Rotor blade tip profiling design method, rotor blade and gas compressor

Abstract

The rotor blade tip profiling design method comprises the following steps that a scraping and grinding coating is arranged on the side, facing a rotor blade, of a casing, a plurality of bosses are arranged at the blade tip of the rotor blade in the chord length direction, and all the bosses are scraped and ground with the casing in the initial state; the engine is operated, so that rotor blades are in a working state and are scraped and abraded with the casing; after the working state is finished, scraping and grinding data of the scraping and grinding coating in the chord length direction of the blade are obtained; and reversely designing the radial size of the rotor blade tip according to the scraping and grinding data. According to the method, on the basis of the relation between the blade tip shape and the blade tip gap, flexible, accurate and multi-point design and control can be reversely carried out on the gap in the chord length direction of the blade through the scraping and grinding data of the scraping and grinding coating. The invention further provides a rotor blade and a gas compressor.

Description

Technical Field

[0001] This invention relates to the field of rotor blades for aero engines, and more specifically to the field of rotor blade tip contouring. Background Technology

[0002] The compressor is one of the most important components of an aero-engine, and the design, testing, and control of blade tip clearance are crucial to compressor performance. Variations in blade tip clearance are typically caused by a coupling of factors such as blade and casing deformation, eccentricity, and bearing clearance. These factors are numerous and difficult to accurately simulate and calculate during the design process.

[0003] Chinese patent CN112343855 proposes a method for on-wing assessment of blade tip clearance in aero-engines. The method involves coating the inner surface of the casing with a wear-prone coating, and creating at least two grooves on the tip of at least one rotor blade. The depth of each groove is different from the depth of any other groove. At least two marker blocks are placed on the portion of the wear-prone coating facing the rotor blade, and the thickness of each marker block is different from the thickness of any other marker block. A monitoring device is inserted into the aero-engine through a probe and aligned with the area including the grooves on the blade tip and the marker blocks on the wear-prone coating to obtain an image of the area. When the blade tip clearance changes due to mutual scraping between the rotor blade and the casing during on-wing operation, the wear amount of the wear-prone coating and the blade tip can be quickly and easily determined by identifying the number of remaining marker blocks on the casing's wear-prone coating and the number of remaining grooves on the rotor blade tip. Simultaneously obtaining the number of remaining marker blocks on the wear-prone coating and the number of remaining grooves on the blade tip determines the amount of wear. This allows for easy and accurate acquisition of the change in blade tip clearance during on-wing operation.

[0004] When designing rotor blade airfoils, aerodynamic performance and strength requirements are usually the primary considerations. The rotor blade tip size is typically determined by a straight line or two straight lines at a point and an angle, making it impossible to accurately design the clearance along the chord length. This often leads to problems with inconsistent rotor blade tip deformation. If the rotor blade tip clearance is too small, there is a risk of scraping the inner wall of the casing, compromising safety. If the rotor blade tip clearance is too large, it may result in the compressor's efficiency and performance failing to meet standards. Summary of the Invention

[0005] This invention provides a rotor blade tip contouring design method based on the relationship between blade tip shape and blade tip clearance.

[0006] To achieve the above objectives, the rotor blade tip contouring design method includes the following steps:

[0007] A scraping coating is provided on the side of the casing facing the rotor blades, and multiple protrusions are provided at the blade tips along the chordal direction. Each of the protrusions scrapes against the casing in the initial state.

[0008] The engine is turned on, so that the rotor blades are in working condition and constantly scraping against the casing;

[0009] After the working state ends, acquire the scraping data of the scraping coating along the blade chord direction;

[0010] The radial dimensions of the rotor blade tip are designed in reverse based on the scraping data.

[0011] In one or more embodiments, the radial height of the boss is not greater than 0.5 mm.

[0012] In one or more embodiments, the engine is operated and brought to a cruising state.

[0013] In one or more embodiments, the rotor blade tip includes a reference radial dimension, and the scraping data is subtracted sequentially from the reference radial dimension along the blade chord direction to obtain the design radial dimension of the rotor blade tip along the blade chord direction.

[0014] In one or more embodiments, after obtaining the scraping data at each point along the blade chord length direction, a fitting method is used to obtain the scraping variation line of the scraping coating, and the blade tip shape is obtained using the scraping variation line.

[0015] In one or more embodiments, the thickness of the scraping coating ranges from 1 to 100 mm.

[0016] In one or more embodiments, the engine is kept in cruise mode for a period of time.

[0017] In one or more embodiments, 20 to 30 bosses are provided along the chordal direction.

[0018] Another object of the present invention is to provide a rotor blade obtained using the above-described rotor blade tip contour design method.

[0019] Another object of the present invention is to provide a compressor, characterized in that it includes the aforementioned rotor blades.

[0020] The above-mentioned rotor blade tip contouring design method is based on the relationship between blade tip shape and blade tip clearance. By setting a locally protruding coating on the rotor blade tip, the measured clearance of the rotor blade tip is obtained. Based on the scraping data of the coating, the clearance along the blade chord length direction can be flexibly, accurately, and multi-point designed and controlled in reverse, thereby adjusting the radial dimension of the rotor blade tip to control the blade tip clearance. Attached Figure Description

[0021] The above and other features, properties and advantages of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings and embodiments, wherein:

[0022] Figure 1This is a schematic diagram of the mating structure between the rotor blades and the casing;

[0023] Figure 2 This is a schematic diagram of the scraped coating and boss;

[0024] Figure 3 This is a schematic diagram of the coating after scraping;

[0025] Figure 4 The rotor blade tip shape was obtained by reverse engineering based on the scraping data;

[0026] Figure 5 This is a flowchart of the rotor blade tip contour design method;

[0027] Figure 6 This is a schematic diagram of the change line of the scraped coating and the shape of the blade tip obtained by the fitting method.

[0028] Symbol marking explanation

[0029] 11 Casing

[0030] 12. Scraping coating

[0031] 20 Rotor blades

[0032] 21 Leaf tip

[0033] 22 convex platform Detailed Implementation

[0034] The present invention will be further described below with reference to specific embodiments and accompanying drawings. More details are set forth in the following description in order to provide a full understanding of the present invention. However, the present invention can obviously be implemented in many other ways different from those described herein. Those skilled in the art can make similar extensions and derivations based on actual application situations without departing from the spirit of the present invention. Therefore, the scope of protection of the present invention should not be limited by the content of this specific embodiment.

[0035] It should be noted that these and other accompanying drawings are merely examples and are not drawn to scale, and should not be construed as limiting the scope of protection of the present invention.

[0036] An aero engine comprises major structures such as a fan, compressor, turbine, and combustion chamber. The fan draws in a large volume of air, while the compressor compresses the air drawn into the core, progressively increasing its pressure and temperature to achieve efficient combustion in the combustion chamber. The combustion chamber mixes the high-pressure air and fuel, igniting the fuel to produce high-temperature, high-pressure combustion gases. The turbine uses these gases to drive the fan and compressor, expelling the expanded airflow at high speed, generating thrust.

[0037] Blades are key components in aero engines. Blade tip clearance refers to the gap between the blade tip and the casing, which has a significant impact on engine performance.

[0038] Specifically, the radial clearance between the rotor blade tip and the casing of an aero-engine compressor has a significant impact on the compressor's aerodynamic performance parameters, especially efficiency and margin. If the rotor blade tip deformation is inconsistent, it can lead to significant differences in the tip clearance values ​​along the chord length of blades in the same stage, affecting compressor performance and safety, especially for blades with large radial dimensions and long chord lengths. For example, a 0.1 mm increase in the tip clearance of a high-pressure compressor rotor will result in an approximately 0.6% decrease in efficiency at the design speed.

[0039] When designing rotor blade airfoils, aerodynamic performance and strength requirements are usually the main considerations. However, the problem of inconsistent blade tip deformation often occurs, resulting in a large difference in the tip clearance value along the chord length of rotor blades of the same stage. This affects the performance and safety of the compressor, especially for blades with large radial dimensions and long chord lengths.

[0040] Currently, rotor blade tip dimensions are typically determined by a single point and an angle along a straight line or two straight lines, using experimental experience such as data from blade tip clearance sensors and high-pressure compressor efficiency data. However, blade tip clearance sensors are frequently damaged or have inaccurate measurements, resulting in insufficient precision in blade tip dimensions, particularly hindering flexible, accurate, and multi-point control of the clearance along the chord length. The "chord length direction" of a blade refers to the direction between its leading and trailing edges, which is roughly parallel to the direction of airflow.

[0041] To address this problem, this invention proposes a rotor blade tip contouring design method based on the relationship between blade tip clearance and blade tip shape. This method can effectively control the uniformity of blade tip clearance and provide flexible, accurate, and multi-point control of the clearance in the chordal direction.

[0042] Combination Figures 1 to 5 Understood, this method includes the following steps:

[0043] A scraping coating 12 is provided on the side of the casing 11 facing the rotor blades, and multiple bosses 22 are provided along the chord length direction at the blade tip 21 of the rotor blade 20. Each boss 22 scrapes against the casing 11 in the initial state.

[0044] The engine is turned on, so that the rotor blades 20 are in working condition;

[0045] After the working state ends, acquire the scraping data of the coating 12 along the blade chord direction;

[0046] The radial dimensions of the rotor blade tip are designed in reverse based on the scraping data.

[0047] The method described below will be illustrated using an integral bladed disk as the first embodiment. An integral bladed disk is a novel structural component designed to meet the requirements of high-performance aero engines, performing work on gas by rotating around a rotational axis. The integral bladed disk integrates the engine rotor blades and the disk into a single structure, used to fix and support the blades and to transmit power through rotation.

[0048] Because the blades of the integral bladed disk have a large radial dimension and a long chord length, along the chord length direction at the rotor blade tip 21, that is... Figures 1 to 3 Multiple local bosses 22 are set in the left and right directions as shown.

[0049] The radial height of the boss 22 is preferably no more than 0.5 mm, so as to control the blade tip clearance on the order of 0.1 mm.

[0050] The number of bosses 22 needs to be sufficient, for example, 20 to 30, to achieve multi-point control of blade tip clearance. Ensure that during the initial test, all local bosses at the blade tip can be scraped against the casing.

[0051] Run the engine until it reaches cruise control, and maintain cruise control for a period of time. The engine is at its most efficient state during cruise control, and the rotor blades are in operation, scraping against the casing for a period of time to obtain the scraped coating 12'.

[0052] After removal from the machine, the measured clearance at various positions along the blade tip chord length can be obtained based on the scraping condition of the casing coating. By comparing the measured clearances at various positions along the blade tip chord length, if the clearances differ significantly or vary unevenly, it indicates that the blade tip deformation is not coordinated. The blade tip clearance can be controlled by adjusting the radial dimension of the rotor blade tip.

[0053] For example, the amount of coating scraped off is greater in the middle of the rotor blade tip, and less on the sides. Figure 2 and Figure 3 As shown, the dotted line represents the shape of the coating 12' after scraping. This data allows for reverse adjustment of the rotor blade tip shape and size; for example, the radial dimension of the blade tip can be controlled to be smaller where the scraping amount is larger, and larger where the scraping amount is smaller, to obtain the desired result. Figure 4 The design shown is blade tip 21'.

[0054] In some embodiments, the rotor blade tip includes a reference radial dimension, which is then subtracted sequentially from the scraping data along the blade chord length direction to quickly obtain the accurate design radial dimension of the rotor blade tip along the blade chord length direction.

[0055] The above method is based on the relationship between the blade tip shape and the blade tip gap. By scraping the coating data, it can flexibly, accurately and multi-pointly design and control the gap along the blade chord length. It can also obtain the blade tip shape through multi-point fitting, and the control accuracy can reach 0.1mm.

[0056] The second embodiment is described below. In this embodiment, the rotor blades and the impeller are separate structures. For example, the rotor blades are detachably connected to the impeller via tenons and mortises. This embodiment uses the component reference numerals and some content from the previous embodiments, where the same reference numerals are used to represent the same or similar components, and descriptions of the same technical content are selectively omitted. For explanations of the omitted parts, please refer to the previous embodiments; they will not be repeated here.

[0057] First, a scraping coating 12 is provided on the side of the casing 11 facing the rotor blade 20, and multiple protrusions 22 are designed at the blade tip 21 of the rotor blade to ensure that the local protrusions at the blade tip can be scraped onto the casing 11 during the first test.

[0058] The radial height of the boss should not exceed 0.5 mm to achieve the purpose of controlling the blade tip clearance at the order of 0.1 mm. A sufficient number of bosses are required, for example, 20 to 30 along the chord length, to achieve multi-point control of the blade tip clearance.

[0059] When first put into operation, the engine runs at cruise mode, where its efficiency is at its peak. It remains at cruise mode for a period of time, during which the rotor blades are engaged and continuously scrape against the casing.

[0060] After the machine is removed from the platform, the measured clearance at various positions along the tip chord direction in hot condition is obtained based on the scraping condition of the casing coating.

[0061] like Figure 6 As shown, after obtaining the scraping data at various points along the blade chord length, the scraping variation line A of the scraped coating is obtained through multi-point fitting, and then the designed blade tip shape B is obtained through reverse symmetry. Figure 6 M refers to the location of the inner side of the casing when no scraping occurs. When the rotor blade tip includes the reference radial dimension N, the reduction data L1 of the scraping coating is successively subtracted from the reference radial dimension along the blade chord direction to obtain the design radial dimension of the rotor blade tip along the blade chord direction.

[0062] Based on the above embodiments, the design dimensions at the blade tip can also be adjusted as needed according to the data on the reduction of the coating by scraping, and can be adjusted within a margin of ±0.5mm.

[0063] The above method is based on the relationship between blade tip shape and blade tip clearance. By scraping the coating data, it can solve the problem of inconsistent blade tip deformation of rotor blades, effectively control the uniformity of blade tip clearance, especially the uniformity along the chord direction, and flexibly, accurately, and multi-point control the clearance in the chord direction, with a control accuracy of 0.1 mm.

[0064] Based on the above introduction of the rotor blade tip contouring design method, it can also be connected to a rotor blade designed by the method and a compressor including the rotor blade.

[0065] 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.

[0066] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0067] Furthermore, this application uses specific terms to describe embodiments of the application. For example, "an embodiment," "one embodiment," and / or "some embodiments" refer to a particular feature, structure, or characteristic related to at least one embodiment of the application. Therefore, it should be emphasized and noted that "an embodiment," "one embodiment," or "an alternative embodiment" mentioned twice or more in different locations in this specification do not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of the application can be appropriately combined.

[0068] While the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Any variations and modifications can be made by those skilled in the art without departing from the spirit and scope of the invention. Therefore, any modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention, without departing from the scope of the invention, fall within the protection scope defined by the claims of the present invention.

Claims

1. A rotor blade tip contour design method, characterized in that, Includes the following steps: A scraping coating is provided on the side of the casing facing the rotor blades, and multiple bosses are provided at the blade tips along the chordal direction. Each of the bosses scrapes against the casing in the initial state. The engine is turned on, so that the rotor blades are in working condition and constantly scraping against the casing; After the working state ends, acquire the scraping data of the scraping coating along the blade chord direction; The radial dimensions of the rotor blade tip are designed in reverse based on the scraping data.

2. The rotor blade tip contouring design method as described in claim 1, characterized in that, The radial height of the boss is no greater than 0.5 mm.

3. The rotor blade tip contouring design method as described in claim 1, characterized in that, Start the engine and bring it to cruising speed.

4. The rotor blade tip contouring design method as described in claim 1, characterized in that, The rotor blade tip includes a reference radial dimension. The scraping data is subtracted from the reference radial dimension along the blade chord length direction to obtain the design radial dimension of the rotor blade tip along the blade chord length direction.

5. The rotor blade tip contouring design method as described in claim 1, characterized in that, After obtaining the scraping data at each point along the blade chord length, the scraping variation line of the scraped coating is obtained by fitting method, and the blade tip shape is obtained by using the scraping variation line.

6. The rotor blade tip contouring design method as described in claim 1, characterized in that, The thickness of the scraping coating ranges from 1 to 100 mm.

7. The rotor blade tip contouring design method as described in claim 1, characterized in that, Keep the engine in cruise mode for a period of time.

8. The rotor blade tip contouring design method as described in claim 1, characterized in that, The boss has 20 to 30 protrusions along the chord direction.

9. Rotor blades, characterized in that, Obtained using the rotor blade tip contouring design method as described in any one of claims 1-8.

10. A compressor, characterized in that, Includes the rotor blades as described in claim 9.

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