel vents. For example... Figure 1 As shown, the overall structure of the present invention includes a compressor housing 1, rotor blades 2, stator blades 3, hub 4, blade tip clearance 5, and vent holes 6. Figure 2 and Figure 4 As shown, the blade includes a blade tip 9, a blade root 10, a leading edge 7, a trailing edge 8, a pressure surface 11, a suction surface 12, a type A vent, and a type B vent.

[0044] Combination Figures 1-3As the blades rotate with the hub, the static pressure on the pressure side of the blades is greater than that on the suction side due to the work done by the blades. Furthermore, the gas exhibits centrifugal force during rotation. Therefore, under the influence of the static pressure difference and centrifugal force, the gas flows from the pressure side through the blade tip gap to the suction side, forming vortices at the blade tip gap and generating considerable vortex noise. Moreover, because the rotor blades continuously do work on the airflow as it flows from the leading edge to the trailing edge, the static pressure difference between the pressure and suction sides is even greater near the trailing edge, and the tip gap leakage vortex near the trailing edge constitutes the majority of the total tip gap leakage vortex. In addition, according to boundary layer theory, the airflow forms a relatively strong shedding vortex at the blade trailing edge, and the noise generated by the trailing edge shedding vortex accounts for a major portion of the total aerodynamic noise. The feature of this invention is the creation of a series of A-type vents penetrating from the blade tip to the trailing edge and B-type vents penetrating the middle of the pressure side and the trailing edge inside the rotor blades. Figure 2 As shown, the airflow passing through the blade tip clearance flows directly into the type A vent, which significantly reduces the formation of leakage vortices in the blade tip clearance. On the other hand, the gas flowing into both the type A and type B vents is ejected from the blade trailing edge. This ejected airflow directly impacts the trailing edge shedding vortex, dispersing the large trailing edge shedding vortex into smaller vortices, which in turn greatly reduces the compressor's vortex noise.

[0045] like Figure 3 As shown, the compressor rotor blades interfere with the stator blades during rotation, resulting in discrete noise at a single frequency. The interference between the rotor and the stator includes: (1) interference between the rotor blade potential flow field and the stator; (2) interference between the stator blade potential flow field and the rotor; (3) interference between the stator blade cutting the rotor blade wake; and (4) interference between the rotor blade cutting the stator blade wake. The feature of this invention is that a series of A-type vent holes penetrating the tip and trailing edge and B-type vent holes penetrating the middle position of the pressure surface and the trailing edge are provided inside the rotor blades. One of the functions of the vent holes is to disperse the large-sized shedding vortices at the trailing edge into smaller vortices. Reducing the size of the trailing edge shedding vortex can reduce the single-frequency noise generated by the interference between the potential flow fields of the stator and rotor blades. On the other hand, the reduction of the vortex amount in the viscous wake of the rotor blades will also reduce the single-frequency noise generated by the stator cutting the rotor blade wake.

[0046] like Figure 4 As shown, the blade tip structure includes the center arc line 13, the intersection point 14 of the center arc line and the leading edge of the blade, the intersection point 15 of the center arc line and the trailing edge of the blade, and a chord 16. The center arc line is the line connecting the centers of the inscribed circles of the blade, often simply called the centerline. The chord is the straight line connecting the intersection points of the center arc line and the leading and trailing edges of the blade; the length of the chord is called the chord length, denoted by the letter b. The distance between the point on the center arc line at b / 2 and the chord is set as d1. The surface that runs through the center arc line at the blade tip and the center arc line at the blade root is called the center surface. Figure 6 In this context, F1 represents the mid-curved surface.

[0047] Depend on Figure 4 It can be seen that the A-type vents are distributed on the blade tip in the half near the trailing edge, and are equidistantly distributed along the centerline. The distance between adjacent vents is L2, the distance between the first vent and the trailing edge is L1, and the last vent is located at the midpoint of the mid-arc line at the blade tip. L1 can be set to 3%-5% of the centerline length, and L2 can be set to 1 / 15-1 / 10 of the centerline length.

[0048] Depend on Figure 6 and Figure 8 It can be seen that the axis of the B-type vent is located in a plane parallel to the blade root. For example, the axis of the B-type vent represented by serial number ⑥ is located on plane F2. The angle α between the inlet of the B-type vent and the pressure surface can be taken as 30°. The outlet of the B-type vent is perpendicular to the trailing edge of the blade.

[0049] Depend on Figure 5 It can be seen that type A and type B ventilation holes are equidistantly distributed on the trailing edge, with the distance between two adjacent ventilation holes being D3. The distance between the type B ventilation hole closest to the leaf root and the leaf root is D1, and the distance between the type A ventilation hole closest to the leaf tip and the leaf tip is D2. D1 and D2 can be taken as equal values, both of which can be taken as 4%-8% of the leaf height h, and D3 can be taken as 8%-12% of the leaf height h.

[0050] Depend on Figure 6 It can be seen that the mid-curved surface F1 is a curved surface composed of the arc lines in the cross-sectional profiles between the blade tip and the blade root, and F2 is a plane parallel to the blade root. The axis A1 of the type A vent is located on the mid-curved surface F1, and the axis B1 of the type B vent is located on each plane parallel to the blade root.

[0051] The spatial curves numbered ①-⑤ are used to represent the axis of the type A vent, and the curves numbered ⑥- The spatial curve used to represent the axis of the B-type vent is shown. The position and shape of the vent axis at different locations of the same model can be obtained by taking different variable values ​​from the same equation.

[0052] The perforations at the leaf tip are located in the half-section near the trailing edge. The perforation area at the leaf tip accounts for 0.5%-0.7% of the leaf tip area, while the perforation area at the trailing edge accounts for 1%-1.2% of the trailing edge area.

[0053] The diameter d of the ventilation holes can be taken as 1.5%-2% of the leaf height h. The spacing between each ventilation hole is evenly distributed at the leaf tip and at the trailing edge.

[0054] The type A vent is a straight line segment of length D perpendicular to the blade tip at the inlet, and perpendicular to the blade trailing edge at the outlet. The entire vent axis is a spatial curve distributed on the mid-curve surface. Furthermore, the projections of these spatial curves onto the projection plane are all arcs with a central angle of 45°.

[0055] The angle α between the inlet of the B-type vent and the pressure surface can be taken as 30°, the outlet is perpendicular to the trailing edge of the blade, and the entire vent axis is distributed in a plane parallel to the blade root.

[0056] like Figure 7 As shown, let point 15.1 be the intersection of the mid-curve at the blade tip and the trailing edge, and point 15.2 be the intersection of the mid-curve at the blade root and the trailing edge. The straight line connecting points 15.1 and 15.2 is called line 17. The chord of the blade tip profile is defined as line 16.1, and the chord of the blade root profile is defined as line 16.2. The plane formed by lines 16.1, 16.2, and 17 is the projection plane, and A2 is the projection of the A1 type axis onto the projection plane. Establish a coordinate system on the projection plane, with the origin O located on line 17 and a distance D from the blade tip, where D is the length of the straight line segment perpendicular to the blade tip at the inlet of the A-type vent. The straight line passing through the origin O and coinciding with line 17 is defined as the Y-axis; the straight line passing through the origin O and perpendicular to the Y-axis in the projection plane is defined as the X-axis; and the straight line passing through the origin O and perpendicular to the XOY plane is defined as the Z-axis, with the positive direction of the Z-axis pointing towards the blade suction surface. The projection line A2 of the A1 type axis onto the projection plane can be represented by the following equation:

[0057]

[0058] On the other hand, the mid-curved surface F1 can be represented by the following equation:

[0059]

[0060] Therefore, the axis of the type A vent can be represented by the following equation:

[0061]

[0062] In the above formula, i represents the distance from the axis of the i-th type A vent at the blade tip; D2, D3, and D are... Figure 5 and Figure 7 The structural parameters on; d1 and b are Figure 4 The structural parameters are: b is the chord length, and d1 is the distance between the point on the middle arc corresponding to b / 2 and the chord.

[0063] like Figure 8As shown, curve B2 is the projection of the B1 type axis onto the blade root plane. The intersection of curve B2 and the pressure surface is set as the origin O; the straight line connecting the start and end points of curve B2 is set as the X-axis; the straight line in the blade root plane passing through the origin O and perpendicular to the X-axis is set as the Y-axis; and the straight line passing through the origin O and perpendicular to the XOY plane is set as the Z-axis, with the positive direction of the Z-axis pointing towards the blade tip. Let the distance between the start and end points of projection line B2 be L, and the distance between the point on projection line B2 at L / 2 and the X-axis be d2. Then, the projection B2 of the B-type vent axis onto the blade root plane can be represented by the following equation:

[0064]

[0065] On the other hand, the equation of the plane containing the axis of the i-th type B vent at the leaf root is as follows:

[0066] z = D1 + (i-1)D3

[0067] Therefore, the axis of the type B vent can be represented by the following equation:

[0068]

[0069] In the above formula, i represents the distance from the axis of the i-th type B vent at the leaf root; D1 and D3 are... Figure 5 The structural parameters on; d2 and L are Figure 8 The structural parameters on.

Claims

1. A single-stage compressor rotor blade with dual-type multi-channel vent holes for noise reduction, characterized in that: Including leaves The blade body has an A-type vent hole that connects the blade tip and the trailing edge, and a B-type vent hole that connects the middle of the pressure surface and the trailing edge. The inlet of the A-type vent hole is located at the blade tip and the outlet is located at the trailing edge. The inlet is a straight line segment with a length of D perpendicular to the blade tip. The inlet of the B-type vent hole is located at the middle of the pressure surface and the outlet is located at the trailing edge. The first point is the intersection of the mid-curve at the blade tip and the trailing edge, and the second point is the intersection of the mid-curve at the blade root and the trailing edge. The straight line connecting the first and second points is called the first straight line. The chord of the blade tip profile is called the second straight line, and the chord of the blade root profile is called the third straight line. The plane formed by the first, second, and third straight lines is the projection plane. A2 is the projection of the axis A1 of the type A vent onto the projection plane. A coordinate system is established on the projection plane, with the origin O located on the first straight line and a distance D from the blade tip. D is the length of the straight line segment perpendicular to the blade tip at the inlet of the type A vent. The straight line passing through the origin O and coinciding with the first straight line is designated as the Y-axis. The straight line passing through the origin O and perpendicular to the Y-axis in the projection plane is designated as the X-axis. The straight line passing through the origin O and perpendicular to the XOY plane is designated as the Z-axis, with the positive direction of the Z-axis pointing towards the suction surface of the blade. The projection line A2 of the type A1 axis onto the projection plane is represented by the following equation: The mid-surface F1 is represented by the following equation: The axis of the type A vent can be represented by the following equation: In the above formula, i represents the distance from the axis of the i-th type A vent at the blade tip; b is the chord length; d1 is the distance between the point on the corresponding mid-arc line at b / 2 and the chord; D3 is the distance between two adjacent vents on the trailing edge; and D2 is the distance between the type A vent closest to the blade tip and the blade tip.

2. A single-stage compressor rotor blade with dual-type multi-channel vent holes for noise reduction as described in claim 1, characterized in that: in The inlet of the A-type vent at the blade tip is located in the half-section near the trailing edge. The inlet area of ​​the A-type vent at the blade tip accounts for 0.5%-0.7% of the blade tip area, while the outlet area at the trailing edge accounts for 1%-1.2% of the trailing edge area.

3. A single-stage compressor rotor blade with dual-type multi-channel vent holes for noise reduction as described in claim 1, characterized in that: The diameter d of type A and type B ventilation holes is 1.5%-2% of the leaf height h. The spacing between each ventilation hole is evenly distributed at the leaf tip and at the trailing edge. The distance between the type B ventilation hole closest to the leaf root and the leaf root is D1. D1 and D2 are equal and are 4%-8% of the leaf height h. D3 is 8%-12% of the leaf height h.

4. A single-stage compressor rotor blade with dual-type multi-channel vent holes for noise reduction as described in claim 1, characterized in that: The A-type vent axis is a spatial curve distributed on the mid-curved surface, and the projection of these spatial curves on the projection surface is an arc with a central angle of 45°.

5. A single-stage compressor rotor blade with dual-type multi-channel vent holes for noise reduction according to claim 1, characterized in that: The angle α between the inlet of the type B vent and the pressure surface can be taken as 30°, and the axis of the type B vent is distributed in a plane parallel to the blade root.

6. A single-stage compressor rotor blade with dual-type multi-channel vent holes for noise reduction according to claim 1, characterized in that: The spacing between adjacent A-type vents is L2. The distance between the first A-type vent on the blade tip and the trailing edge is L1. The last vent is located at the midpoint of the centerline of the blade tip. L1 is 3%-5% of the centerline length, and L2 is 1 / 15-1 / 10 of the centerline length.

7. A single-stage compressor rotor blade with dual-type multi-channel vent holes for noise reduction according to claim 1, characterized in that: Curve B2 To represent the projection of the B1 type vent axis onto the blade root plane, the intersection of curve B2 and the pressure surface is set as the origin O of the coordinate system; the straight line connecting the start and end points of curve B2 is set as the X-axis; the straight line passing through the origin O and perpendicular to the X-axis in the blade root plane is set as the Y-axis; the straight line passing through the origin O and perpendicular to the XOY plane is set as the Z-axis, with the positive direction of the Z-axis pointing towards the blade tip. Let the distance between the start and end points of projection line B2 be L, and the distance between the point on projection line B2 at L / 2 and the X-axis be d2. Then, the projection B2 of the B-type vent axis onto the blade root plane is represented by the following equation: The equation of the plane containing the axis of the i-th type B vent at the leaf root is as follows: The axis of the type B vent is represented by the following equation: In the above formula, i represents the distance from the axis of the i-th type B vent at the leaf root.

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