A method for improving the working life of a turbine disk

Abstract

The application relates to a method for prolonging the service life of a turbine disc, and relates to the technical field of a turbine disc of an aero-engine. The method comprises the following steps: heating a first region of the turbine disc and heating a second region of the turbine disc; obtaining a first real-time temperature of the first region and a second real-time temperature of the second region; if the first real-time temperature reaches a first temperature threshold corresponding to the first region, stopping heating the first region; if the second real-time temperature reaches a second temperature threshold corresponding to the second region, stopping heating the second region; wherein the first temperature threshold and the second temperature threshold are different. Different temperatures are used to heat different regions of the turbine disc, so that controllable elastic-plastic deformation of the turbine disc occurs, the crack tip is blunted, the damage tolerance is improved, the fatigue life at the center hole of the turbine disc is prolonged, and the service life of the turbine disc is significantly prolonged.

Description

Technical Field

[0001] This application relates to the field of aero-engine turbine disk technology, and in particular to a method for improving the service life of turbine disks. Background Technology

[0002] The turbine disk of an aircraft engine is a core component of modern aircraft engines. It is propelled by high-temperature combustion gases in the engine combustion chamber, converting the thermal energy of the combustion gases into mechanical energy to drive the engine.

[0003] However, the turbine disk rotates at high speed during operation, generating a large centrifugal load that the turbine disk itself must bear. According to elastoplastic theory, the centrifugal load increases from the outer edge of the disk towards the inner edge along the radius. That is, the load is greater closer to the inner bore region of the turbine disk center, making the inner bore a weak point for fatigue fracture. Typically, failures of engine turbine disks during operation are due to fatigue fracture in the inner bore region of the disk center.

[0004] Therefore, how to extend the service life of the inner bore area of ​​the engine turbine disk core has become an urgent technical problem to be solved. Summary of the Invention

[0005] This application provides a method for improving the service life of a turbine disk, which can extend the fatigue life of the inner bore region of the engine turbine disk core.

[0006] This application discloses the following technical solution:

[0007] In a first aspect, this application discloses a method for improving the service life of a turbine disk, wherein the turbine disk has multiple different regions, the different regions including at least a first region and a second region, and the method includes:

[0008] The first region of the turbine disk is heated, and the second region of the turbine disk is heated;

[0009] Obtain the first real-time temperature of the first region and the second real-time temperature of the second region;

[0010] If the first real-time temperature reaches the first temperature threshold corresponding to the first region, then heating of the first region shall be stopped.

[0011] If the second real-time temperature reaches the second temperature threshold corresponding to the second region, then heating of the second region is stopped; wherein the first temperature threshold is different from the second temperature threshold.

[0012] Optionally, a first thermocouple is provided in the first region, and a second thermocouple is provided in the second region; the heating of the first region of the turbine disk includes:

[0013] The first region of the turbine disk is heated by supplying power to the first thermocouple;

[0014] Heating the second region of the turbine disk includes:

[0015] The second region of the turbine disk is heated by supplying power to the second thermocouple.

[0016] Optionally, the ratio of the heating power of the first thermocouple to that of the second thermocouple is the ratio of the first temperature threshold to the second temperature threshold.

[0017] Optionally, the method further includes:

[0018] The first area is insulated with the first temperature threshold, and the second area is insulated with the second temperature threshold.

[0019] Optionally, the surface of the turbine disk is decorated with speckle patterns, and the method further includes:

[0020] Rotate the turbine disk;

[0021] Obtain the displacement of the speckle as the turbine disk rotates;

[0022] Based on the displacement of the speckle, the strain condition of the inner bore region of the turbine disk's center is obtained.

[0023] Optionally, obtaining the displacement of the speckle as the turbine disk rotates includes:

[0024] The displacement of the speckle pattern is obtained by capturing images of the rotating turbine disk using a high-speed camera.

[0025] Optionally, the method further includes:

[0026] If the strain in the inner bore region of the turbine disk reaches a preset strain threshold, the turbine disk is decelerated until it stops rotating.

[0027] Optionally, the method for creating the speckle pattern includes:

[0028] A speckled coating layer is created by spraying matte paint and developer onto the surface of the turbine disk using a speckled spraying device.

[0029] Optionally, obtaining the strain condition of the inner bore region of the turbine disk's center includes:

[0030] Based on TEMA software, the strain condition of the inner bore region of the turbine disk's center was obtained.

[0031] Optionally, before slowing down the turbine disk, the method further includes:

[0032] Maintain the rotational speed of the turbine disk such that the time for maintaining the rotational speed of the turbine disk reaches a preset time threshold.

[0033] Compared with the prior art, this application has the following beneficial effects:

[0034] This application provides a method for improving the service life of a turbine disk. The method utilizes pre-rotation technology to induce high-speed rotation of the turbine disk in an environment with a specific temperature gradient, while simultaneously employing digital speckle high-speed imaging technology to accurately monitor the strain field of the turbine disk in real time. Specifically, heating the turbine disk with a temperature gradient causes controllable elastoplastic deformation, which blunts crack tips, thereby increasing damage tolerance and improving the fatigue life at the center hole of the turbine disk, ultimately achieving a significant improvement in the service life of the turbine disk. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 A flowchart illustrating a method for improving the service life of a turbine disk, as provided in this application embodiment;

[0037] Figure 2 A schematic diagram of a turbine disk component provided in an embodiment of this application;

[0038] Figure 3 This is a schematic diagram of a high-speed rotating tester provided in an embodiment of this application;

[0039] Figure 4 This is a schematic diagram illustrating the connection between a turbine disk and a flexible shaft, provided as an embodiment of this application. Detailed Implementation

[0040] The term "comprising" and its variations as used herein are open-ended inclusions, meaning "including but not limited to". The term "based on" means "at least partially based on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments". Definitions of other terms will be given in the description below.

[0041] It should be noted that the concepts of "first" and "second" mentioned in this disclosure are used only to distinguish different devices, modules or units, and are not used to limit the order of functions performed by these devices, modules or units or their interdependencies.

[0042] It should be noted that the terms "a" and "a plurality of" used in this disclosure are illustrative rather than restrictive, and those skilled in the art should understand that, unless otherwise expressly indicated in the context, they should be understood as "one or more".

[0043] The technical terms used in this application will be introduced below.

[0044] Centrifugal force is a virtual force, a manifestation of inertia, that causes a rotating object to move away from its center of rotation.

[0045] Compressive stress is a negative force acting on the cross-section of an object, where the forces acting on both ends of the object are collinear and directed towards it. In other words, the centripetal force generated by the turbine disk during operation is compressive stress.

[0046] Tensile stress is the stress exerted on the cross-section of an object by two collinear forces acting in opposite directions. Therefore, it is positive. In other words, the centrifugal force generated by the turbine disk during operation is tensile stress.

[0047] Elastic-plastic theory refers to the property that when an object is subjected to an external force, it immediately undergoes full deformation, but when the external force is removed, only a portion of the deformation disappears immediately, while the remaining deformation never disappears on its own after the external force is removed.

[0048] The high-speed rotating test chamber is a primary testing device for evaluating the static and fatigue strength of disc-shaped structural components in mechanical equipment. It is used to address various strength and stiffness issues, such as static strength reserve and service life assessment. The testing device mainly includes a chamber, heating device, rotating motor, speed-increasing head, and additional functional systems.

[0049] The turbine disk of an aircraft engine refers to the hot-end component of the engine used to carry the blades. When the airflow impacts the blades, it drives the turbine disk to rotate. The turbine disk drives the shaft to rotate, which in turn drives the compressor to rotate at high speed. The high-speed rotation of the compressor drives the airflow. The high-pressure, high-speed airflow then impacts the blades, and the blades drive the turbine disk, thus creating a continuous cycle.

[0050] As mentioned above, the turbine disk of an aero-engine rotates at high speed during operation, thus generating a large centrifugal load, which the turbine disk itself must bear. According to the elastoplastic theory, the centrifugal load increases from the outer edge of the disk along the radius towards the inner edge. That is, the load is greater closer to the inner hole region of the turbine disk center. Therefore, the inner hole is prone to becoming a weak point for fatigue fracture of the turbine disk. Usually, the failure of engine turbine disks during operation is due to fatigue fracture in the inner hole region of the disk center.

[0051] To address the aforementioned deficiencies, this application provides a method for improving the service life of a turbine disk. This method utilizes pre-rotation technology to induce high-speed rotation of the turbine disk in an environment with a specific temperature gradient, while simultaneously employing digital speckle high-speed imaging technology to accurately monitor the strain field of the turbine disk in real time. Specifically, heating the turbine disk with a temperature gradient causes controllable elastoplastic deformation, which blunts crack tips, thereby increasing damage tolerance and improving the fatigue life at the center hole of the turbine disk, ultimately achieving a significant improvement in the service life of the turbine disk.

[0052] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0053] See Figure 1 The figure is a flowchart illustrating a method for improving the service life of a turbine disk according to an embodiment of this application. The method includes:

[0054] S101: Heating the turbine disk with a temperature gradient.

[0055] See Figure 2 This figure is a schematic diagram of a turbine disk component provided in an embodiment of this application. See also... Figure 3 This figure is a schematic diagram of a high-speed rotating tester provided in an embodiment of this application. When Figure 2 The turbine disk shown is connected to the tooling. Figure 3 The high-speed rotating test apparatus, as shown, heats different locations on the turbine disk with a temperature gradient on its flexible shaft. The high-speed rotating test apparatus is a primary testing device for evaluating the static and fatigue strength of disc-shaped structural components in mechanical equipment, used to address various strength and stiffness issues such as static strength reserve and service life assessment. Its testing apparatus mainly includes a chamber, heating device, rotating motor, speed-increasing head, and additional functional systems.

[0056] See Figure 4This figure is a schematic diagram of the connection between a turbine disk and a flexible shaft according to an embodiment of this application. In the figure, icon 1 represents the flexible shaft, icon 2 represents the speed increaser, icon 3 represents the tooling, and icon 4 represents the turbine disk. The flexible shaft is the connecting component, which can be connected to the drive spindle and then connected to the rotary tester via the drive spindle. The lower end of the flexible shaft is connected to the transition section of the tooling, thereby connecting it as a whole with the tooling and the workpiece.

[0057] It should be noted that the speckle pattern on the turbine disk surface is designed to allow the high-speed camera to monitor the strain of the turbine disk during rotation. In some specific embodiments, a speckle coating can be created by spraying matte paint and developer using a dedicated speckle spraying device. This method can effectively suppress the adverse effects of metallic reflections on the shooting process.

[0058] The purpose of heating to create a temperature gradient is to facilitate the generation of an annular plastic deformation zone in the inner hole area of ​​the turbine disk during rotation. The plastic deformation zone can easily blunt the crack tip, thereby improving damage tolerance and fatigue life.

[0059] In some specific implementations, see Figure 2 Thermocouples can be placed at temperature test points 1, 2, and 3 on the turbine disk. Test point 1 can be located in the first region of the turbine disk, test point 2 in the second region, and test point 3 in the third region. The first, second, and third regions of the turbine disk are heated by supplying power to the thermocouples. The first real-time temperature of the first region, the second real-time temperature of the second region, and the third real-time temperature of the third region are then acquired. If the first real-time temperature reaches the first temperature threshold corresponding to the first region, heating of the first region is stopped; if the second real-time temperature reaches the second temperature threshold corresponding to the second region, heating of the second region is stopped; and if the third real-time temperature reaches the third temperature threshold corresponding to the third region, heating of the third region is stopped. In some specific embodiments, the heating power ratio of the first, second, and third thermocouples is the same as the ratio of the first, second, and third temperature thresholds.

[0060] After the turbine disk has been heated as required, the thermocouple at the temperature test point can be removed to allow the turbine disk to rotate. It should be noted that other methods can also be used to heat the turbine disk; this application does not limit the specific heating method.

[0061] It should be noted that the first temperature threshold, the second temperature threshold, and the third temperature threshold are not the same. In some specific embodiments, the temperature test points 1, 2, and 3 of the turbine disk can be heated to 100℃±10℃, 480℃±10℃, and 650℃±10℃, respectively. That is, the first temperature threshold is set to 100℃±10℃, the second temperature threshold is set to 480℃±10℃, and the third temperature threshold is set to 650℃±10℃, thereby heating the turbine disk with a temperature gradient. It should be noted that this temperature value is usually the temperature of the turbine disk's working environment. The temperature test points can also be heated to other temperatures. For example, temperature test points 1, 2, and 3 can be heated to 150℃±10℃, 350℃±10℃, and 500℃±10℃, respectively. That is, the first temperature threshold is set to 150℃±10℃, the second temperature threshold is set to 350℃±10℃, and the third temperature threshold is set to 500℃±10℃. The heating temperatures of different temperature test points only need to have a temperature gradient. This application does not limit the specific heating temperature.

[0062] It should be noted that the above embodiment is described with three regions, but it can also be two regions, four regions, etc. The specific number of regions is not limited in this application.

[0063] S102: Determine whether the turbine disk has reached the required temperature.

[0064] In some specific implementations, it can be determined whether the turbine disk has reached the required temperature by measuring whether the temperatures at temperature test points 1, 2, and 3 of the turbine disk have reached the set temperature values.

[0065] If the turbine disk reaches the required temperature, proceed with steps S103 and thereafter; if the turbine disk does not reach the required temperature, continue heating the turbine disk with a temperature gradient, i.e., the steps in S101.

[0066] S103: Insulate the turbine disk.

[0067] If the turbine disk reaches the required temperature, it can be kept warm for a period of time. This is because the turbine disk itself has a certain thickness, and insulation ensures that the temperature is uniform from the inside out.

[0068] In some specific embodiments, the turbine disk can be kept warm for 2 hours. It should be noted that the turbine disk can also be kept warm for other durations, such as 1 hour or 3 hours. This application does not limit the specific duration of the warming.

[0069] S104: Increases the speed of the turbine disk.

[0070] Based on pre-rotation technology, the turbine disk component is gradually accelerated at a certain speed. Pre-rotation technology, also known as prestressing treatment or self-strengthening method, is a process for rotating turbine disks using a high-speed rotating tester.

[0071] It should be noted that the rotational speed during pre-rotation is usually higher than the actual operating speed, and the acceleration to speed up the turbine disk can be in the range of 20-30 r / s / min. This application does not limit the specific speed and acceleration.

[0072] S105: Monitors the strain of the turbine disk.

[0073] During the execution of action S104, which accelerates the turbine disk, the strain of the turbine disk is monitored in real time online. In some specific implementations, digital speckle high-speed imaging technology can be used, employing a high-speed camera in the imaging window of the high-speed rotating tester to monitor the strain of the turbine disk. Digital speckle high-speed imaging technology requires first drawing speckles on the turbine disk. When the turbine disk deforms due to high-speed rotation, the speckle points will undergo certain displacements. These displacement changes can be captured in real time by a high-speed camera. Combined with software such as TEMA, the results of displacement, velocity, and other parameters changing over time are displayed in predefined tables and charts through automatic tracking and analysis. This allows for the calculation of the strain field at different locations, enabling the fitting of the strain field and real-time online monitoring of the turbine disk's strain.

[0074] S106: Determine whether the strain in the inner hole region of the turbine disk center reaches the preset strain threshold.

[0075] In some specific embodiments, the preset strain threshold can be the fatigue life corresponding to different pre-tension amounts of the specimen, obtained by performing low-cycle fatigue tests on the material specimen. Different materials may correspond to different fatigue lives, so different preset strain thresholds can be set. For example, the optimal pre-tension amount corresponding to the fatigue life of the powder metallurgy turbine disk is between 1.5% and 5.0%, so the preset strain threshold can be set to 1.5% to 5.0%. It should be noted that this application does not limit the specific range of the preset strain threshold.

[0076] In some specific implementations, the target displacement can be tracked by a high-speed camera, and the results of displacement, velocity and other changes over time can be displayed in predefined tables and charts to determine the strain. Furthermore, the strain of the inner bore region of the turbine disk core can be displayed and updated in real time.

[0077] If the strain in the inner bore region of the turbine disk reaches the preset strain threshold, then execute S107 and subsequent steps; if the strain in the inner bore region of the turbine disk does not reach the preset strain threshold, then continue to execute S105, that is, monitor the strain of the turbine disk.

[0078] S107: Reduce the speed of the turbine disk until it stops.

[0079] Once the strain in the inner bore region of the turbine disk reaches a preset strain threshold, the turbine disk can be slowed down until it stops.

[0080] In some specific embodiments, the initial rotational speed of the high-temperature alloy turbine disk can be 10,000 r / min, and the high-temperature alloy turbine disk can be decelerated at an acceleration of 20 r / min / second. It should be noted that this application does not limit the specific initial rotational speed and the deceleration acceleration.

[0081] In some specific embodiments, the turbine disk rotation speed can be maintained until the strain in the inner bore region of the disk center reaches a preset strain threshold range. This current rotation speed is maintained for a preset time threshold before gradually reducing the turbine disk rotation speed until it stops. In one embodiment, the preset time threshold can be set to 3-5 minutes; that is, the current rotation speed is maintained for 3-5 minutes before gradually reducing the turbine disk rotation speed until it stops. The purpose of maintaining the load for 3-5 minutes is to allow for a certain amount of creep and stabilize the amount of plastic deformation. It should be noted that this application does not limit the specific duration of this hold.

[0082] According to the elastoplastic theory, the centrifugal force is greatest in the inner bore region of the turbine disk when it rotates. When the rotational speed reaches a certain point, and the centrifugal force exceeds the material's yield strength, plastic deformation occurs around the inner bore region of the disk. According to the elastoplastic theory, the centrifugal force is smaller at the rim. When the centrifugal force in the inner bore region of the disk reaches the material's yield strength, the centrifugal force at the rim is still relatively small and has not yet reached the material's yield strength, so elastic deformation occurs at the rim. That is, plastic deformation occurs around the central bore of the turbine disk, while elastic deformation occurs at the outer edge of the turbine disk. During unloading, the elastically deformed parts need to rebound, but the plastic deformation in the inner bore region of the disk restricts this rebound, causing distortion of the internal crystal lattice and resulting in uncoordinated deformation. This leads to residual compressive stress (i.e., centripetal force) in the disk's core area.

[0083] Under actual working conditions, the tensile stress (i.e. centrifugal force) in the inner hole region of the turbine disk is superimposed with its residual compressive stress (i.e. centripetal force), which can offset part of the working stress. This results in the actual working stress of the turbine disk being much smaller than the external load (centrifugal stress at the working speed), thus reducing the actual load and improving the fatigue life and working reliability of the turbine disk.

[0084] This application provides a method for improving the service life of a turbine disk. The method utilizes pre-rotation technology to induce high-speed rotation of the turbine disk in an environment with a specific temperature gradient, while simultaneously employing digital speckle high-speed imaging technology to accurately monitor the strain field of the turbine disk in real time. Specifically, heating the turbine disk with a temperature gradient causes controllable elastoplastic deformation, which blunts crack tips, thereby increasing damage tolerance and improving the fatigue life at the center hole of the turbine disk, ultimately achieving a significant improvement in the service life of the turbine disk.

[0085] It should be noted that although the operations are described in a specific order, this should not be interpreted as requiring these operations to be executed in the specific order shown or in a sequential order. In certain environments, multitasking and parallel processing may be advantageous.

[0086] It should be understood that the steps described in the method embodiments of this disclosure may be performed in different orders and / or in parallel. Furthermore, the method embodiments may include additional steps and / or omit the steps shown. The scope of this disclosure is not limited in this respect.

[0087] It should be noted that the various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, for the device and system embodiments, since they are basically similar to the method embodiments, the description is relatively simple, and the relevant parts can be referred to the description of the method embodiments. The device and system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components indicated as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of the solution in this embodiment according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0088] The above description is merely one specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for improving the service life of a turbine disk, characterized in that, The turbine disk has multiple distinct regions, including at least a first region and a second region. The surface of the turbine disk is decorated with speckle patterns. The method includes: The first region and the second region are heated with a temperature gradient, respectively; Obtain the first real-time temperature of the first region and the second real-time temperature of the second region; If the first real-time temperature reaches the first temperature threshold corresponding to the first region, then heating of the first region shall be stopped. If the second real-time temperature reaches the second temperature threshold corresponding to the second region, then heating of the second region is stopped; wherein, the first temperature threshold is different from the second temperature threshold. The first area is insulated with the first temperature threshold, and the second area is insulated with the second temperature threshold. After stopping heating and heat preservation of the first region and the second region, the turbine disk is rotated; Based on the displacement of the speckle when the turbine disk rotates, the strain condition of the inner bore region of the turbine disk center is determined; When the strain in the inner hole region of the turbine disk reaches a preset strain threshold, the turbine disk is decelerated until the duration of the deceleration reaches a preset time threshold, at which point the turbine disk is controlled to stop rotating; wherein, the preset strain threshold is a plastic strain threshold determined based on low-cycle fatigue tests of materials and used to introduce target residual compressive stress in the inner hole region.

2. The method according to claim 1, characterized in that, The first region is equipped with a first thermocouple, and the second region is equipped with a second thermocouple; the heating of the first region and the second region with a temperature gradient includes: By supplying power to the first thermocouple and the second thermocouple respectively, the first region and the second region are heated with a temperature gradient.

3. The method according to claim 2, characterized in that, The ratio of the heating power of the first thermocouple to that of the second thermocouple is the ratio of the first temperature threshold to the second temperature threshold.

4. The method according to claim 1, characterized in that, The displacement of the speckle when the turbine disk rotates is obtained in the following way: The displacement of the speckle pattern during the rotation of the turbine disk is obtained by capturing images of the rotating turbine disk using a high-speed camera.

5. The method according to claim 1, characterized in that, The method for producing the speckle pattern includes: A speckled coating layer is created by spraying matte paint and developer onto the surface of the turbine disk using a speckled spraying device.

6. The method according to claim 1, characterized in that, The determination of the strain condition in the inner bore region of the turbine disk center includes: Based on TEMA software, the strain condition of the inner bore region of the turbine disk's center was determined.

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