Design method for porous wave front edge bionic combined configuration blade wrapped by wire mesh

Abstract

The invention relates to the technical field of blade aerodynamic noise control, in particular to a design method of a metal wire mesh wrapped porous wave front bionic combined configuration blade. Firstly, a reference blade is divided into a porous area and a solid area. Secondly, carrying out wave front edge configuration design on the solid area, and extending the blade root and the blade tip in the extension direction to obtain a wave front edge configuration solid area; the porous area is subjected to wave front edge configuration design, a metal wire mesh shell is designed according to the wall face of the porous area subjected to bionic design, the blade root and the blade tip extend in the same direction, the metal wire mesh shell is filled with a porous medium material, and the porous area of the porous wave front edge bionic combined configuration is obtained; and finally, combining the porous area and the entity area together to complete the design. According to the porous-wave front edge bionic combined blade, the strength of the porous-wave structure can be improved through the metal wire net shell, the porous area and the solid area are well fixed together, and the fixing problem of the porous-wave front edge bionic combined blade is solved.

Description

Technical Field

[0001] The invention relates to the technical field of blade aerodynamic noise control, and in particular to a design method for a porous wave leading edge bionic combined configuration blade wrapped with a metal mesh. Background Art

[0002] With the rapid development of the aviation transportation industry, aircraft noise has become one of the important technical problems that the aviation industry is generally concerned about. Aircraft noise is closely related to flight safety, environmental protection, people's livelihood and other issues. The noise of aviation turbines has always been the focus of aircraft noise. Research on turbine noise is constantly being carried out. At present, the research on reducing turbine noise has entered a bottleneck period. Traditional noise control methods can no longer reduce noise further. The development of bionics has provided new ideas for noise control. According to the structure observed in the wings of owls, a "porous medium" bionic noise reduction configuration was proposed. According to the protruding characteristics of the leading edge of the pectoral fin of humpback whales, a "wave leading edge" bionic noise reduction configuration was proposed. A large number of research literature has proved that both bionic configurations can effectively suppress turbine noise.

[0003] It can be seen from the analysis of the existing technology that it is difficult to further reduce noise efficiently through a single bionic configuration. In the study of cylindrical airfoils, it was found that the wave leading edge is more effective in suppressing broadband noise, while the porous leading edge is more effective in suppressing single-tone noise. The porous wave leading edge has a significant suppressing effect on both single-tone noise and broadband noise. This shows that the combined design of porous medium and wave leading edge can retain the advantages of wave leading edge and porous medium in suppressing noise. Therefore, the porous-wave leading edge combined configuration is a bionic configuration with great noise reduction potential.

[0004] However, in the experimental research on the porous-wavy leading edge combination configuration, two problems that need to be solved were found: on the one hand, when the blade thickness is thin and the wave leading edge crest is relatively sharp, the strength of the porous wavy leading edge will be reduced. When the fan is blown in the experiment, it will cause deformation of the porous-wavy leading edge configuration; on the other hand, during the processing and manufacturing of the porous-wavy leading edge blade, due to the presence of porous media, the porous medium area needs to be processed separately from the other parts of the blade, which faces the problem of combining the porous medium and the solid part. If they are directly glued together, the aerodynamic performance of the blade will be damaged, and the strength of the glue cannot be guaranteed.

[0005] Therefore, in order to solve the two practical problems faced by the porous-wave leading edge combined bionic blade, the present invention proposes a design method for a porous wavy leading edge bionic combined configuration blade wrapped with a metal mesh. Summary of the invention

[0006] The purpose of the present invention is to avoid the shortcomings of the prior art and provide a design method for a porous wavy leading edge bionic combination configuration blade wrapped by a metal mesh, so as to solve the problems faced by the porous-wavy leading edge combination bionic blade in the experiment through the porous wavy leading edge combination configuration wrapped by a metal mesh.

[0007] To achieve the above object, the technical solution adopted by the present invention is: a method for designing a porous wave leading edge bionic combined configuration blade wrapped with a metal wire mesh, which is characterized by comprising the following steps:

[0008] Step 1: Divide the blade into porous area and solid area;

[0009] Step 2: Design the wave leading edge of the solid area, and extend the blade root and blade tip outward along the span direction according to the blade profile to obtain a fixed area for fixing the blade, and obtain the final wave leading edge solid area;

[0010] Step 3: Design the leading edge of the porous area into a wave leading edge, and match the trailing edge of the porous area with the wave leading edge of the solid area designed in the second step to obtain the wall shape of the porous area. According to the wall shape of the porous area, a metal mesh shell is made, and the porous medium material is filled in the middle area of ​​the metal mesh shell. Similarly, the blade root and the blade tip are extended outward along the span direction. The extended part is solid and used to fix the blade, so as to obtain the porous area of ​​the final porous wave leading edge bionic combination configuration;

[0011] Step 4: Combine the wave leading edge solid area obtained in the second step and the porous area of ​​the porous wave leading edge bionic combination configuration obtained in the third step to obtain a porous wave leading edge bionic combination configuration blade wrapped with a metal mesh.

[0012] Furthermore, in the first step, the blade is divided into a porous area and a solid area, and the segmentation method specifically includes the following steps:

[0013] (1) Select a reference blade and obtain the average chord length C of the blade. Divide the blade into two parts at a distance of 0.35° from the leading edge. The area from the leading edge to 0.35° is the porous area, and the area from 0.35° to the trailing edge is the solid area.

[0014] (2) In order to reduce the loss of aerodynamic performance of the blade, the solid part is streamlined at the 0.35C position, so the leading edge of the solid area is extended forward by 0.10C. In order to ensure that the blades are finally combined together, the trailing edge of the porous area needs to be consistent with the leading edge of the solid area.

[0015] Furthermore, in the second step, the wave leading edge design is performed on the solid area, which specifically includes the following steps:

[0016] (1) According to the existing wave front design technology, the wave front configuration is designed for the front edge of the solid area, and a sine function is selected to generate the wave front. The amplitude of the wave front is selected as 0.2C and the wavelength is 0.1C, and the main part of the solid area of ​​the wave front is obtained;

[0017] (2) According to the contours of the blade root and blade tip of the solid part after the wave leading edge is generated, the extension direction is extended outward by 0.1C to obtain a fixed area for fixing the blade, thereby obtaining the final wave leading edge solid area.

[0018] Furthermore, the design of the porous area in the third step mainly includes three parts: a metal mesh shell, a porous medium and a fixing device, and specifically includes the following steps:

[0019] (1) According to the wave front configuration design method used in the second step, the wave configuration of the front of the porous area is designed, and the sine function is selected to generate the wave front. The amplitude of the wave front is 0.2C and the wavelength is 0.1C, and the wave front configuration of the porous medium is obtained;

[0020] (2) The trailing edge of the porous region and the internal wall connected to it need to be consistent with the leading edge of the solid region. The trailing edge of the porous region has the same wave configuration as the leading edge of the solid region.

[0021] (3) Designing a metal mesh shell based on the shape of the wave leading edge of the porous region obtained in step (1) and the external wall connected thereto, and the wave trailing edge of the porous region obtained in step (2) and the internal wall connected thereto. The metal mesh shell is divided into two parts, namely, a front metal mesh and a rear metal mesh. The metal mesh shell is extended outward by 0.1° according to the contours of the blade tip and the blade root. The extended part is a solid body and is used to fix the blade.

[0022] (4) According to the metal mesh shell of the porous area obtained in step (3), the internal space is filled with porous media, and the bionic porous wave front edge is designed to be wrapped by the metal mesh shell. The material properties of the porous medium can be selected and replaced according to personal needs. In the present invention, the bionic porous wave front edge is designed to be wrapped by the metal mesh shell, which is also convenient for replacing the porous medium material in the porous area during the experiment.

[0023] Furthermore, the method for designing a porous wavy leading edge bionic combination configuration blade wrapped with metal mesh in the fourth step specifically includes: combining the wave leading edge solid area in the second step and the porous area of ​​the porous wave bionic combination obtained in the third step to obtain the porous wavy leading edge bionic combination configuration blade wrapped with metal mesh proposed in the present invention.

[0024] Furthermore, the fixing of the blades refers to the specific fixing method of the blades, which requires designing a blade fixing baffle that matches the fixing area. According to the contour of the fixing area, a corresponding contour groove is opened on the baffle. During the experiment, the extended fixing area is matched with the groove in the fixing baffle, so that the porous area and the solid area of ​​the blade can be better fixed together.

[0025] The present invention adopts the above-mentioned technical scheme and has the following beneficial effects: the bionic fan based on the combination of porous medium and wave leading edge configuration provided by the present invention wraps the porous medium with a metal mesh shell, and the strength of the porous-wave configuration can be increased by the metal mesh shell, and the application of the metal mesh shell can facilitate the replacement of the porous medium. Through the fixing device extending along the span direction, the porous area and the solid area can be better fixed together, thereby solving the problem of fixing the porous-wave leading edge bionic combination blades. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a flow chart of the present invention;

[0027] Figure 2 is a schematic diagram of a reference blade involved in a specific implementation manner of the present invention;

[0028] Figure 3 A schematic diagram of dividing a blade into a porous area and a solid area according to the present invention;

[0029] Figure 4 This is a schematic diagram of the wave front edge design of the entity area of ​​the present invention;

[0030] Figure 5 A schematic diagram of the bionic combined configuration design of the porous wave leading edge wrapped by the metal wire mesh of the present invention;

[0031] Figure 6 A schematic diagram of the combination of the porous area and the solid area of ​​the bionic blade of the present invention;

[0032] Figure 7 A schematic diagram of a bionic leaf of the present invention;

[0033] Figure 8 A schematic diagram of a baffle used to fix the bionic blade of the present invention in an experiment;

[0034] Fig. 9 This is a schematic diagram of fixing the bionic blade of the present invention.

[0035] In the figure, 1, porous area; 2, solid area; 3, leading edge of porous area; 4, trailing edge of porous area; 5, leading edge of solid area; 6, fixing device; 7, wire mesh shell; 8, porous medium. DETAILED DESCRIPTION

[0036] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0037] In order to achieve the above object, the present invention provides the following specific implementation methods: Figure 1-Figure 9 As shown in the figure, the design method of the bionic composite blade with porous wave leading edge wrapped by metal mesh is as follows: Figure 1 The following steps are shown:

[0038] Step 1: Divide the blade into porous area 1 and solid area 2;

[0039] Step 2: Design the leading edge 5 of the solid area with a wave leading edge, extend the blade root and the blade tip outward, and design a fixing device 6 for fixing the blade in the experiment;

[0040] Step 3: Design the leading edge 3 of the porous area with a wave leading edge, match the trailing edge 4 of the porous area with the leading edge of the solid area 5, and the trailing edge of the porous area is the same as the wave leading edge of the solid area designed in the second step. According to the wall surface of the porous area, a metal mesh shell is made, and the middle area is filled with porous medium material. Similarly, the blade root and the blade tip are extended outward to fix the blade in the experiment;

[0041] Step 4: Combine the wave leading edge solid area obtained in the second step and the porous area of ​​the porous wave leading edge bionic combination obtained in the third step to obtain a wire mesh wrapped porous wave leading edge bionic combination configuration blade design method.

[0042] The method of dividing the blade into the porous area and the solid area specifically includes the following steps:

[0043] (1) Select a reference blade, such as Figure 2 As shown, the average chord length C of the blade is obtained, and the blade is divided into two parts at a distance of 0.35C from the leading edge, the leading edge to 0.35C is a porous area 1, and the distance from 0.35C to the trailing edge is a solid area 2;

[0044] (2) In order to reduce the loss of aerodynamic performance of the blade, the solid part 0.35C position is streamlined, so the leading edge 5 of the solid area is extended forward by 0.10C. In order for the blade to be finally combined together, the trailing edge 4 of the porous area and the leading edge 5 of the solid area need to be consistent. The final segmentation of the blade is as follows: Figure 3 shown.

[0045] In the second step, the wave front edge design is performed on the solid area 2, which specifically includes the following steps:

[0046] (1) According to the existing wave front design technology, the wave front configuration design is performed on the front edge 5 of the solid area, and a sine function is selected to generate the wave front. The amplitude of the wave front is selected as 0.2C and the wavelength is 0.1C, and the main part of the solid area of ​​the wave front is obtained;

[0047] (2) According to the contours of the root and tip of the solid part after the wave leading edge is generated, the extension direction is extended outward by 0.1C to generate a fixing device 6, which is used to fix the bionic blade in the experiment, and the final wave leading edge solid area is obtained as shown in Figure 4 shown.

[0048] The bionic design of the porous area in the third step mainly comprises three parts: a metal mesh shell, a porous medium and a fixing device, and specifically comprises the following steps:

[0049] (1) According to the wave front configuration design method used in the second step, the wave configuration of the porous area front 3 is designed, and a sine function is selected to generate the wave front. The amplitude of the wave front is 0.2C and the wavelength is 0.1C, and the wave front configuration of the porous medium is obtained;

[0050] (2) The trailing edge 4 of the porous region and the internal wall connected thereto need to be consistent with the leading edge of the solid region 2, and the trailing edge 4 of the porous region has the same wave configuration as the leading edge 5 of the solid region;

[0051] (3) The wave front edge of the porous region obtained in step (1) and the external wall connected thereto, as well as the wave trailing edge of the porous region obtained in step (2) and the internal wall connected thereto, are used to design a metal mesh shell 7, and the metal mesh shell 7 is divided into two parts, such as Figure 5 As shown in , it is divided into a front wire mesh and a rear wire mesh, and according to the contours of the blade tip and the blade root, it is extended outward by 0.1C, which is used to fix the bionic blade in the experiment;

[0052] (4) Based on the metal mesh shell 7 of the porous area obtained in step (3), the internal space is filled with a porous medium 8. The material properties of the porous medium can be selected and replaced according to personal needs. The present invention designs the bionic porous wave leading edge to be wrapped in a metal mesh shell, which is also convenient for replacing the porous medium material in the porous area during the experiment.

[0053] The method for designing a porous wave leading edge bionic combination blade wrapped with a metal mesh in the fourth step specifically includes: combining the wave leading edge solid area in the second step and the porous area of ​​the porous wave bionic combination obtained in the third step. The specific combination method is as follows: Figure 6 As shown in Figure 7 The design method of the porous wavy leading edge bionic combined configuration blade wrapped with metal mesh is shown in the figure.

[0054] The specific fixing method of the blade in the experiment mentioned in the present invention is as follows Figure 8 and Fig. 9 As shown, it is necessary to design a fixed baffle that matches the fixing device of the bionic blade proposed in the present invention, and to open a corresponding contour groove on the baffle. During the experiment, the fixing device extended in the bionic blade design is matched with the groove in the fixed baffle, as shown in FIG. Figure 8 As shown in , the porous area and the solid area of ​​the bionic blade can be better fixed together.

[0055] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A design method for a porous wave leading edge bionic combined configuration blade wrapped with a metal wire mesh, characterized in that: The following steps are involved: Step 1: Divide the blade into porous area and solid area; Step 2: Design the wave leading edge of the solid area, and extend the blade root and blade tip outward along the span direction according to the blade profile to obtain a fixed area for fixing the blade, and obtain the final wave leading edge solid area; Step 3: Design the leading edge of the porous area into a wave leading edge, and match the trailing edge of the porous area with the wave leading edge of the solid area designed in the second step to obtain the wall shape of the porous area. According to the wall shape of the porous area, a metal mesh shell is made, and the porous medium material is filled in the middle area of ​​the metal mesh shell. Similarly, the blade root and the blade tip are extended outward along the span direction. The extended part is solid and used to fix the blade, so as to obtain the porous area of ​​the final porous wave leading edge bionic combination configuration; Step 4: Combine the wave leading edge solid area obtained in the second step and the porous area of ​​the porous wave leading edge bionic combination configuration obtained in the third step to obtain a porous wave leading edge bionic combination configuration blade wrapped with a metal mesh.

2. The method for designing a porous wave leading edge bionic combined configuration blade wrapped by a metal mesh as claimed in claim 1, characterized in that: In the first step, the blade is divided into a porous area and a solid area. The segmentation method specifically includes the following steps: (1) Select a reference blade and obtain the average chord length C of the blade. Divide the blade into two parts at a distance of 0.35° from the leading edge. The area from the leading edge to 0.35° is the porous area, and the area from 0.35° to the trailing edge is the solid area. (2) In order to reduce the loss of aerodynamic performance of the blade, the solid part is streamlined at the 0.35C position, so the leading edge of the solid area is extended forward by 0.10C. In order to ensure that the blades are finally combined together, the trailing edge of the porous area needs to be consistent with the leading edge of the solid area.

3. The method for designing a porous wave leading edge bionic combined configuration blade wrapped by a metal wire mesh as claimed in claim 1, characterized in that: In the second step, the wave front edge design is performed on the solid area, which specifically includes the following steps: (1) According to the existing wave front design technology, the wave front configuration is designed for the front edge of the solid area, and a sine function is selected to generate the wave front. The amplitude of the wave front is selected as 0.2C and the wavelength is 0.1C, and the main part of the solid area of ​​the wave front is obtained; (2) According to the contours of the blade root and blade tip of the solid part after the wave leading edge is generated, the extension direction is extended outward by 0.1C to obtain a fixed area for fixing the blade, thereby obtaining the final wave leading edge solid area.

4. The method for designing a porous wave leading edge bionic combined configuration blade wrapped by a metal wire mesh as claimed in claim 1, characterized in that: The design of the porous area in the third step mainly includes three parts: The wire mesh shell, the porous medium and the fixing device specifically include the following steps: (1) According to the wave front configuration design method used in the second step, the wave configuration of the front of the porous area is designed, and the sine function is selected to generate the wave front. The amplitude of the wave front is 0.2C and the wavelength is 0.1C, and the wave front configuration of the porous medium is obtained; (2) The trailing edge of the porous region and the internal wall connected to it need to be consistent with the leading edge of the solid region. The trailing edge of the porous region has the same wave configuration as the leading edge of the solid region. (3) Designing a metal mesh shell based on the shape of the wave leading edge of the porous region obtained in step (1) and the external wall connected thereto, and the wave trailing edge of the porous region obtained in step (2) and the internal wall connected thereto. The metal mesh shell is divided into two parts, namely, a front metal mesh and a rear metal mesh. The metal mesh shell is extended outward by 0.1° according to the contours of the blade tip and the blade root. The extended part is a solid body and is used to fix the blade. (4) According to the metal mesh shell of the porous area obtained in step (3), the inner space is filled with porous medium, and the leading edge of the bionic porous wave is designed to be wrapped by the metal mesh shell.

5. The method for designing a porous wave leading edge bionic combined configuration blade wrapped by a metal mesh as claimed in claim 1, characterized in that: The method for designing a porous wavy leading edge bionic combination configuration blade wrapped with metal mesh in the fourth step specifically includes: combining the wave leading edge solid area in the second step and the porous area of ​​the porous wave bionic combination obtained in the third step to obtain the porous wavy leading edge bionic combination configuration blade wrapped with metal mesh proposed in the present invention.

6. The method for designing a porous wave leading edge bionic combined configuration blade wrapped by a metal wire mesh as claimed in any one of claims 1 to 5, characterized in that: The fixing of the blades mentioned above refers to the specific fixing method of the blades. It is necessary to design a blade fixing baffle that matches the fixing area. According to the contour of the fixing area, a corresponding contour groove is opened on the baffle, and the extended fixing area is matched with the groove in the fixing baffle, that is, the porous area and the solid area of ​​the blade are fixed together.

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