Metal wire wrapped porous wave front biomimetic composite configuration blade design method

Abstract

This invention relates to the field of blade aerodynamic noise control technology, and more particularly to a design method for a porous wave-leading edge biomimetic composite blade with a wire mesh casing. First, a reference blade is divided into a porous region and a solid region. Next, the solid region is designed with a wave-leading edge configuration, extending from the blade root and tip to obtain the wave-leading edge configuration solid region. The porous region is then designed with a wave-leading edge configuration, and a wire mesh shell is designed based on the walls of the biomimetic porous region. Similarly, the blade root and tip are extended, and the wire mesh shell is filled with a porous medium material to obtain the porous region of the porous wave-leading edge biomimetic composite configuration. Finally, the porous region and the solid region are combined to complete the design. This invention can increase the strength of the porous-wave configuration through the wire mesh shell, effectively fixing the porous region and the solid region together, thus solving the fixation problem of the porous-wave-leading edge biomimetic composite blade.

Description

Technical Field

[0001] This invention relates to the field of blade aerodynamic noise control technology, and in particular to a design method for a porous wave leading edge biomimetic composite blade with a metal wire mesh wrapping. Background Technology

[0002] With the rapid development of the air transport industry, aircraft noise has become one of the most important technical challenges of widespread concern in the aviation sector. Aircraft noise is closely related to flight safety, environmental protection, and people's livelihoods. The noise of aircraft turbines has always been a key focus of aircraft noise research. Research on turbine noise is ongoing, but current efforts to reduce it have reached a bottleneck, as traditional noise control methods are no longer sufficient to further reduce noise. The development of bionics has provided new ideas for noise control. Based on the structure observed in owl wings, a "porous medium" bionic noise reduction configuration has been proposed; based on the protruding features of the leading edge of the humpback whale's pectoral fin, a "wave leading edge" bionic noise reduction configuration has been proposed. Numerous research papers have demonstrated that both bionic configurations can effectively suppress turbine noise.

[0003] Analysis of existing technologies shows that it is difficult to further reduce noise efficiently through a single biomimetic 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 suppression effect on both single-tone noise and broadband noise. This indicates that the combined design of porous medium and wave leading edge can retain the advantages of both wave leading edge and porous medium in noise suppression. Therefore, the porous-wave leading edge combined configuration is a biomimetic configuration with great noise reduction potential.

[0004] However, in experimental studies on the porous-wave leading edge combined configuration, two problems were found that need to be solved: On the one hand, when the blade thickness is thin and the wave crest of the wave leading edge is relatively sharp, the strength of the porous wave leading edge will be reduced, which will lead to deformation of the porous-wave leading edge configuration when blowing a fan in the experiment; on the other hand, in the manufacturing process of porous-wave leading edge blades, due to the presence of porous media, the porous media area needs to be processed separately from other parts of the blade, which raises the problem of combining the porous media with the solid part. Directly gluing them together will damage the aerodynamic performance of the blade, and the strength of the gluing cannot be guaranteed.

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

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a design method for porous wave leading edge biomimetic combined configuration blades wrapped with metal wire mesh. By using a porous wave leading edge combined configuration wrapped with metal wire mesh, the invention solves the problems faced by porous-wave leading edge combined biomimetic blades in experiments.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is: a design method for a porous wave-leading biomimetic composite blade configuration wrapped with metal wire mesh, characterized by including the following steps:

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

[0009] Step 2: Design a wave-shaped leading edge for the solid area, and extend the leaf root and leaf tip outward along the span according to the leaf shape outline to obtain a fixed area for fixing the leaf, thus obtaining the final wave-shaped leading edge solid area.

[0010] Step 3: Design a wave-shaped leading edge for the porous region. Match the trailing edge of the porous region with the wave-shaped leading edge of the solid region designed in Step 2 to obtain the wall shape of the porous region. Based on the wall shape of the porous region, make a metal wire mesh shell. Fill the middle area of ​​the metal wire mesh shell with porous medium material. Similarly, extend the leaf root and leaf tip outward along the span, with the extended part being solid for fixing the leaf. This results in the final porous region with a biomimetic combination of porous wave-shaped leading edge.

[0011] Step 4: Combine the solid wave leading edge region obtained in Step 2 with the porous region of the porous wave leading edge biomimetic composite configuration obtained in Step 3 to obtain a porous wave leading edge biomimetic composite configuration blade wrapped with metal wire mesh.

[0012] Furthermore, in the first step, the blade is divided into a porous region and a solid region. 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 0.35C from the leading edge. The area from the leading edge to 0.35C is the porous area, and the area from 0.35C to the trailing edge is the solid area.

[0014] (2) In order to reduce the loss of aerodynamic performance of the blade, the 0.35C position of the solid part is streamlined, and the leading edge of the solid area is extended forward by 0.10C. In order to ensure that the blade is finally assembled, the trailing edge of the porous area and the leading edge of the solid area need to be consistent.

[0015] Furthermore, the second step involves designing the wave leading edge of the solid region, specifically including the following steps:

[0016] (1) Based on the existing wave front design technology, the wave front configuration is designed for the front of the solid area. 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, thus obtaining the main part of the solid area of ​​the wave front.

[0017] (2) Based on the outline of the leaf root and leaf tip of the solid part after the wave leading edge is generated, extend outward by 0.1C to obtain a fixed area for fixing the blade, and obtain the final solid area of ​​the wave leading edge.

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

[0019] (1) Similarly, according to the wave front configuration design method used in the second step, the wave configuration of the porous region front 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, thus obtaining the porous medium wave front configuration.

[0020] (2) The trailing edge of the porous region and its connected internal wall surface 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) The porous region wave leading edge and its connected outer wall obtained in step (1), and the porous region wave trailing edge and its connected inner wall obtained in step (2), are designed with a metal wire mesh shell according to the shape of the wall. The metal wire mesh shell is divided into two parts, namely the front metal wire mesh and the rear metal wire mesh, and is extended outward by 0.1C according to the outline of the blade tip and the blade root. The extended part is solid and is used for fixing the blade.

[0022] (4) Based on the metal mesh shell of the porous region obtained in step (3), fill the internal space with porous medium and design the biomimetic porous wave leading edge as a metal mesh shell. The material properties of the porous medium can be selected and changed according to individual needs. In this invention, the biomimetic porous wave leading edge is designed as a metal mesh shell, which also facilitates the replacement of the porous medium material in the porous region during the experiment.

[0023] Furthermore, the design method for the porous wave leading edge biomimetic composite blade wrapped with metal wire mesh in the fourth step specifically includes: combining the solid wave leading edge region from the second step and the porous region of the porous wave biomimetic composite obtained in the third step to obtain the porous wave leading edge biomimetic composite blade wrapped with metal wire mesh proposed in this invention.

[0024] Furthermore, the blade fixing refers to the specific fixing method of the blade. 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. During the experiment, the extended fixing area is matched with the groove in the fixing baffle to fix the porous area of ​​the blade to the solid area in a better way.

[0025] The present invention adopts the above technical solution and has the following beneficial effects: The biomimetic 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 wire mesh shell. The strength of the porous-wave configuration can be increased by the metal wire mesh shell, and the application of the metal wire mesh shell can facilitate the replacement of the porous medium. Through the fixing device extending along the span, the porous area and the solid area can be fixed together well, thus solving the problem of fixing the porous-wave leading edge biomimetic combined blade. Attached Figure Description

[0026] Figure 1 This is a flowchart of the present invention;

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

[0028] Figure 3 This is a schematic diagram illustrating the division of the blade into porous and solid regions according to the present invention;

[0029] Figure 4 This is a schematic diagram of the wave leading edge design of the solid region of the present invention;

[0030] Figure 5 This is a schematic diagram of the biomimetic composite configuration design of the porous wave leading edge wrapped with metal wire mesh according to the present invention.

[0031] Figure 6 This is a schematic diagram showing the combination of the porous region and the solid region of the biomimetic blade of the present invention;

[0032] Figure 7 This is a schematic diagram of the biomimetic blade of the present invention;

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

[0034] Figure 9 This is a schematic diagram of the biomimetic blade fixing method of the present invention.

[0035] In the figure, 1 is the porous region; 2 is the solid region; 3 is the leading edge of the porous region; 4 is the trailing edge of the porous region; 5 is the leading edge of the solid region; 6 is the fixing device; 7 is the metal wire mesh shell; and 8 is the porous medium. Detailed Implementation

[0036] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0037] To achieve the above objectives, the present invention provides the following specific embodiments: Figures 1-9 As shown, the design method of porous wave-leading biomimetic composite blade with metal wire mesh wrapping is as follows: Figure 1 The steps shown are as follows:

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

[0039] Step 2: Design a wave-shaped leading edge for the leading edge 5 of the solid area, and extend the leaf root and leaf tip outwards to design a fixing device 6 for fixing the leaf during the experiment.

[0040] Step 3: Design a wave-shaped leading edge for the porous region 3. Match the leading edge of the porous region 4 with the leading edge of the solid region 5. The leading edge of the porous region is the same as the wave-shaped leading edge of the solid region designed in Step 2. Based on the wall of the porous region, make a metal wire mesh shell. Fill the middle area with porous medium material. Similarly, extend the leaf root and leaf tip outwards for fixing the leaf in the experiment.

[0041] Step 4: Combine the solid wave leading edge region obtained in Step 2 with the porous region of the porous wave leading edge biomimetic assembly obtained in Step 3 to obtain the design method of the porous wave leading edge biomimetic assembly blade with metal wire mesh wrapping.

[0042] The method for dividing the blade into porous and solid regions 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. The blade is divided into two parts at a distance of 0.35C from the leading edge. The area from the leading edge to 0.35C is the porous region 1, and the area from 0.35C to the trailing edge is the solid region 2.

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

[0045] The second step involves designing the wave leading edge of solid region 2, specifically including the following steps:

[0046] (1) Based on the existing wave front design technology, the wave front configuration of the solid area 5 is designed, 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, thus obtaining the main part of the solid area of ​​the wave front;

[0047] (2) Based on the outline of the leaf root and leaf tip of the solid part after the wave leading edge is generated, extend outward by 0.1C to generate the fixing device 6, which is used to fix the biomimetic leaf in the experiment, and obtain the final solid area of ​​the wave leading edge as shown in the figure. Figure 4 As shown.

[0048] The biomimetic design of the porous region in the third step mainly consists of three parts: a metal mesh shell, a porous medium, and a fixing device, specifically including the following steps:

[0049] (1) Similarly, according to the wave front configuration design method used in the second step, the wave configuration of the porous region front 3 is designed. 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, thus obtaining the porous medium wave front configuration.

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

[0051] (3) Design a wire mesh shell 7 for the porous region wave leading edge and its connected outer wall obtained in step (1), and the porous region wave trailing edge and its connected inner wall obtained in step (2). The wire mesh shell 7 is divided into two parts, such as... Figure 5 As shown, it is divided into a front metal mesh and a rear metal mesh, and extends outward by 0.1C according to the leaf tip and leaf root contours, for fixing the biomimetic leaf in the experiment;

[0052] (4) Based on the metal wire mesh shell 7 of the porous region obtained in step (3), fill the internal space with porous medium 8. The material properties of the porous medium can be selected and changed according to individual needs. In this invention, the biomimetic porous wave leading edge is designed as a metal wire mesh shell, which also facilitates the replacement of porous medium material in the porous region during the experiment.

[0053] The fourth step, designing a porous wave-leading biomimetic composite blade with a wire mesh wrapping, specifically includes: combining the solid wave-leading region from the second step and the porous wave-bionic composite region obtained in the third step. The specific combination method is as follows: Figure 6 As shown, we obtained Figure 7 The design method of porous wave leading edge biomimetic composite blade with metal wire mesh wrapping is shown.

[0054] The specific method of fixing the blades in the experiment mentioned in this invention is as follows: Figure 8 and Figure 9 As shown, a fixing baffle needs to be designed to match the fixing device of the biomimetic blade proposed in this invention. A corresponding contour groove is formed on the baffle. During the experiment, the extending fixing device in the biomimetic blade design is matched with the groove in the fixing baffle, as shown below. Figure 8 As shown in the figure, the porous area of ​​the bionic leaf can be fixed together with the solid area in a better way.

[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 principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for designing a porous wave-shaped leading edge biomimetic composite blade wrapped with metal wire mesh, characterized in that, Includes the following steps: Step 1: Divide the blade into a porous region (1) and a solid region (2), specifically: 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 0.35C from the leading edge. The area from the leading edge to 0.35C is the porous area (1), and the area from 0.35C to the trailing edge is the solid area (2). 2) In order to reduce the loss of aerodynamic performance of the blade, the solid part at the 0.35C position is streamlined, and the leading edge (5) of the solid region is extended forward by 0.10C. In order for the blade to be finally assembled, the trailing edge (4) of the porous region is consistent with the leading edge (5) of the solid region. Step 2: Design a wave-like leading edge for the leading edge (5) of the solid area, and extend the leaf root and leaf tip outwards to design a fixing device (6) for fixing the leaf in the experiment, specifically: 1) Based on the existing wave front design technology, the wave front configuration of the solid region (5) is designed, 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, so as to obtain the main part of the solid region (2) with the wave front; 2) Based on the outline of the leaf root and leaf tip of the solid region (2) with the wave leading edge, extend outward by 0.1C to generate a fixing device (6) for fixing the bionic leaf in the experiment, and obtain the final wave leading edge solid region. Step 3: Design a wave-shaped leading edge (3) for the porous region, and match the trailing edge (4) of the porous region with the leading edge of the solid region (2). Based on the wall of the porous region (1), make a metal wire mesh shell (7) filled with porous medium material. Similarly, extend the leaf roots and tips outwards for fixing the leaves in the experiment. The specific design steps are as follows: 1) Based on the wave front configuration design method adopted in the second step, the wave configuration design of the porous region front (3) is carried out. 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, thus obtaining the porous medium wave front. 2) The inner wall of the porous region tail edge (4) and the porous region tail edge (4) are consistent with the front edge of the solid region (2) with the wave front edge, that is, the porous region tail edge (4) has the same wave configuration as the solid region front edge (5); 3) Design a metal wire mesh shell (7) for connecting the outer wall surface of the porous medium wave front edge and the outer wall surface of the porous region wave tail edge and the inner wall surface of the porous region wave tail edge. The metal wire mesh shell (7) is divided into two parts, namely the front metal wire mesh and the rear metal wire mesh, and extends outward by 0.1C according to the leaf tip and leaf root outline, for fixing the biomimetic leaf in the experiment; 4) The internal space between the front and rear metal wire meshes of the metal wire mesh shell (7) in the porous region is filled with porous medium (8), that is, the porous medium wave front edge is designed as the porous medium wave front edge wrapped by the metal wire mesh shell, which also facilitates the replacement of porous medium material in the porous region during the experiment. Step 4: Combine the solid region (2) with the wave leading edge and the porous region (1) with the porous medium wave leading edge wrapped in a metal mesh shell to obtain the biomimetic composite blade with the porous wave leading edge wrapped in a metal mesh. It also includes a fixing baffle that matches the fixing device (6). A corresponding contour groove is opened on the fixing baffle. During the experiment, the fixing device (6) extended in the design of the porous wave leading edge bionic combined configuration blade is matched with the groove in the fixing baffle, that is, the porous area (1) and the solid area (2) of the porous wave leading edge bionic combined configuration blade are fixed.

Images