Lightweight noise reduction blade and blade lightweight noise reduction design method

Abstract

Provided is a blade lightweight noise reduction design method, which comprises the following steps: classifying a circle of blades in a circumferential direction according to load bearing capacity, and dividing the blades into at least three levels of load bearing blades according to the load bearing capacity from more to less; defining the first level of load bearing blades as the blades with the largest load bearing capacity, defining the third level of load bearing blades as the blades with the smallest load bearing capacity, and defining the second level of load bearing blades as the blades with the load bearing capacity between the first level of load bearing blades and the third level of load bearing blades; not adopting noise reduction design for the first level of load bearing blades, and adopting a local hollow structure for the second level of load bearing blades. The method can realize lightweight noise reduction design under the premise of ensuring the safety of the blades. Also provided is a lightweight noise reduction blade.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of aero-engines, in particular to the field of blade design. BACKGROUND

[0002] The existing fan design often adopts a fan OGV and shroud fusion design scheme. The OGV shroud and blade of the fusion design not only play a load bearing role, but also serve as an outlet guide function. With the further development of aero-engine material technology, basic research and design technology, various companies have launched more advanced new generation aero-engines, in which weight and noise are two important indicators of aero-engine advancement. Under the same thrust level, the lighter the weight, the more competitive and the higher the commercial potential; the lower the noise, the better the flying experience and the more comfortable the flying environment for air passengers.

[0003] However, safety and lightweight design are often contradictory opposites. Therefore, it is necessary to complete the lightweight and noise reduction design scheme of the blade under the premise of ensuring safety. SUMMARY

[0004] An object of the present application is to provide a lightweight and noise reduction design method for a blade.

[0005] Another object of the present application is to provide a lightweight and noise reduction blade.

[0006] To achieve the above object, a lightweight and noise reduction design method for a blade includes the following steps: S1. Classifying a circle of circumferentially distributed blades according to bearing weight, dividing at least into three levels of bearing blades according to the bearing weight from more to less, defining the first level of bearing blades as the blades with the most bearing weight, defining the third level of bearing blades as the blades with the least bearing weight, and defining the second level of bearing blades as the blades with bearing weight between the first and third levels of bearing blades; S2. Not adopting noise reduction design for the first level of bearing blades, and adopting a local hollow structure for the second level of bearing blades.

[0007] To achieve the above object, a lightweight and noise reduction blade is obtained by the above method, and the second level of bearing blades includes a blade body, a cover plate and a honeycomb structure. The blade body includes a reinforcing rib and a plurality of grooves divided by the reinforcing rib, the grooves include a leading edge groove and a trailing edge groove, and both are recessed towards the blade suction surface direction; the cover is used to close the grooves; and the honeycomb structure is arranged in the grooves.

[0008] In one or more embodiments, the blade includes a sound-absorbing plate for closing the leading edge groove to form a first chamber, the sound-absorbing plate and the cover plate form a second chamber, and the first and second chambers are both provided with the honeycomb structure.

[0009] In one or more embodiments, the sound attenuation plate and the cover plate are both provided with sound attenuation holes.

[0010] In one or more embodiments, the sound attenuation holes on the cover plate on the suction surface side of the blade are conical holes with a 45° conical angle.

[0011] In one or more embodiments, the honeycomb structure comprises a plurality of honeycomb units, each of which comprises a central honeycomb and a plurality of annular honeycombs surrounding the central honeycomb.

[0012] In one or more embodiments, the honeycomb unit comprises a sound attenuation hole provided on the cover plate and communicating with the central honeycomb, and a sound transmission hole connecting the central honeycomb and the annular honeycomb.

[0013] In one or more embodiments, the honeycomb structure is arranged to be bonded to the groove by an adhesive film.

[0014] In one or more embodiments, the cover plate is arranged to be bonded to the blade body and the honeycomb structure by an adhesive film.

[0015] In one or more embodiments, the second-stage blade further comprises an axial flange mounting edge at the blade rim plate and a radial connecting hole at the blade tip.

[0016] The above-mentioned blade lightweight noise reduction design method classifies the blades in detail, adopts local hollow design for blades with certain bearing capacity, realizes load transmission function, and realizes lightweight and noise reduction function of the blades through local hollow design and honeycomb structure, thereby solving the current design difficulty. BRIEF DESCRIPTION OF DRAWINGS

[0017] The above-mentioned and other features, properties and advantages of the present application will become more apparent through the following description with reference to the accompanying drawings and embodiments, in which:

[0018] Figure 1 is a schematic diagram of the classified blades;

[0019] Figure 2 is a component split diagram of the lightweight noise reduction blade;

[0020] Figure 3 is a schematic diagram of the leading edge groove, sound attenuation plate and leading edge honeycomb;

[0021] Figure 4 is a schematic diagram of the trailing edge groove and trailing edge honeycomb;

[0022] Figures 5A-5B is a schematic diagram of the connecting structure of the second-stage bearing;

[0023] Figure 6is a cross-sectional view of a lightweight noise-reducing blade;

[0024] Figure 7 is a schematic view of a honeycomb unit;

[0025] Figure 8 is a flowchart of a blade lightweight noise-reducing design method. DETAILED DESCRIPTION

[0026] The application will be further described below in conjunction with specific embodiments and drawings, and more details are set forth in the following description in order to fully understand the application, but the application can certainly be implemented in various other ways different from the description, and those skilled in the art can make similar generalizations and deductions according to actual application conditions without departing from the connotation of the application, so the protection scope of the application should not be limited by the content of the specific embodiments.

[0027] It should be noted that these and other subsequent drawings are only examples, and are not drawn according to the condition of the same scale, and should not be used as a limitation on the actual claimed protection scope of the application.

[0028] Lightweighting of the blade is generally achieved by structural optimization design and the like to reduce the weight. Blade noise reduction is generally achieved by aerodynamic blade design, structural design, material application and the like. For the whole blade, it generally needs to bear a sufficient load, such as Figure 1 The outlet guide vane (OGV) of the fan shown in FIG. 1 is generally used for the last stage of the stator member in the flow passage, and its main function is to change the outflow angle of the fluid in the flow passage, and it needs to play the role of load transmission.

[0029] In lightweight design, the use of lighter materials and structural features often means insufficient structural rigidity and insufficient strength margin, and the addition of new noise-absorbing materials and the like to the blade in noise reduction design also poses challenges to the overall safety of the blade.

[0030] Therefore, the blade lightweight noise-reducing design method of the present disclosure can carry out certain lightweight noise-reducing design under the premise of meeting safety, and specifically includes the following steps: S1. Classifying a circle of circumferentially distributed blades according to the load bearing capacity, dividing the blades into at least three levels according to the load bearing capacity from more to less, defining the first level of blades as the blades with the most load bearing capacity, defining the third level of blades as the blades with the least load bearing capacity, and defining the second level of blades as the blades with load bearing capacity between the first and third levels; S2. Not adopting noise reduction design for the first level of blades, and adopting local hollow structure for the second level of blades.

[0031] For example, the outlet guide vane of the fan shown in FIG. 1 is taken as an example to classify step S1. Figure 1 For example, the outlet guide vane of the fan shown in FIG. 1 is taken as an example to classify step S1.

[0032] The 48 fan OGV blades are divided into four levels according to the bearing load.

[0033] The first level bearing A is the two blades at 12 o'clock and 6 o'clock or the two blades closest to the position of 12 o'clock and 6 o'clock, which serves as the main fan OGV and provides the main rigidity and bearing, and is preferably made of TC4 titanium alloy.

[0034] The fourth level bearing C and the third level bearing D are alternately arranged in the circumferential direction, and the blade close to the blade of the second level bearing is the blade of the fourth level bearing, and the blade close to the blade of the first level bearing at 6 o'clock or the blade closest to the position of 6 o'clock is the blade of the third level bearing. In this way, the third level bearing includes 24 fan OGVs arranged at intervals, and is preferably made of aluminum alloy material; the fourth level bearing includes 22 fan OGVs arranged at intervals, and is preferably made of aluminum alloy material.

[0035] In this way, the fan OGV bearing types are classified in detail, and according to the different types of rigidity and bearing capacity, the material selection or structural design is used to meet the load transmission function.

[0036] As in some embodiments, the blade of the second level bearing is designed to include an axial flange mounting edge 10 at the blade edge plate and a radial connecting hole 20 at the blade tip. Each axial flange mounting edge 10 has two bolt connection holes for axial connection with the intermediate inner casing outer ring, and each radial connecting hole 20 is used for radial connection with the intermediate casing outer ring through a bolt, as shown in Figure 5A and 5B Such design makes the blade of the second level bearing can transmit various types of loads such as aerodynamic force, engine force and FBO load, and plays a load transmission function.

[0037] Since the second level bearing OGV blade needs to bear aerodynamic force, engine force and FBO load, the blade needs to have a certain rigidity. Therefore, the second level blade adopts a local hollow structure, as shown in Figures 2 to 7 which includes a blade body 30, a cover plate 40 and a honeycomb structure 50.

[0038] The blade body 30 includes a reinforcing rib 31 and a plurality of grooves 32 divided by the reinforcing rib 31, the grooves 32 including a leading edge groove 328 and a trailing edge groove 329, which are arranged to be recessed towards the blade suction surface direction, as shown in Figure 6 .

[0039] The cross-shaped reinforcing rib structure enhances the bending rigidity of the blade and improves the torsional rigidity of the blade, and in combination with the support honeycomb and the cover plate, ensures that the blade has sufficient rigidity.

[0040] As can be understood by those skilled in the art, the number of grooves and the shape of the reinforcing ribs can be changed according to the specific load requirements of the blade, and are not limited to the four grooves and the cross-shaped reinforcing rib structure described above.

[0041] The cover plate 40 is used to close the groove 32 to form a blade basin pressure surface. The honeycomb structure 50 is arranged in the groove 32, and the honeycomb structure located in the leading edge groove 328 is a leading edge honeycomb 51, and the honeycomb structure located in the trailing edge groove 329 is a trailing edge honeycomb 52.

[0042] Considering that the OGV blade leading edge has better noise reduction effect, under the premise of meeting the rigidity requirement, the leading edge honeycomb 51 located in the leading edge groove 328 adopts a high-noise-reduction double-cavity design. In some embodiments, the blade further includes a sound-absorbing plate 60 for closing the leading edge groove 328 to form a first cavity 321, and the sound-absorbing plate 60 and the cover plate 40 further form a second cavity 322, and the first cavity 321 and the second cavity 322 are both provided with the honeycomb structure 50. In this way, the leading edge honeycomb 51 includes four groups of honeycomb structures.

[0043] The sound-absorbing plate 60 is preferably made of resin-based composite materials, including but not limited to aramid, polyimide, S2 glass fiber, etc.

[0044] Considering that the blade trailing edge airfoil is relatively thin, under the premise of meeting the rigidity requirement, the trailing edge honeycomb 52 is designed to have a noise reduction single-cavity design, the cover plate 40 is filled with honeycomb structures in the corresponding area of the trailing edge groove 329 to form a layer of trailing edge honeycomb 52, and the cover plate 40 is provided with a sound-absorbing hole 45 corresponding to the trailing edge honeycomb 52.

[0045] Preferably, the sound-absorbing hole on the cover plate located on the pressure surface side of the blade, i.e., the suction side, is a conical hole with a cone angle of about 45° to absorb sound waves and reduce fan back noise.

[0046] The honeycomb structure 50 includes a plurality of honeycomb units 500, and each honeycomb unit 500 includes a central honeycomb 510 and a plurality of annular honeycombs 520 surrounding the central honeycomb 510. As shown in the embodiment shown in Figure 7 The central honeycomb 510 and the annular honeycomb 520 are both hexagonal structure honeycombs, and each 7 honeycombs form a sound-absorbing group.

[0047] The honeycomb unit 500 includes a sound hole 45 arranged on the cover plate 40 and communicating with the center honeycomb, and a sound transmission hole 46 connecting the center honeycomb and the annular honeycomb. In this way, the honeycomb unit 500 adopts a "one hole six reach" sound insulation design, and the middle honeycomb lattice corresponds to the sound hole on the cover plate, and the bottom 6 door-shaped sound transmission holes are connected with the 6 honeycombs. Through the honeycomb lattice and the sound insulation plate, the energy of the entering sound wave can be maximally and fastest dissipated, thereby improving the noise reduction effect.

[0048] The honeycomb structure 50 is arranged to be bonded on the groove 32 and the sound insulation plate 60 by an adhesive film, and the cover plate 40 is arranged to be bonded on the blade body 30 and the honeycomb structure 50 by an adhesive film, and after the bonding is completed, the heat pressing tank is entered for curing and forming.

[0049] Therefore, the above-mentioned blade lightweight noise reduction design method classifies the circumferential blades in detail, carries out lightweight noise reduction design of each blade according to the bearing characteristics, carries out lightweight noise reduction design under the premise of considering rigidity, adopts a local hollow structure, realizes the transmission of load, and meets the design requirements of lightweight noise reduction.

[0050] The present application uses specific words to describe the embodiments of the present application. As "one embodiment", "an embodiment", and / or "some embodiments" means a certain feature, structure or characteristic related to at least one embodiment of the present application. Therefore, it should be emphasized and noted that the "one embodiment" or "one embodiment" or "one alternative embodiment" mentioned in different positions in the specification does not necessarily refer to the same embodiment. In addition, some features, structures or characteristics in one or more embodiments of the present application can be properly combined.

[0051] In the description of the present application, it should be understood that the orientation words such as "front, back, up, down, left, right", "horizontal, vertical, perpendicular, horizontal" and "top, bottom" and the like indicate the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present application and simplifying the description, and in the absence of the opposite description, these orientation words do not indicate and imply that the indicated device or element must have a specific orientation or be constructed and operated in a specific orientation, therefore it cannot be understood as a limitation on the scope of protection of the present application; the orientation words "inner, outer" refer to the inner and outer of the contour of each component itself.

[0052] Although the present application is disclosed as above with the preferred embodiments, it is not intended to limit the present application, and any person skilled in the art can make possible changes and modifications without departing from the spirit and scope of the present application. Therefore, any modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application, which does not deviate from the technical scheme of the present application, falls within the protection scope defined by the claims of the present application.

Claims

1. A method for lightweighting and reducing noise in blades, characterized in that, The blades are OGV fan blades, and the process includes the following steps: S1. Classify the circumferentially distributed blades according to their load-bearing capacity. Based on the load-bearing capacity from highest to lowest, divide them into at least three levels of load-bearing blades. Define the first level of load-bearing blades as the blades with the highest load-bearing capacity, define the third level of load-bearing blades as the blades with the lowest load-bearing capacity, and define the second level of load-bearing blades as the blades with load-bearing capacity between the first level of load-bearing blades and the third level of load-bearing blades. The first level of load-bearing blades are the two blades at the 12 o'clock and 6 o'clock positions or the two blades closest to the 12 o'clock and 6 o'clock positions. The second level of load-bearing blades are the two circumferentially adjacent blades of the first level of load-bearing blades located at the 12 o'clock position or the blade closest to the 12 o'clock position. S2. No noise reduction design is adopted for the first-stage load-bearing blade, and the second-stage load-bearing blade adopts a lightweight noise-reducing blade structure. This structure is a partially hollow structure, including: The blade body includes reinforcing ribs and multiple grooves divided by the reinforcing ribs. The grooves include leading edge grooves and trailing edge grooves, both of which are recessed toward the suction surface of the blade. Cover plate, used to close the groove; A honeycomb structure is disposed within the groove; and A sound-absorbing plate is used to close the leading edge groove to form a first chamber. The sound-absorbing plate and the cover plate form a second chamber. The honeycomb structure is provided in both the first chamber and the second chamber.

2. The method as described in claim 1, characterized in that, Both the sound-absorbing plate and the cover plate are provided with sound-absorbing holes.

3. The method as described in claim 1, characterized in that, The silencing holes on the cover plate located on the suction side of the blade are tapered holes with a 45° cone angle.

4. The method as described in claim 1, characterized in that, The cellular structure includes multiple cellular cells, each of which includes a central cellular cell and multiple circumferential cellular cells surrounding the central cellular cell.

5. The method as described in claim 4, characterized in that, The cellular unit includes a sound-absorbing hole disposed on the cover plate and communicating with the central cellular unit, and a sound-transmitting hole connecting the central cellular unit and the circumferential cellular unit.

6. The method as described in claim 1, characterized in that, The honeycomb structure is configured to be bonded to the groove by an adhesive film.

7. The method as described in claim 1, characterized in that, The cover plate is configured to be bonded to the blade body and the honeycomb structure by means of an adhesive film.

8. The method as described in claim 1, characterized in that, The lightweight noise-reducing blade also includes an axial flange mounting edge located at the blade edge plate and a radial connection hole located at the blade tip.

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