Porous material noise reduction propeller optimization method and device, propeller and storage medium

Abstract

The invention relates to a porous material noise reduction propeller optimization method and device, a propeller and a storage medium, and the method comprises the steps: determining key attribute parameters of a porous material noise reduction propeller model, and determining a plurality of radial distances of a porous material in the porous material noise reduction propeller model; hydrodynamic characteristic calculation and sound field characteristic calculation are carried out on the porous material noise reduction propeller model through the key attribute parameters and each radial distance, a sound field calculation result of each radial distance is obtained, and the sound field calculation result of each radial distance is analyzed and compared with a sound field of an original propeller; the radial distance capable of reaching the target is determined according to the comparison result, the target radial distance capable of reaching the target is determined according to the comparison result, and in the process of determining the target radial distance of the porous material, the hydrodynamic characteristics and the sound field characteristics of the porous material noise reduction propeller are considered at the same time; therefore, the purposes of controlling the flow noise of the propeller and reducing the influence on the hydrodynamic characteristics of the propeller are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of propeller optimization, and particularly to a method, device, propeller and storage medium for optimizing a porous material noise reduction propeller. Background Art

[0002] As one of the important units of the power system of underwater ship equipment, under the action of the viscous force between the fluid and the wall surface, a vortex structure will form on the surface of the propeller blade and move along the radial direction of the blade surface, and finally shed at the tip edge and enter the downstream flow field. The research results of many scholars at home and abroad show that the spatio-temporal evolution process of the vortex structure, including the formation, movement, decomposition and disappearance of the vortex, is one of the important reasons for the generation of propeller flow noise. As one of the main noise sources of ship equipment, the effective control of propeller flow noise is of great significance for comprehensively improving the acoustic performance of ship equipment. As a spatial micro-channel structure, porous materials show significant advantages in the field of flow noise control by regulating the flow state of the fluid to accelerate the decomposition and disappearance of the vortex structure in the flow field and inhibit or delay the shedding process of the vortex structure, thereby increasing the stability of the flow field.

[0003] In order to regulate the hydrodynamic behavior to achieve effective control of flow noise, many scholars at home and abroad have carried out a series of studies on the flow field and acoustic field characteristics of porous materials. Porous materials can indeed affect the hydrodynamic characteristics of the propeller. However, porous materials have a complex spatial structure and require a large amount of computing resources, resulting in most existing studies focusing on models with simple geometric parameters such as the surface of a cylinder and the trailing edge of a hydrofoil, and it is impossible to control the flow noise of the propeller while reducing the impact on the hydrodynamic characteristics of the propeller.

[0004] Therefore, there is an urgent need to propose a method, device, propeller and storage medium for optimizing a porous material noise reduction propeller to solve the technical problem in the prior art that setting porous materials through simple geometric parameter models cannot control the flow noise of the propeller while reducing the impact on the hydrodynamic characteristics of the propeller. Summary of the Invention

[0005] In view of this, it is necessary to provide a method, device, propeller and storage medium for optimizing a porous material noise reduction propeller to solve the technical problem in the prior art that it is impossible to control the flow noise of the propeller while reducing the impact on the hydrodynamic characteristics of the propeller.

[0006] To solve the above problems, in a first aspect, the present invention provides a method for optimizing a porous material noise reduction propeller, including: Obtain the key attribute parameters of the porous material noise reduction propeller model, and determine multiple radial distances of the porous material in the porous material noise reduction propeller model; the porous material noise reduction propeller model includes a propeller blade composed of a porous material and a solid structure. Perform hydrodynamic characteristic calculation and acoustic field characteristic calculation on the porous material noise reduction propeller model according to the key attribute parameters and multiple radial distances to obtain the acoustic field calculation results for each radial distance. Analyze and compare the acoustic field calculation results for each radial distance with the acoustic field of the original propeller to obtain a comparison result, and determine the target radial distance of the porous material on the propeller blade according to the comparison result.

[0007] In a possible implementation manner, the performing hydrodynamic characteristic calculation and acoustic field characteristic calculation on the porous material noise reduction propeller model according to the key attribute parameters and multiple radial distances to obtain the acoustic field calculation results for each radial distance includes: Obtain source term parameters according to the key attribute parameters. Perform hydrodynamic characteristic calculation on the porous material noise reduction propeller model according to the source term parameters and multiple radial distances to obtain the flow field calculation results for each radial distance. Perform acoustic field characteristic calculation on the porous material noise reduction propeller model according to the flow field calculation results to obtain the acoustic field calculation results for each radial distance.

[0008] In a possible implementation manner, the obtaining source term parameters according to the key attribute parameters includes: Calculate the key attribute parameters to obtain the viscous drag coefficient and inertial drag coefficient of the porous material. Input the viscous drag coefficient and the inertial drag coefficient into a preset source term equation for calculation to obtain source term parameters.

[0009] In a possible implementation manner, the performing hydrodynamic characteristic calculation on the porous material noise reduction propeller model according to the source term parameters and multiple radial distances to obtain the flow field calculation results for each radial distance includes: Perform polyhedral mesh division on the porous material noise reduction propeller model one by one according to the multiple radial distances to obtain the flow field mesh files for each radial distance. Input the source term parameters and the flow field mesh files into a flow field simulation platform for hydrodynamic characteristic calculation to obtain the flow field calculation results for each radial distance.

[0010] In a possible implementation, the porous material noise reduction propeller model includes a porous material region, a peripheral stationary domain, and an intermediate rotating domain; calculating the acoustic field characteristics of the porous material noise reduction propeller model according to the flow field calculation results to obtain the acoustic field calculation results for each radial distance, including: Determine the interface according to the peripheral stationary domain and the intermediate rotating domain; Set the peripheral stationary domain as a volume sound source, set the interface as a surface sound source, and perform acoustic mesh division on the volume sound source and the surface sound source one by one according to the multiple radial distances to obtain the acoustic mesh file for each radial distance; Input the flow field mesh file into an acoustic simulation platform to perform acoustic field characteristic calculation, and obtain the acoustic field calculation results for each radial distance.

[0011] In a possible implementation, the acoustic field calculation result is a sound pressure level spectrum curve; analyzing and comparing the acoustic field calculation results for each radial distance with the acoustic field of the original propeller to obtain a comparison result, including: Compare the sound pressure level spectrum curve for each radial distance with the original sound pressure level spectrum curve of the original propeller to obtain a target sound pressure level spectrum curve; Obtain the comparison result according to the target sound pressure level spectrum curve.

[0012] In a possible implementation, determining the multiple radial distances of the porous material in the porous material noise reduction propeller model includes: Set a preset porous material region division ratio and an initial radius; Determine the preset porous material region division ratio as the initial radial distance; Perform equal division and superposition on the initial radial distance according to the preset porous material region division ratio to obtain multiple radial distances; the multiple radial distances are all smaller than the initial radius.

[0013] In a second aspect, the present invention also provides a porous material noise reduction propeller optimization device, including: A parameter acquisition module, configured to acquire key attribute parameters of a porous material noise reduction propeller model, and determine multiple radial distances of the porous material in the porous material noise reduction propeller model; the porous material noise reduction propeller model includes a propeller blade composed of a porous material and a solid structure; An acoustic field simulation module, configured to perform hydrodynamic characteristic calculation and acoustic field characteristic calculation on the porous material noise reduction propeller model according to the key attribute parameters and multiple radial distances to obtain the acoustic field calculation results for each radial distance; A result comparison module is configured to analyze and compare the sound field calculation results of each radial distance with the sound field of the original propeller, obtain a comparison result, and determine a target radial distance of the porous material on the propeller blade according to the comparison result.

[0014] In a third aspect, an embodiment of the present invention discloses a porous material noise reduction propeller, which is optimized according to each step of the above-mentioned porous material noise reduction propeller optimization method embodiment.

[0015] In a fourth aspect, an embodiment of the present invention discloses a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, each step of the above-mentioned porous material noise reduction propeller optimization method embodiment is implemented.

[0016] The beneficial effects of the present invention are as follows: A porous material noise reduction propeller model is set up, key attribute parameters are obtained, and multiple radial distances of the porous material in the porous material noise reduction propeller model are determined. The flow noise of the propeller can be controlled by the radial distance of the porous material. In order to control the flow noise of the propeller while reducing the influence on the hydrodynamic characteristics of the propeller, each radial distance can be simulated through the porous material noise reduction propeller model. The process can be to calculate the hydrodynamic characteristics and sound field characteristics of the porous material noise reduction propeller model through the key attribute parameters and each radial distance, obtain the sound field calculation results of each radial distance, and then analyze and compare the sound field calculation results of each radial distance with the sound field of the original propeller. The target radial distance that can achieve the purpose is determined through the comparison result. In other words, during the determination process of the target radial distance of the porous material, the hydrodynamic characteristics and sound field characteristics of the porous material noise reduction propeller are considered simultaneously, so as to achieve the purpose of controlling the flow noise of the propeller while reducing the influence on the hydrodynamic characteristics of the propeller. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic flowchart of an embodiment of the porous material noise reduction propeller optimization method provided by the present invention; Figure 2 It is a schematic structural diagram of an embodiment of the original propeller model provided by the present invention; Figure 3 It is a schematic structural diagram of an embodiment of the porous material structure provided by the present invention; Figure 4 For the present invention Figure 1 It is a schematic flowchart of an embodiment of step S101 in the present invention; Figure 5 It is a schematic structural diagram of an embodiment of the porous material noise reduction propeller model provided by the present invention; Figure 6 For the present inventionFigure 1 Schematic flowchart of an embodiment of step S102; Figure 7 Schematic structural diagram of an embodiment of the comparison diagram of Q-criterion vortices of the original propeller and the porous material propeller provided by the present invention; Figure 8 Schematic coordinate diagram of an embodiment of the comparison diagram of sound pressure level frequency spectra of acoustic monitoring points provided by the present invention; Figure 9 Schematic coordinate diagram of another embodiment of the comparison diagram of sound pressure level frequency spectra of acoustic monitoring points provided by the present invention; Figure 10 Schematic structural diagram of an embodiment of the porous material noise reduction propeller optimization device provided by the present invention. Detailed implementation manners

[0018] The preferred embodiments of the present invention will be specifically described below with reference to the accompanying drawings. The accompanying drawings form a part of this application and are used together with the embodiments of the present invention to explain the principles of the present invention, and are not used to limit the scope of the present invention.

[0019] As Figure 1 shown, a specific embodiment of the present invention discloses a porous material noise reduction propeller optimization method, including: S101. Obtain the key attribute parameters of the porous material noise reduction propeller model, and determine multiple radial distances of the porous material in the porous material noise reduction propeller model; the porous material noise reduction propeller model includes a propeller blade composed of a porous material and a solid structure; The porous material noise reduction propeller optimization method provided by the embodiments of the present application can be applied to a propeller optimization system. Among them, the porous material noise reduction propeller optimization can be based on a software system running on a terminal device. The terminal device can be a server, a tablet computer, an augmented reality (AR) / virtual reality (VR) device, a notebook computer, an ultra-mobile personal computer (UMPC), a netbook, a personal digital assistant (PDA), a mobile phone and other terminal devices. The embodiments of the present application do not impose any restrictions on the specific type of the terminal device.

[0020] Among them, the DTMB4119 standard propeller can be taken as an example, and the original propeller model of the porous material propeller can be constructed through simulation software. In practical applications, it is not limited to the DTMB4119 standard propeller. As Figure 2 shown, Figure 2This is a schematic diagram of the original propeller model constructed by simulation software. The radial cross-section of the hub is circular, and the axial cross-section is elliptical. The hub geometry can be adjusted according to the application scenario. The blade cross-section is a NACA0066 standard airfoil with different thicknesses. A single propeller blade is obtained by surface closing the airfoil curve at different radial distances. The blades are circumferentially arrayed to complete the construction of the DTMB4119 standard propeller model. The propeller blade tip is an area where vortex structures are concentrated and shed. The porous material noise reduction propeller model of an embodiment of the present invention includes a propeller blade composed of a porous material and a solid structure. Specifically, in the simulation software, a part of the solid structure of the propeller tip area is replaced with a porous material to achieve regulation of the fluid flow state. The porous material is applied to the surface of the propeller blade in the form of a surface additional layer or the like to achieve regulation of the fluid flow state. The porous material structure used in the embodiment of the present invention is as follows: Figure 3 As shown in the figure, in actual use, porous materials have various isotropic and anisotropic properties, and the pore structure has various geometric parameters such as circular, square, polygonal, etc. The porous materials with different property parameters are applied to the propeller blades to achieve the regulation of the fluid flow state. In order to better detect and analyze the propeller of porous materials, a porous material noise reduction propeller model is constructed based on the assumption of the isotropic properties of the propeller of porous materials, and the key property parameters are obtained according to the situation of the porous material noise reduction propeller model. The key property parameters may include the permeability of porous materials, the average pore size and other parameters.

[0021] S102, performing hydrodynamic characteristic calculation and acoustic field characteristic calculation on the porous material noise reduction propeller model according to key attribute parameters and multiple radial distances, and obtaining an acoustic field calculation result for each radial distance; Among them, in order to test each porous material noise reduction propeller model, the hydrodynamic characteristics and acoustic field characteristics can be calculated according to the key property parameters and the porous material noise reduction propeller model at each radial distance, so that the porous material noise reduction propeller model can be tested in many aspects and the acoustic field calculation results of the porous material noise reduction propeller model at each radial distance can be obtained.

[0022] S103, analyzing and comparing the acoustic field calculation result of each radial distance with the acoustic field of the original propeller to obtain a comparison result, and determining the target radial distance of the porous material on the propeller blade according to the comparison result.

[0023] Among them, after obtaining the sound field calculation results of each radial distance, it can be compared and analyzed with the sound field of the original propeller to obtain the comparison results of each radial distance, and then the porous material noise reduction propeller can be optimized according to the target radial distance that meets the requirements in the comparison results.

[0024] Compared with the prior art, the present embodiment provides a porous material noise reduction propeller model, obtains key property parameters, and also determines multiple radial distances of the porous material in the porous material noise reduction propeller model. The flow noise of the propeller can be controlled by the radial distance of the porous material. In order to control the flow noise of the propeller while reducing the impact on the hydrodynamic characteristics of the propeller, the porous material noise reduction propeller model can be used to simulate each radial distance. The process can be to calculate the hydrodynamic characteristics and acoustic field characteristics of the porous material noise reduction propeller model through the key property parameters and each radial distance, obtain the acoustic field calculation results of each radial distance, and then analyze and compare the acoustic field calculation results of each radial distance with the acoustic field of the original propeller. The target radial distance that can achieve the purpose can be determined through the comparison results. In other words, during the determination process of the target radial distance of the porous material, the hydrodynamic characteristics and acoustic field characteristics of the porous material noise reduction propeller are considered simultaneously, so as to achieve the purpose of controlling the flow noise of the propeller while reducing the impact on the hydrodynamic characteristics of the propeller.

[0025] In some embodiments of the present invention, as Figure 4 shown, step S101 includes: S401. Set a preset porous material area division ratio and an initial radius; In a specific embodiment of the present invention, with the position of the rotating shaft as the center in the propeller rotation plane, considering that there are relatively high requirements for the structural strength during the rotation of the propeller, the application area of the porous material can be determined according to the radius of the propeller. For example, if the radius of the propeller is R, in order to ensure the strength of the propeller, the application area of the porous material cannot exceed R / 2. When the radius of the propeller is 100 mm, the application area of the porous material cannot exceed 50 mm. Then, the value range of the propeller radius can be set as 60 mm to 100 mm. In order to perform more accurate optimization, the values within the value range are divided according to a preset equal division to obtain multiple optimization objects. The preset equal division can be set according to the actual situation, and the present invention embodiment does not limit this here. For example, the initial radius of 60 mm to 100 mm is 40 mm, and the preset equal division is 5, then 40 / 5 = 8 mm.

[0026] S402. Determine the preset porous material area division ratio as the initial radial distance; S403. Perform equal division and superposition on the initial radial distance according to the preset porous material area division ratio to obtain multiple radial distances; all the multiple radial distances are less than the initial radius.

[0027] In a specific embodiment of the present invention, the initial radial distance can be set to ΔR = 8 mm. Then, the multiple radial distances within 40 mm can be ΔR = 8 mm, 2ΔR = 16 mm, 3ΔR = 24 mm, 4ΔR = 32 mm respectively. As Figure 5 shown, they are respectively the original propeller model constructed by simulation software, the porous material noise reduction propeller model with ΔR = 8 mm, the porous material noise reduction propeller model with 2ΔR = 16 mm, the porous material noise reduction propeller model with 3ΔR = 24 mm, and the porous material noise reduction propeller model with 4ΔR = 32 mm. The dark area at the tip of each propeller blade of the porous material noise reduction propeller model is the porous material area. Among them, the multiple radial distances are obtained by equal division and superposition, and can also be processed according to other variation rules, such as arithmetic sequence, geometric sequence and other methods.

[0028] In some embodiments of the present invention, as Figure 6 shown, step S102 includes: S601. Obtain the source term parameters according to the key attribute parameters; Among them, the source term parameter refers to the term that serves as an external input or driving force in the ordinary differential equation, and is usually located on the right side of the equation, called the non - homogeneous term.

[0029] S602. Calculate the hydrodynamic characteristics of the porous material noise reduction propeller model according to the source term parameters and multiple radial distances, and obtain the flow field calculation results for each radial distance; S603. Calculate the acoustic field characteristics of the porous material noise reduction propeller model according to the flow field calculation results, and obtain the acoustic field calculation results for each radial distance.

[0030] In a specific embodiment of the present invention, after obtaining the key attribute parameters, the key attribute parameters can be calculated to obtain the source term parameters. Thus, the hydrodynamic characteristics can be calculated according to the source term parameters and the porous material noise reduction propeller model for each radial distance, and the flow field calculation results for each radial distance can be obtained. Then, the corresponding porous material noise reduction propeller model can be detected according to the flow field calculation results, and thus the acoustic field calculation results of the porous material noise reduction propeller model for each radial distance can be obtained.

[0031] In some embodiments of the present invention, step S601 includes: Calculate the key attribute parameters to obtain the viscous drag coefficient and inertial drag coefficient of the porous material.

[0032] In a specific embodiment of the present invention, the viscous drag coefficient and inertial drag coefficient of the porous material can be calculated by calculating the key attribute parameters. The calculations are shown in formulas (1) and (2): α=1 / K= (D p 2 ×ε 3 ) / ( 150× ( 1 - ε ) 2 ) (1) C 2 = ( 3.5× ( 1 - ε )) / ( D p ×ε 3 ) (2) In the formula, K is the viscous resistance coefficient of the porous material; C 2 is the inertial resistance coefficient; D p is the average pore diameter, D p = 2.36 × 10 -4 ; ε is the permeability of the porous material, ε = 0.8.

[0033] The viscous resistance coefficient and the inertial resistance coefficient are input into a preset source term equation for calculation to obtain the source term parameters.

[0034] In a specific embodiment of the present invention, the viscous resistance coefficient of the porous material of the belt calculated by the above formulas (1) and (2) K = 2.111 × 10 8 , the inertial resistance coefficient is C 2 = 5.802 × 10 3 , and the above key property parameters of the porous material can be adjusted according to the propeller model, noise reduction requirements, application scenarios, etc. Then, the viscous resistance coefficient and the inertial resistance coefficient can be input into a preset source term equation for calculation to obtain the source term parameters, where the preset source term equation is as shown in formula (3): S i =- (( μ×u i ) / α ) + ( C 2 ×ρ|u|u i ) / 2 ) ；K=1 / α (3) In the formula, μis the kinematic viscosity coefficient of the fluid medium, u i ( i = 1, 2, 3) are the velocity components in the x, y, and z directions; u is the macroscopic velocity of the fluid, i.e., the resultant velocity; S i is the source term parameter; ρ is the fluid density.

[0035] In some embodiments of the present invention, step S602 includes: Performing polyhedral mesh division on the porous material noise reduction propeller model one by one according to multiple radial distances to obtain the flow field mesh file for each radial distance.

[0036] In a specific embodiment of the present invention, in order to verify multiple radial distances, polyhedral mesh division can be performed on the porous material noise reduction propeller model for each radial distance. Specifically, a mesh generation software can be used to perform mesh division on the porous material region, the outer stationary domain, and the intermediate rotating domain. In the embodiments of the present invention, FluentMeshing can be used to perform polyhedral mesh division on the porous material noise reduction propeller model. This step supports multiple mesh generation software. The specific fluid computational domain discretization process is as follows: A shared topology is adopted between the porous material region and the fluid rotating domain to ensure co - nodes in the subsequent mesh division process and reduce the error caused by interpolation during data transfer; Pull down the File Name toolbar to import the propeller fluid domain model; Perform surface mesh division on the hub, blades, rotating domain - stationary domain interface, inlet, outlet, and outer wall surface respectively according to the propeller geometric dimensions. In the embodiments of the present invention, the minimum surface mesh size of the DTMB4119 propeller is 1.25 mm at the blade size, and the maximum surface mesh size is 25 mm at the outer wall surface; Given the above geometric surface boundary attributes in the Describe Geometry toolbar, which are: wall, wall, interface, inlet, outlet, and symmtery in sequence; According to the requirements of the LES turbulence model for the boundary layer, a total of 20 layers of boundary layers are divided. The thickness of the first - layer boundary layer is 0.05 mm, and the growth rate between different boundary layers is 1.2; Generate a spatial volume mesh based on the above surface mesh, i.e., the flow field mesh file.

[0037] Input the source term parameter and the flow field mesh file into the flow field simulation platform for hydrodynamic characteristic calculation to obtain the flow field calculation results for each radial distance.

[0038] In the embodiments of the present invention, Ansys Fluent is used to carry out the simulation calculation of the hydrodynamic characteristics of the propeller with porous materials. This step supports a variety of fluid simulation software. The specific parameter settings and calculation process are as follows: Read the divided flow field mesh file obtained in the above process through the File-Read-Mesh toolbar; Use the General-Scale function to check the size of the mesh file. Ansys Fluent defaults to using the mm unit. If the size is too large (or too small), the size of the mesh file is adjusted by multiplying by the corresponding scaling factor; The rotational motion of the propeller results in the coexistence of multi-scale vortex structures in the flow field. Since the Large Eddy Simulation (LES) model has better capturing ability for multi-scale vortex structures, the LES turbulence model is selected in the Viscous toolbar to solve the transient flow field of the propeller; Multiple fluid calculation domains such as the stationary domain, the rotating domain, and the porous material region are included in Cell-Zone-Conditions, and the physical property parameters need to be set separately. Among them, the stationary domain remains the default setting; In the rotating domain, check the Mesh Motion function, set the X-axis as the rotation axis, and set the rotational speed to 792 rpm, which is the design rotational speed of the DTMB4119 propeller; In the porous material region, check both the Mesh Motion function and the Porous Zone function. The parameter settings of the Mesh Motion function are the same as those in the rotating domain, and the parameter settings of the Porous Zone function are based on the source term parameters calculated from the key attribute parameters. Set the boundary conditions in the Boundary Conditions toolbar, and adopt a velocity inlet and a pressure outlet to approximate the process of fluid flowing through the propeller in the actual environment as much as possible. The inlet velocity is calculated based on the design condition of the DTMB4119 propeller, that is, the advance coefficient J = v / (nD2) = 0.833 (v is the inlet velocity, n is the rotational speed, and D is the propeller diameter). The interface is used between the stationary domain and the rotating domain to achieve data exchange to avoid the consumption of a large amount of computing resources caused by the synchronous rotation of the peripheral fluid calculation domain. The peripheral wall is set to Symmetry to simulate an infinite fluid domain. Select the SIMPLEC algorithm to solve the velocity-pressure coupling of the transient flow field, which can better balance the computing efficiency and computing speed. The time step of the transient flow field is set to the time taken for the propeller to rotate 1 o the time taken, and the velocity field file is output every time it rotates 1 o time, and the flow field calculation results are output every time it rotates 10 o times to ensure that the flow field calculation results of the propeller model with porous material noise reduction are obtained completely. This step supports a variety of simulation calculation software. Through the above process, the propeller model with porous material noise reduction at each radial distance can be processed, and the flow field calculation results at each radial distance can be output.

[0039] In some embodiments of the present invention, the porous material noise reduction propeller model includes a porous material region, a peripheral stationary region, and an intermediate rotating region; step S603 includes: Determine the interface according to the peripheral stationary region and the intermediate rotating region; Set the peripheral stationary region as a volume sound source, set the interface as a surface sound source, and perform acoustic mesh generation on the volume sound source and the surface sound source one by one according to multiple radial distances to obtain an acoustic mesh file for each radial distance; Input the flow field mesh file into an acoustic simulation platform to calculate the sound field characteristics and obtain the sound field calculation results for each radial distance.

[0040] In a specific embodiment of the present invention, in order to facilitate the processing of the porous material noise reduction propeller model, the connection region between the peripheral stationary region and the intermediate rotating region is determined as the interface. The peripheral stationary region of the porous material noise reduction propeller model can be set as a volume sound source, and the interface (i.e., the Interface surface) can be set as a surface sound source. Based on the Lighthill acoustic analogy theory, the sound pressure level spectrum curve at the acoustic monitoring point is obtained. In the embodiments of the present invention, the Actran software is used for sound field calculation. The acoustic mesh generation follows the above steps for generating the flow field mesh file, but different from the hydrodynamic calculation, the size of the acoustic mesh λ needs to be calculated according to the formula λ = c / (8 f max )( c where is the speed of sound, f max is the maximum calculation frequency), so that the volume sound source and the surface sound source for each radial distance can be subjected to acoustic mesh generation through this step to obtain an acoustic mesh file for each radial distance. Then, using the acoustic mesh file as the input, CAA calculation is performed based on the Caasources function in the ICFD module of the acoustic calculation software to obtain the distributions of the volume sound source (Lighthill Volume) and the surface sound source (Lighthill Surface) in the time domain. Using the DFT function in the ICFD module, the above acoustic distribution in the time domain is converted into an acoustic distribution in the frequency domain; double-click the Direct Frequency Response toolbar to set the acoustic calculation range. In the embodiments of the present invention, the acoustic calculation frequency range is not set separately and is automatically assigned by the software; through the Components toolbar, the peripheral stationary region is set as the acoustic region, and the outer wall surface is set as the sound propagation region; the volume sound source and the surface sound source items are added respectively in the Boundary Conditions - Aero-acoustics toolbar; an acoustic monitoring point is added in the Post Processing toolbar to generate the sound pressure level spectrum curve at the monitoring point, that is, the sound field calculation result.

[0041] In some embodiments of the present invention, the sound field calculation result is a sound pressure level spectrum curve; step S103 includes: Comparing the sound pressure level spectrum curve of each radial distance with the original sound pressure level spectrum curve of the original propeller to obtain a target sound pressure level spectrum curve; In a specific embodiment of the present invention, for more accurate judgment, the Q-criterion vortex structure distribution of the porous material propeller model can be obtained through a flow field simulation platform, as Figure 7 shown, Figure 7 is a comparison diagram of the Q-criterion vortex distributions of the original propeller and the porous material propeller. The first one is the Q-criterion vortex structure distribution diagram of the original propeller, and the following are the Q-criterion vortex distribution diagrams of the porous material propeller models with ΔR = 8mm, 2ΔR = 16mm, 3ΔR = 24mm, and 4ΔR = 32mm respectively. It can be found through comparison that with the application of the porous material at the propeller tip, the retention time of the large-volume vortex structure in the flow field can be significantly shortened. In addition, as the radial distance of the porous material region gradually increases, it can be clearly observed that small-volume vortex structures contact and merge into large-volume vortex structures.

[0042] As Figure 8 and Figure 9 shown, Figure 8 is a comparison diagram of the sound pressure level spectrum curves of the original propeller and the acoustic monitoring points with ΔR = 8mm and 2ΔR = 16mm, Figure 9 is a comparison diagram of the sound pressure level spectrum curves of the original propeller Original and the acoustic monitoring points with 3ΔR = 24mm and 4ΔR = 32mm, Figure 8 The black curve in is the sound pressure level spectrum curve of the original propeller Original, the red curve is the sound pressure level spectrum curve of ΔR = 8mm, and the blue curve is the sound pressure level spectrum curve of 2ΔR = 16mm, Figure 9 The black curve in is the sound pressure level spectrum curve of the original propeller Original, the red curve is the sound pressure level spectrum curve of 3ΔR = 24mm, and the blue curve is the sound pressure level spectrum curve of 4ΔR = 32mm, Figure 8 and Figure 9 The x-axis of is frequency and the y-axis is sound pressure level. By comparing the sound pressure level spectrum curves of the original model with ΔR = 8mm, 2ΔR = 16mm, 3ΔR = 24mm, and 4ΔR = 32mm, it can be found that the application of a small range of porous materials at the propeller tip can significantly reduce the flow noise level caused by the periodic rotation of the propeller. As the area of the porous material region at the propeller tip gradually increases, the flow noise level gradually rises and even is excited.

[0043] According to the target sound pressure level spectrum curve, a comparison result is obtained.

[0044] In a specific embodiment of the present invention, it can be obtained that the comparison result shows that when the radial distance of the porous material is ΔR = 8 mm, effective control of flow noise within the entire calculation frequency range can be achieved. By calculating and comparing the distribution of Q-criterion vortex structures in the flow fields of the original propeller and the propeller with a porous material radial distance of ΔR = 8 mm, it can be found that the porous material disrupts the integrity of the shed vortex structure at the propeller tip, and the process of vortex structure decomposition and collapse is advanced, resulting in effective control of the propeller flow noise. When the radial distance of the porous material is 2ΔR = 16 mm, the ability of the porous material propeller to control flow noise only increases slightly within a small range. Among them, the noise sound pressure level within the frequency range of 100 - 500 Hz further decreases slightly within a small range, and the sound pressure level within the frequency range greater than 1000 Hz is the same as that of the original model. By comparing the distribution of Q-criterion vortices, it can be found that there is a phenomenon of fusion of small-volume vortices in the local flow field, Figure 7 the fused vortices in Figure 7 . When the radial distances of the porous material are 3ΔR = 24 mm and 4ΔR = 32 mm, the sound pressure level of the spectral curve is basically the same as or slightly higher than that of the original model at this time. From the distribution of the Q-criterion vortex structure, it can be found that there is a common phenomenon of fusion of small-volume vortex structures in the circumferential fluid at this time.

[0045] Furthermore, according to the comparison results, it can be determined that the porous material noise-reducing propeller models with radial distances of ΔR = 8 mm and 2ΔR = 16 mm can control the propeller flow noise while reducing the impact on the hydrodynamic characteristics of the propeller. Therefore, it can be determined that the target radial distances are ΔR = 8 mm and 2ΔR = 16 mm. The radial distance of the porous material of the porous material propeller can be set to ΔR = 8 mm or 2ΔR = 16 mm to achieve the purpose of optimizing the porous material propeller.

[0046] In the embodiment of the present invention, aiming at the problem of flow noise in the complex flow field of the propeller, a porous material noise-reducing propeller is proposed by applying the porous material to the propeller tip. The spatio-temporal evolution process of the vortex structure in the flow field is one of the important reasons for the generation of propeller flow noise. Compared with the original propeller, the micro-channel structure of the porous material guides the fluid, advancing the process of decomposition and collapse of the vortex structure at the tip, shortening the retention time of the vortex structure in the flow field. By comparing the sound pressure level spectral curves of the acoustic monitoring points, the application of the porous material at the propeller tip can effectively control the propeller flow noise. By studying the influence law of the area of the porous material region on the propeller flow noise, the optimal design of the area of the porous material region on the propeller blade is realized.

[0047] Specifically, the embodiments of the present invention are only proposed for further describing the modeling and numerical calculation methods proposed by the embodiments of the present invention. Researchers in the relevant technical fields can adjust the implementation objects within the scope of the present invention to obtain a better working experience. For example, changing the propeller model, adjusting the porosity and average pore diameter of the porous material, etc. to adapt to different application scenarios and obtain better propeller flow noise control effects in engineering practice.

[0048] In order to better implement the porous material noise reduction propeller optimization method in the embodiments of the present invention, correspondingly, based on the porous material noise reduction propeller optimization method, the embodiments of the present invention also provide a porous material noise reduction propeller optimization device, as Figure 10 shown, the porous material noise reduction propeller optimization device 1000 includes: A parameter acquisition module 1001, configured to acquire key attribute parameters of a porous material noise reduction propeller model, and determine a plurality of radial distances of the porous material in the porous material noise reduction propeller model; the porous material noise reduction propeller model includes a propeller blade composed of a porous material and a solid structure; An acoustic field simulation module 1002, configured to perform hydrodynamic characteristic calculation and acoustic field characteristic calculation on the porous material noise reduction propeller model according to the key attribute parameters and the plurality of radial distances, and obtain an acoustic field calculation result for each radial distance; A result comparison module 1003, configured to analyze and compare the acoustic field calculation result of each radial distance with the acoustic field of the original propeller, obtain a comparison result, and determine a target radial distance of the porous material on the propeller blade according to the comparison result.

[0049] The porous material noise reduction propeller optimization device 1000 provided in the above embodiments can implement the technical solutions described in the embodiments of the above porous material noise reduction propeller optimization method. The specific implementation principles of the above modules or units can be referred to the corresponding content in the embodiments of the above porous material noise reduction propeller optimization method, and will not be elaborated here.

[0050] The present invention also correspondingly provides a porous material noise reduction propeller. The porous material noise reduction propeller may include a propeller blade and a rotating shaft. However, it should be understood that it is not required to implement all the shown components, and more or fewer components can be alternatively implemented.

[0051] Correspondingly, the embodiments of the present application also provide a computer-readable storage medium. The computer-readable storage medium is used to store computer-readable programs or instructions. When the programs or instructions are executed by a processor, the steps or functions of the porous material noise reduction propeller optimization method provided in the above method embodiments can be implemented.

[0052] Those skilled in the art can understand that all or part of the processes of implementing the methods in the above embodiments can be completed by instructing relevant hardware (such as a processor, a controller, etc.) through a computer program, and the computer program can be stored in a computer-readable storage medium. Among them, the computer-readable storage medium is a disk, an optical disc, a read-only memory or a random access memory, etc.

[0053] The above has introduced in detail the porous material noise reduction propeller optimization method, device, propeller and storage medium provided by the present invention. Specific examples are used in this article to elaborate on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention; at the same time, for those skilled in the art, according to the idea of the present invention, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A method for optimizing a porous material noise reduction propeller, characterized in that: include: Acquire key attribute parameters of a porous material noise reduction propeller model, and determine multiple radial distances of the porous material in the porous material noise reduction propeller model; the porous material noise reduction propeller model includes a propeller blade composed of a porous material and a solid structure; According to the key property parameters and multiple radial distances, the hydrodynamic characteristics and the acoustic field characteristics of the porous material noise reduction propeller model are calculated to obtain the acoustic field calculation result for each radial distance; The acoustic field calculation result of each radial distance is analyzed and compared with the acoustic field of the original propeller to obtain a comparison result, and the target radial distance of the porous material on the propeller blade is determined according to the comparison result.

2. The porous material noise reduction propeller optimization method according to claim 1 is characterized in that: The hydrodynamic characteristic calculation and the acoustic field characteristic calculation of the porous material noise reduction propeller model are performed according to the key attribute parameters and multiple radial distances to obtain the acoustic field calculation result for each radial distance, including: According to the key attribute parameters, source item parameters are obtained; Calculating the hydrodynamic characteristics of the porous material noise reduction propeller model according to the source term parameters and multiple radial distances to obtain the flow field calculation results for each radial distance; The acoustic field characteristics of the porous material noise reduction propeller model are calculated according to the flow field calculation results to obtain the acoustic field calculation results at each radial distance.

3. The porous material noise reduction propeller optimization method according to claim 2 is characterized in that: The step of obtaining source item parameters according to the key attribute parameters includes: Calculating the key property parameters to obtain the viscous resistance coefficient and the inertial resistance coefficient of the porous material; The viscous drag coefficient and the inertial drag coefficient are input into a preset source term equation for calculation to obtain source term parameters.

4. The porous material noise reduction propeller optimization method according to claim 2 is characterized in that: The hydrodynamic characteristics of the porous material noise reduction propeller model are calculated according to the source term parameters and multiple radial distances to obtain the flow field calculation results of each radial distance, including: Performing polyhedral mesh division on the porous material noise reduction propeller model one by one according to the multiple radial distances to obtain a flow field mesh file for each radial distance; The source term parameters and the flow field grid file are input into a flow field simulation platform to calculate the hydrodynamic characteristics, and the flow field calculation results at each radial distance are obtained.

5. The porous material noise reduction propeller optimization method according to claim 2, characterized in that: The porous material noise reduction propeller model includes a porous material region, a peripheral static region and an intermediate rotating region; The step of calculating the acoustic field characteristics of the porous material noise reduction propeller model according to the flow field calculation result to obtain the acoustic field calculation result for each radial distance includes: Determining an interface according to the peripheral static domain and the intermediate rotating domain; The outer static domain is set as a volume sound source, the interface is set as a surface sound source, and the volume sound source and the surface sound source are acoustically meshed one by one according to the multiple radial distances to obtain an acoustic mesh file for each radial distance; The flow field grid file is input into an acoustic simulation platform to calculate the acoustic field characteristics, and the acoustic field calculation result at each radial distance is obtained.

6. The porous material noise reduction propeller optimization method according to claim 1, characterized in that: The sound field calculation result is a sound pressure level spectrum curve; the sound field calculation result of each radial distance is analyzed and compared with the sound field of the original propeller to obtain a comparison result, including: Comparing the sound pressure level spectrum curve at each radial distance with the original sound pressure level spectrum curve of the original propeller to obtain a target sound pressure level spectrum curve; A comparison result is obtained according to the target sound pressure level spectrum curve.

7. The porous material noise reduction propeller optimization method according to claim 1, characterized in that: The determining of multiple radial distances of the porous material in the porous material noise reduction propeller model comprises: Set the preset porous material area division ratio and initial radius; Determining the preset porous material area division ratio as an initial radial distance; The initial radial distance is equally divided and superimposed according to the preset porous material area division ratio to obtain a plurality of radial distances; the plurality of radial distances are all smaller than the initial radius.

8. A porous material noise reduction propeller optimization device, characterized in that: include: A parameter acquisition module, used to acquire key attribute parameters of a porous material noise reduction propeller model, and determine multiple radial distances of the porous material in the porous material noise reduction propeller model; the porous material noise reduction propeller model includes a propeller blade composed of a porous material and a solid structure; An acoustic field simulation module, used to calculate the hydrodynamic characteristics and acoustic field characteristics of the porous material noise reduction propeller model according to the key attribute parameters and multiple radial distances, and obtain the acoustic field calculation results for each radial distance; The result comparison module is used to analyze and compare the acoustic field calculation result of each radial distance with the acoustic field of the original propeller to obtain a comparison result, and determine the target radial distance of the porous material on the propeller blade according to the comparison result.

9. A porous material noise reduction propeller, characterized in that: The method for optimizing a porous material noise reduction propeller according to any one of claims 1 to 7 is used for optimization.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the porous material noise reduction propeller optimization method according to any one of claims 1 to 7 are implemented.

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