CN109707515B

CN109707515B - Impeller type wheel disc structure for gas turbine lubricating oil way system

Info

Publication number: CN109707515B
Application number: CN201811472856.3A
Authority: CN
Inventors: 刘红蕊; 刘军; 杜强; 柳光; 王沛; 徐庆宗; 杨晓洁; 李伟
Original assignee: Institute of Engineering Thermophysics of CAS
Current assignee: Institute of Engineering Thermophysics of CAS
Priority date: 2018-12-04
Filing date: 2018-12-04
Publication date: 2020-04-21
Anticipated expiration: 2038-12-04
Also published as: CN109707515A

Abstract

The invention provides an impeller type wheel disc structure for a gas turbine lubricating oil path system, wherein the gas turbine lubricating oil path system comprises a bearing cavity, an oil lubricating cavity and an impeller type wheel disc arranged between the bearing cavity and the oil lubricating cavity, the bearing cavity is communicated with the oil lubricating cavity through the impeller type wheel disc, a plurality of guide straight blades are uniformly arranged between a central cylinder and an annular body of the impeller type wheel disc along the circumferential direction, an oil return channel is formed in a space between every two adjacent guide straight blades, the cross section of each guide straight blade is in a wing shape, so that an inclined included angle is formed between the front edge of each guide straight blade and axial incoming flow, and the incoming flow is prevented from flowing and separating at the tail edge. Used lubricating oil flows from the bearing cavity into the lubricating oil cavity through each oil return passage. The impeller type wheel disc structure realizes the establishment of relatively stable pressure difference between the bearing cavity and the lubricating oil cavity while realizing the weight reduction of the wheel disc, ensures the stability of oil return and achieves the aims of high efficiency of lubricating oil supply and the economical efficiency of engine operation.

Description

Impeller type wheel disc structure for gas turbine lubricating oil way system

Technical Field

The invention relates to the field of gas turbine turbines, in particular to the field of aero-engine turbines, and more particularly relates to a novel impeller type wheel disc structure which is adopted in a lubricating oil return system of a turbine, so that the oil return smoothness of a lubricating oil path is effectively improved, the quality of the wheel disc is reduced, and the operation safety and the engine performance of the turbine are improved.

Background

The basic components of a modern aeroengine mainly comprise an air inlet channel, an air compressor, a combustion chamber, a turbine and a tail nozzle. Air enters the air compressor after being rectified by the air inlet channel to be compressed, then high-pressure air fuel oil is mixed in the combustion chamber to be combusted, high-temperature high-pressure gas is generated to rush to the turbine to do work, and the gas expanded by the turbine passes through the tail nozzle to increase the thrust of the engine. The work produced by the turbine provides on the one hand the engine power and on the other hand the compression work of the compressor.

In the process, the compressor and the turbine are always in a high-speed rotation state. In order to ensure the normal operation of the engine, a bearing which plays a supporting role for the engine and bears a certain axial force must be adopted. In order to reduce the friction of the bearing, take away heat and abrasion impurities generated by a friction surface and ensure that the inner ring of the bearing is fully cooled, the probability of the rubbing fault of the inner ring of the high-speed bearing is effectively reduced, and the lubrication of the bearing is the most important link for ensuring the safe and reliable operation of the bearing. For the complexity problems of bearing arrangement and a bearing lubricating oil system caused by the increase of the number and the types of rotating shafts and bearings in the engine, how to simply and effectively arrange the bearings and corresponding lubricating oil system pipelines has important significance for the high efficiency of the operation of the engine.

Chinese patent application CN201510219735.8 discloses a lubrication oil path system for at least two bearings adjacently arranged on a central shaft, wherein the lubrication oil cavities of the at least two bearing lubrication oil paths are arranged in a common cavity, and the lubrication oil of the at least two bearings flows to a common lubrication oil return port. In order to simplify the bearing lubricating oil system, the turbine disc is used as a connecting channel between the low-pressure turbine disc center and the bearing cavity and the lubricating oil cavity, and oil supply from the lubricating oil cavity to the bearing cavity is realized. Specifically, as shown in fig. 1 and 2, the lubricating oil chamber 601 of the lubricating oil path of the first bearing 302 and the lubricating oil path of the second bearing 301 are arranged in a common chamber, the upper part of the lubricating oil chamber 601 is communicated with the oil-air outlet 203, the lower part of the lubricating oil chamber 601 is communicated with the lubricating oil return port 204, and the lubricating oil from the first bearing 302 and the lubricating oil from the second bearing 301 flow to the lubricating oil return port 204. When the engine runs, lubricating oil enters the oil supply sleeve 202 in the tail end of the low-pressure shaft from the oil supply pipeline oil supply nozzle 201, and then the first bearing 301 and the second bearing 302 are lubricated and cooled from the inner ring through oil spray holes distributed on the low-pressure shaft respectively. Used lubricating oil enters the bearing cavity 403 and collects on the inner wall surface of the front packing ring 401. The inner wall surface of the front sealing ring 401 is a tapered cylinder with inclination, and the lubricating oil flows backwards along the inner wall surface of the front sealing ring under the action of gravity and flows into the front half section 102 of the tapered cylinder 101 on the T-shaped disc before the inclined support rib plate 106. The annular oil baffle boss 104 arranged in front of the sealing ring 102 can prevent lubricating oil from entering the low-pressure turbine disk cavity through the annular channel 403 at the tail end of the front sealing ring, so that the lubricating oil is prevented from leaking. The lubricating oil flowing into the inner wall surface of the front half-section 102 of the T-shaped disc conical cylinder flows into the rear half-section 103 of the T-shaped disc conical cylinder through the fan-shaped oil return channels 105 distributed on the inclined thin wall 106 of the T-shaped disc, continues to flow backwards and then enters the oil return pipeline 204. During actual operation of the engine, the bearing cavity 401 is filled with lubricating oil and oil gas. Because the lubricating oil has high viscosity, the lubricating oil flowing out of the bearing can be attached to the T-shaped disc, and the inclined wall surface on the T-shaped disc can play a role of an oil mist separator under the action of centrifugal force, so that the lubricating oil attached to the surface of the T-shaped disc is thrown onto the inner wall of the conical cylinder of the T-shaped disc and is converged with a main flow of the lubricating oil. Meanwhile, under the action of centrifugal force, the inclined inner wall of the conical cylinder is also favorable for the backflow of lubricating oil. The lubricating oil chamber 601 is also filled with lubricating oil and oil gas when the engine is running. The size of the conical cylinder of the T-shaped disc is increased, so that the space in the lubricating oil cavity can be enlarged, and the separation of lubricating oil and oil gas is facilitated. The completely separated oil gas can flow out from the oil gas pipeline 203, and the lubricating oil enters the lubricating oil return pipeline 204, so that the oil gas in the lubricating oil return pipeline is prevented from being mixed, and the recovery of the lubricating oil is not facilitated. The central cylinder of the T-shaped impeller disc is connected with the annular body by using the ribbed plates, the central cylinder 108 is sleeved on the end part of the central shaft, the adjacent ribbed plates are spaced in the circumferential direction to form a gap opening, or the ribbed plates are of a circular plate structure, and the circular plate structure is provided with a plurality of gap openings which are spaced at equal intervals in the circumferential direction and are close to the annular body; the annular body has an axially inner cylinder and an axially outer cylinder separated by ribs, and the lubricating oil from the bearing cavity 401 reaches the lubricating oil return port via the inner surface of the axially inner cylinder, the gap opening, and the inner surface of the axially outer cylinder in this order.

The simplified turbine T-impeller disc disclosed in chinese patent application CN201510219735.8 communicates with a bearing lubrication oil system while reducing the weight of the disc and simplifying the bearing lubrication oil system. However, the rib plate structure cannot play a role in increasing pressure at the inlet and the outlet of the rib plate structure, and cannot bring about pressure change, so that pressure difference between the bearing cavity and the lubricating oil cavity cannot be established, and the phenomenon of unstable oil supply of the lubricating oil cavity is caused. Therefore, in the case that the overall structure of the lubricating oil system remains unchanged, a new wheel disc structure ensuring smooth and efficient supply of lubricating oil is needed to establish a stable pressure difference between the bearing cavity 402 and the lubricating oil cavity 601.

Disclosure of Invention

In view of the above disadvantages and shortcomings of the prior art, the present invention is directed to provide a novel impeller type wheel disc structure for a lubrication oil path system of a multi-stage (multi-shaft) adjacent bearing in a gas turbine, especially an aero-engine, which can effectively eliminate the unstable oil supply phenomenon of a lubrication oil chamber, and establish a stable pressure difference between the bearing chamber and the lubrication oil chamber, thereby improving the oil return smoothness and efficiency of the lubrication oil path, reducing the wheel disc quality, and improving the safety of turbine operation and the engine performance.

In order to achieve the aim, the invention adopts the technical scheme that:

an impeller type wheel disc structure for a lubricating oil path system of a gas turbine, wherein,

the gas turbine lubricating oil path system comprises an impeller type wheel disc arranged on a central shaft, a bearing cavity arranged on the upstream of the impeller type wheel disc and a lubricating oil cavity arranged on the downstream of the impeller type wheel disc, wherein the bearing cavity is communicated with the lubricating oil cavity through the impeller type wheel disc,

the impeller type wheel disc comprises a central cylinder and an annular body which are coaxially arranged, the central cylinder is fixedly sleeved on the central shaft, the annular body is integrally a cylindrical part, the outer wall of the annular body is fixedly sleeved in a central hole of an impeller disc of the gas turbine, the impeller disc is a compressor disc or a turbine disc, the inner wall of the annular body is provided with an annular supporting wall,

it is characterized in that the preparation method is characterized in that,

the axial positions of the annular supporting wall and the central cylinder are at least basically the same, a plurality of guide straight blades are uniformly arranged between the annular supporting wall and the central cylinder along the circumferential direction, an oil return channel is formed in a space between every two adjacent guide straight blades, lubricating oil in the bearing cavity flows into the lubricating oil cavity through each oil return channel of the impeller type wheel disc, the cross section of each guide vane is in a wing shape, and the selection of wing shape parameters enables the flow of incoming flow in each oil return channel not to generate an obvious separation phenomenon.

The impeller type wheel disc structure for the lubricating oil path system of the gas turbine has the working principle that when an engine runs, the rotating impeller type wheel disc can play a role in pressurizing a working medium and suck lubricating oil and oil mist in a bearing cavity into an oil return lubricating oil cavity, so that on one hand, the lubricating oil in the bearing cavity is ensured to be pumped away in time, oil accumulation is avoided, on the other hand, the supply pressure of the lubricating oil in the bearing cavity is reduced, the supply of the lubricating oil is facilitated, on the third hand, the oil return pressure of the lubricating oil in the lubricating oil cavity is improved, and the recovery of the lubricating oil is facilitated.

Preferably, the central cylinder is fixed on the central shaft through a clamping groove and a screw, and a transition fillet is arranged at the joint of each guide straight blade, the annular supporting wall and the central cylinder.

Preferably, the junction of the annular supporting wall and the inner wall of the annular body is provided with a transition fillet.

Preferably, the inner wall of the annular body is divided into a front half and a rear half by the annular support wall, and the rear half has an outwardly flared inclination angle. Preferably, the inclination angle is 5-15 °.

Preferably, the number of the guide straight blades is determined according to the design pressure difference between the bearing cavity and the lubricating oil cavity and the amount of lubricating oil.

Preferably, the return passage is partially air-intake adjustable in relation to flow rate and stability.

Preferably, the leading edge of the wing profile of the guide straight blade adopts proper thickness and inlet installation angle, and the trailing edge of the blade adopts the smallest thickness and proper outlet installation angle to ensure the strength requirement of the blade and avoid the flow separation of the trailing edge.

Compared with the prior art, the impeller type wheel disc structure effectively solves the problems of unsmooth and unstable oil return between the bearing cavity and the lubricating oil cavity, realizes the establishment of relatively stable pressure difference between the bearing cavity and the lubricating oil cavity, and ensures the stability of oil supply and oil return; the impeller type wheel disc structure not only meets the torque transmission and supporting functions of the turbine, but also realizes the weight reduction of the wheel disc by the hollow structure under the condition of meeting the strength, and achieves the purposes of high efficiency of lubricating oil supply and economical efficiency of engine operation.

Drawings

FIG. 1 is a schematic diagram of a prior art gas turbine engine lubrication oil system;

FIG. 2 is a view of the T-shaped disk of FIG. 1 in the direction B;

FIG. 3 is a view of the impeller disk of the present invention in the direction B;

FIG. 4 is a sectional view H-H of the impeller disk of FIG. 3;

figure 5 is a C-C profile cross-sectional view of the impeller disk of figure 3.

Detailed Description

The present invention will be described in further detail with reference to examples, which are illustrative of the present invention and are not to be construed as being limited thereto.

Fig. 3 to 5 show an impeller type wheel disc structure suitable for a gas turbine lubricating oil system, as can be seen from the figures, the impeller type wheel disc of the present invention includes a central cylinder 101 and an annular body 102 which are coaxially arranged, the central cylinder 101 is fixedly sleeved on a central shaft of a gas turbine through a clamping groove and a screw, the annular body 102 is integrally a cylindrical component, an outer wall of the annular body is fixedly sleeved in a central hole of an impeller disc of the gas turbine, the impeller disc is a compressor disc or a turbine disc, an annular support wall 103 is arranged on an inner wall of the annular body 102, and a transition fillet is arranged at a connection position of the annular support wall and the inner wall of the annular body. The axial positions of the annular supporting wall 103 and the central cylinder 101 are basically the same, a plurality of guide straight blades 106 are uniformly arranged between the annular supporting wall and the central cylinder along the circumferential direction, a transition fillet is arranged at the joint of each guide straight blade, the annular supporting wall and the central cylinder, an oil return channel is formed in the space between two adjacent guide straight blades 106, the cross section of each guide straight blade 106 is in the shape of an airfoil, an inlet installation angle is arranged at the front edge of the airfoil, an outlet installation angle is arranged at the tail edge of the airfoil, so that an inclined included angle is formed between the front edge of each guide straight blade and an axial incoming flow, and the incoming flow is prevented from flowing and separating at the tail. According to the impeller type wheel disc structure, lubricating oil in the bearing cavity can flow into the lubricating oil cavity through each oil return channel of the impeller type wheel disc. When the engine runs, the rotating impeller type wheel disc can establish relatively stable pressure difference between the bearing cavity and the lubricating oil cavity, so that the lubricating oil in the bearing cavity flows into the lubricating oil cavity smoothly without blockage.

Further, the guide straight vane 106 may also be a three-dimensional twisted vane, and the number, height, shape and throat area thereof may be determined according to the pressure difference between the bearing cavity and the lubricant cavity, and the amount of lubricant required according to the mechanical design of the impeller. The vane passages can be partially air-intake to adjust the relationship between flow and stability. The vane passages may also take an inclined flow direction shape at an angle to the horizontal. The leading edge of the blade airfoil adopts proper thickness and an inlet mounting angle, and the trailing edge of the blade adopts the smallest thickness and the proper outlet mounting angle so as to ensure the strength requirement and avoid the flow separation of the trailing edge.

Preferably, the inner wall of the annular body is divided into a front half section 105 and a rear half section 107 by the annular supporting wall, and the rear half section 107 has an inclination angle which is expanded outwards and ranges from 5 degrees to 15 degrees.

The impeller type wheel disc structure can be preferably applied to the existing gas turbine lubricating oil circuit system shown in figure 1, and only the T-shaped disc 101 in the impeller type wheel disc structure is required to be replaced by the impeller type wheel disc structure. In fig. 1, 201 is an oil supply nozzle, 202 is an oil supply sleeve, 203 is an oil gas pumping pipeline, and 204 is an oil return pipeline; 301 is a low pressure rear bearing, 302 is a high pressure rear bearing; 401 is a front sealing ring, 402 is a front floating graphite sealing structure, 403 is a bearing cavity, and 404 is an annular channel at the tail end of the front sealing ring; 501 is a rear floating graphite sealing structure, and 502 is a rear sealing ring; 601 is a lubricating cavity; 602 is an end cap. The dashed arrows indicate the oil supply route of the oil (schematic view). When the engine runs, lubricating oil for lubricating the bearing enters the oil supply sleeve 202 in the tail end of the low-pressure shaft from the oil supply nozzle 201 of the lubricating oil system, and then the bearing is lubricated and cooled from the inner rings of the high-pressure rear bearing 302 and the low-pressure rear bearing 301 through oil injection holes distributed on the low-pressure shaft, so that oil supply under the ring is realized. Used lubricating oil flows out of the bearing and enters the bearing cavity 403, and the annular oil baffle boss 104 can prevent the lubricating oil in the front half section 105 of the conical cylinder from entering a low-pressure turbine disc cavity (shown in figures 3 and 4) through an annular channel 404 at the tail end of the front sealing ring, so that the lubricating oil is prevented from leaking. The lubricating oil flowing into the bearing cavity 403 flows into the lubricating oil cavity 601 (which is composed of the rear half 107 of the conical cylinder and the end cover 602) through the three-dimensional impeller passage 106 distributed inside the impeller disc support wall 103, continues to flow backwards, and then enters the oil return line 204. The inclined conical barrel inner wall facilitates the backflow of oil under the action of centrifugal force (as shown in fig. 3).

When the engine is running, the lubricating oil cavity 601 is filled with lubricating oil and oil gas. Through oil-gas separation, the completely separated oil gas flows out through the oil-gas pipeline 203, and the lubricating oil is discharged through the lubricating oil return pipeline 204, so that oil-gas mixing in the lubricating oil return pipeline is avoided, and the recovery of the lubricating oil is not facilitated. In order to prevent oil gas in the bearing cavity and the lubricating oil cavity from entering the turbine disc cavity, floating

graphite sealing structures

402 and 501 are arranged between the two ends of the outer ring of the impeller disc and the front sealing ring and the rear sealing ring. Alternatively, the sealing structure may also adopt other sealing structures such as a labyrinth seal, a contact graphite seal or a brush seal.

In addition, it should be noted that the specific embodiments described in the present specification may differ in the shape, name, and the like of the components and parts. Equivalent or simple variations of the constructions and features according to the principles and concepts described in the present patent are included in the scope of protection of the present patent. Those skilled in the art to which the invention relates will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

Claims

1. An impeller type wheel disc structure for a lubricating oil path system of a gas turbine, wherein,

it is characterized in that the preparation method is characterized in that,

the axial positions of the annular supporting wall and the central cylinder are basically the same, a plurality of guide straight blades are uniformly arranged between the annular supporting wall and the central cylinder along the circumferential direction, an oil return channel is formed in a space between every two adjacent guide straight blades, lubricating oil in the bearing cavity flows into the lubricating oil cavity through each oil return channel of the impeller type wheel disc, the cross section of each guide vane is in a wing shape, and the flow of the incoming flow in each oil return channel is not obviously separated due to the selection of wing shape parameters.

2. The impeller-type disk structure of claim 1, wherein the central cylinder is fixed to the central shaft by a clamping groove and a screw, and a transition fillet is provided at the joint of each of the guide straight blades, the annular support wall and the central cylinder.

3. The impeller-type disk structure of claim 1, wherein a junction of the annular support wall and the annular body inner wall is provided with a transition radius.

4. The impeller-type disk structure of claim 1, wherein the inner wall of the annular body is divided into a front half and a rear half by the annular support wall, the rear half having an outwardly flared oblique angle.

5. The impeller-type wheel disc structure according to claim 1, wherein the number of said guide straight vanes is determined according to a design pressure difference between said bearing cavity and a lubricating oil cavity and an amount of lubricating oil.

6. The impeller disc structure of claim 1, wherein said oil return passages are partially air intake to adjust flow and stability relationships.

7. The impeller-type disk structure of claim 1, wherein the leading edge of the airfoil of the guide straight vane has a suitable thickness and inlet installation angle, and the trailing edge of the vane has a thickness as small as possible and an appropriate outlet installation angle, so as to ensure the strength requirement of the vane and avoid flow separation of the trailing edge.

8. The impeller-type wheel disc structure of claim 4, wherein an annular oil baffle boss is arranged in the front half section, the oil baffle boss is in radial contact with the front sealing ring, and the axial distance between the oil baffle boss and the tail end of the front sealing ring is 3-8 mm.

9. A gas turbine lubricating oil passage system having the impeller disk structure of any one of claims 1 to 8.