Adjustable stator blade angle measurement method and aircraft engine

Abstract

The invention discloses an adjustable stator blade angle measurement method and an aircraft engine, comprising the following contents: measurement preparation, completing the assembly of a compressor to be measured, segmenting each blade channel based on equal annular area or equal mass flow, and taking the blade section profile at each segmentation as a measurement target; blade section profile measurement, measuring the blade section profile of each blade section around the circle; blade profile measurement data processing, obtaining a blade profile fitting curve; blade profile centerline angle calculation, taking the angle between the measured blade profile centerline and the theoretical blade profile centerline as the deviation angle, and obtaining the deviation angle distribution of the whole circle of blades; blade deviation angle data processing, expressing the dispersion degree of the blade deviation angle by calculation; judging whether the corresponding blade meets the design requirements according to the dispersion degree of the blade deviation angle.

Description

Technical Field

[0001] The present invention relates to the technical field of aircraft engines, and in particular, to a method for measuring an adjustable stator blade angle. In addition, the present invention also relates to an aircraft engine comprising the above-mentioned method for measuring an adjustable stator blade angle. Background Art

[0002] The front stage of the aircraft engine compressor often adopts a design with adjustable stator blade angle. By adjusting the opening of the stator blade angle, the flow area of ​​the front stage airflow channel can be adjusted to optimize the compressor surge margin. For example, in a 3-stage axial flow 1-stage centrifugal combination compressor, the compressor 0-stage guide vane and 1-stage stator blade are often designed to be adjustable in angle. The opening of the compressor adjustable stator blade angle is closely related to the surge margin and performance. Due to factors such as processing and manufacturing, assembly clearance, and design configuration, there will be a certain deviation between the actual angle of the compressor adjustable blade and the theoretical angle. If the deviation value exceeds a certain range, it will affect the compressor performance and surge margin. When assembling compressor components, it is necessary to grasp the deviation of the compressor adjustable stator blade angle. The allowable deviation value is related to the engine configuration and is usually required to be within 1 degree. If the deviation angle exceeds the allowable value, it is necessary to analyze the cause, replace the blades or certain parts, and reassemble to ensure that the deviation angle meets the design requirements.

[0003] At present, the commonly used methods for measuring the deviation angle of the adjustable stator blade of the compressor include white light measurement method, proprietary detection tool measurement method and other methods. The white light measurement method uses a white light projector to illuminate the blade, forms the projection shape of the stator blade on the white light projection screen, compares the projection shape of the processed blade with the theoretical blade profile coordinate scale, and obtains the characteristic parameters of the blade such as chord length, thickness, and installation angle. When a single blade has not been installed on the compressor, the white light measurement method can be used to obtain the blade profile characteristic parameters, but when the blade is installed on the compressor casing and becomes a component state, the white light measurement method cannot be applied due to the presence of obstructions. The proprietary tool measurement method requires the customization of a proprietary measurement tool, clamps the compressor stator blade on the tool, and obtains the blade profile characteristic parameters such as blade chord length and installation angle by comparing the processed blade with the theoretical mold blade. This method can be used when the blade is in a loose state and has not yet been installed on the compressor casing. When the blade is installed on the casing, the component state method cannot be applied due to the large size of the component and the presence of a large number of obstructions. Summary of the invention

[0004] The invention provides an adjustable stator blade angle measurement method and an aircraft engine, so as to solve the technical problem that the existing measurement method is not suitable for measuring the deviation angle of the adjustable stator blade of the compressor in the assembled state.

[0005] According to one aspect of the present invention, a method for measuring an adjustable stator blade angle is provided, comprising the following contents:

[0006] S1. Metering preparation: complete the assembly of the compressor to be tested, divide each blade channel based on equal annular area or equal mass flow, and use the blade cross-section profile at each division as the measurement target;

[0007] S2. Blade section profile measurement, measuring the blade section profile of each blade in a circle;

[0008] S3. Processing blade profile measurement data to obtain blade profile fitting curve;

[0009] S4. Calculate the blade profile midline angle, taking the angle between the measured blade profile midline and the theoretical blade profile midline as the deviation angle, and obtain the deviation angle distribution of the entire blade circle;

[0010] S5. Processing of blade deviation angle data, by calculating the dispersion of blade deviation angles;

[0011] S6. Determine whether the corresponding blade meets the design requirements according to the dispersion degree of the deviation angle of the blade.

[0012] As a further improvement of the above technical solution, step S1 includes:

[0013] S11. Number the entire circle of blades according to a regular pattern;

[0014] S12. The cutting section is rotated around the axis of the engine at a preset radial position to divide each blade channel and blade. The area or mass flow rate of each channel after division is the same, and the blade section profile after division is used as the measurement target.

[0015] As a further improvement of the above technical solution, step S2 includes:

[0016] The cross section at the split point is measured in a circle to obtain the blade profile coordinates of the measured cross section.

[0017] As a further improvement of the above technical solution, step S3 includes:

[0018] S31. Clean the measurement data points and remove obviously abnormal measurement data points;

[0019] S32. Select multiple coordinate points to perform initial fitting on the leading edge and the trailing edge of the blade profile to obtain an initial fitting curve;

[0020] S33. Iteratively optimize the coordinates of the initial fitting curve using an optimization algorithm to obtain a leading edge fitting curve and a trailing edge fitting curve;

[0021] S34. Make inscribed circles for the leading edge fitting curve and the trailing edge fitting curve respectively to obtain a leading edge fitting small circle and a trailing edge fitting small circle.

[0022] As a further improvement of the above technical solution, step S33 includes: the optimization algorithm adopts a genetic algorithm or a particle swarm algorithm, with the variation range of each initial control point as ±20% of the leading edge radius as the constraint boundary, and the minimum sum of the distances from each measurement coordinate point to the fitting curve as the optimization target.

[0023] As a further improvement of the above technical solution, step S4 includes:

[0024] S41. Draw inscribed circles on the leading edge and trailing edge of the theoretical blade, connect the centers of the inscribed circles of the theoretical blade to obtain the centerline of the theoretical blade, and connect the centers of the small fitting circles of the leading edge and the trailing edge to obtain the centerline of the measured blade;

[0025] S42. The included angle between the theoretical blade profile centerline and the measured blade profile centerline is taken as the deviation angle;

[0026] S43. Summarize the deviation angle distribution according to the blade numbering sequence of step S1.

[0027] As a further improvement of the above technical solution, step S5 includes:

[0028] S51. Calculate the mean and variance of the deviation angle;

[0029] S52. The arithmetic mean of the corresponding cross-sectional deviation angle means is taken as the comprehensive deviation angle, and the variance of the deviation angle is used to characterize the dispersion of the deviation angle.

[0030] As a further improvement of the above technical solution, step S7 is also included:

[0031] The blades whose deviation angle dispersion is greater than the set value shall be replaced and reassembled.

[0032] As a further improvement of the above technical solution, step S2 includes:

[0033] The blade profile is measured using the three-coordinate measurement method.

[0034] According to another aspect of the present invention, there is also provided an aircraft engine, which includes the above-mentioned adjustable stator blade angle measurement method.

[0035] The present invention has the following beneficial effects:

[0036] The metering method first divides each blade channel by equal annular area or equal mass flow, and takes the blade cross-section profile at each division as the metering target to represent the entire blade, thereby reducing the number of blade cross-sections that need to be measured in the blade height direction, reducing workload and improving efficiency; based on this, the blade cross-section profile is measured in a circle and the metering data is processed to obtain a fitting curve, and the angle between the midline of the metering blade profile fitting curve and the theoretical blade profile midline is used as the deviation angle to obtain the deviation angle of all metered blade cross-sections, and the degree of dispersion of the engine blade deviation angle is indicated by processing the blade deviation angle data, thereby finding out possible unqualified blades, re-disassembling and reassembling them and / or replacing them, and effectively eliminating possible safety hazards; the metering method simplifies the metering target, obtains the precise value of the blade deviation angle, and analyzes the deviation angle to determine the existing risks, based on which blades and related components with possible problems are eliminated to eliminate safety hazards, and the operation is simple and the application range is wide.

[0037] In addition to the above-described purposes, features and advantages, the present invention has other purposes, features and advantages. The present invention will be further described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0039] Figure 1 It is a schematic diagram of the structure of the adjustable guide vane of the compressor in the prior art;

[0040] Figure 2 is a flow chart of a metering method according to a preferred embodiment of the present invention;

[0041] Figure 3 is a schematic diagram of a theoretical blade profile of the first embodiment of the present invention;

[0042] Figure 4 Schematic diagram of the metering blade profile of the first embodiment of the present invention;

[0043] Figure 5 is an enlarged schematic diagram of the leading edge of the metering blade profile of the first embodiment of the present invention;

[0044] Figure 6 is an enlarged schematic diagram of the trailing edge of the metering blade profile of the first embodiment of the present invention;

[0045] Figure 7 Schematic diagram of the fitting curve of the leading edge of the metering blade profile of the first embodiment of the present invention;

[0046] Figure 8 Schematic diagram of the fitting curve of the trailing edge of the metering blade profile of the first embodiment of the present invention;

[0047] Fig. 9 Schematic diagram of the metered blade profile center line and the theoretical blade profile center line of the first embodiment of the present invention;

[0048] Fig.10 Schematic diagram of the angle between the metered blade profile centerline and the theoretical blade profile centerline according to the first embodiment of the present invention;

[0049] Fig.11 Schematic diagram of the division of the blade model measurement section according to the first embodiment of the present invention Figure 1 ;

[0050] Fig.12 Schematic diagram of the division of the blade model measurement section according to the first embodiment of the present invention Figure 2 ;

[0051] Fig.13 Schematic diagram of adjustable stator blades of a compressor according to Embodiment 1 of the present invention;

[0052] Fig.14 Schematic diagram of the deviation angle of the metering blade profile in the first embodiment of the present invention. DETAILED DESCRIPTION

[0053] The embodiments of the present invention are described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways as defined and covered below.

[0054] like Figures 1 to 14 As shown, the adjustable stator blade angle measurement method of this embodiment includes the following contents:

[0055] S1. Metering preparation: segment each blade channel based on equal annular area or equal mass flow, and use the blade cross-section profile at each segmentation point as the metering target;

[0056] S2. Blade section profile measurement, measuring the blade section profile of each blade in a circle;

[0057] S3. Processing blade profile measurement data to obtain blade profile fitting curve;

[0058] S4. Calculate the blade profile midline angle, taking the angle between the measured blade profile midline and the theoretical blade profile midline as the deviation angle, and obtain the deviation angle distribution of the entire blade circle;

[0059] S5. Processing of blade deviation angle data, by calculating the dispersion of blade deviation angles;

[0060] S6. Determine whether the corresponding blade meets the design requirements according to the dispersion degree of the deviation angle of the blade.

[0061] It can be understood that the present measurement method first divides each blade channel by equal annular area or equal mass flow, and takes the blade cross-section profile at each division as the measurement target to represent the entire blade, thereby reducing the number of blade sections to be measured in the blade height direction, reducing workload and improving efficiency; based on this, the blade cross-section profile is measured in a circle and the measurement data is processed to obtain a fitting curve, and the angle between the midline of the measured blade profile fitting curve and the theoretical blade profile midline is used as the deviation angle to obtain the deviation angle of all measured blade sections, and the degree of dispersion of the engine blade deviation angle is indicated by processing the blade deviation angle data, thereby finding out possible unqualified blades, re-disassembling and reassembling them and / or replacing them, effectively eliminating possible safety hazards; the present measurement method simplifies the measurement target, obtains the precise value of the blade deviation angle, analyzes the deviation angle and determines the risk, thereby realizing the measurement of the blade deviation angle in the assembled state, and thereby excluding blades and related components that may have problems, eliminating safety hazards, and is easy to operate and has a wide range of applications.

[0062] In this embodiment, step S1 includes:

[0063] S11. Number the entire circle of blades according to a regular pattern;

[0064] S12. The cutting section is rotated around the axis of the engine at a preset radial position to divide each blade channel and blade, and the area or mass flow rate of each channel after division is the same, and the blade section profile after division is used as the measurement target;

[0065] There is a certain amount of bending and twisting in the radial direction of the stator blades, and there may be axial and circumferential runout when the stator blades are assembled. The blade channel is divided by the equal annular area method, that is, the blade is divided into several blocks with the same flow area. The blade cross-sectional shape at each division represents the entire blade, thereby reducing the number of blade cross-sections that need to be measured along the blade height direction, which can better reflect the shape and position of the blade. At the same time, the metering workload is relatively small, reducing the measurement workload and improving work efficiency.

[0066] In this embodiment, step S2 includes:

[0067] The cross section at the split point is measured in a circle to obtain the blade profile coordinates of the measured cross section.

[0068] Among them, the three-coordinate metrology method can be used to measure the blade profile; specifically, the surface coordinate points of the stator blade are measured by a three-coordinate measuring instrument. After the blade is installed on the casing, the blade and the casing in the assembly state are placed on a three-coordinate turntable, and the blade profile coordinate points are scanned around the blade surface using a three-coordinate measuring needle to obtain the surface coordinate data points of the blade in the assembled state.

[0069] In this embodiment, step S3 includes:

[0070] S31. Clean the measurement data points and remove obviously abnormal measurement data points;

[0071] Due to the large curvature of the leading and trailing edges of the blade, the leading and trailing edge measurement data points often have discontinuities such as convexities or concavities. First, the measurement data points are cleaned to remove obviously abnormal measurement data points. Abnormal data points may be false points generated during measurement and do not really exist.

[0072] S32. Select multiple coordinate points to perform initial fitting on the leading edge and the trailing edge of the blade profile to obtain an initial fitting curve;

[0073] For example, the leading edge and the trailing edge are fitted using Besier curves using 6 points respectively to obtain the initial fitting curves;

[0074] S33. Iteratively optimize the coordinates of the initial fitting curve using an optimization algorithm to obtain a leading edge fitting curve and a trailing edge fitting curve;

[0075] Furthermore, the optimization algorithm adopts a genetic algorithm or a particle swarm algorithm, with the variation range of each initial control point being ±20% of the leading edge radius as the constraint boundary, and the optimization goal being the shortest sum of the distances from each measurement coordinate point to the fitting curve, and the leading edge fitting curve and the trailing edge fitting curve are obtained after iterative optimization; in the actual working process, there is a large amount of blade profile measurement data that needs to be processed, and by combining the optimization algorithm in the mathematical field with the technology in the aviation field, the data processing efficiency is greatly improved, and a fitting curve that conforms to the actual situation is obtained;

[0076] S34. Make inscribed circles for the leading edge fitting curve and the trailing edge fitting curve respectively to obtain a leading edge fitting small circle and a trailing edge fitting small circle.

[0077] In this embodiment, step S4 includes:

[0078] S41. Draw inscribed circles on the leading edge and trailing edge of the theoretical blade, connect the centers of the inscribed circles of the theoretical blade to get the center line of the theoretical blade, connect the centers of the small circles fitting the leading edge of the measured blade and the small circles fitting the trailing edge to get the center line of the measured blade; draw inscribed circles on the leading edge and trailing edge of the theoretical blade, refer to Figures 7 to 10 , connect the centers of the two inscribed circles of the theoretical blade profile to obtain the theoretical blade profile centerline L1, and connect the straight line between the center of the small circle A fitting the leading edge of the metered blade profile and the center of the small circle B fitting the trailing edge to obtain L2;

[0079] S42. The angle between the theoretical blade centerline and the metering blade centerline is obtained as the deviation angle; the angle between the theoretical blade centerline L1 and the metering blade centerline L2 is defined as the deviation angle α between the metering blade and the theoretical blade;

[0080] S43. Summarize the deviation angle distribution according to the order of blade numbers in step S1;

[0081] According to the experience of existing technology, the engine performance has a certain dispersion, which is caused by many factors. One of the important influencing factors is the deviation angle between the adjustable guide vane and the theoretical angle, which directly affects the parameters such as the engine surge margin and the engine power. The deviation angle of the adjustable guide vane is one of the parameters that need to be focused on during assembly. The deviation angle distribution is obtained and further processed through this step, and then the engine performance can be judged based on this and the corresponding applicability processing can be performed.

[0082] In this embodiment, step S5 includes:

[0083] S51. Calculate the mean and variance of the deviation angle;

[0084] S52. The arithmetic mean of the mean deviation angles of the corresponding cross sections is taken as the comprehensive deviation angle, and the variance of the deviation angle is used to characterize the dispersion of the deviation angle;

[0085] Among them, the comprehensive deviation angle is used to indicate the overall deviation degree of the blade. It is calculated by summing up the deviation angles of all the measured blades in a row of segmented sections and then dividing it by the number of blade sections, which is equivalent to the statistical mean deviation angle.

[0086] The variance of the deviation angle represents the degree of dispersion of the deviation angles. The larger the variance, the more dispersed the deviation angles are. The variance of the deviation angles of a row of blades is calculated with the mean as the center, which represents the degree of dispersion of the row of blades with the mean as the center.

[0087] The comprehensive deviation angle and deviation angle variance of the adjustable guide vanes of the assembled compressor are required to be within a certain range. In general, the comprehensive deviation angle is required to be less than ±1 degree and the deviation angle variance is required to be less than 0.2. The two values ​​are related to the engine size and characteristics and should be determined based on practical experience.

[0088] In this embodiment, step S7 is also included:

[0089] The blades whose deviation angle dispersion is greater than the set value shall be replaced and reassembled.

[0090] The comprehensive deviation angle and deviation angle variance of the entire circle of blades are obtained by calculation, and these two data values ​​are compared with the design requirements. If they exceed the allowable range, further analysis of the reasons is required to find out the blades whose deviations are greater than the set values, replace them and reassemble them, eliminate potential risks, and provide a technical basis and guidance for the safe and stable operation of the engine.

[0091] This measurement method has clear principles, is easy to operate, and has a wide range of applications. It can effectively analyze and identify possible unqualified blades and eliminate possible safety hazards.

[0092] On the other hand, the present embodiment further provides an aircraft engine, to which the above-mentioned adjustable stator blade angle measurement method is applied.

[0093] Embodiment 1

[0094] In this embodiment, the measurement method of the above preferred embodiment is applied.

[0095] Step S1 includes:

[0096] Select the engine compressor for assembly and number the stator blades according to a certain pattern. Fig.13 , numbering in clockwise or counterclockwise order; using Fig.11 The two cross-sectional position lines Q and P rotate along the engine axis, dividing each blade channel in turn, and dividing a single blade channel into three parts. Fig.12 Where m, n, and h respectively represent the three passage areas or mass flow rates, ensuring that the three passages have the same area or mass flow rate. The blade shape at two or three divisions represents the entire blade. Measuring the blade shape at two locations along the blade height direction can better reflect the shape and position of the blade. At the same time, the measurement workload is relatively small, which reduces the number of blade sections that need to be measured along the blade height direction, reduces the measurement workload, and improves work efficiency.

[0097] Step S2 includes:

[0098] Select the Q and P section blade profiles for circle measurement to obtain the Q and P section blade profile coordinate points;

[0099] Since the curvature of the leading and trailing edges of the blade is large, the leading and trailing edge measurement data points often have discontinuities such as convexities or concavities, and need to be processed in step S3;

[0100] Step S5 includes:

[0101] Process the deviation angles of the Q and P section metering blade profiles corresponding to each blade in the order of blade numbers to obtain the distribution of the deviation angles of the entire circle of blades. Fig.14 , the deviation values ​​of blades No. 1, No. 2, No. 3, No. 16, No. 17, and No. 18 are small, because they are close to the adjustable blade driving point, the blades are basically not deformed, and the blade deviation value is the smallest; the deviation angle values ​​of blades No. 9, No. 10, No. 11, and No. 12 are large, because they are farthest from the driving point, the blade deformation is large, and the blade angle deviation value is large;

[0102] Calculate the mean and variance of the deviation angle of the Q and P sections of each blade, define the arithmetic mean of the deviation angles of the Q and P sections corresponding to the entire circle of blades as the comprehensive deviation angle of the adjustable guide vane of this level, the comprehensive deviation angle represents the overall deviation degree of the blade, and the variance of the deviation angle represents the dispersion degree of the deviation angles. The larger the variance, the more dispersed the deviation angles are.

[0103] Finally, conclusions are drawn and processing is carried out based on the conclusions.

[0104] Practical application shows that this metrological verification method is feasible and reliable, and it can realize the measurement and analysis of the deviation value of the adjustable stator blade angle during the assembly of the compressor on the engine, thus eliminating potential safety risks.

[0105] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for measuring the angle of an adjustable stator blade, characterized in that: Includes the following: S1. Metering preparation: complete the assembly of the compressor to be tested, divide each blade channel based on equal annular area or equal mass flow, and use the blade cross-section profile at each division as the measurement target; S2. Blade section profile measurement, measuring the blade section profile of each blade in a circle; S31. Clean the measurement data points and remove obviously abnormal measurement data points; S32. Select multiple coordinate points to perform initial fitting on the leading edge and the trailing edge of the blade profile to obtain an initial fitting curve; S33. The coordinates of the initial fitting curve are iteratively optimized by using an optimization algorithm to obtain a leading edge fitting curve and a trailing edge fitting curve. The optimization algorithm uses a genetic algorithm or a particle swarm algorithm, with the variation range of each initial control point being ±20% of the leading edge radius as a constraint boundary, and the minimum sum of the distances from each measurement coordinate point to the fitting curve as the optimization target; S34. Make inscribed circles for the leading edge fitting curve and the trailing edge fitting curve, respectively, to obtain a leading edge fitting small circle and a trailing edge fitting small circle; S41. Draw inscribed circles on the leading edge and trailing edge of the theoretical blade, connect the centers of the inscribed circles of the theoretical blade to obtain the centerline of the theoretical blade, and connect the centers of the small fitting circles of the leading edge and the trailing edge to obtain the centerline of the measured blade; S42. The included angle between the theoretical blade profile centerline and the measured blade profile centerline is taken as the deviation angle; S43. Summarize the deviation angle distribution according to the preset order; S5. Processing of blade deviation angle data, by calculating the dispersion of blade deviation angles; S6. Determine whether the corresponding blade meets the design requirements according to the dispersion degree of the deviation angle of the blade.

2. The adjustable stator blade angle measurement method according to claim 1, characterized in that: Step S1 includes: S11. Number the entire circle of blades according to a regular pattern; S12. The cutting section is rotated around the axis of the engine at a preset radial position to divide each blade channel and blade. The area or mass flow rate of each channel after division is the same, and the blade section profile after division is used as the measurement target.

3. The adjustable stator blade angle measurement method according to claim 2, characterized in that: Step S2 includes: The cross section at the split point is measured in a circle to obtain the blade profile coordinates of the measured cross section.

4. The adjustable stator blade angle measurement method according to claim 1, characterized in that: Step S5 includes: S51. Calculate the mean and variance of the deviation angle; S52. The arithmetic mean of the corresponding cross-sectional deviation angle means is taken as the comprehensive deviation angle, and the variance of the deviation angle is used to characterize the dispersion of the deviation angle.

5. The adjustable stator blade angle measurement method according to any one of claims 1 to 4, characterized in that: The step S7 is also included: replacing and reassembling the blades whose deviation angle dispersion is greater than the set value.

6. The adjustable stator blade angle measurement method according to any one of claims 1 to 4, characterized in that: Step S2 includes: The blade profile is measured using the three-coordinate measurement method.

7. An aircraft engine, characterized in that: The invention relates to an adjustable stator blade angle measuring method according to any one of claims 1 to 6.

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