A method for designing a reverseable gas turbine sliding bearing pad oil supply device

Abstract

The application provides a design method of a reverseable gas turbine sliding bearing tile oil supply device, which comprises the following steps: S1, giving design input; S2, determining the number n of oil supply pipes; S3, determining the diameter phi of the oil supply pipes; S4, determining the positioning size L and alpha of the nozzle; S5, determining the diameter d and the spacing L of the nozzle; S6, calculating the oil flow; and S7, processing the reverseable gas turbine sliding bearing tile oil supply device meeting the design. K The design method scheme is reasonable, the design flow is clear, the guidance is strong, and the efficiency of the reverseable gas turbine sliding bearing tile oil supply device is greatly improved. The application is used in the domestic reverseable gas turbine sliding bearing design for the first time, and has very important reference value in the future gas turbine sliding bearing design.

Description

Technical Field

[0001] This invention belongs to the field of gas turbines and aero engines, and specifically relates to a design method for an oil supply device for sliding bearing pads of a reversible gas turbine. Background Technology

[0002] Compared to rolling bearings, sliding bearings are more suitable for high-thrust loads and high-speed operating environments. They are also less sensitive to damage from water, dust, and impurities. Sliding bearings tend to wear gradually, resulting in a long service life. Even if a sliding bearing fails, the machine can continue operating for a period to avoid accidents caused by sudden shutdowns. Sliding bearings also have advantages in manufacturing precision, difficulty, and cost compared to rolling bearings. Theoretically, sliding bearings are more suitable for the high-speed, high-thrust operating environment of gas turbines. However, sliding bearings are rarely used in gas turbines both domestically and internationally. This is mainly due to the following reasons: Firstly, gas turbines have a very compact structure and operate at extremely high temperatures, creating a harsh operating environment in the bearing area, making sliding bearings highly susceptible to damage at high temperatures. Secondly, gas turbines are used on ships, where the operating load environment is harsh, frequently subjected to ocean waves, resulting in complex operating environments such as pitching, rolling, yaw, swaying, and heave, subjecting the bearings to complex alternating loads and leading to failure. In reversible gas turbines, sliding bearings not only need to operate under high temperature, high speed, and high load conditions, but also need to operate stably under both forward and reverse rotation conditions. This further increases the design difficulty of sliding bearings, making their design one of the bottlenecks in the design of reversible gas turbines. The following problems and difficulties have arisen in the design and application of sliding bearings in reversible gas turbines:

[0003] Conventional sliding bearings used in steam turbines and various common machines typically handle relatively small loads, usually not exceeding 10 tons. However, the axial thrust of a gas turbine rotor cannot usually be balanced and eliminated within the machine, resulting in a very large thrust for sliding bearings. The thrust of medium-sized gas turbines is generally in the range of over 20 tons, and can even reach 40 tons. Furthermore, gas turbines have high power output and compact structures, operating at high temperatures and speeds. The operating environment for sliding bearings is extremely harsh, exceeding 100°C, reaching up to 120°C or even higher. Therefore, the design of sliding bearings in reversible gas turbines presents significant challenges.

[0004] Existing technology improvement methods: In the design of gas turbine bearings, mature tilting pad sliding bearings are usually selected in China, and Babbitt alloy pads are used. The working temperature of Babbitt alloy is usually below 80℃, and it will melt and fail when it works at 100℃. Improvements have also been made to the pad material, such as using lead bronze, to increase the working temperature of the pad.

[0005] One shortcoming of existing technology improvements is that, by selecting common tilting pad sliding bearing types and structures both domestically and internationally, common sliding bearings, under the high temperature, high speed, and high thrust of gas turbines, often experience wear at the edge of the pad, gradually expanding to the entire pad and leading to bearing failure. The main reason for this is that conventional bearings use nozzles or pads for lubrication, and the lubrication area only covers the middle of the pad. Figure 1 As shown, the edge area often suffers from insufficient oil, resulting in wear at the edge. Summary of the Invention

[0006] The purpose of this invention is to provide a design method for an oil supply device for sliding bearing pads of a reversible gas turbine.

[0007] A design method for an oil supply device for sliding bearing pads of a reversible gas turbine includes the following steps:

[0008] S1, given the design input;

[0009] S2, determine the number of oil supply pipes n;

[0010] S3, determine the oil supply pipe diameter φ;

[0011] S4, determine the nozzle positioning dimensions L and α;

[0012] S5, determine the nozzle diameter d and spacing L. K ;

[0013] S6, calculates the lubricating oil flow rate;

[0014] S7, machining the oil supply device for the sliding bearing pads of the reversible gas turbine that conforms to the design.

[0015] Furthermore, in S1, based on the spatial arrangement of the gas turbine sliding bearings and the dimensions of the gas turbine main shaft, the maximum outer diameter D0 of the bearing oil supply device cage and the minimum inner diameter D of the large nut are given. i .

[0016] Furthermore, in S2, based on the structural characteristics of the oil supply device, the number of oil supply pipes is equal to the number of sliding bearing pads.

[0017] Furthermore, the diameter of the oil supply pipe in S3 is constrained by the following parameters:

[0018] Based on the wrap angle of the sliding bearing design parameters, the distance L0 between the two bearing pads is determined. The following relationship exists between the distance between the bearing pads and the width B of the oil supply pipe:

[0019] L0=B+2δ (1)

[0020] φ=B-2t (2)

[0021] Where δ is the gap between the cage and the tile, usually 0.3mm≤δ≤0.5mm. This gap can ensure that the tile can swing freely in the cage and that the lubricating oil between the tiles can be discharged in time.

[0022] t is the wall thickness of the oil supply pipe, which is usually ≥3mm to ensure sufficient strength of the cage.

[0023] Furthermore, in S4, according to the working principle of the oil supply device, the diameter direction of the orifice should be directly opposite the oil inlet side and the oil outlet side of the bearing plate. In the design, the position and angle of the orifice can be accurately and quickly determined by using a three-dimensional model for positioning.

[0024] Furthermore, in step S5, to ensure the spraying effect of the nozzle, the diameter of the nozzle orifice K is 0.7mm ≤ d ≤ 3mm.

[0025] The working angle of the nozzle spray is greater than 60°. In order to ensure that the pad can be uniformly and fully lubricated along the oil inlet edge, the nozzle spacing has the following relationship.

[0026] L L ≤2*S*tan30° (3)

[0027] Where S is the distance from the nozzle to the edge of the tile.

[0028] Furthermore, in step S6, the lubricating oil flow rate is adjusted by adjusting the nozzle diameter and the spacing between the oil injection holes to meet the design requirements of the sliding bearing.

[0029] Furthermore, during the processing in S7, the orifice diameter d should be processed according to the design minimum value or with allowance. Before installation, a lubricating oil flow test should be performed to measure the flow rate and adjust the nozzle orifice diameter d to meet the design requirements.

[0030] The beneficial effects of this invention are as follows:

[0031] 1. The oil supply device designed in this invention has a simple structure and is easy to manufacture. It greatly saves processing costs while still being able to achieve complex oil supply functions.

[0032] 2. The oil supply device designed in this invention, compared with the traditional oil supply device, prevents bearing failure caused by insufficient oil supply to the edge of the bearing pad due to wear of the bearing pad edge, and improves the formation of oil film on the bearing pad during operation and improves the cooling effect of the bearing pad, reducing bearing pad problems and improving bearing applicability; at the same time, this invention can adapt to the stable oil supply of sliding bearings under the forward and reverse rotation conditions of a reversible gas turbine.

[0033] 3. The design method of this invention is reasonable, the design process is clear, and it is highly instructive, which greatly improves the efficiency of the oil supply device for the sliding bearing pads of a reversible gas turbine.

[0034] 4. This invention is the first application of this technology in the design of reversible gas turbine sliding bearings in China, and the results are summarized during the process. It has very important reference value in the future design of gas turbine sliding bearings. Attached Figure Description

[0035] Figure 1 Diagram showing areas with insufficient oil supply from grooved oil supply to existing tile blocks and nozzles.

[0036] Figure 2 This is an overall structural diagram of the gas turbine sliding bearing pad oil supply device of the present invention;

[0037] Figure 3 This is a cross-sectional view of the gas turbine sliding bearing pad oil supply device of the present invention;

[0038] Figure 4 This is a three-dimensional model diagram of the oil supply device for the tile blocks of the present invention;

[0039] Figure 5 This is a diagram illustrating the oil supply route of the present invention.

[0040] Figure 6 This is a structural diagram of the fuel injector of the present invention;

[0041] Figure 7 This is a structural diagram of the oil supply isolation ring nozzle of the present invention;

[0042] Figure 8 This is a diagram showing the oil spray coverage area of ​​the nozzle of the present invention;

[0043] Figure 9 This is a flowchart of the present invention. Detailed Implementation

[0044] The present invention will now be further described with reference to the accompanying drawings.

[0045] This invention first achieves its function through its unique structural form, employing an oil supply isolation ring structure, such as... Figures 2-4 As shown, it mainly consists of four parts: a cage, a large nut, a pin, and a plug. By controlling the oil supply to the bearing, more thorough lubrication of the bearing is achieved, while significantly reducing the operating temperature of the bearing. This device has a simple structure, is easy to manufacture, and can form complex oil supply circuits, providing comprehensive oil supply functionality.

[0046] Secondly, a reversible gas turbine sliding bearing pad oil supply device, the working oil supply principle of which is as follows: Figure 5 As shown, the lubricating oil first enters the first oil supply pipe of the isolation ring through the oil inlet of the isolation ring, and then enters the annular oil chamber of the inner ring through the first oil supply pipe. The lubricating oil then enters the remaining 7 oil supply pipes through the annular chamber. Each oil supply pipe has oil spray nozzles evenly arranged on both sides along the radial direction, as shown in Figure 6. By adjusting the angle of the oil spray nozzles, the angle α and position dimension L of the oil spray holes on both sides of the oil supply pipe can be adjusted, such as... Figure 7 As shown, the lubricating oil on one side is directly sprayed into the oil inlet side of the bearing pad, directly participating in the formation of the oil film on the pad. This greatly improves the film stability of the bearing pad under start-up, shutdown, and complex alternating load operating environments. The lubricating oil from the other side's spray nozzle is sprayed directly onto the edge of the bearing pad and the oil film position at the oil outlet. This position is where the temperature of each bearing pad and oil film is the highest, which greatly improves the cooling effect of the bearing pad and significantly reduces the operating temperature of the gas turbine sliding bearing bearing pad. When the gas turbine reverses, the functions of the holes on the oil inlet and outlet sides of the bearing pad are reversed, ensuring uniform oil supply and sufficient cooling of the sliding bearing during forward and reverse rotation of the gas turbine. In common sliding bearings, oil supply methods such as nozzles and grooved bearing pads only place the nozzle or oil inlet in the middle of the oil inlet of the bearing pad. This leads to insufficient lubricating oil supply at the edges and corners of the bearing pad, making them prone to wear. Wear at the edges of the bearing pad leads to damage to the entire bearing pad casting and causes failure. Compared to traditional oil supply structures, the bearing inlet is equipped with oil spray nozzles along the radial direction, making oil film formation on the bearing more stable and reliable. Simultaneously, the bearing outlet is also equipped with direct cooling oil spray along the radial direction, greatly improving the bearing cooling effect and significantly reducing the bearing's operating temperature. This allows it to adapt to the high-temperature operating environment of gas turbines and meet the requirements of forward and reverse rotation.

[0047] Finally, a design method for a reversible gas turbine sliding bearing pad oil supply device is achieved through the following steps:

[0048] S1: Given the design input. Based on the spatial arrangement of the gas turbine sliding bearings and the dimensions of the gas turbine main shaft, give the maximum outer diameter D of the bearing pad oil supply device cage. O and the minimum inner diameter D of the large nut i .

[0049] S2: Determine the number of oil supply pipes, n. Based on the structural characteristics of the oil supply device, the number of oil supply pipes is equal to the number of sliding bearing pads.

[0050] S3: Determine the oil supply pipe diameter φ. To ensure the flow resistance in the lubricating oil pipeline, the oil supply pipe diameter φ should theoretically be as large as possible, but the oil supply pipe diameter is constrained by the following parameters.

[0051] Based on the wrap angle of the sliding bearing design parameters, the distance L0 between the two bearing pads can be determined. The following relationship exists between the distance between the bearing pads and the width B of the oil supply pipe:

[0052] L0=B+2δ (1)

[0053] φ=B-2t (2)

[0054] Where δ is the gap between the cage and the tile, usually 0.3mm≤δ≤0.5mm. This gap can ensure that the tile can swing freely in the cage and that the lubricating oil between the tiles can be discharged in time.

[0055] t is the wall thickness of the oil supply pipe, which is usually ≥3mm to ensure sufficient strength of the cage.

[0056] S4: Determine the nozzle positioning dimensions L and α. Based on the working principle of the oil supply device, theoretically, the orifice diameter should be aligned with the oil inlet and outlet flanges of the bearing. In the design, using a 3D model for positioning allows for accurate and rapid determination of the orifice's position and angle dimensions.

[0057] S5: Determine the nozzle diameter d and spacing L K To ensure the spray effect of the nozzle, the diameter of the nozzle orifice K is usually 0.7mm ≤ d ≤ 3mm.

[0058] The working angle of a typical orifice spray is greater than 60°. To ensure uniform and sufficient lubrication of the bearing along the oil inlet edge, the nozzle spacing follows the following relationship: Figure 8 As shown.

[0059] L L ≤2*S*tan30° (3)

[0060] Where S is the distance from the nozzle to the edge of the tile.

[0061] S6: After completing the above design, the lubricating oil flow rate of a reversible gas turbine sliding bearing pad oil supply device is calculated. The lubricating oil flow rate is adjusted by adjusting the nozzle diameter and the spacing between the oil injection holes to meet the design requirements of the sliding bearing.

[0062] S7: When machining a reversible gas turbine sliding bearing pad oil supply device, the orifice diameter d should be machined according to the design minimum value or with allowance. Before installation, a lubricating oil flow test should be performed to measure the flow rate and adjust the nozzle orifice diameter d to meet the design requirements.

[0063] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A design method for an oil supply device for sliding bearing pads of a reversible gas turbine, characterized in that, Includes the following steps: S1, given the design input; Based on the spatial arrangement of the gas turbine sliding bearings and the dimensions of the gas turbine main shaft, the maximum outer diameter of the bearing pad oil supply device cage is given. and the minimum inner diameter of the large nut ; S2, determine the number of oil supply pipes n; Based on the structural characteristics of the oil supply device, the number of oil supply pipes is equal to the number of sliding bearing pads; S3, Determine the oil supply pipe diameter ; The diameter of the oil supply pipe is constrained by the following parameters: The spacing between the two bearing blocks is determined based on the wrap angle of the sliding bearing design parameters. The following relationship exists between the spacing between the tiles and the width B of the oil supply pipe: in To maintain the gap between the frame and the tiles, This gap ensures that the tiles can swing freely in the cage while also ensuring that the lubricating oil between the tiles can be discharged in a timely manner. t represents the oil supply pipe wall thickness, to ensure sufficient strength of the cage. ; S4, Determine the nozzle positioning dimension L and ; According to the working principle of the oil supply device, the diameter direction of the orifice should be directly aligned with the oil inlet and outlet edge plates of the pad. In the design, the position and angle dimensions of the orifice can be accurately and quickly determined by using a three-dimensional model for positioning. S5, determine the nozzle diameter d and spacing. ; To ensure the spray effect of the nozzle, the nozzle diameter , When the working angle of the nozzle spray is greater than 60°, to ensure that the bearing blocks receive uniform and sufficient lubrication along the oil inlet edge, the nozzle spacing follows the following relationship: L k ≤2 S tan30° (3) Where S is the distance from the nozzle to the edge of the tile; S6. After completing the above design, calculate the lubricating oil flow rate and adjust the lubricating oil flow rate by adjusting the nozzle diameter and the spacing between the injection holes to meet the design requirements of the sliding bearing. S7, machining the oil supply device for the sliding bearing pads of the reversible gas turbine that conforms to the design.

2. The design method of a reversible gas turbine sliding bearing pad oil supply device according to claim 1, characterized in that, During the processing of S7, the diameter d should be processed according to the minimum design value or with allowance. Before installation, a lubricating oil flow test should be performed to measure the flow rate and adjust the nozzle diameter d to meet the design requirements.

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