An air extraction device and method for a last-stage axial-flow compressor to adjust the axial force of the rotor

Abstract

The present invention discloses an air extraction device and method for regulating the axial force of a rotor in a last-stage axial-flow compressor. The device includes a certain gap formed between a first labyrinth seal and a honeycomb wear-resistant layer. A swirl enhancing deflector is arranged at the outlet of the first labyrinth seal. The swirl enhancing deflector and the inner ring of the combustion chamber form a second chamber. A third chamber is formed between the swirl enhancing deflector and a pull rod, and a P1 position point is arranged at the outlet of the third chamber. When the engine runs from cold state to hot state, the gap between the first labyrinth seal and the honeycomb wear-resistant layer gradually decreases as the rotation speed increases and the tip of the first labyrinth seal scrapes out a groove on the honeycomb wear-resistant layer. The air extraction through the groove can enhance the throttling and pressure-reducing capacity of the first labyrinth seal and reduce the pressure at the P2 position point at the outlet of the first labyrinth seal. By controlling the distance between the swirl enhancing deflector and the pull rod, the radial velocity of the radially inward flowing air extraction in the third chamber is increased, and the radial pressure drop from the P2 position at the outlet of the first labyrinth seal to the P1 position at the outlet of the third chamber is increased. The gas is discharged from the P2 position through the P1 position to the P3 position.

Description

Technical Field

[0001] The present invention relates to the technical field of compressors, and particularly to an air extraction device and method for a last-stage axial compressor for adjusting the axial force of a rotor. Background Technique

[0002] In a turbofan engine with a full axial compressor structure in the large thrust level range (5000 kgf to 10000 kgf), there is generally a problem of excessive forward axial force of the high-pressure rotor. Therefore, in the last stage of the axial compressor, air is usually bled (for cooling of rear-end components or generating thrust in the bypass) to reduce the cavity pressure of the last-stage compressor disk cavity, thereby reducing the forward axial force of the high-pressure rotor. However, due to the high absolute pressure in the last-stage compressor disk cavity, a large amount of air needs to be bled to reduce the cavity pressure to an ideal level, which has an adverse impact on the overall performance of the engine.

[0003] The present invention proposes a large-pressure-drop air extraction design technology applicable to the rear disk cavity of the last-stage axial compressor of an engine. Through a multi-stage stepped oblique labyrinth with a honeycomb belt wear groove and a radial swirl guide vane scheme, under the condition of keeping the air extraction amount unchanged, the rotational side pressure of the disk cavity can be greatly reduced, thereby reducing the forward axial force of the high-pressure rotor and achieving the purpose of reducing the axial force of the high-pressure rotor of the whole engine. Summary of the Invention

[0004] The purpose of the present invention is to provide an air extraction device and method for a last-stage axial compressor for adjusting the axial force of a rotor, so as to solve the problems raised in the above background technique.

[0005] To achieve the above purpose, the present invention provides the following technical solutions:

[0006] An air extraction device for a last-stage axial compressor for adjusting the axial force of a rotor, the device includes a first labyrinth, a honeycomb wear-resistant layer, a swirl guide vane, a pull rod, and an inner ring of a combustion chamber. Among them,

[0007] A certain gap is formed between the first labyrinth and the honeycomb wear-resistant layer; a swirl guide vane is arranged at the outlet of the first labyrinth, and a second chamber is formed between the swirl guide vane and the inner ring of the combustion chamber; a third chamber is formed between the swirl guide vane and the pull rod, and a P1 position point is arranged at the outlet of the third chamber.

[0008] Preferably, the device further includes a last-stage compressor disk, a labyrinth disk, a second labyrinth, a first labyrinth bushing, a second labyrinth bushing, a first bolt, a second bolt, and a third bolt. Among them,

[0009] A first chamber is formed between the last-stage compressor disk and the labyrinth disk; an air extraction port is arranged between the top end of the last-stage compressor disk and the first labyrinth bushing, and a honeycomb wear-resistant layer is arranged on the bottom surface of the first labyrinth bushing;

[0010] The last-stage compressor disk is provided with an extension rod which is fixedly connected to the labyrinth disk by a second bolt. The other side of the labyrinth disk is connected to the pull rod. The end of the labyrinth disk is provided with a first labyrinth. The outlet of the first labyrinth is provided with a P2 position point;

[0011] The second labyrinth bushing is fixed to the inner side of the end of the combustion chamber by a third bolt. The second labyrinth is located inside the tail of the pull rod and below the second labyrinth bushing;

[0012] The swirl guide vane is fixedly connected to the first labyrinth bushing and the inner ring of the combustion chamber by a first bolt. The upper end of the inner ring of the combustion chamber is provided with a bleed point at the P3 position.

[0013] A certain gap is formed between the first labyrinth and the honeycomb wear-resistant layer; a swirl guide vane is arranged at the outlet of the first labyrinth. The swirl guide vane and the inner ring of the combustion chamber form a second chamber; a chamber is formed between the swirl guide vane and the pull rod. The outlet of the chamber is provided with a P1 position point.

[0014] Preferably, the device further includes a last-stage compressor disk, a labyrinth disk, a second labyrinth, a first labyrinth bushing, a second labyrinth bushing, and bolts, wherein,

[0015] An air extraction port is arranged between the top end of the last-stage compressor disk and the first labyrinth bushing. The bottom surface of the first labyrinth bushing is provided with a honeycomb wear-resistant layer;

[0016] The last-stage compressor disk is provided with an extension rod which is fixedly connected to the labyrinth disk by a second bolt. The other side of the labyrinth disk is connected to the pull rod. The end of the labyrinth disk is provided with a first labyrinth. The outlet of the first labyrinth is provided with a P2 position point;

[0017] The second labyrinth bushing is fixed to the inner side of the end of the combustion chamber by a third bolt. The second labyrinth is located inside the tail of the pull rod and below the second labyrinth bushing;

[0018] The swirl guide vane is fixedly connected to the first labyrinth bushing and the inner ring of the combustion chamber by a first bolt. The upper end of the inner ring of the combustion chamber is provided with a bleed point at the P3 position.

[0019] Preferably, the size of the gap is used to satisfy that the first labyrinth scrapes out a groove around the honeycomb wear-resistant layer. The length of the worn groove is 1-2 mm and the depth is 0.2-0.4 mm.

[0020] Preferably, the distance of the gap is obtained by calculating the thermal expansion deformation amount and rotational centrifugal deformation amount of the labyrinth, the radial clearance of the bearing, the radial runout of the labyrinth tooth tip, and the thermal expansion deformation amount of the honeycomb wear-resistant layer. Specifically, the gap calculation formula is as follows:

[0021] Δr = ΔLs - ΔLr

[0022] In the formula, Δr represents the radial clearance at the design point, ΔLs represents the radial elongation of the stator component, and Δ

[0023] Lr represents the radial elongation of the rotor component.

[0024] Preferably, the groove is used to enhance the throttling and pressure reduction ability of the first labyrinth seal, and reduce the pressure at the P2 position at the outlet of the first labyrinth seal.

[0025] Preferably, the first labyrinth seal is a multi-step inclined labyrinth seal, where the number of steps is 3 to 6, and the step height is 1 / 3 to 2 / 3 of the tooth height;

[0026] The honeycomb wear-resistant layer is located at the bottom of the first labyrinth seal bushing and above the first labyrinth seal; the first labyrinth seal bushing, the honeycomb wear-resistant layer cooperate with the multi-steps of the first labyrinth seal.

[0027] Preferably, the tie rod is set to be strip-shaped;

[0028] Control the distance between the swirl guide vane and the tie rod to be 1 to 2 mm, which is used to increase the swirl coefficient of the third chamber and improve the radial pressure drop from the radial internal flow bleed air at P2 to P1.

[0029] Preferably, the second labyrinth seal bushing is L-shaped, one end of the L-shape is fixed to the clamping block at the tail end of the combustion chamber inner ring through the third bolt, and the other end of the L-shape is parallelly mated with the tooth tip of the second labyrinth seal.

[0030] Preferably, the area of the third chamber is smaller than that of the second chamber;

[0031] The swirl coefficient of the third chamber is higher than that of the second chamber during the air bleeding process;

[0032] During the air bleeding process of the second chamber, the internal static pressure distribution is uniform, and the radial pressure difference < 1%.

[0033] Preferably, the tie rod, the combustion chamber inner ring, the labyrinth seal disc and the last-stage compressor disc are integrally formed parts.

[0034] Preferably, the last-stage compressor disc, the labyrinth seal disc, the tie rod, the first labyrinth seal, and the second labyrinth seal are rotating parts;

[0035] The first labyrinth seal bushing, the honeycomb wear-resistant layer, the combustion chamber inner ring, the swirl guide vane, and the second labyrinth seal bushing are stator parts.

[0036] A method for bleeding air from the last-stage axial compressor for adjusting the axial force of the rotor, characterized in that the method includes:

[0037] When the engine runs from cold to hot, the clearance between the first labyrinth seal and the honeycomb wear-resistant layer gradually decreases as the rotational speed increases. The tip of the first labyrinth seal scrapes out a groove on the honeycomb wear-resistant layer. The bleeding air passing through the groove can enhance the throttling and pressure-reducing ability of the first labyrinth seal and reduce the pressure at the P2 position at the outlet of the first labyrinth seal.

[0038] By controlling the distance between the swirl guide vane and the pull rod, the radial velocity of the radially inward bleeding air in the third chamber is increased, and the radial pressure drop from the P2 position at the outlet of the first labyrinth seal to the P1 position at the outlet of the third chamber is increased. The gas is discharged from the P2 position through the P1 position to the P3 position.

[0039] Preferably, the method further includes

[0040] The swirl guide vane and the inner ring of the combustion chamber form a second chamber with a low swirl coefficient and no radial pressure difference. The pressure at the high-radius position P3 of the gas outlet inside the second chamber is the same as the pressure at the low-radius position P1.

[0041] Preferably, the first labyrinth seal is a multi-step inclined labyrinth seal, where the number of steps is 3 to 6, and the step height is about 1 / 3 to 2 / 3 of the tooth height.

[0042] The honeycomb wear-resistant layer is located at the bottom of the first labyrinth seal bushing and above the first labyrinth seal. The first labyrinth seal bushing, the honeycomb wear-resistant layer cooperate with the multi-steps of the first labyrinth seal.

[0043] The groove scraped out by the tip of the first labyrinth seal on the honeycomb wear-resistant layer is 1 to 2 mm long and 0.2 to 0.4 mm deep.

[0044] The clearance is obtained by calculating the thermal expansion deformation amount and rotational centrifugal deformation amount of the first labyrinth seal, the radial clearance of the bearing, and the radial runout amount of the tip of the first labyrinth seal, and the thermal expansion deformation amount of the honeycomb wear-resistant layer. Specifically,

[0045] The clearance calculation formula is as follows:

[0046] Δr = ΔLs - ΔLr

[0047] In the formula, Δr represents the radial clearance at the design point, ΔLs represents the radial elongation of the stator part, and ΔLr represents the radial elongation of the rotor part.

[0048] Preferably, the groove can enhance the throttling and pressure-reducing ability of the first labyrinth seal and reduce the pressure at the P2 position at the outlet of the first labyrinth seal.

[0049] Preferably, the distance between the swirl guide vane and the pull rod is controlled within 1 to 2 mm.

[0050] When the chamber pressure of the third chamber decreases, the axial force on the rotating side of the third chamber can be reduced, and the forward axial force of the high-pressure rotor during takeoff or high-power operation of the engine can be decreased.

[0051] Technical effects and advantages of the present invention:

[0052] 1. The first labyrinth seal (multi-step inclined labyrinth seal) with wear grooves on the honeycomb band and the first labyrinth seal bushing cooperating with the first labyrinth seal are provided with a honeycomb wear-resistant layer. The first labyrinth seal scrapes a groove on the honeycomb layer, greatly enhancing the throttling and pressure-reducing ability of the first labyrinth seal and reducing the pressure at the outlet P2 of the first labyrinth seal.

[0053] 2. By means of the rotation-enhancing guide vane, the acceleration effect of the Coriolis force of the radial inward flow in the disc chamber on the circumferential velocity of the air flow is enhanced, the swirl coefficient of the third chamber is increased, thereby increasing the radial pressure drop from the radial inward flow bleed air P2 to P1 and reducing the pressure at the P1 position.

[0054] 3. The static pressure distribution in the second chamber is uniform, there is no radial pressure difference, the pressure at the bleed position P3 is the same as that at P1, and it is the lowest pressure value in the second chamber. Bleeding air at the P3 position with the lowest pressure is beneficial to reducing the pressure in the second chamber under the condition that the bleed air volume is the same as that of the conventional technical solution.

[0055] 4. On the premise of ensuring the same bleed air volume, this solution can significantly reduce the chamber pressure of the third chamber (at the P2 position and the P1 position), which is beneficial to reducing the axial force on the rotating side of the third chamber, thereby reducing the forward axial force of the high-pressure rotor during takeoff and other high-power operations of the engine and being beneficial to ensuring the normal service life of the bearing.

[0056] Other features and advantages of the present invention will be described in the subsequent description, and part of them will be obvious from the description or understood by implementing the present invention. The objectives and other advantages of the present invention can be achieved and obtained through the structures pointed out in the description, the claims and the drawings. Brief Description of the Drawings

[0057] Figure 1 Schematic diagram of the air bleed device in the prior art;

[0058] Figure 2 Schematic diagram of the air bleed device of the present invention;

[0059] Figure 3 Partial enlarged view of the structure of the first labyrinth seal and the honeycomb wear-resistant layer of the present invention;

[0060] Figure 4 Flow line of the middle section of the first labyrinth seal in the embodiment of the present invention;

[0061] Figure 5 Flow line of the middle section of the first labyrinth seal with wear grooves on the honeycomb band in the embodiment of the present invention;

[0062] Figure 6 Schematic diagram of uneven deformation in the circumferential direction of the rotor part in the embodiment of the present invention;

[0063] Figure 7 Comparison of leakage coefficients in the embodiment of the present invention;

[0064] Figure 8 Conventional exhaust 1.2% scheme in the embodiment of the present invention;

[0065] Figure 9 Conventional exhaust 3% scheme in the embodiment of the present invention;

[0066] Figure 10 Swirl coefficient of the conventional exhaust 1.2% scheme in the embodiment of the present invention;

[0067] Figure 11 Exhaust 1.2% scheme of the present invention in the embodiment of the present invention;

[0068] Figure 12 Swirl coefficient of the exhaust 1.2% of the present invention scheme in the embodiment of the present invention.

[0069] In the figure: 1. First chamber; 2. Second chamber; 3. Third chamber; 4. First labyrinth; 5. Labyrinth disc; 6. First labyrinth bushing; 7. Swirl guide vane; 8. Combustion chamber inner ring; 9. First bolt; 10. Honeycomb wear-resistant layer; 11. Tie rod; 12. Last-stage compressor disc; 13. Second bolt; 14. Second labyrinth; 15. Second labyrinth bushing; 16. Third bolt. Detailed implementation manners

[0070] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0071] In the conventional technical solution, such as Figure 1As shown in the figure, the compressor includes a rotating part and a stator part. Among them, the rotating part includes: the last-stage compressor disk 12, the labyrinth disk 5, and the tie rod 11. Among them, the last-stage compressor disk 12, the labyrinth disk 5, and the tie rod 11 are fixedly connected by the second bolt 13. The end of the labyrinth disk 5 is provided with a first labyrinth 4, and the first labyrinth 4 contacts the first labyrinth bushing 6. A first chamber 1 is formed between the last-stage compressor disk 12 and the first labyrinth bushing 6. The bleed air in the first chamber 1 flows to the inner ring 8 of the combustion chamber through the connection between the first labyrinth 4 and the first labyrinth bushing 6. The stator part includes: the first labyrinth bushing 6, the inner ring 8 of the combustion chamber, and the second labyrinth bushing 15. Among them, the first labyrinth bushing 6 and the inner ring 8 of the combustion chamber are fixedly connected by the first bolt 9. A second chamber 2 is formed between the inner ring 8 of the combustion chamber and the tie rod 11. The tail of the tie rod 11 is provided with a second labyrinth 14, and the second labyrinth 14 contacts the second labyrinth bushing 15. The straight-through labyrinth has poor throttling effect, and the radius position of the labyrinth is relatively high. The bleed air still has a relatively high pressure P1 after passing through the straight-through labyrinth. At the same time, affected by the rotating pump effect, there is a significant radial pressure difference in the second chamber 2, specifically manifested as high static pressure at high radius and low static pressure at low radius. The P3 pressure in the second chamber 2 > P2 pressure > P1 pressure. When bleeding air from the P3 position at high radius in the second chamber 2, with a relatively high pressure level and a certain amount of bleed air, the reduction amplitude of the chamber pressure is limited. If the chamber pressure needs to be reduced to the target pressure, a large amount of air needs to be bled off, which has a great impact on the overall performance of the engine.

[0072] To solve the deficiencies of the prior art, the present invention discloses an air bleeding device and method for the last-stage axial compressor for adjusting the axial force of the rotor, as Figure 2 shown, the device includes a rotating part and a stator part. Among them, the rotating part includes the last-stage compressor disk 12, the labyrinth disk 5, the tie rod 11, the first labyrinth 4, and the second labyrinth 14; the stator part includes the first labyrinth bushing 6, the honeycomb wear-resistant layer 10, the inner ring 8 of the combustion chamber, the swirl guide vane 7, and the second labyrinth bushing 15;

[0073] The first labyrinth 4 is a multi-step inclined labyrinth. Among them, the number of steps is 3 to 6, and the step height is about 1 / 3 to 2 / 3 of the tooth height. The honeycomb wear-resistant layer 10 is located at the bottom of the first labyrinth bushing 6 and above the first labyrinth 4. The first labyrinth bushing 6, the honeycomb wear-resistant coating 10 cooperate with the multi-steps of the first labyrinth 4. A certain gap is formed between the first labyrinth 4 and the honeycomb wear-resistant layer 10. The gap can enable the first labyrinth 4 to scrape out a groove on the honeycomb wear-resistant layer 10. The length of the worn groove is about 1 to 2 mm, and the depth is about 0.2 to 0.4 mm. When the engine speed is increased, the deformation amount of the first labyrinth 4 is greater than that of the first bushing 6, and the first labyrinth 4 scrapes out a groove on the honeycomb wear-resistant layer 10.

[0074] The distance of the gap is obtained by calculating the thermal expansion deformation amount and rotational deformation amount of the first labyrinth tooth 4 during engine operation, the radial clearance of the bearing, the radial runout amount of the tip of the first labyrinth tooth 4, and the thermal expansion deformation amount of the honeycomb wear-resistant layer 10. Specifically, the gap calculation formula is as follows:

[0075] Δr = ΔLs - ΔLr

[0076] In the formula, Δr represents the radial clearance at the design point; ΔLs represents the radial elongation of the stator part, including thermal expansion deformation and internal pressure deformation, where the influence of internal pressure deformation is very small; ΔLr represents the radial elongation of the rotor part, including thermal expansion deformation and centrifugal deformation during the rotation of the rotor part. These two items are uniform in the circumferential direction. At the same time, the rotor part is also affected by the radial clearance of the bearing and the radial runout of the labyrinth tooth tip. The circumferential deformation of the rotor part is non-uniform. The circumferential non-uniform amount at a certain azimuth of the rotor is marked as δ, and the circumferential non-uniform deformation is as Figure 6 shown. Figure 6 This is a schematic diagram of the non-uniform deformation of the rotor part in the circumferential direction in the embodiment of the present invention. It can be seen from the figure that when the tip of the first labyrinth tooth 4 of the rotor part with circumferential non-uniform deformation scrapes into the honeycomb layer, a groove is ground out in a circle on the circumferential direction of the outer ring of the honeycomb. The circumferential non-uniform amount at a certain azimuth of the rotor is marked as δ.

[0077] The tip of the first labyrinth tooth 4 can scrape out a groove on the honeycomb wear-resistant layer 10. The length of the worn groove is about 1 - 2 mm, and the depth is about 0.2 - 0.4 mm. The groove can enhance the throttling and pressure-reducing ability of the first labyrinth tooth 4 and reduce the pressure at the P2 position point at the outlet of the first labyrinth tooth 4. In the prior art, the straight-through labyrinth tooth used does not produce a groove that can throttle and reduce pressure during the air extraction process, and the air still has a relatively high pressure P1 after passing through the straight-through labyrinth tooth.

[0078] The tie rod 11, the inner ring 8 of the combustion chamber, the labyrinth tooth disc 5, and the last-stage compressor disc 12 are integrally formed parts. An air extraction port is provided between the top of the last-stage compressor disc 12 and the first labyrinth tooth bushing 6. The last-stage compressor disc 12 is provided with an extension rod that is fixedly connected to the labyrinth tooth disc 5 through a second bolt 13. The other side of the labyrinth tooth disc 5 is fixedly connected to the tie rod 11. The labyrinth tooth disc 5 is set in a rod shape. The first labyrinth tooth 4 is provided at the top of the labyrinth tooth disc 5. A swirl guide vane 7 is provided at the outlet of the first labyrinth tooth 4. The swirl guide vane 7 is fixedly connected to the first labyrinth tooth bushing 6 and the inner ring 8 of the combustion chamber through bolts 9;

[0079] An air release P3 position point is provided at the upper end of the inner ring 8 of the combustion chamber. A clamping block is provided at the tail end of the inner ring 8 of the combustion chamber. One end of the L-shaped second labyrinth tooth bushing 15 is fixedly connected to the clamping block at the tail end of the inner ring 8 of the combustion chamber through a third bolt 16, and the other L-shaped end is arranged parallel and opposite to the tip of the second labyrinth tooth 14.

[0080] The second labyrinth 14 is located inside the tail of the pull rod 11 and below the second labyrinth bushing 15; the second labyrinth 14 cooperates with the second labyrinth bushing 15. The pull rod 11 is arranged in a long strip shape, and the distance between the swirl guide vane 7 and the pull rod 11 is controlled within 1-2 mm.

[0081] The last-stage compressor disk 12 and the labyrinth disk 6 form a first chamber 1, a third chamber 3 is formed between the swirl guide vane 7 and the pull rod 11, and a second chamber 2 is formed between the swirl guide vane 7 and the combustion chamber inner ring 8.

[0082] The swirl guide vane 7 is used to increase the swirl coefficient of the third chamber 3, increase the radial pressure drop of the radial internal flow bleed from P2 to P1, and ensure that the static pressure distribution in the second chamber 2 is uniform without a radial pressure difference.

[0083] A method for bleeding air from the last-stage axial compressor to adjust the axial force of the rotor is specifically as follows:

[0084] The engine bleed air enters the first chamber 1 from the bleed port between the top of the last-stage compressor disk 12 and the first labyrinth bushing 6. When running from cold to hot, the deformation amount of the first labyrinth 4 of the rotating part is greater than that of the first labyrinth bushing 6 of the stator part, the honeycomb wear-resistant layer 10, and the tip of the first labyrinth 4 scrapes out a groove around on the honeycomb wear-resistant layer 10. The length of the wear groove is 1-2.5 mm and the depth is 0.2-0.4 mm, which can greatly enhance the throttling and pressure-reducing ability of the first labyrinth 4, and the pressure at the outlet P1 position of the third chamber 3 formed between the swirl guide vane 7 and the pull rod 11 decreases; among them, the first labyrinth 4 is a multi-step inclined labyrinth, and the number of steps is 3-6, and the step height is about 1 / 3-2 / 3 of the tooth height;

[0085] The honeycomb wear-resistant layer 10 is located at the bottom of the first labyrinth bushing 6 and above the first labyrinth 4; the first labyrinth bushing 6, the honeycomb wear-resistant layer 10 cooperate with the multi-steps of the first labyrinth 4;

[0086] The groove scraped out by the tip of the first labyrinth 4 on the honeycomb wear-resistant layer 10 has a length of 1-2 mm and a depth of about 0.2-0.4 mm.

[0087] The gap is obtained by calculating the thermal expansion deformation amount and rotational deformation amount of the first labyrinth 4, the radial clearance of the bearing, the radial runout amount of the tip of the first labyrinth 4, and the thermal expansion deformation amount of the honeycomb wear-resistant layer 10. Specifically, the gap calculation formula is as follows:

[0088] Δr = ΔLs - ΔLr

[0089] In the formula, Δr represents the radial clearance at the design point; ΔLs represents the radial elongation of the stator components, including thermal expansion deformation and internal pressure deformation, where the influence of internal pressure deformation is very small; ΔLr represents the radial elongation of the rotor components, including thermal expansion deformation and centrifugal deformation during the rotation of the rotor components. These two items are uniform in the circumferential direction. At the same time, the rotor components are also affected by the radial clearance of the bearings and the radial runout of the tips of the first labyrinth teeth 4. The circumferential deformation of the rotor components is non-uniform. The circumferential non-uniformity at a certain azimuth of the rotor is marked as δ, and the circumferential non-uniform deformation is as Figure 6 shown.

[0090] An additional swirl guide vane 7 is arranged at the outlet of the first labyrinth teeth 4. The additional swirl guide vane 7 is connected to the first labyrinth bushing 6 and the combustion chamber inner ring 8 through bolts 9 to form a second chamber 2. Since both the additional swirl guide vane 7 and the combustion chamber inner ring 8 are stator components, the swirl coefficient of the second chamber 2 between them is very low, and no pressure gradient is formed in the radial direction, so there is no radial pressure difference. The pressure difference amplitude between the high-radius position P3 and the low-radius position P1 is very small, not exceeding 1%.

[0091] By controlling the distance between the additional swirl guide vane 7 and the pull rod 11, where the distance between the additional swirl guide vane 7 and the pull rod 11 is controlled within 1 - 2 mm, the accelerating effect of the Coriolis force of the radial internal flow in the disk cavity on the circumferential velocity of the air flow is enhanced, thereby increasing the swirl coefficient of the third chamber 3 between the additional swirl guide vane 7 and the pull rod 11, reducing the pressure P1 at the low-radius position, increasing the radial pressure drop from the inlet position P2 to the outlet position P1 of the first labyrinth teeth 4 in the third chamber 3, and the gas is discharged from the P2 position through the P1 position to the P3 position.

[0092] The reduction of the chamber pressure in the third chamber 3 can reduce the axial force on the rotating side of the third chamber 3 and reduce the forward axial force of the high-pressure rotor during takeoff or high-power operation of the engine.

[0093] Therefore, compared with the conventional air extraction technology, under the condition that the air extraction volume is the same as that of the conventional technical solution, in the present invention, due to the increased throttling and pressure reduction ability of the stepped first labyrinth teeth 4 with wear grooves in the honeycomb belt, a higher radial pressure drop is generated from the P1 position to the P2 position, and no radial pressure increase occurs from P2 to P3. In this solution, the air is extracted from the P3 position with the lowest pressure, which can minimize the forward axial force generated by the rotating components (pull rod 11 and labyrinth disk 5) from the P1 position to the P2 position, thereby greatly reducing the forward axial force of the high-pressure rotor during takeoff and other high-power operations of the engine, which is beneficial to ensuring the normal service life of the bearings.

[0094] Next, specific embodiments will be used to further illustrate the advantages of the technical solution of the present invention compared with the conventional technical solution.

[0095] In the embodiment of the present invention, multiple stepped inclined labyrinth teeth, namely the first labyrinth teeth 4, are designed on the labyrinth disc 5, with an average radius of 156 mm, a labyrinth clearance of 0.35 mm, and a stepped height of about 1 / 3 - 2 / 3 of the tooth height. And there is a honeycomb wear-resistant layer 10 on the bushing that mates with the labyrinth teeth. By converting between cold and hot states, a reasonable cold-state clearance between the first labyrinth teeth 4 and the honeycomb wear-resistant layer 10 is given. When the engine starts and runs to the hot state, the tip of the first labyrinth teeth 4 scrapes out a groove on the honeycomb wear-resistant layer. Under the condition that the labyrinth clearances are the same (compared with conventional stepped teeth), there will be local sharp turning and separation of the air flow passing through each labyrinth clearance. In this embodiment (with a worn groove on the honeycomb wear-resistant layer), it has a higher throttling and pressure-reducing ability than the conventional stepped inclined labyrinth teeth. The length of the worn groove is about 1 - 2 mm, and the depth is about 0.2 - 0.4 mm.

[0096] The swirl guide vane 7 is connected to the first labyrinth bushing 6 and the combustion chamber inner ring 8 through bolts. The distance between the swirl guide vane 7 and the pull rod 11 is controlled within 1 - 2 mm, increasing the radial velocity of the radially inward flow of the air, thereby enhancing the Coriolis force. In the radially inward flow, the Coriolis force plays a role in enhancing the radial pressure drop of the air flow, thus significantly increasing the radial pressure drop from P2 to P1 in the third chamber 3.

[0097] The second chamber 2 is mainly composed of the swirl guide vane 7 and the combustion chamber inner ring 8, both of which are stator components. Therefore, a second chamber 2 without a radial pressure difference is formed between the swirl guide vane 7 and the combustion chamber inner ring 8. The pressure in the second chamber 2 is the lowest (P2 > P1 = P3) and evenly distributed. The air bleeding position point is selected at the P3 position point with the lowest pressure. On the premise of ensuring the same air bleeding volume, P3 can reach a lower pressure level, which is beneficial to reducing the axial force on the rotating side of the third chamber 3.

[0098] Based on the static pressure of 1600 kPa at the air bleeding position point of the last-stage axial compressor of the engine, referring to Figure 4 is the streamline of the middle section of the stepped teeth and Figure 5 is the streamline of the middle section of the stepped teeth with a worn groove on the honeycomb belt. It can be seen from the figure the structure of the stepped teeth with a worn groove on the honeycomb belt of the present invention. The air flow passing through each labyrinth clearance has a sharp turning and separation, forming a recirculation zone at the tip position of the labyrinth teeth, reducing the effective leakage clearance of the labyrinth teeth, thereby reducing the labyrinth leakage coefficient, improving the throttling ability, and reducing the pressure in the rear chamber of the labyrinth teeth. And combined with the leakage coefficient comparison diagram shown in Figure 7 , it can be known that for the stepped inclined labyrinth teeth with a worn groove on the honeycomb belt involved in the present invention, there is local sharp turning and separation loss at the top of each labyrinth tooth of the air flow. Its leakage coefficient is reduced by about 30% compared with the conventional stepped inclined teeth. The above technical solutions are calculated by relevant numerical CFD (Computational Fluid Dynamics), such as Figure 8 shows the conventional scheme with an exhaust of 1.2%, such as Figure 9 shows the conventional scheme with an exhaust of 3%, such asFigure 10 Shown is the swirl coefficient of the conventional technical solution with 1.2% exhaust air, as Figure 11 Shown is the technical solution of the present invention with 1.2 exhaust air, as Figure 12 Shown is the swirl coefficient of the technical solution of the present invention with 1.2% exhaust air. The ratio of the circumferential velocity C of the air swirl outside the boundary layer in the disk cavity to the circumferential velocity of the local rotor surface is defined as the swirl coefficient, which mainly measures the strength of the circumferential velocity of the air flow. The larger the swirl coefficient, the higher the circumferential velocity of the air flow.

[0099] As Figure 10 Shown is that the swirl coefficient of chamber 2 of the conventional technical solution with 1.2% exhaust air is about 0.4. In the technical solution of the present invention, by using the principle that the radial inward Coriolis force accelerates the circumferential velocity of the air flow, the radial inward flow velocity is enhanced through the guide plate, thereby enhancing the acceleration effect of the Coriolis force on the circumferential velocity of the air flow, and the swirl coefficient of chamber 3 is increased to 0.8 ( Figure 12 ), thereby increasing the radial pressure drop from the high radius to the low radius in chamber 3.

[0100] Through Figure 5 Comparison shows that under the condition of ensuring the same air release volume (1.2% air release), the axial force of the disk cavity adopting the air extraction scheme of the present invention is reduced by 1565 kgf compared with the conventional scheme. If the conventional scheme wants to achieve the same axial force adjustment effect as the present invention, the air release volume needs to be increased to 2.5%, but increasing the air release volume to 2.5% has a greater impact on the engine performance.

[0101] Under the condition of ensuring the same air release volume (1.2% air release), the axial force of the disk cavity adopting the air extraction scheme of the present invention is reduced by 1565 kgf (Table 1) compared with the conventional scheme. If the conventional scheme wants to achieve the same axial force adjustment effect as the present invention, the air release volume needs to be increased to 3%, which has a greater impact on the engine performance.

[0102] Since the axial force of the high-pressure rotor of the engine is the vector sum of the aerodynamic forces of each stage of the disk cavity and the blades, the technical solution of the present invention can reduce the axial force of the high-pressure rear disk cavity of the last-stage axial compressor by 1565 kgf, that is, reduce the axial force of the high-pressure rotor of the engine by 1565 kgf, providing favorable conditions for the normal working service life of the bearing.

[0103] Table 1 Comparison of disk cavity axial forces (positive backward, air release volume 1.2%)

[0104]

[0105] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An air extraction device for the last-stage axial-flow compressor to adjust the axial force of the rotor, characterized in that The device includes a first labyrinth seal (4), a honeycomb wear-resistant layer (10), a swirl guide vane (7), a pull rod (11), and a combustion chamber inner ring (8), where a certain gap is formed between the first labyrinth seal (4) and the honeycomb wear-resistant layer (10); a swirl guide vane (7) is arranged at the outlet of the first labyrinth seal (4), and a second chamber (2) is formed between the swirl guide vane (7) and the combustion chamber inner ring (8); a third chamber (3) is formed between the swirl guide vane (7) and the pull rod (11), and a P1 position point is arranged at the outlet of the third chamber (3); the device further includes a last-stage compressor disk (12), a labyrinth seal disk (5), a second labyrinth seal (14), a first labyrinth seal bushing (6), a second labyrinth seal bushing (15), a first bolt (9), a second bolt (13), and a third bolt (16), where a first chamber (1) is formed between the last-stage compressor disk (12) and the labyrinth seal disk (5); an air extraction port is arranged between the top end of the last-stage compressor disk (12) and the first labyrinth seal bushing (6), and the honeycomb wear-resistant layer (10) is arranged on the bottom surface of the first labyrinth seal bushing (6); the last-stage compressor disk (12) is provided with an extension rod which is fixedly connected with the labyrinth seal disk (5) through a second bolt (13), the other side of the labyrinth seal disk (5) is connected with the pull rod (11), the first labyrinth seal (4) is arranged at the end of the labyrinth seal disk (5), and a P2 position point is arranged at the outlet of the first labyrinth seal (4); the second labyrinth seal bushing (15) is fixed inside the end of the combustion chamber inner ring (8) through a third bolt (16), and the second labyrinth seal (14) is located inside the tail of the pull rod (11) and below the second labyrinth seal bushing (15); the swirl guide vane (7), the first labyrinth seal bushing (6), and the combustion chamber inner ring (8) are fixedly connected through a first bolt (9), and a bleed point P3 position is arranged at the upper end of the combustion chamber inner ring (8); the pull rod (11) is arranged in a long strip shape; the distance between the swirl guide vane (7) and the pull rod (11) is controlled to be 1 - 2 mm, so as to increase the swirl coefficient of the third chamber (3) and improve the radial pressure drop from the radial internal flow air extraction P2 to P1.

2. The device according to claim 1, wherein the size of the gap is used to satisfy that the first labyrinth seal (4) scrapes out a groove around on the honeycomb wear-resistant layer (10), the length of the worn groove is 1 - 2 mm, and the depth is 0.2 - 0.4 mm.

3. The device according to claim 2, wherein the distance of the gap is obtained by calculating the thermal expansion deformation amount and rotational centrifugal deformation amount of the first labyrinth seal (4), the radial clearance of the bearing, the radial runout amount of the tip of the first labyrinth seal (4), and the thermal expansion deformation amount of the honeycomb wear-resistant layer (10). Specifically, the gap calculation formula is as follows: In the formula, Δr is the radial clearance at the design point, ΔLs is the radial elongation amount of the stator part, and ΔLr is the radial elongation amount of the rotor part.

4. The device according to claim 2, wherein the groove is used to enhance the throttling and pressure reduction ability of the first labyrinth seal (4) and reduce the pressure at the P2 position point at the outlet of the first labyrinth seal (4).

5. The device according to claim 1, wherein the first labyrinth (4) is a multi-step inclined labyrinth, where the number of steps is 3 to 6, and the step height is 1 / 3 to 2 / 3 of the tooth height; the honeycomb wear-resistant layer (10) is located at the bottom of the first labyrinth bushing (6) and above the first labyrinth (4); the first labyrinth bushing (6), the honeycomb wear-resistant layer (10) cooperate with the multi-steps of the first labyrinth (4).

6. The device according to claim 1, wherein the second labyrinth bushing (15) is L-shaped, one end of the L-shape is fixed to the clamping block at the tail end of the combustion chamber inner ring (8) by a third bolt (16), and the other end of the L-shape is in parallel cooperation with the tooth tip of the second labyrinth (14).

7. The device according to claim 1, wherein the area of the third chamber (3) is smaller than that of the second chamber (2); the swirl coefficient of the third chamber (3) is higher than that of the second chamber (2) during the air extraction process; during the air extraction process of the second chamber (2), the internal static pressure distribution is uniform, and the radial pressure difference < 1%.

8. The device according to claim 1, wherein the tie rod (11), the combustion chamber inner ring (8), the labyrinth disc (5) and the last-stage compressor disc (12) are integrally formed parts.

9. The device according to any one of claims 1-7, wherein the last-stage compressor disc (12), the labyrinth disc (5), the tie rod (11), the first labyrinth (4), the second labyrinth (14) are rotating parts; the first labyrinth bushing (6), the honeycomb wear-resistant layer (10), the combustion chamber inner ring (8), the swirl increasing guide vane (7), the second labyrinth bushing (15) are stator parts.

10. An air extraction method for the last-stage axial-flow compressor to adjust the axial force of the rotor, characterized in that, Using the last-stage axial compressor air extraction device for adjusting the rotor axial force according to any one of claims 1-9, the method includes: When the engine runs from cold state to hot state, the gap between the first labyrinth (4) and the honeycomb wear-resistant layer (10) gradually decreases as the rotation speed increases, and the tooth tip of the first labyrinth (4) scrapes out a groove on the honeycomb wear-resistant layer (10). The air extraction through the groove can enhance the throttling and pressure reducing ability of the first labyrinth (4) and reduce the pressure at the P2 position at the outlet of the first labyrinth (4); By controlling the distance between the swirl increasing guide vane (7) and the tie rod (11), the radial velocity of the radially inward air extraction in the third chamber (3) is increased, the radial pressure drop from the P2 position at the outlet of the first labyrinth (4) to the P1 position at the outlet of the third chamber (3) is increased, and the gas is discharged from the P2 position through the P1 position to the P3 position; the third chamber (3) is formed by the swirl increasing guide vane (7) and the tie rod (11).

11. The method according to claim 10, wherein The method further includes, There is no radial pressure difference in the second chamber (2) formed by the swirl increasing guide vane (7) and the combustion chamber inner ring (8), and the pressure at the high-radius position P3 of the gas outlet inside the second chamber (2) is the same as the pressure at the low-radius position P1.

12. The method according to claim 10, wherein the first labyrinth (4) is a multi-step inclined labyrinth, where the number of steps is 3 to 6, and the step height is 1 / 3 to 2 / 3 of the tooth height; The honeycomb wear-resistant layer (10) is located at the bottom of the first labyrinth bush (6) and above the first labyrinth teeth (4); the first labyrinth bush (6), the honeycomb wear-resistant layer (10) and multiple steps of the first labyrinth teeth (4) are in fit with each other; The groove scraped by the tip of the first labyrinth teeth (4) on the honeycomb wear-resistant layer (10) has a length of 1-2 mm and a depth of 0.2-0.4 mm.

13. The method according to claim 10, wherein, The distance of the clearance is obtained by calculating the thermal expansion deformation amount and rotational centrifugal deformation amount of the first labyrinth teeth (4), the radial clearance of the bearing, the radial runout amount of the tip of the first labyrinth teeth (4), and the thermal expansion deformation amount of the honeycomb wear-resistant layer (10). Specifically, the clearance calculation formula is as follows: In the formula, Δr is the radial clearance at the design point, ΔLs is the radial elongation of the stator part, and ΔLr is the radial elongation of the rotor part.

14. The method according to claim 12, wherein, The groove can enhance the throttling and pressure-reducing capacity of the first labyrinth teeth (4) and reduce the pressure at the position of point P2 at the outlet of the first labyrinth teeth (4).

15. The method according to claim 10, wherein, The distance between the rotation-increasing guide vane (7) and the pull rod (11) is controlled within 1-2 mm; The reduction of the chamber pressure in the third chamber (3) can reduce the axial force on the rotating side of the third chamber (3) and reduce the forward axial force of the high-pressure rotor during takeoff or operation at a large state of the engine.

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