A rotor unbalance state evaluation method based on rotor free run phase angle

Abstract

The application discloses a rotor unbalance state evaluation method based on a rotor free stop phase angle, and is characterized in that the method comprises the following steps: step S1: rotor phase marking based on an engine assembly process; step S2: monitoring an engine operation state, and continuously recording rotor free stop phases of multiple marking points based on the marked rotor phase; step S3: analyzing and counting a characteristic parameter alpha value of the multiple marking points based on the recorded rotor free stop phases; and step S4: evaluating a rotor unbalance state according to the analyzed characteristic parameter alpha value, and outputting an evaluation result.

Description

Technical Field

[0001] This invention relates to the field of rotor analysis, and more specifically to a method for evaluating rotor imbalance based on the rotor free-stop phase angle. Background Technology

[0002] Aero-engines have complex structures, leading to numerous reasons for excessive vibration. While excessive rotor imbalance is a common cause of vibration, test data alone cannot immediately pinpoint the cause when vibration is high. Even if increased rotor imbalance is the cause, reliable rotor data is still required. For dual-rotor turbofan engines, the imbalance data of the high-pressure rotor typically requires disassembly and measurement. While this method provides accurate rotor imbalance measurements, it lacks timeliness and cannot promptly assess the extent of the imbalance. Summary of the Invention

[0003] The following provides a brief overview of one or more aspects to offer a basic understanding of them. This overview is not an exhaustive summary of all conceived aspects, nor is it intended to identify key or decisive elements of all aspects, nor to define the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form to prepare for the more detailed descriptions that follow.

[0004] The purpose of this invention is to solve the above-mentioned problems and provide a rotor imbalance assessment method based on the rotor free-stop phase angle. This method can assess the rotor imbalance, especially the high-pressure rotor of aero-engines that cannot be dynamically balanced on-site, without removing the engine from the test bench or disassembling it. The method is simple, easy to operate, and has strong engineering application value.

[0005] The technical solution of this invention is as follows:

[0006] This invention provides a method for evaluating rotor imbalance based on the rotor free-stop phase angle, comprising the following steps:

[0007] Step S1: Based on the engine assembly process, perform rotor phase marking;

[0008] Step S2: Monitor the engine operating status and continuously record the rotor free stop phase at multiple marked points based on the marked rotor phase;

[0009] Step S3: Analyze the recorded rotor free-stop phase and statistically analyze the characteristic parameter α values ​​of multiple marked points;

[0010] Step S4: Evaluate the rotor imbalance state based on the analyzed characteristic parameter α value and output the evaluation results.

[0011] In an embodiment of the rotor unbalance state evaluation method based on the rotor free stop phase angle according to the present invention, the characteristic parameter α value is the phase distribution range of the statistically marked points, and the rotor unbalance state evaluation method based on the rotor free stop phase angle determines the magnitude of the current rotor unbalance amount according to the statistically obtained characteristic parameter α value.

[0012] In an embodiment of the rotor unbalance state evaluation method based on the rotor free stop phase angle according to the present invention, if the statistically obtained characteristic parameter α value is equal to 360°, it indicates that the rotor unbalance amount is small, and at this time, the rotor unbalance state is not evaluated; if the statistically obtained characteristic parameter α value is less than 360°, it indicates that the rotor unbalance amount is large, and at this time, the rotor unbalance state is evaluated.

[0013] In an embodiment of the rotor unbalance state evaluation method based on the rotor free stop phase angle according to the present invention, when the rotor unbalance state evaluation method based on the rotor free stop phase angle evaluates the rotor unbalance state, it is described by the following formula:

[0014] U = f(α)

[0015] ; where α represents the characteristic parameter value.

[0016] In an embodiment of the rotor unbalance state evaluation method based on the rotor free stop phase angle according to the present invention, the rotor unbalance state evaluation method based on the rotor free stop phase angle uses the static unbalance amount U to characterize the balance state of the rotor, and calculates the rotor unbalance amount through the static unbalance amount U. The formula is as follows:

[0017] U = mr

[0018] where m represents the equivalent mass of the rotor unbalance amount, and r represents the radius where the equivalent mass of the rotor unbalance amount is located.

[0019] In an embodiment of the rotor unbalance state evaluation method based on the rotor free stop phase angle according to the present invention, the rotor unbalance state evaluation method based on the rotor free stop phase angle uses the static unbalance amount U = mr to characterize the balance state of the rotor; where the maximum torque Mu generated by the static unbalance amount U = mrG, and then based on the maximum torque Mu = mrG and the minimum dynamic friction torque M0 during rotor operation, it is determined whether the static unbalance amount U affects the free stop angle of the rotor.

[0020] In an embodiment of the rotor unbalance state evaluation method based on the rotor free stop phase angle according to the present invention, if Mu < M0, the rotor unbalance amount does not affect the free stop angle of the rotor; if Mu > M0, the rotor unbalance amount affects the free stop angle of the rotor.

[0021] According to an embodiment of the rotor imbalance state assessment method based on the rotor free-stop phase angle of the present invention, when the rotor imbalance affects the rotor free-stop angle, the process of influence is described by the following formula: If Mu(θ) = mrGsinθ > M0, the rotor continues to rotate under the action of torque Mu. During the rotation, θ gradually decreases, causing Mu to gradually decrease as well. When Mu(θ) = mrGsinθ ≤ M0, the rotor stops rotating. Here, θ represents the angle between the imbalance and the direction of gravity.

[0022] The present invention also provides a computer-readable medium storing computer program code that, when executed by a processor, implements the method described above.

[0023] The present invention also provides a rotor imbalance state assessment device based on the rotor free-stop phase angle, comprising:

[0024] Memory, used to store instructions that can be executed by a processor; and

[0025] A processor for executing the instructions to implement the method described above.

[0026] Compared with existing technologies, this invention offers the following advantages: By analyzing the factors influencing the rotor's free-stalling phase angle and the impact of rotor imbalance on this phase angle, this invention proposes a rotor imbalance assessment method based on the rotor's free-stalling phase angle. It analyzes the relationship between the torque generated by the imbalance and the minimum dynamic friction torque of the rolling bearing to determine the characteristic parameter α of the rotor's free-stalling phase angle. Then, the rotor imbalance state is assessed based on the relationship between the statistical characteristic parameter α and the imbalance. This invention allows for the assessment of rotor imbalance without removing the aero-engine from its platform, without disassembling it, and even without relying on vibration signals. The method is simple, easy to operate, and has strong engineering application value. Attached Figure Description

[0027] The above-described features and advantages of the present invention will be better understood after reading the following detailed description of embodiments of the present disclosure in conjunction with the accompanying drawings. In the drawings, components are not necessarily drawn to scale, and components having similar related characteristics or features may have the same or similar reference numerals.

[0028] Figure 1 This is a flowchart illustrating an embodiment of the rotor imbalance state assessment method based on the rotor free-stop phase angle of the present invention.

[0029] Figure 2 This is a schematic diagram illustrating the structure of an embodiment of the aircraft engine rotor of the present invention.

[0030] Figure 3 This is a schematic diagram illustrating one embodiment of the rotor free rotation process of the present invention.

[0031] Figure 4 This is a schematic diagram illustrating a state of a smaller rotor balance of the present invention.

[0032] Figure 5 This is a schematic diagram illustrating a state of an embodiment of the present invention with a large rotor balance.

[0033] Figure 6 This is a schematic diagram illustrating an embodiment of the functional relationship between the characteristic parameter α and the unbalance quantity U of the present invention.

[0034] Figure 7 This is a schematic diagram illustrating an embodiment of the maximum torque generated by the imbalance of the present invention.

[0035] Figure 8 This is a schematic diagram illustrating an embodiment of the present invention in which the torque generated under gravity causes the rotor to rotate. Detailed Implementation

[0036] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are merely some examples or embodiments of this application. For those skilled in the art, these drawings can be applied to other similar scenarios without creative effort. Unless obvious from the context or otherwise specified, the same reference numerals in the drawings represent the same structures or operations.

[0037] As indicated in this application and claims, unless the context clearly indicates otherwise, the words "a," "an," "an," and / or "the" are not specifically singular and may include plural forms. Generally speaking, the terms "comprising" and "including" only indicate the inclusion of explicitly identified steps and elements, which do not constitute an exclusive list, and the method or apparatus may also include other steps or elements.

[0038] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of this application. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0039] In detailing the embodiments of the present invention, for ease of explanation, the cross-sectional views illustrating the device structure will be partially enlarged and not to scale. Furthermore, the schematic diagrams are merely examples and should not limit the scope of protection of the present invention. In actual fabrication, the three-dimensional spatial dimensions of length, width, and depth should be included.

[0040] In the description of this application, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is usually based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this application and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this application; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0041] This document discloses an embodiment of a rotor imbalance state assessment method based on the rotor free-stop phase angle. Figure 1 This is a flowchart illustrating an embodiment of the rotor imbalance state assessment method based on the rotor free-stop phase angle of the present invention. Please refer to... Figure 1 The following is a detailed explanation of each step in the rotor imbalance state assessment method based on the rotor free-stop phase angle.

[0042] Step S1: Based on the engine assembly process, perform rotor phase marking.

[0043] In this embodiment, to assess rotor imbalance without removing the engine from the platform, disassembling it, or even relying on vibration signals, phase marking is performed on a stage of rotor blades (or on the drum shaft) that are easily identifiable by borehole inspection (i.e., visually). The rotor structure primarily consists of fulcrumped rolling bearings, including rolling bearing 1, rolling bearing 2, rotor body 3, and rotor blades 3.1, with specific shapes and structures as follows... Figure 2 As shown.

[0044] Step S2: Monitor the engine operating status and continuously record the rotor free stop phase of multiple marked points based on the marked rotor phase.

[0045] In this embodiment, after the aero-engine is installed, the blade angle at the borehole location is monitored and recorded after each operation (i.e., the blade angle at the borehole location is recorded after each operation after the engine is installed, or automatically recorded by a vision recognition system), or automatically recorded by a vision recognition system. After the aero-engine stops fueling from idle speed, the rotor begins to freely decrease in speed. Figure 3 This is a schematic diagram illustrating an embodiment of the rotor free-rotation process of the present invention, as shown below. Figure 3 As shown, when the rotor begins its free-fall rotation, the idle speed is relatively high, and the rotor has a large rotational kinetic energy. This kinetic energy is mainly converted into the kinetic energy of the gas through the moving blades on the rotor at the beginning of the fall. Figure 3 This is shown as Zone I. In the final stage of free-fall rotation, the rotor's kinetic energy has significantly decreased. During this stage, the rotor's kinetic energy is mainly converted into frictional work by the rolling bearings, i.e. Figure 3 The area shown is zone II.

[0046] Suppose there is a marked point A on the rotor circumference. Due to the high-speed rotation of the rotor, the phase of point A at each stop is random. Further assuming the energy consumption is constant during the stop, the circumferential position of point A when the rotor comes to a free stop should also be random. In reality, the rotational speed at the time of oil cut-off also fluctuates (uncertainty), so theoretically, the phase of the rotor at free stop should be random. Therefore, to obtain an accurate free stop phase angle, it is necessary to continuously record the rotor free stop phase at multiple marked points based on the pre-marked rotor phase.

[0047] Step S3: Analyze the recorded rotor free-stop phase and statistically analyze the characteristic parameter α values ​​of multiple marked points.

[0048] In this embodiment, the characteristic parameter α is the phase distribution range of the statistical marker points, and the magnitude of the current rotor imbalance is determined based on the statistical characteristic parameter α. Figure 4 This is a schematic diagram illustrating a state where the rotor balance amount of the present invention is relatively small. Figure 5 This is a schematic diagram illustrating an embodiment of the present invention with a relatively large rotor balance. For example... Figure 4 and Figure 5 As shown, if the statistical characteristic parameter α is within the angular range, a value greater than 180° indicates a small rotor imbalance, and the assessed imbalance is at the "small" level. If the statistical characteristic parameter α is less than 180°, it indicates a large rotor imbalance, in which case a more specific assessment of the rotor imbalance is performed, and an assessment value for the imbalance is given.

[0049] Step S4: Evaluate the rotor imbalance state based on the analyzed characteristic parameter α value and output the evaluation results.

[0050] In this embodiment, if the statistical characteristic parameter α is within an angular range, and its value is less than 180°, the rotor imbalance is relatively large. This imbalance is described by the following formula: Figure 6 The functional relationship between the characteristic parameter α and the unbalance quantity U is shown below:

[0051] U=f(α)

[0052] like Figure 6 As shown, if α is 45°, the unbalance of the rotor can be relatively easily evaluated as U1 according to the specific form of f(α), or the range of the unbalance under a certain probability [U1d U1u] can be given, where U1d is the lower limit of the range and U1u is the upper limit of the range.

[0053] Specifically, in this embodiment, the minimum dynamic friction torque of the rotor's rolling bearing is set to M0. The friction torque of the rolling bearing is divided into the friction torque between the rolling elements and the inner ring, the friction torque between the rolling elements and the outer ring, the friction torque between the rolling elements and the cage, and the drag torque of the lubricant. The total friction torque of the rolling bearing is related to the load borne by the bearing, the bearing's structural form, and the characteristics of the lubricant. For the same aero-engine, during the short period before the rotor free-falls and stops, the load borne by the rolling bearing (rotor weight) is the same, and the bearing's structural form remains constant. The temperature and viscosity of the lubricant are also basically consistent. Therefore, the minimum dynamic friction torque of the rolling bearing, M0, can be considered approximately a constant.

[0054] During the process of rotor imbalance, there are both static imbalances and torque imbalances. Since torques are imbalances of equal magnitude and opposite direction, it is rare for only torque imbalance to occur without static imbalance. Generally, static imbalance occurs during the process of rotor losing its good balance. Therefore, this embodiment uses the static imbalance quantity U to characterize the rotor's balance state, and calculates the rotor's imbalance using the static imbalance quantity U, as shown in the following formula:

[0055] U = mr

[0056] Where m represents the equivalent mass of the rotor's unbalance, and r represents the radius of the area containing the equivalent mass of the rotor's unbalance.

[0057] Among them, the static imbalance U = mr on the rotor will produce a phenomenon such as under the action of gravity. Figure 7 The diagram shows a torque about the center of a circle. The maximum torque, Mu = mrG, is given. Let Uc be the critical static imbalance. The maximum torque Mu = mrG under gravity is given. When Mu < M0, the rotor imbalance does not affect the rotor's free stop angle. However, when Mu > M0, especially when Mu is much larger than M0, the rotor imbalance will severely affect the rotor's free stop angle. If Mu(θ) = mrGsinθ > M0, then under the action of Mu, the rotor's center point will be as follows... Figure 8 As shown, the rotor rotates towards the 6 o'clock position until θ decreases to the point where Mu(θ) = mrGsinθ > M0. That is, under the action of the frictional torque M0, the rotor's center point stops at a certain angle from the 6 o'clock position.

[0058] Therefore, when the rotor imbalance increases to a certain extent, the imbalance will change the random distribution of the rotor's free-spinning stop. Conversely, the rotor's imbalance state can be reflected by the statistical results of the rotor's free-spinning stop angle.

[0059] This specification also provides a computer-readable medium storing computer program code that, when executed by a processor, implements the rotor imbalance state assessment method based on the rotor free-stop phase angle as described above.

[0060] This specification also provides a rotor imbalance state evaluation method based on the rotor free-stop phase angle, including a processor-executable instruction memory and a processor for executing the instructions in the instruction memory to implement the rotor imbalance state evaluation method based on the rotor free-stop phase angle as described above.

[0061] The prior description of this disclosure is provided to enable any person skilled in the art to make or use this disclosure. Various modifications to this disclosure will be apparent to those skilled in the art, and the general principles defined herein may be applied to other variations without departing from the spirit or scope of this disclosure. Therefore, this disclosure is not intended to be limited to the examples and designs described herein, but should be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0062] Those skilled in the art will further appreciate that the various illustrative logic blocks, modules, circuits, and algorithm steps described in conjunction with the embodiments disclosed herein can be implemented as electronic hardware, computer software, or a combination of both. To clearly illustrate this interchangeability between hardware and software, the various illustrative components, blocks, modules, circuits, and steps are described above in a generalized manner in terms of their functionality. Whether such functionality is implemented as hardware or software depends on the specific application and the design constraints imposed on the overall system. Those skilled in the art may implement the described functionality in different ways for each specific application, but such implementation decisions should not be construed as departing from the scope of the invention.

[0063] The various illustrative logic blocks, modules, and circuits described in conjunction with the embodiments disclosed herein can be implemented or performed using a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. The general-purpose processor may be a microprocessor, but in alternatives, it may be any conventional processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors cooperating with a DSP core, or any other such configuration.

[0064] The steps of the methods or algorithms described in conjunction with the embodiments disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of both. The software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to a processor such that the processor can read and write information to / from the storage medium. In an alternative, the storage medium may be integrated into the processor. The processor and storage medium may reside in an ASIC. The ASIC may reside in a user terminal. In an alternative, the processor and storage medium may reside as discrete components in the user terminal.

[0065] In one or more exemplary embodiments, the described functionality may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software as a computer program product, the functionality may be stored or transmitted as one or more instructions or code on or through a computer-readable medium. A computer-readable medium includes both computer storage media and communication media, encompassing any medium that facilitates the transfer of a computer program from one location to another. A storage medium may be any available medium accessible to a computer. By way of example and not limitation, such a computer-readable medium may include RAM, ROM, EEPROM, CD-ROM or other optical disc storage, disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and is accessible to a computer. Any connection is also legitimately referred to as a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of a medium. As used in this article, disk and disc include compact discs (CDs), laser discs, optical discs, digital multi-purpose discs (DVDs), floppy disks, and Blu-ray discs. Disks typically reproduce data magnetically, while discs reproduce data optically using lasers. Combinations of these should also be included within the scope of computer-readable media.

Claims

1. A method for evaluating rotor imbalance based on the rotor free-stop phase angle, characterized in that, It includes the following steps: Step S1: Based on the engine assembly process, perform rotor phase marking; Step S2: Monitor the engine operating state and continuously record the rotor free-stop phase of multiple marked points based on the marked rotor phase; Step S3: Analyze and statistically calculate the characteristic parameter α value of multiple marked points based on the recorded rotor free-stop phase; Step S4: Evaluate the rotor imbalance state according to the analyzed characteristic parameter α value and output the evaluation result.

2. The rotor imbalance state assessment method based on the rotor free-stop phase angle according to claim 4, characterized in that, The characteristic parameter α value is a statistical parameter; wherein, the rotor imbalance state evaluation method based on the rotor free-stop phase angle determines the magnitude of the current rotor imbalance according to the statistically calculated characteristic parameter α value.

3. The rotor imbalance state assessment method based on the rotor free-stop phase angle according to claim 2, characterized in that, When the statistically calculated statistical parameter α is a range of a set of data, when α is greater than 180°, it indicates that the rotor imbalance is small and the evaluated imbalance is at the "small" level; if the statistically calculated characteristic parameter α value is less than 180°, it indicates that the rotor imbalance is large, and at this time, the rotor imbalance state can be evaluated based on the specific value of α to give a more detailed imbalance result.

4. The rotor imbalance state evaluation method based on the rotor free-stop phase angle according to claim 3, characterized in that, When evaluating the rotor imbalance state by the rotor imbalance state evaluation method based on the rotor free-stop phase angle, it is described by the following formula: U = f(α); where α represents the characteristic parameter value.

5. The rotor imbalance state assessment method based on the rotor free-stop phase angle according to claim 4, characterized in that, The rotor imbalance state evaluation method based on the rotor free-stop phase angle uses the static imbalance U to characterize the balance state of the rotor, and calculates the rotor imbalance through the static imbalance U. The formula is as follows: U = mr Where m represents the equivalent mass of the rotor imbalance, and r represents the radius where the equivalent mass of the rotor imbalance is located.

6. The rotor imbalance state assessment method based on the rotor free-stop phase angle according to claim 4, characterized in that, The rotor imbalance state evaluation method based on the rotor free-stop phase angle uses the static imbalance U = mr to characterize the balance state of the rotor; where the maximum torque Mu generated by the static imbalance U = mrG, and then based on the maximum torque Mu = mrG and the minimum dynamic friction torque M0 during rotor operation, it is judged whether the static imbalance U affects the free-stop angle of the rotor.

7. The rotor imbalance state assessment method based on the rotor free-stop phase angle according to claim 6, characterized in that, If Mu < M0, the rotor imbalance does not affect the free-stop angle of the rotor; if Mu > M0, the rotor imbalance affects the free-stop angle of the rotor.

8. The rotor imbalance state assessment method based on the rotor free-stop phase angle according to claim 7, characterized in that, When the rotor imbalance affects the free-stop angle of the rotor, the influence process is described by the following formula; where, if Mu(θ) = mrGsinθ > M0, it keeps rotating under the action of the torque Mu, and θ gradually becomes smaller during the rotation process, resulting in Mu also gradually becoming smaller; when Mu(θ) = mrGsinθ ≤ M0, the rotor stops rotating. Where θ represents the angle between the imbalance and the direction of gravity.

9. A computer-readable medium storing computer program code, characterized in that, The computer program code, when executed by a processor, implements the method according to any one of claims 18.

10. A rotor imbalance state assessment device based on the rotor free-stop phase angle, characterized in that, It includes: A memory for storing instructions executable by a processor; And A processor for executing the instructions to implement the method according to any one of claims 1-6.

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