An airfoil labyrinth seal structure for an aeroengine bearing chamber

Abstract

A labyrinth seal structure for an aero-engine bearing chamber. The bearing chamber is arranged between the main shaft and the casing and is formed by an inner bearing ring, a bearing, an outer bearing ring, an oil collecting ring and the labyrinth seal structure. The labyrinth seal structure is axially arranged on both sides of the bearing chamber. The labyrinth seal structure has a stationary seal and a rotating seal that rotate relative to each other around the same axis. The stationary seal is sleeved outside the rotating seal. An anti-sealing protection layer is arranged inside the stationary seal. A number of sealing labyrinth teeth are arranged outside the rotating seal. At least one groove is arranged on the surface of the anti-sealing protection layer, and the depth of the groove is less than the thickness of the surface of the anti-sealing protection layer.

Description

Technical Field

[0001] The present invention belongs to the field of aero-engines, and particularly relates to a labyrinth seal structure for a bearing chamber and an aero-engine. Background Art

[0002] In rotary machines such as aero-engines, gas leakage between the rotating parts of the main shaft in the bearing chamber, the stationary bushing, and the bearing chamber casing will lead to a decrease in the overall propulsion efficiency of the engine and an increase in the lubricating oil consumption. For an aero-engine, improving the sealing ability in this area, increasing the pressure difference before and after the sealing section while reducing the high-temperature peripheral gas entering the bearing chamber from the sealing section, can reduce the thermal load of the bearing chamber and reduce the lubricating oil consumption. The sealing ability directly affects performance parameters such as the fuel consumption rate and propulsion efficiency of the engine. Therefore, it is very necessary to ensure a good sealing effect as much as possible.

[0003] As the most common seal structure form in aero-engines, the labyrinth seal structure is widely used in various components of the engine. The labyrinth seal relies on the airflow from the high-pressure area passing through the narrow gaps formed by several labyrinth teeth and a flat honeycomb structure and the cavities between two labyrinth teeth to achieve pressure reduction, thereby reducing leakage. When the airflow passes through the first labyrinth tooth gap, the flow rate increases and the pressure decreases; when it flows into the cavity between two labyrinth teeth, the gas expands, generating turbulence that causes energy loss of the airflow, and both the pressure and velocity of the airflow will decrease. In this way, after passing through several labyrinth teeth, the pressure difference before and after the labyrinth teeth decreases, and the gas flow rate passing through the labyrinth tooth gap also decreases, thereby reducing the overall leakage amount.

[0004] However, in the actual application of the existing labyrinth seal structure in the bearing chamber, the effect is not ideal. Especially when the aero-engine is in a low state, the following problems usually occur:

[0005] 1. Since the pressure inside the bearing chamber is higher than that of the surrounding chambers, gas or lubricating oil in the bearing chamber will leak, affecting the gas temperature between the bearing chamber and other external chambers, increasing the air extraction load, and affecting the performance of the aero-engine.

[0006] 2. The operation of an aero-engine requires ensuring bearing lubrication. There is a lubricating oil flow path for maintaining circulation inside the bearing chamber. Since the temperature of the lubricating oil will rise after running in the bearing chamber for a period of time, it needs to be led to the external casing through the circulation flow path for cooling to ensure that the lubricating oil continues to work at a more appropriate temperature. Due to the pressure inside the bearing chamber being higher than that of the surrounding chambers, the lubricating oil inside the bearing chamber may leak, affecting the working efficiency of the bearing, and the leaked lubricating oil will also cause further safety hazards to the aero-engine;

[0007] 3. During the working process, there is a gap between the rotor and the stator in the bearing cavity. The gas excitation force will cause forced vibration of the bearing cavity components. When the frequency of the excitation force is the same as the natural frequency of the components, resonance will occur, resulting in serious consequences.

[0008] 4. Due to the narrow installation space of the bearing cavity of the aero-engine, during the disassembly and assembly process along the axial direction, it is easy to cause rubbing between the rotor and the stator of the sealing structure. Moreover, an overly complex sealing structure not only makes processing difficult but also brings additional difficulties and workload to the disassembly and assembly of the bearing cavity. Summary of the Invention

[0009] Due to the technical problems existing in the actual application of the labyrinth sealing structure of the prior art solution in the bearing cavity of the aero-engine, the object of the present invention is to provide a labyrinth sealing structure for the bearing cavity of the aero-engine, to solve the above-mentioned technical problems existing in the prior art solution, optimize the sealing effect of the bearing cavity, reduce the leakage amount, and improve the performance of the engine.

[0010] The technical solution of the labyrinth sealing structure for the bearing cavity of the aero-engine provided by the present invention is as follows: A labyrinth sealing structure for the bearing cavity of the aero-engine, the bearing cavity is arranged between the main shaft and the casing, and is formed by the bearing inner ring, the bearing, the bearing outer ring, the oil collecting ring and the labyrinth sealing structure. The labyrinth sealing structure is axially arranged on both sides of the bearing cavity. The labyrinth sealing structure has a sealing stator and a sealing rotor that rotate relative to each other around the same axis. The sealing stator is sleeved outside the sealing rotor. A sealing protective layer is arranged on the inner side of the sealing stator. A plurality of sealing labyrinth teeth are arranged on the outer side of the sealing rotor. At least one groove is arranged on the surface of the sealing protective layer, and the depth of the groove is less than the thickness of the surface of the sealing protective layer.

[0011] Preferably, the groove is arranged on the opposite surface of the interval formed by two adjacent sealing labyrinth teeth, and the width of the groove is less than the interval formed by two adjacent sealing labyrinth teeth.

[0012] Preferably, the groove includes a first groove and a second groove, and the first groove and the second groove are respectively axially arranged at both ends of the labyrinth sealing structure.

[0013] Preferably, the grooves are circumferentially and discontinuously distributed on the surface of the sealing protective layer.

[0014] Preferably, the grooves are discontinuously distributed at 90 degrees, and the circumferential angle of each section of the groove is between 50 degrees and 70 degrees.

[0015] Preferably, the cross-sectional shape of the groove along the axial direction of the bearing cavity is semi-circular.

[0016] Preferably, the cross-sectional shape of the groove along the axial direction of the bearing cavity is rectangular.

[0017] Preferably, the sealing protection layer is a honeycomb structure or a wear-resistant coating.

[0018] Preferably, from the root to the top of the sealing labyrinth teeth, the cross-sectional area gradually decreases, and the top width of the sealing labyrinth teeth is close to 0.

[0019] In addition, the present invention also provides an aero-engine, which includes a compressor, a combustion chamber and a turbine, wherein the compressor and / or the turbine includes a plurality of bearing chambers, and the bearing chamber includes the labyrinth sealing structure according to any one of the foregoing.

[0020] By applying the labyrinth sealing structure of the bearing chamber and the aero-engine proposed by the present invention, the problems existing in the prior art can be solved from the source, bringing the following advantages:

[0021] First, the labyrinth sealing structure of the bearing chamber of the aero-engine provided by the present invention can disrupt the boundary layer, generate eddy currents, and reduce gas leakage. When the air flow passes through the narrow gap of the labyrinth teeth, the groove structure can disrupt the boundary layer of the air flow on the honeycomb surface, generate eddy currents, cause energy dissipation, strengthen the blocking effect of each single-stage labyrinth tooth in the labyrinth sealing structure on the air flow, thereby reducing gas leakage, ensuring the sealing effect between the two chambers, and improving the efficiency and performance of the engine;

[0022] Second, the labyrinth sealing structure of the bearing chamber of the aero-engine provided by the present invention can accommodate the lubricating oil in the bearing chamber and reduce the lubricating oil leakage in the low state. When the engine is operating in the low state, the pressure in the bearing chamber is greater than that outside the chamber, and there is a risk of lubricating oil leaking out through the labyrinth sealing. The groove structure can increase the pressure reduction effect of a single-stage labyrinth tooth and improve the sealing effect, thereby reducing the risk of lubricating oil leakage;

[0023] Third, in the labyrinth sealing structure of the bearing chamber of the aero-engine provided by the present invention, as a special connection method between the rotor part and the stator part, there is a gas excitation force during the working process. Adding the groove structure can increase the capacity of the chamber between the labyrinth teeth, reduce the gas impact force on the sealing position, and is beneficial to reducing the vibration of the aero-engine during operation;

[0024] Fourth, the labyrinth sealing structure of the bearing chamber of the aero-engine provided by the present invention can effectively reduce the axial rubbing during the installation process and is convenient for installation. Due to the narrow space of the bearing chamber, while ensuring the improvement of the sealing efficiency, the reliability and feasibility of the assembly and disassembly processes can also be ensured;

[0025] Fifth, the labyrinth sealing structure of the bearing chamber of the aero-engine provided by the present invention has a simple structure, can be applied to various sealing surfaces such as honeycomb structures and wear-resistant coatings, is easy to process, and has better processability compared with other sealing forms of structures.

[0026] For those familiar with the technical field, these and other objectives and advantages will become more apparent after reading the following parts of this specification in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The above summary of the invention and the following detailed description of the invention will be better understood when read in conjunction with the accompanying drawings. It should be noted that the drawings are only examples of the claimed invention. In the drawings, the same reference numerals represent the same or similar elements.

[0028] Figure 1 The figure shows a schematic diagram of the bearing chamber structure of the aeroengine of the present invention.

[0029] Figure 2 The figure shows a partially enlarged schematic diagram of the labyrinth seal structure of the bearing chamber of the first preferred embodiment of the present invention.

[0030] Figure 3 It is a schematic diagram of the conventional labyrinth seal structure of the bearing chamber in the prior art.

[0031] Figure 4 The figure shows a circumferential structure schematic diagram of the labyrinth seal structure of the bearing chamber of the second preferred embodiment of the present invention.

[0032] Figure 5 The figure shows a groove structure schematic diagram of the labyrinth seal structure of the bearing chamber of the third preferred embodiment of the present invention.

[0033] Figure 6 The figure shows a groove structure schematic diagram of the labyrinth seal structure of the bearing chamber of the fourth preferred embodiment of the present invention.

[0034] The reference numerals are as follows:

[0035] 100, labyrinth seal structure

[0036] 110, stationary seal

[0037] 111, seal protection layer

[0038] 112, groove

[0039] 1121, first groove

[0040] 1122, second groove

[0041] 120, rotating seal

[0042] 121, labyrinth teeth

[0043] 200, bearing inner ring

[0044] 300, bearing stator outer ring seat

[0045] 400. Bearing

[0046] 500. Oil collecting ring

[0047] 600. Main shaft

[0048] L1. Groove width

[0049] L2. Spacing width formed by two adjacent sealing labyrinth teeth

[0050] S1. Groove depth

[0051] S2. Thickness of sealing protective layer

[0052] α. Circumferential angle of groove Detailed implementation manners

[0053] The detailed features and advantages of the present invention are described in detail in the following detailed implementation manners. The content is sufficient for any person skilled in the art to understand the technical content of the present invention and implement it accordingly. And according to the specification, claims and drawings disclosed in this specification, those skilled in the art can easily understand the relevant purposes and advantages of the present invention.

[0054] Figures 1 to 2 The technical solution of the labyrinth seal structure of the bearing chamber of the aero-engine provided by the present invention is shown. The bearing chamber is arranged between the main shaft 600 of the aero-engine and the casing (not shown in the figure), and is formed by the inner bearing ring 200, the bearing 400, the bearing stator outer ring seat 300, the oil collecting ring 500 and the labyrinth seal structure 100. The labyrinth seal structure 100 is axially arranged on both sides of the bearing chamber.

[0055] Among them, the labyrinth seal structure 100 has a sealing stator 110 and a sealing rotor 120 that rotate relative to each other around the same axis. The sealing stator 110 is sleeved on the radially outer side of the sealing rotor 120. A sealing protective layer 111 is provided on the inner side of the sealing stator 110. The sealing protective layer can be a honeycomb structure or a wear-resistant coating to extend the service life of the labyrinth seal structure. A plurality of sealing labyrinth teeth 121 are provided on the outer side of the sealing rotor 120. From the root to the top of the sealing labyrinth teeth, the cross-sectional area gradually decreases, and the top width of the sealing labyrinth teeth is close to 0. The sealing labyrinth tooth structure of the present invention is not limited to the above form, and in other embodiments, various traditional labyrinth tooth forms including straight teeth can be adopted.

[0056] The surface of the sealing protection layer 111 is provided with two annular grooves 112, namely the first groove 1121 and the second groove 1122, which are both arranged on the opposite surfaces of the intervals formed by adjacent two sealing labyrinth teeth, and are respectively axially arranged at both ends of the labyrinth tooth sealing structure. The cross-sections of the first groove 1121 and the second groove 1122 are semi-circular, their widths (diameters) L1 are equal, and are both smaller than the width L2 of the interval formed by adjacent two sealing labyrinth teeth. The depth (radius) S1 of the groove 112 is smaller than the thickness S2 of the sealing protection layer 111.

[0057] During operation, under the action of the huge pressure difference between the outside and the inside of the bearing cavity, the air flow flows axially along the aero-engine main shaft 6 towards the inside of the bearing cavity. While in the low operating state, the pressure inside the bearing cavity is greater than that outside the cavity, and it is necessary to prevent the air flow from flowing axially along the aero-engine main shaft 6 towards the outside of the bearing cavity. By applying the sealing labyrinth tooth structure of the present invention, no matter in what operating state, after the air flow passes through the narrow gap between the first-stage labyrinth teeth on both sides of the bearing cavity and the sealing protection layer, it immediately enters the first groove 1121 or the second groove 1122 on the surface of the sealing protection layer inside the sealing stator 110. Through this groove structure, the boundary layer of the air flow on the surface of the sealing protection layer of the sealing structure can be destroyed, eddy currents are generated on the surface of the sealing protection layer 111, the degree of air flow energy dissipation is strengthened, the blocking effect of the single-stage labyrinth teeth on the air flow is enhanced, thereby reducing the gas leakage. And the groove structure further increases the volume of the space between the two-stage labyrinth teeth, increases the pressure reduction effect of each stage of labyrinth teeth, thereby ensuring the sealing effect between the inside and the outside of the bearing cavity and improving the efficiency and performance of the engine.

[0058] Secondly, by arranging the groove structure in the sealing protection layer 111, it is possible to allow a part of the lubricating oil to be accommodated inside the sealing protection layer when the aero-engine is in a low state, because the leakage of the lubricating oil inside the bearing cavity may cause potential safety hazards to the aero-engine.

[0059] Thirdly, the groove structure in the sealing protection layer 111 can increase the capacity of the chamber formed between the labyrinth teeth, reduce the gas impact force on the sealing position, and is beneficial to reducing vibration. At the same time, since the groove structure is arranged on the sealing stator 110 and does not modify the sealing rotor, the phenomenon of circumferential non-uniformity on the sealing rotor is avoided, which may cause more serious excitation force and rotor imbalance, and can better ensure the balance state of the rotor.

[0060] When disassembling and assembling the bearing cavity, since the sealing stator 110 of the technical solution of the present invention is sleeved outside the sealing rotor 120, there is no complex matching structure between the sealing stator and the sealing rotor, and it can be directly disassembled and assembled axially, which can effectively avoid the axial rubbing between the sealing stator and the sealing rotor during the disassembly and assembly process, and no additional tools are required, greatly reducing the workload of disassembly and assembly.

[0061] Figure 4Figure 2 shows the second preferred embodiment of the labyrinth seal structure of the bearing chamber of an aero-engine provided by the present invention, which shows the circumferential distribution of the annular grooves of the labyrinth seal structure. The axial structure of the labyrinth seal structure can be referred to Figure 2 as shown.

[0062] The labyrinth seal structure 100 has a stationary seal 110 and a rotating seal 120 that rotate relative to each other around the same axis. The stationary seal 110 is sleeved on the radially outer side of the rotating seal 120. A seal protection layer 111 is provided on the inner side of the stationary seal 110. The seal protection layer can be a honeycomb structure or a wear-resistant coating to extend the service life of the labyrinth seal structure. A number of labyrinth teeth 121 are provided on the outer side of the rotating seal 120. From the root to the top of the labyrinth teeth, the cross-sectional area gradually decreases, and the width of the top of the labyrinth teeth is close to 0.

[0063] Two circles of annular grooves 112, namely the first groove 1121 and the second groove 1122, are provided on the surface of the seal protection layer 111. They are both arranged on the opposite surfaces of the intervals formed by adjacent two labyrinth teeth, and are respectively axially arranged at both ends of the labyrinth seal structure. The widths L1 of the first groove 1121 and the second groove 1122 are equal, and are both smaller than the width L2 of the interval formed by adjacent two labyrinth teeth. The depth S1 of the groove 112 is smaller than the thickness S2 of the seal protection layer 111.

[0064] Among them, the first groove 1121 and the second groove 1122 are each circumferentially distributed on the circumferential surface of the seal protection layer 111 in four sections at intervals of 90 degrees, and the circumferential angle α of each section of the groove is 60 degrees.

[0065] Since there will be a circumferential flow in the rotational direction between the top of the labyrinth teeth and the seal protection layer 111 when the labyrinth teeth 121 rotate with the main shaft 6, by arranging the groove structure discontinuously in the circumferential direction, when the air flow passes through the gap between the top of the labyrinth teeth and the seal protection layer 111 in the circumferential direction, the groove structure disrupts the regular movement of the air flow in the circumferential direction, causing the air flow to expand at each section of the groove, generating turbulent flow and resulting in energy loss of the air flow. The pressure and velocity of the air flow will both decrease. Part of the energy is dissipated as heat energy. At the discontinuous part of the groove, the air flow velocity further increases, the pressure decreases, and the leakage amount of the labyrinth tooth structure is further reduced, improving the sealing effect.

[0066] In other embodiments, the circumferential angle α and the circumferential distribution number of each section of the groove can be selected with reference to factors such as the installation position, working conditions, and installation space of the labyrinth seal structure. The preferred axial angle is between 50 degrees and 70 degrees.

[0067] Figure 5 and Figure 6 Figure 3 shows other preferred embodiments of the labyrinth seal structure of the bearing chamber of an aero-engine provided by the present invention.

[0068] As Figure 5 shown, the third embodiment of the labyrinth seal structure of the aero-engine bearing chamber provided by the present invention is that several annular grooves are arranged on the surface of the seal protection layer. The number of the annular grooves is one less than the number of the labyrinth teeth. The annular grooves are all arranged on the opposite surfaces of the intervals formed by two adjacent labyrinth teeth. The cross-section thereof is semi-circular, and the width (diameter) L1 thereof is equal, and is less than the width of the interval formed by two adjacent labyrinth teeth. The depth (radius) S1 of the groove is less than the thickness of the seal protection layer 111.

[0069] By arranging a plurality of groove structures, the air leakage of the seal structure is further reduced, and the overall seal effect of the labyrinth seal structure is improved.

[0070] As Figure 6 shown, the fourth embodiment of the labyrinth seal structure of the aero-engine bearing chamber provided by the present invention

[0071] is that several annular grooves are arranged on the surface of the seal protection layer. The number of the annular grooves is one less than the number of the labyrinth teeth. The annular grooves are all arranged on the opposite surfaces of the intervals formed by two adjacent labyrinth teeth. The cross-section thereof is rectangular, and the width L1 in the axial direction thereof is equal, and is less than the width of the interval formed by two adjacent labyrinth teeth. The depth S1 of the groove is less than the thickness of the seal protection layer 111.

[0072] By adjusting the cross-sectional shape of the groove structure, in other embodiments, the geometric parameters of the groove can be selected with reference to factors such as the installation position, working conditions and installation space of the labyrinth seal structure.

[0073] The present invention also provides an aero-engine, including a compressor, a combustion chamber and a turbine. Among them, the labyrinth seal structure described above is included in the bearing chambers of the compressor and the turbine, so as to obtain a stronger seal effect and safety, and save the workload required for the disassembly and assembly of the bearing seat.

[0074] As can be seen from the above embodiments, by applying the bearing chamber labyrinth seal structure and the aero-engine provided by the present invention, the boundary layer of the air flow flowing through the labyrinth teeth can be destroyed, eddy currents can be generated, gas leakage can be reduced, the seal effect between the two side cavities can be ensured, and the efficiency and performance of the engine can be improved; the lubricating oil in the bearing chamber can be accommodated, the oil leakage in the low state can be reduced, and the seal effect can be improved; the groove structure can be increased to increase the capacity of the chamber between the labyrinth teeth, reduce the gas impact force on the seal position, and is beneficial to reducing vibration; the structure is simple and easy to process, and has good processability compared with other existing seal structure technical solutions; the axial rubbing during the installation process can be effectively reduced, and the installation is convenient. Due to the narrow space of the bearing chamber, while ensuring the improvement of the seal efficiency, the reliability and feasibility of the assembly and disassembly processes can also be ensured.

[0075] The terms and expressions used herein are for descriptive purposes only, and the present invention should not be limited to these terms and expressions. The use of these terms and expressions does not mean the exclusion of any equivalent features of any illustration and description (or parts thereof), and it should be recognized that various modifications that may exist should also be included within the scope of the claims. Other modifications, variations and substitutions may also exist. Accordingly, the claims should be regarded as covering all such equivalents.

[0076] Similarly, it should be noted that although the present invention has been described with reference to the current specific embodiments, those of ordinary skill in the art should recognize that the above embodiments are only used to illustrate the present invention, and various equivalent changes or substitutions can be made without departing from the spirit of the present invention. Therefore, as long as the changes and modifications of the above embodiments are within the scope of the spirit of the present invention, they will fall within the scope of the claims of this application.

Claims

1. A labyrinth seal structure for an aeroengine bearing chamber, the bearing chamber being disposed between the main shaft and the casing of the aeroengine, lubricating oil being contained in the bearing chamber, and the labyrinth seal structure being axially disposed on both sides of the bearing chamber to seal the bearing chamber. It is characterized in that: The labyrinth seal structure has a stationary seal and a rotating seal that rotate relative to each other about the same axis. The stationary seal is sleeved on the radial outer side of the rotating seal. A seal protection layer is provided on the inner side of the stationary seal. A plurality of seal labyrinth teeth are provided on the outer side of the rotating seal. The surface of the seal protection layer is provided with grooves at at least one position corresponding to the intervals formed by two adjacent seal labyrinth teeth. The depth of the grooves is less than the thickness of the seal protection layer. The grooves can accommodate the lubricating oil in the bearing chamber when the aeroengine is in a low state.

2. The labyrinth seal structure for an aeroengine bearing chamber according to claim 1, wherein The width of the grooves is less than the interval formed by two adjacent seal labyrinth teeth.

3. The labyrinth seal structure for an aeroengine bearing chamber according to claim 2, wherein The grooves include a first groove and a second groove, and the first groove and the second groove are axially disposed at both ends of the labyrinth seal structure respectively.

4. The labyrinth seal structure for an aeroengine bearing chamber according to claim 1, wherein The grooves are circumferentially distributed discontinuously and / or continuously on the surface of the seal protection layer.

5. The labyrinth seal structure for an aeroengine bearing chamber according to claim 4, characterized in that, The grooves are discontinuously distributed in four sections along 90 degrees, and the circumferential angle of each section of the grooves is between 50 degrees and 70 degrees.

6. The labyrinth seal structure for an aeroengine bearing chamber according to claim 1, characterized in that, The cross-sectional shape of the grooves along the axial direction of the bearing chamber is semicircular.

7. The labyrinth seal structure for an aeroengine bearing chamber according to claim 1, wherein The cross-sectional shape of the grooves along the axial direction of the bearing chamber is rectangular.

8. The labyrinth seal structure for an aeroengine bearing chamber according to claim 1, characterized in that, The seal protection layer is a honeycomb structure or a wear-resistant coating.

9. The labyrinth seal structure for an aeroengine bearing chamber according to claim 1, wherein From the root to the top of the seal labyrinth teeth, the cross-sectional area gradually decreases, and the width of the top of the seal labyrinth teeth is close to 0.

10. An aeroengine, the aeroengine comprising a compressor, a combustor and a turbine, wherein the compressor and / or the turbine comprises a plurality of bearing cavities, characterized in that, At least one of the bearing chambers has the labyrinth seal structure according to any one of claims 1-9.

Images